SYNTHESIS AND X-RAY STRUCTURAL CHARACTERIZATION OF HETEROBIMETALLIC RHODIUM PLATINUM AND RHODIUM PALLADIUM BENZOTHIAZOLE-2-THIOLATE COMPOUNDS - THE 1ST BINUCLEAR COMPLEXES HAVING 2 SHORT-BITE ANIONIC BRIDGING LIGANDS IN A TRANS DISPOSITION

Reactions of the binuclear complex [Rh(mu-bzta)(CO)(PPh3)]2 (1) (bzta = benzothiazole-2-thiolate) with the complexes MCl2(cod) (M = Pd, Pt; cod = 1,5-cyclooctadiene) afford the new diamagnetic heterobinuclear compounds (Ph3P)M(mu-bzta)2RhCl(CO) [M = Pt (2), Pd (3)] as well as MCl2(PPh3)2 and [Rh(mu-Cl)(cod)]2 through a complicated process. The new mononuclear complexes trans-Pt(bzta)2(PPh3)2 and trans-PtH(bzta)(PPh3)2 react with [Rh(mu-Cl)(CO)2]2 to give (Ph3P)Pt(mu-bzta)2RhCl(CO) (2) in moderate or low yield. Characteristic features of the structures of compounds 2 and 3 are revealed by their IR and H-1 and P-31 NMR spectra. 2 crystallizes with a molecule of CH2Cl2 in the triclinic space group P1BAR with a = 11.425 (1) angstrom, b = 11.819 (1) angstrom, c = 14.393 (1) angstrom, alpha = 107.88 (1)-degrees, beta = 99.85 (1)-degrees, gamma = 93.43 (1)-degrees, V = 1809.3 (3) angstrom 3, and Z = 2. On the basis of 4546 independent observations and 332 parameters, the structure was refined to R = 0.0224 and R(w) = 0.0247. The metal centers, which are joined by a short metal-metal bond [2.6266 (4) angstrom], are bridged in a mutually trans and head-to-head fashion by the two benzothiazole-2-thiolate groups, which are bound to platinum through the exocyclic sulfur and to rhodium through the nitrogen. One triphenylphosphine on platinum, and chloro and carbonyl ligands on rhodium, complete the square planar and square pyramidal coordinations around the platinum and rhodium atoms, respectively.