Synthesis, topological structure and magnetism of a scarce homochiral octanuclear metallarectangle

Abstract

A scarce homochiral octanuclear copper(II) metallarectangle [Cu8L5(SO4)2(OH)2]•12H2O (L = bis(pyridin-2-ylmethylene)pyridine-2,6-dicarbohydrazide) has been synthesized and characterized. Single crystal X-ray diffraction discloses that eight Cu(II) centers are meshed and fixed by five L2− ligands arrayed in crossed manner, and the binding modes of the L2− ligands force the stereochemistry of the Cu(II) centers in the octanuclear metallarectangle into a decussation configuration which creates Λ chiralities at the Cu(II) centers. The octacopper metallarectangles are further fused together to create a 3D supramolecular network reinfored by the π···π stacking interactions involving the pyridine rings of the adjacent metallarectangles. Topology analysis reveals that each octanuclear rectangle can be considered as 6-connected node and each of the first kind of L2− ligands can be considered as 3-connected node, the consequent (3,6)-connected net can be rationalized as rtl topology with the short Schläfli symbol (4.62)2(42.610.83).