Wen-Huan Huang

Solvents influence on sizes of channels in three fry topological Mn(II)-MOFs based on metal–carboxylate chains: syntheses, structures and magnetic properties

Three new 3D Mn(II)-MOFs have been synthesized via solvothermal reaction with MnCl2·4H2O and [1,1′:4′,1′′-terphenyl]-2′,4,4′′,5′-tetracarboxylic acid (H4tptc) in three different solvents [N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMA) and N,N-dimethylformamide (DMF)], namely, [Mn2(tptc)(H2O)(NMP)]·NMP (1), [Mn2(tptc)(H2O)(DMA)]·DMA (2) and Mn2(tptc)(DMF)2 (3), all of which were fully characterized. In 1 and 2, the 1D uniform Mn–carboxylate chains with the (μ-EO-H2O/NMP/DMA)(μ-COO)2 triple bridges (EO = end-on) are extended by the tptc linkers to form a 3D (3,4)-connected fry net with 1D irregular quadrangular channels. Interestingly, 3 possess two kinds of Mn–carboxylate chains and can also be simplified as a fry net. The self-assembly synthesis system responds to small carbonyl solvents (NMP, DMA and DMF) with very high sensitivity and selectivity, but products using hydroxy solvents (methanol, alcohol and isopropanol) were not identified. The various pore frameworks of 1–3 are filled by different coordinated and latticed solvent molecules in their channels. The sizes of the channels [3 (33.11 A2) < 2 (35.17 A2) < 1 (35.37 A2)] are induced by the sizes of the solvent molecules (DMF < DMA < NMP). The good chemical stabilities of 1–3 were observed. Magnetic studies demonstrate that the magnetic coupling through the mixed carboxylate bridges in all compounds is antiferromagnetic.

Two new coordination polymers with multiform helical features based on flexible dithioether ligands and CuCN: from self-penetrating to 3-fold interpenetrating structures

The solvothermal reactions of CuCN with two structure-related flexible 4-pyridyl dithioether ligands, bis(4-pyridylthio)methane (L1) and 1,2-bis(4-pyridylthio)ethane (L2), generated two novel three-dimensional (3D) coordination polymers: [(CuCN)5(L1)2]n (1) and [(CuCN)3(L2)]n (2), respectively. Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses. Complex 1 is constructed by the interconnection of CuCN layers with L1 pillars to form an interesting self-penetrating 123 topological network with characteristic of four distinct helical chains. In 2, each L2 acting as a quadridentate μ3-bridge connects Cu atoms from three uncommon meso-helical CuCN chains, to give 3D framework containing 1D tubes constructed by two types of helical chains with opposite chirality. 2 exhibits a 3-fold interpenetrating network with a rare (62·10)2(6·102) topology. In addition, the solid state samples of 1 and 2 exhibited different luminescent properties at room temperature.

A stable 3D porous coordination polymer as multi-chemosensor to Cr(IV) anion and Fe(III) cation and its selective adsorption of malachite green oxalate dye

Based on Zn(NO3)2·6H2O and 4,4′-((5-carboxy-1,3-phenylene)bis(oxy))dibenzoic acid (H3cpbda), a 3D porous coordination polymer, {[Zn2.5(cpbda)(OH)2]·solvent2}n (solvent = DMF and DMA) (1), was synthesized by three solvent-thermal methods. The complex was characterized by single-crystal X-ray diffraction, IR spectroscopy, power X-ray diffraction, thermal-gravimetric analysis and fluorescence spectroscopy. Owing to its good thermal stability and fluorescence, the sensing experiments (eighteen kinds of cations and eleven kinds of anions) and the further titration processes show the complex can sensitively detect the Fe(III) metal cation and Cr(VI) anions (Cr2O72− and CrO42−) by the quenching responses. In addition, further adsorption research of seven dyes shows the complex 1 can selectively adsorb the Malachite Green Oxalate (MGO) dye.

The influence of ligand configuration, solvent size and solvent polarity on the porous shape and void volume in a series of isomeric or isomorphic porous MOFs

This article systematically reports various solvent systems and synthetic methods to induce isomerism and isomorphism in eight isomeric complexes. The “T” shape and “Y” shape configurations of the ligand lead to 1D “rectangle” shaped and “parallelogram” shaped channels in 3D frameworks. A solvent with a larger molar volume or lower solvent polarity is beneficial to construct porous MOFs with larger porous sizes and higher solvent void volumes. Solvent void volumes of 3D MOFs 6-3 > 6-2 > 6-1 > 1 > 4 > 3 corresponding to the coordinated solvent sizes DMP > DMA > DMF > MeOH > H2O and the coordinated solvent polarities DMP < DMA < DMF (polar aprotic solvents), < MeOH < H2O (polar protic solvents). It is notable that a suitable temperature and synthesis reactor are also crucial in the synthesis of porous MOFs. The related properties of complexes 1–6 are studied. The complexes which possess higher solvent void volumes are not thermally stable. Magnetic susceptibility measurements indicate that compounds 1–6 exhibit anti-ferromagnetic coupling between adjacent Mn(II) ions.