Toward the Upgrading of Hydrocarbons: Synthesis, Characterization, and Reactivity of Platinum and Palladium Complexes Thesis by Paul Frederick Oblad In Partial Fulfillment of the Requirements for the degree of Doctor of Philosophy CALIFORNIA INSTITUTE OF TECHNOLOGY Pasadena, California 2012 (Defended August 26, 2011) 2012 Paul Frederick Oblad All Rights Reserved ii Acknowledgements I have so many people to thank for their role in my education. First and foremost, I have all of my advisors to mention. John Bercaw and Harry Gray have been very generous in letting me join their groups as a refugee from Jonas Peters’ group. John has been a great advisor, as he provided both direction and supervision when I needed it and freedom to pursue my interests when I was so inclined. Harry has been an eternal optimist and always providing me much needed direction and support. He taught me to laugh at my mistakes and, more importantly, how to correct them. I feel that I would not have been able to learn as much as I have from John and Harry if I had worked for any other advisor. I am also tremendously grateful to Jay Labinger. Though he was not officially responsible for me, he gave his time like he was. Jay was always available when I had questions and was able to answer those questions in a way that even I could understand. Jay Winkler was also an unofficial advisor that generously gave his time. His door was always open to me and he would patiently answer all of my questions. Also, even though he was only my advisor for a short time, I am very grateful to Jonas Peters for his role in my education. He even got me a fellowship for my first year. I am grateful for the opportunities he has given me and the time I spent in his lab. I would also like to thank other members of my committee, Nate Lewis and Mitchio Okumura for valuable guidance and for bearing with me while I tried to coordinate the busy schedules of all six of those on my panel. I am very grateful to Bruce Brunschwig and Jack Richards for coming to my group meetings and giving me valuable advice. Additionally, Tom Richmond, my advisor at the University of Utah, originally got me excited about chemistry and is why I ended up in graduate school. iii Secondly, I would like to thank all the students and postdocs with whom I worked closely. Travis Williams taught me many of the laboratory techniques that I use most. I thoroughly enjoyed working with him, learning from him and listening to his puns. I have always strived not to ―cross the streams‖ for fear of ―total protonic reversal‖ (Ghostbusters). Unfortunately, most of my reactions resulted in what he termed a ―diversity oriented synthesis‖ (DOS) or ―the phonebook.‖ Nilay Hazari really taught me to think critically about chemistry. He always praised my work and made me feel that my contributions were valuable. I am a more confident and a harder worker because of him. Ted Weintrob has been a great friend during graduate school. We both were initially in the Peters group and subsequently moved to the Bercaw group. In the office our desks were always in the same section and for a while we shared the south half of 213 Noyes. We also had every class together. Though we never actually worked on the same project, Ted always talked to me about my project and made many valuable intellectual contributions. I also would take all the questions I was too embarrassed to ask anyone else to him first. More recently, Matt Winston has joined me on a few projects and impressed me with how motivated and smart he is. Matt’s work was instrumental in making these projects really take off and become interesting. These projects would not be anywhere near where they are without him. Jillian Dempsey taught me how to use the laser and very generously gave me more Ru(bipy)32+ and methyl viologen than she probably wanted to. Alec Durrell was very helpful with the laser and with photophysics. Though I tried to reciprocate and help him with some synthesis, he was much more helpful to me than I was to him. I not only iv benefited from working very closely with all of these people, I benefitted tremendously from their friendship. Thank you all for everything. There are a tremendous number of people with whom I was not fortunate enough to work closely with but to whom I am still very grateful. They either helped me with chemistry or otherwise supported me with their friendship. Alex Miller (a fellow Peters group refugee) was generous with his time when I had chemistry questions and is someone I look up to. I also really enjoyed dinners, camping and wine tasting with him and Jillian. Matt and Charlotte Whited were great sources of chemical expertise and fun to hang out with in our spare time. As our closest neighbors, they were always willing to join us for dinner or wine, babysit or carpool with us to the beach or movie night at the Durrell’s. I have already mentioned Alec but I spent many hours watching Star Trek, Battlestar Galactica, and Breaking Bad with him. Additionally, he and his wife, Cristina Durrell, often invited us to the beach or their pool. I am so grateful that Christian and Charlotte were very good friends with my wife, Stephanie. Ian Tonks always had great stories and included me in sporting events. Aaron Wilson was a great rock climbing buddy and was kind to try to help me get a job. Steve Baldwin was also very helpful with chemistry and was very kind to my family. He was always excited to play with my son, Liam, and spent the entirety of several social events doing just that. Nathan West was happy to kill aliens with me on Xbox 360 while his wife, Erin, and my wife did things that they found more interesting. Paul Elowe was very kind to help me get an interview with his company. Jeffrey Warren, Nicole Bouley Ford, and Bert Lai were very kind to look over my out-of- field proposals. Valerie Scott, Jeffery A. Byers, Theodor Agapie, George Chen, Suzanne v Golisz, Bolin Lin, David Weinberg, Ross Fu, Rachel C. Klet, Yan Choi Lam, Taylor Lenton, Emannuelle Despagnet-Ayoub, Amaruka Hazari, Carl Laskowski, Sze-Man Yu, Peter Agbo, Matthew Bierman, Paul Bracher, Maraia Ener, Gretchen Keller, Judith Lattimer, James McKone, Qixi Mi, Astrid Mueller, Josh Palmer, Mike Rose, Bryan Stubbert, Heather Williamson, Keiko Yokoyama, Morgan Cable, Lionel Cheruzel, Matthew Hartings, Tetsunari Kimura, Kyle Lancaster, Don Walker, and Melanie Yen all helped me at some point during my graduate career, for which I am very grateful. There are also a few Caltech staff member that were incredibly helpful. Larry Henling spent hours with me at the console of the X-ray diffractometer and became a very good friend of mine. Mike Day was always willing to work up even the worst data. Tom Dunn was very helpful for all my random electronics needs. David Vander Velde and Scott Ross taught me a great deal about NMR. Pat Anderson was always very friendly and willing to help with anything. Catherine May, Rick Jackson, Anne Penny, and Agnes Tong were very helpful with odds and ends. Finally, I want to thank my family. Stephanie has stuck with me through it all. She has supported me though the highs and lows. I really would have not made it through graduate school without her. Thank you, Steph. Liam has brought new meaning to life. He never ceases to amaze me. I am so fortunate to have such a great kid. My parents, Nan and Bruce, are amazing. My Dad taught me to think like a scientist and my Mom taught me what mattered in life. I don’t know how I can thank them enough. All my siblings, Rachel, Hayward, Mark, Stephen, John, Richard, and Bryant, and my mother-in-law, Gayle Hunt, have always been supportive and willing to do anything for me. There are so many vi people I should thank, I have inevitably left someone out and for that I apologize. Thank you all. vii Abstract Herein, hydroxyl-dimers of platinum and palladium supported by diimine ligands have been prepared and studied. It was found that they are capable of activating allylic, benzylic, and aromatic carbon-hydrogen bonds. The kinetics of the C-H activation of cyclohexene with the platinum system and of indene with the palladium system were studied. In each case the rate-limiting step was found to be associative substitution. The catalytic dehydrogenation of cyclohexene to benzene with the palladium hydroxyl-dimer was investigated. The chemical oxidation of the η3-organometallic products synthesized via C-H activation of cyclohexene and indene with platinum and palladium, respectively, was explored. Treatment of these products with strong halogenating oxidants resulted in the liberation of halogenated substrates and bridging halide metal complexes. Uncharged platinum and palladium polypyrazoleborate complexes were synthesized and characterized. The kinetics of the degenerative ligand exchange of DMSO with palladium methyl DMSO complexes ligated with a polypyrazoleborate or a diimine ligand were studied and it was found that the associative substitution mechanism through which the diimine ligated complexes proceeds was unavailable to the polypyrazoleborate palladium complex. In the polypyrazoleborate system ligand exchange proceeded through a dissociative mechanism. The C-H activation substrate scope of the platinum and palladium hydroxyl-dimers was further explored. The diimine platinum hydroxyl-dimer was found to activate an allylic C- H bond in cyclopentene and form an η3-cyclopentenyl complex when heated with acid and dilute stoichiometric amounts of cyclopentene.