The photochemical reactivity of triosmium cluster complexes containing 2-mercaptopyridine ligands: the crystal and molecular structures of the linked clusters [{Os 3H(CO) 10} 2(μ-SC 5H 3NCO 2)] and [{Os 3H(CO) 9} (μ-SC 5H 3NCO 2){Os 3H(CO) 10}]

• Published in: Journal of organometallic chemistry 1996-06, Vol.517 (1), p.173-181
• Main Authors: Ainscough, Eric W., Brodie, Andrew M., Coll, Richard K., Kotch, Thomas G., Lees, Alistair J., Mair, Angelika J.A., Waters, Joyce M.
• Format: Article
• Language: English
• Subjects: Crystal structure; Osmium cluster; Photochemistry; Thiolato
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/0022-328X(96)06186-4

The 2-mercaptopyridine triosmium cluster complexes, [{Os 3H(CO) 10} 2(μ-SC 5H 3NCO 2)], [Os 3H(CO) 10{SC 5H N(OH)}] and [Os 3H(CO) 10(SC 5H 4N)] upon exposure to irradiation at 366 nm undergo photochemical decarbonylation reactions in which the nitrogen of the mercaptopyridine ligand displaces a carbonyl on the third osmium of the thiolate-bridged triangle to yield [{Os 3H(CO) 10} 2(μ-SC 5H 3NCO 2)], [Os 3H(CO) 9{SC 5H 3N(OH)}] and [Os 3H(CO) 9(SC 5H 4N)]. The reactions proceed cleanly and quantum yields have been determined. The clusters have been characterised by spectroscopic means and the structures of [{Os 3H(CO) 10} 2 (μ-SC 5H 3NCO 2)] and [{Os 3H(CO) 9}(μ-SC 5H 3NCO 2){Os 3H(CO) 10}] established by single-crystal X-ray analyses. In both stru osmiums form two triangles, with the carboxylate bridging one edge of one triangle and the sulphur that of a second. For [{Os 3H(CO) 9}(μ-SC 5h 3NCO 2){Os 3H(CO) 10}] the nitrogen has displanced a carbonyl from the third somium o thiolate-bridged osmium triangle.