Three New Coordination Polymers Based on One Reduced Symmetry Tripodal Linker

Three novel metal–organic frameworks, namely, {[(Zn4O)1/2(Zn3–OH)1/2L3/2O1/4(H2O)5/2(NO2)1/2]·(H2O)4}n (1), {[Cd3L2(H2O)4]·(H2O)9·DMA}n (2), and {[Co(HL)(4,4′-bibp)]}n (3; H3L = 5′-carboxyl-[1,1′:3′,1′′-terphenyl]-4,4′′-dicarboxylic acid, 4,4′-bibp = 4,4′-bisimidazolylbiphenyl, DMA = N,N-dimethylacetamide), have been synthesized under hydrothermal conditions. These compounds were characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Compound 1 reveals an unusual 3D structure with {4·52}{4·62}{42·52·68·83}{52·6}{53·65·82} topology based on Zn4O and Zn3–OH clusters. In compound 2, the H3L ligand assembles with Cd(NO3)2 to a 3D framework with sqc27 {4·62}2{42·610·83} topology. They are both three-dimensional frameworks containing one-dimensional channels. In compound 3, the HL2– anion and 4,4′-bibp both act as bidentate ligands and coordinate to Co cations to form a three-dimensional 4-connected uninodal network. In addition, the thermal stabilities for 1–3 and luminescent properties for 1 and 2 are also discussed in detail.