Resumo

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]₂•9.5H₂O 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]₂•9.5H₂O 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.