Three coordination polymers based on 4,4'-bis(2-methylimidazol-1-yl)diphenyl ether: Synthesis, structure and selective fluorescent sensing properties.

Three CPs [Zn2(PDA)2(BMIOPE)2·3H2O]n (1), [Co(Br-BDC)(BMIOPE)]n (2) and [Co(MIP)(BMIOPE)]n (3) were synthesized by solvothermal method based on dual-ligand strategy (H2PDA, Br-H2BDC, BMIOPE and H2MIP are 1,3-phenylenediacetic acid, 5-bromo-isophthalic acid, 4,4'-bis(2-methylimidazol-1-yl)diphenyl ether and 5-methylisophthalic acid, respectively). Complexes 1 and 3 exhibit twofold parallel interwoven sql nets. Complex 2 is 2D layer structure. The luminescence property investigations showed that complexes 1-3 could act as multi-responsive fluorescent sensors to detect UO22+, Cr2O72- and CrO42- and nitrofurantoin (NFT) through fluorescence turn-off process, presenting excellent sensitivity and selectivity. Finally, the possible fluorescent quenching mechanisms of complexes 1-3 toward the above pollutants are also further investigated by employing spectroscopic methods and quantum chemical calculations. The fluorescence lifetime measurements manifest the mechanism of fluorescence quenching is static quenching process.

A novel three-dimensional zinc(II) coordination polymer based on 3,3'-{[1,3-phenylenebis(methylene)]bis(oxy)}dibenzoic acid and 1,4-bis(pyridin-4-yl)benzene: synthesis, crystal structure and photocatalytic properties.

A novel three-dimensional (3D) ZnII coordination polymer, namely, poly[[[1,4-bis(pyridin-4-yl)benzene](µ3-3,3'-{[1,3-phenylenebis(methylene)]bis(oxy)}dibenzoato)zinc(II)] 1,4-bis(pyridin-4-yl)benzene], {[Zn(C22H16O6)(C16H12N2)]·C16H12N2}n or {[Zn(PMBD)(DPB)]·DPB}n, 1, where H2PMBD is 3,3'-{[1,3-phenylenebis(methylene)]bis(oxy)}dibenzoic acid and DPB is 1,4-bis(pyridin-4-yl)benzene, has been synthesized by self-assembly using zinc nitrate, a semi-rigid dicarboxylic acid and a nitrogen-containing ligand. The single-crystal X-ray structure determination indicates that 1 possesses an intriguing 3D architecture with a 4-connected uninodal cds topology, which is constructed from dinuclear {Zn2} clusters and V-shaped PMBD2- linkers. Compound 1 exhibits excellent photocatalytic activity on the degradation of the organic dyes Rhodamine B (RhB), Rhodamine 6G (Rh6G) and Methyl Red (MR).

Synthesis, structures and magnetic properties of two chiral mixed-valence iron(ii,iii) coordination networks.

Two rare chiral mixed-valence iron(ii,iii) coordination networks d-and l-{[FeIIFeO(BTC)3(DEF)3]·0.5H2O}n (d-1 and l-1) (H3BTC = 1,3,5-benzenetricarboxylic acid; DEF = N,N-diethylformamide) have been synthesized without any chiral auxiliary under the solvothermal conditions and structurally characterized by single crystal X-ray crystallography. Structural analysis indicates that these two polymers d-1 and l-1 are enantiomers. The only difference between d-1 and l-1 is that the framework of compound l-1 consists of left-handed double helical chains, while d-1 consists of right-handed double helical chains. Two distinct subunits (SBUs), {(µ3-O)Fe(COO)6(DEF)3} and {FeII(COO)6}, are observed in both structures simultaneously. The integration of two distinct SBUs leads to a trinodal (3,3,6)-connected net with an unusual structural topology. Interestingly, despite the achiral nature of H3BTC, the resulting framework exhibits rare chiral helical channels. The experiments show that dodecatungstosilic acid acts as a catalyst which could increase the conversion of the initial reactant. The magnetic studies indicate antiferromagnetic interactions between Fe3+ ions. Additionally, the luminescence studies revealed that the compound exhibited strong photoluminescence emissions at room temperature with a peak at 457 nm, owing to the strong interactions between organic linkers and metal clusters.