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

The derivatives of Cu(OAc)2 · H2O with 2-methylaminopyridine and 3-aminomethylpyridine, [Cu2(μ-OAc)4(MeNHpy)2] (1) and [Cu(OAc)2(μ-NH2CH2py)(H2O)]n (2), respectively, have been synthesized and characterized. Compound 1 shows the dimer structure of [Cu2(μ-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∥=2.35; g⊥=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 Å (inter-chains) and 7.875 Å (intra-chain). Compound 2 shows a slight antiferromagnetic effect below 30 K. The EPR spectra show an orthorhombic signal (g1=2.26; g2=2.08; g3=2.06).