CONTROL OF THE SO2 COORDINATION MODE AT THE (MONOCHELATE)RHODIUM COMPLEX CLRH(P-SIMILAR-TO-O)(P-BOOLEAN-AND-O) WITH THE HEMILABILE LIGAND CY(2)PCH(2)CH(2)OCH(3)

The SO2 coordination mode at the rhodium complex [ClRh(P similar to O) (PO)] (1) [PO = eta(2)(O,P)-chelated Cy(2)PCH(2)CH(2)OCH(3) ligand; P similar to O = eta(1)(P)-coordinated] is controlled by the hemilabile ligand Cy(2)PCH(2)CH(2)OCH(3) and shows a dependence on the polarity o f the solvent. In polar organic solvents (e.g. acetone) the addition o f sulfur dioxide results in the formation of a trigonal-pyramidal orie nted SO2 group in [ClRh(eta(1)-SO2)(P similar to O)(PO)] (2a). However , in nonpolar media (e.g. n-hexane) a trigonal-coplanar geometry of th e SO2 unit in [ClRh(eta(1)-SO2)(P similar to O)(2)] (2b) is favored.