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The preparation of four new copper(II) complexes with different N-donor ligands [CuBr(2-benzylpyridine)] ( 1), [CuBr(2-benzylpyridine)(2,2′-bipyridine)]·HO ( 2), [CuBr(3-methyl-2-phenylpiridine)] ( 3), [Cu(picolinate)]·KI ( 4) from copper(I) halides as starting material is described. During the preparation of compound 4 a ligand oxidation reaction took place to give the picolinate ligand starting from 2-(2-methylaminoethyl)pyridine. The complexes were characterized by elemental analyses, IR spectroscopy and crystallographic studies. Single crystal X-ray diffraction analysis of the complexes reveals their monomeric penta- and tetracoordinated nature. For all compounds, the copper(II) present a common square planar coordination except for compound 2 which is five coordinated in a quasi-square pyramidal configuration with τ of 0.29. The Cu-N distances for these compounds are in the range of 1.959(4)-2.041(3) Å, Cu-O distance was 1.961(3) Å and Cu-Br distances were in the range of 2.4052(4)-2.4381(6) Å for the square base configuration while for apical distance it was 2.6745(7) Å. Magnetic properties have been investigated for all compounds in the temperature range 2-300 K. Compound 1 shows weak antiferromagnetic intermolecular interaction. [ABSTRACT FROM AUTHOR]

The synthesis and structural characterization of new six Cu(ii) coordination polymers of formulae {[Cu2(ctc-cbut)(H2O)4]·2(H2O)}n (1), {[Cu5(ctc-cbut)2(OH)2(H2O)8]·7(H2O)}n (2), {[Cu2(ctc-Hcbut)(OH)(H2O)2]·4(H2O)}n (3), [Cu2(ttt-cbut)(H2O)4]n (4), {[Cu2(ttt-cbut)(H2O)4]·4(H2O)}n (5) and {[Cu4(ttt-cbut)2(H2O)2]·3(H2O)}n (6) (ctc-H4cbut = cis,trans,cis-1,2,3,4-cyclobutanetetracarboxylic acid and ttt-H4cbut = trans,trans,trans-1,2,3,4-cyclobutanetetracarboxylic acid), have been carried out, together with a computational study of the electronic and thermal free energies of the four isomers of the given ligand. The compounds 1–3 exhibit the ligand in its commercial cis,trans,cis conformation while 4–6 were synthesized with the trans,trans,trans isomer, after thermal treatment of the ctc-isomer. The topology of the six complexes synthesized have differences in dimensionality: compound 4 shows a one-dimensional topology, compound 3 presents a 2D-topology with a three nodal 4,4,4-c network, while 1, 2, 5 and 6 exhibit a 3D-topology with a binodal network 3,6-c for 1 and [412·612·84] [46]-flu for 2. Compound 5 presents a triply interpenetrated [66]-dia network while 6 exhibits a three-nodal network with [43][44·62][47·610·84] point symbol. [ABSTRACT FROM AUTHOR]