Lanthanide nitrate complexes of diphenylmethylphosphine oxide: synthesis and spectroscopic studies. Crystal structures of [La(Ph 2MePO) 3(NO 3) 3], [La(Ph 2MePO) 4(NO 3) 3]· xMe 2CO and [Yb(Ph 2MePO) 4(NO 3) 2]PF 6

Abstract

The reaction of Ln(NO 3) 3·6H 2O (Ln=lanthanide except Pm) with Ph 2MePO in a 1:3 or 1:4 ratio in acetone or ethanol produces [Ln(Ph 2MePO) 3(NO 3) 3] which have been characterised by analysis, IR, 1H and 31P{ 1H} NMR spectroscopy and conductance measurements. The [Ln′(Ph 2MePO) 3(NO 3) 3] (Ln′=Pr–Tb) exist only as tris complexes in solution and are unaffected by the presence of excess Ph 2MePO. In contrast the [Ln″(Ph 2MePO) 3(NO 3) 3] (Ln″=Ho–Lu) partially decompose in CH 2Cl 2 solution into [Ln″(Ph 2MePO) 4(NO 3) 2] +, and [Ln″(Ph 2MePO) 4(NO 3) 2]PF 6 are readily isolated from Ln″(NO 3) 3, Ph 2MePO and NH 4PF 6 in acetone. For lanthanum only, a neutral 1:4 complex [La(Ph 2MePO) 4(NO 3) 3] was isolated. X-ray crystal structures show that [La(Ph 2MePO) 3(NO 3) 3] contains nine-coordinate La, whilst [La(Ph 2MePO) 4(NO 3) 3]· xMe 2CO contains a ten-coordinate metal centre. The structure of [Yb(Ph 2MePO) 4(NO 3) 2]PF 6 reveals an eight-coordinate cation and all complexes contain bidentate nitrato-groups.