Mixed metal pentanuclear clusters [MFe4S4(CO)12]z- (M = V, Mn and Cr; z=0, 2) and X-ray crystal structures of [VFe4S4(CO)12] and [MnFe4S4(CO)12]2-

Reaction of VCL3, MnCl2 and CrCl3+Zn with [Fe2S2(CO)(6)](2-), from reduction of [Fe2S2(CO)(6)] by LiEt3BH, resulting in pentanuclear mixed metal clusters [VFe4S4(CO)(12)] (1), [Et4N](2)[MnFe4S4(CO)(12)] (2) and [Et4N]2[CrFe4S4(CO)(12)] (3), respectively. Complexes 1, 2 and 3 have been characterized by elemental analysis, spectroscopy and the crystal structures of I and 2 have been determined by X-ray crystallography. The structures of 1 and 2 contain a penta-nuclear M-Fe-S core, [Fe2S2MS2Fe2](z-) (M = V, z = 0 (1) and M = Mn, z = 2 (2)), consisting of two [Fe2S2]-units chelating to a metal atom. The two [Fe2S2] units are in 'butterfly' type configuration like the one in [Fe2S2(CO)(6)](2-). In 1 there are four V-Fe bonds of 2.822-2.865 Angstrom, but in 2 there were no Mn-Fe bonds found. V-S distances are 2.205-2.210 Angstrom and Mn-S bond lengths are 2.358-2.380 Angstrom. The novel structural configuration, IR spectra and synthesis were discussed. (C) 2003 Elsevier B.V. All rights reserved.