Role of aromatic dicarboxylates in the structural diversity of cobalt(ii) and copper(ii) coordination polymers containing a flexible N,N′-di(3-pyridyl)octanediamide ligand.

Six new transition metal coordination polymers, namely, [Co(1,2-BDC)(L)1.5(H2O)] (1), [Co(1,3-BDC)(L)(H2O)2]·H2O (2) [Co(5-AIP)(L)0.5(H2O)]·2H2O (3), [Cu(1,2-BDC)(L)] (4), [Cu(1,3-BDC)(L)(H2O)]·3H2O (5), and [Cu2(5-AIP)2(L)2(H2O)]·6H2O (6) (L = N,N′-di(3-pyridyl)octanediamide, 1,2-H2BDC = 1,2-benzenedicarboxylic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid, 5-H2AIP = 5-aminoisophthalic acid), have been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. In compound 1, the adjacent CoII ions are connected by L ligands to form a 1D chain with an alternating arrangement of L ligands and Co2L2 dinuclear loops. The 1,2-BDC anions coordinate with one CoII ion in a bis(monodentate) chelate mode. Complex 2 shows a 2D (44) grid network with the sql topology, which consists of the 1D zigzag [Co–L]n chain and 1D linear [Co-1,3-BDC]n chain. When 5-H2AIP is used in compound 3, an interesting 2D terraced-type layer based on 1D [Co-5-AIP]2n ladder-like chains and μ2-bridging L ligands with 3,4-connected {62.10}{6} topology is formed. Under the similar conditions to compound 1, except that the cobalt(ii) salt is replaced by a copper(ii) salt, a 2D wave-like network 4 with 2,4-connected {64.8.10}{6} topology is obtained. Compound 5 displays a 3D coordination polymeric architecture based on 1D [Cu-1,3-BDC]n chains and [Cu–L]n chains, which represents an intriguing 3-fold interpenetrating framework with CdSO4-type topology. When 1,3-BDC is replaced by 5-AIP, another 3-fold interpenetrating 3D CdSO4-type coordination framework for compound 6 is obtained, which is constructed from three types of 1D chains: [La–Cu–Lc]n chain, [Lb–Cu–Lb]n chain and [Cu-5-AIP]n chain. The adjacent 1D chains for 1 and 2D layers for compounds 2, 3 and 4 are further extended by hydrogen bonding interactions to 3D supramolecular frameworks. The effect of dicarboxylates and central metals on the structures of the title complexes has been discussed. Furthermore, the electrochemical behaviors and solid state fluorescent properties for compounds 1–6 are investigated. [ABSTRACT FROM AUTHOR]