William J. Evans

Picture of William J. Evans
UC Irvine Distinguished Professor, Chemistry
School of Physical Sciences
Ph.D., University of California, Los Angeles, 1973
Phone: (949) 824-5174
Fax: (949) 824-2210
Email: wevans@uci.edu
University of California, Irvine
2046B Frederick Reines Hall
Mail Code: 2025
Irvine, CA 92697
Research Interests
Inorganic and Organometallic Chemistry; Rare Earth, Actinide, and Bismuth Metal Chemistry
Academic Distinctions
Appointed UCI Distinguished Professor
Tolman Award of the Southern California Section of the American Chemical Society (SCALACS), 2015
American Chemical Society Award in Organometallic Chemistry 2015
M. F. Hawthorne Lecturer, UCLA 2014
Inaugural UCI Department of Chemistry Eminent Lecturer 2013
Terrae Rarae Award of the Tage der Seltenen Erden 2010
Elected Fellow of the Royal Society of Chemistry (FRSC) 2009
Spedding Award for Excellence in the Science and Technology of Rare Earths 2008
Elected Fellow of the American Association for the Advancement of Science 2008
Sir Edward Frankland Prize of the Royal Society of Chemistry 2007
UCI Distinguished Faculty Award for Research 2006
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
Research Abstract
The lanthanide and actinide metals represent extremes in the periodic table in terms of their unusual f valence orbitals, large size, high charge, and electropositive nature. This combination of features offers exciting opportunities to attack important problems in chemistry in new ways. The Evans group is exploring the chemistry of the rare earth metals, the actinides, and bismuth to determine how their unique properties can be developed to solve critical problems in the world.

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 quickly find alternatives to fossil fuels for generating energy. We must also address the problems of the carbon and nitrogen oxides that contaminate our environment. Interim solutions like nuclear power and the long term option of solar conversion of water to hydrogen need to be pursued vigorously.

We are developing the chemistry of the rare earth metals and the actinides to provide "out-of-the-box" approaches to these important problems. We are also pursuing the chemistry of bismuth, an under-developed metal similar in size to the lanthanides, to find new alternatives to solar water splitting.

The fact that the rare earth metals and actinides have been historically under-explored and constitute a frontier area of the periodic table means that these efforts directed to energy and the environment can also provide important advances in other areas. This includes topics as diverse as small molecule activation, catalysis related to the hydrogen economy, organic synthesis, and polymerization catalysis. The Center for Tissue Engineering is involved broadly with these metals in the pursuit of these goals and students get training in synthesis, mechanistic studies, structural analysis, physical property characterization, and inorganic, organometallic, organic and macromolecular reaction chemistry.

One general theme in the group is to develop new approaches to reduction chemistry. Acid base and redox reactions are the two most general reactions in chemistry and one would think they are fully developed. However, in recent years using the lanthanides and actinides, several new approaches to reduction have been discovered.

In one area, unprecedented multi-electron reductants capable of 2-,3-,4-,6-, and 8-electron reductions obtainable from a single molecule have been identified. Developing new understanding of multi-electron reduction is critical to the multi-electron solar water splitting reaction.

Another reductive approach involves the unusual use of steric effects to enhance redox chemistry. For decades, metal complexes containing three pentamethylcyclopentadienyl ligands, i.e. (C5Me5)3M, 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 reductive chemistry with small molecules, specifically dinitrogen and nitric oxide, have demonstrated the power of the f metal approach to new chemistry. We have recently isolated the first example of the (N2)3- ligand. Despite decades of research world-wide on dinitrogen reduction to make ammonia for fertilizer, no one had isolated dinitrogen at this level of reduction. It was possible to isolate the highly reactive (N2)3- radical, dubbed "supernitride" in the media since it is isoelectronic with superoxide, by using the special properties of the rare earth metals.

Exploration of the reactivity of the (N2)3- ion for the first time has led to another unique diatomic ion, (NO)2-. Again, despite decades of research on NO, due to its importance in atmospheric and biological chemistry, the doubly reduced ion, also a reactive radical, had not been previously identified.

It is remarkable that new forms of simple diatomic molecules can still be discovered. These results are very encouraging in terms of exploring the chemistry of these metals.

The impact of the discovery of the (N2)3- ion is just being determined, but it already has been found to be useful in the area of single molecule magnets (SMM). This ion couples highly paramagnetic ions like Dy3+ to make bimetallic complexes that function as single molecule magnets with the highest magnetic blocking temperature observed to date.

Efforts to explore the dinitrogen reduction have led to the identification of nine(!) new oxidation states for the rare earth metals, uranium, and thorium. It was a big surprise to find the first examples of complexes of these metals in the +2 oxidation state since the limits of the oxidation states of the elements have been tested for many decades. The new oxidation states exhibit unusual reactivity and the highest magnetic moments ever observed for a mono-metallic complex.
For a full publication list, see Evans Group Publications
"Record High Single-Ion Magnetic Moments through 4fn5d1 Electron Configurations in the Divalent Lanthanide Complexes [(C5H4SiMe3)3Ln] "Katie R. Meihaus, Megan E. Fieser, Jordan F. Corbey, William J. Evans, and Jeffrey R. Long, Journal of the American Chemical Society 2015, 137, 9855-9860. DOI: 10.1021/jacs.5b03710
"Synthesis, Structure, and Reactivity of Crystalline Molecular Complexes of the {[C5H3(SiMe3)2]3Th}1- Anion Containing Thorium in the Formal +2 Oxidation State" Ryan R. Langeslay, Megan E. Fieser, Joseph W. Ziller, Filipp Furche and William J. Evans Chemical Science, 2015, 6, 517–521. DOI: 10.1039/c4sc03033h
“Identification of the +2 Oxidation State for Uranium in a Crystalline Molecular Complex, [K(2.2.2-cryptand)][(C5H4SiMe3)3U]” Matthew R. MacDonald, Megan E. Fieser, Jefferson E. Bates, Joseph W. Ziller, Filipp Furche, and William J. Evans, Journal of the American Chemical Society 2013, 135, 13310–13313.
“Completing the Series of +2 Ions for the Lanthanide Elements: Synthesis of Molecular Complexes of Pr2+, Gd2+, Tb2+, and Lu2+” Matthew R. MacDonald, Jefferson E. Bates, Joseph W. Ziller, Filipp Furche, and William J. Evans, Journal of the American Chemical Society 2013, 135, 9857-9868.
“Isolation of (CO)1- and (CO2)1- Radical Complexes of Rare Earths via Ln(NR2)3/K Reduction and [K2(18-crown-6)2]2+ Oligomerization” Ming Fang, Joy H. Farnaby, Joseph W. Ziller, Jefferson E. Bates, Filipp Furche, and William J. Evans, Journal of the American Chemical Society 2012, 134, 6064-6067.
“Insertion of CO2 and COS into Bi–C Bonds: Reactivity of a Bismuth NCN Pincer Complex of an Oxyaryl Dianionic Ligand, [2,6-(Me2NCH2)2C6H3]Bi(C6H2tBu2O)” Douglas R. Kindra, Ian J. Casely, Megan E. Fieser, Joseph W. Ziller, Filipp Furche, and William J. Evans, Journal of the American Chemical Society 2013, 135, 7777-7787.
“An N23– Radical-Bridged Terbium Complex Exhibiting Magnetic Hysteresis at 14 K” Jeffrey D. Rinehart, Ming Fang, William J. Evans, and Jeffrey R. Long, Journal of the American Chemical Society 2011, 133, 14236-14239.
Strong Exchange and Magnetic Blocking in N23--Radical-Bridged Lanthanide Complexes” Jeffrey D. Rinehart, Ming Fang, William J. Evans, and Jeffrey R. Long, Nature Chemistry, 2011, 3, 538-542.
"Facile Bismuth-Oxygen Bond Cleavage, C-H Activation, and Formation of a Monodentate Carbon-Bound Oxyaryl Dianion, (C6H2tBu2-3,5-O-4)2-" Ian J. Casely, Joseph W. Ziller, Ming Fang, Filipp Furche, and William J. Evans, Journal of the American Chemical Society, 2011, 133, 5244-5247.
"Isolation of a Radical Dianion of Nitrogen Oxide (NO)2-" William J. Evans, Ming Fang, Jefferson E. Bates, Filipp Furche, Joseph W. Ziller, Matthew D. Kiesz, and Jeffrey I. Zink, Nature Chemistry, 2010, 2, 644.

"Isolation of Dysprosium and Yttrium Complexes of a Three-Electron Reduction Product in the Activation of Dinitrogen, the (N2)3- Radical" William J. Evans, Ming Fang, Gael Zucchi, Filipp Furche, Joseph W. Ziller, Ryan M. Hoekstra, and Jeffrey I. Zink, Journal of the American Chemical Society, 2009, 131, 11195.

"Reactivity of (C5Me5)3LaLx Complexes:  Synthesis of a Tris(pentamethylcyclopentadienyl) Complex with Two Additional Ligands, (C5Me5)3La(NCCMe3)2" William J. Evans, Thomas J. Mueller, and Joseph W. Ziller, Journal of the American Chemical Society, 2009, 131, 2678.

"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.

"Trivalent [(C5Me5)2(THF)Ln]2(µ-eta2:eta2-N2) Complexes as Reducing Agents Including the Reductive Homologation of CO to a Ketene Carboxylate, (µ-eta4-O2C-C=C=O)2-" William J. Evans, David S. Lee, Joseph W. Ziller, and Nikolas Kaltsoyannis Journal of the American Chemical Society 2006, 128, 14176-14184.
"Molecular Octa-Uranium Rings with Alternating Nitride and Azide Bridges" William J. Evans, Stosh A. Kozimor. and Joseph W. Ziller, Science 2005, 309, 1835-1838.
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