Synthesis, Crystal Structures And Properties Of The Coordination Polymers Constructed From Thiourea-Based Or Imidazole-Based Carboxylates

Recently, the design, synthesis, structures and properties of novel polymeric frameworks are the hotspot in coordination chemistry. Reasonable design of novel organic ligand bearing multi-coordination atoms is vital to the preparation of complexes. Thiourea-based and imidazole dicarboxylate ligands can be used to construct interesting structures with dirsed properties.Firstly, two similar thiourea-based ligands 2-(3-benzoylthioureido)propionic acid (H3L1) and 2-(3-benzoylthioureido)benzoic acid (H3L2) have been adopted to react with Cu(Ⅱ) or Mn(Ⅱ) ions in solution, and a rare 2-D cluster polymer [CuⅠ6CuⅡ6(L1)6(H20)10]n (1), a novel trimer [Cu3(L3)2(CH3OH)4] (3) and a 1-D polymer{[Mn(H2L1)2(CH3OH)2]·H2O}n (2) have been abtained. Complex 1 possesses 2-D sheet with unique mixed-valence [CuⅠ6CuⅡ6L6] subunits. Under the similar condition, complex 2 is a 1-D chain and compound 4 is a trinuclear complex. This may be due to the steric hindrance of the bulky phenyl group. Complex 2 has strong fluorescence performance at room temperature. There exists ferromagnetic or weak antiferromagnetic coupling between the neighboring Cu(Ⅱ) ions in 1 or 3, respectively; the best fittings to the experimental magnetic susceptibilities gave J=-12.06 cm-1, J'=-0.01 cm-1 and g= 2.21 for 3.Secondly, ten coordination polymers have been gotten by the reactions of 2-methyl-1H-imidazole-4,5-dicarboxylic acid (H3MIDC) with metal ions under hydro(solvo)thermal conditions. There are eight 3-D coordination polymers [Pb(HMIDC)]n (4), [Zn5(MIDC)2(HMIDC)2(phen)5]n(7),{[(M1)2(HMIDC)2(μ4-C2O4)(H2O)3].3H2O}n (M1=Nd (8) or Sm (9)),{[(M2)2(HMIDC)2(μ4-C2O4)(H2O)3]-EtOH·3H2O}n (M2=Eu (10) or Ce (11) or Pr (12)),{[Gd2(HMIDC)2(μ4-C2O4)(H2O)3]·4H2O}n (13) and two 1-D coordination polymers {[Mg(HMIDC)(H2O)2]·H2O}n (5), [Cd(HMIDC)(2,2'-bipy)]n (6) (2,2'-bipy=2,2'-bipydine, phen =1,10-Phenanthroline). Compound 4 exhibits a novel 3-D framework. Compounds 5 and 6 have the similar 1-D chain structures. Compound 7 exhibits a 3-D structure constructed from 2-D layer motifs joined byμ2-HMIDC2- orμ3-MIDC3- ligands. Complexes 8-13 are isomorphous and isostructural, and are all 3-D frameworks consisting of lanthanide-organic layers pillared by oxalate andμ2-HMIDC2- ligands. The thermal and properties and solid-state fluorescence spectra of complexes 4-13 have been determined as well. Complexes 5,6,7,9,10 and 13 show strong fluorescence performance at room temperature.