Triphenylphosphine-substituted selenido and sulfido clusters of osmium derived from Ph3Pdouble bond; length as m-dashSe or Ph3Pdouble bond; length as m-dashS

Cleavage of Pdouble bond; length as m-dashSe bonds occurs readily in the room-temperature treatment of [Os3(CO)10(MeCN)2] with Ph3Pdouble bond; length as m-dashSe to give three new compounds, [Os3(μ3-Se)2(CO)8(PPh3)] (2), [Os3(μ3-Se)(μ3-CO)(CO)7(PPh3)2] (5) and [Os3(μ-OH)2(CO)8(PPh3)2] (6), respectively, and three known compounds, [Os3(μ3-Se)2(CO)9] (1), [Os3(μ3-Se)(μ-CO)2(CO)7(PPh3)] (3), and 1,2-[Os3(CO)10(PPh3)2] (4).No evidence for any product containing a co-ordinated Ph3Pdouble bond; length as m-dashSe ligand was obtained.The analogous reaction between [Os3(CO)10(MeCN)2] and Ph3Pdouble bond; length as m-dashS produces five new compounds [Os3(μ3-S)2(CO)8(PPh3)] (7), [Os3(μ3-S)(μ-CO)2(CO)7(PPh3)] (8), [Os3(μ3-S)(μ3- CO)(CO)7(PPh3)2] (9), [Os3(μ3-)2(CO)7(PPh3)2] (11) and compound 6 in addition to the known compound 4. Treatment of 2 with Me3NO at 50 °C gives the trinuclear cluster [Os3(μ3-Se)2(CO)7(PPh3)(NMe3)] (13) and the hexanuclear cluster [Os6(μ3-Se)4(CO)14(PPh3)2] (12). Treatment of compound 1 with PPh3 and Me3NO at room temperature gives [Os3(μ3-Se)2(CO)7(PPh3)2] (10). Compound 2 reacts with PPh3 similarly to give 10. Compound 3 reacts with elemental selenium at 110 °C to give 2. The new compounds 2, 5, 6 and 8 were characterized by single-crystal X-ray diffraction. The compounds 3, 5, 8 and 9 contain Os3(μ3-S) or Os3(μ3-Se)cluster cores with three metal–metal bonds while 2, 7, 10, 11 and 12 contain Os3(μ3-S)2or Os3(μ3-Se)2 cores two metal–metal bonds. The two hydroxy ligands in the triosmium cluster 6 bridging the open osmium-osmium edge and are probably derived from water. A study of the dynamic exchange of PPh3 ligands in 5 is also reported.