Vibrational spectroscopic studies of some dimethylpyrazine cadmium (II) tetracyanonickelate benzene clathrates: [Cd(C6H8N2)Ni(CN)4]·C6H6

Abstract

Two new cadmium dimethylpyrazine (2,3-dimethylpyrazine or 2,5-dimethylpyrazine) tetracyanonickelate benzene clathrates, [Cd(C6H8N2)Ni(CN)4]·C6H6, have been prepared in powder form and characterized by FT-IR spectroscopy, Raman spectroscopy, X-ray diffraction, thermal analyses and elemental analyses. Vibrational assignments are proposed for the bands of the host lattice and guest molecule. It is shown that the spectra are consistent with a proposed crystal structure for these compounds derived from X-ray diffraction measurements. The C, H, N, Cd and Ni analyses were carried out for all the compounds. Thermal behaviors of these compounds are followed using TG and DTA techniques. The FT-IR, Raman spectroscopic, XRD, thermal and elemental analyses results propose that these compounds are similar in structure to the Hofmann-type clathrates. Their structure consists of planar polymeric layers, {M–Ni(CN)4}∞, formed from Ni(CN)4 anions coordinated to the bridging 2,3- or 2,5-dimethylpyrazine molecules bound directly to the cadmium. The cadmium atoms are bound to four N atoms of the CN ions and, the Ni atoms are surrounded by four C atoms of the CN groups in a square-planar layer.