Synthesis, spectroscopic and structural characterization of some novel adducts of copper(II) salts with unidentate nitrogen bases

Syntheses, spectroscopic characterization and single crystal X-ray studies are reported for a number of complexes of copper(II) salts with simple monodentate nitrogen bases. The 1: 4 adduct of copper(II) sulfate with 3,5-dimethylpyridine (m(2)py) CuSO4 center dot 4m(2)py, takes the form [(O3SO)Cu(m(2)py)(4)], the Cu-O vector of the square-pyramidal coordination environment being disposed on the 4-axis in tetragonal space group P4/n. The complex CuCO3 center dot Cu(NCS)(2)center dot 4py is a linear polymer, taking the form ... O center dot Cu(py)(2)center dot O center dot C{O center dot Cu(py)(2)(NCS)(2)}center dot O center dot Cu(py)(2) ... (etc.), all atoms lying in the mirror plane of space group Pnma, excepting the pair of 'py' (pyridine) ligands disposed to either side. In Cu(OH)I center dot 3/4I(2)center dot 2py center dot 1/2MeCN [{(py)(2)Cu(OH)}(4)](I-3)(3)I center dot 2MeCN a novel cubanoid tetranuclear cation is found (2-symmetry). The EPR spectra of the above compounds show a trend in the anisotropy of the g-values that correlates well with the crystal structures. Obtained only in small quantities but supported by single crystal X-ray studies are the adduct of Cu(OH)Cl with pyrrolidine (pyrr), Cu(OH)Cl:pyrr (1:3), which takes the centrosymmetric binuclear form [(pyrr)(3)Cu(mu-OH)(2)Cu(pyrr)(3)]Cl-2, the copper atom being disposed in a distorted trigonal bipyramidal array, and the adduct 3CuCl(2)center dot CuO center dot 4quin, [Cu4Cl6O(quin)(4)]Cl-2, which contains the familiar Cu4Cl6O core with monodentate quinuclidine (quin) attached to the copper atoms; this compound crystallizes in the cubic space group (4) over bar 3m. (C) 2011 Elsevier B.V. All rights reserved.