The materials Ag@MIL-100(Fe) and Ag@UIO-66(Zr) are obtained for the capture and transformation of CO2 into alkynyl carboxylic acids, which are environmental friendly, facile to synthesize, and exhibit excellent efficiency and reusability. The influence on the catalytic activity of such Ag@MOF systems by metal–organic frameworks’ (MOFs) surface area, thermal, and chemical stability, especially the acid–base characteristics of the pores, are compared and discussed systematically.

A double active center system, namely Salen–Cu(II)@MIL-101(Cr), was successfully synthesized via the “ship in a bottle” approach, which acted as a bifunctional material for both capture and conversion of CO2 in a single process. For the first time, Salen–Cu(II)@MIL-101(Cr) catalyst was developed for the synthesis of propylene carbonate from CO2 and propylene oxide under room temperature and ambient pressure with a yield of 87.8% over 60 h. Furthermore, the reaction mechanism was also discussed.The composite catalyst Salen–Cu(II)@MIL-101(Cr) was synthesized by “ship in a bottle” method, which demonstrated excellent catalytic activity toward cycloaddition of CO2 to propylene oxide under ambient conditions.Download high-res image (77KB)Download full-size image

Pinene is a family of bicyclic monoterpenes found in nature, which exhibits important applications in chemical industry and biomedicine; however, the discrimination methods used for pinene enantiomers are still rare. The alpha- and beta-pinene enantiomers were recognized and discriminated via an electrochemical method for the first time based on a cyclodextrin metal–organic framework (CD-MOF) as an electrochemical chiral sensor.

Controlled assembly of 0D supramolecular nanocages into 2D or 3D architectures has been demonstrated for the first time via a coordination-driven polymerization approach, and the conversion from a 2D to 3D supramolecular architecture has also been successfully achieved via a temperature-induced crystal transformation. The boost of dimensionality for the supramolecular architecture has led to steady yet remarkable enhancement of properties, as reflected from the gas adsorption studies.

A water-stable copper metal–organic framework (MOF), {[Cu2(HL)2(μ2-OH)2(H2O)5]·H2O}n (1, H2L = 2,5-dicarboxylic acid-3,4-ethylene dioxythiophene), was applied for the electrochemical detection of ascorbic acid (AA) without further post-modification. A glass carbon electrode covered with 1 was used as a biosensor for the simultaneous detection of AA and L-tryptophan (L-Trp) from both a single-component solution and a bio-mimic environment.

The role of auxiliary solvents in the formation of metal–organic frameworks (MOFs) has been studied for a series of copper-based framework systems. Herein we show the formation of three different 3D ordered frameworks with the formulae {[Cu4(cpt)4Cl4]·2DMF·dioxane·3H2O}n (1), {[Cu8(cpt)4(Hcpt)2Cl7(μ3-OH)2(H2O)4]Cl3·4CH3CN}n (2), and {[Cu8(cpt)4Cl4(μ3-OH)2(μ4-O)2]Cl2·4H2O·2CH3CN·3MeOH}n (3) [Hcpt = 4-(4-carboxyphenyl)-1,2,4-triazole], respectively, from the same reaction mixture through varying auxiliary solvents of the medium. These MOFs were fully characterized by single-crystal X-ray diffraction, showing interesting secondary building unit (SBU) variations. The varied SBUs not only bring different framework architectures to these MOFs, but also affect their framework stability. Gas sorption studies of MOF 3 reveal high CO2–N2 selectivity at 298 K and 0.16 bar (a typical partial pressure of CO2 in an industrial flue gas). A high isosteric heat of adsorption (Qst) at zero loading (53 kJ mol−1) was also observed in MOF 3.

A new concept has been proposed and proven through model experiments for enhancing the adsorption selectivity of metal–organic frameworks (MOFs) and reducing the energy cost during the activation and regeneration processes.

A single-crystal to single-crystal (SC–SC) transformation process driven by water molecules has been exhibited by a multi-metallic coordination polymer. The in situ heating single crystal X-ray diffraction technique was applied to study the control of metal ion movement in the reversible SC–SC transformation process.

•Two novel Ni(II) complexes were synthesized by varying reaction temperatures.•A 0D to 3D transformation was achieved.•Magnetic properties of both complexes were characterized.Two new Ni(II) complexes, namely [NiL(bpy)0.5(H2O)2]·2H2O (1) and [NiL(bpy)0.5]n (2), respectively, were constructed from the same initial materials thiazolidine-2,4-dicarboxylic acid (H2L), 4,4′-bipyridine and NiCl2·6H2O, exhibiting varying architectures from 0D to 3D by changing reaction temperature. The transformation was confirmed by powder X-ray diffraction, infrared spectra and elemental analysis. The magnetic behaviors of 1 and 2 were investigated as well.Two new Ni(II) complexes were synthesized, which exhibited a structural transformation from 0D to 3D network through the variation of temperatures.

•Two designed semirigid ligands we used are rarely reported.•Four Co(II) complexes are firstly synthesized and characterized.•The Co(II) complexes can be modulated from 1D to 2D by modification of ligand substituent group.•An antiferromagnetic interaction occurs in four new Co(II) complexes.Four new coordination polymers [Co(btmtmb)2(SCN)2] (1), [Co(bttmb)2(SCN)2] (2), [Co(btmtmb)2(SeCN)2] (3) and [Co(bttmb)2(SeCN)2] (4), where btmtmb = 1,3-bis-(1,2,4-triazol-1-ylmethyl)-5-methoxy-2,4,6-trimethylbenzene and bttmb = 1,3-bis-(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethylbenzene, have been synthesized and structurally characterized. The X-ray crystal structures reveal that 1 and 3 are constructed of an infinite 1D chain, 2 and 4 contain a 2D (4,4)-network layer. Magnetic properties of the four complexes are investigated, which show that for all these four complexes the antiferromagnetic interactions occur and strong spin–orbit coupling of Co(II) ions exits as well.Four new Co(II) complexes with substituent-group-dependent 1D and 2D structures, respectively, were obtained based on two rarely reported semirigid ligands, which exhibit antiferromagnetic interactions and strong spin–orbit coupling of Co(II) ions.

Both bulk crystals and nanocrystals of two helical complexes, [Cu(μ2-L)(H2O)]n (1) and {[Cu(μ2-L)(H2O)]·2H2O}n (2) (H2L = thiazolidine-2,4-dicarboxylic acid), have been synthesized with the chiralities of right-handedness (1) and left-handedness (2), respectively. 4-Cyanopyridine and poly(vinylpyrrolidone) (PVP) have been applied to control the synthesis of complexes with different helicities in bulk-crystal and nanocrystal forms, respectively. 2 can be irreversibly transformed to 1 under heating. Associated with the conformation changing, the symmetry alters between nonpolar and polar space groups.

Two isomeric copper-containing coordination polymers, which are constructed from chiral ligand thiazolidine 2,4-dicarboxylic acid (H2L), have been synthesized with the same formula of [CuL(DMF)]n (1 and 1′). Complex 1 was prepared through the reaction of H2L and Cu(ClO4)2·6H2O in the mixture of N,N-dimethylformamide (DMF) and methanol (V/V = 1:1). With the same reactants 1′ was obtained only using DMF as solvent. Single-crystal X-ray diffraction analysis exhibited that 1 is left-handed helical chain and crystallizes in chiral space group P212121, while 1′ is right-handed helix with chiral and polar space group P21. In addition, both coordination polymers show obvious chiral and non-linear optical (NLO) properties, which were characterized by circular dichroism (CD) and second harmonic generation (SHG) measurements.Two novel copper-containing coordination polymers with chiral space group were synthesized by varying reaction solvents, which are isomeric one dimensional helical chain with different conformations (left-handedness and right-handedness).Highlights► Two novel chiral copper(II) complexes were synthesized by varying reaction solvents. ► The two complexes are isomeric 1D left- and right-handed helical chain, respectively. ► Both complexes exhibit chiral and non-linear optical properties.

•A new Cu6 cluster with high density of active Lewis acid sites was synthesized.•The cluster acts a good catalyst for the fixation of CO2 into cyclic carbonates.•The preparation of the cluster is very simple and rapid with low cost.A new Cu6 cluster [Cu6(μ4-O)2(SO4)4(DMA)6] (1) with high density of active Lewis acid sites turns out to be a good catalyst for the chemical fixation of CO2 into value-added cyclic carbonates without the use of any organic solvents under room temperature and atmospheric pressure. Above all, the preparation of 1 is very simple and rapid with low cost, which has important implications for industrial applications.Download high-res image (122KB)Download full-size image

A water-stable copper metal–organic framework (MOF), {[Cu2(HL)2(μ2-OH)2(H2O)5]·H2O}n (1, H2L = 2,5-dicarboxylic acid-3,4-ethylene dioxythiophene), was applied for the electrochemical detection of ascorbic acid (AA) without further post-modification. A glass carbon electrode covered with 1 was used as a biosensor for the simultaneous detection of AA and L-tryptophan (L-Trp) from both a single-component solution and a bio-mimic environment.

The role of auxiliary solvents in the formation of metal–organic frameworks (MOFs) has been studied for a series of copper-based framework systems. Herein we show the formation of three different 3D ordered frameworks with the formulae {[Cu4(cpt)4Cl4]·2DMF·dioxane·3H2O}n (1), {[Cu8(cpt)4(Hcpt)2Cl7(μ3-OH)2(H2O)4]Cl3·4CH3CN}n (2), and {[Cu8(cpt)4Cl4(μ3-OH)2(μ4-O)2]Cl2·4H2O·2CH3CN·3MeOH}n (3) [Hcpt = 4-(4-carboxyphenyl)-1,2,4-triazole], respectively, from the same reaction mixture through varying auxiliary solvents of the medium. These MOFs were fully characterized by single-crystal X-ray diffraction, showing interesting secondary building unit (SBU) variations. The varied SBUs not only bring different framework architectures to these MOFs, but also affect their framework stability. Gas sorption studies of MOF 3 reveal high CO2–N2 selectivity at 298 K and 0.16 bar (a typical partial pressure of CO2 in an industrial flue gas). A high isosteric heat of adsorption (Qst) at zero loading (53 kJ mol−1) was also observed in MOF 3.

A new concept has been proposed and proven through model experiments for enhancing the adsorption selectivity of metal–organic frameworks (MOFs) and reducing the energy cost during the activation and regeneration processes.

A single-crystal to single-crystal (SC–SC) transformation process driven by water molecules has been exhibited by a multi-metallic coordination polymer. The in situ heating single crystal X-ray diffraction technique was applied to study the control of metal ion movement in the reversible SC–SC transformation process.

Pinene is a family of bicyclic monoterpenes found in nature, which exhibits important applications in chemical industry and biomedicine; however, the discrimination methods used for pinene enantiomers are still rare. The alpha- and beta-pinene enantiomers were recognized and discriminated via an electrochemical method for the first time based on a cyclodextrin metal–organic framework (CD-MOF) as an electrochemical chiral sensor.