A NEW LINKAGE ISOMER OF RHCL3(DMSO)(3) - PHOTOCHEMICAL-SYNTHESIS, CRYSTAL-STRUCTURE, AND REACTIVITY OF MER,TRANS-RHCL3(DMSO)(2)(DMSO)

The photochemical isomerization of mer,cis-RhCl3(DMSO)(2)(DMSO) (1) to the new linkage isomer mer,trans-RhCl3(DMS0)(2)(DMSO) (2) is describe d. The new isomer has been characterized by spectroscopic techniques a nd three-dimensional X-ray analysis. Crystal data: monoclinic, P2(1)/c , a = 10.123(6) Angstrom, b = 13.557(2) Angstrom, c = 11.109-(5) Angst rom, beta = 94.49(2)degrees, Z = 4, R = 0.048. This is the first case where the crystal structures of two DMSO linkage isomers are known. Co mplex 2 is thermodynamically unstable compared to 1, and in solution o f aprotic solvents it slowly isomerizes with first-order kinetics. The two isomers react stereospecifically with nitrogen ligands by followi ng different paths and produce isomeric products.