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Antimony sulfoselenide (Sb 2 (S,Se) 3 ) is a promising sunlight absorber material for solar energy conversion in photovoltaic (PV) cells and photoelectrochemical (PEC) photoelectrodes due to its excellent photoelectric properties. However, the obtained thin-film and back contact properties significantly influence the PEC performance of photocathodes, causing severe bulk recombination, carrier transport loss, and deteriorating half-cell solar-to-hydrogen (HC-STH) efficiency. This study introduces an intriguing dual back interface engineering strategy for Sb 2 (S,Se) 3 photocathodes by incorporating an intermediate MoO 2 layer and a secondary carrier transport channel of Au to strengthen charge carrier dynamics. The synergistic assembly of these dual back interface layers improves the growth kinetics and achieves the optimal orientation of Sb 2 (S,Se) 3 thin films by increasing substrate wettability. Moreover, by shortening the back contact barrier height and passivating defect-assisted recombinations, these dual back underlayers simultaneously enhance carrier transport and separation efficiencies. As a result, the photocurrent density of the champion Sb 2 (S,Se) 3 photocathode increases from 5.89 to 32.60 mA cm -2 , and the HC-STH conversion efficiency improves significantly from 0.30% to 3.58%, representing the highest value for Sb 2 (S,Se) 3 -based photocathodes. This work highlights the effectiveness of dual back interface engineering in promoting the PEC performance of chalcogenide photocathodes for solar hydrogen evolution applications., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Two novel Wells-Dawson polyoxometalate-based compounds, (H 2 bimb) 2 [{Ag 1.5 (bimb) 1.5 }(P 2 W 18 O 62 )] (1), (H 2 bimb) 2 [Ag(bimb)] 0.5 [Ag(eim) 2 ] 0.5 [P 2 W 18 O 62 ]·H 3 O (2) (bimb = 1,4-bis(imidazole-l-yl)butane, eim = ethyl(imidazole)), have been synthesized under hydrothermal conditions and characterized by IR, thermogravimetric, XRD and single-crystal X-ray diffraction analyses. In compound 1, two "U"-type bimb ligands are connected together viaπ interactions of Ag-C to form a ring unit. The ring unit alternately links with the "Z"-type bimb via an Ag-N bond to form an infinite Z-shaped {Ag 4 (bimb) 3 } n chain. The adjacent two {P 2 W 18 } clusters bonded to two Ag1 ions on two adjacent Z-shaped chains to form an inorganic dimer linker, which further joins the Z-shaped chains together, resulting in unique organic-inorganic alternating 2-D layers. Adjacent 2D layers are further aggregated together via Ag-O bonds between the Dawson cluster and the Z-type chain on different layers to yield a 3-D network with a new topology {10 3 } 2 {10}{4·10 2 } 4 {4 2 ·10 4 } 2 . In compound 2, the eim ligand was synthesized in situ from bimb, which acts as a small molecular ligand to alter the structure and adjust the catalytic activity of compound 2. Each Ag2 connects with the bimb ligand to form a linear {Ag(bimb)} chain. Adjacent chains are bonded together via the bimb ligand to generate a supermolecule 2-D layer, in which a Dawson dimer cluster as a guest molecule is embedded in both sides of the layer through supermolecule interactions. Such 2-D layers are further supported by Ag(eim) 2 units leading to 3D supermolecule nets. In addition, the compounds exhibit excellent electrocatalytic behavior and better photocatalytic degradation capability for typical dyes than other Wells-Dawson POMs.

A novel 3D polyoxometalate metal organic framework (POMOF), [{CuCu (H 2 O) 5 (pzc) 10 (pz) 6 }{P 2 W 18 O 62 } 2 ]·4H 2 O (1) (Hpzc = pyrazine-2-carboxylic acid, pz = pyrazine) has been hydrothermally synthesized and characterized by IR, TG, XRD, UV-vis and elemental analyses. In compound 1, the pzc and pz ligands are generated through in situ transformation from pyrazine-2,3-dicarboxylic acid (pzdc) to remove one or two CO 2 molecules. The ligands with four coordination modes connect nine crystallographically independent Cu atoms to form a super-big circle unit. Each ring unit is connected to the adjacent six rings via an edge-sharing way to form a 2-D Cu/pz/pzc MOF layer, which is further extended along two spatial directions by two kinds of insert modes to generate an interpenetrating and staggered 3-D metal organic network. The {P 2 W 18 } clusters as nine-node inorganic guest molecules are grafted on the Cu/pz/pzc framework forming a complex 3D POMOF with a new topology {4·6·8 3 ·10} 2 {4·6·8} 2 {4·6 2 ·8 2 ·10} 2 {4·6 3 ·8 2 } 2 {4·8 5 } 2 {4 2 ·6 2 ·8 2 } 2 {4 2 ·6 3 ·8}{4 3 ·6 7 ·8 13 ·10 10 ·12 3 } 2 {4} 6 {6·8 2 } 2 {6 2 ·8} 2 {6 4 ·8·10}{6} 2 {8} 4 . Additionally, compound 1 exhibits good electrocatalytic activity for the reduction of H 2 O 2 and effective photocatalytic degradation ability for three azo dyes under UV irradiation.

Herein, two Wells -Dawson-type arsenomolybdates, formulated as [Cu(pyr) 2 ] 6 [As 2 Mo 18 O 62 ] (1) and [Ag(pyr) 2 ] 6 [As 2 Mo 18 O 62 ] (2) (pyr = pyrazole), were hydrothermally synthesized and structurally characterized via single-crystal X-ray diffraction, elemental analysis, IR and UV-vis-NIR spectroscopies, XPS, XRD, and TG analysis. The structural analysis indicated that compounds 1 and 2 were isomorphic. They are the first reported 3D honeycomb structures of Wells-Dawson-type arsenomolybdates. The [M(pyr) 2 ] (M = Cu and Ag) connected with [As 2 Mo 18 O 62 ] 6- polyoxoanions to form the {8 12 ·12 3 }{8} 3 topological structure. The contributions of organic ligands, pH value, reaction temperature, and transition-metal (TM) to the construction of 3D networks were elucidated. Furthermore, compounds 1 and 2 exhibited fluorescence properties in the solid state at room temperature, highly efficient catalytic ability for the degradation of five organic dyes (MB, RhB, MO, AP, and CR) under UV irradiation, and obvious electrocatalytic activities for the reduction of H 2 O 2 . The mechanisms of photocatalysis and electrocatalysis have also been discussed in detail.

A 3D organic-inorganic hybrid compound based on the Lindqvist-type polyoxometalate, [{Cu(phen)}3{Cu(μ2-ox)3}{Mo6O19}] (1) (phen = 1,10-phenanthroline, ox = oxalate), has been synthesized under hydrothermal conditions and structurally characterized by elemental analysis, IR, TG, PXRD, XPS, UV-vis, and single-crystal X-ray diffraction. In compound 1, three C2O4(2-) ligands bridge one Cu atom and three Cu(phen) fragments to form a tetra-nuclear copper(II) coordination complex [{Cu(phen)}3{Cu(μ2-ox)3}](2+) unit. The six-node [Mo6O19](2-) clusters are interweaved by the 6-connected tetranuclear copper(II) complex units into an intricate 3D network structure, exhibiting a 4(12)·6(3)-nbo (sodium chloride-type) topology. Compound 1 exhibits the highest connectivity of Lindqvist-type POM hybrid materials. The electrochemical behavior of 1-CPE has been investigated in detail. Furthermore, a diffuse reflectivity spectrum of 1 reveals the presence of an optical band gap and the nature of semiconductivity with a large energy gap. A magnetic susceptibility study reveals predominant antiferromagnetic interactions between the Cu(II) bridge units.

A new cobalt-based polyoxometalate, (Himi)2[Bi(2)W2(0)O(66)(OH)(4)Co2(H2O)(6)Na(4) (H2O)14] · 17H2O (imi = iminazole) (BWCN) has been synthesized and structurally characterized. The inhibitory activities against selected human cancer lines were also determined in this study. The cell viability and chemoresistance of BWCN on human colon carcinoma HT-29 cells were assessed by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazoliumbromide), cell morphology changes, a comet assay and western blot analysis. The typical morphologic changes of apoptosis and DNA damage indicated that BWCN could have a distinct proliferation inhibitory effect on cancer cells. BWCN as a chemotherapeutic agent also induced apoptosis on HT-29 cells and showed a significant expression of cleaved-caspase-3. These results suggested that the active site of BWCN is the polymeric anion based on the basic tectonic block {BiW(9)}, and the possible mechanism is related to the interference of DNA synthesis in cancer cells.

Chaihu-Shu-Gan-San (CSGS), a traditional Chinese medicine formula, has been effectively used for the treatment of depression. However, studies of its anti-depressive mechanism are challenging, due to the complex pathophysiology of depression, and complexity of CSGS with multiple constituents acting on different receptors. In the present work, metabolomic studies of biochemical changes in the hippocampus and serum of chronic variable stress (CVS)-induced depression rats after treatment with CSGS were performed using ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). Partial least squares-discriminate analysis indicated that the metabolic perturbation induced by CVS was reduced by treatment with CSGS. A total of twenty-six metabolites (16 from the hippocampus and 10 from serum) were considered as potential biomarkers involved in the development of depression. Among them, 11 were first reported to have potential relevance in the pathogenesis of depression, and 25 may correlate to the regulation of CSGS treatment on depression. The results combined with a previous study indicated that CSGS mediated synergistically abnormalities of the metabolic network, composed of energy metabolism, synthesis of neurotransmitters, tryptophan, phospholipids, fatty acid and bile acid metabolism, bone loss and liver detoxification, which may be helpful for understanding its mechanism of action. Furthermore, the extracellular signal-regulated kinase (ERK) signal pathway, involved in the neuronal protective mechanism of depression related to energy metabolism, was investigated by western blot analysis. The results showed that CSGS reversed disruptions of BDNF, ERK1/2 and pERK1/2 in CVS rats, which provides the first evidence that the ERK signal system may be one of the targets related to the antidepressant action of CSGS.

Three new organic-inorganic hybrid compounds based on PMo12O40(n-) (n = 3 or 4) polyanions and Cu(I)-pz/Cu(I)-pz-Cl porous coordination polymers: [Cu(I)(pz)]3[PMo(VI)12O40] (1), [Cu(I)(pz)1.5]4[PMo(V)Mo(VI)11O40]·pz·2H2O (2), [Cu(I)3(pz)3Cl][Cu(I)2(pz)3(H2O)][PMo(V)Mo(VI)11O40] (3) (pz = pyrazine) have been hydrothermally prepared and characterized by elemental analysis, IR, TG, XRD, XPS and single-crystal X-ray diffraction. Compound 1 presents a three-dimensional Cu(I)-pz framework with cube-like chambers, into which PMo(VI)12O40(3-) Keggin ions are incorporated. Compound 2 shows a three-dimensional sandwich-like framework, and PMo(V)Mo(VI)11O40(4-) polyanions are located in the octagonal voids of every two-dimensional Cu(I)-pz 4(1)8(2) network structure. Compound 3 exhibits a two-dimensional Cl-bridged Cu(I)-pz-Cl double-layer structure, and two kinds of PMo(V)Mo(VI)11O40(4-) polyanions as bridging linkers connect two adjacent double-layers to form a three-dimensional organic-inorganic framework through Cu(I)-O bonds. Additionally, their electrochemical characters, electrocatalytic behaviors and solid state fluorescent properties at room temperature have been investigated in detail.

Three supramolecular materials based on different poly(oxomolybdophosphate) clusters, (H(2)imi)(6)(Himi)(4)[{Sr(H(2)O)(4)}(2){Sr ⊂ P(6)Mo(4)(V)Mo(14)(VI)O(73)}(2)]·17H(2)O (1), (H(2)(4,4'-bpy))(2)[Cu(2)Sr(2)Mo(12)O(24)·(OH)(6)(H(2)O)(6)(H(2)PO(4))(2)(HPO(4))(2)(PO(4))(4)]·5H(2)O (2), and (H(2)bim)(H(2)bim)[SrP(2)Mo(5)O(23)(H(2)O)(3)]·2H(2)O (3) (imi = imidazole, 4,4'-bpy = 4,4'-bipyridine, and bim = 2,2'-biimidazole), have been hydrothermally synthesized and structurally characterized by the elemental analysis, TG, IR, UV-vis, XPS and the single-crystal X-ray diffraction. Compound 1 is made up of unusual basket-shape [Sr ⊂ P(6)Mo(18)O(73)](10-) cages linked by [Sr(H(2)O)(4)](2+) fragments to yield unprecedented dimeric chains, which represent the first 1-D assemblies of basket-type POMs. Compound 2 exhibits a novel string constructed from sandwich-like [Cu(P(4)Mo(6)O(31))(2)] units and {Sr(2)Cu} trinuclear linkers. Compound 3 is the first chain of Strandberg-type polyoxoanions connected by Sr(2+) cations. All the 1-D chains are further packed into various 3-D supramolecular assemblies via strong hydrogen-bonding interactions. The electrochemical and electrocatalysis behavior of 1, 2, and 3-CPE have been investigated in detail.

A new molybdenum nickel phosphate, [H(2)en](3)Na(4)[Ni(H(2)O)(3)][H(30)(Mo(V)(16)O(32))Ni(14)(PO(4))(26)O(2) (OH)(4)(H(2)O)(8)] x 8 H(2)O 1, has been hydrothermally synthesized and structurally characterized. Compound 1 crystallizes in the monoclinic space group P2(1)/c with a = 18.6118(6) A, b = 20.9879(6) A, c = 22.9360(5) A, beta = 116.678(2) degrees, V = 8005.5(4) A(3) and Z = 2. The polyoxoanion of 1 exhibits an unusual divacant wheel-type cluster in which two {NiO(6)} octahedra are lost from the well-known "saturated" {Mo(16)TM(16)P(26)} wheel. The two vacant sites are occupied by two protonated ethylenediamines (H(2)en) via the strong hydrogen-bonding interactions between the surface O atoms of the polyoxoanions and the amine group derived from the H(2)en ligands. DC susceptibility measurements show that compound 1 exhibits strong antiferromagnetic interactions inside the wheel-type cluster.