Hydrothermal Synthesis and Study of Inorganic-Organic Hybrid Vanadate of Nickel(II) Coordination Complex with Pyrazine, Ni3(C4H4N2)3(V8O23)

Abstract

The three-dimensional hybrid compound Ni3(C4H4N2)3(V8O23) has been synthesized by mild hydrothermal methods under autogenous pressure at 170 ºC, together with another hybrid phase, Ni2(C4H4N2)(V4O12)(H2O)2. The isolation of the title compound was carried out in order to characterize the phase. The structure of the phase is stable until 380 ºC, temperature at which the structure collapses due to the calcination of the pyrazine molecules. The IR spectrum shows the vibration modes of the pyrazine molecule and those of the [VO4]3- groups. UV-visible spectrum shows the characteristics bands of the Ni(II) d8-high-spin cation in a slightly distorted octahedral coordination. Magnetic measurements indicate the existence of antiferromagnetic interactions that can be fitted with a chain model, to give g= 2.31, J/k= -5.3, zJ’/k= -5.5.