SYNTHESIS, SPECTROSCOPY, AND ELECTROCHEMISTRY OF TERNARY COPPER(II) COMPLEXES WITH TETRAKIS(3,5-DIMETHYLPYRAZOLYL)CYCLOTRIPHOSPHAZENE AND NITROGENOUS BASES - X-RAY STRUCTURES OF N(3)P(3)PH(2)(3,5-ME(2)PZ)(4).CU(CLO4)(2).2H2O AND N(3)P(3)PH(2)(3,5-ME(2)PZ)(4).CU(CLO4)(2).2IMH

The reaction of tetrakis(3,5-dimethylpyrazolyl)cyclotriphosphazene N(3 )P(3)Ph(2)(3,5-Me(2)Pz)(4) (TPCTP), with copper(II) perchlorate hexahy drate affords a mononuclear coordination complex, TPCTP.Cu(ClO4)(2).2H (2)O (1). Tnis, on treatment with nitrogenous bases such as pyridine, imidazole, 2,2'-bipyridine, and 1,l0-phenanthroline in appropriate pro portions, yields the ternary complexes TPCTP.Cu(ClO4)(2).nL (2,L = Py (n = 2); 3, L = ImH (n = 2); 4, L = Bipy (n = 1); 5, L = Phen (n = 1)) . Optical absorption and EPR spectra of these complexes indicate a dis torted tetragonal geometry around copper in all the compounds. The str uctures of TPCTP.Cu(ClO4)(2).2H(2)O (1) and TPCTP.Cu(ClO4)(2).2ImH (3) were determined by X-ray crystallography. Crystals of 1 were monoclin ic, with the space group P2(1)/a and with a = 18.401(4) Angstrom, b = 19.927(4) Angstrom, c = 11.875(20) Angstrom, beta = 90.696(15)degrees, V = 4354(15) Angstrom(3), and Z = 4. The copper atom is coordinated b y two nongeminal pyrazolyl pyridinic nitrogens, two water molecules, c yclophosphazene skeletal nitrogen, and a perchlorate anion in an elong ated octahedral geometry. Crystals of compound 3 were also monoclinic, with the space group P2(1)/n and with a = 12.121(7) Angstrom, b = 21. 110(2) Angstrom, c = 19.464(5) Angstrom, beta = 101.39(3)degrees, V = 4882(3) Angstrom(3), and Z = 4. Copper assumes a distorted square pyra midal geometry with the basal plane comprised of two pyrazolyl nitroge ns and two imidazolyl nitrogens and the apical position being occupied by the cyclophosphazene ring nitrogen. The cyclophosphazene ring nitr ogen-copper binding appears to be a sigma-bonding interaction, as evid enced by the lengthening of the P-N bonds that flank the coordination site. Cyclic voltammetric studies have also been carried out on comple xes 1-5. The six-coordinate complex 1 exhibits redox potentials 0.3 V higher than the fivecoordinate square pyramidal complexes.