Conformational landscape of platinum(II)-tetraamine complexes: DFT and NBO studies

The potential energy surfaces of chiral tetraamine Pt(II) coordination complexes were computed at the B3LYP/LANL2DZ level of theory by a systematic variation of two dihedral angles: C12-C15-C34-C37 (θ) and C24-C17-C31-C48 (ψ) employing a grid resolution of 30°. Potential energy surfaces calculated using density functional theory methods and Boltzmann-derived populations revealed strong preference for one diasteromer of each series studied. In addition, natural bond orbital analysis show that the minima are stabilized predominantly by a combination of electronic interactions between two phenyl groups, the phenyl groups and the Pt ion, as well as with the amine groups. Additional experimental characterization of the diasteroisomers studied here is in progress and will permit further molecular modeling studies with the appropriate stereochemistry. © 2010 Springer Science+Business Media B.V.