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Open Access Theses & Dissertations
2016-01-01 New Organosilicon Chemistry Paulina Elena Gonzalez Navarro University of Texas at El Paso, [email protected]
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This is brought to you for free and open access by DigitalCommons@UTEP. It has been accepted for inclusion in Open Access Theses & Dissertations by an authorized administrator of DigitalCommons@UTEP. For more information, please contact [email protected]. NEW ORGANOSILICON CHEMISTRY
PAULINA ELENA GONZALEZ NAVARRO Doctoral Program in Chemistry
APPROVED:
Keith H. Pannell, Ph.D., Chair
Hemant K. Sharma, Ph.D.
Rosa Maldonado, Ph.D.
Shizue Mito, Ph.D.
Skye Fortier, Ph.D.
Charles Ambler, Ph.D. Dean of the Graduate School
Copyright ©
by Paulina Elena Gonzalez Navarro
2016
DEDICATION
Este trabajo está dedicado a mi Familia, especialmente a mi Papá, Pepe González, quien me motivó a llegar más lejos, a tener una mayor preparación profesional, a crecer como persona, y a luchar por mis metas. A pesar de que se fue al cielo cuando yo apenas empezaba el doctorado, seguí de pie tratando de corresponder con todo lo que él en vida hizo por mí. A mi Mamá, Ma. Elena Navarro, una mujer hermosa y fuerte, quien es el pilar de la familia y que da todo por sus hijos, que gracias a su amor y el de mis hermanos, me hicieron seguir adelante. A José y Alejandra, mis hermanos, quienes siempre me han apoyado sin importar las circunstancias y por ser los amigos incondicionales. A mi esposo Ricardo, mi compañero de vida, que, gracias a su amor, apoyo y paciencia, este camino se hizo más ligero y placentero.
NEW ORGANOSILICON CHEMISTRY
by
PAULINA ELENA GONZALEZ NAVARRO, B.Sc. in Chemistry
DISSERTATION
Presented to the Faculty of the Graduate School of The University of Texas at El Paso
in Partial Fulfillment of the Requirements for the Degree of
DOCTOR OF PHILOSOPHY
Department of Chemistry THE UNIVERSITY OF TEXAS AT EL PASO
December 2016 ACKNOWLEDGEMENTS
I would like to express my sincere gratitude to my advisor, Dr. Keith H. Pannell, for his expert guidance, constant encouragement, wise knowledge, and motivational enthusiasm shown throughout the course of these years. He is the best mentor that I could have, a great friend and amazing person. I am very thankful he gave me the opportunity to work in his research group, for helping me become a better scientist, and for his support when I most needed it. To Dr. Hemant Sharma, who showed me many laboratory techniques, how to do research and the valuable insights and recommendations. He has been a good friend, always helping me with my projects and for pushing me to improve my skills. I would like to acknowledge my committee members Professors Dr. Shizue Mito, Dr. Skye Fortier, and Dr. Rosa Maldonado for the time and help they spent during the achievement of this dissertation. I also want to thank Dr. Alejandro Metta-Magaña for his assistance in solving X-ray crystal structures of compounds herein presented. Special thanks to Dr. Dale Alexander, who accepted me as his Teacher Assistant in the Periodic Table Laboratory. It was the greatest teaching experience that I could have. He is the best Professor that a student could hope, with his sense of humor, simple experiments and explanations, learning and teaching chemistry was so much fun. I thank my lab mates Isabel Saucedo, Dr. Renzo
Arias, Dr. Robinson Roacho, Dr. Sanchita Chakrabarty, Alexander Craig, Jorge Martinez, and
Raul Cuevas for the science discussions, collaborations, good moments, laughs and all the fun we shared together during these years, and all the students that have done research in Dr. Pannell’s laboratory: Peiyu, Yangjie, Lianqian, Sarah, Alex, Joe, Liz, Matt and David. In addition, I like to thank the faculty and staff from the UTEP Chemistry Department, especially to Dr. Katja Michael and Dr. Mahesh Narayan, for their guidance and help during my doctoral studies. The research was supported by the Robert Welch Foundation, Houston, Texas.
v I gratefully acknowledge my family for all support and unconditional love. Thank you mom and dad for educating me and making me the person that I am now. To my siblings, José and Alejandra, for your support and cheerfulness. To María Jose, the new family member, for bringing happiness in the family. To my husband, Ricardo Perez, for his patience, help and love, for making me laugh even when I was extremely stressed. To my friends, my favorite people, Lizeth Rivera, Griselda Lopez and Lineth Rivera, for being more than friends, thank you for all the sleepless nights, great and bad moments, adventures, for taking care of me when I most needed it, and most importantly for being my family in Texas and allowing me to feel at home. To Marisol Romero, Dr. Danisha Rivera, Dr. Roberto de la Torre, Ana Melendez, and the Gaias soccer team: Iliana, Andrea, Kari, Karen, Galia, and Nalle, for the friendship and all the memorable experiences we have been through. I also thank my grandmas, aunties, uncles and cousins for their support. Finally,
I thank God for blessing me with the most wonderful family, husband, and friends, for the great opportunities and for helping me to achieve the goals in my life. Without all of you, your help and support, this work would never have been possible, THANK YOU!
vi ABSTRACT
The formation of siloxymethylamine intermediates R3SiOCH2NMe2, 1, as initial products of the reduction of DMF by hydrosilanes catalyzed by Mo(CO)5NMe3 has been reported. These siloxymethylamines can react with R’3SiH to form trimethylamine and disiloxanes, and with chlorosilanes to form disiloxanes and ClCH2NMe2, Eschenmoser’s salt. I shall illustrate, in
Chapter 1, how attempts to react 1, formed in situ in the presence of chlorosilanes R’3SiCl in the hope producing heterosilyl disiloxanes, R3SiOSiR’3, was not successful but led to a newly discovered activation of the Si-Cl bond by DMF.
- In Chapter 2, we surmised that 1 acts as a transient siloxy-imminium ion pair [R3SiO]
+ [CH2NMe2] , and further suggested that these intermediates could be useful Mannich reagents, dimethylaminomethyl [Me2NCH2] transfer agents. Furthermore, I shall present the reactions between 1 and compounds with a series of E-H bonds (E = O, S, N) which prove its utility and reliability as a new [CH2NMe2] transfer reagent. We have previously reported the formation of a series of group 14 substituted methanes,
(R3E)nCH4-n (E = Si, Ge, Sn, Pb; R = combinations of methyl and aryl groups; n = 2,3,4). We also used these materials where an R group = C6H5 to form Cr(CO)3 derivatives. During such studies we observed significant C-E bond cleavage products to form (R3E)n-1CH4-n products. It was proposed that the Cr(CO)3 substituent was responsible for this E-C bond activation. Now we have synthesized silicon and germanium homologous compounds with their Cr(CO)3 derivatives, and will study their hydrolytic stability, Chapter 3. Treatment of arenechromiumtricarbonyl complexes with regular n-Bu2O/THF will also be described to illustrate the potential activation of E-C bonds by the transition metal substituent.
vii TABLE OF CONTENTS
DEDICATION ...... III
ACKNOWLEDGEMENTS ...... V
ABSTRACT ...... VII
TABLE OF CONTENTS ...... VIII
LIST OF TABLES ...... XI
LIST OF FIGURES ...... XIII
LIST OF SCHEMES...... XVIII
CHAPTER 1. ACTIVATION OF CHLOROSILANES BY DMF ...... 1
1.1 Abstract ...... 1
1.2 Research Objectives ...... 2
1.3 Introduction ...... 2 1.3.1 Organometallic Chemistry ...... 2 1.3.2 Organosilanes ...... 2 1.3.3 Hydrosilanes ...... 3 1.3.4 Reduction of Amides to Amines ...... 4 1.3.5 Siloxanes ...... 6
1.4 Results and Discussion ...... 7 1.4.1 One-Pot reaction of hydrosilane, chlorosilane, DMF and Mo-catalyst...... 7
1.4.2 Reactions of different hydrosilanes with Me3SiCl...... 9
1.4.3 Reactions of Et3SiH with different chlorosilanes ...... 11 1.4.4 Hydrogen/Chloro exchange at Silicon? ...... 14 1.4.5 Addition of Siloxymethylamine to the initial one-pot reaction...... 15 1.4.6 Silane reduction of Eschenmoser’s salt ...... 18 1.4.7 Chlorosilane/DMF interaction ...... 22 1.4.8 Reduction of the (Chloromethylene)dimethyliminium Chloride by Hydrosilane ...... 23 1.4.9 Proposed mechanism for the one-pot reaction...... 24
viii 1.4.10 Reactions involving Et3SiH and Me3SiI ...... 26
1.4.11 One-Pot reaction using Chlorogermane or -stannane with Et3SiH ...... 29
1.5 Conclusions ...... 32
1.6 Experimental ...... 32 1.6.1 One-Pot reaction of hydrosilane, chlorosilane, DMF and Mo-catalyst...... 33 1.6.2 Hydrogen/Chloro exchange at Silicon? ...... 33 1.6.3 Addition of Siloxymethylamine to the initial one-pot reaction...... 34 1.6.4 Silane reduction of Eschenmoser’s salt ...... 34 1.6.5 Reduction of the (Chloromethylene)dimethyliminium Chloride by Hydrosilane ...... 34
1.6.6 Reactions involving Et3SiH and Me3SiI ...... 34
1.6.7 One-Pot reaction using Chlorogermane or -stannane with Et3SiH ...... 35
1.7 References ...... 35
CHAPTER 2. SILOXYMETHYLAMINE, A MASKED ANALOGUE OF ESCHENMOSER’S SALT (MANNICH REAGENT) ...... 38
2.1 Abstract ...... 38
2.2 Research Objectives ...... 38
2.3 Introduction ...... 39
2.4 Results and Discussion ...... 41
2.4.1 Reactions of Et3SiOCH2NMe2 with Aliphatic Alcohols ...... 42
2.4.2 Reactions of Et3SiOCH2NMe2 with Aromatic Alcohols ...... 43
2.4.3 Reactions of Et3SiOCH2NMe2 with Cholesterol ...... 48
2.4.4 Reactions of Et3SiOCH2NMe2 with Aliphatic Thiols ...... 49
2.4.5 Reactions of Et3SiOCH2NMe2 with Aromatic Thiols ...... 50
2.5 Conclusions ...... 52
2.6 Experimental ...... 53
2.6.1 Reactions of Et3SiOCH2NMe2 with Alcohols and thiols, 2-3...... 53
2.6.2 Reactions of Et3SiOCH2NMe2 with Cholesterol to form 2j...... 56
2.6.3 Reactions of Et3SiOCH2NMe2 with 1- and 2-naphthol ...... 57
ix 2.7 References ...... 58
CHAPTER 3. ARENECHROMIUMTRICARBONYL COMPLEXES OF THE MIXED GROUP 14 METHANES ...... 61
3.1 Abstract ...... 61
3.2 Research Objectives ...... 61
3.3 Introduction ...... 62 3.3.1 The Carbon Family ...... 62 3.3.2 Catorcanes ...... 62 3.3.3 Metallocenes ...... 63 3.3.4 Arene-Chromium Tricarbonyl complexes ...... 63 3.3.5 Synthesis of (Halomethyl)silanes ...... 68 3.3.6 Organomagnesium Reagents ...... 68
3.4 Results and Discussion ...... 69 3.4.1 Synthesis of (halomethyl)-silane and -germane ...... 70 3.4.2 Synthesis of Di-substituted Methanes ...... 71 3.4.3 Formation of the Arene-Chromium Tricarbonyl Derivatives ...... 72 3.4.4 Hydrolysis Reaction ...... 77
3.5 Conclusions ...... 78
3.6 Experimental ...... 79 3.6.1 Synthesis of (halomethyl)-silane and -germane derivatives ...... 79 3.6.2 Synthesis of Arene-Chromium Tricarbonyl Derivatives ...... 80 3.6.3 Synthesis and Reaction of Grignard Reagents ...... 82 3.6.4 Hydrolytic Study ...... 82
3.7 References ...... 84
APPENDIX ...... 87
VITA ...... 159
x LIST OF TABLES
Table 1.1 Relative yields of the disiloxanes formed at RT and 50 °C for the reactions of R3SiH and Me3SiCl. The last column designates the time when the starting R3SiH was consumed...... 10 Table 1.2 Relative yields of the disiloxanes and chlorosilane obtained from RT to 50 °C for the reactions of Et3SiH and R3SiCl. The last column designates the time when the starting Et3SiH is consumed...... 12 Table 1.3 Relative yields of the disiloxanes formed at RT and 50 °C for the reaction of Et3SiH, Me3SiCl, DMF and Mo-catalyst (1:1:1:5%). The last column designates the time when the starting Et3SiH was consumed...... 13 Table 1.4 Reactions to probe H/Cl exchange at silicon based on eq. 1.9...... 14 - + Table 1.5 Results from the reduction of [Cl] [CH2NMe2] by R3SiH under different conditions. 19 - + Table 1.6 Results from the reduction of [Cl] [ClCHNMe2] by Et3SiH (eq. 1.16) ...... 24 Table 2.1 Reaction of aliphatic thiols and siloxymethylamine intermediates, eq. 2.9...... 49 Table A.1 Calculation of the relative yields of the disiloxanes formed at room temperature from 1 the above reaction and H NMR spectrum in C6D6 (Table 1.1)...... 87 Table A.2 Calculation of the relative yields of the disiloxanes formed at room temperature from 1 the above reaction and H NMR spectrum in C6D6 (Table 1.1) ...... 92 Table A.3 Siloxane formation of one-pot reaction, described above, using different hydrosilanes and chlorosilanes with DMF and Mo-catalyst (1:1:5:5%)...... 98 Table A.4 Sample and crystal data for 2f (1085KPPG)...... 123 Table A.5 Data collection and structure refinement for 2f (1085KPPG)...... 123 Table A.6 . Bond lengths (Å) for 2f (1085KPPG)...... 124 Table A.7 Bond angles (°) for 2f (1085KPPG)...... 124 Table A. 8 Torsion angles (°) for 2f (1085KPPG)...... 125 Table A.9 Sample and crystal data for 2i (1247KP)...... 128 Table A.10 Data collection and structure refinement for 2i (1247KP)...... 129 Table A.11 Bond lengths (Å) for 2i (1247KP)...... 129 Table A.12 Bond angles (°) for 2i (1247KP)...... 130 Table A.13 Torsion angles (°) for 2i (1247KP)...... 130 Table A. 14 Sample and crystal data for 2j (976KP)...... 134 Table A.15 Data collection and structure refinement for 2j (976KP)...... 134 Table A.16 Bond lengths (Å) for 2j (976KP)...... 135 Table A.17 Bond angles (°) for 2j (976KP)...... 136 Table A.18 Torsion angles (°) for 2j (976KP)...... 138 Table A.21 Crystal data and structure refinement for 2a (369PG_0mS)...... 154 Table A.22 Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) for 2a (369PG_0mS). U(eq) is defined as one third of the trace of the orthogonalized Uij tensor ...... 154 Table A.23 Bond lengths [Å] and angles [°] for 2a (369PG_0mS)...... 155 Table A.24 Anisotropic displacement parameters (Å2x 103) for 2a (369PG_0mS). The anisotropic displacement factor exponent takes the form: -22[ h2 a*2U11 + ... + 2 h k a* b* U12]...... 156
xi Table A.25 Hydrogen coordinates (x 104) and isotropic displacement parameters (Å2x 10 3) for 2a (369PG_0mS)...... 157 Table A.26 Torsion angles [°] for 2a (369PG_0mS)...... 157
xii LIST OF FIGURES
29 Figure 1.1 Si NMR monitoring of the reaction of Et3SiH, Me3SiCl, DMF and catalyst in C6D6 at RT (left) and at 50 °C (right): Et3SiH = -0.04 ppm; Me3SiOSiEt3 = 6.15, 9.35 ppm; Me3SiOSiMe3 = 6.84 ppm; Et3SiOSiEt3 = 8.70 ppm; Me3SiCl = 30.84 ppm; Et3SiCl = 36.05 ppm...... 8 13 Figure 1.2 C NMR monitoring of the reaction of Et3SiH, Me3SiCl, DMF and catalyst in C6D6 at RT (left) and at 50 °C (right), showing the presence of Me3N at ~47 ppm...... 9 Figure 1.3 Relative yields of the disiloxanes obtained at room temperature from the reactions of R3SiH (R3 = Et3, PhMe2, Ph2Me) and Me3SiCl...... 10 Figure 1.4 Relative yields of the disiloxanes obtained at 50 °C from the reactions of R3SiH (R3 = Et3, PhMe2, Ph2Me) and Me3SiCl...... 11 Figure 1.5 Relative yields of the disiloxanes obtained from the reactions of Et3SiH and R3SiCl (R3 = Et3, PhMe2, Ph2Me, Ph3)...... 13 29 13 Figure 1.6 Si NMR (left) and C NMR monitoring of the reaction of Et3SiOCH2NMe2, Et3SiH, Me3SiCl, DMF and catalyst in C6D6 at RT for 22 hours plus another 48 hours at 50 °C (denoted in red color)...... 16 Figure 1.7 Physical appearance of the NMR tube of the reaction...... 17 Figure 1.8 29Si NMR (left) and 13C NMR monitoring of the reaction of Eschenmoser’s salt with PhMe2SiH, in C6D6 at 90 °C under different conditions described in Table 1.5: with DMF (i, entry 1), with catalyst (ii, entry 2), with DMF and catalyst (iii, entry 3)...... 21 29 Figure 1.9 Si NMR monitoring of the reaction of Et3SiH, Me3SiI, DMF and catalyst in C6D6 at RT (left) and at 50 °C (right): Et3SiH = -0.04 ppm; Me3SiOSiMe3 = 7.14 ppm; Et3SiI = 41.22 ppm; Me3SiI = 41.94 ppm...... 27 13 Figure 1.10 C NMR monitoring of the reaction of Et3SiH, Me3SiI, DMF and catalyst in C6D6 at RT (left) and at 50 °C (right), showing the presence of Me3N at ~47 ppm...... 28 29 13 Figure 1.11 Si NMR (left) and C NMR (right) monitoring of the reaction of Et3SiH, Me3GeCl, DMF and catalyst in C6D6 at room temperature...... 29 Figure 1.12 29Si NMR (left), 13C NMR (middle) and 119Sn NMR (left) monitoring of the reaction of Et3SiH, Me3SnCl, DMF and catalyst in C6D6 at room temperature...... 30 Figure 2.1 Structure of 2,6-dimethyl-4-dimethylaminomethyl phenol, 2f...... 44 13 Figure 2.2 C NMR spectrum of 2f in CDCl3: 16.12 (Me), 45.25 (N(Me)2), 63.91 (CH2), 123.65, 129.58, 129.85, 151.72 ppm (Ph)...... 44 Figure 2.3 Structures of the 2-[(dimethylamino)methyl]-1- naphthalenol, 2g (left), and 1- [(dimethylamino)methyl]-2-naphthalenol, 2h (right), derivatives...... 45 Figure 2.4 Single X-Ray crystal structure of 2,4-bis[(dimethylamino)methyl]-1-naphthalenol, 2i...... 46 Figure 2.5 NMR monitoring of the formation of 2i...... 47 Figure 2.6 Structure of cholesteromethyl(dimethyl)amine, 2j...... 48 13 Figure 2.7 C NMR spectrum of EtSCH2NMe2, 3a...... 50 Figure 2.8 13C NMR spectrum of derivative 3e...... 51 Figure 2.9 Decomposition of 3e, formation of S-S bond...... 52 Figure 3.1 Structure of a catorcane...... 62 Figure 3.2 (η6-arene)chromium tricarbonyl, “piano stool” geometry...... 64
xiii Figure 3.3 Aromatic Ring Current...... 66 Figure 3.4 (arene)tricarbonylchromium-silane and -germane derivatives...... 69 29 13 Figure 3.5 Si NMR (left) and C NMR (right) spectra of 5a in CDCl3...... 71 29 13 Figure 3.6 Si NMR (left) and C NMR (right) spectra of 1a in CDCl3...... 72 Figure 3.7 Single X-Ray structure of 6a...... 73 Figure 3.8 Section of the crystal packing of 6a, showing the HB network...... 74 29 13 Figure 3.9 Si NMR (left) and C NMR (right) spectra of 6a in CDCl3...... 75 Figure 3.10 Single X-Ray crystal structure of 2a complex...... 76 29 13 Figure 3.11 Si NMR (left) and C NMR (right) spectra of 2a in C6D6...... 76 Figure 3.12 Homologous derivatives with Si, Sn and Ge...... 78 1 Figure A.1 H NMR spectrum of the above reaction at room temperature in C6D6 (Table 1.1). . 87 1 Figure A.2 H NMR spectrum of the above reaction at 50 °C in C6D6 (Table 1.1)...... 88 29 13 Figure A.3 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature (Table 1.1)...... 89 1 Figure A.4 H NMR spectrum of the above reaction at room temperature in C6D6 (Table 1.1). . 89 29 13 Figure A.5 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 50 °C (Table 1.1)...... 90 1 Figure A.6 H NMR spectrum of the above reaction at 50 °C in C6D6 (Table 1.1)...... 90 29 13 Figure A.7 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature (Table 1.1)...... 91 1 Figure A.8 H NMR spectrum of the above reaction at room temperature in C6D6 (Table 1.1). . 91 29 13 Figure A.9 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 50 °C (Table 1.1)...... 92 1 Figure A.10 H NMR spectrum of the above reaction at 50 °C in C6D6 (Table 1.1)...... 92 29 13 Figure A.11 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 50 °C (Table 1.1)...... 93 1 Figure A.12 H NMR spectrum of the above reaction at 50 °C in C6D6 (Table 1.1)...... 93 29 13 Figure A.13 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 21 hours plus 3 hours at 50 °C, denoted in red color (Table 1.2)...... 94 1 Figure A.14 H NMR spectrum of the above reaction in C6D6 (Table 1.2)...... 94 29 13 Figure A.15 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 3 hours plus 1 hour at 50 °C, denoted in red color (Table 1.2)...... 95 1 Figure A.16 H NMR spectrum of the above reaction in C6D6 (Table 1.2)...... 95 29 13 Figure A.17 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 15 minutes plus 17 hours at 50 °C, denoted in red color (Table 1.2)...... 96 1 Figure A.18 H NMR spectrum of the above reaction in C6D6 (Table 1.2)...... 96 29 13 Figure A.19 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 19 hours plus 102 hours at 50 °C, denoted in red color (Table 1.2)...... 97 1 Figure A.20 H NMR spectrum of the above reaction in C6D6 (Table 1.2)...... 97 29 13 Figure A.21 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 3 hours plus 6 hours at 50 °C, denoted in red color (Table 1.2)...... 99 1 Figure A.22 H NMR spectrum of the above reaction in C6D6 (Table 1.2)...... 99 29 13 Figure A.23 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 15 hours plus 4 hours at 50 °C, denoted in red color (Table 1.2)...... 100 1 Figure A.24 H NMR spectrum of the above reaction in C6D6 (Table 1.2)...... 100
xiv 29 13 Figure A.25 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 19 hours plus 25 hours at 50 °C, denoted in red color (Table 1.2)...... 101 1 Figure A.26 H NMR spectrum of the above reaction in C6D6 (Table 1.2)...... 101 29 13 Figure A.27 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 17 hours plus 9 hours at 50 °C, denoted in red color (Table 1.2)...... 102 1 Figure A.28 H NMR spectrum of the above reaction in C6D6 (Table 1.2)...... 102 29 13 Figure A.29 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 18.5 hours plus 3.5 hours at 50 °C, denoted in red color (Table 1.2)...... 103 1 Figure A.30 H NMR spectrum of the above reaction in C6D6 (Table 1.2)...... 103 29 13 Figure A.31 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 18.5 hours plus 14 hours at 50 °C, denoted in red color (Table 1.2)...... 104 1 Figure A.32 H NMR spectrum of the above reaction in C6D6 (Table 1.2)...... 104 29 13 Figure A.33 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 17 hours plus 23 hours at 50 °C, denoted in red color (Table 1.2) ...... 105 1 Figure A.34 H NMR spectrum of the above reaction in C6D6 (Table 1.2)...... 105 29 13 Figure A.35 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature (Table 1.3)...... 106 1 Figure A.36 H NMR spectrum of the above reaction in C6D6 (Table 1.3)...... 106 29 13 Figure A.37 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 50 °C (Table 1.3)...... 107 1 Figure A.38 H NMR spectrum of the above reaction in C6D6 (Table 1.3)...... 107 29 13 Figure A.39 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 90 °C (Table 1.5, entry 4)...... 108 29 13 Figure A.40 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 90 °C (Table 1.5, entry 5)...... 108 29 13 Figure A.41 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 90 °C (Table 1.5, entry 6)...... 109 29 13 Figure A.42 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 50 °C (Table 1.6, entry 2)...... 109 29 13 Figure A.43 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature (Table 1.6, entry 3)...... 110 29 13 Figure A.44 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 50 °C (Table 1.6, entry 4)...... 110 29 13 Figure A.45 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature (Table 1.6, entry 5) ...... 111 29 13 Figure A.46 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 50 °C (Table 1.6, entry 6)...... 111 29 13 Figure A.47 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature (Table 1.6, entry 7)...... 112 13 Figure A.48 C NMR spectrum of (chloromethylene)dimethyliminium chloride in CDCl3. .... 112 29 13 Figure A.49 Si NMR (left) and C NMR (right) spectra of Me3SiI in C6D6...... 113 1 Figure A.50 H NMR spectrum of the above reaction at room temperature in C6D6 (Fig. 1.11)...... 113 1 Figure A.51 H NMR spectrum of the above reaction at room temperature in C6D6 (Fig. 1.12)...... 114 13 Figure A.52 C NMR spectrum of MeOCH2NMe2, 2a, in C6D6...... 115
xv 1 Figure A.53 H NMR spectrum of MeOCH2NMe2, 2a, in C6D6...... 115 13 Figure A.54 C NMR spectrum the above reaction to form MeOCH2NMe2, 2a, in C6D6...... 116 13 Figure A.55 C NMR spectrum of EtOCH2NMe2, 2b, in C6D6...... 117 1 Figure A.56 H NMR spectrum of EtOCH2NMe2, 2b, in C6D6...... 117 13 Figure A.57 C NMR spectrum the above reaction to form EtOCH2NMe2, 2b, in C6D6...... 118 13 i Figure A.58 C NMR spectrum of PrOCH2NMe2, 2c, in C6D6...... 119 1 i Figure A.59 H NMR spectrum of PrOCH2NMe2, 2c, in C6D6...... 119 13 Figure A.60 C NMR spectrum of 2-((dimethylamino)methyl)phenol, 2e, in CDCl3...... 120 1 Figure A.61 H NMR spectrum of 2-((dimethylamino)methyl)phenol, 2e, in CDCl3...... 120 Figure A.62 13C NMR spectrum of 4-((dimethylamino)methyl)-2,6-dimethylphenol, 2f, in CDCl3...... 121 1 Figure A.63 H NMR spectrum of 4-((dimethylamino)methyl)-2,6-dimethylphenol, 2f, in CDCl3...... 121 Figure A.64 Single X-Ray crystal structure of 2,6-dimethyl-4-dimethylaminomethyl phenol, 2f...... 122 Figure A.65 13C NMR spectrum of 2,4-bis[(dimethylamino)methyl]-1-naphthalenol, 2i, in CDCl3...... 125 Figure A.66 13C DEPT135 NMR spectrum of 2,4-bis[(dimethylamino)methyl]-1-naphthalenol, 2i, in CDCl3...... 126 1 Figure A.67 H NMR spectrum of 2,4-bis[(dimethylamino)methyl]-1-naphthalenol, 2i, in CDCl3...... 126 Figure A.68 13C NMR spectrum the above reaction to form 2,4-bis[(dimethylamino)methyl]-1- naphthalenol, 2i, in CDCl3...... 127 Figure A.69 Single X-Ray crystal structure of 2,4-bis[(dimethylamino)methyl]-1-naphthalenol, 2i...... 127 Figure A.70 13C NMR spectrum the above reaction to form 1-[(dimethylamino)methyl]-2- naphthalenol, 2h, in CDCl3...... 131 13 13 Figure A.71 a) C NMR spectrum of Cholesterol (starting material) in C6D6. b) C NMR spectrum of Cholesteromethyl(dimethyl)amine, 2j, in C6D6; the green arrows indicate the new 13 peaks: methylene (O-CH2-N) at 87.5 ppm and dimethylamine (N(CH3)2) at 41.7 ppm. c) C DEPT135 NMR spectrum of Cholesteromethyl(dimethyl)amine, 2j, in C6D6...... 132 1 Figure A.72 H NMR spectrum of Cholesteromethyl(dimethyl)amine, 2j, in C6D6...... 133 Figure A.73 Single X-Ray crystal structure of Cholesteromethyl(dimethyl)amine, 2j...... 133 13 Figure A.74 C NMR spectrum of EtSCH2NMe2, 3a, in C6D6 (Table 2.1, entry 1)...... 139 1 Figure A.75 H NMR spectrum of EtSCH2NMe2, 3a, in C6D6 (Table 2.1, entry 1)...... 139 13 Figure A.76 C NMR spectrum of PrSCH2NMe2, 3b, in C6D6 (Table 2.1, entry 3)...... 140 1 Figure A.77 H NMR spectrum of PrSCH2NMe2, 3b, in C6D6 (Table 2.1, entry 3)...... 140 13 Figure A.78 C NMR spectrum the above reaction to form PrSCH2NMe2, 3b, in C6D6 (Table 2.1, entry 2)...... 141 13 Figure A.79 C NMR spectrum of BuSCH2NMe2, 3c, in C6D6 (Table 2.1, entry 5)...... 142 1 Figure A.80 H NMR spectrum of BuSCH2NMe2, 3c, in C6D6 (Table 2.1, entry 5)...... 142 Figure A.81 Mass spectrum (ESI+) for BuSCH2NMe2, 3c (Table 2.1, entry 5)...... 143 13 Figure A.82 C NMR spectrum the above reaction to form BuSCH2NMe2, 3c, in C6D6 (Table 2.1, entry 4)...... 143 13 Figure A.83 C NMR spectrum of N,N-dimethyl-1-(phenylthio)methanamine, 3d, in C6D6. .. 144
xvi Figure A.84 13C DEPT135 NMR spectrum of N,N-dimethyl-1-(phenylthio)methanamine, 3d, in C6D6...... 145 1 Figure A.85 H NMR spectrum of N,N-dimethyl-1-(phenylthio)methanamine, 3d, in C6D6. ... 145 Figure A.86 13C NMR spectrum of 1-((2,6-dimethylphenyl)thio)-N,N-dimethylmethanamine, 3e, in CDCl3...... 146 Figure A.87 1H NMR spectrum of 1-((2,6-dimethylphenyl)thio)-N,N-dimethylmethanamine, 3e, in CDCl3...... 146 1 Figure A.88 H NMR spectrum of 5a in CDCl3...... 147 1 Figure A.90 H NMR spectrum of 5b in CDCl3...... 148 1 Figure A.91 H NMR spectrum of 1a in CDCl3...... 149 Figure A.92 Single X-Ray crystal structure of 6a...... 149 1 Figure A.93 H NMR spectrum of 6a in CDCl3...... 151 13 Figure A.94 C NMR spectrum of 6b in C6D6...... 151 13 Figure A.95 C DEPT135 NMR spectrum of 6b in C6D6...... 152 1 Figure A.96 H NMR spectrum of 6b in C6D6...... 152 1 Figure A.97 H NMR spectrum of 2a in C6D6...... 153 Figure A.98 Single X-Ray crystal structure of 2a...... 153
xvii LIST OF SCHEMES
Scheme 1.1 Possible route to form mixed disiloxanes...... 1 Scheme 1.2 Hydrosilylation reactions...... 4 Scheme 1.3 Formation of disiloxane and trimethylamine...... 6 Scheme 1.4 Reaction of the Eschenmoser’s salt with PhMe2SiH...... 20 Scheme 1.5 Interaction of DMSO and chlorosilanes reported by Weber.23 ...... 22 Scheme 1.6 Interaction of DMF and chlorosilane...... 23 Scheme 1.7 Proposed mechanism for the one-pot in situ reaction to form ‘unsymmetrical disiloxanes’...... 25 Scheme 2.1 Reaction of 1a with aromatic alcohols...... 43 Scheme 2.2 Reactions 1a or 1c with 1-naphthol to form derivative 2i...... 45 Scheme 2.3 Reactions of 1a and aromatic thiols...... 51 Scheme 3.1 Synthetic route to prepare the (arene)tricarbonyl chromium derivatives...... 68 Scheme 3.2 Halogen/Magnesium exchange reactions...... 69 Scheme 3.3 Hydrolysis reactions using wet solvents (i, ii) or different acids and bases (iii)...... 77
xviii CHAPTER 1. ACTIVATION OF CHLOROSILANES BY DMF
1.1 Abstract
The synthesis and isolation of siloxymethylamine intermediates, R3SiOCH2NMe2, 1, as initial products of the reduction of DMF by hydrosilanes catalyzed by Mo(CO)5NMe3 has been reported by Arias-Ugarte et al in 2012.1 These siloxymethylamines have the capacity to react with
2 R’3SiH to form trimethylamine and disiloxanes, and with chlorosilanes to form disiloxanes and
ClCH2NMe2, Eschenmoser’s salt. This latter reaction is instantaneous, and the Eschenmoser’s salt precipitates out from the solution making an easy product separation. We inferred that 1 acts as a
- + transient siloxy-imminium ion pair [R3SiO] [CH2=NMe2] . The rapid reaction of 1 with chlorosilane suggested that there is a possible route to form non-symmetrical disiloxanes via a one-pot reaction involving R3SiH, R’3SiCl and DMF in the presence of the molybdenum catalyst, Scheme 1.1.
Scheme 1.1 Possible route to form mixed disiloxanes.
I shall illustrate how attempts to react 1, formed in situ in the presence of chlorosilanes
R’3SiCl in the hope producing heterosilyl disiloxanes, R3SiOSiR’3, was not successful. However, the reaction led to the major formation of R’3SiOSiR’3 and R3SiCl, demonstrating an
1 unprecedented DMF activation of a chlorosilane. The reaction appears quite general for a range of silanes and chlorosilanes.
1.2 Research Objectives
The basic objective of this portion of our research was to test the efficacy and generality of the one-pot reaction outlined in Scheme 1.1. Prior to examining the results obtained, a brief background related to organosilicon systems is provided
1.3 Introduction
1.3.1 Organometallic Chemistry
The general field of organometallic chemistry is now a separate and mature area of chemistry, widely utilized in catalysis, organic synthesis, electronics, etc.3 Organometallic compounds are those that contain metal—carbon (M-C) bond. Normally, these are compromised of not only compounds with typical metals, but also with metalloids such as boron, silicon, phosphorus, arsenic, selenium, etc. The M-C bond is generally polarized as Mδ+ ̶ Cδ-, thus, the carbon atom will be susceptible to electrophilic attack while the metalloid or metal atom will be susceptible to nucleophilic attack.4
1.3.2 Organosilanes
Silicon is the second most abundant element on the Earth’s crust. It does not occur in the free state, being found primarily in combination with oxygen, the most abundant element, as silica
2 or metal silicates.3 Monomeric silicon compounds are known as silanes. If a silane contains at least one C-Si bond structure is call organosilane. The development of C-Si bond also represented a major early challenge in chemistry. Whereas Berzelius in 1823 prepared tetrachlorosilane, SiCl4, and Buff and Wöhler successfully prepared trichlorosilane, Cl3SiH in 1857, it was until 1863 when Friedel and Crafts prepared the first organosilane, tetraethylsilane. Today organosilicon chemistry represents a major contribution to organic chemistry.5 This is both as a protecting group and as a synthon for a variety of chemical transformations. The C-Si bonds can withstand a wide variety of reaction conditions and reagents, yet they have a latent lability. Reactions such as catalytic hydrogenation, hydroboration, hydroalumination, organometallic nucleophilic addition reactions, have all been performed on organosilicon compounds without C-Si bond cleavage.6 In general, organosilanes display many attractive properties compared with other organometallic reagents: they can be handle freely, they are much more moisture- and air-stable without the necessity for inert atmospheres, made from cheap silicon raw material abundant on earth, low toxicity, etc.
1.3.3 Hydrosilanes
Hydrosilanes, i.e. silanes with one or more hydrogen-silicon bonds, have the ability to behave as reducing agents. The reducing properties of hydrosilanes are generally safer and more easily handled and disposed of than traditional reducing agents such lithium aluminium hydride, boranes or tributhyltin hydride.7 The capacity of hydrosilanes to form Si-C bonds via the well- established hydrosilylation reaction is one of the most significance features of these compounds. This reaction is often a transition metal-catalyzed process which allows the addition of organic and inorganic silicon hydrides to a multiple-bonded system, in particular C-C and C-heteroatom bonds, likewise heteroatom-heteroatom bonds.4-5,8 The addition of the Si-H bond to multiple bonded substrates is important not only as a method of reduction, but also as a major route to complex organosilanes. The most commonly
3 utilized reagents, in hydrosilylation reactions, are hydrosilanes (R3SiH, R = halogen, H, OR, alkyl and aryl groups) and the unsaturated substrates are olefins, acetylenes, ketones, imines, etc., Scheme 1.2.5
Scheme 1.2 Hydrosilylation reactions.
1.3.4 Reduction of Amides to Amines
In 2007, the ACS Green Chemistry Institute published a ‘dream’ list of reactions used in the production of pharmaceuticals, agrochemicals, dyes and other industrial products that need environmental solutions to make them more safe and economical. One of the reactions was the
9 reduction of amides to amines avoiding LiAlH4 or NaBH4 (eq. 1.1).
(1.1)
Thus, the mild reaction condition reductions of organic substrates using organosilane and variety of catalysts has developed into a major area of industrial and academic chemistry. The organosilanes (R4-nSiHn) used in this now-popular route to reduce, for example amides, illustrate
4 the weakly hydridic character of the Si-H bond.10 Reduceding energy consumption and waste side products also recommend this process.9 In 1985, the Voronkov group were the first to described a metal-catalyzed amide (dimethylformamide, DMF) reduction by silane resulting in the formation of the corresponding disiloxane and trimethylamine (eq. 1.2).11 Multiple research groups reported the reduction of amides into amines by silanes using a huge variety of metal complexes as catalyst.10,12 The mechanism of the reduction was not clear after those attempts, only suggestions of the mechanism were proposed.
(1.2)
In 2012 our group reported a mechanism for the Mo-catalyzed reduction of DMF using tertiary silanes, germanes and stannanes.13 The initial step in the process involved a hydrosilylation of the carbonyl group of the amide to yield a siloxymethylamine intermediate that had not been previously observed with molybdenum catalyst (eq. 1.3).
(1.3)
Thus, overall the procedure consists of a dual step mechanism, the initial hydrosilylation step resulting in the formation of the siloxymethylamine intermediate R3SiOCH2NMe2, 1, followed by second step in which 1 reacts with more silane to yield the isolated products (eq. 1.3).
5 The intermediates 1 were isolated, characterized, and the second step was demonstrated either catalyzed by a metal complex, or simply by a DMF activation of the silane (Scheme 1.3).2,13
Scheme 1.3 Formation of disiloxane and trimethylamine.
Clearly, when using a Mo(CO)5(Me3N) as a catalyst, the first step is faster than the second step, hence our ability to isolate the siloxymethylamine intermediates 1. Only a single example of this class of material, Me3SiOCH2NMe2, was reported by Mironov group in 1981, produced by
14 the condensation reaction of trimethylsilylamine, Me3SiNMe2, and formaldehyde.
1.3.5 Siloxanes
Disiloxanes are an important class of compounds and some are known to have significant applications as liquid-crystalline polymers, pharmacologically active compounds, resins, etc.15
Looking in the literature, the reactions reported on the formation of unsymmetrical disiloxanes are not simple and require the use of catalyst and obtained low yields. These methods involve intermolecular condensation of silanols (eq. 1.4),16 a non-aqueous method by Lewis acid-catalyzed air oxidation of hydrosilanes (eq. 1.5),17 rhodium(I)-catalyzed dehydrocoupling of silanols with hydrosilanes,18 oxidation of tertiary silanes using silver nanoparticles, or dealkylative coupling of hydrosilanes with alkoxysilanes,19 giving silanols in good yields but low yields of disiloxanes.20
(1.4)
(1.5)
6 In 1983, the Mironov group21 and later our group,2b showed the capacity of the
2b,21 2b δ+ δ- siloxymethylamines to react with chloro-silanes, -germanes, and –stannanes (R3E -Cl , E
2b = Si, Ge, Sn) to form the corresponding ClCH2NMe2 and R3SiOER3 respectively (eq. 1.6). This reaction is instantaneous, and a catalyst is not required. In addition, the secondary product,
ClCH2NMe2, precipitates out from the solution resulting in a simple product separation.
(1.6)
The facile and immediate reaction of 1 with chlorosilanes suggested that there was a possible route to form non-symmetrical disiloxanes, species not readily available by simple one pot chemistry, via a reaction involving R3SiH, R’3SiCl and DMF in the presence of the molybdenum catalysts we have developed. The hypothesis is that the initial reaction to form intermediate 1 is fast, and its subsequent reaction with more SiH material to form Me3N and the disiloxane is slow. However, as noted above, the reaction of 1 with chlorosilanes is very rapid, hence we could intercept 1 as it formed with a different chlorosilane, Scheme 1.1.
1.4 Results and Discussion
1.4.1 One-Pot reaction of hydrosilane, chlorosilane, DMF and Mo-catalyst.
The initial study concerning the one-pot reaction to form a mixed disiloxane and
ClCH2NMe2, was monitored in a C6D6 solution by NMR spectroscopy, using equimolar amounts of Et3SiH and Me3SiCl with 5-fold excess of DMF and Mo(CO)5(NMe3)-catalyst (5 mol%). We have to point it out as an important issue for all this research, this is a one-step reaction for the
7 simple formation of siloxanes and chlorosilane in a closed system and non-aqueous environment (Fig. 1.1).
29 Figure 1.1 Si NMR monitoring of the reaction of Et3SiH, Me3SiCl, DMF and catalyst in C6D6 at RT (left) and at 50 °C (right): Et3SiH = -0.04 ppm; Me3SiOSiEt3 = 6.15, 9.35 ppm; Me3SiOSiMe3 = 6.84 ppm; Et3SiOSiEt3 = 8.70 ppm; Me3SiCl = 30.84 ppm; Et3SiCl = 36.05 ppm.
The chemistry produced unexpected products, where the reaction at RT reveals the formation of Et3SiCl and Me3SiOSiMe3 as major products after 6 days. Performing the reaction at 50 °C, resulted in completion within a few hours. The reaction at higher temperature showed the formation of the mixed disiloxane (Me3SiOSiEt3) and Et3SiOSiEt3 along with Me3SiOSiMe3 in somewhat higher amounts than the reaction at room temperature. Besides the formation of silicon
13 derivatives, the presence of the Me3N product was observed on C NMR spectra at ~47 ppm (Fig. 1.2). It is important to note that the relative product yields at the elevated temperature are identical after 3 hours and 3 days, thus no scrambling chemistry was observed.
8
13 Figure 1.2 C NMR monitoring of the reaction of Et3SiH, Me3SiCl, DMF and catalyst in C6D6 at RT (left) and at 50 °C (right), showing the presence of Me3N at ~47 ppm.
1.4.2 Reactions of different hydrosilanes with Me3SiCl
Changing the nature of the R3SiH and maintaining the Me3SiCl system (eq. 1.7), similar results were observed (Table 1.1). For simplicity purpose of this chapter, the silicon compound in red color is designated for the starting hydrosilane group (R3SiH or R3SiH), whereas in blue color will be for the correspondent chlorosilane (R3SiCl or R’3SiCl).
(1.7)
The reaction time for the consumption of the R3SiH seem to correlates with the size of the silyl group (Et3Si > PhMe2Si > Ph2MeSi > Ph3) as going from few hours to days. The relative yields of the products were determined by 1H NMR spectroscopy. The NMR monitoring spectra for these reactions are provided in the appendix section (A 1.1-1.7). The results are consistent in the sense that the major and first product formed is the symmetrical disiloxane (R3SiOSiR3) from the initial chlorosilane. Consequently, the new
9 chlorosilane (R3SiCl) appears along with the production of NMe3. The expected product, the unsymmetrical disiloxane, is the next product of the reaction. The last product to be formed is the symmetrical disiloxane (R3SiOSiR3) which comes from the R3SiH. When the R3SiH was completely consumed, we determined the reaction was finished, because after that point, no further changes are noted. At the end of the reaction, a part of the R3SiCl remains. The relative yields of the disiloxanes, determined by 1H NMR spectroscopy, are presented in Table 1.1, and graphically in Fig. 1.3-1.4.
Table 1.1 Relative yields of the disiloxanes formed at RT and 50 °C for the reactions of R3SiH and Me3SiCl. The last column designates the time when the starting R3SiH was consumed.
R3 Me3SiOSiMe3 Me3SiOSiR3 R3SiOSiR3 Temp. Time Et 85% 15% 0 RT 6 d 3 60% 21% 19% 50 °C 3 h PhMe 50% 35% 15% RT 8 d 2 41% 44% 15% 50 °C 5 h Ph Me 60% 34% 6% RT 17 d 2 48% 42% 10% 50 °C 5 h Ph - - - RT 19 d 3 21% 14% 65% 50 °C 7 d
Figure 1.3 Relative yields of the disiloxanes obtained at room temperature from the reactions of R3SiH (R3 = Et3, PhMe2, Ph2Me) and Me3SiCl.
10
Figure 1.4 Relative yields of the disiloxanes obtained at 50 °C from the reactions of R3SiH (R3 = Et3, PhMe2, Ph2Me) and Me3SiCl.
Clearly, these results illustrate a pattern for the yield formation of disiloxanes (and chlorosilane) products. The major and initial products in each reaction were the new chlorosilane
(R3SiCl) and Me3SiOSiMe3, followed by the mixed disiloxane (R3SiOSiMe3), and finally, slowly in minor amounts, symmetrical disiloxane (R3SiOSiR3) that comes from the starting hydrosilane. Since the initial purpose of this chemistry was the production of unsymmetrical disiloxanes, these results were disappointing. However, the predominant formation of the symmetrical disiloxane derived from the starting chlorosilane was an important discovery.
1.4.3 Reactions of Et3SiH with different chlorosilanes
In our attempt to understand this chemistry, we evaluated the possible variations in the results if we use different chlorosilanes (R3SiCl) and keep using the same hydrosilane, Et3SiH (eq. 1.8).
(1.8)
11 The results showed basically the same behavior as described above, the predominant product was the new chlorosilane (Et3SiCl), then the symmetrical siloxane which comes from the initial chlorosilane (R3SiOSiR3), the unsymmetrical disiloxane (Et3SiOSiR3) and the Et3SiOSiEt3.
In each case, the NMe3 was formed. The relative yields of the disiloxanes products were determined by 1H NMR spectroscopy are presented in Table 1.2.
Table 1.2 Relative yields of the disiloxanes and chlorosilane obtained from RT to 50 °C for the reactions of Et3SiH and R3SiCl. The last column designates the time when the starting Et3SiH is consumed.
R3 R3SiOSiR3 R3SiOSiEt3 Et3SiOSiEt3 Temp. Time 85% 15% 0 RT 6 d Me3 60% 21% 19% 50 °C 3 h Et3 100% RT 50 °C 21 h 3 h PhMe2 76% 24% 0 RT 50 °C 3 h 6 h Ph2Me 61% 23% 16% RT 50 °C 15 h 4 h Ph3 70% 26% 4% RT 50 °C 19 h 6 h
The results for the reaction of Et3SiH with Me3SiCl are from the previous study (Table 1.1), each reaction was done at room temperature and 50 °C respectively. The rest of the reactions were placed at room temperature for some hours, then raised the temperature up to 50 °C and kept the reaction mixture at that temperature for the time noted in Table 1.3, i.e. the reaction Et3SiH and Ph2MeSiCl was at room temperature during 15 hours, then at 50 °C for 4 hours until the hydrosilane was consumed.
The reaction of Et3SiH with Et3SiCl only formed one set of products, it was not studied, except for time to completion. For this reason, it was not included in the next graph to avoid discrepancies on the curve. The graph in Fig. 1.5 outlines the results displayed in Table 1.2, showing the yield formation of the products for each reaction using different chlorosilane and maintaining the same
Et3SiH. The NMR monitoring spectra for these reactions are provided in the appendix section (A 1.8-1.11). This Figure illustrates in a beautiful and clear manner, the tendency of the yield formation of disiloxanes, putting in a nutshell the behavior of this chemistry.
12
Figure 1.5 Relative yields of the disiloxanes obtained from the reactions of Et3SiH and R3SiCl (R3 = Et3, PhMe2, Ph2Me, Ph3).
More reactions of this matter were done using different chlorosilanes and hydrosilanes, the table with the results is described in the Appendix section (A 1.12-1.19).
No significant differences were found when equimolar amounts of Et3SiH, Me3SiCl and DMF were used with 5 mol% of the Mo-catalyst. As previously stated, the major and initial products are Et3SiCl and Me3SiOSiMe3, followed by Me3SiOSiEt3, and in minor amounts, the symmetrical disiloxane Et3SiOSiEt3, that comes from the starting Et3SiH, Table 1.3 (A 1.20-1.21).
Table 1.3 Relative yields of the disiloxanes formed at RT and 50 °C for the reaction of Et3SiH, Me3SiCl, DMF and Mo-catalyst (1:1:1:5%). The last column designates the time when the starting Et3SiH was consumed.
R3 Me3SiOSiMe3 Me3SiOSiR3 R3SiOSiR3 Temp. Time Et 78% 22% 0 RT 6 d 3 72% 25% 3% 50 °C 4 h
At some point, H/Cl exchange on silicon came into our minds since we were getting a new chlorosilane but there is no evidence for the formation of a new hydrosilane. Regardless of the unexpected results with respect to disiloxane and chlorosilane formation, we were able to observe
13 that the DMF was reduced to Me3N without apparent formationof the siloxymethylamine, 1. Also, there is no evidence for the formation of Eschenmoser’s salt (ClCH2NMe2) which should be formed from the reaction of 1 and chlorosilane. One idea to explain the lack of evidence of the formation of R3SiOCH2NMe2 and ClCH2NMe2 is simply that as soon as they form, they react promptly with R3SiH, thus, precluding their observation. Many ambiguities give rise into multiple suggestions regarding the mechanism of the new chemistry.
1.4.4 Hydrogen/Chloro exchange at Silicon?
To prove the transformation of the R3SiH to R3SiCl and note whether a simple and direct H/Cl exchange on silicon was taking place in this chemistry, we performed a series of reactions.
These involved mixtures of R3SiH (R3 = Et3, PhMe2, Ph2Me) and R3SiCl (R3 = Me3, PhMe2) with 5-fold excess of DMF and 5 mol% of the catalyst under different conditions outlined in Table 1.4 (eq. 1.9).
(1.9)
Table 1.4 Reactions to probe H/Cl exchange at silicon based on eq. 1.9.
Entry R3SiH R3SiCl DMF Cat. Temp. Time Products
1 Et3 Me3 + - RT 7 d Traces of R3SiCl and R3SiOSiR3. 2 Et3 Me3 - + RT 6 d N.R. 3 Et3 Me3 - - RT 6 d N.R. 4 Et3 Me3 + - 50 °C 7 d Traces of R3SiCl and R3SiOSiR3. 5 Et3 Me3 - + 50 °C 2 d N.R. 6 Et3 Me3 - - 50 °C 2 d N.R. 7 PhMe2 Me3 + - RT 11 d Traces of R3SiCl and R3SiOSiR3. 8 PhMe2 Me3 - + RT 3 d N.R. 9 PhMe2 Me3 - - RT 3 d N.R.
10 Ph2Me Me3 + - RT 3 d Traces of R3SiCl and R3SiOSiR3. 11 Ph2Me Me3 - + RT 2 d N.R. 12 Ph2Me Me3 - - RT 2 d N.R. 13 - PhMe2 + - 50 °C 3 d Traces of R3SiOSiR3. 14 - PhMe2 + + 50 °C 3 d Traces of R3SiOSiR3.
14 From the data summarized in Table 1.4, we can conclude that H/Cl exchange on silicon was not present in our system, no evidence of R3SiH was obtained and none for the formation of
R3SiCl. From those experiments, we learned that both DMF and Mo-catalyst was needed for the formation of R3SiCl. In no set-up, regardless of temperature, silicon substituent or solvent variation was there evidence for the formation of R3SiH. Entries 1, 4, 7 and 10, exhibited traces of R3SiCl or R3SiOSiR3, presumably associated with adventitious water in the DMF solvent.
1.4.5 Addition of Siloxymethylamine to the initial one-pot reaction.
Despite that our system has R3SiH in the presence of catalyst and the fact that the DMF was reduced to Me3N, we did not observe spectroscopic evidence for the formation of siloxymethylamine, as expected for the reduction of the amide under normal conditions.
Furthermore, if the siloxymethylamine was consumed by the chlorosilane as we had expected, the mixed disiloxanes R3SiOSiR3 would predominate, or at least be the initially formed disiloxane. Therefore, we had to design some experiments to evaluate the possible role of the siloxymethylamine in such a reagent mixture (eq. 1.10)
(1.10)
The one-pot reaction of R3SiH, R3SiCl, DMF, catalyst (1:1:5:5%) with the addition of 1.0
29 13 equivalent of Et3SiOCH2NMe2 was performed and monitoring by Si and C NMR spectroscopy (Fig. 1.6).
15
29 13 Figure 1.6 Si NMR (left) and C NMR monitoring of the reaction of Et3SiOCH2NMe2, Et3SiH, Me3SiCl, DMF and catalyst in C6D6 at RT for 22 hours plus another 48 hours at 50 °C (denoted in red color).
The reaction was performed at room temperature for the first 22 hours, the next 48 hours was at 50 °C. The formation of Et3SiCl, unsymmetrical disiloxane (Et3SiOSiMe3) and
Me3SiOSiMe3 was observed at 15 mins with a clear absence of Et3SiOCH2NMe2. Clearly as
“expected” the intermediate reacted instantaneously with Me3SiCl. Inspection of the NMR tube demonstrated the formation of a white solid precipitate throughout the solution region as soon as the reagents were mixed (Fig. 1.7, A).
16
Figure 1.7 Physical appearance of the NMR tube of the reaction.
The white solid remained intact at room temperature for 22 hours, while checking the NMR spectra no changes were detected. It was not until the reaction mixture was at 50 °C (2-5 hours) when changes were perceived physically and in the NMR spectra as well (Fig. 1.7, B). The solid
13 was vanishing, while the C NMR peak at 47 ppm assigned to Me3N was getting bigger (Fig. 1.6).
The Et3SiH was consumed (28 hrs. at 50 °C) and tiny amount of crystalline material was left in the NMR tube (Fig. 1.7, C). In the end, the reaction was kept for another 20 hours, but no change was observed.
Overall, the yield of the disiloxane products were obtained: Et3SiOSiEt3 (20%),
1 Et3SiOSiMe3 (69%), Me3SiOSiMe3 (11%), and were determine by H NMR spectroscopy. There is a lot to discuss from these results, first of all, this new system seemingly involved the development of three different reactions (eq. 1.11-1.13):
17 (1.11)
(1.12)
(1.13)
Apparently, the first reaction that took place was eq. 1.11, the immediate formation of the salt was noticeable in NMR tube, producing also the mixed disiloxane and resulting in the absence of Et3SiOCH2NMe2. The chemistry that we reviewed previously is denoted in eq. 1.12, where the products were expected. Since the Eschenmoser’s salt is diminishing along with the Et3SiH when
29 the reaction mixture was at 50 °C, and the peak of ~36 ppm ( Si NMR spectrum, Et3SiCl) at 5
+ - hours is increasing, which means, the [CH2NMe2] [Cl] is being reduced by the hydrosilane to produce the chlorosilane and trimethylamine (eq. 1.13). This is the first example of the reduction of an immium salt by hydrosilanes, i.e. no such chemistry is found in the literature. A related system was found in the literature using silylphosphines, instead of hydrosilanes, to form chlorosilanes and (aminomethyl)phosphines.22 This is a clear example where the hydrosilanes can be further used as reductants of immium salts. At this point, we do not know if the DMF and/or catalyst is needed for this reduction. These results also explain why the yields of the products are quite different as the chemistry seen in the previous section, where the main disiloxane formed was the one comes from the initial chlorosilane, in this case the major one is the unsymmetrical disiloxane. The Et3SiCl and Et3SiOSiMe3 are the products of two reactions, while the Me3SiOSiMe3 and Et3SiOSiEt3 are produced only by one.
1.4.6 Silane reduction of Eschenmoser’s salt
Observation of the new reduction chemistry prompted separate experiments to find the exact conditions needed to effect this reduction of the Eschenmoser’s salt by hydrosilanes (eq. 1.14).
18 (1.14)
Different reaction conditions were used to study this reduction, Table 1.5, i.e. variation of the hydrosilane with DMF or catalyst, or with both present in C6D6 as solvent. The attempts were tried at different temperatures, room temperature, 50 °C or 90 °C. No reaction took place at room temperature as implied by the previous results where the white precipitate remained unaltered at RT. However, the reaction proceeds quite smoothly with elevated temperatures.
- + Table 1.5 Results from the reduction of [Cl] [CH2NMe2] by R3SiH under different conditions. Catalyst Entry R3SiH DMF Temp. Solvent [Mo(CO)5NMe3] 1 PhMe2 + - 90 °C C6D6 2 PhMe2 - + 90 °C C6D6 3 PhMe2 + + 90 °C C6D6 4 Et3 + - 90 °C C6D6 5 Et3 - + 90 °C C6D6 6 Et3 + + 90 °C C6D6
The Eschenmoser’s salt was prepared as described in the literature from the reaction of siloxymethylamine with chlorosilane, in addition to the formation of a secondary product,
2b,21 (Et3Si)2O. After washing the salt with cold hexanes to remove the (Et3Si)2O, the hydrosilanes were added under the specific conditions outlined in Table 1.5. The reduction of the
Eschenmoser’s salt produces trimethylamine and the chlorosilane, this later on, is transformed into disiloxane, Scheme 1.4. The formation of disiloxane from the chlorosilane is explained in the next section.
19
Scheme 1.4 Reaction of the Eschenmoser’s salt with PhMe2SiH.
The reactions were followed by 29Si and 13C NMR spectroscopy, and are illustrated in Fig. 1.8 (Table 1.5, entries 1-3) and in the appendix section (A 1.22-1.24; Table 1.5, entries 4-6).
20
29 13 Figure 1.8 Si NMR (left) and C NMR monitoring of the reaction of Eschenmoser’s salt with PhMe2SiH, in C6D6 at 90 °C under different conditions described in Table 1.5: with DMF (i, entry 1), with catalyst (ii, entry 2), with DMF and catalyst (iii, entry 3).
21 The NMR spectra of these reactions show, that in the 3 cases, the formation of the
PhMe2SiCl is present as well as the Me3N, both are products of the reduction. However, in the presence of DMF and the catalyst, the reaction completed, no more hydrosilane was left, also the short reaction time is quite noticeable.
1.4.7 Chlorosilane/DMF interaction
To this point, we have collected experimental data to build a mechanism of this chemistry. Despite having demonstrated that H/Cl exchange at silicon is not taking place, there should be some kind of interaction between the chlorosilane and DMF to produce disiloxanes; the presence of catalyst and DMF is needed, but we still do not know why the mixed disiloxane was not the major product or the first one to appear, also why the R3SiOSiR3 was the disiloxane with the major yield. It has been reported by Weber23 that the interaction of DMSO and dichlorosilanes leads to the formation of siloxane derivatives and chlorodimethylsulfonium-chloride ion pair, Scheme 1.5.
Scheme 1.5 Interaction of DMSO and chlorosilanes reported by Weber.23
24 Similarly, Sun et. al. reported the activation of MeSiCl3 by DMSO as a chlorination method of enamides and enecarbamates to form a chlorosulfonium/siloxy ion pair
+ - [Me2SCl] [MeSiCl2O] . The chlorination was not successful when DMF was used instead of DMSO. In addition, Bassindale reported the interaction of halosilanes with DMF, concluding that chlorosilanes may very weakly interact with DMF to form equilibria involving
+ - 25 [Me2NCH(OSiMe3)] [Cl] . There is evidence that suggested that Si-Cl/DMF species are present
22 but unstable. Overall, chlorosilane/DMF interactions are weak but become stronger for Si-Br and Si-I/DMF mixtures. Based on the above results and observations along to the literature background, our chemistry seems to be originated by a specific chlorosilane/DMF interaction, in which iminium siloxy ion pairs are formed (Scheme 1.6).
Scheme 1.6 Interaction of DMF and chlorosilane.
In the initial resonance structure of DMF, the oxygen of the amide attacks the silyl center with loss of chloride anion. This in turn attacks imminium species to give rise to the formation of chloroimminium cation and siloxy anion. This cation moiety can be reduced by R3SiH to form
R3SiCl and the Eschenmoser’s salt. A similar reduction has been reported, using hydrosilanes to reduce nitrillium salts by Ott in 1981 (eq. 1.15).26
(1.15)
1.4.8 Reduction of the (Chloromethylene)dimethyliminium Chloride by Hydrosilane
- + The chloride salt analogous of the ion pair from Scheme 1.6, [Cl] [ClCHNMe2] , is commercially available and its synthesis is relatively straightforward.27 Thus, we attempted to react it with R3SiH and evaluate the conditions of this reduction, Table 1.6 (eq. 1.16).
23 (1.16)
- + Table 1.6 Results from the reduction of [Cl] [ClCHNMe2] by Et3SiH (eq. 1.16)
Origin of the Entry + - Catalyst Temp. Solvent Observation [ClCH2NMe2] [Cl] * C6D6, 1 Aldrich - RT N.R. CDCl3 * C6D6, 2 Aldrich - 50 °C Formation of Et3SiCl. CDCl3 Formation of Et3SiCl. Unable * C6D6, to get a good spectrum due to 3 Aldrich + RT CDCl3 the formation of solid product + - [CH2NMe2] [Cl] . * C6D6, 4 Aldrich + 50 °C Formation of Et3SiCl. CDCl3 5 in situ - RT CDCl3 Formation of Et3SiCl. Formation of Et3SiCl. The 6 in situ - 50 °C CDCl3 reaction is faster than entry 5. Formation of Et3SiCl. Unable to get a good spectrum due to 7 in situ + RT CDCl3 the formation of solid product + - [CH2NMe2] [Cl] .
The reactions started with C6D6 as a solvent, CDCl3 was added after a day of reaction due to insolubility problems of the salt, entries 1-4 (*). The results show that the reduction is taking place without the need of a catalyst when the system have a good solvent or the temperature is at
50 °C. If the catalyst is added in the system, the formation of Et3SiCl is observed as a product of the reduction, along to the precipitation of the Eschenmoser’s salt, ClCH2NMe2. The NMR spectra of these experiments are available in the appendix section (A 1.25-1.31).
1.4.9 Proposed mechanism for the one-pot reaction.
Taking everything into account, the mechanism for the in situ reaction of R3SiH, R’3SiCl and DMF in the presence of transition metal catalyst [Mo(CO)5(NMe)3], to form unsymmetrical disiloxane and ClCH2NMe2, proceeds as outlined in Scheme 1.7.
24
Scheme 1.7 Proposed mechanism for the one-pot in situ reaction to form ‘unsymmetrical disiloxanes’.
Considering all things, it seems reasonable to assume that the mechanism of reaction satisfices the results from the original reaction, and the subsequent reactions noted above. Up to this point, steps I, II and III are in equilibrium and no chemistry was observed until the silane and the catalyst participate in the reaction (step IV) to yield a new chlorosilane and the reduction of the chloroiminium cation into iminium cation and siloxy anion,26 which is our intermediate analogue (siloxymethylamine). It is well known, that siloxymethylamines can react
2b,21 with chlorosilanes (step VI) to form disiloxanes and ClCH2NMe2 (Eschenmoser’s salt). This can be reduced by silane, step VII, to form trimethylamine and chlorosilane. This type of reduction by silane is not reported in the literature, and the only related result involves silylphosphines using
25 22 polar solvents. Since we are forming a new chlorosilane (R3SiCl), this can start the cycle of the mechanism and participate in the formation of the mixed disiloxane, and then, as the concentration of R3SiCl increases, the formation of the symmetrical disiloxane (R3SiOSiR3). However, despite of the variations of hydrosilane and chlorosilane starting materials, the relative amounts of formation and time of appearance follows the same pathway: R3SiCl > R3SiOSiR3 > R3SiOSiR3 >
R3SiOSiR3. Notwithstanding the formation of Me3N, the product of the amide reduction by the hydrosilane, there is no evidence of formation of the siloxymethylamine ‘intermediate’,
R3SiOCH2NMe2.
1.4.10 Reactions involving Et3SiH and Me3SiI
After the interesting results on the hydrosilane and chlorosilane chemistry we wanted to expand this chemistry in order to understand its behavior under different conditions of both E-Cl (E = Ge and Sn) and Si-X (X = I). Thus, we studied the use iodosilane as a replacement for chlorosilane on the one-pot reaction with the same aim as previously. This reaction mixture was composed of R3SiH (1 equivalent), R3SiI (1 equivalent), DMF (5 equivalents) and Mo(CO)5NMe3
(5 mol%) in C6D6 under different temperatures (room temperature and 50 °C) in a closed system and non-aqueous environment. The reactions were monitored by NMR spectroscopy, Fig. 1.9 (A
1.32).
26
29 Figure 1.9 Si NMR monitoring of the reaction of Et3SiH, Me3SiI, DMF and catalyst in C6D6 at RT (left) and at 50 °C (right): Et3SiH = -0.04 ppm; Me3SiOSiMe3 = 7.14 ppm; Et3SiI = 41.22 ppm; Me3SiI = 41.94 ppm.
Surprisingly, evidence of a solid material in the yellowish cloudy solutions was found, slightly more precipitate in the reaction at room temperature. The reaction at room temperature did not finish after 16 days of reaction and the reagents are still present in the last NMR spectrum, while in the reaction at 50 °C, resulted in completion at the same time, without presence of starting materials. These reactions produced Et3SiI and the symmetrical disiloxane (Me3SiOSiMe3) in both cases. In addition to the formation of silicon derivatives, a peak is observed on 13C NMR spectra at 46.9 ppm which suggests us that it can be Me3N (Fig. 1.10).
27
13 Figure 1.10 C NMR monitoring of the reaction of Et3SiH, Me3SiI, DMF and catalyst in C6D6 at RT (left) and at 50 °C (right), showing the presence of Me3N at ~47 ppm.
In contrast to the previous SiH/SiCl chemistry, significant differences were found in the
SiH/SiI reaction. Firstly, there is no evidence of either Et3SiOSiMe3 or Et3SiOSiEt3, and secondly the reaction is much slower. However, overall it appears that a similar chemistry is occurring, since the disiloxane product is again, and in this case uniquely, that associated with the starting halosilane. The slow rate of the reaction can be attributed to the much weaker action of the [I]- as a nucleophile in step III of the reaction mechanism proposed above (Scheme 1.7).25
28 1.4.11 One-Pot reaction using Chlorogermane or -stannane with Et3SiH
The chemistry of Si, Ge and Sn often exhibit great similarities as well as great distinctions. Thus examination of the above chemistry using Ge and Sn chlorides was undertaken to investigate any periodicity in the system. In the case of the germanium reaction, followed by 29Si and 13C NMR spectroscopy, the complete consumption of the hydrosilane was 48 hours of reaction, which it is a shorter reaction time than the chlorosilane experiment (6 days), Fig. 1.11.
29 13 Figure 1.11 Si NMR (left) and C NMR (right) monitoring of the reaction of Et3SiH, Me3GeCl, DMF and catalyst in C6D6 at room temperature.
These results are similar to the chlorosilane reactions, producing (Et3Si)2O, Et3SiCl,
Et3SiOGeMe3, (Me3Ge)2O and Me3N. The reaction finished, when the Et3SiH is consumed, at 48 hours while in the chlorosilane version, it took 6 days for its completion. The single most conspicuous observation to emerge from the above NMR spectra was that something was formed and vanished around -4 ppm on the 13C NMR spectrum between 4 and 27 hours of reaction. No related 29Si NMR signal was observed. Apart from this discordance, the relative yield of the
29 formation of the disiloxane products were 60% for (Me3Ge)2O, while the (Et3Si)2O was formed with 26% and 14% for the Et3SiOGeMe3, respectively. This chemistry also gave the highest yield formation for the (Me3Ge)2O, which come from the initial chloroderivative, but the symmetrical disiloxane from the hydrosilane, (Et3Si)2O, was formed in higher yield than the mixed one
(Et3SiOGeMe3), which in the one-pot SiH/SiCl reaction, it was the opposite. This simple reaction has raised many questions in need of further investigation to fully understand the impact of the germanium in our initial chemistry (A 1.33). The use of trimethyltin chloride was studied, and the NMR results from monitoring such a reaction are presented in Fig. 1.12 (A 1.34).
29 13 119 Figure 1.12 Si NMR (left), C NMR (middle) and Sn NMR (left) monitoring of the reaction of Et3SiH, Me3SnCl, DMF and catalyst in C6D6 at room temperature.
Overall, reduction of the amide to form Me3N was observed with both Me3N and (Et3Si)2O being the products obtained. This implies that the Me3SnCl had zero impact upon the chemistry.
30 29 However, the formation Et3SiCl ( Si = 36.4 ppm) tells us otherwise. The reaction finished in 6 days at room temperature when the Et3SiH was consumed.
In keeping with the statement that the Me3SnCl did not impact the reduction experiment is
119 the Sn NMR monitoring which revealed the presence of the starting material, Me3SnCl, during the whole reaction time. However, a new peak appears around 0 ppm (119Sn NMR) and -9.85 ppm
13 ( C NMR), which at the beginning we thought was the formation of the (Me3Sn)2O, but appears
119 1 13 to be Me4Sn, Sn = 0 ppm; H = 0.05 ppm, C = -9.3 ppm. According to Sivasubramaniam’s
28 paper from 2006, the R3SnCl undergoes redistribution to give R2SnCl2 and R4Sn, but we do not observed any other peak at 119Sn NMR spectrum that revealed the formation of the second product
(eq. 1.17). However, the chlorination of Et3SiH must derive from some form of SnCl material, therefore a mystery is still apparent.
(1.17)
The reaction of Me3SnCl with DMF and catalyst was performed in order to see any response that can help us to understand previous results, but no change was observed after 4 days of reaction at room temperature. Thus, overall these results do not agree with the prior SiH/SiCl chemistry, delightfully illustrating distinctions between Si, Ge and Sn, a group 14 chemist’s delight. Further experiments will help to understand our findings.
31 1.5 Conclusions
Despite the fact that the one-pot reaction with hydrosilane, chlorosilane with DMF and
- + catalyst was expected to produce unsymmetrical disiloxane and [Cl] [CH2=NMe2] , the iminium salt, the actual chemistry was much more complex and led to a mixture of disiloxanes and Me3N. A mechanism of this new chemistry was proposed and each step was supported by experimental data, and illustrated for the first time, an unambiguous activation of the silicon-chlorine bond by DMF.
Changing Me3SiCl to Me3GeCl and Me3SnCl, dramatically changed the chemistry; however, to date an explanation for these new results in unclear.
1.6 Experimental
All manipulations were carried out under an argon (or nitrogen) atmosphere using Schlenk or vacuum line techniques. THF was distilled under nitrogen from benzophenone ketyl prior to use. Other solvents, hexanes, benzene and toluene were dried over sodium metal and distilled before use. Hydrosilanes, chlorosilanes, iodosilane, chlorogermane and chlorostannane were purchased either from Sigma-Aldrich or Gelest. DMF, (chloromethylene)dimethyliminium chloride and 1,4-dioxane were purchased from Sigma-Aldrich. C6D6 and CDCl3 were purchased
1 1 from Cambridge Isotope Laboratories, Inc. Et3SiOCH2NMe2, PhMe2SiOCH2NMe2,
27 29 (chloromethylene)dimethyliminium chloride and Mo(CO)5NMe3 were synthesized by the reported methods. NMR spectra were recorded on either a JEOL 600 MHz or Bruker 300 MHz spectrometer in either CDCl3 or C6D6. The crystal structures were determined using a Bruker APEX
32 CCD diffractometer with monochromatized MoKα radiation (λ = 0.71073 Å). Elemental analyses were performed by Galbraith Laboratories.
1.6.1 One-Pot reaction of hydrosilane, chlorosilane, DMF and Mo-catalyst.
In a typical experiment, a Pyrex NMR tube was charged with 1.0 equivalent of hydrosilane
(R3SiH, R3 = Et3, PhMe2, Ph2Me, Ph3), 1.0 equivalent of the R’3SiCl (R’3 = Me3, Et3, PhMe2,
Ph2Me, Ph3), 5.0 equivalents of DMF, 5 mol% of Mo(CO)5NMe3 and 0.3 mL of C6D6. The NMR tube was sealed under vacuum. The reactions were performed at room temperature or 50 °C in an oil bath. The progress of the reactions was monitored by 13C, 29Si NMR spectroscopy. The reactions were stopped when the hydrosilane was consumed. The relative yields of the disiloxanes were determine by 1H NMR spectroscopy (A 1.12, Tables 1.1-1.2).
In a typical experiment, a Pyrex NMR tube was charged with 1.0 equivalent of Et3SiH, 1.0 equivalent of the Me3SiCl, 1.0 equivalent of DMF, 5 mol% of Mo(CO)5NMe3 and 0.3 mL of C6D6. The NMR tube was sealed under vacuum. The reactions were performed at room temperature or 50 °C in an oil bath. The progress of the reactions was monitored by 13C, 29Si NMR spectroscopy. The reactions were stopped when the hydrosilane was consumed. The relative yields of the disiloxanes were determine by 1H NMR spectroscopy (Table 1.3).
1.6.2 Hydrogen/Chloro exchange at Silicon?
A Pyrex NMR tube was charged with 1.0 equivalent of hydrosilane (R3SiH, R3 = Et3,
PhMe2, Ph2Me), 1.0 equivalent of the R’3SiCl (R’3 = Me3, PhMe2), 5.0 equivalents of DMF, 5 mol% of Mo(CO)5NMe3 and 0.3 mL of C6D6. The NMR tube was sealed under vacuum. The reactions were performed at room temperature or 50 °C in an oil bath. The progress of the reactions
13 29 was monitored by C, Si NMR spectroscopy. Either no reaction was observed or traces of R3SiCl and R3SiOSiR3 were formed (Table 1.4).
33 1.6.3 Addition of Siloxymethylamine to the initial one-pot reaction.
In a typical experiment, a Pyrex NMR tube was charged with 1.0 equivalent of Et3SiH, 1.0 equivalent of the Me3SiCl, 1.0 equivalent of Et3SiOCH2NMe2, 5.0 equivalents of DMF, 5 mol% of Mo(CO)5NMe3 and 0.3 mL of C6D6. The NMR tube was sealed under vacuum. The reaction was performed at room temperature for 22 hours, the next 48 hours at 50 °C in an oil bath. The progress of the reaction was monitored by 13C, 29Si NMR spectroscopy. The reaction was stopped when the hydrosilane was consumed (Fig. 1.6).
1.6.4 Silane reduction of Eschenmoser’s salt
A Pyrex NMR tube was charged with 1.0 equivalent of hydrosilane (R3SiH, R3 = Et3,
- + 2b,21 PhMe2), 1.0 equivalent of the Eschenmoser’s salt ([Cl] [CH2NMe2] ), 5.0 equivalents of DMF,
5 mol% of Mo(CO)5NMe3 and 0.3 mL of C6D6. The NMR tube was sealed under vacuum. The reactions were performed at 90 °C in an oil bath. The progress of the reactions was monitored by 13C, 29Si NMR spectroscopy. The reactions were stopped when the hydrosilane was consumed (Table 1.5).
1.6.5 Reduction of the (Chloromethylene)dimethyliminium Chloride by Hydrosilane
In a typical experiment, a Pyrex NMR tube was charged with 1.0 equivalent of Et3SiH, 1.0
- + 27 equivalent of the [Cl] [ClCHNMe2] ), 5 mol% of Mo(CO)5NMe3 and 0.3 mL of C6D6 and/or
CDCl3. The NMR tube was sealed under vacuum. The reactions were performed at room temperature or 50 °C in an oil bath. The progress of the reactions was monitored by 13C, 29Si NMR spectroscopy. The reaction was stopped when the hydrosilane was consumed (Table 1.6).
1.6.6 Reactions involving Et3SiH and Me3SiI
A Pyrex NMR tube was charged with 1.0 equivalent of Et3SiH, 1.0 equivalent of the
Me3SiI, 5.0 equivalents of DMF, 5 mol% of Mo(CO)5NMe3 and 0.3 mL of C6D6. The NMR tube
34 was sealed under vacuum. The reactions were performed at room temperature or 50 °C in an oil bath. The progress of the reactions was monitored by 13C, 29Si NMR spectroscopy. The reactions were stopped when the hydrosilane was consumed (Fig. 1.9-10).
1.6.7 One-Pot reaction using Chlorogermane or -stannane with Et3SiH
In a typical experiment, a Pyrex NMR tube was charged with 1.0 equivalent of Et3SiH, 1.0 equivalent of the Me3ECl (E = Ge, Sn), 5.0 equivalents of DMF, 5 mol% of Mo(CO)5NMe3 and
0.3 mL of C6D6. The NMR tube was sealed under vacuum. The reactions were performed at room temperature. The progress of the reactions was monitored by 13C, 29Si NMR spectroscopy. The reactions were stopped when the hydrosilane was consumed (Fig. 1.11-12).
1.7 References
1. Arias-Ugarte, R.; Sharma, H. K.; Morris, A. L.; Pannell, K. H. J. Am. Chem. Soc. 2012, 134, 848-851. 2. a) Sharma, H. K.; Pannell, K. H. Angew. Chem. Int. Ed. Engl. 2009, 48, 7052-7054. b) Sharma,
H. K.; Arias-Ugarte, R.; Tomlinson, D.; Gappa, R.; Metta-Magaña, A. J.; Ito, H.; Pannell, K. H. Organometallics. 2013, 32, 3788-3794. 3. Miessler, G. L.; Fischer, P. J.; Tarr, D. A. Inorganic Chemistry; Fifth edition ed.; Pearson, 2014. 4. Pruchnik, F. P. Organometallic Chemistry of the Transition Elements; Plenum Press, 1990. 5. Colvin, E. Silicon in Organic Synthesis; Butterworth and Co., 1981. 6. a) Petrov, A. D.; Mironov, B. F.; Ponomarenko, V. A.; Chernyshev, E. A. Synthesis of
Organosilicon Monomers; Heywood: London, 1964. b) Rhee, S.-G.; Eisch, J. J. J. Am. Chem. Soc. 1974, 97, 4673-4682. c) Reichenbach, T.; Miller, R. B. Tetrahedron Lett. 1974, 6, 543- 546. 35 7. Constable, D. J. C.; Dunn, P. J.; Hayler, J. D.; Humphrey, G. R.; Leazer, J. J. L.; Linderman, R. J.; Lorenz, K.; Manley, J.; Pearlman, B. A.; Wells, A.; Zaks, A.; Zhang, T. Y. Green Chem. 2007, 9, 411-420. 8. Marciniec, B.; Maciejewski, H.; Pietraszuk, C.; Pawluc, P. Hydrosilylation. A comprehensive review on recent advances; Springer, 2009. 9. Constable, D. J. C.; Dunn, P. J.; Hayler, J. D.; Humphrey, G. R.; Leazer, J. J. L.; Linderman, R.
J.; Lorenz, K.; Manley, J.; Pearlman, B. A.; Wells, A.; Zaks, A.; Zhang, T. Y. Green Chem. 2007, 9, 411-420. 10. Larson, G. L. Chim. Oggi. 2013, 31, 36-39. 11. Kopylova, L. I.; Ivanova, N. D.; Voronkov, M. G. Zh. Obshch. Khim. 1985, 55, 1649. 12. a) Bézier, D.; Venkanna, G. T.; Sortais, J.-B.; Darcel, C. ChemCatChem. 2011, 3, 1747-1750. b) Das, S.; Addis, D.; Junge, K.; Beller, M. Chem. - Eur. J. 2011, 17, 12186-12192. c) Hanada,
S.; Motoyama, Y.; Nagashima, H. Tetrahedron Lett. 2006, 47, 6173-6177. d) Hanada, S.; Tsutsumi, E.; Motoyama, Y.; Nagashima, H. J. Am. Chem. Soc. 2009, 131, 15032-15040. e) Matsubara, K.; Iura, T.; Maki, T.; Nagashima, H. J. Org. Chem. 2002, 67, 44985-44988. f) Motoyama, Y.; Aoki, M.; Takaoka, N.; Aoto, R.; Nagashima, H. Chem Commun (Camb). 2009, 12, 1574-1576. g) Motoyama, Y.; Mitsui, K.; Ishida, T.; Nagashima, H. J. Am. Chem. Soc. 2005, 127, 13150-13151. h) Park, S.; Brookhart, M. J. Am. Chem. Soc. 2012, 134, 640-653. i) Sakai,
N.; Fujii, K.; Konakahara, T. Tetrahedron Lett. 2008, 49, 6873-6875. j) Selvakumar, K.; Rangareddy, K.; Harrod, J. F. Can. J. Chem. 2004, 82, 1244-1248. k) Sunada, Y.; Kawakami, H.; Imaoka, T.; Motoyama, Y.; Nagashima, H. Angew. Chem. Int. Ed. Engl. 2009, 48, 9511- 9514. l) Zhou, S.; Junge, K.; Addis, D.; Das, S.; Beller, M. Angew. Chem. Int. Ed. Engl. 2009, 48, 9507-9510. 13. Arias-Ugarte, R.; Sharma, H. K.; Morris, A. L.; Pannell, K. H. J. Am. Chem. Soc. 2012, 134,
848-851. 14. Kozyukov, V. P.; Kozyukov, V. P.; Mironov, V. F. Zh. Obshch. Khim. 1981, 52, 1386-1394. 15. Hreczycho, G. Eur. J. Inorg. Chem. 2015, 2015, 67-72. 36 16. Grubb, W. T. J. Am. Chem. Soc. 1954, 76, 3408-3414. 17. Sridhar, M.; Ramanaiah, B. C.; Narsaiah, C.; Kumara Swamy, M.; Mahesh, B.; Kumar Reddy, M. K. Tetrahedron Lett. 2009, 50, 7166-7168. 18. Michalska, Z. M. Transition Met. Chem. 1980, 5, 125-129. 19. Chojnowski, J.; Rubinsztajn, S.; Cella, J. A.; Fortuniak, W.; Cypryk, M.; Kurjata, J.; Kazmiersky, K. Organometallics. 2005, 24, 6077-6084.
20. Mitsudome, T.; Arita, S.; Mori, H.; Mizugaki, T.; Jitsukawa, K.; Kaneda, K. Angew. Chem. Int. Ed. Engl. 2008, 47, 7938-7940. 21. Kozyukov, V. P.; Kozyukov, V. P.; Mironov, V. F. Zh. Obshch. Khim. 1983, 53, 119-126. 22. Prishchenko, A. A.; Livantsov, M. V.; Novikova, O. P.; Livantsova, L. I.; Petrosyan, V. S. Heteroat. Chem. 2010, 21, 441-445. 23. Lu, P.; Paulasaari, J. K.; Weber, W. P. Organometallics. 1996, 15, 4649-4652.
24. Sun, J.; Lu, X.; Lin, D.; Cheng, K. Synlett. 2009, 2009, 2961-2964. 25. Bassindale, A. R.; Stout, T. J. Organomet. Chem. 1982, 238, C41-C45. 26. Fry, J. L.; Ott, R. A. J. Org. Chem. 1981, 46, 602-607. 27. Kimura, Y.; Matsuura, D.; Hanawa, T.; Kobayashi, Y. Tetrahedron Lett. 2012, 53, 1116-1118. 28. Davies, A. G.; Sella, A.; Sivasubramaniam, R. J. Organomet. Chem. 2006, 691, 3556-3561. 29. Maher, J. M.; Beatty, R. P.; Cooper, N. J. Organometallics. 1985, 4, 1354-1361.
37 CHAPTER 2. SILOXYMETHYLAMINE, A MASKED ANALOGUE OF ESCHENMOSER’S SALT (MANNICH REAGENT)
2.1 Abstract
Previous research has demonstrated that siloxymethylamine intermediates
R3SiOCH2NMe2, 1, are the initial products in the reduction of amides by hydrosilanes catalyzed by Mo-catalyst and be readily isolated and studied.1 In the catalytic process, it was shown that these intermediates reacted further with R3SiH species to form disiloxanes and trimethylamine.
- + This led us to formulate 1 as a transient siloxy-imminium ion pair [R3SiO] [CH2NMe2] and further suggested that these intermediates could be suitable Mannich reagents, methyldimethylamino [CH2NMe2] transfer agents with element-hydrogen bonds polarized in the manner R’Eδ--Hδ+.2 This chapter illustrates our use of these materials in reactions with O-H and S-
H bonds to form R’OCH2NMe2 and R’SCH2NMe2, respectively. Furthermore, when R’ in the starting R’OH is an aromatic group, CH2NMe2 transfer to the aromatic ring has been observed rather than O-H substitution.
2.2 Research Objectives
δ+ δ- Preliminary work showed the reaction of 1 with silanes (R3SiH, R3Si -H ) and
δ+ δ- chlorosilanes (R’3SiCl, R’3Si -Cl ), formed disiloxanes R3SiOSiR’3 and HCH2NMe2 (Me3N), and
ClCH2NMe2, respectively. We suggested that 1 can act as a masked analogue of Eschenmoser’s salt, acting as a methyldimethylamino transfer agent, Mannich reagent. This suggestion offers
38 reactions with element hydrogen bonds polarized in the opposite manner, R’Eδ+-Hδ-, to yield new materials, R’ECH2NMe2 plus the formation of the corresponding silanol. This chapter presents the reactions between 1 and compounds with a series of E-H bonds
(E = O, S, N) which prove its utility and reliability as a new [CH2NMe2] transfer reagent.
2.3 Introduction
The first study on siloxymethylamine derivatives, Me3SiOCH2NMe2, was performed in 1982 by Mironov group, obtained as the product from the condensation reaction of
3 trimethylsilylamine, Me3SNMe2 and formaldehyde. Our more recent discovery that they are readily obtained in high yield from the Mo-catalyzed addition of silanes to DMF makes them a more attractive reagent (eq. 2.1).1
(2.1)
In the same manner, the readily available tetramethyldisiloxane (TMDS) has been used as a reductant of amides,4 specifically DMF, and also produces the bis-siloxymethylamine intermediate (Me2NCH2OSiMe2OSiMe2OCH2NMe2) which can also be isolated in high yield (eq. 2.2).5
(2.2)
39 As noted above both the Mironov group6 and ourselves5 have demonstrated the capacity of
δ+ δ- these intermediates to react with chlorosilanes, -germanes and -stannanes (R’3E -Cl , E = Si, Ge,
Sn) to form the corresponding ClCH2NMe2 and R3SiOER3. Therefore, this opportunity suggests that 1 can act as a Mannich reagent, a methyldimethylamino [CH2NMe2] transfer agent in the proper environment, acting as a transcient siloxy-imminium ion pair (eq. 2.3).
(2.3)
That idea suggests that reactions with element hydrogen bonds polarized in the opposite manner R’Eδ--Hδ+, may react with siloxymethylamine intermediates, 1, to yield new materials
(R’ECH2NMe2, 2-3) and the formation of the correspondent silanol (eq. 2.4).
(2.4)
In the case of the aminoethers, 2, hemiaminals, they have many applications, for instance, they are used as starting materials along with chlorosilanes for the preparation of iminium salts
(eq. 2.5).7
(2.5)
Since the product of equation 2.5, Eschenmoser’s salt, also serves as an in situ aminomethylation reaction without isolation of the iminium salt, an advantage that avoids the time- consuming procedure and the inconvenient manipulation of the salt due to its hygroscopic nature.8 These Mannich reagents are used in the aminomethylation of phosphonites,9 acetylenes,10
40 lactones,11 many heterocycles,11-12 etc. Hemiaminal derivatives are prepared by different methods,13 one of them is from chloro ethers and secondary amines,14 or from diamine and thiols.15 The classic Mannich aminomethylation involves the condensation of a substrate R-H, in our chemistry R’EH, E = O, S, N, etc., possessing at least one active hydrogen including phenols, NH-hetrocycles, thiols, etc., with formaldehyde or another aldehyde, and a primary or secondary amine (eq. 2.6).16
(2.6)
Thus, any success in using 1 as a dimethylaminomethyl transfer agent will provide an excellent one-pot, one reagent process. My work mainly focused upon use of Et3SiOCH2NMe2 unless specifically noted otherwise.
2.4 Results and Discussion
Reactions of Et3SiOCH2NMe2, 1, with R’EH (E = O, S, N) readily led to the formation of
R’ECH2NMe2 derivatives and triethylsilanol, Et3SiOH. The conditions used to perform these reactions are green and quite simple, it does not require catalyst, solvent, high temperature or long reaction times. Experimentally, the reactions involved mixing 1.1 equivalents of 1 and 1.0 equivalent of R’EH, in C6D6 to permit NMR monitoring, followed by distillation, or in case of solid products, simply washing with cold hexanes and recrystallization.
41 2.4.1 Reactions of Et3SiOCH2NMe2 with Aliphatic Alcohols
Our initial investigations involved the reactions of 1.0 equivalent of aliphatic alcohols and 1.1 equivalents of siloxymethylamine. The reactions were essentially instantaneous to form
R’OCH2NMe2 and triethylsilanol (eq. 2.7).
(2.7)
17 12c The alkoxymethylamine derivatives MeOCH2NMe2 (2a), EtOCH2NMe2 (2b), i 12c t PrOCH2NMe2 (2c), were obtain in good yields, except for BuOCH2NMe2 (2d). The formation of 2d required a longer time period and higher reaction conditions that led to a certain amount of decomposition of 1 and, as observed by NMR spectroscopic analysis starting material contaminated the product. The NMR spectra of the products can be seen in the Appendix section (A 2.1-2.3). An alternative siloxymethylamine intermediate was used to investigate if the same result will be obtained. The synthesis and isolation of the bis-siloxymethylamine intermediate was
5 reported by Sharma et al in 2013. This intermediate (Me2NCH2OMe2Si)2O (1e) is the product of the reduction of DMF by (HMe2Si)2O in the presence of Mo-catalyst. The reaction of 1.0 equivalent of 1e and 1.9 equivalents of MeOH and EtOH is illustrated in eq. 2.8.
(2.8)
The 13C NMR spectra of the reactions products exhibit the same chemical shift for the
R’OCH2NMe2 products compared with the reactions done with intermediate 1a from eq. 2.7. We 42 made no attempt to isolate the products from this approach; however, the NMR spectra are available in the Appendix section (A 2.1, Fig. A.54; A 2.2, Fig. A.57). This analysis exemplifies the versatility of these siloxymethylamine intermediates as [CH2NMe2] transfer agents.
2.4.2 Reactions of Et3SiOCH2NMe2 with Aromatic Alcohols
The reactions of 1.1 equivalents of 1a with 1.0 equivalent of aromatic alcohols afforded the formation of the products 2e-f via aromatic electrophilic substitution with regiospecificity and leaving the OH group intact, Scheme 2.1.
Scheme 2.1 Reaction of 1a with aromatic alcohols.
The aminomethylation on phenol give rise to the formation of derivative 2e,18 along with the formation of triethylsilanol (A 2.4). This reaction has excellent ortho-selectivity towards phenol. If both ortho-positions are blocked by methyl groups, the aminomethylation occurs at the para-position illustrated in derivative 2f (A 2.5).18c,19 The single X-Ray crystal structure of derivative 2f was obtained, as can be seen from Fig. 2.1, the N atrom is significally out of the plane of the aromatic ring, with a dihedral angle of 80°.
43
Figure 2.1 Structure of 2,6-dimethyl-4-dimethylaminomethyl phenol, 2f.
The derivative 2,6-dimethyl-4-dimethylaminomethyl phenol (2f) was obtained with 78% yield, and the 13C NMR spectrum is shown in Fig. 2.2.
13 Figure 2.2 C NMR spectrum of 2f in CDCl3: 16.12 (Me), 45.25 (N(Me)2), 63.91 (CH2), 123.65, 129.58, 129.85, 151.72 ppm (Ph).
Taking as a background the unpublished results from our research group, the reaction of 1a with 1-naphthol and 2-naphthol in equimolar amounts, give the formation of the following products, respectively, it is outline in Fig. 2.3.
44
Figure 2.3 Structures of the 2-[(dimethylamino)methyl]-1- naphthalenol, 2g (left), and 1-[(dimethylamino)methyl]- 2-naphthalenol, 2h (right), derivatives.
If a different ratio or a different siloxymethylamine is used, double aminomethylation in the naphthol arises, Scheme 2.2.
Scheme 2.2 Reactions 1a or 1c with 1-naphthol to form derivative 2i.
As can be seen above, the double substituted naphthol derivative 2i20 was obtained by 2 different reactions: the treatment of a) 2.1 equivalents of 1a with 1.0 equivalent of 1-naphthol, and b) 1.01 equivalents of 1e with 1.0 equivalent of 1-naphthol. The product was isolated from treatment ‘a)’, obtaining 73% yield of 2i, its single X-Ray crystal structure is illustrated in Fig. 2.4.
45
Figure 2.4 Single X-Ray crystal structure of 2,4-bis[(dimethylamino)methyl]-1-naphthalenol, 2i.
The reaction was monitored by NMR spectroscopy, and it is illustrated in Fig. 2.5. This highlights that the double substitution is quite fast because the reaction was almost complete in 15 minutes, and the chemical shift of 2i was present without evidence of 2g.
46
Figure 2.5 NMR monitoring of the formation of 2i.
At the time of the first NMR spectrum at 15 minutes, the peaks of the double aminomethylation in the naphthol were observed. At 10 hours of reaction we can observed that the siloxymethylamine was present, but it was in excess. The last NMR spectrum shows peaks for the isolated compound after recrystallization with cold hexanes to remove the silanol (A 2.6).
47 The NMR spectra of the crude mixture from reaction ‘b)’ were compared with ‘a)’ showing the same chemical shifts of 2i plus the presence of the (OHMe2Si)2O, the subproduct (A 2.6, Fig. A.68). We tried to isolate the product from the silanol, but it was not simple. The silanol was transformed into a polymer derivative complicating the separation. The reaction of 1a with 2-naphthol was done as well, using the same ratio (2.1:1) in order to see the double substitution like in 1-naphthol. After 10 hrs of reaction we only observed the formation of the mono substituted derivative 2h (A 2.7). The reaction might need higher temperature or longer reaction times to form the double substituted naphthol derivative.
2.4.3 Reactions of Et3SiOCH2NMe2 with Cholesterol
The interesting reaction between the cholesterol and Et3SiOCH2NMe2 produced derivative
2j and Et3SiOH as secondary product. The dimethylaminomethyl-cholesterol derivative, 2j, is an unknown material, and its structure is illustrated in Figure 2.6.
Figure 2.6 Structure of cholesteromethyl(dimethyl)amine, 2j.*
The cholesterol core remains intact while the substitution takes place only on the OH group in the cholesterol. There are several derivatives of cholesterol reported in the literature involving
*The crystals of 2j were obtained in collaboration with Dr. Sanchita Chakrabarty. 48 modification of the core and aliphatic chain. These are interesting materials for the modification of bioavailability and as a potential regulators of cholesterol metabolism.21 However, the methylamine derivative (2j) has not been reported (A 2.8).
2.4.4 Reactions of Et3SiOCH2NMe2 with Aliphatic Thiols
The treatment of 1.0 equivalent of aliphatic thiols and 1.1 equivalents of siloxymethylamine intermediates at room temperature is shown in Table 2.1 (eq. 2.9).
(2.9)
Table 2.1 Reaction of aliphatic thiols and siloxymethylamine intermediates, eq. 2.9.
Entry R3 R’3SH Product
1 Et3 EtSH 3a 2 Et3 PrSH 3b 3 PhMe2 PrSH 3b 4 Et3 BuSH 3c 5 PhMe2 BuSH 3c
These reactions displayed similar chemistry as observed for the reactions with aliphatic alcohols. The reactions are instantaneous at room temperature, and solvent or catalyst are not required. The derivative 3a22 was obtained as shows in Table 2.1, entry 1; with 63% yield, and it was separated from the silanol by distillation at 44-45 °C/25 mm Hg, Fig. 2.7.
49
13 Figure 2.7 C NMR spectrum of EtSCH2NMe2, 3a.
When 1a was used, entries 2 and 4 of Table 2.1, to react with PrSH and BuSH, respectively; the reactions take place and the products were formed, but after distillation, the silanol was still present in both samples because the boiling point of the silanol and the derivatives 3b-c are pretty close. For those cases, we had to change the siloxymethylamine intermediate in order to have a bigger range on the boiling points of the silanol and the products. The treatment of
15 PhMe2SiOCH2NMe2 with PrSH and BuSH yield to the formation of 3b and 3c , respectively. The silanol was successfully removed from the products by distillation. The derivative 3b,
PrSCH2NMe2, is unknown. The NMR spectra of derivatives 3b-c are illustrated in the Appendix section (A 2.9-2.11).
2.4.5 Reactions of Et3SiOCH2NMe2 with Aromatic Thiols
The reaction of 1 with aromatic thiols results only in the formation aminothio derivatives,
R’SCH2NMe2. Thus, the aromatic thiols behave like the aliphatic thiols with no evidence for electrophilic substitution on the aromatic rings as was observed for the aromatic alcohols, Scheme 2.3.15
50
Scheme 2.3 Reactions of 1a and aromatic thiols.
Derivative 3d was obtained with 79% yield, and no substitution was observed on the ring
(A 2.12). The unknown compound 3e was obtained from the reaction of Et3SiOCH2NMe2 and 2,6-
Me2C6H3-1-SH and isolated from the Et3SiOH, Fig. 2.8 (A 2.13).
Figure 2.8 13C NMR spectrum of derivative 3e.
51 Leaving this compound on the bench, results in decomposition, forming an S-S bonded material with loss of the [CH2NMe2] group. This fact was confirmed by X-ray crystallography, Fig. 2.9.
Figure 2.9 Decomposition of 3e, formation of S-S bond.
2.5 Conclusions
It has been proposed and demonstrated that siloxymethylamine intermediates have the
- + capacity to act as a transcient siloxy-imminium ion pair [R3SiO] [CH2NMe2] , which it is analogous to an Eschenmoser’s salt. As a consequence, 1 acts as a Mannich reagent, a methyldimethylamino [CH2NMe2] transfer agent, reacting with aliphatic alcohols (R’OH) and thiols (R’SH), including cholesterol affording the formation of aminoethers and -thiols. In the case of R’ = aromatic, electrophilic substitution on the aromatic ring occurs in the case of the alcohols, phenol, naphthol to form ortho and/or para dimethylaminomethyl derivatives, leaving the OH group unreacted. This latter chemistry does not occur with the aromatic thiols. We have found a new application for these siloxymethylamine materials as Mannich reagents, thereby providing a powerful methodology for the synthesis of hemiaminals without catalyst, solvents or elevated temperatures.
52 2.6 Experimental
All manipulations were carried out under an argon (or nitrogen) atmosphere using Schlenk or vacuum line techniques. THF was distilled under nitrogen from benzophenone ketyl prior to use. Other solvents, hexanes, benzene and toluene were dried over sodium metal and distilled
1 before use. All alcohols and thiols were purchased from Sigma-Aldrich. Et3SiOCH2NMe2 ,
1 5 PhMe2SiOCH2NMe2 , and (Me2NCH2OMe2Si)2O were synthesized by the reported methods. NMR spectra were recorded on either a JEOL 600 MHz or Bruker 300 MHz spectrometer in either
CDCl3 or C6D6. The crystal structures were determined using a Bruker APEX CCD diffractometer with monochromatized MoKα radiation (λ = 0.71073 Å). Elemental analyses were performed by
Galbraith Laboratories.
2.6.1 Reactions of Et3SiOCH2NMe2 with Alcohols and thiols, 2-3.
In a typical experiment, a Pyrex NMR tube or 15-mL round-bottom flask was charged with
1.1 equivalents of 1, 1.0 equivalent of the R’EH (E = O, R’ = Me, Et, t-Bu, Ph, 2,6-Me2C6H3, cholesterol; E = S, R’ = Et, 1-Pr, 1-Bu, Ph, 2,6-Me2Ph) and 0.5 mL of C6D6 or CDCl3 and sealed under vacuum or under inert atmosphere. The reactions were performed at room temperature and progress was monitored by 13C, 29Si NMR spectroscopy; however, the formation of the products was essentially instantaneous. The products were purified by distillation or in the case of the solid one, simply washed with cold hexanes and recrystallized.
o 1 MeO-CH2NMe2, 2a: yield 53%, b.p. 25 C/30 mm Hg. H NMR (C6D6, 300 MHz): δ 2.31 (s, 6
13 H, (CH3)2N), 3.15 (s, 3 H, Me), 3.85 (CH2). C NMR (C6D6, 300 MHz): δ 41.50 ((CH3)2N), 55.57
17 o 1 (Me), 90.82 (CH2). Reported : yield 33%, b.p. 63 C. H NMR (CDCl3, 400 MHz): δ 2.4 (s, 6 H,
Me2N), 3.35 (s, 3 H, MeO), 3.97 (s, 2 H, NCH2O) ppm.
53 o 1 EtO-CH2NMe2, 2b: Yield: 62%, b.p. 30 C/25 mm Hg. H NMR (C6D6, 300 MHz): δ 1.52 (t, 3
13 H, -CH2CH3), 2.68 (s, 6 H, (CH3)2N), 3.82 (q, 2 H, -CH2CH3), 4.31 (CH2). C NMR (C6D6, 300
12c 1 MHz): δ 15.11, 63.43 (Et), 41.23 ((CH3)2N), 89.09 (CH2). Reported : yield 15%, b.p. 95 °C. H
NMR (CDCl3, 60 MHz): δ 1.23 (t, 3 H, OCH2CH3), 2.30 (s, 6 H, NCH3), 3.43 (q, 2 H, OCH2CH3),
4.13 (s, 2 H, NCH2O) ppm.
i 1 PrO-CH2NMe2, 2c: Yield 67%, b.p. 24 °C/30 mm Hg. H NMR (C6D6, 300 MHz): δ 1.04 (d, 6
13 H, CH(CH3)2), 2.23 (s, 6 H, (CH3)2N), 3.52 (sept, 1 H, CHMe2), 3.89 (s, 2 H, NCH2O) ppm. C
NMR (C6D6, 300 MHz): δ 22.51 (CH(CH3)2), 41.48 ((CH3)2N), 69.15 (CHMe2), 87.32 (NCH2O)
12c 1 ppm.. Reported : yield 15%, b.p. 98-101°C. H NMR (CDCl3, 60 MHz): δ 1.17 (d, 6 H,
13 CH(CH3)2), 2.33 (s, 6 H, (CH3)2N), 3.37-3.97 (sept, 1 H, CHMe2), 4.03 (s, 2 H, NCH2O) ppm. C
NMR (CDCl3, 20 MHz)): δ 22.5 (CH(CH3)2), 41.6 ((CH3)2N), 69.6 (CHMe2), 87.4 (NCH2O) ppm.
1 2-((dimethylamino)methyl)phenol, 2e: Yield: 51%, b.p. 75 °C/3 mm Hg. H NMR (CDCl3, 300
MHz): δ 2.26 (s, 6 H, (CH3)2N), 3.58 (s, 2 H, CH2), 6.75 (t, 1 H, C-4), 6.83 (d, 1 H, C-6), 6.93 (d,
13 1 H, C-3), 7.15 (t, 1 H, C-5), 11.00 (s, 1 H, OH). C NMR (CDCl3, 300 MHz): δ 44.13 ((CH3)2N),
18 62.6 (CH2), 115.79, 118.71, 121.75, 128.12, 128.48, 157.96 (Ph). Reported : Yield: 47%, b.p.
60°C/5mmHg; δH (60 MHz) 2.27 (6H, s, NCH3), 3.55 (2H, s, CH2N), 6.67-7.30 (4H, m, PhH) and
10.47 (1H, s, D20 ex. OH) ppm; δC (20.1 MHz) 42.2 (q, NCH3), 62.7 (t, CH2N), 116.1 (d, C-6), 119.1 (d, C-4), 128.4 (s, C-2), 128.8 (d, C-5), 129.6 (d, C-3), and 158.2 (s, C-l) ppm; (m/z); 151
+ + (M , 100%), M measured 151.0989; Calc. for C9H13NO 151.0997.
4-((dimethylamino)methyl)-2,6-dimethylphenol, 2f: Yield 78%, m.p. 116-117 °C, colorless
1 crystals. H NMR (CDCl3, 600 MHz): δ 2.17 (s, 6 H, Me2), 2.21 (s, 6 H, (CH3)2N), 3.29 (s, 2 H,
13 CH2), 6.87 (s, 2 H, Ph). C NMR (CDCl3, 600 MHz): δ 16.13 (Me2), 45.25 ((CH3)2N), 63.90
18c,19 (CH2), 123.65, 129.58, 129.85, 151.72 (Ph). Reported : yield 86%, m.p. 115-117 °C, colorless
54 1 crystals. H NMR (CDCl3): δ 1.20 (s, 6 H, Me2), 1.22 (s, 6 H, (CH3)2N), 3.31 (s, 2 H, CH2), 4.97 (br s, 1 H, OH), 6.90 (s, 2 H, Ph).
1 EtSCH2NMe2, 3a: Yield: 67%, b.p. 44-45 °C/25 mm Hg. H NMR (C6D6, 300 MHz): 1.66 (t, 3
13 H, -CH2CH3), 2.68 (s, 6 H, (CH3)2N), 3.03 (q, 2 H, -CH2CH3), 4.27 (CH2). C NMR (C6D6, 300
22 MHz): δ 16.05, 27.61 (Et), 43.20 ((CH3)2N), 64.52 (CH2). Reported : b.p. 133-146 °C.
1 PrSCH2NMe2, 3b: Yield: 75%, b.p. 48-50 °C/20 mm Hg. H NMR (C6D6, 300 MHz): δ 1.37 (t, 3
H, -CH2CH2CH3), 2.00 (sext, 2 H, -CH2CH2CH3), 2.64 (s, 6 H, (CH3)2N), 2.93 (t, 2 H, -
13 CH2CH2CH3), 4.24 (s, 2 H, CH2). C NMR (C6D6, 300 MHz): δ 13.95, 24.42, 35.95 (Pr), 43.14
((CH3)2N), 64.97 (CH2).
1 BuSCH2NMe2, 3c: Yield: 80%, b.p. 34-35 °C/3 mm Hg. H NMR (C6D6, 300 MHz): δ 1.29 (t, 3
H, -CH2CH2CH2CH3), 1.79 (sext, 2 H, -CH2CH2CH2CH3), 1.93 (quint, 2 H, -CH2CH2CH2CH3),
13 2.63 (s, 6 H, (CH3)2N), 2.93 (t, 2 H, -CH2CH2CH2CH3), 4.22 (s, 2 H, CH2). C NMR (C6D6, 300
MHz): δ 14.18, 22.60, 33.27, 33.53 (Bu), 43.13 ((CH3)2N), 64.93 (CH2). HRMS (DART), Calcd.
15 –1 for C7H18NS, M+1, 148.11599, Found 148.1143. Reported : IR spectrum, cm : 2958–2780,
1 1667, 1453, 1257, 1151, 1042, 786, 646. Н NMR spectrum, δ, ppm: 0.69 m (3Н, СН3), 1.16 m
13 (2Н, СН2), 1.36 m (2Н, СН2), 1.99 br.s (6Н, СН3), 2.36 m (2Н, СН2), 3.67 br.s (2Н, СН2). С NMR spectrum, δ, ppm: 13.42 s (C7), 21.75 s (C6), 32.38 s (C5), 33.05 s (C4), 42.32 s (C8,8′), 64.32
2 + + + s (С ). Mass spectrum, m/z (Irel, %): 147 (100) [M] , 90 [M – (CH3)2NCH2 + H] , 58 [M – С4Н9S] .
Found, %: С 56.73; Н 11.44; N 9.60; S 22.23. С7Н17NS. Calculated, %: С 57.08; Н 11.63; N 9.51; S 21.77. M 147.283.
N,N-dimethyl-1-(phenylthio)methanamine, 3d: Yield: 79%, b.p. 97 °C/3 mm Hg. 1H NMR
(CDCl3, 300 MHz): δ 2.32 (s, 6 H, (Me)2N), 4.52 (s, 2 H, CH2), 7.17 (t, 1 H, CH), 7.26 (t, 2 H,
13 CH), 7.55 (d, 2 H, CH). C NMR (CDCl3, 300 MHz): δ 40.02 ((Me)2N), 68.21 (CH2), 125.73, 55 128.38, 131.14, 137.93 (Ph). Reported15: Yield: 88-90%. IR spectrum, cm–1: 3071, 2973–2786,
1 1681, 1583, 1477–1437, 1254, 1127, 1046, 959, 742, 691, 622. H NMR (CDCl3, 400 MHz): δ
2.34 br.s (6Н, СН3), 4.50 br.s (2 Н, СН2), 7.29 t (3Н, СH, J 7.2 Hz), 7.51 d (2Н, СH, J 7.2 Hz).
13 10,11 2 7 6,8 C NMR (CDCl3, 400 MHz): δ 42.71 s (C ), 69.01 s (C ), 126.37 s (C ), 128.94 s (C ), 131.75
5,9 4 + + s (C ), 138.17 s (C ). Mass spectrum, m/z (Irel, %): 167 (20) [M] , 91 (25) [M – Ph + H] , 58 (100)
+ [M – PhS + H] . Found, %: С 64.52; Н 7.95; N 8.27; S 19.26. С9H13NS. Calculated, %: С 64.62; Н 7.83; N 8.37; S 19.17. M 167.272.
1-((2,6-dimethylphenyl)thio)-N,N-dimethylmethanamine, 3e: Yield: 74%, b.p. 105-108 °C/3
1 mm Hg. H NMR (CDCl3, 600 MHz): δ 2.39 (s, 6 H, (CH3)2N), 2.65 (s, 6 H, Me2), 4.30 (s, 2 H,
13 CH2), 7.11 (s, 3 H, Ph). C NMR (CDCl3, 600 MHz): δ 22.36 (Me), 42.63 ((Me)2N), 69.34 (CH2),
127.60, 128.30, 135.89, 142.18 (Ph). HRMS (DART), Calcd. for C11H18NS, M+1, 196.11599, Found 196.1193.
2.6.2 Reactions of Et3SiOCH2NMe2 with Cholesterol to form 2j.
In a typical experiment, a 15-mL round-bottom flask was charged with cholesterol (0.85 equivalents, 4.49 mmol) dissolved in 2 mL of benzene, and 1a (1.0 equivalent, 5.28 mmol) under inert atmosphere at room temperature. The reaction was monitoring by NMR spectroscopy using
C6D6 or CDCl3 as solvent and once the reaction finished, the benzene was evaporated, the solid was washed with cold hexanes and recrystallized to yield the product.
Cholesteromethyl(dimethyl)amine, 2j: yield: 73%, m.p. 103-105 °C, white crystals. 13C NMR
(CDCl3, 300 MHz): δ 12.07, 19.03, 13.54, 21.44, 22.76, 23.00, 24.34, 24.60, 28.39, 28.62, 29.33, 32.23, 32.38, 36.20, 36.67, 37.13, 37.72, 39.92, 40.16, 40.20, 41.68, 42.60, 50.67, 56.56, 57.03, 77.12, 87.46, 121.55, 141.39 ppm.
56 2.6.3 Reactions of Et3SiOCH2NMe2 with 1- and 2-naphthol
In a typical experiment, a 15-mL round-bottom flask was charged with: a) 1-naphthol or 2-naphthol (1.0 equivalent, 0.35 mmol) dissolved in 2 mL of benzene, and 1a (2.1 equivalents, 0.73 mmol) under inert atmosphere at room temperature; b) 1-naphthol (1.0 equivalent, 6.95 mmol) dissolved in 2 mL of benzene, and 1c (1.01 equivalents, 7.02 mmol). The reaction was monitoring by NMR spectroscopy using C6D6 or CDCl3 as solvent and once the reaction finished, the benzene was evaporated, the solid was washed with cold hexanes and recrystallized to yield the formation of the product. The reaction was monitoring by NMR spectroscopy using C6D6 or
CDCl3 as solvent.
2,4-bis[(dimethylamino)methyl]-1-naphthalenol, 2i: yield: 73%, m.p. 75-77 °C. 1H NMR
(CDCl3, 600 MHz): δ 2.28 (s, 6 H, (Me)2N), 2.37 (s, 6 H, (Me)2N), 3.71 (s, 2 H, CH2), 3.77 (s, 2
H, CH2), 6.99 (s, 1 H, aromat. H), 7.43-7.46 (t, 1 H, aromat. H), 7.48-7.50 (t, 1 H, aromat. H),
13 8.11-8.12 (d, 1 H, aromat. H), 8.26-8.27 (d, 1 H, aromat. H) ppm. C NMR (CDCl3, 600 MHz): δ
44.65 ((Me)2N), 45.60 ((Me)2N), 61.99 (CH2), 63.02 (CH2), 113.30, 122.44, 124.05, 124.64, 125.37, 126.19, 128.18, 132.77, 153.55 (aromat.) ppm. Reported20: yield 37%. 1H NMR (DMSO- d6): δ 8.09 (s, 1 H, OH), 7.99-8.25 (m, 2 H, aromat. H), 7.37-7.53 (m, 2 H, aromat. H), 7.07 (s, 1
H, aromat. H), 3.78 (s, 2 H, CH2N), 3.65 (s, 2 H, CH2N), 2.31 (s, 6 H, CH3NCH3), 2.16 (s, 6 H,
CH3NCH3).
Dr. Sanchita Chakrabarty’s work: 2-((dimethylamino)methyl)naphthalen-1-ol, 2g:20 1-Naphthol (0.3 g, 2.08 mmol) and 1a (0.4 g, 2.1 mmol) were dissolved in 2 mL of benzene. After 10 minutes the solvent was removed under vacuum, and the residue was passed passed through a small silica gel column. The column was eluded with hexane followed by (1:2) hexane-THF mixture. The final yield of the product was
13 57%. NMR, C (CDCl3) 44.64 (NMe2), 63.16 (CH2-N), 114.35, 118.23, 122.18, 124.91, 125.12,
57 126.05, 126.49, 127.44, 134.07, 153.94; 1H, 1.8 (s, 6H), 3.3 (s, 2H), 6.9-7.9 (Ar-H, complex, 6H), 8.9 (1H).
1-((dimethylamino)methyl)naphthalen-2-ol, 2h:18a,18c 2-Naphthol (0.3 g, 2.08 mmol) and 1a (0.4 g, 2.1 mmol) were dissolved in 2 mL of benzene. After 10 minutes the solvent was removed under vacuum and the residual oil was dissolved in small amount of hexane and left at 5 ºC overnight. The yellow-brown crystals formed were washed with cold hexane to remove any
13 residual silanol. The final yield of the product was 63%. M.pt. 71-72 ºC; NMR, C (C6D6) 44.04
1 (NMe2), 57.79 (CH2-N), 111.7, 119.8, 121.2, 122.4, 126.4, 129.0, 129.3, 129.6, 133.3, 157.7; H, 1.9 (s, 6H), 3.7 (s, 2H), 7.3-7.9 (Ar-H, complex, 6H), 12.1 (s, 1H).
2.7 References
1. Arias-Ugarte, R.; Sharma, H. K.; Morris, A. L.; Pannell, K. H. J. Am. Chem. Soc. 2012, 134, 848-851. 2. Sharma, H. K.; Gonzalez, P. E.; Craig, A. L.; Chakrabarty, S.; Metta-Magana, A.; Pannell, K.
H. Chemistry. 2016, 22, 7363-7366.
3. Kozyukov, V. P.; Kozyukov, V. P.; Mironov, V. F. Zh. Obshch. Khim. 1982, 52, 1386-1394. 4. Larson, G. Chimica Oggi. 2013, 31, 36-39. 5. Sharma, H. K.; Arias-Ugarte, R.; Tomlinson, D.; Gappa, R.; Metta-Magaña, A. J.; Ito, H.; Pannell, K. H. Organometallics. 2013, 32, 3788-3794. 6. Kozyukov, V. P.; Kozyukov, V. P.; Mironov, V. F. Zh. Obshch. Khim. 1983, 53, 119-126.
7. Rochin, C.; Babot, O.; Dunogues, J.; Duboudin, F. Synthesis. 1986, 3, 228. 8. Hosomi, A.; Iijima, S.; Sakurai, H. Tetrahedron Lett. 1982, 23, 547-550.
58 9. a) Badeeva, E. K.; Krokhina, S. S.; Ivanov, B. E. Zh. Obshch. Khim. 2003, 73, 1455-1459. b) Prishchenko, A. A.; Livantsov, M. V.; Novikova, O. P.; Livantsova, L. I.; Petrosyan, V. S. Heteroat. Chem. 2010, 21, 361-367. c) Prishchenko, A. A.; Livantsov, M. V.; Novikova, O. P.; Livantsova, L. I.; Petrosyan, V. S. Heteroat. Chem. 2010, 21, 441-445. d) Prishchenko, A. A.; Livantsov, M. V.; Novikova, O. P.; Livantsova, L. I.; Petrosyan, V. S. Heteroat. Chem. 2010, 21, 515-520.
10. Gevorkyan, A. A.; Movsisyan, A. A.; Dzhandzhulyan, Z. L.; Arakelyan, A. S.; Petrosyan, K. A. Russ. J. Gen. Chem. 2008, 78, 504-505. 11. Oida, T.; Tanimoto, S.; Ikehira, H.; Okano, M. Bull. Chem. Soc. Jpn. 1983, 56, 645-646. 12. a) Yakhontov, L. N.; Azimov, V. A. Khimiya Geterotsiklicheskikh Soedinenii. 1970, 6, 32-36. b) Heaney, H.; Papageorgiou, G.; Wilkins, R. F. J. Chem. Soc., Chem. Commun. 1988, 1161- 1163. c) Heaney, H.; Papageorgiou, G.; Wilkins, R. F. Tetrahedron. 1997, 53, 2941-2958.
13. Mcleod, C. M.; Robinson, G. M. Journal of the chemical Society, Transactions. 1921, 119, 1470-1476. 14. Chambon, M.; Girardet, L.; Boucherie, A. Bull. Soc. Chim. Fr. 1954, 1060-1065. 15. Khairullina, R. R.; Akmanov, B. F.; Tyumkina, T. V.; Kunakova, R. V.; Ibragimov, A. G. Russ. J. Org. Chem. 2012, 48, 175-179. 16. Tehrani, K. A.; De Kimpe, N. In Science of Synthesis: Houben-Weyl Methods of Molecular
Transformations; Padwa, A., Al, E., Eds. 2005; Vol. 27. 17. a) Baires, S. V.; Ivanov, V. B.; Ivanov, B. E.; Krokhina, S. S.; Efremov, Y. Y.; Korshunov, R. L. Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya. 1984, 1, 220-223. b) Nabiev, O. G.; Nabizade, Z. O.; Kostyanovsky, R. G. Mendeleev Commun. 2009, 19, 281-283. 18. a) Pochini, A.; Puglia, G.; Ungaro, R. Synthesis. 1983, 11, 906-907. b) Fairhurst, R. A.; Heaney, H.; Papageorgiou, G.; Wilkins, R. F. Tetrahedron Lett. 1988, 29, 5801-5804. c) Sun,
W.; Lin, H.; Zhou, W.; Li, Z. RSC Advances. 2014, 4, 7491. d) Heaney, H.; Papageorgiou, G.; Wilkins, R. F. Tetrahedron. 1997, 53, 13361-13372.
59 19. a) Roper, J. M.; Everly, C. R. The Journal of Organic Chemistry. 1988, 53, 2639-2642. b) Gutsche, C. D.; Nam, K. C. J. Am. Chem. Soc. 1988, 110, 6153-6162. 20. Moehrle, H.; Troester, K. Arch. Pharm. 1982, 315, 397-405. 21. a) Spencer, T. A.; Li, D.; Russel, J. S. J. Org. Chem. 2000, 65, 1919-1923. b) Tomkinson, N. C. O.; Willson, T. M. J. Org. Chem. 1998, 63, 9919-9923. c) Polishchuk, A. P.; Timofeeva, T. V.; Antipin, M. Y.; Gerr, R. G.; Kuloshov, V. I.; Struchkov, Y. T.; Payusova, I. K.; Tolmachev,
A. V. Zhurnal Strukturnoi Khimii. 1990, 31, 67-74. 22. Webb, W. P. Auto-ignition method. 2,826,515, United States, 1958.
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60 CHAPTER 3. ARENECHROMIUMTRICARBONYL COMPLEXES OF THE MIXED GROUP 14 METHANES
3.1 Abstract
The elements of Group 14 exhibit a great diversity in their properties, oscillating from the nonmetallic carbon to the well-known metals tin and lead. We have previously reported the formation of a series of group 14 substituted methanes, (R3E)nCH4-n (E = Si, Ge, Sn, Pb; R = combinations of methyl and aryl groups; n = 2,3,4) and also used these materials where an R group
= C6H5 to form Cr(CO)3 derivatives. During such studies we observed significant C-E bond cleavage products to form (R3E)n-1CH4-n derivatives and proposed that the Cr(CO)3 substituent was responsible for this E-C bond activation.1 The research in this chapter involves studies aimed at elucidating some of the parameters associated with group 14-C bond activation by the Cr(CO)3 substituents.
3.2 Research Objectives
Synthesize the compounds (PhMe2Si)(Me3Ge)CH2 and (PhMe2Ge)(Me3Si)CH2.
Treatment of the latter compounds with Cr(CO)6 to form the corresponding Cr(CO)3 derivatives.
Study the hydrolytic stability of the Cr(CO)3 complexes and illustrate the potential activation of E-C bonds by the transition metal substituent.
61 3.3 Introduction
3.3.1 The Carbon Family
The elements of Group 14, carbon, silicon, germanium, tin and lead, represent an entertaining area for study since their properties are distinctive, yet are also capable of having many similarities, of which catenation is a prime example. Group 14 is also called the carbon family. The elements of this group show considerable diversity in their physical and chemical properties, where C is nonmetal, Si and Ge are metalloids, and Sn and Pb are metals. Except for germanium, all these elements are familiar in daily life either in the form of compounds or as the pure element. Carbon, the first and the lightest element of this group 14 is the so-called building block of life. It forms an almost infinitive miscellany of compounds, is the central element of organic chemistry and one of the most common elements on Earth. Silicon is a fundamental component of the Earth’s crust, the second most abundant element. Tin and lead are found in mineral deposits, and are useful as metals and alloys in many applications. Their abundances in the crust are lower than those of some so-called rare elements. Germanium, on the other hand, is mostly found in small concentrations in coals and is one of the rarer elements.2
3.3.2 Catorcanes
Several years ago, our group reported the formation of a group 14-substituted methane, named catorcane, in which all the group 14 elements were present, (silyl)(germyl)(stannyl)(plumbyl)methanes (Fig. 3.1).3
Figure 3.1 Structure of a catorcane.
62 Di-, tri-, and tetrasubstituted methanes are versatile and valuable C reagents in organic and organometallic synthesis. Homoleptic methyl groups are used as stabilizing derivatives to isolate kinetically labile methylenes and dimetallenes of group 14.4 Nonetheless, heteroleptic methyl systems have received only scant attention.3,5
3.3.3 Metallocenes
In the early 1950s, organometallic chemistry had an incredible breakthrough thanks to the
5 unintentionally synthesis of ferrocene and the elucidation of its structure, Fe(η -C5H5)2. Before this discovery, the covalent bond (e.g., M-CH3) and the coordinate covalent bond (e.g., M-CO) were the only concepts regarding metal-carbon bonding. Therefore, the proposed theory of a metal- ligand bond between a metal and the π orbitals of C5H5 had a truly revolutionary impact. Ferrocene was the first molecule known as metallocene, consisting of an iron (II) ion between two parallel cyclopentadienyl (Cp) rings, also named as sandwich compound. The Cp ligand is a typical example of many where the π-system of an organic molecule binds directly to a metal bond via a M d(π)-p(π) interaction. This discovery spawned the beginning of a new field within organometallic chemistry and was worthy of recognition and led to the award of the Nobel Prize to Wilkinson and Fischer.2c,6
3.3.4 Arene-Chromium Tricarbonyl complexes
Arenes are aromatic hydrocarbons and many of them are considered as ligands due to the availability of the 6 π-electrons. η6-Arenes are considered to be neutral ligands occupying three coordination sites at a metal. Derivatives of benzene, containing six pπ orbitals, can contribute with 6e to the metal. Large numbers of ligands are known to bond to a metal atom through carbon as well as hundreds of organic molecules containing linear or cyclic π systems. Nonetheless the cyclopentadienyl is the aromatic ligand best known, sandwich compounds of the general formula
63 M(arene)2 which possess structures analogous to metallocenes and monoarenes derivatives
2b,6 [M(arene)Ln] are also recognized. Despite the vast amount of metals that can be used to complex aromatic rings, the chromium tricarbonyl compounds has being the most recognized as synthetic intermediates owing to their stability on air, often crystalline, moderately air sensitive in solution, sensitive to oxidizing agents and to light. (η6-Arene)chromium tricarbonyl is a yellow crystalline material, and adopts a
“piano stool” geometry as a result of the planar arrangement of the aryl group and the 3CO ligands as the “legs” of the stool on the Cr-bond axis (Fig. 3.2).7
Figure 3.2 (η6-arene)chromium tricarbonyl, “piano stool” geometry.
The substitution of ligands is most commonly used for the preparation of compounds of group 6 metals, in other words, the substitution of CO groups in metal carbonyl complexes is a most general method for the preparation of carbonyl arene compounds (eq. 3.1):
(3.1)
The [Cr(arene)(CO)3] complexes, specifically, are synthesized mostly by thermolysis of
Cr(CO)6 in a high boiling point solvent under an inert atmosphere. The sublimation of Cr(CO)6 is reduced using a mixture of the arene, dibutyl ether and THF as a solvent under reflux for a few days.7 The literature on carbonyl arene complexes is abundant for chromium, but decreases
64 abruptly for molybdenum and particularly tungsten. The synthesis of [M(arene)(CO)3] derivatives from [M(CO)6] complexes is much more limited for Mo and W than from Cr. The high sensitivity to oxygen and the long reaction times at high temperature often results in low yields for arenes. The yields in the synthesis of these complexes decrease according to the sequence Cr > W > Mo.2c,8 The CO ligand is a π acceptor and weak π donor that can interact with the metal atom with 2 electrons based on σ donor ability alone. The Cr atom has 6 electrons beyond its noble gas core and each CO is considered as 2 electron donor. Therefore, Cr(CO)6 is considered an 18-electron complex, which is thermally stable and can be sublimed without decomposition. Having in mind this, the [Cr(arene)(CO)3] is also an 18-electron molecule, 6 electrons for Cr, 6 electrons for the benzene ring, and 6 for the 3CO ligands.2b,2d The first (η6-arene)tricarbonylchromium complex were reported in 1958, independently by three groups, by the reaction of benzene with chromium hexacarbonyl. Because of its simplicity, many such compounds have been synthetized since that discovery.9
The benzene fragment, in the (benzene)Cr(CO)3 compound, undergoes significant upfield chemical shifts relative to free benzene due to geometry and electronic changes, involving the electron withdrawing ability of the Cr(CO)3, that makes the arene prone to nucleophilic attack and the aryl and benzylic hydrogens becomes more acidic. The C-C bonds distances in arene rings which are coordinated to the metal atom are longer than those in free molecules. Moreover, the steric bulk of the Cr-carbonyl moiety effectively shields one face of the arene, and has found use as a ‘stereodirecting’ group. On the other hand, the IR bands of the benzene spectrum become shifted to lower frequencies after the benzene moiety is coordinated to the metal. In fact, the 13C
NMR of [Cr(arene)(CO)3] exhibit a pattern of the arene resonances analogous to those to the free/non-coordinated benzene but displaced upfield. The δ 1H chemical shift of the free benzene moiety becomes shifted toward upfield after coordination to the metal.2b,10
The explanation of the upfield shifts is more controversial. One of the causes of this upfield shifts is, the decrease in the ring current after complexation of the arene ring with the metal/ and an overall withdrawal of π electrons from the arene ring by the Cr(CO)3 unit, the general effect 65 being a reduction in the deshielding of the aromatic protons. Thus, in an external magnetic field
(Bo) as would be encountered in an NMR experiment, the π-electrons of the aromatic compound will circulate in such a manner as to set up a field in opposition to the applied field. As a result,
11 the HA is deshielded, moving its resonance to very low field, Fig. 3.3.
Figure 3.3 Aromatic Ring Current.
The Cr(CO)3 fragment can hereby be described as an “electron sink” disrupting the prevalent aromaticity of the benzene ring.12
After being transformed, the Cr(CO)3 moiety can be easily removed to liberate the
7 modified arene by exposure to light or treatment with I2, CO, or other reagents. The Cr(CO)3 unit has the capacity to stabilize benzylic cations and anions, for that reason it has been labeled as “hermaphroditic.”13 Transition metal complexation is attractive because of the rich structural, stereochemical, and electronic features of metal-arene interactions and their utility in organic synthesis, and many such systems have been reported.14
6 The (η -arene)Cr(CO)3 compounds have several applications: they have properties of Lewis acids, and are utilized in many organic reactions, in the design of new molecules incorporating Cr(CO)3 moiety holding specific stereochemical properties. Tricarbonyl arene complexes of group 6 are used as effective catalysts for hydrogenation of dienes and polyenes to alkenes, for polymerization of olefins and dienes, and for alkylation, acylation, dehydrohalogenation and sulfonylation reactions, as well as in the asymmetric synthesis of natural
66 products.14-15 The selectivity decreases in the series Cr>Mo>W, while the catalytic activity increases as follows: Cr (3.2) Surprisingly, the thermal treatment of 1b and Cr(CO)6 with ‘wet’ n-butyl ether/THF solvent mixture led to the unexpected formation of arenechromiumtricarbonyl silanol, 3, derivative and the cleavage of the C-Sn bond (eq. 3.3).1 (3.3) Transition metal complexation is attractive because of the rich structural, stereochemical, and electronic features of metal-arene interactions, and their utility in organic synthesis, therefore transition-metal complexes containing π-bound arene ring have been widely investigated.14 The chosen synthesis of such starting materials involves sequential preparation of halomethylsilanes and substitution of the halogen atom via Grignard or organolithim reagents, as outlined in Scheme 3.1. 67 Scheme 3.1 Synthetic route to prepare the (arene)tricarbonyl chromium derivatives. A brief background to these synthetic pathways in presented below. 3.3.5 Synthesis of (Halomethyl)silanes As reported by Kobayashi and Pannell in 1991,16 the alkylation of chlorosilanes by in situ generated (chloromethyl)lithium is an excellent route to create (halomethyl)silanes in good yields They are excellent starting materials for the synthesis of a range of organosilicon derivatives. The synthetic procedure for the formation of (halomethyl)silanes involves the use of n-BuLi in THF at low temperatures (-70 °C) to produce in situ ClCH2Li as a suitable vehicle for introduction of the CH2Cl functionality onto silicon substrate (eq. 3.4). (3.4) 3.3.6 Organomagnesium Reagents In organometallic chemistry, the Grignard reaction is one of the most important reactions, which come along with a famous quotation: “…every chemist has carried out the Grignard 68 reactions at least once in his lifetime…” (eq. 3.5).17 Usually a polar solvent is needed for such chemistry to stabilize the positively charge Mg atom or ion.17-18 (3.5) Halogen/magnesium exchange reaction is another common method to prepare a wide range of functionalized aryl, alkenyl and heteroaryl Grignard reagents, Scheme 3.2.19 Scheme 3.2 Halogen/Magnesium exchange reactions. 3.4 Results and Discussion In order to obtain the (arene)tricarbonylchromium silanes (2a, 6a) and germane derivatives (2d, 6b), Fig. 3.4, we had to start from the beginning. Figure 3.4 (arene)tricarbonylchromium-silane and -germane derivatives. 69 Based on the previous literature, the following synthetic route described in Scheme 3.1 was used to prepare the aimed derivatives. 3.4.1 Synthesis of (halomethyl)-silane and -germane Step I, Scheme 3.1: The synthetic procedure to form (halomethyl)-silanes (5a) and - germanes (5b) involves the alkylation of chlorosilanes (4a) and chlorogermanes (4b), respectively, with (chloromethyl)lithium, generated in situ from the reaction of n-butyllithium and bromochloromethane, in THF at -70 °C (eq. 3.6). (3.6) The ClCH2Li is very unstable even at low temperatures, therefore, once it has been - - generated, it has to be used in situ to have this direct replacement of [Cl] by [CH2Cl] . The products formed are distillable liquids and were characterized by NMR spectroscopy shown in Fig. 3.5 (A 3.1) for the complex 5a and in the appendix section (A 3.2) for derivative 5b. 70 29 13 Figure 3.5 Si NMR (left) and C NMR (right) spectra of 5a in CDCl3. The silicon derivative 5a20 was obtained with 83% yield, while 5b,21 the Ge analog was obtained in 75% yield. 3.4.2 Synthesis of Di-substituted Methanes Step III, Sheme 3.1: The next step involves the reaction of Mg0 with the (halomethyl)silane (5a) or -germane (5b) in diethyl ether (Et2O) to led the formation of the Grignard derivatives 1a and 1d, respectively (eq. 3.7). (3.7) Both products are known colorless liquids, 1a22 was obtained in very good yield (86%), however, only a 30% yield was obtained for the germanium derivative 1d23. The products were 71 characterized by NMR spectroscopy, and the NMR spectrum of derivative 1a is shown in Fig. 3.6 (A 3.3). 29 13 Figure 3.6 Si NMR (left) and C NMR (right) spectra of 1a in CDCl3. 3.4.3 Formation of the Arene-Chromium Tricarbonyl Derivatives Step II, Scheme 3.1: The thermal reaction of 5a-b with Cr(CO)6 under reflux with (7:1) n- Bu2O/THF solvent mixture during 3 days at 90-140 °C, resulting in the formation of yellow-green crystalline chromium tricarbonyl complexes, 6a with 64% yield and 6b with 60% yield (eq. 3.8). (3.8) We were able to obtain the single X-Ray crystal structure of (η6- C6H5)Cr(CO)3Me2SiCH2Cl, 6a, illustrated on the Fig. 3.7. The peculiar stereochemical control 72 6 effected by the Cr(CO)3 moiety gives it the classical η -arene-ML3 form of a three-legged piano stool with a planar benzene ring seat lying symmetrically above the π-bonded chromium atom with the three carbonyl groups oriented in a tripod fashion in opposite direction to the ring, in which the chloromethylene group is anti-fashion with respect to the chromium-arene moiety.7,24 Figure 3.7 Single X-Ray structure of 6a. To our surprise, the chlorine atom is not participating with any interaction to generate the HB network, only the interaction between the carbonyl groups and the hydrogens on the methylene moiety are the responsible of that arrangement. The HB’s network CO···H of 2.65 and 2.69 Å, Fig. 3.8. 73 Figure 3.8 Section of the crystal packing of 6a, showing the HB network. The structural parameters and selected bond angles and distances are provided in the Appendix section (A 3.4). The Cr-C(ring) bond distances, approximately 2.230 Å and the Cr-C(CO groups) bond distance of 1.842 Å are typical of arene chromium tricarbonyl complexes.8,25 The 29Si NMR and 13C NMR spectra of compound 6a is shown in Fig. 3.9. The reactivity of the coordinated ring changes dramatically due to complexation with Cr atom causing a strong electron withdrawing character. This reactivity is reflected by the differences of the NMR spectra bellow and those illustrated in Fig. 3.4 from compounds 5a and 6a respectively. The 13C NMR resonances of the arene unit, 6a, became shifted toward upfield (in the range of 90.0-99.3 ppm) than the 5a ones (127.9-135.9 ppm), as a consequence to the decrease in the ring current of the benzene. This coordination also provokes changes on the 29Si NMR spectra, the chemical shift of the silicon atom on 6a is deshielded (0.98 ppm) upon coordination due electron withdrawing effect of the chromium moiety, compared to 5a molecule (-2.67 ppm). 74 29 13 Figure 3.9 Si NMR (left) and C NMR (right) spectra of 6a in CDCl3. Those are clear examples of the typical NMR spectroscopic properties of compounds ‘before and after’ coordination to the Cr(CO)3 unit (A 3.4-3.5). Step IV, Scheme 3.1: The derivative 2a, a yellow-green crystalline complex with 80% yield, was obtained using the previous procedure by the thermal reaction of 1a with Cr(CO)6 under reflux with (7:1) n-Bu2O/THF solvent mixture during 3 days at 90-140 °C (eq. 3.9). (3.9) 6 The single X-ray crystal structure of [(η -C6H5)Cr(CO)3Me2Si](Me3Ge)CH2 (2a) was obtained, displaying also a three-legged piano stool. It crystallizes in P-1 space group (Triclinic crystal system), Fig. 3.10. 75 Figure 3.10 Single X-Ray crystal structure of 2a complex. The 29Si NMR and 13C NMR spectra of compound 2a are illustrated in Fig. 3.11. As expected, the NMR spectra of 2a derivative exhibited an upfield displacement of chemical shifts, on 13C NMR, of the aromatic carbons of ~30-40 ppm compared to the NMR spectra of 1a. Where the 29Si NMR spectra suffered a downfield change from -2.57 ppm (1a) to 0.91 ppm (2a). 29 13 Figure 3.11 Si NMR (left) and C NMR (right) spectra of 2a in C6D6. 76 The structural parameters and selected bond angles and distances are provided in the Appendix section (A 3.6). The compound 2d has not been synthesized as yet due to the really low yield obtained of its starting material 1d. 3.4.4 Hydrolysis Reaction We attempted the hydrolysis of compound 1a, expecting having similar behavior as previously conjectured for the Si(Ge)(Sn)-methane,1 i.e. cleavage of a C-Group 14 bond to form 6 (η -(CO)3CrC6H6)SiMe2OH. The obtained results using 1a complex shown neither significant activation of the molecule nor formation of silanol derivative, not even adding a drop of water, either acidic or basic, or using a ‘wet’ solvent mixture in the thermal reaction, only the predicted compound 2a and starting material was detected (Scheme 3.3, i). Scheme 3.3 Hydrolysis reactions using wet solvents (i, ii) or different acids and bases (iii). 77 No reaction was noted from the treatment of 2a with ‘wet’ THF (ii). We also tried the reactions of 2a with different acids and bases in order to observe some cleavage in the molecule but no change was distinguished (iii). 3.5 Conclusions In general, the synthesis of the silicon and germanium derivatives were obtained in good yields. Single X-Ray crystal structures were obtained for two derivatives (1a, 2a) showing the classical piano stool conformation of the arene chromium tricarbonyl complexes. The NMR spectra help us to illustrate the effect of the Cr(CO)3 in the molecule, causing an upfield shifts. In the hydrolytic study, to date no cleavage has been noted, thus we are still in doubt the factors 1 responsible for the reported cleavage. It has been proposed that the Cr(CO)3 moiety was responsible for the Sn-C bond activation. At present, it seems like the Sn in derivative 2b is the responsible for the molecule activation and the cleavage of both the Si-C and Sn-C bonds. Thus, the synthesis of homologous derivatives with Si, Sn and Ge, may help to solve the mystery of this bond cleavage/activation (Fig. 3.12). Figure 3.12 Homologous derivatives with Si, Sn and Ge. 78 3.6 Experimental All manipulations were performed using standard Schlenk techniques under argon atmosphere. Tetrahydrofuran (THF) was dried and distilled over sodium and benzophenone ketal. Diethyl ether, benzene, toluene and hexanes were dried and distilled over sodium wire. The following reagents were purchased from Aldrich and used as received: n-butyllithium solution (1.6M in hexanes), Cr(CO)6, Me3SiCl, BrCH2Cl and magnesium metallic. PhMe2SiCl, PhMe2GeCl and Me3GeCl were purchased from Gelest. NMR spectra were recorded on Bruker 300 MHz or JEOL 600 MHz spectrometer using 1 13 1 13 CDCl3 (7.26 ppm H, 77.3 C) or C6D6 (7.15 ppm H, 128.0 C) as solvent. The crystal structures were determined using a Bruker APEX CCD diffractometer with monochromatized MoKα radiation (λ = 0.71073 Å). Elemental analyses were performed by Galbraith Laboratories. 3.6.1 Synthesis of (halomethyl)-silane and -germane derivatives Into a 500 mL three-necked flask equipped with a magnetic stirring bar, rubber septum, nitrogen inlet tube, and low-temperature thermometer were added 1.0 mol of PhMe2ECl (E = Si (4a), Ge (4b)) and 1.1 mol of BrCH2Cl in 100 mL of dry THF. To this mixture, maintained between -70 and -60 °C, was added on the cold wall of the flask, via syringe over 1 hour, 40.0 mL (0.064 mol) of a 1.6 M solution of n-butyllithium in hexane. The solution was warmed to room temperature during 80 minutes. The solvent was evaporated in vacuo overnight. The residue was extracted into hexane, and the rest of the solution was filtered over celite. The solvent was removed, and the residue was distilled on a 20-cm Vigreux column under vacuum. 1 PhMe2SiCH2Cl (5a): Yield: 83%, b.p.100-102 °C/15 mmHg, colorless liquid. H NMR (CDCl3, 300 MHz): δ 0.64 (s, 6 H, (CH3)2Si), 3.14 (s, 2 H, CH2), 7.59 (t, 3H, Ph), 7.83 ppm (d, 2H, Ph). 13 C NMR (CDCl3, 300 MHz): δ -4.62 ((CH3)2Si), 30.2 (CH2), 127.9, 129.6, 133.6, 135.9 (Ph) ppm. 29 Si NMR (CDCl3, 300 MHz): δ -2.67 ppm. Reported: Yield: 80-81%, b.p. 115 °C/23 mmHg, 79 1 colorless liquid. H NMR (CDCl3, 400 MHz): δ 0.42 (s, 6 H), 2.96 (s, 2 H), 7.35-7.44 (m, 3H), 13 7.52-7.57 ppm (m, 2H). C NMR (CDCl3, 101 MHz): δ -4.5, 30.4, 128.0, 129.7, 133.7, 136.1 ppm.20 1 PhMe2GeCH2Cl (5b): Yield 75%, b.p. 114-115 °C/15 mmHg. H NMR (CDCl3, 300 MHz): δ 13 0.80 (s, 6 H, (CH3)2Ge), 3.34 (s, 2 H, CH2), 7.61 (t, 3 H, Ph), 7.82 ppm (d, 2H, Ph). C NMR (CDCl3, 300 MHz): δ -4.55 ((CH3)2Ge), 30.85 (CH2), 128.5, 129.0, 133.5, 138.8 ppm (Ph). Reported: b.p. 112.5 °C/14 mmHg.21 3.6.2 Synthesis of Arene-Chromium Tricarbonyl Derivatives A 250 mL three-necked round-bottom flask with rubber septum, a magnetic stirring bar, nitrogen inlet on the condenser, was charged with 1.0 mol of PhMe2ECH2Cl (E = Si (5a), Ge (5b)), 1.2 mol of Cr(CO)6 in 7:1 solvent mixture ratio of n-butyl ether and dry THF. The mixture was heated in oil bath under nitrogen atmosphere at 90 °C for 24 hours. After this reaction time, the temperature of the oil was raised to 140 °C and the reaction mixture was heated at this temperature for 2 days. The reaction mixture was cooled to room temperature and filtered over Celite. n-Butyl ether was removed by flash distillation under vacuum and the yellow residue was extracted with 20 mL of a 2:1 mixture of hexane and toluene, filtered and left in the refrigerator. The compound was recrystallized from a mixture of hexane and toluene to yield the formation of the product. 6 1 [(η -C6H5)Cr(CO)3Me2Si]CH2Cl (6a): Yield: 64%, yellow crystals. H NMR (CDCl3, 300 MHz): 13 δ 0.44 (s, 6 H, (CH3)2Si), 2.94 (s, 2 H, CH2), 5.18 (t, 3H, Ph), 5.47 ppm (d, 2H, Ph). C NMR (CDCl3, 300 MHz): δ -5.06 ((CH3)2Si), 29.6 (CH2), 90.0, 93.9, 95.4, 99.3 (Ph), 232.4 ppm (CO). 29 Si NMR (CDCl3, 300 MHz): δ 0.98 ppm. 80 6 1 [(η -C6H5)Cr(CO)3Me2Ge]CH2Cl (6b): Yield: 60%, yellow crystals. H NMR (C6D6, 300 MHz): 13 δ 0.28 (s, 6 H, (CH3)2Ge), 2.65 (s, 2 H, CH2), 4.29 (t, 3 H, Ph), 4.67 ppm (d, 2H, Ph). C NMR (C6D6, 300 MHz): δ -4.25 ((CH3)2Ge), 30.6 (CH2), 91.9, 95.4, 98.6, 99.5 (Ph), 233.9 ppm (CO). A 250 mL three-necked round-bottom flask with rubber septum, a magnetic stirring bar, nitrogen inlet on the condenser, was charged with 1.0 mol of PhMe2Si(Me3Ge)CH2 (1a), 1.2 mol of Cr(CO)6 in 7:1 solvent mixture ratio of n-butyl ether and dry THF. The mixture was heated in oil bath under nitrogen atmosphere at 90 °C for 24 hours. After this reaction time, the temperature of the oil was raised to 140 °C and the reaction mixture was heated at this temperature for 2 days. The reaction mixture was cooled to room temperature and filtered over Celite. n-Butyl ether was removed by flash distillation under vacuum and the yellow residue was extracted with 20 mL of a 2:1 mixture of hexane and toluene, filtered and left in the refrigerator. The compound was recrystallized from a mixture of hexane and toluene to yield the formation of the product. 6 1 [(η -C6H5)Cr(CO)3Me2Si](Me3Ge)CH2 (2a): Yield: 80%, m.p. 78-78.5 °C, yellow crystals. H NMR (C6D6, 300 MHz): δ -0.12 (s, 2 H, CH2), 0.16 (s, 9 H, (CH3)3Ge), 0.23 (s, 6 H, (CH3)2Si), 13 4.41 (t, 2H, Ph), 4.73 (t, 1 H, Ph) 4.87 ppm (d, 2 H, Ph). C NMR (C6D6, 300 MHz): δ -1.05 29 ((CH3)2Si), 0.69 ((CH3)3Ge), 2.05 (CH2), 90.5, 95.0, 99.1, 100.9 (Ph), 233.7 ppm (CO). Si NMR 1 (C6D6, 300 MHz): δ -0.91 ppm. Reported: Yield: 49%, m.p. 79 °C. H NMR (C6D6, 300 MHz): δ -0.18 (s, 2 H, CH2), 0.09 (s, 9 H, GeMe3), 0.16 (s, 6 H, SiMe2), 4.35 (t, J = 6 Hz, 2 H, Ph), 4.80 (t, 13 J = 6 Hz, 1 H, Ph) 4.82 ppm (d, J = 6 Hz, 2H, Ph). C NMR (C6D6, 300 MHz): δ -0.63 (SiMe2), 29 0.72 (GeMe3), 2.09 (CH2), 90.6, 95.0, 99.1 (Ph), 100.9 (ipso), 233.7 ppm (CO). Si NMR (C6D6, 300 MHz): δ 1.13 ppm.1 81 3.6.3 Synthesis and Reaction of Grignard Reagents The Grignard reagent PhEMe2CH2MgCl was synthesized from 1.0 mol of PhEMe2CH2Cl (E = Si (5a), Ge (5b)) and 1.2 mol of Mg0 in 30 mL of dry diethyl ether. The Grignard reagent was added dropwise to 1.0 mol Me3E’Cl (E = Si (5a), E’ = Ge; E = Ge (5b), E’ = Si) in 30 mL of diethyl ether at 0 °C, to subsequently, yield the formation of products 1a and 1d respectively. The reaction mixture was stirred at this temperature for about 3-4 hours and then brought to room temperature slowly and stirred for 12 hours. Diethyl ether was removed under vacuum, and salts were precipitated with 50 mL of hexane. After filtration and removal of solvents, followed by distillation, the colorless liquid product was collected. 1 PhMe2Si(Me3Ge)CH2 (1a): Yield: 86%, b.p. 123-125 °C/5 mmHg. H NMR (CDCl3, 300 MHz): δ 0.14 (s, 2 H, CH2), 0.31 (s, 9 H, (CH3)3Ge), 0.49 (s, 6 H, (CH3)2Si), 7.51 (t, 3H, Ph), 7.71 ppm 13 (d, 2H, Ph). C NMR (CDCl3, 300 MHz): δ -0.12 ((CH3)2Si), 0.80 ((CH3)3Ge), 2.61 (CH2), 127.6, 29 128.9, 133.1, 141.1 ppm (Ph). Si NMR (CDCl3, 300 MHz): δ -2.57 ppm. Reported: Yield: 92%, 1 b.p. 150 °C/13 mmHg. H NMR (CDCl3): δ 0.08 (s, 2 H, CH2), 0.10 (s, 9 H, Me3Ge), 0.28 (s, 6 H, 22 Me2Si), 7.30-7.36 (m, 3H, Ph), 7.49-7.54 ppm (m, 2H, Ph). 29 PhMe2Ge(Me3Si)CH2 (1b): Yield 30%, b.p. 90-92 °C/13 mmHg. Si NMR (CDCl3, 300 MHz): 1 δ 1.25 ppm. Reported: Yield: 35%, b.p. 95-98 °C/20 mmHg. H NMR (300 MHz): δ -0.004 (CH2), 13 0.02 (SiMe3), 0.40 (GeMe2), 7.44, 7.47 ppm (Ph). C NMR (300 MHz): δ -0.67 (GeMe2), 1.24 29 23 (SiMe3), 2.32 (CH2), 128.9, 133.2, 134.0, 143.2 ppm (Ph). Si NMR (300 MHz): δ 1.62 ppm. 3.6.4 Hydrolytic Study Attempt 1. A 250 mL three-necked round-bottom flask with rubber septum, a magnetic stirring bar, nitrogen inlet on the condenser, was charged with 1.0 mol of PhMe2Si(Me3Ge)CH2 (1a), 1.2 mol of Cr(CO)6 in 7:1 solvent mixture ratio of n-butyl ether and ‘wet’ (regular) THF, and an extra 82 drop of water. The mixture was heated in oil bath under nitrogen atmosphere at 90 °C for 24 hours. After this reaction time, the temperature of the oil was raised to 140 °C and the reaction mixture was heated at this temperature for 2 days. The reaction mixture was cooled to room temperature and filtered over Celite. The NMR spectra showed presence of starting material (1a) and formation of the chromium derivative 2a. Attempt 2. In a typical experiment, a Pyrex NMR tube was charged with 0.248 mmol (100 mg) of 2a in 0.17 mL of wet THF, 1.18 mL of n-Bu2O, 0.3 mL of C6D6, and sealed under vacuum. The tube was leave it at room temperature (25 °C) and monitored by 13C and 29Si NMR spectroscopy. After a couple of days, no reaction was observed, only the presence of the starting material, 2a. Attempt 3. In a typical experiment, a Pyrex NMR tube was charged with 0.248 mmol (100 mg) of 2a in 0.17 mL of wet THF, 1.18 mL of n-Bu2O, 0.3 mL of C6D6, and sealed under vacuum. The tube was heated to 120 °C in an oil bath, and monitored by 13C and 29Si NMR spectroscopy. Any change was observed after a couple of days of reaction, only the presence of the starting material, 2a. Attempt 4. In a typical experiment, a Pyrex NMR tube was charged with 0.050 mmol (20 mg) of 2a, 20 drops of acetic acid, 0.1 mL of dry THF, 0.3 mL of C6D6, and sealed under vacuum. The tube was heated from 25-90 °C in an oil bath, and monitored by 13C and 29Si NMR spectroscopy. Any change was observed after a couple of days of reaction, only the presence of the starting material, 2a. Attempt 5. In a typical experiment, a Pyrex NMR tube was charged with 0.050 mmol (20 mg) of 2a, 20 drops of pyridine, 0.1 mL of dry THF, 0.3 mL of C6D6, and sealed under vacuum. The tube was heated from 25-90 °C in an oil bath, and monitored by 13C and 29Si NMR spectroscopy. Any 83 change was observed after a couple of days of reaction, only the presence of the starting material, 2a. Attempt 6. In a typical experiment, a Pyrex NMR tube was charged with 0.050 mmol (20 mg) of -4 2a, 20 drops of HCl (1x10 M), 0.1 mL of dry THF, 0.3 mL of C6D6, and sealed under vacuum. The tube was heated from 25-90 °C in an oil bath, and monitored by 13C and 29Si NMR spectroscopy. Any change was observed after a couple of days of reaction, only the presence of the starting material, 2a. Attempt 7. In a typical experiment, a Pyrex NMR tube was charged with 0.050 mmol (20 mg) of -4 2a, 20 drops of NaOH (1x10 M), 0.1 mL of dry THF, 0.3 mL of C6D6, and sealed under vacuum. The tube was heated from 25-90 °C in an oil bath, and monitored by 13C and 29Si NMR spectroscopy. Any change was observed after a couple of days of reaction, only the presence of the starting material, 2a. 3.7 References 1. Sharma, H. K.; Cervantes-Lee, F.; Pannell, K. H. J. Organomet. Chem. 2010, 695, 1168-1174. 2. a) Colvin, E. Silicon in Organic Synthesis; Butterworth and Co., 1981. b) Miessler, G. L.; Fischer, P. J.; Tarr, D. A. Inorganic Chemistry; Fifth edition ed.; Pearson, 2014. c) Pruchnik, F. P. Organometallic Chemistry of the Transition Elements; Plenum Press, 1990. d) Atkins, P.; Overton, T.; Rourke, J.; Weller, M.; Armstrong, F.; Hagerman, M. Shiver and Atkins' Inorganic Chemistry; Fifth ed.; Oxford University Press: Great Britain, 2010. 3. Cervantes-Lee, F.; Sharma, H. K.; Haiduc, A. M.; Pannell, K. 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Chem. 2007, 81, 783- 797. ****BREAK 86 APPENDIX Chapter 1 A 1.1 1 Figure A.1 H NMR spectrum of the above reaction at room temperature in C6D6 (Table 1.1). Table A.1 Calculation of the relative yields of the disiloxanes formed at room temperature from the above reaction 1 and H NMR spectrum in C6D6 (Table 1.1). Compound #H Integration, ʃ ʃ / #H % Me 3SiOSiMe3 18 1.02 0.06 85% Me3SiOSiEt3 24 0.21 0.01 15% Et3SiOSiEt3 30 0 0 0 Ʃ 0.07 87 A 1.2 1 Figure A.2 H NMR spectrum of the above reaction at 50 °C in C6D6 (Table 1.1). 88 A 1.3 29 13 Figure A.3 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature (Table 1.1). 1 Figure A.4 H NMR spectrum of the above reaction at room temperature in C6D6 (Table 1.1). 89 A 1.4 29 13 Figure A.5 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 50 °C (Table 1.1). 1 Figure A.6 H NMR spectrum of the above reaction at 50 °C in C6D6 (Table 1.1). 90 A 1.5 29 13 Figure A.7 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature (Table 1.1). 1 Figure A.8 H NMR spectrum of the above reaction at room temperature in C6D6 (Table 1.1). 91 A 1.6 29 13 Figure A.9 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 50 °C (Table 1.1). 1 Figure A.10 H NMR spectrum of the above reaction at 50 °C in C6D6 (Table 1.1). Table A.2 Calculation of the relative yields of the disiloxanes formed at room temperature from the above reaction 1 and H NMR spectrum in C6D6 (Table 1.1) Compound #H Integration, ʃ ʃ / #H % Me 3SiOSiMe3 18 2.17 0.02 48% Me3SiOSiPh2Me 12 1.35 0.11 42% Ph2MeSiOSiPh2Me 6 0.13 0.12 10% Ʃ 0.26 92 A 1.7 29 13 Figure A.11 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 50 °C (Table 1.1). 1 Figure A.12 H NMR spectrum of the above reaction at 50 °C in C6D6 (Table 1.1). 93 A 1.8 29 13 Figure A.13 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 21 hours plus 3 hours at 50 °C, denoted in red color (Table 1.2). 1 Figure A.14 H NMR spectrum of the above reaction in C6D6 (Table 1.2). 94 A 1.9 29 13 Figure A.15 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 3 hours plus 1 hour at 50 °C, denoted in red color (Table 1.2). 1 Figure A.16 H NMR spectrum of the above reaction in C6D6 (Table 1.2). 95 A 1.10 29 13 Figure A.17 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 15 minutes plus 17 hours at 50 °C, denoted in red color (Table 1.2). 1 Figure A.18 H NMR spectrum of the above reaction in C6D6 (Table 1.2). 96 A 1.11 29 13 Figure A.19 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 19 hours plus 102 hours at 50 °C, denoted in red color (Table 1.2). 1 Figure A.20 H NMR spectrum of the above reaction in C6D6 (Table 1.2). 97 A 1.12 Siloxane formation of one-pot reactions using different hydrosilanes and chlorosilanes with DMF and Mo-catalyst (1:1:5:5%). Table A.3 Siloxane formation of one-pot reaction, described above, using different hydrosilanes and chlorosilanes with DMF and Mo-catalyst (1:1:5:5%). R3SiCl Me3SiCl Et3SiCl PhMe2SiCl Ph2MeSiCl Ph3SiCl Products RT 50 °C RT - 50 °C RT - 50 °C RT - 50 °C RT - 50 °C R3SiH 0% 19% - 0% 16% 9% Et3SiH 85% 60% - 76% 61% 70% 15% 21% 100% 24% 23% 26% 15% 15% 45% - 32% PhMe2SiH 50% 41% 22% - 42% 35% 44% 33% 100% 26% 6% 10% 39% 44% - Ph2MeSiH 60% 48% 25% 47% - 34% 42% 36% 9% 100% 65% 52% Ph3SiH 21% 12% 14% 36% 98 A 1.13 29 13 Figure A.21 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 3 hours plus 6 hours at 50 °C, denoted in red color (Table 1.2). 1 Figure A.22 H NMR spectrum of the above reaction in C6D6 (Table 1.2). 99 A 1.14 29 13 Figure A.23 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 15 hours plus 4 hours at 50 °C, denoted in red color (Table 1.2). 1 Figure A.24 H NMR spectrum of the above reaction in C6D6 (Table 1.2). 100 A 1.15 29 13 Figure A.25 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 19 hours plus 25 hours at 50 °C, denoted in red color (Table 1.2). 1 Figure A.26 H NMR spectrum of the above reaction in C6D6 (Table 1.2). 101 A 1.16 29 13 Figure A.27 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 17 hours plus 9 hours at 50 °C, denoted in red color (Table 1.2). 1 Figure A.28 H NMR spectrum of the above reaction in C6D6 (Table 1.2). 102 A 1.17 29 13 Figure A.29 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 18.5 hours plus 3.5 hours at 50 °C, denoted in red color (Table 1.2). 1 Figure A.30 H NMR spectrum of the above reaction in C6D6 (Table 1.2). 103 A 1.18 29 13 Figure A.31 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 18.5 hours plus 14 hours at 50 °C, denoted in red color (Table 1.2). 1 Figure A.32 H NMR spectrum of the above reaction in C6D6 (Table 1.2). 104 A 1.19 29 13 Figure A.33 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature for 17 hours plus 23 hours at 50 °C, denoted in red color (Table 1.2) 1 Figure A.34 H NMR spectrum of the above reaction in C6D6 (Table 1.2). 105 A 1.20 29 13 Figure A.35 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature (Table 1.3). 1 Figure A.36 H NMR spectrum of the above reaction in C6D6 (Table 1.3). 106 A 1.21 29 13 Figure A.37 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 50 °C (Table 1.3). 1 Figure A.38 H NMR spectrum of the above reaction in C6D6 (Table 1.3). 107 A 1.22 29 13 Figure A.39 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 90 °C (Table 1.5, entry 4). A 1.23 29 13 Figure A.40 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 90 °C (Table 1.5, entry 5). 108 A 1.24 29 13 Figure A.41 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 90 °C (Table 1.5, entry 6). A 1.25 29 13 Figure A.42 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 50 °C (Table 1.6, entry 2). 109 A 1.26 29 13 Figure A.43 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature (Table 1.6, entry 3). A 1.27 29 13 Figure A.44 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 50 °C (Table 1.6, entry 4). 110 A 1.28 29 13 Figure A.45 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature (Table 1.6, entry 5) A 1.29 29 13 Figure A.46 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at 50 °C (Table 1.6, entry 6). 111 A 1.30 29 13 Figure A.47 Si NMR (left) and C NMR (right) monitoring of the above reaction in C6D6 at room temperature (Table 1.6, entry 7). A 1.31 13 Figure A.48 C NMR spectrum of (chloromethylene)dimethyliminium chloride in CDCl3. 112 A 1.32 29 13 Figure A.49 Si NMR (left) and C NMR (right) spectra of Me3SiI in C6D6. A 1.33 1 Figure A.50 H NMR spectrum of the above reaction at room temperature in C6D6 (Fig. 1.11). 113 A 1.34 1 Figure A.51 H NMR spectrum of the above reaction at room temperature in C6D6 (Fig. 1.12). 114 Chapter 2 A 2.1 MeOCH2NMe2, 2a. 13 Figure A.52 C NMR spectrum of MeOCH2NMe2, 2a, in C6D6. 1 Figure A.53 H NMR spectrum of MeOCH2NMe2, 2a, in C6D6. 115 13 Figure A.54 C NMR spectrum the above reaction to form MeOCH2NMe2, 2a, in C6D6. 116 A 2.2 EtOCH2NMe2, 2b. 13 Figure A.55 C NMR spectrum of EtOCH2NMe2, 2b, in C6D6. 1 Figure A.56 H NMR spectrum of EtOCH2NMe2, 2b, in C6D6. 117 13 Figure A.57 C NMR spectrum the above reaction to form EtOCH2NMe2, 2b, in C6D6. 118 i A 2.3 PrOCH2NMe2, 2c. 13 i Figure A.58 C NMR spectrum of PrOCH2NMe2, 2c, in C6D6. 1 i Figure A.59 H NMR spectrum of PrOCH2NMe2, 2c, in C6D6. 119 A 2.4 2-((dimethylamino)methyl)phenol, 2e. 13 Figure A.60 C NMR spectrum of 2-((dimethylamino)methyl)phenol, 2e, in CDCl3. 1 Figure A.61 H NMR spectrum of 2-((dimethylamino)methyl)phenol, 2e, in CDCl3. 120 A 2.5 4-((dimethylamino)methyl)-2,6-dimethylphenol, 2f. 13 Figure A.62 C NMR spectrum of 4-((dimethylamino)methyl)-2,6-dimethylphenol, 2f, in CDCl3. 1 Figure A.63 H NMR spectrum of 4-((dimethylamino)methyl)-2,6-dimethylphenol, 2f, in CDCl3. 121 Figure A.64 Single X-Ray crystal structure of 2,6-dimethyl-4-dimethylaminomethyl phenol, 2f. A specimen of C11H17NO was used for the X-ray crystallographic analysis. The X-ray intensity data were measured on a Bruker SMART APEX CCD system equipped with a graphite monochromator and a MoKα fine-focus tube (λ = 0.71073 Å). The total exposure time was 12.00 hours. The frames were integrated with the Bruker SAINT software package using a narrow-frame algorithm. The integration of the data using an orthorhombic unit cell yielded a total of 11150 reflections to a maximum θ angle of 27.00° (0.78 Å resolution), of which 2336 were independent (average redundancy 4.773, completeness = 2 98.8%, Rint = 4.87%, Rsig = 3.54%) and 1641 (70.25%) were greater than 2σ(F ). The final cell constants of a = 8.063(8) Å, b = 11.057(10) Å, c = 12.142(12) Å, volume = 1082.5(18) Å3, are based upon the refinement of the XYZ-centroids of 2484 reflections above 20 σ(I) with 4.982° < 2θ < 52.90°. Data were corrected for absorption effects using the multi-scan method (SADABS). The ratio of minimum to maximum apparent transmission was 0.893. The structure was solved and refined using the Bruker SHELXTL Software Package, using the space group P 21 21 21, with Z = 4 for the formula unit, C11H17NO. The final anisotropic full- matrix least-squares refinement on F2 with 127 variables converged at R1 = 4.31%, for the observed data and wR2 = 11.77% for all data. The goodness-of-fit was 1.023. The largest peak in the final difference electron density synthesis was 0.107 e-/Å3 and the largest hole was -0.092 e- 122 /Å3 with an RMS deviation of 0.025 e-/Å3. On the basis of the final model, the calculated density was 1.100 g/cm3 and F(000), 392 e-. Table A.4 Sample and crystal data for 2f (1085KPPG). Identification code 1085KPPG Chemical formula C11H17NO Formula weight 179.25 g/mol Temperature 298(2) K Wavelength 0.71073 Å Crystal system orthorhombic Space group P 21 21 21 Unit cell dimensions a = 8.063(8) Å α = 90° b = 11.057(10) Å β = 90° c = 12.142(12) Å γ = 90° Volume 1082.5(18) Å3 Z 4 Density (calculated) 1.100 g/cm3 Absorption coefficient 0.070 mm-1 F(000) 392 Table A.5 Data collection and structure refinement for 2f (1085KPPG). Diffractometer Bruker SMART APEX CCD Radiation source fine-focus tube, MoKα Theta range for data collection 2.49 to 27.00° Index ranges -8<=h<=10, -13<=k<=11, -15<=l<=15 Reflections collected 11150 Independent reflections 2336 [R(int) = 0.0487] Coverage of independent reflections 98.8% Absorption correction multi-scan Structure solution technique direct methods Structure solution program Bruker SAINT Refinement method Full-matrix least-squares on F2 Refinement program SHELXL-2014/6 (Sheldrick, 2014) 2 2 2 Function minimized Σ w(Fo - Fc ) Data / restraints / parameters 2336 / 0 / 127 Goodness-of-fit on F2 1.023 Final R indices 1641 data; I>2σ(I) R1 = 0.0431, wR2 = 0.1003 all data R1 = 0.0700, wR2 = 0.1177 2 2 2 w=1/[σ (Fo )+(0.0563P) +0.0413P] Weighting scheme 2 2 where P=(Fo +2Fc )/3 Absolute structure parameter 1.0(30) Largest diff. peak and hole 0.107 and -0.092 eÅ-3 R.M.S. deviation from mean 0.025 eÅ-3 123 Table A.6 . Bond lengths (Å) for 2f (1085KPPG). N1-C10 1.448(4) N1-C9 1.468(4) N1-C8 1.471(3) O1-C1 1.371(3) O1-H1O 0.89(4) C1-C2 1.390(4) C1-C6 1.396(4) C2-C3 1.381(4) C2-C7 1.508(4) C3-C4 1.383(4) C3-H3 0.93 C4-C5 1.389(4) C4-C8 1.505(4) C5-C6 1.381(4) C5-H5 0.93 C6-C11 1.501(4) C7-H7A 0.96 C7-H7B 0.96 C7-H7C 0.96 C8-H8A 0.97 C8-H8B 0.97 C9-H9A 0.96 C9-H9B 0.96 C9-H9C 0.96 C10-H10A 0.96 C10-H10B 0.96 C10-H10C 0.96 C11-H11A 0.96 C11-H11B 0.96 C11-H11C 0.96 Table A.7 Bond angles (°) for 2f (1085KPPG). C10-N1-C9 110.2(2) C10-N1-C8 110.7(2) C9-N1-C8 109.1(2) C1-O1-H1O 113.(2) O1-C1-C2 121.3(2) O1-C1-C6 117.8(2) C2-C1-C6 120.9(2) C3-C2-C1 118.0(3) C3-C2-C7 121.6(3) C1-C2-C7 120.4(3) C2-C3-C4 123.1(3) C2-C3-H3 118.5 C4-C3-H3 118.5 C3-C4-C5 117.4(2) C3-C4-C8 121.3(3) C5-C4-C8 121.3(2) C6-C5-C4 121.8(2) C6-C5-H5 119.1 C4-C5-H5 119.1 C5-C6-C1 118.9(2) C5-C6-C11 121.2(2) C1-C6-C11 119.8(2) C2-C7-H7A 109.5 C2-C7-H7B 109.5 H7A-C7-H7B 109.5 C2-C7-H7C 109.5 H7A-C7-H7C 109.5 H7B-C7-H7C 109.5 N1-C8-C4 113.7(2) N1-C8-H8A 108.8 C4-C8-H8A 108.8 N1-C8-H8B 108.8 C4-C8-H8B 108.8 H8A-C8-H8B 107.7 N1-C9-H9A 109.5 N1-C9-H9B 109.5 H9A-C9-H9B 109.5 N1-C9-H9C 109.5 H9A-C9-H9C 109.5 H9B-C9-H9C 109.5 N1-C10-H10A 109.5 N1-C10-H10B 109.5 H10A-C10-H10B 109.5 N1-C10-H10C 109.5 H10A-C10-H10C 109.5 H10B-C10-H10C 109.5 C6-C11-H11A 109.5 C6-C11-H11B 109.5 H11A-C11-H11B 109.5 C6-C11-H11C 109.5 H11A-C11-H11C 109.5 H11B-C11-H11C 109.5 124 Table A. 8 Torsion angles (°) for 2f (1085KPPG). O1-C1-C2-C3 -178.0(2) C6-C1-C2-C3 -0.6(3) O1-C1-C2-C7 0.7(4) C6-C1-C2-C7 178.0(2) C1-C2-C3-C4 -0.2(4) C7-C2-C3-C4 -178.8(2) C2-C3-C4-C5 0.4(4) C2-C3-C4-C8 -179.3(2) C3-C4-C5-C6 0.1(3) C8-C4-C5-C6 179.9(2) C4-C5-C6-C1 -0.9(3) C4-C5-C6-C11 -179.7(2) O1-C1-C6-C5 178.6(2) C2-C1-C6-C5 1.1(3) O1-C1-C6-C11 -2.5(3) C2-C1-C6-C11 -180.0(2) C10-N1-C8-C4 60.5(3) C9-N1-C8-C4 -178.0(2) C3-C4-C8-N1 69.7(3) C5-C4-C8-N1 -110.0(3) A 2.6 2,4-bis[(dimethylamino)methyl]-1-naphthalenol, 2i. 13 Figure A.65 C NMR spectrum of 2,4-bis[(dimethylamino)methyl]-1-naphthalenol, 2i, in CDCl3. 125 13 Figure A.66 C DEPT135 NMR spectrum of 2,4-bis[(dimethylamino)methyl]-1-naphthalenol, 2i, in CDCl3. 1 Figure A.67 H NMR spectrum of 2,4-bis[(dimethylamino)methyl]-1-naphthalenol, 2i, in CDCl3. 126 Figure A.68 13C NMR spectrum the above reaction to form 2,4-bis[(dimethylamino)methyl]-1-naphthalenol, 2i, in CDCl3. Figure A.69 Single X-Ray crystal structure of 2,4-bis[(dimethylamino)methyl]-1-naphthalenol, 2i. 127 A specimen of C16H22N2O was used for the X-ray crystallographic analysis. The X-ray intensity data were measured on a Bruker SMART APEX CCD system equipped with a graphite monochromator and a MoKα fine-focus tube (λ = 0.71073 Å). The total exposure time was 10.00 hours. The frames were integrated with the Bruker SAINT software package using a narrow-frame algorithm. The integration of the data using an orthorhombic unit cell yielded a total of 34714 reflections to a maximum θ angle of 30.16° (0.71 Å resolution), of which 4271 were independent (average redundancy 8.128, completeness = 2 98.5%, Rint = 4.46%, Rsig = 3.07%) and 2968 (69.49%) were greater than 2σ(F ). The final cell constants of a = 14.4069(9) Å, b = 10.4989(7) Å, c = 19.3631(13) Å, volume = 2928.8(3) Å3, are based upon the refinement of the XYZ-centroids of 6021 reflections above 20 σ(I) with 5.069° < 2θ < 59.48°. Data were corrected for absorption effects using the multi-scan method (SADABS). The ratio of minimum to maximum apparent transmission was 0.893. The structure was solved and refined using the Bruker SHELXTL Software Package, using the space group P b c a, with Z = 8 for the formula unit, C16H22N2O. The final anisotropic full- matrix least-squares refinement on F2 with 180 variables converged at R1 = 4.84%, for the observed data and wR2 = 15.76% for all data. The goodness-of-fit was 0.950. The largest peak in the final difference electron density synthesis was 0.372 e-/Å3 and the largest hole was -0.168 e- /Å3 with an RMS deviation of 0.046 e-/Å3. On the basis of the final model, the calculated density was 1.172 g/cm3 and F(000), 1120 e-. Table A.9 Sample and crystal data for 2i (1247KP). Identification code 1247KP Chemical formula C16H22N2O Formula weight 258.35 g/mol Temperature 150(2) K Wavelength 0.71073 Å Crystal system orthorhombic Space group P b c a Unit cell dimensions a = 14.4069(9) Å α = 90° b = 10.4989(7) Å β = 90° c = 19.3631(13) Å γ = 90° Volume 2928.8(3) Å3 128 Z 8 Density (calculated) 1.172 g/cm3 Absorption coefficient 0.074 mm-1 F(000) 1120 Table A.10 Data collection and structure refinement for 2i (1247KP). Diffractometer Bruker SMART APEX CCD Radiation source fine-focus tube, MoKα Theta range for data collection 2.10 to 30.16° Index ranges -18<=h<=20, -14<=k<=14, -27<=l<=26 Reflections collected 34714 Independent reflections 4271 [R(int) = 0.0446] Coverage of independent reflections 98.5% Absorption correction multi-scan Structure solution technique direct methods Structure solution program SHELXS-97(Sheldrick 2008) Refinement method Full-matrix least-squares on F2 Refinement program SHELXL-2014/6 (Sheldrick, 2014) 2 2 2 Function minimized Σ w(Fo - Fc ) Data / restraints / parameters 4271 / 0 / 180 Goodness-of-fit on F2 0.950 Final R indices 2968 data; I>2σ(I) R1 = 0.0484, wR2 = 0.1312 all data R1 = 0.0785, wR2 = 0.1576 2 2 2 w=1/[σ (Fo )+(0.1000P) +0.3974P] Weighting scheme 2 2 where P=(Fo +2Fc )/3 Largest diff. peak and hole 0.372 and -0.168 eÅ-3 R.M.S. deviation from mean 0.046 eÅ-3 Table A.11 Bond lengths (Å) for 2i (1247KP). O1-C1 1.3676(15) O1-H1O 0.91(2) N2-C15 1.4529(18) N2-C16 1.4567(17) N2-C14 1.4675(17) N1-C13 1.4651(18) N1-C12 1.4676(17) N1-C11 1.4790(17) C10-C9 1.4186(17) C10-C1 1.4240(17) C10-C5 1.4251(18) C5-C6 1.4185(17) C5-C4 1.4353(17) C2-C1 1.3833(17) C2-C3 1.4097(18) C2-C11 1.5063(17) C4-C3 1.3701(17) C4-C14 1.5081(18) C3-H3 0.95 C6-C7 1.3718(18) C6-H6 0.95 C14-H14A 0.99 C14-H14B 0.99 C9-C8 1.3699(19) C9-H9 0.95 C11-H11A 0.99 C11-H11B 0.99 C7-C8 1.411(2) C7-H7 0.95 C8-H8 0.95 C13-H13A 0.98 C13-H13B 0.98 C13-H13C 0.98 C12-H12A 0.98 C12-H12B 0.98 C12-H12C 0.98 C15-H15A 0.98 C15-H15B 0.98 129 C15-H15C 0.98 C16-H16A 0.98 C16-H16B 0.98 C16-H16C 0.98 Table A.12 Bond angles (°) for 2i (1247KP). C1-O1-H1O 104.1(12) C15-N2-C16 110.30(12) C15-N2-C14 111.12(11) C16-N2-C14 110.19(11) C13-N1-C12 109.93(11) C13-N1-C11 110.30(11) C12-N1-C11 110.16(11) C9-C10-C1 121.12(12) C9-C10-C5 119.58(11) C1-C10-C5 119.30(11) C6-C5-C10 117.88(11) C6-C5-C4 122.84(12) C10-C5-C4 119.27(11) C1-C2-C3 118.82(11) C1-C2-C11 120.93(12) C3-C2-C11 120.22(11) O1-C1-C2 121.63(11) O1-C1-C10 117.58(11) C2-C1-C10 120.79(12) C3-C4-C5 118.77(12) C3-C4-C14 120.21(11) C5-C4-C14 121.01(11) C4-C3-C2 123.01(11) C4-C3-H3 118.5 C2-C3-H3 118.5 C7-C6-C5 121.37(13) C7-C6-H6 119.3 C5-C6-H6 119.3 N2-C14-C4 112.68(10) N2-C14-H14A 109.1 C4-C14-H14A 109.1 N2-C14-H14B 109.1 C4-C14-H14B 109.1 H14A-C14-H14B 107.8 C8-C9-C10 120.80(13) C8-C9-H9 119.6 C10-C9-H9 119.6 N1-C11-C2 112.12(10) N1-C11-H11A 109.2 C2-C11-H11A 109.2 N1-C11-H11B 109.2 C2-C11-H11B 109.2 H11A-C11-H11B 107.9 C6-C7-C8 120.40(12) C6-C7-H7 119.8 C8-C7-H7 119.8 C9-C8-C7 119.96(12) C9-C8-H8 120.0 C7-C8-H8 120.0 N1-C13-H13A 109.5 N1-C13-H13B 109.5 H13A-C13-H13B 109.5 N1-C13-H13C 109.5 H13A-C13-H13C 109.5 H13B-C13-H13C 109.5 N1-C12-H12A 109.5 N1-C12-H12B 109.5 H12A-C12-H12B 109.5 N1-C12-H12C 109.5 H12A-C12-H12C 109.5 H12B-C12-H12C 109.5 N2-C15-H15A 109.5 N2-C15-H15B 109.5 H15A-C15-H15B 109.5 N2-C15-H15C 109.5 H15A-C15-H15C 109.5 H15B-C15-H15C 109.5 N2-C16-H16A 109.5 N2-C16-H16B 109.5 H16A-C16-H16B 109.5 N2-C16-H16C 109.5 H16A-C16 -H16C 109.5 H16B-C16-H16C 109.5 Table A.13 Torsion angles (°) for 2i (1247KP). C9-C10-C5-C6 0.76(17) C1-C10-C5-C6 -178.69(11) C9-C10-C5-C4 -179.42(11) C1-C10-C5-C4 1.13(17) C3-C2-C1-O1 -179.81(11) C11-C2-C1-O1 -1.83(19) C3-C2-C1-C10 -0.26(18) C11-C2-C1-C10 177.71(11) C9-C10-C1-O1 -0.99(18) C5-C10-C1-O1 178.46(11) 130 C9-C10-C1-C2 179.45(12) C5-C10-C1-C2 -1.11(18) C6-C5-C4-C3 -179.97(11) C10-C5-C4-C3 0.22(17) C6-C5-C4-C14 0.05(18) C10-C5-C4-C14 -179.76(11) C5-C4-C3-C2 -1.67(18) C14-C4-C3-C2 178.31(11) C1-C2-C3-C4 1.71(19) C11-C2-C3-C4 -176.28(11) C10-C5-C6-C7 -1.10(18) C4-C5-C6-C7 179.09(12) C15-N2-C14-C4 69.72(14) C16-N2-C14-C4 -167.72(12) C3-C4-C14-N2 -106.90(13) C5-C4-C14-N2 73.08(15) C1-C10-C9-C8 179.18(13) C5-C10-C9-C8 -0.27(19) C13-N1-C11-C2 64.18(14) C12-N1-C11-C2 -174.28(11) C1-C2-C11-N1 39.88(17) C3-C2-C11-N1 -142.17(12) C5-C6-C7-C8 0.9(2) C10-C9-C8-C7 0.1(2) C6-C7-C8-C9 -0.4(2) A 2.7 1-[(dimethylamino)methyl]-2-naphthalenol, 2h. Figure A.70 13C NMR spectrum the above reaction to form 1-[(dimethylamino)methyl]-2-naphthalenol, 2h, in CDCl3. 131 A 2.8 Cholesteromethyl(dimethyl)amine, 2j. 13 13 Figure A.71 a) C NMR spectrum of Cholesterol (starting material) in C6D6. b) C NMR spectrum of Cholesteromethyl(dimethyl)amine, 2j, in C6D6; the green arrows indicate the new peaks: methylene 13 (O-CH2-N) at 87.5 ppm and dimethylamine (N(CH3)2) at 41.7 ppm. c) C DEPT135 NMR spectrum of Cholesteromethyl(dimethyl)amine, 2j, in C6D6. 132 1 Figure A.72 H NMR spectrum of Cholesteromethyl(dimethyl)amine, 2j, in C6D6. Figure A.73 Single X-Ray crystal structure of Cholesteromethyl(dimethyl)amine, 2j. A specimen of C30H53NO was used for the X-ray crystallographic analysis. The X-ray intensity data were measured on a Bruker SMART APEX CCD system equipped with a graphite monochromator and a MoKα fine-focus tube (λ = 0.71073 Å). The total exposure time was 10.58 hours. The frames were integrated with the Bruker SAINT software package using a narrow-frame algorithm. The integration of the data using a monoclinic unit cell yielded a total of 5486 reflections to a maximum θ angle of 22.71° (0.92 Å 133 resolution), of which 2228 were independent (average redundancy 2.462, completeness = 91.5%, 2 Rint = 4.18%, Rsig = 5.34%) and 1877 (84.25%) were greater than 2σ(F ). The final cell constants of a = 12.659(18) Å, b = 9.010(13) Å, c = 12.836(18) Å, β = 110.51(2)°, volume = 1371.(3) Å3, are based upon the refinement of the XYZ-centroids of 1655 reflections above 20 σ(I) with 5.607° < 2θ < 40.70°. Data were corrected for absorption effects using the multi-scan method (SADABS). The ratio of minimum to maximum apparent transmission was 0.728. The structure was solved and refined using the Bruker SHELXTL Software Package, using the space group P 1 21 1, with Z = 2 for the formula unit, C30H53NO. The final anisotropic full- matrix least-squares refinement on F2 with 294 variables converged at R1 = 4.31%, for the observed data and wR2 = 10.57% for all data. The goodness-of-fit was 1.021. The largest peak in the final difference electron density synthesis was 0.149 e-/Å3 and the largest hole was -0.180 e- /Å3 with an RMS deviation of 0.040 e-/Å3. On the basis of the final model, the calculated density was 1.075 g/cm3 and F(000), 496 e-. Table A. 14 Sample and crystal data for 2j (976KP). Identification code 976KP Chemical formula C30H53NO Formula weight 443.73 g/mol Temperature 296(2) K Wavelength 0.71073 Å Crystal system monoclinic Space group P 1 21 1 Unit cell dimensions a = 12.659(18) Å α = 90° b = 9.010(13) Å β = 110.51(2)° c = 12.836(18) Å γ = 90° Volume 1371.(3) Å3 Z 2 Density (calculated) 1.075 g/cm3 Absorption coefficient 0.063 mm-1 F(000) 496 Table A.15 Data collection and structure refinement for 2j (976KP). Diffractometer Bruker SMART APEX CCD Radiation source fine-focus tube, MoKα Theta range for data collection 1.69 to 22.71° 134 Index ranges -13<=h<=13, -9<=k<=3, -13<=l<=13 Reflections collected 5486 Independent reflections 2228 [R(int) = 0.0418] Coverage of independent reflections 91.5% Absorption correction multi-scan Structure solution technique direct methods Structure solution program Bruker SAINT Refinement method Full-matrix least-squares on F2 Refinement program SHELXL-2014 (Sheldrick, 2014) 2 2 2 Function minimized Σ w(Fo - Fc ) Data / restraints / parameters 2228 / 1 / 294 Goodness-of-fit on F2 1.021 Final R indices 1877 data; I>2σ(I) R1 = 0.0431, wR2 = 0.0984 all data R1 = 0.0555, wR2 = 0.1057 2 2 2 2 2 Weighting scheme w=1/[σ (Fo )+(0.0642P) ] where P=(Fo +2Fc )/3 Absolute structure parameter 4.0(10) Largest diff. peak and hole 0.149 and -0.180 eÅ-3 R.M.S. deviation from mean 0.040 eÅ-3 Table A.16 Bond lengths (Å) for 2j (976KP). N1-C28 1.429(6) N1-C30 1.439(6) N1-C29 1.458(7) O1-C28 1.433(5) O1-C3 1.435(5) C1-C2 1.525(5) C1-C10 1.550(6) C1-H1A 0.97 C1-H1B 0.97 C2-C3 1.512(5) C2-H2A 0.97 C2-H2B 0.97 C3-C4 1.514(6) C3-H3 0.98 C4-C5 1.522(5) C4-H4A 0.97 C4-H4B 0.97 C5-C6 1.319(5) C5-C10 1.519(5) C6-C7 1.491(5) C6-H6 0.93 C7-C8 1.537(5) C7-H7A 0.97 C7-H7B 0.97 C8-C14 1.530(5) C8-C9 1.541(6) C8-H8 0.98 C9-C11 1.544(5) C9-C10 1.555(5) C9-H9 0.98 C10-C19 1.529(6) C11-C12 1.540(5) C11-H11A 0.97 C11-H11B 0.97 C12-C13 1.536(6) C12-H12A 0.97 C12-H12B 0.97 C13-C18 1.534(6) C13-C14 1.541(5) C13-C17 1.551(5) C14-C15 1.524(6) C14-H14 0.98 C15-C16 1.548(5) C15-H15A 0.97 C15-H15B 0.97 C16-C17 1.551(6) C16-H16A 0.97 C16-H16B 0.97 C17-C20 1.549(5) C17-H17 0.98 C18-H18A 0.96 C18-H18B 0.96 C18-H18C 0.96 C19-H19A 0.96 C19-H19B 0.96 C19-H19C 0.96 C20-C21 1.535(6) C20-C22 1.537(6) C20-H20 0.98 C21-H21A 0.96 C21-H21B 0.96 C21-H21C 0.96 135 C22-C23 1.533(5) C22-H22A 0.97 C22-H22B 0.97 C23-C24 1.525(6) C23-H23A 0.97 C23-H23B 0.97 C24-C25 1.527(6) C24-H24A 0.97 C24-H24B 0.97 C25-C26 1.517(8) C25-C27 1.534(6) C25-H25 0.98 C26-H26A 0.96 C26-H26B 0.96 C26-H26C 0.96 C27-H27A 0.96 C27-H27B 0.96 C27-H27C 0.96 C28-H28A 0.97 C28-H28B 0.97 C29-H29A 0.96 C29-H29B 0.96 C29-H29C 0.96 C30-H30A 0.96 C30-H30B 0.96 C30-H30C 0.96 Table A.17 Bond angles (°) for 2j (976KP). C28-N1-C30 112.5(4) C28-N1-C29 111.7(4) C30-N1-C29 111.4(5) C28-O1-C3 114.8(4) C2-C1-C10 114.3(3) C2-C1-H1A 108.7 C10-C1-H1A 108.7 C2-C1-H1B 108.7 C10-C1-H1B 108.7 H1A-C1-H1B 107.6 C3-C2-C1 109.9(3) C3-C2-H2A 109.7 C1-C2-H2A 109.7 C3-C2-H2B 109.7 C1-C2-H2B 109.7 H2A-C2-H2B 108.2 O1-C3-C2 112.4(3) O1-C3-C4 105.9(3) C2-C3-C4 110.5(3) O1-C3-H3 109.3 C2-C3-H3 109.3 C4-C3-H3 109.3 C3-C4-C5 112.3(3) C3-C4-H4A 109.2 C5-C4-H4A 109.2 C3-C4-H4B 109.2 C5-C4-H4B 109.2 H4A-C4-H4B 107.9 C6-C5-C10 123.1(3) C6-C5-C4 120.6(3) C10-C5-C4 116.3(4) C5-C6-C7 125.5(3) C5-C6-H6 117.3 C7-C6-H6 117.3 C6-C7-C8 112.2(3) C6-C7-H7A 109.2 C8-C7-H7A 109.2 C6-C7-H7B 109.2 C8-C7-H7B 109.2 H7A-C7-H7B 107.9 C14-C8-C7 110.6(3) C14-C8-C9 109.8(3) C7-C8-C9 109.9(3) C14-C8-H8 108.8 C7-C8-H8 108.8 C9-C8-H8 108.8 C8-C9-C11 112.5(3) C8-C9-C10 111.2(3) C11-C9-C10 113.7(3) C8-C9-H9 106.3 C11-C9-H9 106.3 C10-C9-H9 106.3 C5-C10-C19 109.6(4) C5-C10-C1 108.6(3) C19-C10-C1 108.4(4) C5-C10-C9 109.9(3) C19-C10-C9 111.7(3) C1-C10-C9 108.5(3) C12-C11-C9 113.5(3) C12-C11-H11A 108.9 C9-C11-H11A 108.9 C12-C11-H11B 108.9 C9-C11-H11B 108.9 H11A-C11-H11B 107.7 C13-C12-C11 111.5(3) C13-C12-H12A 109.3 C11-C12-H12A 109.3 C13-C12-H12B 109.3 C11-C12-H12B 109.3 H12A-C12-H12B 108.0 C18-C13-C12 110.7(4) C18-C13-C14 112.9(3) 136 C12-C13-C14 106.0(3) C18-C13-C17 110.4(3) C12-C13-C17 116.4(4) C14-C13-C17 100.2(3) C15-C14-C8 117.3(3) C15-C14-C13 103.4(3) C8-C14-C13 115.0(3) C15-C14-H14 106.8 C8-C14-H14 106.8 C13-C14-H14 106.8 C14-C15-C16 103.1(3) C14-C15-H15A 111.1 C16-C15-H15A 111.1 C14-C15-H15B 111.1 C16-C15-H15B 111.1 H15A-C15-H15B 109.1 C15-C16-C17 107.2(3) C15-C16-H16A 110.3 C17-C16-H16A 110.3 C15-C16-H16B 110.3 C17-C16-H16B 110.3 H16A-C16-H16B 108.5 C20-C17-C16 111.7(3) C20-C17-C13 118.5(3) C16-C17-C13 103.3(3) C20-C17-H17 107.6 C16-C17-H17 107.6 C13-C17-H17 107.6 C13-C18-H18A 109.5 C13-C18-H18B 109.5 H18A-C18-H18B 109.5 C13-C18-H18C 109.5 H18A-C18-H18C 109.5 H18B-C18-H18C 109.5 C10-C19-H19A 109.5 C10-C19-H19B 109.5 H19A-C19-H19B 109.5 C10-C19-H19C 109.5 H19A-C19-H19C 109.5 H19B-C19-H19C 109.5 C21-C20-C22 109.7(4) C21-C20-C17 112.5(3) C22-C20-C17 109.8(3) C21-C20-H20 108.2 C22-C20-H20 108.2 C17-C20-H20 108.2 C20-C21-H21A 109.5 C20-C21-H21B 109.5 H21A-C21-H21B 109.5 C20-C21-H21C 109.5 H21A-C21-H21C 109.5 H21B-C21-H21C 109.5 C23-C22-C20 114.4(4) C23-C22-H22A 108.7 C20-C22-H22A 108.7 C23-C22-H22B 108.7 C20-C22-H22B 108.7 H22A-C22-H22B 107.6 C24-C23-C22 111.5(4) C24-C23-H23A 109.3 C22-C23-H23A 109.3 C24-C23-H23B 109.3 C22-C23-H23B 109.3 H23A-C23-H23B 108.0 C23-C24-C25 115.8(4) C23-C24-H24A 108.3 C25-C24-H24A 108.3 C23-C24-H24B 108.3 C25-C24-H24B 108.3 H24A-C24-H24B 107.4 C26-C25-C24 113.2(4) C26-C25-C27 111.0(4) C24-C25-C27 110.1(4) C26-C25-H25 107.5 C24-C25-H25 107.5 C27-C25-H25 107.5 C25-C26-H26A 109.5 C25-C26-H26B 109.5 H26A-C26-H26B 109.5 C25-C26-H26C 109.5 H26A-C26-H26C 109.5 H26B-C26-H26C 109.5 C25-C27-H27A 109.5 C25-C27-H27B 109.5 H27A-C27-H27B 109.5 C25-C27-H27C 109.5 H27A-C27-H27C 109.5 H27B-C27-H27C 109.5 N1-C28-O1 110.6(4) N1-C28-H28A 109.5 O1-C28-H28A 109.5 N1-C28-H28B 109.5 O1-C28-H28B 109.5 H28A-C28-H28B 108.1 N1-C29-H29A 109.5 N1-C29-H29B 109.5 H29A-C29-H29B 109.5 N1-C29-H29C 109.5 H29A-C29-H29C 109.5 H29B-C29-H29C 109.5 N1-C30-H30A 109.5 N1-C30-H30B 109.5 H30A-C30-H30B 109.5 N1-C30-H30C 109.5 H30A-C30-H30C 109.5 H30B-C30-H30C 109.5 137 Table A.18 Torsion angles (°) for 2j (976KP). C10-C1-C2-C3 -57.8(5) C28-O1-C3-C2 69.6(5) C28-O1-C3-C4 -169.7(4) C1-C2-C3-O1 176.3(4) C1-C2-C3-C4 58.2(5) O1-C3-C4-C5 -176.6(4) C2-C3-C4-C5 -54.6(5) C3-C4-C5-C6 -131.9(4) C3-C4-C5-C10 50.5(5) C10-C5-C6-C7 0.2(7) C4-C5-C6-C7 -177.3(4) C5-C6-C7-C8 12.7(6) C6-C7-C8-C14 -163.8(4) C6-C7-C8-C9 -42.4(5) C14-C8-C9-C11 -47.7(5) C7-C8-C9-C11 -169.6(3) C14-C8-C9-C10 -176.6(3) C7-C8-C9-C10 61.6(5) C6-C5-C10-C19 -105.7(5) C4-C5-C10-C19 71.9(4) C6-C5-C10-C1 136.0(4) C4-C5-C10-C1 -46.4(5) C6-C5-C10-C9 17.4(6) C4-C5-C10-C9 -165.0(4) C2-C1-C10-C5 50.3(5) C2-C1-C10-C19 -68.7(4) C2-C1-C10-C9 169.8(3) C8-C9-C10-C5 -47.7(5) C11-C9-C10-C5 -175.9(3) C8-C9-C10-C19 74.2(4) C11-C9-C10-C19 -54.0(5) C8-C9-C10-C1 -166.4(3) C11-C9-C10-C1 65.4(4) C8-C9-C11-C12 49.0(5) C10-C9-C11-C12 176.5(4) C9-C11-C12-C13 -55.2(5) C11-C12-C13-C18 -64.6(4) C11-C12-C13-C14 58.1(5) C11-C12-C13-C17 168.4(3) C7-C8-C14-C15 -60.0(5) C9-C8-C14-C15 178.5(3) C7-C8-C14-C13 178.0(3) C9-C8-C14-C13 56.6(5) C18-C13-C14-C15 -69.1(4) C12-C13-C14-C15 169.6(4) C17-C13-C14-C15 48.2(4) C18-C13-C14-C8 60.1(5) C12-C13-C14-C8 -61.2(5) C17-C13-C14-C8 177.5(4) C8-C14-C15-C16 -165.3(3) C13-C14-C15-C16 -37.5(4) C14-C15-C16-C17 12.2(5) C15-C16-C17-C20 145.7(3) C15-C16-C17-C13 17.2(4) C18-C13-C17-C20 -44.3(5) C12-C13-C17-C20 82.9(5) C14-C13-C17-C20 -163.5(4) C18-C13-C17-C16 79.8(4) C12-C13-C17-C16 -153.0(3) C14-C13-C17-C16 -39.3(4) C16-C17-C20-C21 -176.8(4) C13-C17-C20-C21 -56.9(5) C16-C17-C20-C22 60.8(5) C13-C17-C20-C22 -179.4(4) C21-C20-C22-C23 69.7(5) C17-C20-C22-C23 -166.2(4) C20-C22-C23-C24 177.3(4) C22-C23-C24-C25 170.4(4) C23-C24-C25-C26 57.8(6) C23-C24-C25-C27 -177.4(4) C30-N1-C28-O1 -63.6(6) C29-N1-C28-O1 62.5(5) C3-O1-C28-N1 149.8(4) 138 A 2.9 EtSCH2NMe2, 3a. 13 Figure A.74 C NMR spectrum of EtSCH2NMe2, 3a, in C6D6 (Table 2.1, entry 1). 1 Figure A.75 H NMR spectrum of EtSCH2NMe2, 3a, in C6D6 (Table 2.1, entry 1). 139 A 2.10 PrSCH2NMe2, 3b. 13 Figure A.76 C NMR spectrum of PrSCH2NMe2, 3b, in C6D6 (Table 2.1, entry 3). 1 Figure A.77 H NMR spectrum of PrSCH2NMe2, 3b, in C6D6 (Table 2.1, entry 3). 140 13 Figure A.78 C NMR spectrum the above reaction to form PrSCH2NMe2, 3b, in C6D6 (Table 2.1, entry 2). 141 A 2.11 BuSCH2NMe2, 3c. 13 Figure A.79 C NMR spectrum of BuSCH2NMe2, 3c, in C6D6 (Table 2.1, entry 5). 1 Figure A.80 H NMR spectrum of BuSCH2NMe2, 3c, in C6D6 (Table 2.1, entry 5). 142 Figure A.81 Mass spectrum (ESI+) for BuSCH2NMe2, 3c (Table 2.1, entry 5). 13 Figure A.82 C NMR spectrum the above reaction to form BuSCH2NMe2, 3c, in C6D6 (Table 2.1, entry 4). 143 A 2.12 N,N-dimethyl-1-(phenylthio)methanamine, 3d. 13 Figure A.83 C NMR spectrum of N,N-dimethyl-1-(phenylthio)methanamine, 3d, in C6D6. 144 13 Figure A.84 C DEPT135 NMR spectrum of N,N-dimethyl-1-(phenylthio)methanamine, 3d, in C6D6. 1 Figure A.85 H NMR spectrum of N,N-dimethyl-1-(phenylthio)methanamine, 3d, in C6D6. 145 A 2.13 1-((2,6-dimethylphenyl)thio)-N,N-dimethylmethanamine, 3e. 13 Figure A.86 C NMR spectrum of 1-((2,6-dimethylphenyl)thio)-N,N-dimethylmethanamine, 3e, in CDCl3. 1 Figure A.87 H NMR spectrum of 1-((2,6-dimethylphenyl)thio)-N,N-dimethylmethanamine, 3e, in CDCl3. 146 Chapter 3 A 3.1 5a 1 Figure A.88 H NMR spectrum of 5a in CDCl3. 147 A 3.2 5b 13 Figure A.89 C NMR spectrum of 5b in CDCl3. 1 Figure A.90 H NMR spectrum of 5b in CDCl3. 148 A 3.3 1a 1 Figure A.91 H NMR spectrum of 1a in CDCl3. A 3.4 6a Figure A.92 Single X-Ray crystal structure of 6a. 149 The geometry of the Chromium is piano stool. The chloromethylene group in an anti- fashion with respect to the Cromium-arene. To our surprise the chloro is not participating in any interaction in the crystal structure, the groups that participate are the carbonyls attached to the chromium generating a HB network. 6 Table A.19 Crystal data of (η -C6H5)Cr(CO)3Me2SiCH2Cl (6a). Identification code 272PG Formula C12 H13 Cl Cr O3 Si Formula weight 320.76 Crystal System Orthorhombic Space Group Pca21 a 12.865(6) b 10.384(5) c 10.722(5) Volume (Å3) 1423.3(12) T (K) 150(2) Independent. refl. [Rint] 3459[0.048] Data/restraints/parameters 3459/1/165 R1 [I>2σ(I)] 0.0663 Density calculated (g/cm3) 1.487 6 Table A.20 Selected bonds (Å), bond angles (°) and torsion angles (°) for (η -C6H5)Cr(CO)3Me2SiCH2Cl (6a). Cr(1)-C(1) 2.231(5) Si(2)-C(1) 1.879(6) Cr(1)-C(2) 2.194(5) Cl(1)-C(10) 1.801(5) Cr(1)-C(3) 2.210(5) C(12)-Si(2)-C(11) 111.7(3) Cr(1)-C(4) 2.214(6) C(12)-Si(2)-C(10) 109.8(3) Cr(1)-C(5) 2.218(5) C(11)-Si(2)-C(10) 110.1(3) Cr(1)-C(6) 2.205(5) C(12)-Si(2)-C(1) 110.5(3) Cr(1)-C(7) 1.840(5) C(11)-Si(2)-C(1) 110.1(2) Cr(1)-C(8) 1.836(6) C(10)-Si(2)-C(1) 104.3(2) Cr(1)-C(9) 1.823(5) Cl(1)-C(10)-Si(2) 110.3(3) Si(2)-C(12) 1.846(6) C(10)-Si(2)-C(1)-C(2) -89.4(4) Si(2)-C(11) 1.850(6) C(10)-Si(2)-C(1)-C(6) 95.2(4) Si(2)-C(10) 1.878(6) C(1)-Si(2)-C(10)-Cl(1) 176.9(3) 150 1 Figure A.93 H NMR spectrum of 6a in CDCl3. A 3.5 6b 13 Figure A.94 C NMR spectrum of 6b in C6D6. 151 13 Figure A.95 C DEPT135 NMR spectrum of 6b in C6D6. 1 Figure A.96 H NMR spectrum of 6b in C6D6. 152 A 3.6 2a 1 Figure A.97 H NMR spectrum of 2a in C6D6. Figure A.98 Single X-Ray crystal structure of 2a. 153 Table A.21 Crystal data and structure refinement for 2a (369PG_0mS). Identification code 369pg_0ms Empirical formula C15 H22 Cr Ge O3 Si Formula weight 403.01 Temperature 296(2) K Wavelength 0.71073 Å Crystal system Triclinic Space group P-1 Unit cell dimensions a = 6.8776(17) Å = 81.711(4)° b = 6.8976(17) Å = 87.440(4)° c = 22.342(5) Å = 64.158(3)° Volume 943.7(4) Å3 Z 2 Density (calculated) 1.418 Mg/m3 Absorption coefficient 2.237 mm-1 F(000) 412 Crystal size 0.12 x 0.06 x 0.06 mm3 Theta range for data collection 1.84 to 27.00°. Index ranges -8<=h<=8, -8<=k<=8, -28<=l<=28 Reflections collected 13289 Independent reflections 4105 [R(int) = 0.0948] Completeness to theta = 27.00° 99.8 % Absorption correction Semi-empirical from equivalents Max. and min. transmission 0.8775 and 0.7751 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 4105 / 0 / 195 Goodness-of-fit on F2 0.846 Final R indices [I>2sigma(I)] R1 = 0.0557, wR2 = 0.1299 R indices (all data) R1 = 0.1583, wR2 = 0.1969 Largest diff. peak and hole 0.359 and -0.392 e.Å-3 Table A.22 Atomic coordinates ( x 104) and equivalent isotropic displacement parameters (Å2x 103) for 2a (369PG_0mS). U(eq) is defined as one third of the trace of the orthogonalized Uij tensor x y z U(eq) Cr(1) 4387(2) -859(2) 3792(1) 49(1) Si(1) 1116(3) 1379(3) 2348(1) 52(1) Ge(1) 3206(2) -513(2) 1082(1) 75(1) O(1) 7867(10) -4044(10) 4653(3) 104(2) O(2) 7572(9) -2419(11) 2817(3) 97(2) O(3) 6126(10) 2360(11) 3887(4) 114(2) C(1) 1468(10) 369(11) 3185(3) 50(2) C(2) 2072(11) -1849(11) 3425(3) 56(2) C(3) 2303(12) -2536(13) 4042(4) 68(2) C(4) 1993(11) -1099(15) 4454(3) 70(2) C(5) 1364(11) 1108(13) 4233(3) 63(2) C(6) 1087(10) 1803(12) 3615(3) 56(2) C(7) 2487(13) -981(12) 1924(3) 68(2) C(8) -1860(11) 2714(14) 2182(4) 83(3) 154 C(9) 2210(12) 3419(12) 2185(4) 72(2) C(10) 977(19) 2075(16) 636(4) 122(4) C(11) 3615(19) -3001(16) 709(4) 120(4) C(12) 5933(17) -284(18) 1054(5) 118(4) C(13) 6510(13) -2816(13) 4322(4) 69(2) C(14) 6282(11) -1812(12) 3186(3) 58(2) C(15) 5436(11) 1133(12) 3847(4) 65(2) Table A.23 Bond lengths [Å] and angles [°] for 2a (369PG_0mS). Cr(1)-C(14) 1.821(8) C(4)-Cr(1)-C(5) 37.1(3) C(3)-C(4)-C(5) 118.6(7) Cr(1)-C(13) 1.825(8) C(14)-Cr(1)-C(3) 116.9(3) C(3)-C(4)-Cr(1) 71.8(4) Cr(1)-C(15) 1.829(8) C(13)-Cr(1)-C(3) 91.5(3) C(5)-C(4)-Cr(1) 71.5(4) Cr(1)-C(4) 2.208(7) C(15)-Cr(1)-C(3) 155.3(3) C(3)-C(4)-H(4) 120.7 Cr(1)-C(5) 2.209(7) C(4)-Cr(1)-C(3) 36.7(3) C(5)-C(4)-H(4) 120.7 Cr(1)-C(3) 2.212(8) C(5)-Cr(1)-C(3) 65.9(3) Cr(1)-C(4)-H(4) 128.1 Cr(1)-C(2) 2.213(7) C(14)-Cr(1)-C(2) 92.7(3) C(6)-C(5)-C(4) 119.9(7) Cr(1)-C(6) 2.217(6) C(13)-Cr(1)-C(2) 119.1(3) C(6)-C(5)-Cr(1) 72.1(4) Cr(1)-C(1) 2.239(6) C(15)-Cr(1)-C(2) 151.8(3) C(4)-C(5)-Cr(1) 71.4(4) Si(1)-C(9) 1.852(7) C(4)-Cr(1)-C(2) 66.4(3) C(6)-C(5)-H(5) 120.1 Si(1)-C(7) 1.861(7) C(5)-Cr(1)-C(2) 78.2(3) C(4)-C(5)-H(5) 120.1 Si(1)-C(8) 1.871(7) C(3)-Cr(1)-C(2) 36.5(2) Cr(1)-C(5)-H(5) 128.7 Si(1)-C(1) 1.888(7) C(14)-Cr(1)-C(6) 122.1(3) C(5)-C(6)-C(1) 122.8(7) Ge(1)-C(11) 1.920(8) C(13)-Cr(1)-C(6) 150.2(3) C(5)-C(6)-Cr(1) 71.4(4) Ge(1)-C(7) 1.941(7) C(15)-Cr(1)-C(6) 90.2(3) C(1)-C(6)-Cr(1) 72.3(4) Ge(1)-C(10) 1.941(9) C(4)-Cr(1)-C(6) 66.2(3) C(5)-C(6)-H(6) 118.6 Ge(1)-C(12) 1.947(9) C(5)-Cr(1)-C(6) 36.5(2) C(1)-C(6)-H(6) 118.6 O(1)-C(13) 1.152(8) C(3)-Cr(1)-C(6) 77.2(3) Cr(1)-C(6)-H(6) 130.5 O(2)-C(14) 1.163(8) C(2)-Cr(1)-C(6) 65.8(3) Si(1)-C(7)-Ge(1) 119.9(4) O(3)-C(15) 1.151(8) C(14)-Cr(1)-C(1) 93.9(3) Si(1)-C(7)-H(7A) 107.3 C(1)-C(6) 1.413(9) C(13)-Cr(1)-C(1) 156.4(3) Ge(1)-C(7)-H(7A) 107.3 C(1)-C(2) 1.425(9) C(15)-Cr(1)-C(1) 114.5(3) Si(1)-C(7)-H(7B) 107.3 C(2)-C(3) 1.384(9) C(4)-Cr(1)-C(1) 79.8(3) Ge(1)-C(7)-H(7B) 107.3 C(2)-H(2) 0.93 C(5)-Cr(1)-C(1) 67.1(3) H(7A)-C(7)-H(7B) 106.9 C(3)-C(4) 1.391(10) C(3)-Cr(1)-C(1) 66.8(3) Si(1)-C(8)-H(8A) 109.5 C(3)-H(3) 0.93 C(2)-Cr(1)-C(1) 37.3(2) Si(1)-C(8)-H(8B) 109.5 C(4)-C(5) 1.405(11) C(6)-Cr(1)-C(1) 37.0(2) H(8A)-C(8)-H(8B) 109.5 C(4)-H(4) 0.93 C(9)-Si(1)-C(7) 113.0(4) Si(1)-C(8)-H(8C) 109.5 C(5)-C(6) 1.386(9) C(9)-Si(1)-C(8) 109.7(4) H(8A)-C(8)-H(8C) 109.5 C(5)-H(5) 0.93 C(7)-Si(1)-C(8) 110.4(4) H(8B)-C(8)-H(8C) 109.5 C(6)-H(6) 0.93 C(9)-Si(1)-C(1) 108.0(3) Si(1)-C(9)-H(9A) 109.5 C(7)-H(7A) 0.97 C(7)-Si(1)-C(1) 109.0(3) Si(1)-C(9)-H(9B) 109.5 C(7)-H(7B) 0.97 C(8)-Si(1)-C(1) 106.5(3) H(9A)-C(9)-H(9B) 109.5 C(8)-H(8A) 0.96 C(11)-Ge(1)-C(7) 108.9(4) Si(1)-C(9)-H(9C) 109.5 C(8)-H(8B) 0.96 C(11)-Ge(1)-C(10) 109.1(4) H(9A)-C(9)-H(9C) 109.5 C(8)-H(8C) 0.96 C(7)-Ge(1)-C(10) 112.4(4) H(9B)-C(9)-H(9C) 109.5 C(9)-H(9A) 0.96 C(11)-Ge(1)-C(12) 107.9(5) Ge(1)-C(10)-H(10A) 109.5 C(9)-H(9B) 0.96 C(7)-Ge(1)-C(12) 108.3(4) Ge(1)-C(10)-H(10B) 109.5 155 C(9)-H(9C) 0.96 C(10)-Ge(1)-C(12) 110.0(5) H(10A)-C(10)-H(10B) 109.5 C(10)-H(10A) 0.96 C(6)-C(1)-C(2) 115.8(6) Ge(1)-C(10)-H(10C) 109.5 C(10)-H(10B) 0.96 C(6)-C(1)-Si(1) 121.4(5) H(10A)-C(10)-H(10C) 109.5 C(10)-H(10C) 0.96 C(2)-C(1)-Si(1) 122.8(5) H(10B)-C(10)-H(10C) 109.5 C(11)-H(11A) 0.96 C(6)-C(1)-Cr(1) 70.7(4) Ge(1)-C(11)-H(11A) 109.5 C(11)-H(11B) 0.96 C(2)-C(1)-Cr(1) 70.3(4) Ge(1)-C(11)-H(11B) 109.5 C(11)-H(11C) 0.96 Si(1)-C(1)-Cr(1) 130.2(3) H(11A)-C(11)-H(11B) 109.5 C(12)-H(12A) 0.96 C(3)-C(2)-C(1) 121.4(7) Ge(1)-C(11)-H(11C) 109.5 C(12)-H(12B) 0.96 C(3)-C(2)-Cr(1) 71.8(4) H(11A)-C(11)-H(11C) 109.5 C(12)-H(12C) 0.96 C(1)-C(2)-Cr(1) 72.3(4) H(11B)-C(11)-H(11C) 109.5 C(14)-Cr(1)-C(13) 87.7(3) C(3)-C(2)-H(2) 119.3 Ge(1)-C(12)-H(12A) 109.5 C(14)-Cr(1)-C(15) 87.8(3) C(1)-C(2)-H(2) 119.3 Ge(1)-C(12)-H(12B) 109.5 C(13)-Cr(1)-C(15) 89.1(3) Cr(1)-C(2)-H(2) 129 H(12A)-C(12)-H(12B) 109.5 C(14)-Cr(1)-C(4) 153.1(3) C(2)-C(3)-C(4) 121.4(7) Ge(1)-C(12)-H(12C) 109.5 C(13)-Cr(1)-C(4) 88.2(3) C(2)-C(3)-Cr(1) 71.8(4) H(12A)-C(12)-H(12C) 109.5 C(15)-Cr(1)-C(4) 118.7(3) C(4)-C(3)-Cr(1) 71.5(5) H(12B)-C(12)-H(12C) 109.5 C(14)-Cr(1)-C(5) 158.6(3) C(2)-C(3)-H(3) 119.3 O(1)-C(13)-Cr(1) 179.2(8) C(13)-Cr(1)-C(5) 113.7(3) C(4)-C(3)-H(3) 119.3 O(2)-C(14)-Cr(1) 176.6(6) C(15)-Cr(1)-C(5) 91.3(3) Cr(1)-C(3)-H(3) 130.1 O(3)-C(15)-Cr(1) 178.9(8) Table A.24 Anisotropic displacement parameters (Å2x 103) for 2a (369PG_0mS). The anisotropic displacement factor exponent takes the form: -22[ h2 a*2U11 + ... + 2 h k a* b* U12]. U11 U22 U33 U23 U13 U12 Cr(1) 42(1) 50(1) 51(1) -11(1) 2(1) -15(1) Si(1) 51(1) 52(1) 56(1) -1(1) -6(1) -27(1) Ge(1) 102(1) 79(1) 54(1) -8(1) 0(1) -48(1) O(1) 87(4) 92(5) 96(5) 7(4) -32(4) -9(4) O(2) 77(4) 129(5) 89(4) -48(4) 40(3) -42(4) O(3) 83(4) 93(5) 192(8) -56(5) 17(4) -54(4) C(1) 36(3) 54(4) 62(4) -9(3) 3(3) -21(3) C(2) 55(4) 54(4) 62(5) -11(4) 6(4) -27(4) C(3) 73(5) 64(5) 67(5) -4(4) 10(4) -33(4) C(4) 53(5) 96(7) 52(5) -8(5) 11(4) -26(4) C(5) 45(4) 74(5) 63(5) -24(4) 6(4) -16(4) C(6) 35(4) 53(4) 70(5) -10(4) 7(3) -10(3) C(7) 92(6) 54(4) 60(5) -6(4) -11(4) -33(4) C(8) 51(5) 99(7) 91(6) 0(5) -21(4) -26(4) C(9) 65(5) 70(5) 92(6) -4(4) 2(4) -43(4) C(10) 154(10) 111(8) 78(7) 17(6) -23(7) -44(7) C(11) 201(12) 102(8) 77(7) -30(6) 4(7) -79(8) C(12) 120(8) 171(11) 100(8) -45(7) 31(7) -91(8) C(13) 60(5) 65(5) 65(5) -17(4) 2(4) -9(4) C(14) 47(4) 66(5) 58(5) -9(4) -2(4) -21(4) C(15) 44(4) 55(5) 95(6) -21(4) 6(4) -17(4) 156 Table A.25 Hydrogen coordinates (x 104) and isotropic displacement parameters (Å2x 10 3) for 2a (369PG_0mS). x y z U(eq) H(2) 2318 -2857 3162 67 H(3) 2672 -3990 4185 82 H(4) 2199 -1588 4866 84 H(5) 1132 2099 4500 75 H(6) 633 3276 3479 68 H(7A) 1577 -1737 1943 81 H(7B) 3819 -1966 2142 81 H(8A) -2132 3445 1773 125 H(8B) -2576 3751 2456 125 H(8C) -2399 1631 2231 125 H(9A) 3746 2718 2255 108 H(9B) 1553 4518 2445 108 H(9C) 1899 4077 1771 108 H(10A) -416 2259 784 183 H(10B) 1048 1923 214 183 H(10C) 1197 3322 688 183 H(11A) 4725 -4284 926 180 H(11B) 4035 -2813 297 180 H(11C) 2289 -3149 717 180 H(12A) 5660 1196 1070 177 H(12B) 6650 -730 685 177 H(12C) 6835 -1205 1393 177 Table A.26 Torsion angles [°] for 2a (369PG_0mS). C(9)-Si(1)-C(1)-C(6) 40.6(6) Cr(1)-C(2)-C(3)-C(4) 53.6(7) Cr(1)-C(5)-C(6)-C(1) 53.4(6) C(7)-Si(1)-C(1)-C(6) 163.8(5) C(1)-C(2)-C(3)-Cr(1) -54.9(6) C(4)-C(5)-C(6)-Cr(1) -55.1(6) C(8)-Si(1)-C(1)-C(6) -77.1(6) C(14)-Cr(1)-C(3)-C(2) -53.4(5) C(2)-C(1)-C(6)-C(5) 2.6(9) C(9)-Si(1)-C(1)-C(2) -141.0(5) C(13)-Cr(1)-C(3)-C(2) -141.5(5) Si(1)-C(1)-C(6)-C(5) -179.0(5) C(7)-Si(1)-C(1)-C(2) -17.8(6) C(15)-Cr(1)-C(3)-C(2) 127.3(8) Cr(1)-C(1)-C(6)-C(5) -53.0(6) C(8)-Si(1)-C(1)-C(2) 101.3(6) C(4)-Cr(1)-C(3)-C(2) 133.5(7) C(2)-C(1)-C(6)-Cr(1) 55.5(5) C(9)-Si(1)-C(1)-Cr(1) -49.8(5) C(5)-Cr(1)-C(3)-C(2) 103.1(5) Si(1)-C(1)-C(6)-Cr(1) -126.0(4) C(7)-Si(1)-C(1)-Cr(1) 73.3(5) C(6)-Cr(1)-C(3)-C(2) 66.4(4) C(14)-Cr(1)-C(6)-C(5) -179.5(5) C(8)-Si(1)-C(1)-Cr(1) -167.5(4) C(1)-Cr(1)-C(3)-C(2) 28.9(4) C(13)-Cr(1)-C(6)-C(5) -3.4(9) C(14)-Cr(1)-C(1)-C(6) -142.6(4) C(14)-Cr(1)-C(3)-C(4) 173.1(5) C(15)-Cr(1)-C(6)-C(5) -91.9(5) C(13)-Cr(1)-C(1)-C(6) 124.2(7) C(13)-Cr(1)-C(3)-C(4) 84.9(5) C(4)-Cr(1)-C(6)-C(5) 29.6(5) C(15)-Cr(1)-C(1)-C(6) -53.3(5) C(15)-Cr(1)-C(3)-C(4) -6.2(10) C(3)-Cr(1)-C(6)-C(5) 66.6(5) C(4)-Cr(1)-C(1)-C(6) 63.8(4) C(5)-Cr(1)-C(3)-C(4) -30.4(5) C(2)-Cr(1)-C(6)-C(5) 103.3(5) C(5)-Cr(1)-C(1)-C(6) 27.2(4) C(2)-Cr(1)-C(3)-C(4) -133.5(7) C(1)-Cr(1)-C(6)-C(5) 134.9(7) C(3)-Cr(1)-C(1)-C(6) 99.7(5) C(6)-Cr(1)-C(3)-C(4) -67.2(5) C(14)-Cr(1)-C(6)-C(1) 45.6(5) C(2)-Cr(1)-C(1)-C(6) 128.0(6) C(1)-Cr(1)-C(3)-C(4) -104.6(5) C(13)-Cr(1)-C(6)-C(1) -138.3(7) C(14)-Cr(1)-C(1)-C(2) 89.3(4) C(2)-C(3)-C(4)-C(5) 2.2(11) C(15)-Cr(1)-C(6)-C(1) 133.2(5) C(13)-Cr(1)-C(1)-C(2) -3.8(9) Cr(1)-C(3)-C(4)-C(5) 55.9(6) C(4)-Cr(1)-C(6)-C(1) -105.3(5) C(15)-Cr(1)-C(1)-C(2) 178.7(4) C(2)-C(3)-C(4)-Cr(1) -53.8(7) C(5)-Cr(1)-C(6)-C(1) -134.9(7) C(4)-Cr(1)-C(1)-C(2) -64.3(4) C(14)-Cr(1)-C(4)-C(3) -13.7(9) C(3)-Cr(1)-C(6)-C(1) -68.3(4) C(5)-Cr(1)-C(1)-C(2) -100.8(5) C(13)-Cr(1)-C(4)-C(3) -95.0(5) C(2)-Cr(1)-C(6)-C(1) -31.6(4) C(3)-Cr(1)-C(1)-C(2) -28.3(4) C(15)-Cr(1)-C(4)-C(3) 177.0(5) C(9)-Si(1)-C(7)-Ge(1) -41.4(6) C(6)-Cr(1)-C(1)-C(2) -128.0(6) C(5)-Cr(1)-C(4)-C(3) 129.9(7) C(8)-Si(1)-C(7)-Ge(1) 81.8(5) C(14)-Cr(1)-C(1)-Si(1) -27.4(5) C(2)-Cr(1)-C(4)-C(3) 28.0(4) C(1)-Si(1)-C(7)-Ge(1) -161.6(4) 157 C(13)-Cr(1)-C(1)-Si(1) -120.6(7) C(6)-Cr(1)-C(4)-C(3) 100.8(5) C(11)-Ge(1)-C(7)-Si(1) -159.7(5) C(15)-Cr(1)-C(1)-Si(1) 61.9(5) C(1)-Cr(1)-C(4)-C(3) 64.6(5) C(10)-Ge(1)-C(7)-Si(1) -38.6(6) C(4)-Cr(1)-C(1)-Si(1) 179.0(5) C(14)-Cr(1)-C(4)-C(5) -143.6(6) C(12)-Ge(1)-C(7)-Si(1) 83.2(6) C(5)-Cr(1)-C(1)-Si(1) 142.4(6) C(13)-Cr(1)-C(4)-C(5) 135.1(5) C(14)-Cr(1)-C(13)-O(1) 45(60) C(3)-Cr(1)-C(1)-Si(1) -145.1(5) C(15)-Cr(1)-C(4)-C(5) 47.1(6) C(15)-Cr(1)-C(13)-O(1) -43(60) C(2)-Cr(1)-C(1)-Si(1) -116.8(6) C(3)-Cr(1)-C(4)-C(5) -129.9(7) C(4)-Cr(1)-C(13)-O(1) -162(100) C(6)-Cr(1)-C(1)-Si(1) 115.2(6) C(2)-Cr(1)-C(4)-C(5) -101.9(5) C(5)-Cr(1)-C(13)-O(1) -134(60) C(6)-C(1)-C(2)-C(3) -1.1(9) C(6)-Cr(1)-C(4)-C(5) -29.2(4) C(3)-Cr(1)-C(13)-O(1) 161(100) Si(1)-C(1)-C(2)-C(3) -179.5(5) C(1)-Cr(1)-C(4)-C(5) -65.3(5) C(2)-Cr(1)-C(13)-O(1) 136(60) Cr(1)-C(1)-C(2)-C(3) 54.6(6) C(3)-C(4)-C(5)-C(6) -0.7(11) C(6)-Cr(1)-C(13)-O(1) -132(60) C(6)-C(1)-C(2)-Cr(1) -55.7(5) Cr(1)-C(4)-C(5)-C(6) 55.4(6) C(1)-Cr(1)-C(13)-O(1) 139(60) Si(1)-C(1)-C(2)-Cr(1) 125.9(4) C(3)-C(4)-C(5)-Cr(1) -56.1(6) C(13)-Cr(1)-C(14)-O(2) -43(12) C(14)-Cr(1)-C(2)-C(3) 134.2(5) C(14)-Cr(1)-C(5)-C(6) 1.2(11) C(15)-Cr(1)-C(14)-O(2) 46(12) C(13)-Cr(1)-C(2)-C(3) 45.4(5) C(13)-Cr(1)-C(5)-C(6) 178.2(5) C(4)-Cr(1)-C(14)-O(2) -125(12) C(15)-Cr(1)-C(2)-C(3) -135.3(7) C(15)-Cr(1)-C(5)-C(6) 88.6(5) C(5)-Cr(1)-C(14)-O(2) 134(12) C(4)-Cr(1)-C(2)-C(3) -28.2(4) C(4)-Cr(1)-C(5)-C(6) -131.4(7) C(3)-Cr(1)-C(14)-O(2) -134(12) C(5)-Cr(1)-C(2)-C(3) -65.3(5) C(3)-Cr(1)-C(5)-C(6) -101.3(5) C(2)-Cr(1)-C(14)-O(2) -162(12) C(6)-Cr(1)-C(2)-C(3) -101.6(5) C(2)-Cr(1)-C(5)-C(6) -65.0(5) C(6)-Cr(1)-C(14)-O(2) 135(12) C(1)-Cr(1)-C(2)-C(3) -132.9(6) C(1)-Cr(1)-C(5)-C(6) -27.6(4) C(1)-Cr(1)-C(14)-O(2) 160(12) C(14)-Cr(1)-C(2)-C(1) -92.9(4) C(14)-Cr(1)-C(5)-C(4) 132.6(8) C(14)-Cr(1)-C(15)-O(3) -75(43) C(13)-Cr(1)-C(2)-C(1) 178.3(4) C(13)-Cr(1)-C(5)-C(4) -50.4(6) C(13)-Cr(1)-C(15)-O(3) 13(43) C(15)-Cr(1)-C(2)-C(1) -2.5(8) C(15)-Cr(1)-C(5)-C(4) -140.0(5) C(4)-Cr(1)-C(15)-O(3) 100(43) C(4)-Cr(1)-C(2)-C(1) 104.7(5) C(3)-Cr(1)-C(5)-C(4) 30.1(5) C(5)-Cr(1)-C(15)-O(3) 126(43) C(5)-Cr(1)-C(2)-C(1) 67.6(4) C(2)-Cr(1)-C(5)-C(4) 66.4(5) C(3)-Cr(1)-C(15)-O(3) 104(43) C(3)-Cr(1)-C(2)-C(1) 132.9(6) C(6)-Cr(1)-C(5)-C(4) 131.4(7) C(2)-Cr(1)-C(15)-O(3) -167(100) C(6)-Cr(1)-C(2)-C(1) 31.3(4) C(1)-Cr(1)-C(5)-C(4) 103.8(5) C(6)-Cr(1)-C(15)-O(3) 163(100) C(1)-C(2)-C(3)-C(4) -1.2(11) C(4)-C(5)-C(6)-C(1) -1.7(10) C(1)-Cr(1)-C(15)-O(3) -168(100) 158 VITA Paulina Elena Gonzalez Navarro was born in Irapuato, Guanajuato, Mexico. In 2005, she started her Bachelor degree at Universidad de Guanajuato in Guanajuato, Mexico. Paulina performed undergraduate research with Professor Dr. Eduardo Peña Cabrera, where she worked in the synthesis, characterization and functionalization of fluorophores based in the boron dipyrromethene (BODIPY). During the Summer of 2008, she traveled to the University of Texas at El Paso where she met Professor Dr. Keith H. Pannell, where she performed research under his guidance. Paulina’s undergraduate thesis “Incorporación del ligando acetilacetonato a derivados del borodipirrometene (BDP)” was supervised by Dr. Peña Cabrera. She earned Bachelor degree in Chemistry from Universidad de Guanajuato in 2010. During the Fall of the same year, Paulina moved to El Paso, Texas to begin her graduate degree in Chemistry at the University of Texas at El Paso, where she worked in Dr. Keith H. Pannell’s research group. Her work has been published in peer-reviewed journals. In December of 2016, Paulina received a Doctor of Philosophy in Chemistry, and her dissertation entitled “New Organosilicon Chemistry” was supervised by Dr. Pannell. She wants to pursue a career in industry. Permanent address: Obregón #60. Ex-Hacienda de San José de Pantoja. Valle de Santiago, Guanajuato, México. C.P. 38440. Contact Information: [email protected] This dissertation was typed by the author. 159