title: Novel three-dimensional metal-azide network induced by a bipyridine-based zwitterionic monocarboxylate ligand: structures and magnetism.
abstract: The 4,4'-bipyridine-based zwitterionic monocarboxylate ligand, 4,4'-dipyridinio-1-acetate (L), is used as coligand to construct novel magnetic coordination polymers with mixed azide and carboxylate bridges. Two compounds, [Co(2)(L)(2)(N(3))(4)(H(2)O)] x 4 H(2)O (1) and [Mn(6)(L)(4)(N(3))(12)(H(2)O)] x 5 H(2)O (2), have been structurally and magnetically characterized. Compound 1 consists of one-dimensional (1D) coordination chains in which the unprecedented binuclear motifs with mixed (mu-EO-N(3))(mu-COO)(2) (EO = end-on) triple bridges are cross-linked by the 4,4'-dipyridinium-N-methylene spacers. In compound 2, the azide anions link the metal ions into a very complicated three-dimensional (3D) network with unprecedented topology, and the zwitterionic coligand is embedded in and serves as additional supports for the 3D network. Magnetic studies reveal that the mixed (mu-EO-N(3))(mu-COO)(2) triple bridges transmit ferromagnetic coupling in the Co(II) compound, and the overall antiferromagnetic interactions exist in the Mn(II) compound.
authors: Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, Shanghai 200062, China.
authors: Yu
authors: Y
authors: Ma
authors: Xiu-Bing
authors: XB
authors: Li
authors: Xiu-Chun
authors: XC
authors: Yi
authors: Qin-Xiang
authors: QX
authors: Jia
authors: En-Qing
authors: EQ
authors: Gao
authors: Cai-Ming
authors: CM
authors: Liu