Ambidentate coordination of dimethyl sulfoxide in rhodium(III) complexes

Abstract

The two dimethyl sulfoxide solvated rhodium(III) compounds, [Rh(dmso-(kappa)O)5(dmso-(kappa)S)](CF3SO3)3 (1 & 1* at 298 K and 100 K, respectively) and [Rh(dmso-(kappa)O)3(dmso-(kappa)S)2Cl](CF3SO3)2 (2), crystallize with orthorhombic unit cells in the space group Pna21 (No. 33), Z = 4. In the [Rh(dmso)6]3+ complex with slightly distorted octahedral coordination geometry, the Rh–O bond distance is significantly longer with O trans to S, 2.143(6) Å (1) and 2.100(6) Å (1*), than the mean Rh–O bond distance with O trans to O, 2.019 Å (1) and 2.043 Å (1*). In the [RhCl(dmso)5]3+ complex, the mean Rh–O bond distance with O trans to S, 2.083 Å, is slightly longer than that for O trans to Cl, 2.067(4) Å , which is consistent with the trans influence DMSO-kS > Cl > DMSO-kO of the opposite ligands. Raman and IR absorption spectra were recorded and analyzed and a complete assignment of the vibrational bands was achieved with support by force field calculations. An increase in the Rh–O stretching vibrational frequency corresponded to a decreasing trans-influence from the opposite ligand. The Rh–O force constants obtained were correlated with the Rh–O bond lengths, also including previously obtained values for other M(dmso)6 3+ complexes with trivalent metal ions. An almost linear correlation was obtained for the MO stretching force constants vs. the reciprocal square of the MO bond lengths. The results show that the metal ion-oxygen bonding of dimethyl sulfoxide ligands is electrostatically dominated in those complexes and that the stretching force constants provide a useful measure of the relative trans-influence of the opposite ligands in hexa-coordinated Rh(III)-complexes

Keywords

Rhodium(III); dimethylsulfoxide; crystal structure; force constants

Published in

Dalton Transactions
2011, Volume: 40, number: 5, pages: 1111-1118
Publisher: The Royal Society of Chemistry

SLU Authors

• Torapava, Natallia

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Inorganic Chemistry


Publication identifier

DOI: https://doi.org/10.1039/c0dt01026j

Permanent link to this page (URI)

https://res.slu.se/id/publ/32978