Polynuclear copper(II) carboxylates with 2,2′-bipyridine or 1,10-phenanthroline: Synthesis, characterization, X-ray structures and magnetism

[Cu-2(phen)(2)(mu-O2CH)(2)(O2CH)(2)](n) (1) and [Cu-6(bpy)(6)(mu-O2CC2H5)(7)(H2O)(2))](PF6)(5) center dot 2H(2)O (2) were synthesized and characterized by elemental analyses, electronic and EPR spectra and X-ray structure analyses. Compound 1 consists of four independent polymeric chains of dinuclear [Cu-2(phen)(2)(mu-O2CH)(2)(O2CH)(2)] subunits with the asymmetric bidentate bridging formato groups linking Cu atoms in an anti-anti configuration. All Cu(II) ions are in a distorted square-pyramidal geometry. The hexanuclear copper(II) molecule of compound 2 is constructed from three different dinuclear units connected to each other via two syn-anti-mu(3)-eta(1);eta(2) carboxylato bridges. All copper(II) ions are in the distorted square-pyramidal geometry. Two terminal dinuclear units are similar in structure in which both Cu(II) ions are doubly bridged by the syn-syn carboxylato anions, while those of the central dinuclear entity are triply bridged by two mu(3)-eta(1);eta(2) carboxylato anions via monoatomic bridging fashion and one syn-syn carboxylato anion. The magnetic susceptibility (5-350 K) of compound 2 was measured and agree with a weak anti-ferromagnetic interaction between the Cu(II) centers. (C) 2008 Elsevier B.V. All rights reserved.