UNIVERSITY OF CALIFORNIA Santa Barbara Umpolung - The “Flow” from Oxidation to Reduction. A journey from cathodic carbon-carbon bond coupling reactions carried out in a flow reactor to the electrooxidative and photoreductive characteristics of phenanthroimidazole mediators. A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Chemistry by Chiu Marco Lam Committee in charge: Professor R. Daniel Little, Chair Professor Trevor W. Hayton Professor Liming Zhang Professor Javier Read de Alaniz Professor Lior Sepunaru June 2018 The dissertation of Chiu Marco Lam is approved. ____________________________________________ Professor Lior Sepunaru ____________________________________________ Professor Javier Read de Alaniz ____________________________________________ Professor Liming Zhang ____________________________________________ Professor Trevor W. Hayton ____________________________________________ Professor R. Daniel Little, Committee Chair June 2018 Umpolung - The “Flow” from Oxidation to Reduction. A journey from cathodic carbon-carbon bond coupling reactions carried out in a flow reactor to the electrooxidative and photoreductive characteristics of phenanthroimidazole mediators. Copyright © 2018 by Chiu Marco Lam iii Acknowledgements The research and writing of this dissertation took a long and tortuous path. Without the help and support of the people and institutions acknowledged here, I would not have been able to complete this study. While I bear sole responsibilities for the errors, omissions and imperfections in this dissertation, I am profoundly indebted to their guidance, generosity and forbearance. Words cannot express my gratitude to members of my dissertation committee, especially my advisor Prof. R. Daniel Little. Being a caring and prudent mentor, Prof. Little has been shaping my intellectual development since our first meeting. He has had no hesitation reading numerous versions of the manuscripts, and managed to provide insightful comments and edits however impractical my ideas and writing might have been. My other committee member, Prof. Trevor W. Hayton, has also helped shape my graduate study in its initial stage. With his expertise in organometallic chemistry and knowledge of inorganic chemistry, Prof. Hayton’s invaluable advice helped me lay down a much more solid groundwork for inorganic chemistry. And Prof. Lior Sepunaru, despite a relatively late invitation, still agreed to serve as a member of my committee. His input proved to be instrumental for this study to have a genuinely interdisciplinary perspective. Prof. Javier Read de Alaniz and Prof. Liming Zhang have also offered valuable opinions to my studies. A special thank goes to Prof. Chengchu Zeng, for hosting me in Beijing and providing intellectual discussions. My graduated study has been benefited greatly from researchers and institutions in the United States, China, and Germany. Beijing University of Technology, Johannes Gutenberg-University Mainz, and University of Rostock. Prof. Kevin Moeller have always been the source of inspiration and encouragement. I have also benefited greatly from iv discussion and working with Prof. Robert Francke, as well as Prof. Siegfried R. Waldvogel and his group. I would like to express my gratitude toward my friends and colleagues in UCSB especially the Little group, the Hayton group, the Sepunaru group and the Dow lab. Thank you very much for giving me the opportunity to teach and be taught, sharing laughter and tears. I would like to thank Kunliang Wu, Yenping Lin, Gloria Mo and Siuhoi Lui for the encouragements and brought me into research. I would like to thank Sheng Sun, Kin-kei Yim, James Chun-Pong Tam, and Stanley Fong for providing the consolation when I needed a break. I thank them for their close friendship and memories. I wish them all success. Last but not least, I would like to express my deepest gratitude towards my parents Chun-Kwong Lam and Siu-Yung Wong, my sister Yi, and my grandma Choi-Ying Cheng. Without your unwavering support and love, I would not be where I am today. I owe all of my success to you. v VITA OF CHIU MARCO LAM June 2018 EDUCATION University of California, Santa Barbara, CA Ph.D. in Chemistry (advisor: Prof. R. Daniel Little) 2018 University of California, Santa Barbara, CA B.S. in Biochemistry with a minor in History 2011 PROFESSIONAL TRAINING Researcher Assistant 2009 - 2018 Advisor: Professor R. Daniel Little, University of California, Santa Barbara Principle research foci: 1) Development and use of a microflow reactor, especially for problematic electroreductive coupling reactions. 2) The disassembly of lignin-related structures; the dual role of electron transfer mediators in electrochemical and photoredox chemistry. 3) Research directed toward the development of a new class of electrochemical redox mediators. 4) Research directed toward the dual catalyst properties and photo-reduction potentials of an electro-oxidation triarylimidazole mediators. Oversea graduate research in China Fall 2014 & Fall 2016 Mentor: Professor Cheng-Chu Zeng, Beijing University of Technology, China PIRE-ECCI Fellow; focus upon electron transfer chemistry achieved electrochemically. Teaching Assistant (UCSB) 2012 - 2018 Lectured, supervised and demonstrated experiments with safety instruction to general, organic labs, and physical organic classes. PRESENTATIONS AND CONFERENCES Electrode surface modification by electrografting using diazonium salts Indirect electrolysis of a lignin model, 1st Annual Meeting of Center for Sustainable Use of Renewable Feedstocks (CenSURF), UCSB. (Oral Presentation, 09/14/2013) TEMPO-scandium triflate oxidation of benzylic alcohols Two stage cleavage of lignin model systems, 2nd Annual Meeting of Center for Sustainable Use of Renewable Feedstocks (CenSURF), UCSB. (Oral Presentation and Poster, 08/21/2014) vi Electrochemical character and application of halide mediators using CF3CH2OH as solvent, 227th National Meeting of the Electrochemical Society, Chicago, IL. (Oral presentation, 5/28/2015) Selective and mild oxidation with TEMPO and scandium triflate, SoCal Organometallics Meeting, UC Riverside. (Poster, 12/05/2015) Electroreductive coupling reactions using a microflow reactor, 229th National Meeting of the Electrochemical Society, San Diego, CA. (Oral presentation, 5/30/2016) Electroreductive carbon-carbon bond coupling carried out in a flow reactor, Renewable Carbon Workshop, The Mellichamp Academic Initiative in Sustainability, UC Santa Barbara. (Poster, 9/6/2016) Photoredox Catalyst Based on a Triarylimidazole Oxidative Electrochemical Mediator, 231th National Meeting of the Electrochemical Society, New Orleans, LA. (Oral presentation, 5/29/2017) Photoredox Catalyst Based on a Triarylimidazole Oxidative Electrochemical Mediator, 50th Heyrovský Discussion, Třešť, Czech Republic. (Invited, Oral presentation, 6/18- 22/2017) Photoredox Catalyst Based on a Triarylimidazole Oxidative Electrochemical Mediator, 67th Annual Meeting of The International Society of Electrochemistry, Providence, RI. (Oral presentation, 8/31/2017) PUBLICATIONS 1. Zeng, C. C.; Zhang, N. T.; Lam, C. M.; Little, R. D. Novel triarylimidazole redox catalysts: synthesis, electrochemical properties and applicability to electrooxidative C-H activation, Org. Lett. 2012, 14, 1314-1317. 2. Zhang, N. T.; Zeng, C. C.; Lam, C. M.; Gbur, R. K.; Little, R. D. Triarylimidazole Redox Catalysts: Electrochemical Analysis and Empirical Correlations, J. Org. Chem. 2013, 78, 2104–2110. 3. Chen, J.; Yan, W. Q.; Lam, C. M.; Zeng, C. C.; Hu, L. M.; Little, R. D. Electrocatalytic Aziridination of alkenes mediated by n-Bu4NI: A Radical Pathway, Org. Lett. 2015, 4, 986-989. 4. Li, L. J.; Jiang, Y.Y.; Lam, C. M.; Zeng, C.C.; Hu, L. M.; Little, R. D. Aromatic C-H bond functionalization induced by electrochemically in situ generated tris(P- bromophenyl)aminium (TBPA) radical cation: cationic chain reactions of electron-rich aromatics with enamides, J. Org. Chem. 2015, 21, 11021-11030. 5. Kang, L. S.; Luo, M. H.; Lam, C. M.; Zeng, C. C.; Hu, L. M.; Little, R. D. Electrochemical C-H functionalization and subsequent C-S and C-N bond formation: paired electrosynthesis of 3-amino-2-thiocyanato-α,β-unsaturated carbonyl derivatives mediated by bromide ion, Green Chemistry, 2016, 18, 3767-3774. 6. Gao, W. J.; Lam, C. M.; Zeng, C. C.; Sun, B. G.; Little, R. D. Selective electrochemical C-O bond cleavage of -O-4 lignin model compounds mediated by iodide ion, Tetrahedron, 2017, 73, 2447-2454. 7. Lam, C. M.; Little, R. D.; Hayton, T. W.; Francke, R. On the Reactivity of TEMPO in the Presence of Lewis Acids: Tuning the Selectivity by Using Scandium Triflate, manuscript in preparation. vii 8. Lam, C. M.; Little, R. D.; Electroreductive carbon-carbon bond coupling carried out in a flow reactor, manuscript in preparation. 9. Lam, C. M.; Little, R. D.; Photoredox Catalyst Based on an Arylimidazole Oxidative Electrochemical Mediator, manuscript in preparation. FELLOWSHIPS AND AWARDS Center for Sustainable Use of Renewable Feedstocks (CENSURF) Fellowship. (2013- 2014) The Partnership in International Research and Education in Electron Chemistry and Catalysis at Interfaces (PIRE-ECCI) Fellowship & travel grants. (2014-2015) Roche Bioscience Distinguished Teaching Fellowship. (2015-2016) Mellichamp Sustainability Fellowship (2016) IRES-Research in China on Electron Chemistry and Catalysis at Interfaces Fellowship & travel grants. (2016) The Electrochemical Society (ECS)