SYNTHETIC, SPECTROSCOPIC, AND STRUCTURAL STUDIES ON LANTHANIDE COMPLEXES OF DIPHOSPHAZANE DIOXIDE LIGANDS

Lanthanide nitrate complexes of diphosphazane dioxides Ph(2)P(O)N(Pr-i)P(O)Ph(2) (1) and (Pho)(2)P(O)N(Me)P(O)(OPh)(2) (2) have been synthesised and studied by conductometry, IR, multinuclear NMR spectroscopic methods and X-ray diffraction. Ligand 2 is accessible by two different methods, viz., by direct oxidation of the phosp(III)azane ligand or by starting from phosph(V)azane chloro precursor. The structure of 2 is confirmed by X-ray diffraction. Crystallographic data for 2: Triclinic, Space group P $($) over bar$$ 1, a = 10.078(1), b = 10.575(3), c = 12.364(4) Angstrom, alpha = 75.70(2)degrees, beta = 75.56(1)degrees, gamma = 77.68(1)degrees, Z = 2, V = 1220 Angstrom(3); structure refined to R(F) = 0.0459 On 3495 data with F > 3 sigma(F). The diphosphazane dioxide ligand exhibits trans geometry in the solid state. The structure of a lanthanide complex, [Pr(NO3)(3)(2)(2)] (14) is also determined by X-ray diffraction. Crystallographic data for 14: Trigonal, Space group P3(2), a = b = 15.710(2), c = 40.067(2) Angstrom, Z = 6, V = 8564 Angstrom(3); structure refined to R(F) = 0.0430 on 8077 data with F > 5 sigma(F). The two diphosphazane dioxide ligands and the nitrate groups are coordinated to praseodymium in a bidentate chelate fashion. The geometry around the ten coordinated metal is distorted bicapped square antiprism.