Exchange coupled Co(ii) based layered and porous metal-organic frameworks: structural diversity, gas adsorption, and magnetic properties

Four new Co(ii) based metal-organic frameworks (MOFs) ({[Co3(L)(TDCA)3(DMF)2]n·2nCH3CN}) (1), ({[Co3(L)2(BDCA)3]n·2nCH3CN}) (2), {[Co2(L)2(CA)2]n·4nCH3CN} (3) and {[Co2(L)(OBBA)2]n·3nCH3CN} (4) are synthesized, where L is [4'-(4-methoxyphenyl)-4,2':6',4''-terpyridine], a V-shaped flexible neutral spacer, and the four dicarboxylates are TDCA = thiophene 2,5-dicarboxylic acid, BDCA = benzene 1,4-dicarboxylic acid, CA = (1R,3S)-(+)-camphoric acid and OBBA = 4,4'-oxybisbenzoic acid. Structural analysis reveals that 1 and 2 are two dimensional (2D) layered structures having interesting sql and hxl topologies respectively with trinuclear SBUs (secondary building units). Compound 3 has a 3D structure, whereas 4 has a 2-fold interpenetrated 3D packing structure with a paddlewheel dinuclear SBU and both have pcu topology. Magnetic investigation revealed that 1, 3 and 4 show dominant antiferromagnetic behavior, while 2 shows ferromagnetic interaction at very low temperature. Interestingly 4 shows a sharp decrease in the χMT value from room temperature and this may be because of the direct Co(ii)Co(ii) interaction. Gas sorption studies reveal that 1, 2 and 3 show surface areas of 11.8 m2 g-1, 8.3 m2 g-1 and 28.5 m2 g-1 respectively and better adsorption behavior for CO2 over CH4, whereas 4 is nonporous in nature due to its 2-fold interpenetrated structure.

A series of flexible bis(pyridyl)bis(tetrazole)-modulated coordination polymers: construction, electrochemical properties, dye adsorption and magnetic properties

Four new coordination polymers based on three bis(pyridyl)bis(tetrazole) ligands and 4,4′,4′′-benzene-1,3,5-triyltribenzoic acid were synthesized showing electrocatalytic, dye adsorption and antiferromagnetism properties.

Diversified magnetic behaviors of new nickel(ii) and copper(ii) azido coordination polymers templated by diethyl or triethyl amines

The reactions of Ni^II or Cu^II ions with N₃⁻ anions in the presence of templated diethyl or triethyl amines afford three new azido-bridged coordination polymers, which exhibit metamagnetism, spin glass and canted ferromagnetism, respectively.

Tuning the luminescence of two 3d–4f metal–organic frameworks for the fast response and highly selective detection of aniline

Two 3D solvent-stable zinc(ii)–lanthanide(iii) MOFs were synthesized, serving as recyclable and selective turn-off luminescent sensors for aniline detection.

A Zn(ii) complex with large channels based on 3′-nitro-biphenyl-3,5,4′-tricarboxylic acid: synthesis, crystal structure, fluorescence sensing of ATP, ADP, GTP, and UTP in aqueous solution and drug delivery

A 3D Zn(ii)–MOF with large cubic channels was synthesized. It showed fluorescence sensing of ATP, ADP, GTP, and UTP. Furthermore, it exhibited a remarkable capacity for and controlled release of 5-fluorouracil.

Coordination polymers of Fe(iii) and Al(iii) ions with TCA ligand: distinctive fluorescence, CO2uptake, redox-activity and oxygen evolution reaction

Remarkable differences in the physicochemical properties of metal–organic gels of Fe(iii) and Al(iii) ions with the TCA ligand is reported.

Composition dependence of magnetic relaxation for CoIIxNiII1−x chain-based compounds with mixed double azide–tetrazolate bridges

A series of isomorphous random bimetallic compounds based on CoIIxNiII1−x (0 ≤ x ≤ 1) chains with simultaneous azide–tetrazolate bridges exhibit composition-dependent magnetic relaxation were investigated.

Zinc and cadmium complexes based on bis-(1H-tetrazol-5-ylmethyl/ylethyl)-amine ligands: structures and photoluminescence properties

Nine zinc and cadmium coordination compounds with bis-(1H-tetrazol-5-ylmethyl/ylethyl)-amine were synthesized and structurally characterized, and the fluorescent emission and fluorescence lifetime of complexes 1–9 have been investigated and discussed.

Carbon functionalized metal organic framework/Nafion composites as novel electrode materials for ultrasensitive determination of dopamine

Carbon functionalized metal organic frameworks (C/Al-MIL-53-(OH)₂) were successfully prepared for the first time by a solvothermal technique and characterized by Fourier transform infrared spectroscopy, X-ray diffraction spectrometry, and scanning electron microscopy. This composite was coated with a Nafion film so as to form a Nafion/C/Al-MIL-53-(OH)₂ modified glassy carbon electrode. The modified electrode was then used as a novel electrocatalyst for dopamine (DA) oxidation in phosphate buffer solution. Due to the synergistic effects of the different materials, including the high conductivity of carbon, the large surface area of Al-MIL-53-(OH)₂, and the film-forming ability of a cation-exchange polymer, the modified electrode exhibited a remarkable enhancement effect on voltammetric response of DA. Under the optimal conditions, the response peak currents had a linear relationship with the DA concentration in the range from 3.0 × 10^-8 to 1.0 × 10^-5 mol L^-1. The limits of detection and quantitation for DA were found to be 0.8 × 10^-8 mol L^-1 and 2.6 × 10^-8 mol L^-1, respectively. The analytical utilities of the proposed biosensor were achieved by analyzing the content of DA in biological fluids.

Structural diversities and magnetic properties of azide-containing coordination polymers based on flexible tetra-pyridinate ligands

By utilizing two quadritopic ligands, four new azido-containing coordination polymers have been synthesized and structurally characterized.

Regulation of the pore size by shifting the coordination sites of ligands in two MOFs: enhancement of CO2 uptake and selective sensing of nitrobenzene

Two MOFs were constructed using azine functionalized and pyridyl based neutral ligands along with a V-shaped sdb linker, and exhibit highly efficient luminescence sensing for nitrobenzene and sorption selectivity for CO₂ over CH₄.

Concomitant spin-canted antiferromagnetic ordering and proton conduction in homometallic and homoleptic coordination polymers

Two oxonate based 1D zig-zag coordination polymers with Fe^II and Co^II are reported. These complexes are the first oxonate based systems to exhibit spin canted antiferromagnetic ordering at low temperatures and good proton conduction ability at elevated temperatures and under high humidity conditions.

Two robust metal–organic frameworks with uncoordinated N atoms for CO2adsorption

Two highly porous metal–organic frameworks are successfully constructed through the assembling of Co/Ni ions and mixed ligands. From the contribution of the uncoordinated tetrazolate N atoms of the ligand the two complexes show high CO₂adsorption capacities, serving as potential CO₂adsorption materials.

Syntheses, structures, magnetic and luminescence properties of a series of coordination polymers constructed from 1,4-naphthalenedicarboxylate and N-donor ligands

A series of coordination polymers constructed from 1,4-naphthalenedicarboxylate and N-donor ligands have been synthesized which forms four topological types. The thermal, magnetic and photoluminescence properties in solid state were also investigated.

Study of heterogeneous catalysis by iron-squarate based 3D metal organic framework for the transformation of tetrazines to oxadiazole derivatives

We present here a simple, milder, and environmentally benign heterogeneous catalytic method for the transformation of tetrazines to oxadiazole derivatives at room temperature (25 °C) using our earlier synthesized iron-squarate based 3D metal organic framework, [Fe3(OH)3(C4O4)(C4O4)0.5]n (FeSq-MOF).

A copper based pillared-bilayer metal organic framework: its synthesis, sorption properties and catalytic performance

A copper based metal organic framework with selective, hysteretic sorption, which can act as a heterogeneous catalyst for Glaser type homo-coupling reactions.

A family of three magnetic metal organic frameworks: their synthesis, structural, magnetic and vapour adsorption study

Three flexible magnetic metal–organic frameworks (MOFs) have been synthesized and their magnetic and adsorption properties were investigated.