Hybrid materials composed of tetravanadate motifs: Synthesis, structure and magnetic properties of the open framework structure solids [{M(C 5H 5N) 4} 2]V 4O 12 (M = Cu, Co)

Abstract

Two new inorganic–organic hybrid materials – [{M(C 5H 5N) 4} 2]V 4O 12 (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 {V 4O 12} rings connected to {M(C 5H 5N) 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, μ eff, values for 1 and 2 are 1.9 μ B and 3.9 μ B, respectively, indicating some orbital contributions in each case. Both compounds exhibit Curie–Weiss magnetic behavior over the entire range above the critical temperature.