[Fe4s4i2(C6h10(Nhcsnhme)2)] - A Neutral Iron-Sulfur Cluster With A Bidentate Ligand

The reaction of [Fe4S4I2(SC(NMe2)2)2] with racemic trans-1,2-bis(3-methylthioureido)-cyclohexane in tetrahydrofuran (thf)yields[Fe4S4I2(C6H10(NHCSNHMe)2)].4thf(2). 2 crystallizes in the monoclinic space group C2/c with a = 1471.7(2), b = 1329.7(2), c = 2339.3(3) pm, beta = 107.70(1), V = 4362.3 x 10(6) pm3, Z = 4, R = 0.057. The cluster exhibits C2 symmetry in the solid state. The replacement of the monodentate neutral ligands results in a cluster in which the bifunctional thiourea derivative bridges two different iron sites of the slightly compressed [Fe4S4] core. The most striking feature are the differences of the Fe-Fe distances which are 269.8 pm between thiourea coordinated atoms and 280.7 pm between Fe atoms with iodide ligation. The Fe-S thiourea distance was found to be 229.3 pm.