Carbonyl complexes of iron, cobalt, and nickel with tris(trimethylsilylmethyl)phosphine

Abstract

Tris(trimethylsilylmethyl)phosphine (siphos) reacts with iron, cobalt, and nickel carbonyls under various conditions to give the series of new complexes, Fe(CO)3(siphos)2, Fe(CO)4(siphos), [Co(CO)3(siphos)2][Co(CO)4], [Co(CO)3(siphos)]2, and Ni(CO)3(siphos). The mercurials, Hg[Fe(CO)2(NO)(siphos)]2, Hg[Co(CO)4]2, and XHgCo(CO)3(siphos)(X = Cl and Br), and the thallium complex. Tl[Co(CO)3(siphos)]3, have also been prepared. Their structures are discussed on the basis of their i.r. and n.m.r. spectra. The cobalt–carbonyl complexes react with halogenated solvents to give the dimeric complex, [CoCl(CO)2(siphos)]2, which is the first dicarbonylmonophosphine complex of cobalt(I).