title: Copper(II) coordination polymers with azide and bipyridine-based zwitterionic carboxylate ligands: structures and magnetism.
abstract: Two novel Cu(II) coordination polymers, [Cu4O(L(1))4(N3)2]n(ClO4)4n·3nH2O (1) and [Cu7(L(2))2(N3)14]n (2), have been synthesized from two zwitterionic carboxylate ligands, 1-carboxylatomethyl-4,4'-bipyridinium (L(1)) and 1-carboxylatomethyl-4,4'-dimethylenedipyridinium (L(2)). Compound 1 exhibits interpenetrated 3D diamond networks in which the unusual μ4-O-centred tetrahedral Cu4 clusters with peripheral 1,1-N3 and COO bridges are cross-linked by 4,4'-dipyridinium-1-methylene spacers. In compound 2, pentanuclear and dinuclear units with double azide bridges are linked into a unique 2D layer by μ3-1,1,3-N3, (1,1-N3)(COO) and the organic backbone of the zwitterionic ligand. Magnetic studies reveal that compound 1 exhibits ferromagnetic coupling through (μ4-O)(1,1-N3) and antiferromagnetic coupling through the μ4-O-only and (μ4-O)(COO)2 pathways. Compound 2 exhibits ferromagnetic coupling within the (1,1-N3)2 bridged polynuclear units and weak antiferromagnetic coupling through μ3-1,1,3-N3, and (1,1-N3)(COO) between the units.
authors.affiliation: College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Jinan 250014, P. R. China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Ma
authors.forename: Ai-Ling
authors.initials: AL
authors.lastname: Cheng
authors.forename: Bo
authors.initials: B
authors.lastname: Tang
authors.forename: En-Qing
authors.initials: EQ
authors.lastname: Gao