Iron, cobalt and vanadium complexes of the N(CH2CH2S)(3)(3-) ligand with chloride, azide, cyanide and carbonyl co-ligands

Reaction of [Fe(acac)(3)], Et4NCl and N(CH2CH2SH)(3) (NS3H3) in MeCN gave [ Et4N][FeCl(NS3)] 1 and metathesis the azide [Et4N][Fe(N-3)(NS3)] 2, but rea ction of [Fe(acac)(3)], R4NOAc and NS3H3 in MeCN gave [R4N][Fe-4(NS3)(3)] ( R=Et, 3; Me, 4). Complex 1 is reduced under various conditions giving R'[Fe (NS3)] (R'=Et4N, 5; Tl, 6; N2H5, 7) which probably contain sulfur-bridged [ {Fe(NS3)}(n)](n-) anions. Under CO, 1 is reduced to the paramagnetic [Et4N] [Fe(NS3)(CO)] 8 from which Tl[Fe(NS3)(CO)] 9 may be made by metathesis. Com pound 8 reacts with metal chlorides in acetonitrile giving trinuclear [M{Fe (NS3)(CO)}(2)-S,S'] (M=Fe, 10; Co, 11). The above complexes were characteri sed by microanalysis, IR and Mossbauer spectra and magnetic measurements; c rystal structure determinations were carried out on 1, 2, 8, 10, and 11. Th e properties of the anions of 1 and 8 and of the hypothetical anions [Fe(NS 3)](-) and [Fe(N-2)(NS3)](-) have been investigated by density functional t heory calculations. Compounds 8 and 10 have nu (CO) in the range 1960-1880 cm(-1) and model aspects of carbon monoxide binding to the cofactor of nitr ogenase. Related cyanide complexes [Et4N][M(NS3)(CN)] (M=Co, 12; V, 13) hav e been characterised, 12 by X-ray analysis.