Copper(ii) coordination polymers with azide and bipyridine-based zwitterionic carboxylate ligands: structures and magnetism

• DOI: 10.1039/c4dt01722f
• Publication Date: 2014-07-29T08:30:51Z
• Authors: Yu Ma; Ai-Ling Cheng; Bo Tang; En-Qing Gao
• Keywords: Carboxylate; Magnetism; Bipyridine

Two novel CuII coordination polymers, [Cu4O(L1)4(N3)2]n(ClO4)4n·3nH2O (1) and [Cu7(L2)2(N3)14]n (2), have been synthesized from two zwitterionic carboxylate ligands, 1-carboxylatomethyl-4,4′-bipyridinium (L1) 1-carboxylatomethyl-4,4′-dimethylenedipyridinium (L2). Compound 1 exhibits interpenetrated 3D diamond networks in which the unusual μ4-O-centred tetrahedral Cu4 clusters with peripheral 1,1-N3 COO bridges are cross-linked by 4,4′-dipyridinium-1-methylene spacers. In compound 2, pentanuclear dinuclear units double azide linked into a unique 2D layer μ3-1,1,3-N3, (1,1-N3)(COO) organic backbone of ligand. Magnetic studies reveal that ferromagnetic coupling through (μ4-O)(1,1-N3) antiferromagnetic μ4-O-only (μ4-O)(COO)2 pathways. 2 within (1,1-N3)2 bridged polynuclear weak between units.