Di-mu-halo-bis{[tris(2-pyridylmethyl)amine-kappa N-4]nickel(II)} bis(triethylammonium) tetraperchlorate: Magnetostructural studies

[{Ni(TPA)Br}(2)](Clo(4))(2).2HNEt(3)ClO(4), where TPA is tris-(2-pyridylmet hyl)amine, crystallizes in the monoclinic space group P2(1)/c with Z = 2, a = 11.531(3) Angstrom, b = 22.141(3) Angstrom, c = 12.511(2) Angstrom and b eta = 107.44(1)degrees. The structure was determined at ambient temperature from 5519 reflections (2937 observed) with R = 0.0426 and R-w = 0.0404. Th e [{Ni(TPA)Br}(2)](2+) core is centrosymmetric with unsymmetrical bridges ( Ni-Br=2.504(1) and 2.662(1) Angstrom). Each Ni atom is pseudo-octahedral si x-coordinate. Triethylammonium perchlorate cocrystallizes with the metal co mplex. Magnetic susceptibility studies (fit to the Ginsberg model) indicate the Ni centers are ferromagnetically coupled with J/k = 10.0(5) cm(-1). Th e chloro complex ([{Ni(TPA)Cl}(2)](Clo(4))(2).2HNEt(3)ClO(4)) is also ferro magnetically coupled with J/k = 7.6(1) cm(-1). (C) 2000 Elsevier Science S. A. All rights reserved.