Hybrid materials composed of tetravanadate motifs: Synthesis, structure and magnetic properties of the open framework structure solids [{M(C5H5N)4}2]V4O12 (M = Cu, Co)

Two new inorganic–organic hybrid materials – [{M(C5H5N)4}2]V4O12 (M = Cu, 1; M = Co, 2) have been synthesized and characterized by spectroscopic methods, X-ray powder diffraction, thermogravimetry, magnetometry and complete single crystal structure analysis. The structures of 1–2 are comprised of layers containing centrosymmetric {V4O12} rings connected to {M(C5H5N)4} units by V–O–M bridges (M = Cu, 1; M = Co, 2). The layers are parallel to the (1 0 1) crystal planes and there are pyridine stacking interactions between layers. The effective magnetic moment, μeff, values for 1 and 2 are 1.9 μB and 3.9 μB, respectively, indicating some orbital contributions in each case. Both compounds exhibit Curie–Weiss magnetic behavior over the entire range above the critical temperature.