• Light-induced changes in molecular crystals
• Experimental mapping of the distribution of electrons
• Supramolecular chemistry and Crystal Engineering
• Quantumchemical calculations of molecular processes

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Coppens Research Group

732 Natural Sciences Complex Department of Chemistry University at Buffalo The State University of New York Buffalo, NY 14260-3000 Phone: (716) 645-6800 ext. 2217 Fax: (716) 645-6963 E-mail: coppens@buffalo.edu

• B. S., University of Amsterdam, The Netherlands (1954)
• Ph.D., University of Amsterdam (1960)
• Doct. Hon. Causa, University of Nancy, France (1989)
• Corr. Member, Royal Dutch Academy of Sciences

1. Studies of Laser-Generated Transient States by X-ray Diffraction and Infrared Spectroscopy.
2. Spectroscopy and Crystallography of Metastable States of Transition Metal Nitrosyl Complexes.
3. Use of Synchrotron Radiation in Crystallography.
4. Experimental Mapping of the Electron Density in Biomolecules.
5. Theoretical Calculations on Transition Metal Complexes and Small Peptides.

Our work combines crystallography, chemical synthesis, theoretical chemistry and spectroscopy in a comprehensive approach to chemical research. It includes the development of new methods for the study of solids by X-ray diffraction and spectroscopy. Using synchrotron radiation and excitation by laser-light at low temperature we determine the geometry of molecular species that exist for only microseconds or less. We also study chemical reactions in complex solids and examine how the molecule changes and the kinetics of change as the reaction proceeds.

We use the methods of crystal engineering to synthesize new supramolecular solids. They are used to study the properties of molecules embedded as guest in the cavities of molecular frameworks. As in solutions this allows molecular dilution, but with the distinction that a periodic array is maintained.

As X-rays are scattered by the electrons, X-ray diffraction can be used to map the electron distribution in solids, thus shedding light on the chemical bonding in molecules. Recently, we have focused attention on the derivation of the electrostatic potential and other electrostatic properties, such as dipole and quadrupole moments. The electrostatic properties are of importance for the understanding of chemical reactivity, the lattice energy of crystals, the folding of biological macromolecules, and the interactions between enzymes and substrates.

Selected Recent Publications