Synthesis, structure, and magnetic properties of two new copper(II) complexes with pseudohalide ligands.: A dimer [Cu2(μ1,1-NCO)2(NCO)2(phen)2] with NCO bridge and ferromagnetic coupling and a mononuclear {[Cu(meso-cth)(CN)]ClO•4H2O}2 with two independent [Cu(meso-cth)(CN)] units peudo-related by a symmetry center

Two new copper(II) complexes with pseudohalide ligands have been synthesized and their crystal structures have been determined by X-ray diffraction: a dinuclear complex [Cu-2(mu (1.1) -NCO)(2)(NCO)(2)(phen)(2)] (1) in which two cyanate ligands form an end-on bridge between the two copper(II) atoms and the two other act as terminal ligands, and a mononuclear complex {[Cu(meso-cth)(CN)]ClO4.H2O}(2) (2) with two independents [Cu(meso-cth)(CN)] units pseudorelated by a symmetric center, were phen is 1,10-phenantroline and meso-cth is 5,5,7,12,12,14-hexamethyl-1,4,8,11 -tetraazacyclo-tetradecane. Magnetic susceptibility data, measured from 2 to 300 K, show ferromagnetic coupling for the dinuclear complex 1. These data were fitted to an equation derived from the Hamiltonian H= - JS(1)S(2), given the parameters J= + 13.75 cm(-1), g = 2.17. Complex 2 shows Curie law behavior (theta = 0). (C) 2001 Elsevier Science B.V. All rights reserved.