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Hydrocarbyl and Hydride Complexes. (Under the Direction of Professor T Abstract LEE, JOHN P. Synthesis, Characterization and Reactivity of Ru(II) and Rh(I) Hydrocarbyl and Hydride Complexes. (Under the direction of Professor T. Brent Gunnoe.) The hydroarylation of multiple bonds is the addition of an aromatic C-H bond across a C=X (X = C, N or O) bond to produce new C-C bonds. Our group has been studying Ru(II) complexes of the type TpRu(L)(NCMe)R {Tp = hydridotris(pyrazolyl)borate; L = CO, PMe3, P(N-pyrrolyl)3 and P(OCH2)CEt; R = Me or Ph} for the catalytic hydroarylation of non-functionalized olefins. Insertion of the C=X (X = heteroatom) bond into a metal-aryl bond is a key step in catalytic hydroarylation reactions. Herein, insertion reactions of substrates that possess C-X multiple bonds into the Ru-Ph (Ph = phenyl) bond of TpRu(L)(NCMe)Ph (L = CO or PMe3) complexes have been explored. The results of these efforts have increased understanding of factors that control the insertion process. For example, the reaction of TpRu(CO)(NCMe)Ph with either N,N΄-di-n-hexylcarbodiimide or N,N΄-di-phenylcarbodiimide produces the amidinate complexes TpRu(CO){N,N-(R)NC(Ph)N(R)}(R = n-hexyl or phenyl). Heating TpRu(CO)(NCMe)Ph in the presence of t-butylisonitrile followed by addition of trimethylphosphine results in an equilibrium between TpRu(CO)(CNtBu)Ph and t TpRu(CO){C(Ph)=N( Bu)}(PMe3). Heating TpRu(CO)(NCMe)Ph in the presence of aldehydes results in the decarbonylation of the organic to produce TpRu(CO)2Ar (Ar = phenyl or p-tolyl) and benzene. DFT calculations were carried out to further delineate the thermodynamics and kinetics for C-X multiple bond insertion reactions involving complexes of the type TpRu(L)(NCMe)Ph. In addition, we have studied the possibility of the inter- and intramolecular hydroarylation of isonitriles catalyzed by TpRu(L)(NCMe)Ph complexes. In addition, efforts have been directed to Ru(II) complexes supported by sterically demanding N-heterocyclic carbene (NHC) ligands. For example, the novel 4-coordinate Ru(II) hydride complex [(IMes)2Ru(H)(CO)][BAr'4] {IMes = 1,3-bis-(2,4,6- trimethylphenyl)imidazol-2-ylidene; Ar' = 3,5-(CF3)-C6H3} has been prepared and studied. Both experimental and theoretical studies are consistent with a monomeric, diamagnetic 4- coordinate Ru(II) complex that possesses sawhorse geometry without agostic interactions. Attempts to grow X-ray quality crystals under a variety of conditions resulted in the formation of [(IMes)2Ru(H)(CO)(N2)][BAr'4] as determined by X-ray crystallography and confirmed by variable temperature NMR studies. Furthermore, the reaction of [(IMes)2Ru(H)(CO)][BAr'4] with t-butylisonitrile produces t [(IMes)2Ru(H)(CO)(CN Bu)2][BAr'4], which has been isolated and fully characterized including X-ray crystallography. [(IMes)2Ru(H)(CO)][BAr'4] reacts with D2 rapidly to produce [(IMes)2Ru(D)(CO)][BAr'4], and catalyzes the hydrogenation of olefins, aldehydes and ketones. Attempts to use [(IMes)2Ru(H)(CO)][BAr'4] for the catalytic addition of a benzene C-H across ethylene resulted in 1.5 turnovers of styrene. Studies of catalytic hydroarylation of olefins have been extended to d8 square planar catalyst precursors. In particular Rh(I) complexes of the type (tbubpy)Rh(L)R (tbubpy = 4,4'- di-tert-butyl-2,2'-bipyridyl; L = neutral 2-electron donor; R = Me or Ph) have been prepared as candidates for olefin hydroarylation and/or oxidative olefin hydroarylation. Initial results for the preparation of (tbubpy)Rh(NCMe)R are discussed. Synthesis, Characterization and Reactivity of Ru(II) and Rh(I) Hydrocarbyl and Hydride Complexes by John P. Lee A dissertation submitted to the Graduate Faculty of North Carolina State University In partial fulfillment of the requirements for the degree of Doctor of Philosophy Chemistry Raleigh, NC 2008 APPROVED BY: _________________________ _________________________ T. Brent Gunnoe Elon Ison Chair of Advisory Committee _________________________ _________________________ Paul A. Maggard Christian Melander Dedication I would like to dedicate this to my family. They helped to keep my spirits up from 450 miles away. ii Biography John P. Lee was born May 19, 1980 to Mary Elizabeth Sims and Paul W. Lee, Jr. He grew up in Chattanooga, Tennessee and graduated from Ooltewah High School in 1998. After high school he worked full-time while going to Chattanooga State Technical Community College part-time. After two years of working he decided to switch priorities and study chemistry full-time and work part-time. He received an A. S. degree in General Science from Chattanooga State in 2001. From there he moved down the street to the University of Tennessee at Chattanooga. While there he worked with Professor Gregory J. Grant, and graduated with a B. S. degree in chemistry in 2003. Next, he moved East across the Smokey Mountains to Raleigh, North Carolina to work with Professor T. Brent Gunnoe in synthetic/mechanistic organometallic chemistry. iii Acknowledgements I have no idea what I would do without my family. The biggest thing you ever said to me is no matter what you do or what choice you make for your future we will support you. That means a lot since not only did I think about taking you up a couple times on that offer while here but you never know where I will wind up in ten years. I also have to say thank you for putting up with my schedule since I didn’t come home near enough, and when there not only did I not stay long but I probably worked too much as well (!). In addition to family, my friends back home as well as those that I met here were always there to help me out. Several professors have impacted me over the years at NC State. My advisor Dr. T. Brent Gunnoe has helped me to become not only a better scientist but a better person as well. Even when I hit a very low point for about 6 months he never gave up on me. Due to the combination of his scientific knowledge, passion for chemistry, drive and patience, I do not think I could have done this without him. Others I would like to acknowledge from my time at NC State include Dr. Dave Schultz whose passion in the classroom for chemistry is very contagious (keep it up!), and Dr. Elon Ison and Dr. Reza Ghiladi who both took the time to give me kind and encouraging compliments (sometimes an occasional pat on the back is exactly what you need in grad. school). Dr. Jim Martin who I owe a special debt of gratitude to since if I had not met him I may not have discovered NC State, and in addition to many other things he did for my career he always made me feel welcome and like I was apart of the department. Prior to NC State, I had the pleasure to work with another great chemist/teacher, Dr. Greg Grant. Dr. Grant had, and continues to have, a large impact on my academic career. At iv a primarily undergraduate school, the research program that he runs is nothing less than astounding and working with Dr. Grant had a large impact on me. Since leaving UTC, we still keep in contact, and he still takes time to keep up with my career and give me much appreciated advice and guidance. In addition, I still keep in contact with the faculty of UTC at professional meetings, and even now (5 years after leaving) they still give me generous and much appreciated advice. Others that I would like to thank for their invaluable help during my graduate career include Dr. Tom Cundari, Dr. Paul Boyle and Dr. Jeff Petersen. If not for Dr. Cundari, our collaborator at the University of North Texas, one of my papers may not have even been published and the others would not have taught the scientific community nearly as much without his contributions. Dr. Paul Boyle (NC State) and Dr. Jeff Petersen (West Virginia University) have solved several crystal structures to contribute to this work, and just as importantly (if not more) they were always willing to take a look at my samples even when they weren’t that great. Last but definitely not least I would like to thank both the present and past students of the Gunnoe group I have had the privilege of working with. This includes: Dave Conner, Jubo Zhang, Marty Lail, Liz Blue, Karl Pittard, Yuee Feng, Colleen Munro-Leighton, Sam Delp, Ty Sumiyoshi, Nick Foley, Josh Gurkin, Joanna Webb and Brad McKeown. It truly was my pleasure working with each of you. For present group members, don’t lose track of what you are apart of in Dr. Gunnoe’s group and continue to strive to make the group stand out as one of a kind. v Table of Contents List of Figures ........................................................................................................................ viii List of Tables .......................................................................................................................... xii List of Schemes ...................................................................................................................... xiii Chapter 1: Introduction ........................................................................................................ 1 1.1 Organometallic Chemistry and Homogeneous Catalysis ......................................... 1 1.2 Fossil Resources as Our Primary Raw Material Source ........................................... 2 1.3 Hydroarylation of Olefins ......................................................................................... 5 1.4 Current Methods for C-C Bond Formation Involving Aromatic Substrates............. 5 1.4.1 Friedel-Crafts Catalysis .................................................................................... 5 1.4.2 Solid-State Catalysis ........................................................................................
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