Thomas P. Fehlner

Office: (219)631-7243 FAX: (219)631-6652
E-Mail: thomas.p.fehlner.1@nd.edu

INORGANOMETALLIC CHEMISTRY

To a large extent, inorganic chemistry consists in the study of species that exhibit complex structures, "unnatural" properties and unusual reactivity. The development of inorganic chemistry over the last 50 years has generated new models for chemical bonding and new ideas of chemical reaction mechanisms. The cross fertilization between organic chemistry and transition metal chemistry has resulted in the active field of organometallic chemistry--the chemistry of the metal-carbon bond. A large part of our own efforts are focused on the preparation and characterization of new compounds containing direct, unsupported bonds between transition metals and main group atoms particularly boron, i.e., one area of inorganometallic chemistry. Characterization takes the form of geometric structure determination (X-ray diffraction), spectroscopic characterization (mass spectrometry, nmr spectrometry, infra-red spectrometry), analysis of bonding (molecular orbital quantum chemical calculations) and characterization of reactivity (final product distribution and kinetic and mechanistic studies on selected systems). In addition, these new compounds are being used as molecular precursors for the preparation of novel materials. The latter area involves synthesis and the utilization of a variety of spectroscopic techniques for the characterization of the materials. The development of coordinated clusters (Figure 1) as precursors for chemical catalysis is underway in a

Figure 1

collaboration with Prof. Wolf in Chemical Engineering. Our strategy is outlined in Figure 2. The resultant porous, active solids exhibit activities and selectivities towards the hydrogenation of organic substrates that is unique and suggests that the method constitutes a new approach to the preparation of heterogeneous catalysts.

Figure 2

Selected Publications:

"Synthesis of Cobaltaborane Clusters from [Cp*CoCl]2 and Monoboranes. New Structures and Mechanistic Implications", Y. Nishihara, K. J. Deck, M. Shang, T. P. Fehlner, B. S. Haggerty, and A. L. Rheingold, Organometallics, 13, 4510 (1994).

"Activity and Characterization of Self-Supported Model Catalysts Derived from Cobalt- Based Clusters of Clusters. Hydrogenation of 1,3-Butadiene", M. A. Banares,, L. Dauphin, V. Calvo-Perez, T. P. Fehlner, and E. E. Wolf, J. Catalysis, 152, 396 (1995).

"Effect of Precursor Core Structure on the Hydrogenation of 1,3-Butadiene Catalyzed by Cluster-Derived Model Catalysts", M. A. Banares, L. Dauphin, X. Lei, W. Cen, M. Shang, E. E. Wolf and T. P. Fehlner, Chem. Mater, 7, 553 (1995)

"Preparation and Characterization of Cobaltaboranes Containing Cobalt Carbonyl Fragments", C.-S. Jun, J.-F. Halet, A. L. Rheingold and T. P. Fehlner, Inorg. Chem., 34, 2101 (1995).