Syntheses, Structures And Properties Of The Coordination Polymers Constructed From Imidazole Dicarboxylates Modified By P-tert-Butylphenyl Or Naphthy1Groups

The design and preparation of imidazole-4,5-dicarboxylic acid (H3IDC) and its derivatives have attracted much attention due to their strong coordination ability and various coordination modes. Herein, we hope to introduce bulky aromatic groups into the2-position of H3IDC, explore their coordination features, and the structures of the related coordination polymers.Firstly, we synthesized two new organic ligands,2-(p-tert-butylphenyl)-1H-imidazole-4,5-dicarboxylic acid (H3BuPhIDC) and2-(2-naphthyl)-1H-imidazole-4,5-dicarboxylic acid (H3NIDC). Then the coordination abilities of the two ligands were predicted by theoretical calculations. Secondly, through hydro(solvo)thermal reaction,12novel coordination polymers were obtained:{[Cd(μ3-HBuPhIDC)(H2O)]·2H2O}n (1),[Cd(μ3-HBuPhIDC)(4,4’-bipy)o.5]n (2),[Zn2(μ3-HBuPhIDC)2(CH3OH)2]n (3),[Mn2(μ3-HBuPhIDC)2(CH3OH)2]n (4),[Co(μ2-HBuPhIDC)(H2O)2]n (5),[Ni(μ2-HBuPhIDC)(H2O)2]n (6),{[Ni4(μ2-HBuPhIDC)4(H2O)4]·H2O}n (7),[Cd(μ3-HNIDC)(CH3CH2OH)]n (8),[Zn(μ3-HNIDC)(CH3OH)]n (9),[Sr(μ5-HNIDC)(H2O)]n (10),[Mn(μ2-HNIDC)(4,4′-bipy)]n (11) and [Mn2(μ2-HNIDC)2(phen)2]n (12). Their molecular structures were characterized by single-crystal X-ray diffraction, elemental analyses, and IR spectra. Complexes1and2are3D coordination polymers built by HBuPhIDC2-and Cd(Ⅱ) ions. The difference is that complex2contains auxiliary ligand,4,4′-bipy. Complexes3and4are homeomorphism and possess3D structures. Complexes5and6own1D straight chain structures. Complex7is a1D helical chain. Complexes8and9have3D homeomorphism structures with holes. Complex10reveals a2D net structure. Complex11shows a2D clathrate structure. Complex12appears a1D wavy chain. These complicated structural coordination polymers show that the two designed ligands indicate strong coordination ability, which confirm our theoretical predication.Finally, the thermal stabilities of the polymers have been determined in air. The results exhibit that the polymers from the H3BuPhIDC ligand are stable below200℃, and the Mn(Ⅱ) polymers11and12with the H3NIDC ligand are also stable up to380℃. The solid-state fluorescence properties of the Cd(Ⅱ) and Zn(Ⅱ) coordination polymers have been investigated as well.