CRYSTAL STRUCTURE OF Fe-S CLUSTER COMPLEX (mu-MeS) [mu-Fe(CO)(2)CpS] Fe-2(CO)(6)

The influences of the different substituents R-1 and R-2 on the structures of (mu-(RS)-S-1)(mu-(RS)-S-2)Fe-2(CO)(6) cluster complexes were studies. The [-Fe-3(CO)(2)Cp] is a novel substituent, and thus there are some characteristics in the complex. The title complex belongs to monoclinic system, space group P2(1)/n. The unit cell parameters a = 7.3099(7), b = 10.774(1), c = 22.531(4) angstrom, gamma = 92.91(1)degrees, z = 4, and D-oalo. = 1.856 g cm(-3). Refinement converged at R = 0.024 and R-w = 0.030 for the 2110 reflections with I >= 3 sigma(I). The Fe-S-(2) bond length are longer than the Fe-S-(1) bond length, and the S-(2) atom is bonded with the larger substituent Fe(CO)(2)Cp. The unequivalency of the Fe-S bonds in the S bridges relates to the diffrentia between R-1 and R-2. The average length of Fe-S bonds is increased, when the Fe or S atom is bonded with a large substituent, like PPhs or Fe(CO)(2)Cp. Besides, the torsion angle of the cluster skeleton is sensitive to the existence of the large substituent. The Fe-S bond distances inside the cluster skeleton are shorter than that outside the cluster skeleton. It is thus obvious that the Fe-Fe bond has the effect of stability the skeleton. The conformation of the substituents is (a,e) type. This is favourable for decreasing the repelling effect between the substituents.