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Carbon-Sulfur Bond Formation Via Alkene Addition to an Oxidized Ruthenium-Thiolate

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Carbon-Sulfur Bond Formation Via Alkene Addition to an Oxidized Ruthenium-Thiolate University of Louisville ThinkIR: The University of Louisville's Institutional Repository Electronic Theses and Dissertations 5-2007 Carbon-sulfur bond formation via alkene addition to an oxidized ruthenium-thiolate. Kiran B. Venna 1974- University of Louisville Follow this and additional works at: https://ir.library.louisville.edu/etd Recommended Citation Venna, Kiran B. 1974-, "Carbon-sulfur bond formation via alkene addition to an oxidized ruthenium- thiolate." (2007). Electronic Theses and Dissertations. Paper 1490. https://doi.org/10.18297/etd/1490 This Master's Thesis is brought to you for free and open access by ThinkIR: The University of Louisville's Institutional Repository. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of ThinkIR: The University of Louisville's Institutional Repository. This title appears here courtesy of the author, who has retained all other copyrights. For more information, please contact [email protected]. CARBON-SULFUR BOND FORMATION VIA ALKENE ADDITION TO AN OXIDIZED RUTHENIUM-THIOLATE By KIRAN VENNA A Thesis Submitted to the Faculty of the Graduate School of the University of Louisville in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE Department of Chemistry University of Louisville Louisville, Kentucky May 2007 CARBON-SULFUR BOND FORMATION VIA ALKENE ADDITION TO AN OXIDIZED RUTHENIUM-THIOLATE By Kiran Venna M.S. Nagarjuna University, 1998 May 2007 ____________________________________ Advisor: Dr. Craig A. Grapperhaus ____________________________________ Dr. Mark E. Noble ____________________________________ Dr. Frank P. Zamborini ____________________________________ Dr. William Dean ii DEDICATION This thesis is dedicated to my parents Anjali Devi and Madhusudhan Rao, to my brother and sister Vardhan Rao and Sunanda, and to my wife Sarika. iii ACKNOWLEDGMENTS I would like to thank my advisor Dr. Craig A. Grapperhaus for mentoring me over the past several years. I am very grateful for his guidance and patience. Being a part of his group has helped me develop as a chemist and analytical thinker. I am indebted to him for all the knowledge and experience I gained while working under his supervision. I would also like to thank several of the faculty at University of Louisville for their assistance over the past few years. I would like to express my sincere gratitude to my committee members Dr. Noble and Dr. Zamborini for their advice. In addition, I also would like to thank Dr. William Dean for his time in evaluating my thesis. Special thanks to Dr. Mark Mashuta for his X-ray expertise and Dr. Neal Stolowich for the help with NMR collection. I would also like to thank Dr. Mona Zady, who has helped me tremendously as my senior instructor for teaching labs. I would like to specially thank my lab mate Martin O’Toole for his support to me throughout my graduation years. My life as a graduate student would have been unbearable without my fellow group members and friends; Majda Kreso, Laura Haysley, Kagna Ouch and Ceasar Masitas. I am grateful for their support and their friendship.. Finally, I would like to thank my family. I thank my wonderful parents who made all of my dreams possible and stood behind my every decision. I thank my brother and sister, Vardhan and Sunanda, for believing in me and encouraging me. I would like to thank my wife Sarika, who has been great support to me in every possible way. iv ABSTRACT Carbon-sulfur bond formation via alkene addition to an oxidized ruthenium-thiolate Kiran Venna, M.S., Nagarjuna University Chair Advisory Committee: Dr. Craig A. Grapperhaus May, 2007 This thesis reports the reactivity of the trithiolato Ru complex PPN[Ru(DPPBT)3] (DPPBT = 2-diphenylphosphinobenzenethiolate) (1a) with alkenes upon oxidation. Complex 1a in acetonitrile shows two redox events at -345 mV and +455 mV in the square wave voltammogram. Bulk oxidation at a holding potential of +100 mV yields [tris(2-(diphenylphosphino)thiaphenolato)ruthenium(III)], (1b). During oxidation, the absorption bands at 540 nm, 797 nm and 1041 nm grow in intensity while there is a decrease in the absorption band at 435 nm. A plot of charge versus time during bulk electrolysis shows a total coulometric charge of 1.14 electron equivalent. The square wave voltammogram is not effected by this oxidation. Further oxidation by one electron in the presence of ethylene at a holding potential of +620 mV yields [(ethane-1,2- diylbis(thio-2,1-phenylene)diphenylphosphine)ruthenium(II)] hexafluorophosphate, (2a). During oxidation the absorption bands at 540 nm, 797 nm and 1041 nm decrease in intensity. Complex 2a displays a single redox couple at +804 mV. The +ESI-MS of 2a shows a parent ion peak at m/z = 1009.1013 amu. The 31P NMR spectrum of 2a shows v chemical shift values of δ1 = 61.0 ppm, δ2 = 40.3 ppm, δ3 = 37.5 ppm with coupling constants of J12 ≈ J13 ≈ 30 Hz and J23 = 304 Hz. Complex 2a can be oxidized at a holding potential of +1000 mV to yield [(ethane-1,2-diylbis(thio-2,1-phenylene)diphenyl phosphine)ruthenium(III)] hexaflurophosphate, (2b). The EPR of 2b displays a rhombic signal with g1 = 2.09, g2 = 2.03, g3 = 2.04. Oxidation of 1b in the presence of alkenes including 1-hexene, styrene, cyclohexene, and norbornene yield products similar to 2a. Each of these products can be oxidized to an analogue of 2b. Complex 2a can also be prepared, as the bromide salt, from 1a and 1,2-dibromoethane. The complex [(ethane-1,2- diylbis(thio-2,1-phenylene)diphenylphosphine)ruthenium(II)] bromide crystals as thin yellow plates in the monoclinic space group P21/c with unit cell dimensions of a = 10.2565(9) Å, b = 13.2338(12) Å, c = 38.325(3) Å, and β = 93.3960(10)°. vi TABLE OF CONTENTS PAGE ACKNOWLEDGMENTS .........................................................................................iv ABSTRACT...............................................................................................................v LIST OF FIGURES ...................................................................................................ix LIST OF TABLES.....................................................................................................xii CHAPTER I. INTRODUCTION.........................................................................................1 II. EXPERIMENTAL METHODS.....................................................................7 Materials and Physical Methods ........................................................7 Electrochemical Syntheses.................................................................9 Chemical Synthesis............................................................................12 III. RESULTS AND DISCUSSION....................................................................14 IV. CONCLUSIONS............................................................................................44 REFERENCES ..........................................................................................................50 LIST OF APPENDICES ...........................................................................................53 APPENDIX A : Tables and Figure for Crystallographic Data...................................54 APPENDIX B: Electrochemistry...............................................................................61 APPENDIX C: UV-visible Spectroscopy..................................................................67 APPENDIX D: EPR Spectroscopy............................................................................71 APPENDIX E: NMR Spectroscopy...........................................................................74 APPENDIX F: Mass Spectroscopy ...........................................................................78 vii CURRICULUM VITAE............................................................................................82 viii LIST OF FIGURES FIGURE PAGE III-1 Square wave voltammogram of 1a in acetonitrile .............................21 III-2 Plot of charge versus time acquired during oxidation of 1a to 1b.....22 III-3 Electronic spectra obtained during oxidation of 1a to 1b..................23 III-4 Plot of charge versus time acquired during oxidation of 1b to 2a.....24 III-5 Electronic spectra obtained during oxidation of 1b to 2a..................25 III-6 Square wave voltammogram of 2a in acetonitrile .............................26 III-7 Comparison of square wave voltammogram of 1b and 2a................27 III-8 Plot of charge versus time acquired during oxidation of 2a to 2b.....29 III-9 Electronic spectra obtained during oxidation of 2a to 2b..................30 III-10 +ESI-MS of 2a in acetonitrile............................................................31 III-11 31P NMR spectrum of 2a in deuterated acetonitrile...........................32 III-12 EPR spectrum of 2b...........................................................................34 III-13 An ORTEP diagram of the cation of 2a with partial atom labeling scheme................................................................................................42 A-3 An ORTEP diagram of the cation of 2a with full atom labeling scheme................................................................................................60 B-1 Square wave voltammogram of 3a ....................................................62 B-2 Square wave voltammogram of 4a ....................................................62 B-3 Square wave voltammogram of 5a ....................................................63 ix B-4
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