resumo
A series of new M[(dcbdt)(2)](-z) complexes of the dicyanobenzodithiolate (dcbdt) ligand with a range of transition metals (M = Co, Pd, Pt, Cu, Au and Zn) in different oxidation states (z = 0.4, 1, 2) were prepared as their nBu(4)N salts and characterised by X-ray diffraction, cyclic voltammetry, EPR and static magnetic susceptibility. Their properties are discussed in comparison with the Ni and Fe analogues described by us recently. The structures of these complexes belong to four distinct groups: i) the Zn-II compound 10 is triclinic P (1) over bar with the metal in a tetrahedral coordination geometry; ii) other M-II complexes [M = Pt (8), Pd (7), Co (3) and Cu (5)] are monoclinic C2/m, and are isostructural with the Ni-II analogue, presenting a perfectly planar square geometry; iii) the Co-III compound 4 is triclinic P (1) over bar, and isostructural with the Fe and Ni analogues, with a strong dimerisation of the M(dcbdt)(2) units and the metal in a square-pyramidal coordination geometry; iv) the M-III, salts with M = Au (2), Cu (6) and Pt (9) are monoclinic P2(1)/c and the complexes are arranged as pseudodimers. The EPR and static magnetic-susceptibility measurements show that the Co-II (3), Cu-II (5), Pt-III (9) and Co-III (4) complexes are paramagnetic corresponding to an S = 1/2 state, except for Co-III, which is in a high-spin S = 1 configuration. The solid state EPR spectra of the Co-II compound presents a hyperfine structure typical of the I = 7/2 Co-59. The temperature dependence of the paramagnetic susceptibility of the Pt-III compound follows a singlet-triplet model with a dimer antiferromagnetic coupling, J, of 984 K. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
palavras-chave
CRYSTAL-STRUCTURE; PHYSICAL-PROPERTIES; NICKEL; OXYGEN; SALTS
categoria
Chemistry
autores
Alves, H; Simao, D; Santos, IC; Gama, V; Henriques, RT; Novais, H; Almeida, M
nossos autores
