Journal of the Brazilian Chemical Society
versão impressa ISSN 0103-5053
ISHIRUJI, Fabiana H. O.; SPEZIALI, Nivaldo L.; VAZ, Maria G. F. e NUNES, Fábio S.. Synthesis, crystal structure and properties of the cyano-bridged heteropolynuclear [Cu(meso)]3[Co(CN)6]29.5H2O compound. J. Braz. Chem. Soc. [online]. 2010, vol.21, n.7, pp.1195-1200. ISSN 0103-5053. http://dx.doi.org/10.1590/S0103-50532010000700006.
The novel compound [Cu(meso)]3[Co(CN)6]29.5H2O was prepared and characterized structurally, magnetically and spectroscopically (UV-vis, FTIR and EPR). The crystal structure is result of the self-assembly of three [Cu(meso)]2+ and two [Co(CN)6]3- units leading to a polymeric zigzag chain. Isolated [Cu(meso)(H2O)2]2+ units counterbalance the charge of the whole structure. The crystal packing shows a large hollow space in the structure and a significant number of water molecules are found in these cavities. Magnetic properties exhibited a very weak antiferromagnetic exchange interaction between the copper ions, with J = -0.3 cm-1. FTIR spectrum showed typical frequencies of n(O-H) at 3604 cm-1 and bridging and non-bridging n(CN) at 2184 and 2128 cm-1, respectively. The electronic spectrum of the title complex presented a broad and symmetric band at 547 nm, assigned to the overlaid z2 → x2-y2, xy → x2-y2 and (xz, yz) → x2-y2 transitions. EPR data at 77 K presented a typical axial spectrum with g// = 2.33 and g⊥ = 2.01, in accordance with the tetragonal distortion of the copper(II) ion as supported by the single-crystal X ray diffraction data.
Palavras-chave : polynuclear; cyano-bridge; single crystal X-ray diffractometry; antiferromagnetism.