Reactivity of [(μ-H)Os 3(CO) 8{Ph 2PCH 2P(Ph)C 6H 4}] with organic heterothiols; X-ray structures of [H(μ-H)Os 3(CO) 8(η 2-pyS){Ph 2PCH 2P(Ph)C 6H 4}] and [Os 3(CO) 8(μ-η 2-pyS){Ph 2PCH 2P(Ph)C 6H 4}

Abstract

The reaction of [(μ-H)Os 3(CO) 8{Ph 2PCH 2P(Ph)C 6H 4}] ( 3) with pyridine-2-thiol (pySH, C 5H 4NSH) at room temperature gave two novel clusters [(μ-H)Os 3(CO) 8(μ-pyS)(μ-dppm)] ( 4) and [H(μ-H)Os 3(CO) 8(η 2-pyS){Ph 2PCH 2P(Ph)C 6H 4}] ( 5) in 55 and 15% yields, respectively. Compound 4 is formed by simple oxidative addition of pySH and demetallation of the phenyl ring of dppm ligand whereas the 50-electron cluster 5 results from oxidative addition of pySH and coordination of the thiolate moiety as a chelating ligand and cleavage of one of the metalmetal bonds. The analogous reaction of 3 with pySH at 80°C gave the new compound [Os 3(CO) 8(μ-η 2-pyS){Ph 2PCH 2P(Ph)C 6H 4}] ( 6) in 20% yield together with 4 and 5 in 40 and 7% yields, respectively. Compound 6 contains a chelating/bridging pyS ligand and an orthometallated dppm ligand. In contrast, the reaction of 3 with pyrimidine-2-thiol (pymSH, C 4H 3N 2SH) at room temperature and at 80°C affords only the simple oxidative addition product [(μ-H)Os 3(CO) 8(μ-pymS)(μ-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%) with the formation of 3 (10%) by refluxing in heptane at 98°C. The new complexes 4, 5, 6 and 7 have been characterized by spectroscopic data together with X-ray structure determinations for 5 and 6.