Charles P. Casey

Professor
B.S. 1963, St. Louis University
Ph.D. 1967, Massachusetts Institute of Technology

Room: 6112a
Phone: 608-262-0584
Email: casey@chem.wisc.edu
Position: Emeritus Professor

Research Description

My research group is interested in studying the mechanisms of organometallic reactions and in developing an understanding of homogeneous catalysis.

Reductions Catalyzed by Metal Complexes with Both Hydridic and Acidic Hydrogens.

For many years, we have sought to find reagents capable of simultaneously delivering a hydridic hydrogen and a protic hydrogen to polar molecules. Our initial efforts involved hertobimetallic hydrides. More recently, we initiated studies of the diruthenium hydrogenation catalysts discovered by Youval Shvo. The proposed key intermediate (C5Ph4OH)Ru(CO)2H has an electronically coupled acidic OH unit and a hydridic RuH unit. We have found that aldehydes are reduced by simultaneous transfer of H+ from OH and H- from RuH, this occurs outside the coordination sphere of the metal. We have developed improved iron hydrogenation catalysts and are now attempting to make enantioselective variants of the iron catalysts.



Hydroformylation with Chelating Diphosphines with Wide Natural Bite Angles Near 120 Degrees

Chelating diphosphines with large P-M-P bite angles near 120 degrees are interesting in the development of catalysts with controlled local geometry. In rhodium catalyzed hydroformylation, the key HRh(CO)2L2 catalysts are known to be mixtures of diequatorial diphosphine and equatorial-apical diphosphine complexes. We set out to test the hypothesis that very different regioselectivities of aldehyde formation might be obtained from diequatorial diphosphine rhodium complexes and from equatorial-apical diphosphine rhodium complexes. We found a strong correlation between regioselectivity for n-aldehyde formation and natural bite angle. Chelates like BISBI with wide natural bite angles gave a much higher % n-aldehyde than diphosphines with narrow bite angles.

Last updated October 8, 2008.

Publications

• "Spectroscopic Determination of Hydrogenation Rates and Intermediates during Carbonyl Hydrogenation Catalyzed by Shvo's Hydroxycyclopentadienyl Diruthenium Hydride Agrees with Kinetic Modeling Based on Independently Measured Rates of Elementary Reactions." Casey, C. P.; Beetner, S. E.; Johnson, J. B. J. Am. Chem. Soc. 2008,130, 2285-2295.

• "Intramolecular Trapping of an Intermediate in the Reduction of Imines by a Hydroxycyclopentadienyl Ruthenium Hydride: Support for a Concerted Outer Sphere Mechanism." Casey, C. P.; Clark, T. B.; Guzei, I. A. J. Am. Chem. Soc. 2007,129, 11821-11827.

• "An Efficient and Chemoselective Iron Catalyst for the Hydrogenation of Ketones." Casey, C. P. and Guan, H. J. Am. Chem. Soc. 2007, 129, 5816-5817.

• "Hydrogen Elimination from a Hydroxycyclopentadienyl Ruthenium(II) Hydride: Study of Hydrogen Activation in a Ligand-Metal Bifunctional Hydrogenation Catalyst." Casey, C. P.; Johnson, J. B.; Singer, S. W.; Cui, Q. J. Am. Chem. Soc. 2005, 127, 3100-3109.

• "Reversal of Enantioselectivity in the Hydroformylation of Styrene with [2S,4S-BDPP]Pt(SnCl₃)Cl at High Temperature Arises from a Change in the Enantioselective Determining Step." Casey,* C.P.; Martins, S. C.; Fagan, M. A. J. Am. Chem. Soc. 2004, 126, 5585-5592.

• "Hydrogen Transfer to Carbonyls and Imines from a Hydroxycyclopentadienyl Ruthenium Hydride: Evidence for Concerted Hydride and Proton Transfer." Casey, C. P. Singer, S. W. Powell, D. R., Hayashi, R. K., Kavana, M. . J. Am. Chem. Soc. 2001, 123, 1090-1100.

• " Direct Observation of a Non-chelated Metal-Alkyl-Alkene Complex and Measurement of the Rate of Alkyl Migration to a Coordinated Alkene." Casey, C. P.; Lee, T.-Y.; Tunge, J. A.; Carpenetti II, D. W. J. Am. Chem. Soc. 2001, 123, 10762-10763.

• "Synthesis and Spectroscopic Characterization of the d⁰ Transition Metal Alkyl-Alkene Complex Cp*₂YCH₂CH₂C(CH₂)2CH=CH₂." Casey, C. P.; Hallenbeck, S. L.; Pollock, D. W.; Landis, C. R. J. Am. Chem. Soc., 1995, 117, 9770-9771.

• "Diphosphines with Natural Bite Angles Near 120˚ Increase Selectivity for n-Aldehyde Formation in Rhodium-Catalyzed Hydroformylation." Casey, C. P.; Whiteker, G. T.; Melville, M. G.; Petrovich, L. M.; Gavney, J. A., Jr.; Powell, D. R. J. Am. Chem. Soc. 1992, 114, 5535-5543.

• "Reactions of (Diphenylcarbene)pentacarbonyltungsten(0) with Alkenes. Role of Metal-Carbene Complexes in Cyclopropanation and Olefin Metathesis Reactions." Casey, C. P.; Burkhardt, T. J. J. Am. Chem. Soc. 1974, 96, 7808.

Awards

• Hilldale Award in the Physical Sciences, University of Wisconsin, 2006

• National Science Council Distinguished Lecturer, Taiwan 1994

• Fellow, American Academy of Arts and Sciences, 1993

• Member National Academy of Sciences, 1993

• Fellow, American Association for Advancement of Science, 1991

• ACS Award in Organometallic Chemistry, 1991

• A.C. Cope Scholar Award, American Chemical Society, 1988

• Alexander von Humboldt Senior Award, 1988

• Japan Society for the Promotion of Science Fellowship, 1988

• Alumni Merit Award, St. Louis University, 1987