Heterotrinuclear complexes containing a hexaselenolato-zinc(n), -cadmium(ii), -nickel(ii) or -iron(n) core

A series of linear trinuclear selenolate complexes of the general type [(OC)3Fe(μ-SePh)jM(μ-SePh)3Fe(CO)3] (M = Zn11 1. Cd11 2, Ni11 3 or Fe11 4) has been synthesized by reaction of the appropriate [M(H2O)n]2+ with the chelating metalloligand fac-[N(PPh3)2][Fe(CO)3(SePh)3] in acetonitrile. Their structures were elucidated on the basis of IR, UV/VIS, NMR spectra and X-ray crystallography. Compounds 1-4 are structurally related, each containing two tridentate metalloligands resulting in a MSe6 co-ordination environment of virtual Oh symmetry. Further reaction of 4 with 3 equivalents of 1, 10-phenanthroline (phen) initially afforded the intermediate [Fe(phen)3][Fe(CO)3(SePh)3]2 but eventually neutral [Fe(CO)2(phen)(SePh)2] 5 was formed as the sole product. Its crystal structure has been determined. This investigation shows thatyac-[Fe(CO)3(SePh)3]- serves as a tridentate chelating metalloligand and selenolate ligand-transfer reagent.