Triphenylphosphine-substituted selenido and sulfido clusters of osmium derived from Ph 3P [dbnd]Se or Ph 3P [dbnd

Abstract

Cleavage of P Se bonds occurs readily in the room-temperature treatment of [Os 3(CO) 10(MeCN) 2] with Ph 3P Se to give three new compounds, [Os 3(μ 3-Se) 2(CO) 8(PPh 3)] ( 2), [Os 3(μ 3-Se)(μ 3-CO)(CO) 7(PPh 3) 2] ( 5) and [Os 3(μ-OH) 2(CO) 8(PPh 3) 2] ( 6), respectively, and three known compounds, [Os 3(μ 3-Se) 2(CO) 9] ( 1), [Os 3(μ 3-Se)(μ-CO) 2(CO) 7(PPh 3)] ( 3), and 1,2-[Os 3(CO) 10(PPh 3) 2] ( 4).No evidence for any product containing a co-ordinated Ph 3P Se ligand was obtained.The analogous reaction between [Os 3(CO) 10(MeCN) 2] and Ph 3P S produces five new compounds [Os 3(μ 3-S) 2(CO) 8(PPh 3)] ( 7), [Os 3(μ 3-S)(μ-CO) 2(CO) 7(PPh 3)] ( 8), [Os 3(μ 3-S)(μ 3- CO)(CO) 7(PPh 3) 2] ( 9), [Os 3(μ 3-) 2(CO) 7(PPh 3) 2] ( 11) and compound 6 in addition to the known compound 4. Treatment of 2 with Me 3NO at 50 °C gives the trinuclear cluster [Os 3(μ 3-Se) 2(CO) 7(PPh 3)(NMe 3)] ( 13) and the hexanuclear cluster [Os 6(μ 3-Se) 4(CO) 14(PPh 3) 2] ( 12). Treatment of compound 1 with PPh 3 and Me 3NO at room temperature gives [Os 3(μ 3-Se) 2(CO) 7(PPh 3) 2] ( 10). Compound 2 reacts with PPh 3 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 Os 3(μ 3-S) or Os 3(μ 3-Se)cluster cores with three metal–metal bonds while 2, 7, 10, 11 and 12 contain Os 3(μ 3-S) 2or Os 3(μ 3-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 PPh 3 ligands in 5 is also reported.