One pot synthesis, structure and magnetic property of a pseudo-interpenetrated 2D copper framework based on coordinated 1,1′-biphenyl-3,3′,5,5′-tetracarboxylate and synthon

Abstract

A mixture of 1,1′-biphenyl-3,3′,5,5′-tetracarboxylate acid (abbreviated as H4bpta), 4,4′-bipyridine (abbreviated as 4,4′-bipy), and CuCl2·2H2O generates co-crystallization supramolecular solids [Cu2(cis-H2bpta)2(4,4′-bipy)2]n·nH4bpta·2nH2O (I) under hydrothermal condition and form of partly deprotonated cis-H2bpta2− firstly emerges in this work. Crystallographically, a 1:1 co-crystal is formed by co-crystallization of [Cu2(cis-H2bpta)2(4,4′-bipy)2] and H4bpta in self-assembled process. Structurally, the compound (I) exhibits two-dimensional (2D) double-layered nets with a pseudo-interpenetrated skeleton, one layer is characteristic of metal-organic moiety linked via cis-H2bpta2− and 4,4′-bipy spaces, and the other formed by O–H···O H-bonds presented in neutral H4bpta ligands. Interestingly, its mechanically interlocked structure is formed by hydrogen bonds, which results in an interesting interweaving framework with a new (3,4,5)-connected topological structure. Magnetic couplings between adjacent Cu(II) centers are mediated through double syn-syn carboxylate bridges. Magnetic susceptibility measurement indicates that (I) exhibits a dinuclear Cu(II) behavior with antiferromagnetic coupling (J = −35.69(1) cm−1).