A Series of 1D, 2D, and 3D Coordination Polymers Based on Flexible 3-Carboxy-1-Carboxymethyl-2-Oxidopyridinium and Different N-Donor Ligands - Syntheses, Structures, and Luminescent Properties

Twelve new coordination polymers, namely, [Pb(L)] (1), [Mn-2(L)(2)(H2O)] (2), [Mn(L)(H2O)] (3), [Zn-3(L)(2)(H2O) 4] (4), [Zn(L)(pbib)(0.5)]center dot 1.5H(2)O (5), [Cd(L)(pbib)(0.5)]center dot 2H(2)O (6), [Zn(L)-(bbtz)(0.5)]center dot H2O (7), [Zn(L)(bbmb)(0.5)] (8), [Co(L)(bbmb)(0.5)(H2O)] (9), [Zn(L)(biim-6)(0.5)]center dot 2H(2)O (10), [Cd(L)(biim-6)(0.5)]center dot 2H(2)O (11), and [Cd(L)(biim-4)(0.5)]center dot 2H(2)O (12) have been synthesized under hydrothermal conditions [H2L = 3-carboxy-1-carboxymethyl-2-oxidopyridinium, pbib = 1,4-bis(imidazol-1-ylmethyl) benzene, bbtz = 1,4-bis(1H-1,2,4-triazol-1-ylmethyl)benzene, bbmb = 1,1'-(1,4-butanediyl)bis(2-methylbenzimidazole), biim-6 = 1,1'-(1,6-hexanediyl)bis(imidazole), and biim-4 = 1,1'-(1,4-butanediyl) bis(imidazole)]. Compound 1 features 1D double-chain structures, which are further linked by C-HuuuO hydrogen-bonding interactions to form a 3D supramolecular architecture. Compounds 2-11 have 2D layer structures. Compound 2 possesses a 2D (4(2).6(4)) layer. Compound 3 exhibits a 2D undulated 4(4)-squar lattice (sql) sheet. The 2D layers of 2 and 3 are further connected by intermolecular hydrogen-bonding interactions, which lead to 3D supramolecular architectures. The structure of 4 is a 2D (3,4)-connected net with the (4(2).6(2).8(2))(4(2).6) topology. Compounds 5-7 have similar structures and show 2D networks with 4-connected 4(4)-sql topologies. Compounds 8 and 9 have similar structures and display (3,4)-connected networks with the (4(2).6)(4(2).6(3).8) topology. Compounds 10 and 11 reveal similar 4-connected 44-sql nets. The 2D layers of 5-11 are further extended into 3D supramolecular architectures through p-p interactions. Compound 12 has a 3D (6(5).8) CdSO4-type framework. The thermal stabilities of 1-12 have been studied by thermogravimetric analysis. The luminescent properties for 4-8 and 10-12 have also been investigated in detail.