Comparative dft study of a ruthenium complex

Abstract

A comparative density functional theory (DFT) study of the Ruthenium complex (pentamethylcyclopentadienyl)(diisopropylmethylphosphine)(chloro)(trichlorosilyl)ruthenium hydride is reported. The molecule contains a ruthenium (Ru) atom, which, like other transition metals, is computationally difficult to handle due to the near degeneracy of their electronic states. Calculations were carried out in the gas phase using GAMESS software (the General Atomic and Molecular Electronic Structure System), which is an ab-initio quantum chemistry package. Five different basis sets were used, namely: Sapporo non-relativistic SPK DZP, SBKJ, 3-21G, STO3G, and STO6G. The molecule was optimized in quintuplicate with each of the basis sets. The computational results were compared with real X-ray data to assess how well the basis sets worked for a molecule containing a transition metal such as ruthenium. As the most computationally expensive basis set, the Sapporo non-relativistic SPK DZP was expected to give the most accurate results. However, unexpectedly, 3-21G, a computationally cheaper basis set, exhibited the best performance.