Synthesis and characterization of thiocyanato-bridged heteropolynuclear chromium(III)-copper(II) complexes

Heteropolynuclear thiocyanato-bridged complexes were prepared in the reacti ons of aqueous solutions of K-3[Cr(NCS)(6)] with copper(II) complexes of th e type [CuX4](2+), where X = imidazole (imH), 4-methylimidazole (4-MeimH) a nd 2X = ethylenediamine (en). Solid products were formulated as (Cu(imH)(4) )(3)(Cr(NCS)(6))(2). 2H(2)O, (Cu(4-MeimH)(4))(3)(Cr(NCS)(6))(2). 3H(2)O and (Cu(en)(2))(3)(Cr(NCS)(6))(2). H2O on the basis of elemental analysis and spectral data (IR, UV-VIS). EPR spectra, variable temperature magnetic susc eptibility and thermal properties in air were investigated, indicating that all complexes are polynuclear with thiocyanate bridges, exhibiting Curie-W eiss behavior between 80-300 K. Thermal decomposition is multistage and yie lds CuO and CuCrO2 as final products.