Density functional study of structural properties and binding energies of dimethylsulfoxide Ru(II) complexes

The structures of a series of Ru(II)-dimethylsulfoxide complexes were optim ized using a density functional method. The obtained bond lengths reproduce the experimental trends quite well, although a general overestimate is fou nd. The theory is also used to predict the kind of coordination linkage (vi a O or S) preferred by dmso when different ancillary ligands are present. T he results are consistent with the experimental findings and can be explain ed in terms of sigma-pi contributions in the sulfoxide-metal bond. Insight into the strength of the oxygen/sulfur metal bonds is further given by the calculation of the binding energies of the sulfoxide fragments in different situations. Model molecules with emphasized electronic effects are also co nsidered to confirm the trends and to study special aspects such as preferr ed conformation structures. The general good performance, combined to compu tational economy, makes the present method suitable for further application s in this field. (C) 2000 Elsevier Science B.V. All rights reserved.