TRIS(1,3-DIHYDROXY-2-PROPYL)AMINE, A PLANAR TRIALKYLAMINE: SYNTHESIS, STRUCTURE, AND PROPERTIES. A POTENTIAL PRECURSOR TO HYPERVALENT NITROGEN Except where reference is made to the work of others, the work described in this dissertation is my own or was done in collaboration with my advisory committee. This dissertation does not include proprietary or classified information __________________________ Yuanping Jie Certificate of Approval: ______________________________ ______________________________ Edward J. Parish Peter D. Livant, Chair Professor Associate Professor Chemistry and Biochemistry Chemistry and Biochemistry ______________________________ ______________________________ Susanne Striegler Thomas E. Albrecht-Schmitt Assistant Professor Associate Professor Chemistry and Biochemistry Chemistry and Biochemistry ____________________ Stephen L. McFarland Acting Dean Graduate School TRIS(1,3-DIHYDROXY-2-PROPYL)AMINE, A PLANAR TRIALKYLAMINE: SYNTHESIS, STRUCTURE, AND PROPERTIES. A POTENTIAL PRECURSOR TO HYPERVALENT NITROGEN Yuanping Jie A Dissertation Submitted to The Graduate Faculty of Auburn University In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Auburn, Alabama May 11, 2006 TRIS(1,3-DIHYDROXY-2-PROPYL)AMINE, A PLANAR TRIALKYLAMINE: SYNTHESIS, STRUCTURE, AND PROPERTIES. A POTENTIAL PRECURSOR TO HYPERVALENT NITROGEN Yuanping Jie Permission is granted to Auburn University to make copies of this dissertation at its discretion, upon request of individuals or institutions and at their expense. The author reserves all publication rights. _______________________________ Signature of Author _______________________________ Date of Graduation iii VITA Yuanping Jie, daughter of Chuanlin Jie and Xiulan Bao, was born on March 26, 1966, in Luan, Anhui province, the People’s Republic of China. She graduated with a Bachelor of Science degree in Chemistry in 1988 from Anhui Normal University. She received her M.S. degree in Organic Chemistry in 1991 from East China Normal University. From 1991 to 2001, she worked for Shanghai Chemical Reagent Research Institute. In 1991, she married Jie Liang, son of Huading Liang and Bangzhi Zhao. They have one daughter, Zhongling Liang. She entered the Graduate School at Auburn University, Auburn, Alabama in January, 2003. iv DISSERTATION ABSTRACT TRIS(1,3-DIHYDROXY-2-PROPYL)AMINE, A PLANAR TRIALKYLAMINE: SYNTHESIS, STRUCTURE, AND PROPERTIES. A POTENTIAL PRECURSOR TO HYPERVALENT NITROGEN Yuanping Jie Doctor of Philosophy, May 11, 2006 (M.S., East China Normal University, 1991) (B.S., Anhui Normal University, 1988) 184 Typed Pages Directed by Peter D. Livant The hindered amine tris(1,3-dihydroxy-2-propyl)amine, 36, is a potential precursor to possible examples of nitrogen hypervalency. There are no simple, effective, and general methods to synthesize hindered tertiary amines. Extending previous work in our laboratory on Rh2(OAc)4-catalyzed insertions of carbenoids into N-H bonds, we achieved a synthesis of 36 in five steps and 49% overall yield. Starting from commercially available dihydroxyacetone dimer, our synthesis makes 36 available in multigram quantities. v Some properties and structure of 36 have been studied. The pKa of 36 was found to be 3.08 ± 0.03, a low value for a tertiary amine. The X-ray crystal structure of 36 showed the nitrogen is essentially planar (sum of C-N-C angles 359.05(7) °), and the average C-N bond length (1.454 Å) was shorter than normal. An explanation of this bond contraction ox is offered. The oxidation potential E1/2 of 36 measured by cyclic voltammetry was found to be 0.88 V. The oxidation was reversible; oxidations of ordinary tertiary amines are usually irreversible. The X-ray crystal structure of 36·HCl revealed a severely flattened tetrahedral geometry about nitrogen (average H-N-C angle 102.3 °). The reaction of 36 with boric acid led to a “one- boron” compound, 67 (2,8,9- tris(hydroxymethyl)-5-bora-1-aza-4,6,11-trioxytricyclo[3.3.3.01,5]undecane) and a “two-boron” compound, 69 (1,7-dibora-11-aza-2,6,8,14,15,17-hexaoxytetracyclo- [8.4.2.2.7,1204,11]octadecane). The X-ray crystal structure of 67 showed a dative bond between nitrogen and boron (1.6875(13) Å). Compound 69 is very hydrolytically unstable, but the X-ray crystal structure of a complex of 69 with pyridine confirmed the presence in 69 of two borons. The reaction of 36 with Z-Si(OEt)3 (Z = Me, Ph) led to analogous "one-silicon" and "two-silicon" compounds. The X-ray crystal structures of both two-silicon compounds revealed a nearly symmetrical SiNSi array (Z = Me) and an unsymmetrical one (Z = Ph). vi ACKNOWLEDGMENTS I would like to express my heartfelt appreciation to my advisor Dr. Peter Livant. Not only has he given me invaluable academic guidance but also he has given my family much assistance. I thank all of my committee members for their time spent on this dissertation. I thank the faculty in the Chemistry and Biochemistry Department for their teaching. I thank my group members and my friends for their cooperation and help. Last but not least, I would like to thank my parents, my husband and my daughter for their support during this work. vii Style manual or Journal used: Journal of Organic Chemistry Computer software used: Microsoft Word 2000 and ChemDraw viii CONTENTS LIST OF TABLES............................................................................................................. xi LIST OF SCHEMES......................................................................................................... xii LIST OF FIGURES ......................................................................................................... xiii I. INTRODUCTION......................................................................................................1 1.1. Hypervalent bond……………………………………………………………….1 1.1.1.Three-center four-electron (hypervalent) bond……………………………3 1.1.2. Extended hypervalent bond (5c-6e bond)………………………………...8 1.2. Hypervalent compounds based on second row elements……………………...10 1.3. Hypervalent nitrogen………………………………………………………….15 1.3.1. Potential difficulties in forming hypervalent nitrogen…………………..15 1.3.2. Some attempts to synthesize hypervalent nitrogen species……………..16 1.3.3. Ideas for the synthesis of precursors to hypervalent 10-N-5 species……18 1.3.4. New target precursor for 10-N-5 species………………………………..22 I I. RESULTS AND DISCUSSION ..............................................................................26 2.1. The synthesis of tertiary amine 36…………………………………………….26 2.1.1. Previous work in our lab………………………………………………...26 2.1.2. The synthesis of compound 36 starting with dihydroxyacetone………...28 2.1.3. Some properties of tertiary amine 36……………………………………39 2.2. Tris(1,3-dihydroxy-2-propyl)amine 36 incorporating ix some main group elements……………………………………………………..49 2.2.1. Reactions of 36 with various sources of boron………………………….50 2.2.2. Reactions of 36 with various sources of silicon…………………………64 2.3. Synthesis of tertiary amine 86…………………………………………………76 I I I. CONCLUSIONS…………………………………………………………………...79 I V. EXPERIMENTAL....................................................................................................81 V. REFERENCES..........................................................................................................96 V I. APPENICES ..........................................................................................................107 Appendix 1………………………………………………………………………..108 Appendix 2.……………………………………………………………………….117 Appendix 3..………………………………………………………………………126 Appendix 4..………………………………………………………………………140 Appendix 5.……………………………………………………………………….149 Appendix 6..………………………………………………………………………162 x LIST OF TABLES 1. Some reactions of hindered secondary amines with diazo compounds catalyzed by Rh2(OAc)4 ...........................................................................29 2. h for various trialkylamines .........................................................................................41 3. Structure parameters of 36 and some unhindered trialkylamines from x-ray crystallography ..........................................................................................43 4. Geometries of protonated trialkylamines.....................................................................46 5. The “triple” hydrogen bonding interaction of some tertiary amine cations.................47 6. Geometric parameters of 67 and TEAB ......................................................................57 7. Geometric data of 71 from X-ray crystallography…………………………………...62 8. Some structural feature of silatranes, ZSi(OCH2CH2)3N……………………………68 9. Some interesting structural parameters of 74, 76 compared to 80, 81 from x-ray crystallography ...........................................................................72 xi LIST OF SCHEMES 1. Modes of creation of a 3c-4e bond in pentacoordinate hypervalent molecules.........................................................................4 2. Failure to prepare 36 by reductive amination ..............................................................28 3. Initial investigations into the synthesis of 36...............................................................30 4. Route from dihydroxyacetone to tertiary amine 36 .....................................................32 5. Possible pathways in the reaction of 36 with (MeO)3B...............................................50 6. The reaction of 36 with H3BO3 ....................................................................................60