A highly active and selective Au@UIO-67 catalyst has been assembled. Gold nanoparticles (AuNPs) are monodispersed on the UIO-67 surface of a porous metal–organic framework, the micropores in UIO-67 as templates for adsorbing Au ions and enhancing interaction between AuNPs and UIO-67, favoring the formation of isolated and well-dispersed AuNPs. The catalyst exhibits high catalytic activity and CO selectivity for the reverse water–gas shift reaction in a fixed-bed flow reactor.

•Synthesis and structure of metal-organic frameworks 1 ([Zn2(bpda)(chdc)2]∝) and Ln3+@1.•Cation exchange.•Aqueous encapsulation and sensitization of visible-emitting rare-earth cations.Luminescent metal–organic frameworks Ln3+@1 (1:[Zn2(bpda)(chdc)2]∝) were synthesized. Through cation exchange, the novel compound 1 was induced to capture Tb3+, Sm3+, and Eu3+, and the photophysical properties of the resultant visible-emitting complexes were studied. The layered complex 1 was demonstrated to encapsulate and sensitize visible-emitting lanthanide cations within aqueous solutions.

•Synthesis and structure of a series of new metal–organic frameworks•MOFs should be achieved by metal-ion potential and building blocks.•Enhancing the photocatalytic effect of the dye methyl blue a catalyst supportA series of new metal–organic frameworks (MOFs) composed of a transition-metal organic acid salt and 2, 5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene (3-bpdh) was prepared via diffusion in a H2O–MeOH solvent system. The results illustrated that MOFs self-assembly should be achieved by metal-ion potential and building blocks. The loading of MOF microcrystals with titanium dioxide resulted in the composite photocatalyst TiO2@ZnMOF, which exhibited excellent photodegradation (64%) of the dye methyl blue. Importantly, this approach provides an innovative way of enhancing the photocatalytic effect of MOFs with potential applications as a catalyst support.A series of new metal–organic frameworks (MOFs) composed of a transition-metal organic acid salt and 2, 5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene (3-bpdh) was achieved by metal-ion potential and building blocks. The loading of MOF microcrystals with titanium dioxide exhibited excellent photodegradation of the dye methyl blue.

•Synthesis and structure of cobalt metal–organic framework materials 1Co and 2Co.•Selective catalysis.•Catalytic properties of metal–organic frameworks controlled by their structural topologies.New metal-organic framework (MOF) materials 1Co [Co(AIA)(bpd)] and 2Co composed of cobalt salt, 5-aminoisophthalic acid (AIA), and 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene (bpd) are successfully synthesized by a temperature-controlled self-assembly reaction. 1Co exhibits a three-dimensional extended porous structure and oxidation catalytic property for the degradation of methyl orange (MO) (conversion 88%), and 2Co is a powder crystal and catalyzes the degradation of malachite green (MG) (conversion 71%). The assembling temperature of MOFs is shown to regulate structures to present not only high activity but also significant selectivity for the degradation of different dyes. Furthermore, microcrystals of 1Co and 2Co with different sizes and morphologies are obtained under various conditions. The results reveal that their catalytic activity for the degradation of organic dyes can be drastically affected by assembly conditions, especially the synthesis time and concentration of reactants. In addition, a detailed possible oxidation catalytic mechanism is proposed. The high flexibility of this strategy will certainly enhance new potential applications of micro/nano-MOFs.

•Synthesis and structure of metal–organic frameworks and catenane [FeAu(CN)2(bpd)m·xH2O]·yH2O.•Metal-to-ligand charge transfer.•Water-switching of spin crossover.The electronic switching centers of metal–organic frameworks (MOFs) and the catenane [FeAu(CN)2(bpd)m·xH2O]·yH2O are sensitive to the presence of small molecules, and reversibly uptake and release water. The switching centers arise from the presence of Iron(II) spin crossover (SCO) centers within the framework lattice, and the SCO behaviors emerge in dehydrated samples. The water-exchanging MOFs may realize previously undeveloped materials, which can aid the development of electronic devices such as molecular switches.Graphical abstract

A three-dimensional microporous coordination polymer with weakly coordinating solvate molecules, Co2(H2O)4(2,6-NDC)2(DMF)2·2H2O, 1, have been synthesized. The metal-organic framework 1 can undergo a structural transformation when the solvent molecules are removed, which is followed by the modulation of physical properties. This crystal-to-crystal transformation is reversible, and associated with a significant magnetic-susceptibility change: dropping the Curie constant from 5.947 cm3 K to 5.535 cm3 K and elevating the Weiss temperature from −65.3 K to −7.5 K when the solvent molecules are removed. The absorption properties of the desolvated 1 were studied for N2 and Ar, and some preference were found most probably due to the small pore sizes in the material.Graphical abstractHighlights► Synthesis and structure of a microporous complex Co2(H2O)4(2,6-NDC)2(DMF)2·2H2O. ► Selective absorption properties of microporous structure. ► Crystal-to-crystal reversible structural and functional transformation.

A trinuclear complex [CuII2(bpmen)2][MoIV(CN)8]∙8H2O was synthesized and structurally characterized, crystallized in the monoclinic system, space group Cc with cell constants a = 11.726(2)Å, b = 17.158(3)Å, c = 23.891(5)Å, β = 97.96(3)° and Z = 4. It exhibited thermally reversible photo-responsive properties on UV light irradiation through a MoIV to CuII charge transfer, which is potential interest for the molecular storage of information as a multifunctional molecule-based material.A trinuclear-cluster complex [CuII2(bpmen)2][MoIV(CN)8]∙8H2O was synthesized and exhibited thermally reversible photoresponsive properties on UV light irradiation through a MoIV to CuII charge transfer.Highlights► Synthesis and structure of a Mo–Cu trinuclear-cluster complex. ► The photoinduced charge transfer from MoIV(S = 0) to CuII (S = 1/2). ► Thermally reversible photoresponsive materials.

•Two new isostructural metal–organic coordination polymers were assembled in a MeOH-H2O solvent system.•Microcrystals of the coordination polymers were investigated.•The molecular skeleton determined selective catalytic properties.Two new isostructural metal–organic coordination polymers [{M(H2O)5}2(μ-4-bpdh)(oba)]∞ (M = Co, Ni), 1Co and 2Ni, respectively, were constructed from 4-bpdh (2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene) and oba (4,4′-oxybis(benzoic acid)) in a MeOH–H2O solvent system. The Co (Ni) ion was located in a hexa-coordinate environment surrounded by five aqua ligands and one 4-bpdh ligand, which bridged two metal centers to form a rod-like structure. Both the Co and Ni coordination polymers can catalyze methyl orange (MO) and malachite green (MG), showing that the unique molecular skeleton determines their properties. Interestingly, different central metal ions of 1Co and 2Ni result in the difference of degradation efficiency. Furthermore, microcrystals of 1Co (2Ni) with different sizes and morphologies were obtained under various conditions. Additionally, a detailed oxidation catalytic mechanism of MO and MG was proposed. These two highly active coordination polymers that are able to selectively degrade organic dyes will be useful in many practical applications.Two isostructural metal–organic coordination polymers [{M(H2O)5}2(µ-4-bpdh)(oba)]∞ (M = Co, Ni), 1Co and 2Ni, respectively, were synthesized in a MeOH–H2O solvent system. The two materials exhibited excellent catalytic abilities for the degradation of MO.

A highly active and selective Au@UIO-67 catalyst has been assembled. Gold nanoparticles (AuNPs) are monodispersed on the UIO-67 surface of a porous metal–organic framework, the micropores in UIO-67 as templates for adsorbing Au ions and enhancing interaction between AuNPs and UIO-67, favoring the formation of isolated and well-dispersed AuNPs. The catalyst exhibits high catalytic activity and CO selectivity for the reverse water–gas shift reaction in a fixed-bed flow reactor.