Unusual tridentate N3 capping coordination behavior of hexakis(3,5-dimethylpyrazolyl)cyclotriphosphazene, N3P3(3,5-Me2Pz)6: synthesis, spectroscopy, and electrochemistry of mono- and dinuclear copper(II) complexes and the x-ray structure of N3P3(3,5-Me2Pz)6.cntdot.CuCl2

Abstract

The reactions of hexakis(3,5-dimethylpyrazolyl)cyclotriphosphazene, N3P3(3,5-Me2Pz)6(HPCTP) (3), with copper-(II) halides afford mononuclear HPCTP·CuX2 (X = Cl, 3a; X = Br, 3b) and dinuclear HPCTP·2CuX2 (X = Cl, 3c; X = Br, 3d) coordination complexes. Optical absorption spectra and ESR spectra of these complexes suggest a distorted trigonal bipyramidal geometry around copper in all of the compounds 3a–3d. The structure of HPCTP·CuCl2 (3a) was determined by X-ray crystallography. The crystals of 3a are monoclinic, space group P21/n, with a = 21.338 (4) Å, b = 11.43 (3) Å, c = 18.285 (3) Å, β = 104.37 (2)o, V = 4321(2) Å3 and Z = 4. The structure shows that the cyclophosphazene ligand functions as an unprecedented N3 capping ligand: coordination to copper is through two nongeminal pyrazolyl pyridinic nitrogen atoms and one cyclophosphazene ring nitrogen atom, and the geometry around copper is distorted trigonal bipyramidal. Cyclic voltammetric studies have been carried out on complexes 3a–3d. © 1993, American Chemical Society. All rights reserved.