Reactivity of the unsaturated triosmium cluster [(μ-H)Os 3(CO) 8{Ph 2PCH 2P(Ph)C 6H 4}] with dithiols; X-ray structures of [Os 3(CO) 8(μ-SCH 2CH 2CH 2S)(Ph 2PCH 2PPh 2)]·1/2CH 2Cl 2 and [(μ-H)Os 3(CO) 7(μ 3-η 3-SCH 2CH 2CHS)(Ph 2PCH 2PPh 2)]·1/2H 2O

Abstract

Treatment of the unsaturated cluster [(μ-H)Os 3(CO) 8{Ph 2PCH 2P(Ph)C 6H 4}] ( 1) with HS(CH 2) n SH ( n=1, 1,2-ethanedithiol; n=2, 1,3-propanedithiol) lead to the novel compounds [(μ-H)Os 3(CO) 8{μ-S(CH 2) n S}{Ph 2PCH 2P(Ph)C 6H 4}] ( 9, n=2, 49%; 12, n=3, 56%) and [Os 3(CO) 8{μ-S(CH 2) n S} (μ-Ph 2PCH 2PPh 2)] ( 10, n=2, 20%; 13, n=3, 22%). The 52-electron compounds 9 and 12 contain a bridging hydride, a bridging dithiolato and an orthometallated dppm ligand while the 50-electron compounds 10 and 13 contain a doubly bridging dithiolato and a bridging dppm ligand. Compounds 9 and 12 are converted into 10 and 13 in 55 and 56% yields, respectively, by thermolysis at 110°C. Photolysis of 9 and 12 also gives 10 and 13 but in somewhat lower yields. Compounds 10 and 13 undergo decarbonylation and aliphatic C–H bond activation of the dithiolato moiety at 128°C to give [(μ-H)Os 3(CO) 7(μ 3-η 3-SCH 2CHS)(Ph 2PCH 2PPh 2] ( 11) and [(μ-H)Os 3(CO) 7(μ 3-η 3-SCH 2CH 2CHS)(Ph 2PCH 2PPh 2] ( 14) containing a bridging hydride, a triply bridging dithiolato and a bridging dppm ligand. Thermolysis of 9 and 12 at 128°C also gives 11 and 14 in 43 and 51% yields, respectively. Compounds 13 and 14 have been characterised by X-ray crystallography.