Lanthanide nitrate complexes with triethylphosphine oxide. Solid state and solution properties

作者：Bowden Allen; Singh Kuldip; Platt Andrew W G^*

来源：Polyhedron, 2012, 42(1): 30-35.

DOI：10.1016/j.poly.2012.04.021

• Lanthanide nitrate complex
• Phosphine oxide
• X-ray structure
• Variable temperature NMR

Complexes between lanthanide nitrates and triethylphosphine oxide have been prepared and fall into two distinct categories. With the lighter lanthanides Ln(NO3)(3)(Et3PO)(3) (Ln = La, Ce, Pr, Nd, Eu) are formed whilst for the heavier metals mixtures of Ln(NO3)(3)(Et3PO)(3) and Ln(NO3)(3)(Et3PO)(2) are isolated. The structures of Ln(NO3)(3)(Et3PO)(3) (Ln = La, Ce, Eu) have been determined by single crystal X-ray crystallography and show that all the complexes are 9-coordinate and have a pseudo met-octahedral arrangement if the bidentate nitrates are envisaged as monodentate ligands. The conductivity in dichloromethane and acetonitrile indicates that the complexes are non-conducting. NMR spectra in CD2Cl2 solution are consistent with a rapid interconversions of the inequivalent phosphorus environments. For the Yb and Lu complexes static structures can be assigned to peaks in the low temperature P-31 NMR spectra which also show evidence of a pseudo fac-isomer and a 1:2 complex. The formation of mixtures of 1:2 and 1:3 complexes for the heavier lanthanides is discussed in terms of the balance between steric effects and the basicity of the phosphine oxide ligands.

• 出版日期2012-7-25