SYNTHESIS AND CRYSTAL-STRUCTURE OF [(CO)(6)FE-2(MU-SECH3)(2)]

The synthesis and crystal structure of (CO)(6)Fe-2(mu-SeMe)(2) (1) is reported. The dianion [Fe-2(CO)(6)(mu-SeMe)(2)](2-), obtained by the r eaction of Fe-2(CO)(6)(mu-Se-2) with (n)BuLi, reacted with iodomethane to give 1. Compound 1 has been characterised by IR, H-1 and C-13 NMR spectroscopy and elemental analysis. Its structure has been elucidated by X-ray crystallography. The compound belongs to the orthorhombic sp ace group PC2(1)n with a = 7.202(1), b = 10.544(1), c = 18.344(3) Angs trom, Z = 4. The structure was solved by direct methods and refined by full-matrix least-squares methods using NRCVAX programs, correcting f or extinction, to R = 0.067 and R(w) = 0.073 for 854 observed reflecti ons. The structure consists of an Fe2Se2 open butterfly core with each Fe atom containing three terminal carbonyl groups and each Se atom ha ving a CH3 group bonded to it at the equatorial sites.