Syntheses, structures, and photoluminescent properties of a series of coordination polymers based on a new 2′-carboxybiphenyl-4-ylmethylaminodiacetic acid and different N-donor ligands

Abstract

Ten new coordination polymers have been synthesized under hydrothermal conditions, namely, [Co3(L)2(H2O)3]·2H2O (1), [Zn3(L)2(H2O)3]·2H2O (2), [Co3(L)2(4,4′-bipy)2(H2O)4] (3), [Ni3(L)2(pbib)3(H2O)2]·4H2O (4), [Co3(L)2(bbtz)2(H2O)6]·2H2O (5), [Ni3(L)2(bbtz)2(H2O)6]·2H2O (6) [Zn3(L)2(bbtz)2(H2O)6]·2H2O (7), [Co3(L)2(pbib)2(H2O)4]·4H2O (8), [Co3(L)2(biim-4)2(H2O)4]·4H2O (9), and [Ni(L)(H2O)2]·H2O (10), where H3L = 2′-carboxybiphenyl-4-ylmethylaminodiacetic, 4,4′-bipy = 4,4′-bipyridine, pbib = 1,4-bis(imidazole-1-ylmethyl)-benzene, bbtz = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene, and biim-4 = 1,1′-(1,4-butanediyl)bis(imidazole). Their structures were characterized by infrared spectra (IR), powder X-ray diffraction (PXRD), and elemental analyses. Compounds 1 and 2 are isomorphous, and show the same 3D (3,4)-connected net with the (4·102)(4·85) topology. Compound 3 displays a typical 3D (3,4)-connected net with the (4·10·12)2(10·11·124) topology. Compound 4 reveals a 3D (3,6)-connected net with the (4·62)2(64·88·103) topology. Compounds 5–7 are isomorphous, and feature crystallographically distinct chains. Neighboring chains are stacked by π–π interactions to form 2D supramolecular layers, which are further extended by hydrogen-bonding interactions to form a 3D supramolecular architecture. Compounds 8 and 9 are essentially isomorphous with 5, and exhibit crystallographically distinct 1D chain structures. Adjacent chains are further extended into a 3D supramolecular architecture by hydrogen-bonding interactions. Compound 10 shows 1D chains, which are further linked by intermolecular hydrogen bonding interactions to generate a 2D supramolecular layer. The effects of the N-donor ligands and the coordination modes of L anion on the structures of the coordination polymers have been discussed in detail. In addition, the luminescent properties of compounds 2 and 7 have also been studied.