AN UNSYMMETRICAL LIGAND ARRANGEMENT IN THE COMPLEX RE-2(MU-MP)(4)CL-2(MP=MONOANION OF 2-MERCAPTOPYRIDINE)

The syntheses, structures, and properties of the dirhenium(III) comple xes Re-2(mu-mp)(4)X(2) (mp monoanion of 2-mercaptopyridine; X = Cl, Br ) are described. These complexes can be prepared by the reactions of ( n-Bu(4)N)(2)Re(2)X(8) or cis-Re-2(O-2-CCH3)(2)X(4)(H(2)O2) (X = Cl, Pr ) with 2-mercaptopyridine. They have a surprising structure in which t here is an unsymmetrical 3:1 orientation of bridging mercaptopyridinat o ligands; this contrasts with analogous complexes derived from 2-hydr oxypyridine in which the more symmetrical stereoisomer with a cis 2:2 head-to-tail arrangement of mu-hp ligands is present. [GRAPHICS] CS]