Surface defect-engineered Fe doping in layered Co-based complex as highly efficient bifunctional electrocatalysts for overall water splitting.

The electrocatalytic splitting of water to produce hydrogen is regarded as an efficient and promising strategy but is limited by its large overpotential; thus, a highly efficient electrocatalyst is urgently needed. Mixed metal doping is an important strategy in defect engineering because the heteroatoms can change the intrinsic structure to form defects by affecting the atomic coordination mode and adjusting the electronic structure, which is often accompanied by morphological changes. Herein, two-dimensional layered bimetallic Co-pydc containing axially coordinated water molecules was selected by producing surface defects through Fe doping in Co centers as bifunctional electrocatalysts for OER and HER. The optimized Co0.59Fe0.41-pydc possesses outstanding OER performance with the lowest overpotential of 262 mV to reach j = 10 mA cm-2, and Co0.75Fe0.25-pydc possesses superior HER performance with the lowest overpotential of 96 mV at j = 10 mA cm-2. Furthermore, the overall water splitting device assembled with Co0.59Fe0.41-pydc@NF//Co0.59Fe0.41-pydc@NF affords a current density of 10 mA cm-2 at only 1.687 V. This work emphasizes the surface defects formed by tuning the electronic structure of metal centres accompanied with morphological changes of bimetallic dopants for efficient overall water splitting.

Response of China's electricity consumption to climate change using monthly household data.

Intensifying climate change significantly impacts residential electricity consumption, especially in developing countries, such as China, that are experiencing rapid income growth. By combining meteorological and monthly household consumption survey data, this study explores the response function of residential electricity consumption to temperature in China from a micro perspective. Future residential electricity demands and related CO2 emissions are then forecast under different climate scenarios. Overall, the response function is U-shaped, and one additional day above 34 °C will increase monthly residential electricity consumption by 2.11%. Global warming will more likely increase the electricity burden on low-income groups. There will be notable seasonal changes in electricity demand in the future, and the largest increase will occur in August. The total demand for residential electricity caused by temperature change will show a fluctuating growth trend, from 0.8% and 1% in 2025 to 2% and 2.9% in 2060 under the RCP4.5 scenario and RCP8.5 scenario, respectively; meanwhile, this demand will be accompanied by a cumulative increase in carbon dioxide emissions.

In Situ Aliovalent Nickle Substitution and Acidic Modification of Nanowalls Promoted Proton Conductivity in InOF with 1D Helical Channel.

Proton-conductive materials have attracted increasing attention because of their broad explorations in chemical sensors, water electrolysis, fuel cells, and biological systems. Especially, metal-organic frameworks (MOFs) have been demonstrated to be extremely promising candidates as proton-exchange membrane (PEM) fuel cells. Compared with other configurations, MOFs with one-dimensional (1D) channels have the characteristics of enhancing the host-guest interaction and promoting the anisotropic motion of proton carriers in restricted volume, which are beneficial for acquiring rich proton sources and forming successive hydrogen bonds to improve proton conductivity. We are endeavored to screen and find a helical three-dimensional (3D) framework InOF-1, namely, [In2(OH)2(BPTC)]·6H2O (BPTC4- = 3,3',5,5'-biphenyl tetracarboxylate), as a typical 1D-channel MOF, which is pristinely grafted with spirally distributed -OH groups on the channel surface. Accompanied by an aliovalent substitution Ni(II) for In(III), isostructural NiOF-1 ([Ni2(BPTC)(HCOOH)2]·3H2O) is successfully prepared and massive formic acids are anchored at interior walls, which are interacted with adsorbed water molecules via the formation of stronger O-H···O bonds. This interaction between host-guest molecules and dynamics of lattice water has already led to a remarkable conductivity of InOF-1 (σ = 7.86 × 10-3 S/cm at 328 K under 95% RH). The synergistic effect of the acidic-modified nanowall, contracted volume, and enhanced adsorption of water molecules in the NiOF-1 channel contributes to a high conductivity value of 3.41 × 10-2 S/cm (at 328 K under 95% RH). Moreover, the proton conduction mechanism is further visually presented by molecular dynamic (MD) simulation. In contrast to InOF-1, aliovalent-substituted and acidic-modified NiOF-1 has a stronger host-guest interaction and more abundant hydrogen-bond networks, resulting in shorter proton migration distances and more frequent proton hopping, in agreement with the experimental results.

Polyoxotitanate Molecular Cage Featuring Four Types of Ethylenediamines: Formation Mechanism Insight from Host-Guest Interaction and Crystallographic Study.

Titanium-oxide or polyoxotitanate clusters are a new type of inorganic host materials that can encapsulate inorganic molecules or ions. We report herein a (NH4)4(enH2)[Ti18O27(PhCOO)24(en)9] molecular cage (Ti18) that encapsulates an entire organic ethylenediamine (en) ion. A thorough investigation has revealed the extraordinary versatility of en. Besides being a guest cation, it also functions as chelating and bridging ligand. It balances the charge of the negative Ti18 cage and facilitates the deprotonation of benzoic acid at the early stage of the reaction as well. DFT calculation and a derivative of Ti18 with open sites at its equatorial position shed further light on the formation mechanism. Ti18 strongly absorbs visible light as a result of en coordination, and it exhibits superior photocatalytic activity compared to anatase TiO2.

An uncoordinated tertiary nitrogen based tricarboxylate calcium network with Lewis acid-base dual catalytic sites for cyanosilylation of aldehydes.

The design and utilization of dual sites for synergistic catalysts has been recognised as an efficient method towards high-efficiency catalysis in the cyanosilylation of aldehydes, which gives key intermediates for the synthesis of a number of valuable natural and pharmaceutical compounds. However, most of the reported dual-site catalysts for this reaction were homogeneous, accompanied by potential deactivation through internal complexation of the dual sites. Herein, by the rational selection of an uncoordinated tertiary nitrogen based tricarboxylic ligand (tris[(4-carboxyl)-phenylduryl]amine, H3TCBPA), a new three-dimensional calcium-based metal-organic framework (MOF), Ca3(TCBPA)2(DMA)2(H2O)2 (1, where TCBPA = ionized tris[(4-carboxyl)-phenylduryl]amine and DMA = N,N-dimethylacetamide), possessing accessible dual catalytic sites, Lewis-basic N and Lewis-acidic Ca, has been designed and constructed by a one-pot solvothermal reaction. As expected, 1 is capable of dually and heterogeneously catalysing the cyanosilylation of aldehydes at room temperature, and can be reused for at least 6 runs with a maximum turnover number (TON) of 1301, which is superior to most reported cases. Additionally, 1 shows CO2 adsorption ability and conversion with epoxides, which is beneficial for the establishment of a sustainable society.

A quasi-D3-symmetrical metal chalcogenide cluster constructed by the corner-sharing of two T3 supertetrahedra.

Discrete supertetrahedral clusters of metal chalcogenides are rare because of the difficulty involved in meeting global charge matching between the negative charge of the skeleton and counterion. We present herein the third type of a discrete chalcogenide cluster with a double T3 structure in the compound (HDBN)6[In20S33(DBN)6] (DBN = 1,5-diazabicyclo [4.3.0]-5-nonene), the anion of which features quasi-D3 symmetrical double-T3 In20S33 supertetrahedra with six cornered indium atoms coordinated by DBN molecules. DFT theory calculations of the interaction between host and guest show that this compound may have high kinetic stability and low photoelectric reactivity.

Enhanced Proton Conductivity by Aliovalent Substitution of Cadmium for Indium in Dimethylaminium-Templated Metal Anilicates.

Metal-organic frameworks (MOFs) with excellent proton conducting ability are crucial to fuel cells, chemical sensors, and redox flow batteries, but achieving them remain a challenge because of the difficulty in simultaneous fulfillment of large number of proton carriers, high mobility of protons, and long-term durable proton conduction. To explore a simple, efficient, and general route toward highly proton-conducting MOFs, we propose herein an aliovalent substitution metal strategy for isostructural aminium-templated MOFs which benefit the acquisition of rich proton sources without modifying ligands or exchanging protic organic molecules. This idea is verified by 100-fold enhancement of conductivity in compounds (Me2NH2)2[Cd(mdhbqdc)2] (Cd-BQ) and (Me2NH2) (Me2NH)[In(mdhbqdc)2] (In-BQ) (H2mdhbqdc = dimethyl 3,6-dihydroxy-2,5-benzoquinone-1,4-dicarboxylic acid) that feature three-dimensional diamond-like structures with two-dimensional intersected channels. Accompanied by the in situ formation of an anilicate ligand, a great number of -OH groups are grafted onto the inner wall of pores, which interact with neutral Me2NH and/or protonated Me2NH2+ cations via N-H···O hydrogen bonds. The high concentration of protons and dynamics of protic amines in the porous framework readily leads to a moderate conductivity of In-BQ (2.10 × 10-4 S cm-1, at 303 K under 95% RH) and an activation energy of 0.73 eV (95% RH). It should be noted that the aliovalent substitution of Cd(II) for In(III) results in the doubling of dimethylaminium proton carriers in Cd-BQ, indicating more frequent hopping and multiple proton-transfer pathways. This indication is supported by a very high protonic conductivity of 2.30 × 10-2 S cm-1 and a reduced activation energy of 0.48 eV under the same conditions. Molecular dynamics simulations visually elucidate the fact that compared with In-BQ, aliovalent-substituted Cd-BQ has shorter proton-migration distances, which in combination with more proton numbers results in more frequent hopping and sliding of protons, in agreement with the experimental results.

Observation of Non-FCC Copper in Alkynyl-Protected Cu53 Nanoclusters.

The only feasible access to non-face-centered cubic (FCC) copper was by physical vapor deposition under high vacuum. Now, non-FCC copper is observed in a series of alkynyl-protected Cu53 nanoclusters (NCs) obtained from solution-phase synthesis. Determined by single-crystal X-ray crystallography, the structures of Cu53 (C≡CPhPh)9 (dppp)6 Cl3 (NO3 )9 and its two derivatives reveal an ABABC stacking sequence involving 41 Cu atoms. It can be regarded as a mixed FCC and HCP structure, which gives strong evidence that Cu can be arranged in non-FCC lattice at ambient conditions when proper ligands are provided. Characterization methods including X-ray absorption fine structure, XPS, ESI-MS, UV/Vis, Auger spectroscopy, and DFT calculations were carried out. CuII was shown to successively coordinate with introduced ligands and changed to CuI after bonding with phosphine. The following addition of NaBH4 and the aging step further reduced it to the Cu53 NC.

Optimized trimetallic benzotriazole-5-carboxylate MOFs with coordinately unsaturated active sites as an efficient electrocatalyst for the oxygen evolution reaction.

Exploring efficient and stable oxygen evolution reaction (OER) catalysts with earth-abundant elements has been an urgent task in water splitting. Metal-organic frameworks (MOFs), possessing abundant active metal sites and tunable porous crystalline structures, are promising as OER catalysts. In this paper, a MOF based on benzotriazole-5-carboxylate (Co3-btca) that contains unsaturated coordinated metal centers and a 1D channel was selected to act as an OER catalyst. To optimize the OER performance, isostructural bimetallic and trimetallic frameworks were obtained by doping with Fe and/or Ni ions. The optimized Co2.36Fe0.19Ni0.45-btca possesses the lowest overpotential of 292 mV at 10 mA cm-2 and a small Tafel slope of 72.6 mV dec-1. The enhanced catalytic performance could be attributed to the synergistic effect between the unsaturated coordinated Co, Fe and Ni sites, which are beneficial for the nucleophilic attack of OH- forming adsorption intermediates.

A new class of cuprous bromide cluster-based hybrid materials: direct observation of the stepwise replacement of hydrogen bonds by coordination bonds.

Although a variety of functional metal-organic frameworks (MOFs) have been synthesized, post-modified, and applied in various areas, there is little knowledge about how molecular cluster building units are stepwise evolved into MOFs via intermediates. Coordination bonds are generally stronger than hydrogen bonds, and thus equivalent replacement of X-H···Y hydrogen bonds by X-M-Y coordination bonds can transform hydrogen bond networks into MOFs. In this work, solvothermal in situ reduction reactions of CuBr2 and 1,4-diazoniabicyclo[2,2,2]octane (DABCO) generated a myriad of tunable photoluminescent cuprous body-centered cubic bromide cluster-based networks with the general formula [Cu4+xH4-xBr6(DABCO)4](HCO2)2·S (x = 0, 0.56, 0.81, 1.27, 1.39, 2.56, 2.78, and 4 for compounds 1-8, respectively). All of these compounds crystallize in the cubic space group with the largest volume difference being only 5.2%, but they belong to three remarkably different kinds of crystals. Complex 1 is a molecular crystal and consists of tetrahedral [Cu4Br6(HDABCO)4](2+) clusters with monodentate HDABCO groups that are supported via N-H···Br synthons in the hydrogen bond network. Compound 8 is a [Cu8Br6](2+) cube cluster-based MOF with bridged DABCO ligands. Complexes 2-7 are seemingly impossible Cu/H-substituted solid solutions of 1 and 8. The CuBr framework components in 1-8 are Cu4Br6, Cu4.56Br6, Cu4.81Br6, Cu5.27Br6, Cu5.39Br6, Cu6.56Br6, Cu6.78Br6, and Cu8Br6, respectively. Crystallization kinetics studies revealed that the [Cu4Br6(HDABCO)4](2+) cluster-based hydrogen bond network (1) was initially formed such that N-H···Br hydrogen bonds could be stepwise replaced by N-Cu-Br coordination bonds to form the [Cu8Br6](2+) cube cluster-based MOF (8) via solid solutions. These observations directly reveal the equivalence and transformation between the N-H···Br hydrogen bond and the N-Cu-Br coordination bond and the evolutionary mechanism of a molecular crystal to a MOF via solid solutions, which is of fundamental importance in materials but has never before been revealed. DFT calculations suggest that equivalent replacement of a N-H···Br hydrogen bond by a N-Cu-Br coordination bond is exothermic and exergonic, which also supports the transformation from molecule 1 to MOF 8.

Bis{N-[2-hy-droxy-1,1-bis-(hy-droxy-methyl)eth-yl]glycinato-κ(3) O,N,O'}iron(II).

In the title compound, [Fe(C6H12NO5)2], the Fe(II) ion lies on an inversion center and is coordinated by two N atoms and four O atoms from two tridentate N-[2-hy-droxy-1,1-bis-(hy-droxy-methyl)eth-yl]glycine ligands, forming a slightly distorted octa-hedral coordination environment. In the crystal, O-H⋯O, O-H⋯N and weak C-H⋯O hydrogen bonds link mol-ecules, forming a three-dimensional network.

Tuning of valence States, bonding types, hierarchical structures, and physical properties in copper/halide/isonicotinate system.

Seven cupric halide coordination polymers, namely [Cu5(OH)3Br3(ina)4] (1), [Cu5(OH)3Cl3(ina)4] (2), [Cu2(OH)Cl(ina)2] (3), [Cu3(OH)2Cl2(ina)2]·2H2O (4), [Cu3(OH)2Br2(ina)2]·2H2O (5), [Cu2Cl2(ina)2(H2O)2] (6), [Cu2Cl(ina)2(gca)(H2O)] (7), cupric complex templated cuprous halide [Cu(II)(Me-ina)2(H2O)][Cu(I)5Br7] (8), and organic templated cuprous halide Me2-ina[Cu2Br3] (9) (Hina = isonicotinic acid), were prepared from the starting materials of cupric halide and Hina via fine-tuning solvothermal reactions. According to valence states of copper, 1-7 are copper(II) complexes, 8 is a mixed-valent Cu(I,II) complex, while 9 is a Cu(I) compound. According to bonding types of halides, nine complexes can be classified as three types: complexes 1-3 include only normal X-Cu bond (X = halide); complexes 4-7 include normal X-Cu bond and X···Cu weak bond; complexes 8 and 9 include normal X-Cu bond and X···H-C halogen hydrogen bonds. Complexes 1 and 2 are isomorphic three-dimensional (3D) pcu topological metal organic frameworks (MOFs) with butterfly-like Cu4(µ3-OH)2X2 and steplike Cu6(µ3-OH)4 cores as nodes, showing strong ferromagnetic couplings. Complex 3 also is a pcu topological MOF with only butterfly-like Cu4(µ3-OH)2Cl2 clusters as nodes, presenting spin canting antiferromagnetic behavior. Isostructural 4 and 5 are Cu3(OH)2 clusters based two-dimensional (2D) (4,4) layers, which are extended into 3D eight-connected networks via weak Cu···X bonds, showing ferromagnetic coupling. Antiferromagnetic 6 is a simple one-dimensional coordination polymer, which is extended via weak Cu···Cl bonds into 3D (3,4)-connected networks. Paramagnetic 7 is a ladderlike polymer, which is extended into 2D (3,4)-connected layer via weak Cu···Cl bonds. The syntheses of polymeric cupric complexes 1-7 mainly result from differences in reactant ratio and pH value. Utilization of reducing methanol generated novel cubane-containing [Cu5Br7](2-) chain templated by paddlewheel-like [Cu(II)(Me-ina)2](2+) 8 and face-shared dimer-containing [Cu2Br3](-) chain templated by N-methylated and O-esterificated Me2-ina 9. Complex 9 exhibits a strong red emission and a weaker green emission upon excitation.

In situ alkylation of N-heterocycles in organic templated cuprous halides.

Five new cuprous halides formulated as [etpy][Cu(3)I(4)] 1, [mepy][Cu(2)Br(3)] 2, [mepy][Cu(2)I(3)] 3 [dmebpp][Cu(7)Br(9)] 4 and [dmeDABCO](4)[Cu(8)I(16)] 5 (etpy = N-ethylpyridyl; mepy = N-methylpyridyl; dmebpp = N,N'-dimethyl-1,3-bis(4-pyridyl)propane; dmeDABCO = N,N'-dimethyl-1,4-diazabicyclo-[2.2.2]octane) have been prepared by solvothermal reactions of a copper source, halides and N-heterocyclic ligands in alcoholic solution. 1 contains an unprecedented trigonal two-dimensional cuprous halide layer Cu(3)I(4)(-) constructed from trimeric Cu(3)I(8) units via sharing peripheral mu(3)-iodines; isostructural 2 and 3 contain infinite Cu(2)X(3)(-) chains in which the copper atoms are arranged into a ladder; 4 is composed of novel twofold helical cuprous halide chains Cu(7)Br(9)(2-) built up by CuBr(4) and CuBr(3); 5 contains an infinite edge-sharing tetrahedral chain with a periodic sequence of eight CuI(4) tetrahedra. In situ alkylation reactions of N-heterocycles with alcohols generated organic cationic templates, which played an important role in the control of the structures of anionic cuprous halides. A possible alkylation mechanism of N-heterocycles in the system has been proposed. The fluorescence properties of 1 and 4 were investigated. Time-dependent density functional theory (TD-DFT) calculations were carried out on the excited electronic states 1 of in order to understand the emission mechanism.

[Optimizing the extracting technique of ampelopsin from Ampelopsis cantoniensis Planch by a uniform design method].

OBJECTIVE: To optimize the preparation of ampelopsin from Ampelopsis Cantoniensis Planch. METHODS: The extraction and purification process was studied by the uniform design with the extract of ampelopsin content and purity as markers. The facters which influence the extraction and the purification of ampelopsin content were studied by uniform design. RESULTS: The optimum extraction and purification process: the concentration for alcohol was 90%, and refluxing quartic, 1.5 h each time; extraction by petroleum ether quintic, the mount of active carbon was 1 g/100 g of the medicine material, and recrystaling thrice. CONCLUSION: This extraction process has higher yield of ampelopsin and is available for production.

Two mixed-valence vanadium(III,IV) phosphonoacetates with 16-ring channels: H2(DABCO)[V(IV)O(H2O)V(III)(OH)(O3PCH2CO2)2].2.5H2O and H2(PIP)[V(IVO)(H2O)V(III)(OH)(O3PCH2CO2)2].2.5H2O.

Two isostructural mixed-valence vanadium phosphonoacetates H2(DABCO)[V(IV)O(H2O)V(III)(OH)(O3PCH2CO2)2].2.5H2O (1) and H2(PIP)[V(IV)O(H2O)V(III)(OH)(O3PCH2CO2)2].2.5H2O (2) have been synthesized. They crystallize in the orthorhombic space group Pnna with a = 7.0479(10) A, b = 15.307(2) A, and c = 17.537(3) A for 1 and a = 7.0465(9) A, b = 15.646(2) A, and c = 17.396(2) A for 2. X-ray single-crystal diffraction reveals that 1 and 2 have a three-dimensional open framework featuring 16-ring ellipsoid channels that are filled with doubly protonated 1,4-diazabicyclo[2,2,2]octanium/piperazinium cations and water molecules. According to the classification in metal-organic frameworks, 1 and 2 contain infinite (-O-V-)(infinity) chains that are cross-linked by "metalloligand" [VO(H2O)(O3PCH2CO2)2](4-) into a 3-D net of the sra topology. The temperature dependence of the magnetic susceptibility of 1 shows that the chi(m)T value in the range of 60-320 K is constant of 1.105 cm3 K mol(-1)/V2 unit, and upon further cooling, the chi(m)T value rapidly increases to 1.81 cm3 K mol(-1) at 2 K. The corresponding effective magnetic moment (mu(eff))/V2 unit varies from 2.97 mu(B) at 320 K to 3.80 mu(B) at 2 K. The magnetic data in the range of 2-320 K follow the Curie-Weiss law with C = 1.074 cm3 K mol(-1) and Theta= -1.34 K.

In situ formation of meso-2,2'-oxydisuccinate via intermolecular dehydration coupling of D,L-malic acid: first coordination polymer of 2,2'-oxydisuccinate involving ether oxygen coordination: [Cd2(meso-odsc)(H2O)].

The first coordination polymer of 2,2'-oxydisuccinate, [Cd(2)(meso-odsc)(H(2)O)](odsc =meso-2,2'-oxydisuccinate), was hydrothermally synthesized from CdSO(4) and D,L-malic acid; X-ray crystallography shows that the D,L-malic acid was transformed in situ into meso-odsc via intermolecular dehydration coupling.