Synthesis and characterization of mononuclear nickel(II) and cobalt(II) complexes of 2,2,4,4-tetrakis(3,5-dimethylpyrazolyl)-6,6-diphenyl-2λ 5,4λ5,6λ 5-cyclotriphosphaza-1,3,5-triene L: Crystal structure of [niLCl2]

Abstract

Three complexes [NiLCl2] 2a, [NiLBr2] 2b and [CoLCl2] 2c, where L is the potentially multidentate ligand 2,2,4,4-tetrakis(3,5-dimethylpyrazolyl)-6,6-diphenyl-2λ 5,4λ5,6λ 5-cyclotriphosphaza-1,3,5-triene, have been prepared and characterized spectroscopically (IR, 1H and 31P NMR) and in the case of 2a, crystallographically. The NiII atom in 2a has been shown to exist in a distorted trigonal-bipyramidal geometry in which the halide atoms and a ring nitrogen atom define the equatorial plane; the axial positions are occupied by two nitrogen atoms derived from two pyrazolyl rings. Crystals of 2a are monoclinic with space group C2/c and unit cell dimensions: a = 38.190(8), b = 9.225(3), c = 21.830(4) Å, β = 108.29(2)° and Z = 8. The structure was refined to final R = 0.045 for 4414 observed data.