The reactivity of an iridaphosphirene complex, [Ir{C(But)P(Cy)}(CO)(PPh3)2], Cy = cyclohexyl, toward electrophiles

Abstract

The reactivity of an iridaphosphirene complex, [Ir{C(Bu^t)P(Cy)}(CO)(PPh₃)₂], Cy = cyclohexyl, toward a variety of electrophiles has been examined and in all cases reactivity occurs at the phosphorus centre within the three membered ring. Reaction with several protic reagents has led to the formation of the iridaphosphirenium salts, [Ir{C(Bu^t)P(H)(Cy)}(CO)(PPh₃)₂]X, X = BF₄⁻, CF₃SO₃⁻ or CF₃CO₂⁻, two of which have been crystallographically characterised. Though thermally stable in the solid state, in dichloromethane solutions these rearrange via 1,2-hydrogen migrations over seven days to give the Ir(I)–η¹-phosphaalkene complexes, [Ir(CO)(PPh₃)₂{η¹-P(Cy)C(H)(Bu^t)}]X, one of which (X = BF₄⁻) has been crystallographically characterised. The reactions of [Ir{C(Bu^t)P(Cy)}(CO)(PPh₃)₂] with MeI, S and Se have also been investigated and found to give the complexes, [Ir{C(Bu^t)P(Me)(Cy)}(CO)(PPh₃)₂]I and [Ir{C(Bu^t)P(E)(Cy)}(CO)(PPh₃)₂] E = S or Se, the former two of which have been structurally authenticated.