Synthesis, Crystal Structures And Properties Of Semirigid Polycarboxylic Ligands And Their Complexes

In this paper, twelve coordination polymers（CPs） based on new semirigid carboxylate ligands and various N-donor ligands have been synthesized under solvothermal conditions. To understand these CPs completely, elemental analysis, IR, single crystal X-ray diffraction, powder X-ray diffraction（PXRD） and thermogravimetric studies have been carried out. Moreover, their magnetic and fluorescence properties also have been investigated.1. Four manganese（Ⅱ） coordination polymers have been successfully obtained, namely, [Mn（L₁）_0.5（bipy）_0.5（H₂O）]_n（1）, [Mn₂（L₁）（1,4-bimb）（H₂O）₂]_n（2）, [Mn（L₁）_0.5（4,4’-bibp）_0.5（H₂O）₂]_n（3）, [Mn₂（L₁）（phen）₂（H₂O）₄]_n（4）, where H₄L₁ = 5,5’-（[1,1’-biphenyl]-4,4’-diylbis（oxy））diisophthalic acid, bipy = 4,4’-bipyridine, 1,4-bimb = 1,4-bis（imidazol-1-ylmethyl） benzene, 4,4’-bibp = 4,4’- di（1H-imidazol-1-yl）-1,1’-biphenyl and phen = 1,10-phenanthroline. Complexes 1 and 2 possess three-dimensional（3D） pillared-layer frameworks, 2-fold and 3-fold interpenetration take place in 1 and 2, respectively. In complex 3, 2D layers are linked by hydrogen bonds, finally, exhibiting a 3D supramolecular architecture. Complex 4 is a 0D structure. Meanwhile, the magnetic behaviors of complexes 1 and 2 have been investigated and weak antiferromagnetic interactions between two Mn（Ⅱ） centres in them have been revealed.2. Four novel cobalt（Ⅱ） complexes {[Co₃（L₃）₂（dib）₃（H₂O）₂]·2H₂O}_n（5）,{[Co₃（L₃）₂（4,4’-bibp）₃（H₂O）₄]·2H₂O}_n（6）, {[Co（HL₃）（bidpe）]·H₂O}_n（7） and {[Co₂（L₃）（bib）_0.5（μ₃-OH）]·2H₂O}_n（8） have been prepared, where H₃L₃ = 3-（（6-carboxynaphthalen-2-yl）oxy）phthalic acid, dib = 1,4-di（1H-imidazol-1-yl） benzene, 4,4’-bibp = 4,4’-di（1H-imidazol-1- yl）-1,1’-biphenyl, bidpe = 1,1’-（oxybis（4,1-phenylene））bis（1H-imidazole）, bib = 4,4’-bis（（2-methyl-1H-imidazol-1-yl）methyl）-1,1’-biphenyl. Single crystal X-ray analysis reveals that complex 5 exhibits an infinite 2D framework formed by the L3- and dib ligands, complex 6 displays a 3D supramolecular architecture linked by hydrogen bonds, complex 7 features a 1D chain in which lattice water molecules locate with the help of hydrogen bonds, complex 8 is a homochiral 3D network with right-handed 43 and 21 helix. Additionally, the magnetic behaviors for 5–8 have also been studied, revealing antiferromagnetic interactions between Co（Ⅱ） ions in them.3. Two novel Zn（Ⅱ） coordination polymers, namely {[Zn₃（L₄）₂（bipy）₂（H₂O）₄}_n（9） and {[Zn（HL₄）（4,4’-bibp）}n（10） have been obtained by employing a tricarboxylate ligand（H₃L₄） and different N-containing ligands, where H₃L₄ = 4-（（6-carboxynaphthalen-2-yl）oxy）phthalic acid, bipy = 4,4’-bipyridine, 4,4’-bibp = 4,4’-di（1H-imidazol-1- yl）-1,1’-biphenyl. Single crystal X-ray analysis reveals that complex 9 exhibits a 2D layer framework formed by the L₃- and bipy ligands, complex 10 displays an infinite 1D structure with Zn₂ units built by 4,4’-bibp ligands. Moreover, 9 and 10 have been chosen as fluorescent probes to sense different metal ions, showing the obviously selective response to Fe³⁺ ion through luminescence quenching.4. Complex 11, namely {Co（H₂L₅）（1,4-dpb）₂}n have been built by a tetracarboxylate ligand（H₄L₅） and N-containing ligand, where H₄L₅ = 4,4’-（[1,1’-biphenyl]-2,2’-diylbis（oxy））diphthalic acid and 1,4-dpb = 1,4-di（pyridin-4-yl）benzene, it possess a 3D pillared-layer framework; {Zn（L₆）（H₂O）₂}_n（12） have been prepared by employing a tetracarboxylate ligand（H₄L₆ = 3,3’-（[1,1’-biphenyl]-2,2’-diylbis（oxy））diphthalic acid）, it exhibits a 2D layer framework.