Synthesis, crystal structure, magnetic properties and EPR spectra of copper(II) acetate derivatives: tetra-(mu-acetato)bis(2-methylaminopyridine)copper(II) and catena-poly(aquadiacetato-mu-3-aminomethylpyridine)copper(II). Sheets formed by chains con

摘要

The derivatives of Cu(OAc)(2) (.) H2O with 2-methylaminopyridine and 3-aminomethylpyridine, [Cu-2(mu-OAc)(4)(MeNHpy)(2)] (1) and [Cu(OAc)(2)(mu-NH(2)CH(2)py)(H2O)](n) (2), respectively, have been synthesized and characterized. Compound 1 shows the dimer structure of [Cu-2(mu-OAc)(4)(H2O)(2)], with four syn-syn bridging acetate groups and the MeNHpy ligand coordinated in the axial positions. It is antiferromagnetic (2J = -285 cm(-1)). Signals of the triplet state are observed in its EPR spectrum and the zero-field splitting parameter has been calculated (D = 0.36 cm(-1); g(parallel to) = 2.35; g(perpendicular to) = 2.07). Otherwise, the ligand 3-aminomethylpyridine acts as bridging bidentate ligand in compound 2, forming infinite zig-zag chains. Each copper atom lies in a square-planar pyramidal coordination, determined by two nitrogen atoms of two bridge ligands, two oxygen atoms of two monodentate terminal acetate groups and a water molecule. The parallel chains form a sheet because of the hydrogen bonds between them. The shortest Cu-Cu distances are: 5.1270, 6.0952 and 6.2163 Angstrom (inter-chains) and 7.875 Angstrom (intra-chain). Compound 2 shows a slight antiferromagnetic effect below 30 K. The EPR spectra show an orthorhombic signal (g(1) = 2.26; g(2) = 2.08; g(3) = 2.06). (C) 2004 Elsevier B.V. All rights reserved.