Triphospha-ferrocenes as ligands: crystal and molecular structures of [Fe(η 5-C 5Me 5)(η 5-C 2Bu t2P 3)Cr(CO) 5] and of the noval nickel complex [Fe(η 5-C 5Me 5)(η 5-C 2Bu t2P 3)Ni(CO) 2] 2 containing two interlinked [Fe(η 5-C 5Me 5)(η 5-C 2Bu t2P 3)] systems

Abstract

The lone pair electrons of the two adjacent phosphorus atoms of the C 2Bu t 2P 3 ring in the triphospha0-ferrocene complex [Fe(η 5-C 5Me 5)(η 5-C 2Bu t 2P 3)] can ligate to other metal centres to afford novel bi- and tetrametallic complexes, whose structures have been elucidated by NMR and single-crystal X-ray studies. In the reaction of [Fe(η 5-C 5Me 5)(η 5-C 2Bu t 2P 3)] with Ni(CO) 4 the tetrametallic complex [Fe(η 5-C 5Me 5)(C 2Bu t 2P 3)Ni(CO) 2] 2 is formed. This complex is of particular interest because it represents the first example of the intermolecular interlinkage of two phospha-ferrocene units by two metal centres. A six-membered ring consisting of four phosphorus and two nickel atoms forms the core of the molecule and exhibits a boat configuration. The starting material [Fe(η 5-C 5Me 5)(η 5-C 2Bu t 2P 3)] reacts with Cr(CO) 5(thf), W(CO) 5(thf) and Fe 2(CO) 9 to yield the η 5-complexes [Fe(η 5-C 5Me 5)(η 5-C 2Bu t 2P 3)M(CO) n ] (M = Cr, W, n = 5; M = Fe, n = 4). Variable-temperature η 31P{ 1H} NMR studies reveal that these complexes are fluxional in solution.