Xiaofei Kuang

Assembly of a metal-organic framework by sextuple intercatenation of discrete adamantane-like cages

Metal-organic frameworks form a unique class of multifunctional hybrid materials and have myriad applications, including gas storage and catalysis. Their structure is usually achieved through the infinite coordination of metal ions and multidentate organic ligands by means of strong covalent bonds. Threaded molecules such as catenanes and rotaxanes have largely been restricted to comprising components of two-dimensional interlocking rings or polygons. There are very few examples of the catenation of polyhedral cages. Although it has been postulated that the infinite extended architecture can be obtained from the polycatenation of a discrete cage based on such threading, this has not been documented to date. Here we describe an infinite three-dimensional metal-organic framework composed of catenated polyhedral cages, in which the framework is achieved by mechanical interlocking of all of the vertices of the cages. The three-dimensional polycatenated framework shows twofold self-interpenetration in its crystal packing. The penetration of polycatenanes creates nanosized voids into which the Keggin polyoxometalate anions are perfectly accommodated as counteranions.

Surface modification of polyoxometalate host-guest supramolecular architectures: from metal-organic pseudorotaxane framework to molecular box

Precise controlling of the pH value leads to the formation of a new type of metal-organic pseudorotaxane framework and supramolecular box within accommodating POMs guests.

A 2D polyoxometalate-based complex: spin-canting and metamagnetism

A novel polyoxometalate-based complex [Cu2(ptz)(H2O)(μ2-O)(Mo4O13)]·H2O (ptz= 5-(2-pyridyl)tetrazole) was synthesized using a hydrothermal method; it exhibits a two-dimensional network structure and the concomitant existence of spin canting and metamagnetism.

A (3,8)-connected metal–organic framework with a unique binuclear [Ni2(μ2-OH)(COO)2] node for high H2 and CO2 adsorption capacities

A rare binuclear [Ni2(μ2-OH)(COO)2]-based nickel–organic framework (1) composed of close-packed irregular octahedral cages possesses a new (3,8)-connected topology with the Schlafli symbol of (3·52)2(34·42·56·611·74·8). At 1.0 bar, this activated sample (1a) exhibits a considerably high H2 uptake of 203.2 cm3 g−1 (1.81 wt%) at 77 K, and a high CO2 uptake of 108.2 cm3 g−1 (21.3 wt%) at 273 K. In addition, 1a has good adsorption selectivity for CO2 over CH4 and N2.

Inflammation-restricted anti-inflammatory activities of a N-acylethanolamine acid amidase (NAAA) inhibitor F215

&NA; N‐Acylethanolamine acid amidase (NAAA) is a cysteine enzyme that catalyzes the hydrolysis of palmitoylethanolamide (PEA). Pharmacological blockage of NAAA elevates PEA levels and exerts powerful anti‐inflammatory activities. We have recently identified a highly potent NAAA inhibitor F215. Here, we demonstrated that F215 was an unusual inflammation‐restricted NAAA inhibitor. In lipopolysaccharides (LPS) induced acute lung injury (ALI) model, F215 markedly accelerated inflammation resolution, promoted clearance of neutrophils infiltration and alveolar repair in the lungs. F215 efficiently inhibited NAAA and protected endogenous PEA from degradation in ALI model, but it cannot readily suppress the NAAA activity in naïve mice. The inflammation‐restricted effect of F215 was further confirmed in the alveolar macrophage, F215 only increased PEA levels and exerted anti‐inflammatory effects in activated macrophages, but not in unstimulated macrophages. Moreover, we also showed that the pharmacological effects of F215 were restricted to the local inflamed skin elicited by 12‐o‐tetradecanoylphorbol‐13‐acetate (TPA), but not the normal tissues. We believe that F215 could be a useful probe to investigate the function of NAAA, as well as a potent anti‐inflammatory agent, and its inflammation‐restricted feature might offer a new approach to prevent potential side effects of systemic enzyme inhibition. Graphical abstract Figure. No caption available.

Synthesis and characterization of polyoxometalate-based silver(I) phenylethynide compounds with antibacterial and antifungal activities

Six new silver-phenylethynide compounds, namely, [(AgCCPh)4(AgCF3SO3)(DMSO)2] (1), [(AgCCPh)(Ag3PW12O40)(DMSO)8] (2), [(AgCCPh)(Ag3PMo12O40)(DMSO)8] (3), [(AgCCPh)(Ag4SiW12O40)(DMSO)10] (4), [(AgCCPh)8(Ag4SiW12O40)(DMSO)10] (5), and [(AgCCPh)16(Ag3PW12O40)(DMSO)8(H2O)2] (6), have been synthesized and structurally characterized by X-ray crystallography. These compounds exhibit a coordinated silver column structure with OTf−/POM anions serving as counter-anions (1, 6), an infinite chain structure based on the coordinated Ag4 aggregates and POM anions (2, 3) and a discrete molecular structure containing coordinated silver aggregates and POM anions (4, 5), respectively. The pure phases of 1–5 are obtained and identified. The antibacterial/antifungal activities of 1–5 are screened by the disk diffusion method against the bacteria strains Bacillus pumilus, Bacillus subtilis, Staphylococcus aureus and Escherichia coli and the fungi strains Aspergillus niger and Canidia albicans, and the MIC/MBC values are also measured. The cytotoxicity and biological toxicity test results showed that these compounds have low toxicity in both cells and animals.

Anion-π Interaction-Induced Room-Temperature Phosphorescence of a Polyoxometalate-Based Charge-Transfer Hybrid Material

Room-temperature phosphorescence (RTP) was realized for the first time in a polyoxometalate-based charge-transfer (CT) hybrid material bearing polyoxometalates (POMs) as electron-donors (D) and rigid naphthalene diimides (NDIs) as electron-acceptors (A), meanwhile, this hybrid material displayed photochromism as well. The significant D-A anion-π interaction induced an additional through-space charge-transfer pathway. The resulting suitable D-A CT states can efficiently bridge the relatively large energy gap between the NDI-localized 1 π-π* and 3 π-π* states and thus trigger the ligand-localized phosphorescence (3 π-π*).