Synthesis and spectroscopic characterisation of CpCoFe(2)(CO)(5)(mu(3)-Se)(2)(P-P) [P-P equals dppm or dppe]: Crystal structure of CpCoFe(2)(CO)(5)(mu(3)-Se)(2)(dppm)

The room temperature reactions of CpCoFe(2)(CO)(6)(mu(3)-Se)(2) (1) with bis(diphenylphosphino)methane and 1,2-bis(diphenylphosphino)ethane gave the phosphine derivatives of mixed-metal chalcogen clusters, CpCoFe(2)(CO)(5)(mu(3)-Se)(2)(PP)[PP = dppm (2), dppe (3)], respectively. Compounds 2 and 3 have been characterised by IR, and H-1, C-13, P-31 and Se-77 NMR spectroscopy and their compositions have been confirmed by elemental analysis. The structure of 2 has been elucidated by X-ray crystallography. Compound 2 crystallised in the monoclinic, space group P2(1)/n, with a = 20.705(5), b = 11.603(4), c = 32.528(9) Angstrom, beta = 107.38(2)degrees, V = 7108(4) Angstrom(3), Z = 8, D-c = 1.716 Mg m(-3) and R = 0.053 (Rw = 0.057). The structure consists of an Fe2CoSe2 metal core in which the dppm ligand bridges Co and one of the Fe atoms.