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 isreported. The molecule contains a ruthenium (Ru) atom, which, like other transition metals, iscomputationally difficult to handle due to the near degeneracy of their electronic states. Calculations werecarried out in the gas phase using GAMESS software (the General Atomic and Molecular Electronic StructureSystem), 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 inquintuplicate with each of the basis sets. The computational results were compared with real X-ray data toassess how well the basis sets worked for a molecule containing a transition metal such as ruthenium. Asthe most computationally expensive basis set, the Sapporo non-relativistic SPK DZP was expected to givethe most accurate results. However, unexpectedly, 3-21G, a computationally cheaper basis set, exhibitedthe best performance.