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Chemistry and Biochemistry
University of California
230 Physical Sciences Bldg.
Santa Cruz, CA 95064
Phone: (831) 459-4002
Fax: (831) 459-2935
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Claude Bernasconi Professor of Chemistry B.S., M.S., Ph.D., Swiss Federal Institute of Technology, Zürich Office: 350 PSB Phone: (831) 459-2035 Fax: (831) 459-2935 claude@chemistry.ucsc.edu

Bernasconi Research Group Department of Chemistry University of California 1156 High Street Santa Cruz, CA 95064 Office Hours Class Times & Locations Labs: 386/390 PSB, 9-4124 Bernasconi Research Group

RESEARCH INTERESTS: Physical and Mechanistic Organic Chemistry and Organometallic Chemistry, Chemical Reactivity, Kinetics, Ab Initio Calculations

The main research interests of Claude Bernasconi, described in more detail on The Bernasconi Research Group Home Page, center on problems of mechanism, structure-reactivity relationships, intrinsic barriers of reactions, and catalysis in organic and organometallic reactions. Specifically he would like to improve our understanding of why certain reactions have high activation barriers while others have low barriers even though their thermodynamic driving force may be the same. This is one of the most fundamental questions one may ask about a chemical process. The specific reactions which are under current study include proton transfers and reactions of nucleophiles with electrophiles such as activated olefins, vinylic compounds, and transition metal carbene complexes. Main research tools comprise a variety of kinetic methods, including fast-reaction techniques such as the stopped-flow and the temperature-jump relaxation methods, and also computational methods. Bernasconi’s considerable expertise in the use of kinetic methods has led him to write the book Relaxation Kinetics, and he is the editor of the most recent edition of Investigation of Rates and Mechanisms of Reactions, in the series Techniques of Chemistry. More recently, Bernasconi's research has expanded into ab initio molecular orbital calculations of transition states of proton transfer processes.

Bernasconi has been an Alfred P. Sloan Fellow and has been elected a Fellow of the American Association for the Advancement of Science. He has enjoyed continuous support from the National Science Foundation.

SELECTED PUBLICATIONS

C. F. Bernasconi and M. Pérez-Lorénzo, “Does Aromaticity in a Reaction Product Increase or Decrease the Intrinsic Barrier? Kinetics of the Reversible Deprotonation of Benzofuran-3(2H)-one and Benzothiophene-3(2H)-one,” J. Am. Chem. Soc. 129, 2704-2712 (2007).

C. F. Bernasconi, M. E. Zoloff Michoff, and R. H. de Rossi, “Kinetics of the Reaction of [p-Nitrophenoxy(phenyl)carbene]pentacarbonylchromium (0) with Aryloxide Ions, Hydroxide Ion and Water in Aqueous Acetonitrile,” J. Org. Chem. 72, 1285-1293 (2007).

C. F. Bernasconi, S. D. Brown, M. Ali, Z. Rappoport, H. Yamataka,  and H. Salim, “Hydrolysis of a-Alkyl-a-(methylthio)methylene Meldrum’s Acids. A Kinetic and Computational Investigation of Steric Effects,” J. Org. Chem. 71, 4795-4802 (2006).

C. F. Bernasconi, D. E. Fairchild, R. L. Montañez, P. Aleshi, H. Zheng and E. Lorance, “Kinetics of Proton Transfer from Cationic Carbon Acids in Water and Aqueous DMSO. Effect of Activating Groups and Solvent on Intrinsic Rate Constants,” J. Org. Chem. 70, 7721-7730 (2005).

C. F. Bernasconi, V. Ruddat, P. J. Wenzel, and H. Fischer, “Kinetic and Thermodynamic Acidities of Pentacarbonyl(cyclobutenylidene)chromium Complexes. Effect of Anti­aromaticity in the Conjugate Anion. An Experimental and Computational Study,” J. Org. Chem. 69, 5232-5239 (2004).

C. F. Bernasconi, “The Principle of Nonperfect Synchronization: How Does It Apply to Aromatic Systems?” J. Phys. Org. Chem. 17, 951-956 (2004).

C. F. Bernasconi, M. Ali and J. C. Gunter, “Kinetic and Thermodynamic Acidities of Substituted 1-Benzyl-1-methoxy-2-nitroethylenes. Strong Reduction of the Transition State Imbalance Compared to Other Nitroalkanes,” J. Am. Chem. Soc. 125, 151-157 (2003).

C. F. Bernasconi, M. L. Ragains, and S. Bhattacharya, “Reactions that Generate Aromatic Molecules: Is Aromatic Stabilization Less or More Advanced than Bond Changes at the Transition State? Kinetic and Thermodynamic Acidities of Rhenium Carbene Complexes,” J. Am. Chem. Soc. 125, 12328-12336 (2003).

C. F. Bernasconi, “The Physical Organic Chemistry of Fischer Carbene Complexes,” Adv. Phys. Org. Chem. 37, 137-237 (2002).

C. F. Bernasconi and P. J. Wenzel, “Carbon-to-Carbon Identity Proton Transfer from Propyne, Acetimide, Thioacetaldehyde and Nitrosomethane to Their Respective Conjugate Anions in the Gas Phase. An Ab Initio Study,” J. Org. Chem. 66, 968-979 (2001).