Crystal and molecular structures of dppm-bridged diiron dithiolate complexes [Fe2(CO)4(μ-SAr)2(μ-dppm)] (Ar=Ph, p-tol; Ar2=CN–p-tol)

Crystallographic studies have been carried out on three bis(diphenylphosphino)methane (dppm) bridged diiron dithiolate complexes. Both [Fe2(CO)4(μ-SAr)2(μ-dppm)] (Ar=Ph, p-tol) adopt the expected anti configuration, while [Fe2(CO)4{μ-SC(N–p-tol)S}(μ-dppm)] is constrained to be syn. In each the diphosphine lies trans to one of the bridging sulfurs but this has no significant effect on the iron–sulfur bond lengths.