title: Synthesis, structures, and magnetic properties of four copper compounds with 2,2'-dinitrobiphenyl-4,4'-dicarboxylate.
abstract: Four copper(II) coordination polymers of 2,2'-dinitrobiphenyl-4,4'-dicarboxylic acid (H(2)dnbpdc), with or without 4,4'-bipyridyl (bipy) as co-ligand, were synthesized under hydrothermal conditions and characterized crystallographically and magnetically. They are formulated as [Cu(2)(dnbpdc)(OH)(2)](n) (1), [Cu(Hdnbpdc)(2)(bipy)](n)·2nH(2)O (2), [Cu(2)(dnbpdc)(2)(bipy)(H(2)O)(2)](n)·2nH(2)O (3) and [Cu(3)(dnbpdc)(2)(bipy)(OH)(2)(H(2)O)](n)·nH(2)O (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 dnbpdc(2-) ligands. Magnetic studies indicated antiferromagnetic coupling through the mixed hydroxo and carboxylate bridges between Cu(II) ions. In 2, mononuclear Cu(II) 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 Cu(2)(μ-OH(2))(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 dnbpdc(2-) ligands. The chain has a complicated bridging network involving μ(3)-OH, μ(2)-OH and μ-COO, and magnetic studies revealed overall antiferromagnetic interactions within the chain.
authors.affiliation: Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, Shanghai 200062, China.
authors.forename: Jian-Yong
authors.initials: JY
authors.lastname: Zhang
authors.forename: Xiu-Bing
authors.initials: XB
authors.lastname: Li
authors.forename: Kun
authors.initials: K
authors.lastname: Wang
authors.forename: Yu
authors.initials: Y
authors.lastname: Ma
authors.forename: Ai-Ling
authors.initials: AL
authors.lastname: Cheng
authors.forename: En-Qing
authors.initials: EQ
authors.lastname: Gao