Reactivity of [(mu-H)Os-3(CO)(8) {Ph2PCH2P(Ph)C6H4}] with organic heterothiols; X-ray structures of [H(mu-H)Os-3(CO)(8)(eta(2)-pyS){Ph2PCH2P(Ph)C6H4}] and [Os-3(CO)(8)(mu-eta(2)-pyS){Ph2PCH2P(Ph)C6H4}]

The reaction of [(mu -H)Os-3(CO)(8){Ph2PCH2P(Ph)C6H4}] (3) with pyridine-2- thiol (pySH, C5H4NSH) at room temperature gave two novel clusters [(mu -H)O s-3(CO)(8)(mu -pyS)(mu -dppm)] (4) and [H(mu -H)Os-3(CO)(8)(eta (2)-pyS){Ph 2PCH2P(Ph)C6H4}] (5) in 55 and 15% yields, respectively. Compound 4 is form ed by simple oxidative addition of pySH and demetallation of the phenyl rin g of dppm ligand whereas the 50-electron cluster 5 results from oxidative a ddition of pySH and coordination of the thiolate moiety as a chelating liga nd and cleavage of one of the metal-metal bonds. The analogous reaction of 3 with pySH at 80 degreesC gave the new compound [Os-3(CO)(8)(mu-eta (2)-py S){Ph2PCH2P(Ph)C6H4}] (6) in 20% yield together with 4 and 5 in 40 and 7% y ields, respectively. Compound 6 contains a chelating/bridging pyS ligand an d an orthometallated dppm ligand. In contrast, the reaction of 3 with pyrim idine-2-thiol (pymSH, C4H3N2SH) at room temperature and at 80 degreesC affo rds only the simple oxidative addition product [(mu -H)Os-3(Co)(8)(mu -pymS )(mu -dppm)] (7). Compound 6 reacts with molecular hydrogen to give 5 and 4 in 20 and 10% yields, respectively. Compound 5 was converted to 6 (30%) wi th the formation of 3 (10%) by refluxing in heptane at 98 degreesC. The new complexes 4, 5, 6 and 7 have been characterized by spectroscopic data toge ther with X-ray structure determinations for 5 and 6. (C) 2000 Published by Elsevier Science B.V. All rights reserved.