Reactivity of [Fe-2(CO)(6)(mu-CO)(mu-dppm)] towards unsaturated sulfur-containing compounds, SO2, CS2 and ArNCS: facile carbon-sulfur bond cleavage at the diiron centre

Photolysis of [Fe-2(CO)(6)(mu-CO)(mu-dppm)] (1) with SO2, CS2 and ArNCS lea ds to the formation of [Fe-2(CO)(6)(mu-SO2)(mu-dppm)] (2), [Fe-4(CO)(10)(mu (3)-S)(mu-CS)(mu-dppm)(2)] (3), [Fe-2(CO)(3)(CNAr){mu-SC(NAr)C(O)S}(mu-dppm )] (4-5) and [Fe-2(CO)(4){mu-SC(N-p-tolyl)C(O)S}(mu-dppm)] (6), respectivel y. Complex 2 is a simple CO substitution product, white in 3 carbon-sulfur cleavage and coupling of diiron units has occurred. Dithiolate-bridged 4-6 also result from carbon-sulfur bond cleavage of one isothiocyanate and coup ling of the sulfur with CO and a second isothiocyanate. Two isomers of comp lexes 3-6 are found and in thiolate-bridged 4-6 these interconvert as a res ult of inversion at the imine nitrogen, which has been monitored by VT NMR. (C) 2000 Elsevier Science S.A. All rights reserved.