Hydrothermal synthesis and study of an inorganic-organic hybrid vanadate of a nickel(II) coordination complex with pyrazine, Ni3(C4H4N2)3(V8O23)

Highlights: → A novel inorganic-organic hybrid vanadate of nickel(II) coordination complex with pyrazine has been synthesized hydrothermally. → The thermal and spectroscopic behavior has been studied. → The compound shows AFM interactions which has been fitted to a magnetic model of lineal chains. -- Abstract: The three-dimensional hybrid compound Ni3(C4H4N2)3(V8O23) has been synthesized by mild hydrothermal methods under autogenous pressure at 170 oC. The structure of the phase is stable until 380 oC. The removal of the pyrazine molecules from the structure induces its collapse. The IR spectrum shows the vibration modes of the pyrazine molecule and those of the [VO4]3- groups. A UV-visible spectrum shows the characteristic 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, and zJ'/k = -5.5.