Cooperative Catalysis between Dual Copper Centers in a Metal-Organic Framework for Efficient Detoxification of Chemical Warfare Agent Simulants.

Chemical warfare agents (CWAs) are among the most lethal chemicals known to humans. Thus, developing multifunctional catalysts for highly efficient detoxification of various CWAs is of great importance. In this work, we developed a robust copper tetrazolate metal-organic framework (MOF) catalyst containing a dicopper unit similar to the coordination geometry of the active sites of natural phosphatase and tyrosinase enzymes. This catalyst aided in phosphate ester bond hydrolysis and hydrogen peroxide decomposition, ultimately achieving high detoxification efficiency against both a nerve agent simulant (diethoxy-phosphoryl cyanide (DECP)) with a half-life of 3.5 min and a sulfur mustard simulant (2-chloroethyl ethyl sulfide (CEES)) with a half-life of 4.5 min, making it competitive with other reported materials. The dicopper sites in ZZU-282 provide versatile binding modes with the substrates, thereby promoting the activation of substrates and enhancing the catalytic efficiency. A combination of postmodified metal exchange control experiments, density functional theory calculations, and catalytic evaluations confirmed that dual Cu sites are the active centers promoting the catalytic reaction. This study offers a new design perspective to achieve advanced catalysts for CWA detoxification.

Phosphate anion-induced silver-chalcogenide cluster-based metal organic frameworks as dual-functional catalysts for detoxifying chemical warfare agent simulants.

Two porphyrinic silver-chalcogenide cluster-based MOFs were achieved using a phosphate anionic template strategy, and the highly photoactive organic building modules combined with Lewis acidic silver clusters allow both SCC-MOFs to be used as versatile catalysts for the simultaneous degradation of sulfur mustard and nerve agent simulants.

Small symmetry-breaking triggering large chiroptical responses of Ag70 nanoclusters.

The origins of the chiroptical activities of inorganic nanostructures have perplexed scientists, and deracemization of high-nuclearity metal nanoclusters (NCs) remains challenging. Here, we report a single-crystal structure of Rac-Ag70 that contains enantiomeric pairs of 70-nuclearity silver clusters with 20 free valence electrons (Ag70), and each of these clusters is a doubly truncated tetrahedron with pseudo-T symmetry. A deracemization method using a chiral metal precursor not only stabilizes Ag70 in solution but also enables monitoring of the gradual enlargement of the electronic circular dichroism (CD) responses and anisotropy factor gabs. The chiral crystals of R/S-Ag70 in space group P21 containing a pseudo-T-symmetric enantiomeric NC show significant kernel-based and shell-based CD responses. The small symmetry breaking of Td symmetry arising from local distortion of Ag-S motifs and rotation of the apical Ag3 trigons results in large chiroptical responses. This work opens an avenue to construct chiral medium/large-sized NCs and nanoparticles, which are promising for asymmetric catalysis, nonlinear optics, chiral sensing, and biomedicine.

Epitaxial coordination assembly of a semi-conductive silver-chalcogenide layer-based MOF.

Using a carboxylic acid linker, this work achieved the epitaxially coordinated assembly of a Ag-S layer into a three-dimensional semi-conductive framework, with high thermal stability, as well as an interesting temperature-dependent luminescence response. This work provides a new avenue to prepare semi-conductive metal-chalcogenide layer-based materials in electricity-related applications.

Electropolymerization of Metal Clusters Establishing a Versatile Platform for Enhanced Catalysis Performance.

Atomically precise metal clusters are attractive as highly efficient catalysts, but suffer from continuous efficiency deactivation in the catalytic process. Here, we report the development of an efficient strategy that enhances catalytic performance by electropolymerization (EP) of metal clusters into hybrid materials. Based on carbazole ligand protection, three polymerized metal-cluster hybrid materials, namely Poly-Cu14 cba, Poly-Cu6 Au6 cbz and Poly-Cu6 Ag4 cbz, were prepared. Compared with isolated metal clusters, metal clusters immobilizing on a biscarbazole network after EP significantly improved their electron-transfer ability and long-term recyclability, resulting in higher catalytic performance. As a proof-of-concept, Poly-Cu14 cba was evaluated as an electrocatalyst for reducing nitrate (NO3 - ) to ammonia (NH3 ), which exhibited ≈4-fold NH3 yield rate and ≈2-fold Faraday efficiency enhancement compared to that of Cu14 cba with good durability. Similarly, Poly-Cu6 Au6 cbz showed 10 times higher photocatalytic efficiency towards chemical warfare simulants degradation than the cluster counterpart.

Correction: Isopolymolybdate-based inorganic-organic hybrid compounds constructed by multidentate N-donor ligands: syntheses, structures and properties.

Correction for 'Isopolymolybdate-based inorganic-organic hybrid compounds constructed by multidentate N-donor ligands: syntheses, structures and properties' by Haiyang Guo et al., Dalton Trans., 2019, DOI: 10.1039/c9dt00119k.

Isopolymolybdate-based inorganic-organic hybrid compounds constructed by multidentate N-donor ligands: syntheses, structures and properties.

Taking advantage of isopolymolybdate [(NH4)6Mo7O24·4H2O] as a POM building block with multidentate N-donor molecules (tris[(2-pyridyl)methyl]amine = TPMA, 1-(tetrazo-5-yl)-3-(triazo-1-yl)benzene = 1,3-ttb) as organic ligands, five different inorganic-organic hybrid compounds were synthesized and characterized by single-crystal X-ray diffraction, infrared spectroscopy (IR) and powder X-ray diffraction (PXRD). Compound 1 is a Mo(vi)-based structure in which the TPMA ligand shows a tridentate coordination mode, which bears an uncoordinated pyridyl arm, and can further react with transition metals. Compound 2 exhibits a Cu(ii)-based zero-dimensional (0D) structure consisting of the TPMA ligand and [ß-Mo8O26] polyanion. Compounds 3 and 4 have the same molecular formula with slight structural differences; both have the Co(ii)-based one-dimensional (1D) chain structure. Compared to the ß-Mo8O26 polyanion in compound 3, the [Mo8O28]8- units condense via sharing two common terminal O atoms to form infinite [Mo8O26]n4n- chains in compound 4. Compound 5 is a Cu(ii)-based two-dimensional (2D) layer structure consisting of TPMA and 1,3-ttb mixed ligands and [ß-Mo8O26]. In addition, the electrochemical properties and photocatalytic activities for the degradation of two types of organic dyes were explored for several compounds.

Flexible and rigid dicarboxylic acids enable the assembly of achiral and chiral 3D Co(ii) metal-organic frameworks.

Two novel 3D Co(ii) metal-organic frameworks induced by flexible and rigid dicarboxylic acids [Co3(µ3-OH)(1,4-ttb)3(sa)]·3H2O (1) and Co2(µ3-OH)(1,4-ttb)(4,4'-bpdc) (2) (1,4-ttb = 1-(tetrazo-5-yl)-4-(triazo-1-yl)benzene, sa = succinic acid and 4,4'-bpdc = biphenyl-4,4'-dicarboxylic acid) have been successfully synthesized and characterized via X-ray single-crystal diffraction, powder X-ray diffraction (PXRD), FT-IR spectroscopy and TG analyses. In the structures of the compounds 1 and 2, the main ligand 1,4-ttb coordinates with Co(ii) ions to form 3D host frameworks with different cavities, and the auxiliary ligands sa and 4,4'-bpdc fill the 3D cavities. More strikingly, compound 2 is a chiral 3D metal-organic framework, in which 4,4'-bpdc acts as a rigid achiral ligand. Additionally, the electrochemical properties and magnetic properties of compounds 1 and 2 have been investigated.

Highly effective synthesis of a cobalt(ii) metal-organic coordination polymer by using continuous flow chemistry.

The coordination polymer [Co2L4(H2O)2]·CH3CN·H2O (HL = (E)-2-[2-(4-chlorophenyl)vinyl]-8-hydroxyquinoline) has been achieved with 95% yield by using an Asia flow synthesis system (chip reactor). Compared with the conventional batch-type methods such as diffusion, reflux and solvothermal reactions, higher yielding reactions carried out in a flow reactor have demonstrated that this technique is a powerful strategy to obtain coordination compounds.

Efficient Synthesis of Ir-Polyoxometalate Cluster Using a Continuous Flow Apparatus and STM Investigation of Its Coassembly Behavior on HOPG Surface.

Taking advantage of a continuous-flow apparatus, the iridium(III)-containing polytungstate cluster K12Na2H2[Ir2Cl8P2W20O72]·37H2O (1) was obtained in a reasonable yield (13% based on IrCl3·H2O). Compound 1 was characterized by Fourier transform IR, UV-visible, (31)P NMR, electrospray ionization mass spectrometry (ESI-MS), and thermogravimetric analysis measurements. (31)P NMR, ESI-MS, and elemental analysis all indicated 1 was a new polytungstate cluster compared with the reported K14[(IrCl4)KP2W20O72] compound. Intriguingly, the successful isolation of 1 relied on the custom-built flow apparatus, demonstrating the uniqueness of continuous-flow chemistry to achieve crystalline materials. The catalytic properties of 1 were assessed by investigating the activity on catalyzing the electro-oxidation of ruthenium tris-2,2'-bipyridine [Ru(bpy)3](2+/3+). The voltammetric behavior suggested a coupled catalytic behavior between [Ru(bpy)3](3+/2+) and 1. Furthermore, on the highly oriented pyrolytic graphite surface, 1,3,5-tris(10-carboxydecyloxy) benzene (TCDB) was used as the two-dimensional host network to coassemble cluster 1; the surface morphology was observed by scanning tunneling microscope technique. "S"-shape of 1 was observed, indicating that the cluster could be accommodated in the cavity formed by two TCDB host molecules, leading to a TCDB/cluster binary structure.