Synthesis, structures, and magnetic properties of four copper compounds with 2,2′-dinitrobiphenyl-4,4′-dicarboxylate?

Dalton Transactions Pub Date: 2012-08-14 DOI: 10.1039/C2DT31378B

Abstract

Four copper(II) coordination polymers of 2,2′-dinitrobiphenyl-4,4′-dicarboxylic acid (H2dnbpdc), with or without 4,4′-bipyridyl (bipy) as co-ligand, were synthesized under hydrothermal conditions and characterized crystallographically and magnetically. They are formulated as [Cu2(dnbpdc)(OH)2]n (1), [Cu(Hdnbpdc)2(bipy)]n·2nH2O (2), [Cu2(dnbpdc)2(bipy)(H2O)2]n·2nH2O (3) and [Cu3(dnbpdc)2(bipy)(OH)2(H2O)]n·nH2O (4). Compound 1 exhibits a 2D coordination network, in which infinite [Cu(μ-OH)(μ-COO)]n chains are linked by the backbones of the dnbpdc2? ligands. Magnetic studies indicated antiferromagnetic coupling through the mixed hydroxo and carboxylate bridges between CuII ions. In 2, mononuclear CuII centers are linked by Hdnbpdc? and bipy ligands into 2D grid-like layers. Compound 3 also consists of 2D grid-like coordination layers, which however are based on aqua-bridged Cu2(μ-OH2)2 units. Magnetic studies showed that the magnetic coupling through the double aqua bridges is antiferromagnetic. Compound 4 exhibits a 3D framework in which [Cu(OH)(COO)]n chains are linked by bipy and dnbpdc2? ligands. The chain has a complicated bridging network involving μ3-OH, μ2-OH and μ-COO, and magnetic studies revealed overall antiferromagnetic interactions within the chain.

Graphical abstract: Synthesis, structures, and magnetic properties of four copper compounds with 2,2′-dinitrobiphenyl-4,4′-dicarboxylate
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