Syntheses And Characterization Of Coordination Polymers From New Bisimidazole Ligands By The Mixed-Ligand Strategy

Over the past few decades,coordination polymers have increased much attention owing to their intriguing structural diversity and potential applications in catalysis,gas sorption/separation,luminescence,magnetism,and so on.However,it is difficult to synthesize entangled motifs with tailored structures and properties,because crystallization is a very complicated process,and the temperature,pH value,solvents and counter anions,can impose unpredictable impact on the final architectures.In this work,we designed and synthesized a series of bisimidazole ligands and constructed 16novel coordination polymers by the mixed-ligand strategy.Meanwhile,their thermal stability,optical properties and adsorption behaviors to organic dyes have been studied.The main results are as follows:1.Based on a flexible bisimidazole ligand 1-(4-?4-?1H-imidazol-1-yl?benzyloxy?phenyl?ibpi?as the building unit to construct novel CPs,we have synthesized eight new coordination polymers,namely[Cd?cba??ibpi?]?1?,[Cd?sdc??ibpi?]·H₂O?2?,[Cd₂?bpdc?₂?ibpi?₂]?3?,[Ni₂?sdc?₂?ibpi?₂?H₂O?₂]·H₂O?4?,[Cd₂?tdc?₂?ibpi?]·H₂O?5?,[Cd?Hbtc??ibpi?]?6?and[Co₂?tdc?₂?ibpi?₂·H₂O]·2H₂O?7?.Compound 1 exhibits a 2-fold parallel interpenetration of sql networks.Compound2 presents a 3-fold parallel interpenetration of sql networks.Compound 3 features a parallel polycatenation of 3-fold interpenetrated sql networks.Compound 4 shows a unique type of inclined interpenetration of sql networks.Compound 5 displays a 3-fold interpenetration of pcu network.Compound 6 exhibits a uninodal self-catenating mab network.Compound 7 shows an 8-connected self-catenating framework of 8T10topology with the point symbol(4²⁰·6⁸).The thermal stabilities and photochemical properties of compounds 1,2,3,5 and 6 have also been studied.2.Wedesignedandsynthesizedanewbisimidazoleligand bis(4-?2'-ethylimidazol-ylphenyl?sulfone?L?as the building unit to construct entangled MOFs.Three linear dicarboxylic acids with different length were also introduced.Successfully,we reported here three entangled MOFs,namely[Zn₂?cba?₂L₂]·2H₂O?8?,[Zn₂?bpdc?₂L₂]·11H₂O?9?and[Zn₄?sda?₄L₂]·14DMF?10?.Compound 8 shows a 4-fold interpenetration of dia net.Compound 9 presents an unusual 1D?3D polycatenane by the 4-fold interpenetration of 1D tubular net.Compound 10 exhibits a 3-fold interpenetration of pcu net.They have good luminescent properties and thermal stability.3.We designed and synthesized a new rigid bisimidazole ligand,2,6-bis?imidazole-1-yl?naphthalene?2,6-bin?as the building unit to construct new MOFs.Successfully,we have synthesized six new MOFs by the mixed-ligand strategy,namely[Cd₂?odc?₂?2,6-bin?₂]·?CH₃?₂NH?11?,[Cd₂?tdc?₂?2,6-bin?₂?H₂O?₂]?12?,[Cd₂?bzdc?₂?2,6-bin?₂]·4DMF?13?,[Cd₂?hfdc?₂?2,6-bin?₂]·H₂O?14?,[Cd₃?tpo?₂?2,6-bin?₃?H₂O?₄]·2DMF·2H₂O?15?and[Zn₃?btb?₂?2,6-bin?]·8DMF?16?.Comound 11 exhibts a three-fold interpenetration of 4T25 network.Compound 12presents a five-fold interpenetration of dia network.Compound 13 displays a 2D?2D three-fold inerpenetration of sql layers.Compound 14 features a 2D?3D parallel polycatenation of sql layers.Compound 15 exhibits an unusual 3,4,6-connected self-catenated network of 3,4,6T206 topology.Compound 16 shows a rare 3,8-connected self-catenated network of 3,8T72 topology.These compounds have been characterized by elemental analysis,thermogravimetric analysis?TGA?and X-ray crystallography.Meanwhile,their adsorption behaviors to organic dyes have been studied.Almost all of these compounds exhibit selective adsorption to anionic methyl orange.