Electronic structural investigations of bi- and polymetallic complexes using quantum mechanical methods

Understanding the dynamics influencing chemical reactivity is essential for properly exploiting matter into more useful purposes. In that manner, computational chemistry is a tool frequently used to study chemical properties at the most intimate level, i.e. the single molecule. With this work, we probe the chemistry governing a variety of multi-faceted bi- and polymetallic compounds. To date our research consists of four major projects: bimetallic rhodium-catalyzed hydroformylation and aldehyde-water shift hydrocarboxylation catalysis; a novel linear M-H-M interaction in a bridged bis(dialkylphosphino)methane complex of nickel; and CeBe13, a heavy fermion conductor. Computational investigations on these systems allow us to study specific chemical phenomena theoretically at the molecular level. The Gaussian 98 system of programs has been utilized to study these systems. The computational approach used to study these varied according to investigative need. For all but the solid-state system, CeBe13, density functional theory was generally used to study molecular properties. For most species, the molecular geometry was optimized to the ground state. Afterward, a Mulliken population analysis was used to evaluate molecular bonding. Within the catalytic studies, vibrational analyses were completed and comparisons of calculated frequencies with experimental infrared data were made. Comparisons of the ground-state geometries with complementary crystal structures serves as a good indicator of the general accuracy of these types of calculations on systems of interest to us. A formal description of the computational method used with each system of interest is discussed as well as their results and implications