Edwin D. Stevens Department Chair Distinguished Professor – Physical B.S., Oregon State 1969 Ph.D., UC Davis 1973 email: estevens@uno.edu phone: (504) 280-6856 office: CBS 116

Research Interests X-rays striking a crystal are scattered by the electrons in the crystal. This has long been used by crystallographers to determine the positions of atoms in crystals. If the measurements are accurately made, the distributions of valence electrons can be mapped as well. Features due to the formation of chemical covalent bonds, lone pairs, and non-bonding d-electrons are readily apparent in the electron distribution. Dr. Stevens has been involved in the development and application of this novel experimental method starting from some of the earliest studies; this is the central focus of his research. The experimental electron distribution yields direct information on chemical bonding applicable in such a variety of disciplines that the method transcends traditional classifications such as physical, inorganic, organic, and biochemistry, solid state physics, and materials science. Fundamental studies on small molecules demonstrate the charge distribution may be measured experimentally with an accuracy comparable to the most sophisticated theoretical calculations currently possible. Recent studies of transition metal complexes have shown that the effects of crystal field splitting are easily observable in the experimental charge distribution, and the experimental data can be analyzed to give the distribution of electrons among each of the d-orbitals. Metal clusters and complexes with metal-metal bonds are currently being studied to give experimental information on the electronic structure of complexes which may be involved in homogeneous catalysis and which may also serve as models for heterogeneous catalysis. Since little additional effort is required for large molecules, in contrast to theoretical calculations, charge distributions can be measured on large organic and biological molecules. Currently in progress are studies of various drugs to construct a model for drug-receptor interactions which includes both steric and charge distribution requirements. Also underway are stricture-activity studies of derivatives of gossypol, a toxin isolated from cotton seeds, in order to optimize anticancer activity. Other areas of Dr. Stevens' research interest include studies of metals, metal alloys, minerals, and compounds with unusual physical properties including high-temperature superconductivity, one dimensional electrical conductivity, and highly anharmonic motion. This research utilizes national X-ray synchrotron facilities which produce X-ray beams from high-energy electron storage rings which are 10,000 times more intense than those of conventional laboratory X-ray sources. These sources are expected to make entirely new experiments possible as well as greatly improving the accuracy of current experiments.

Selected Publications "Modified (NCH)Pd(allyl)Cl Complexes for Room Temperature Suzuki-Miyaura and Buchwald-Hartwig Reactions," N. Marion, O. Navarro, E. D. Stevens, N. M. Scott, and S. P. Nolan, J. Am. Chem. Soc., 2006, 128, 4101-4111. "Synthesis, Characterization and Isolation of Cationic Gold (I) N-Heterocyclic Carbene (NCH) Complexes," P. de Fremont, E. D. Stevens, M. R. Fructos, M. M. Diaz-Requejo, P. J. Perez, and S. P. Nolan, Chem. Comm. , 2006, 2045-2047. "Inclusion Complexes of Gossypol with 2-Pentanone, 3-Pentanone, and 2-Hexanone," M. K. Dowd and E. D. Stevens, J. Inclusion Phenomena Macrocyclic Chem., 2005, 51, 65-71. "An Experimental Charge Density Study of Mesulergine Hydrochloride, a Dopamine Agonist," N. Zhu, C. L. Klein Stevens, and E. D. Stevens, J. Chem. Cryst., 2005, 35, 13-22. "Determining the Crystal Structure of Cellulose IIII by Modeling," Z. M. Ford, E. D. Stevens, G. P. Johnson, and A. D. French, Carbohydrate Research, 2005, 340 827-833. "Double C-H Activation in a Rh-NHC Complex Leading to the Isolation of a 14-Electron Rh(III) Complex," R. Dorta, E. D. Stevens, and S. P. Nolan, J. Am. Chem. Soc 2004, 126, 5054-5055. "Stable, Three-Coordinate Ni(CO)2(NHC) Complexes Enabling the Determination of Ni-NHC Bond Energies," R. Dorta, E. D. Stevens, C. D. Hoff, and S. P. Nolan, J. Am. Chem. Soc., 2003, 125, 10490-10491. "Non-bonded Intra-molecular Interactions in 1,8-Disubstituted Naphthalenes with a Cyano Group as the Electrophillic Substituent," C. J. Crasto and E. D. Stevens, J. Molec. Struc.: Theochem, 2002, 582, 77-88. "C-H…X-R (X=Cl, Br, and I) Hydrogen Bonds Drive the Complexation Properties of a Nano-Scale Molecular Basket," C. L. D. Gibb, E. D. Stevens, and B. C. Gibb, J. Am. Chem. Soc., 2001, 123, 5849-5850. "A Wavefunction and Energy of the Azide Ion in Potassium Azide Obtained by a Quantum–Mechanically Constrained Fit to X-ray Diffraction Data." J. A. Snyder and E. D. Stevens, Chem. Phys. Lett. 1999, 313, 293-298.