William J. EvansProfessor, Chemistry |
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Research Interests |
Inorganic and Organometallic Chemistry | |
| URL | Group Web Page (http://www.chem.uci.edu/~wevans/) | |
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Academic Distinctions |
2008 Spedding Award for Excellence in the Science and Technology of Rare Earths Sir Edward Frankland Prize of the Royal Society of Chemistry, 2007 American Chemical Society Award in Inorganic Chemistry 2005 National Science Foundation Special Creativity Award 2004 UCI Physical Science Award for Outstanding Contributions to Undergraduate Education 2002 Alfred P. Sloan Fellow Camille and Henry Dreyfus Foundation Teacher-Scholar Chair, Gordon Research Conference on Inorganic Chemistry 1993 Peter C. Reilly Lecturer, University of Notre Dame 1992 Fishel Lecturer, Vanderbilt University 1999 Frontiers in Chemical Research Lecturer, Texas A&M University 2002 |
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| Appointments | Research Associate, Cornell University | |
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Research Abstract |
Lanthanides constitute one of the last frontiers in the periodic table. These historically underdeveloped metals offer exciting opportunities to attack important problems in chemistry in new ways. The Evans group is exploring the chemistry of these metals to determine how their unique properties can be developed to solve critical problems in the world. Of greatest current interest is the development of sustainable energy sources alternative to the fossil fuels. Current predictions of the environmental impact of increasing the levels of carbon dioxide in our atmosphere from burning oil, gas, and coal indicate that we must find alternatives quickly. Interim nuclear power and ultimate solar conversion of water to hydrogen need to be pursued vigorously. As described below, the f elements offer "out-of-the-box" approaches to these important problems in addition to topics as diverse as small molecule activation (N2, CO, CO2, NO, CH4), catalysis related to the hydrogen economy, organic synthesis, and polymerization catalysis. To achieve these goals, the Evans lab is involved in the synthesis, mechanistic studies, structural analysis, physical property characterization, and macromolecular chemistry of the f elements and closely related yttrium and bismuth. For example, we have recently used the lanthanide and actinide metals to reveal new approaches to reduction, one of the fundamental reactions in chemistry. This has allowed the development of unprecedented multi-electron reductants capable of 2,3,4,6, and 8 electron reductions depending on the substrate. Developing new understanding of multi-electron reduction is critical to the multi-electron solar water splitting reaction. One new reductive approach involved the synthesis of the first metal complexes containing three pentamethylcyclopentadienyl ligands. For decades, these (C5Me5)3M complexes were thought to be too sterically crowded to exist. After we isolated the first examples, we discovered that these molecules were reducing agents even though they contained redox inactive metals! We call this phenomenon sterically induced reduction and we are studying its mechanisms and implications. By exploring uranium and thorium along with the lanthanides we seek to develop comparative information on the lanthanides vs actinides that will be helpful in the Advanced Nuclear Energy Systems (ANES) project of the Department of Energy. Our studies are oriented to aid in nuclear fuel synthesis and waste stream separation. Recent efforts in small molecule activation have shown that dinitrogen can be reduced by lanthanides to make (N2)2- ligands that display an unusual planar M2N2 unit that can reductively homologate three equivalents of CO to a ketene carboxylate (O2C-C=C=O)2- in which a CO triple bond has been completely cleaved. In the area of organic synthesis, we identified the first planar bridged trimethylenemethane dianion, [C(CH2)3]2-, and we have found an unexpected route to triazoles from diazo compounds and nitriles. The lanthanides also have unique potential in catalytic polymerization chemistry. They are among the best catalysts for the formation of biodegradable polymers from lactones and synthetic rubber from isoprene. Our group is studying these successful catalyses, since they offer great opportunities to identify new aspects of fundamental organometallic chemistry. The special physical properties of the lanthanides make them useful in a variety of devices, e.g. the energy efficient red europium luminescence in optical displays and the oxygen storage capacity of cerium in catalytic converters in automobiles. The group is studying new synthetic methods to incorporate the lanthanides into these materials in a more efficient and homogeneous manner. |
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| Publications | "Multi-Electron Reduction from Alkyl/Hydride Ligand Combinations in U4+ Complexes" William J. Evans, Elizabeth Montalvo, Stosh A. Kozimor, and Kevin A. Miller, Journal of the American Chemical Society, 2008, 130, 12258-12259. | |
| “A Crystallizable f-Element Tuck-In Complex: the Tuck-In Tuck-over Uranium Metallocene (C5Me5)U[µ-η5:η1:η1-C5Me3(CH2)2](µ-H)2U(C5Me5)2" William J. Evans, Kevin A. Miller, Antonio G. DiPasquale, Arnold L. Rheingold, Timothy J. Stewart, and Robert Bau, Angewandte Chemie International Edition 2008, 47, 5075-5078. | ||
| "The Importance of Questioning Scientific Assumptions: Some Lessons from f Element Chemistry" Evans WJ Inorganic Chemistry 2007, 46, 3435. | ||
| "Actinide Hydride Complexes as Multielectron Reductants: Analogous Reduction Chemistry from [(C5Me5)2UH]2, [(C5Me5)2UH2]2, and [(C5Me5)2ThH2]2" Evans WJ, Miller KA, Kozimor SA, Ziller JW, DiPasquale AG, Rheingold AL Organometallics 2007, 26, 3568. | ||
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"C-H Bond Activation Via Steric Crowding of Normally Inert Ligands in the Sterically Crowded Gadolinium and Yttrium (C5Me5)3M Complexes" Evans, W. J.; Davis, B. L.; Champagne, T. M.; Ziller, J. W. Proceedings of the National Academy of Science, 2006, 103, 12678-12683. |
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“Organolutetium Vinyl and Tuck-Over Complexes via C-H Bond Activation” Evans, W. J.; Champagne, T. M.; Ziller, J. W. Journal of the American Chemical Society 2006, 128, 14270-14271. |
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"Trivalent [(C5Me5)2(THF)Ln]2(µ-η2:η2-N2) Complexes as Reducing Agents Including the Reductive Homologation of CO to a Ketene Carboxylate, (µ-η4-O2C-C=C=O)2-" Evans, W. J.; Lee, D. S.; Ziller, J. W.; Kaltsoyannis, N. Journal of the American Chemical Society 2006, 128, 14176-14184. |
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| "Planar Trimethylenemethane Dianion Chemistry of Lanthanide Metallocenes: Synthesis, Structure, Density Functional Theory Analysis, and Reactivity of [(C5Me5)2Ln]2(µ-η3:η3-C(CH2)3] Complexes" Evans, W. J.; Champagne, T. M.; Ziller, J. W.; Kaltsoyannis, N. Journal of the American Chemical Society 2006, 128, 16178-16189. | ||
| "Formation of a Bridging Planar Trimethylenemethane Dianion from a Neopentyl Precursor Via Sequential β-Alkyl Elimination and C-H Activation" Evans WJ, Perotti JM, Ziller JW Journal of the American Chemical Society 2005, 127,1068. | ||
| "Molecular Octa-Uranium Rings with Alternating Nitride and Azide Bridges" Evans WJ, Kozimor SA, Ziller JW Science 2005, 309, 1835. | ||
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Synthetic Utility of [(C5Me5)2Ln][(µ-Ph)2BPh2] in Accessing [(C5Me5)2LnR]x Unsolvated Alkyl Lanthanide Metallocenes, Complexes with High C-H Activation Reactivity" Evans WJ, Perotti JM, Ziller JW Journal of the American Chemical Society 2005, 127, 3894. |
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| "Structure, Reactivity, and Density Functional Theory Analysis of the Six Electron Reductant, [(C5Me5)2U]2(µ-η6:η6-C6H6), Synthesized Via a New Mode of (C5Me5)3M Reactivity” Evans WJ, Kozimor SA, Ziller JW, Kaltsoyannis N J. Am. Chem. Soc. 2004, 126, 14533. | ||
| "Expanding Dinitrogen Reduction Chemistry to Trivalent Lanthanides via the LnZ3/AlkaliMetal Reduction System: Evaluation of the Generality of Forming Ln2(µ-η2:η2-N2) Complexes via LnZ3/K" Evans WJ, Lee DS, Rego DB, Perotti JM, Kozimor SA, Moore EK, Ziller JW J. Am. Chem. Soc. 2004, 126, 14574. | ||
| "Polymerization of Isoprene by a Single Component Lanthanide Catalyst Precursor." Evans WJ, Giarikos DG, Allen NT Macromolecules 2003, 36, 4256. | ||
| "The Chemistry of Tris(pentamethylcyclopentadienyl) f Element Complexes, (C5Me5)3M." Evans WJ, Davis BL Chem. Rev. 2002, 102, 2119. | ||
| "The Availability of Dysprosium Diiodide as a Powerful Reducing Agent in Organic Synthesis: Reactivity Studies and Structural Analysis of DyI2(DME)3 and Its Naphthalene Reduction Product." Evans WJ, Allen NT, Ziller JW J. Am. Chem. Soc. 2000, 122, 11749. | ||
| Link to this profile | http://www.faculty.uci.edu/profile.cfm?faculty_id=2024 | |
| Last updated | 11/11/2008 | |