Transition metal-catalyzed coupling reactions are powerful synthetic methods for the C-C bond formation. Many coupling reactions such as Heck reaction, Negishi coupling, and Suzuki coupling have been widely applied in the syntheses of pharmaceuticals, functional materials and fine chemicals. In those coupling reactions, a C(sp²)-C(sp²) bond is formed in high efficiency and selectivity. However, in contrast to the C(sp²)-C(sp²) couplings, the C(sp³)-C(sp³) couplings are more difficult and develop late. Because the C(sp³)-C(sp³) bonds are ubiquitous in organic compound, the C(sp³)-C(sp³) bond formation is the central task of research in organic chemistry. In the past two decades, a great effort has been devoted to the development of cross-coupling reactions between alkyls to construct C(sp³)-C(sp³) bonds and impressive progress has been achieved. Among the transition metal catalysts that have been used in the construction of C(sp³)-C(sp³) bonds, nickel was found to be a preferable one, exhibiting unique activity and selectivity. Nickel catalysts promote the activation of alkyl electrophiles via radical catalytic cycles and inhibit and/or manipulate β-H elimination reactions. Nickel has several variable valence states and can flexibly participate in tandem reactions and reductive cross-coupling reactions. All these characteristic natures contribute to the success of nickel catalysts in the construction of C(sp³)-C(sp³) bonds. In this review, we will describe the advances on the nickel-catalyzed C(sp³)-C(sp³) bond-forming reactions. The main contents of this review include:the cross-coupling of alkyl electrophiles with organometallic reagents; the coupling involving a C(sp³)-H bond activation in the presence of directing group; the coupling co-catalyzed by nickel and photocatalyst; the reductive coupling of two alkyl electrophiles; and the additions of nucleophiles or electrophiles to alkenes such as hydroalkylation and difunctionalization of alkenes. The review will focus on the latest developments of nickel-catalyzed alkyl coupling reactions in the past two decades. The mechanisms of each reaction are discussed in detail for understanding the reactions.

Transition metal catalyzed asymmetric reaction is a hot issue and a frontier of the research in current organic chemistry. The design and synthesis of new type of efficient chiral ligands and chiral catalysts, esspecially those with novel skeleton is the focus of research in asymmetric catalysis. Since 1990's, chiral ligands based on spiro skeletons have received increasing attention and gradually developed into a new type of chiral ligands with distinctive characteristics. The skeletons of the chiral spiro ligands developed from spiro[4.4]nonane with three chiral stereocenters to spirobiindane and spiro[4.4]nonadiene with only one axial chirality, as well as other types of spiro skeletons. Nowadays, the library of chiral spiro ligands contains a wide range of chiral spiro ligands with different skeletons, including chiral spiro monophosphorus ligands, diphosphine ligands, phosphine-nitrogen ligands, dinitrogen ligands, and etc. Many of these chiral spiro ligands and related catalysts not only have shown high catalytic activity and high enantioselectivity for various asymmetric reactions such as asymmetric hydrogenations, asymmetric carbon-carbon bond forming reactions, and asymmetric carbon-heteroatom bond forming reactions, but also have made the enantiocontrol of many catalytic asymmetric reactions, which are difficult in obtaining high enantioselectivities, more easily and possible. The chiral spiro skeleton has become a ‘privileged structure’, and chiral spiro ligands and catalysts have been used in the syntheses of different type of chiral compounds including chiral natural products and chiral drugs. The emergence of chiral spiro ligands increased the dynamism of research on finding new chiral ligands and catalysts, and promoted asymmetric synthesis chemistry. Henceforth, the focus of study in chiral spiro ligands will continue to be the development of new chiral spiro ligands and catalysts with high activity and high enantioselectivity. At the same time, the applications of chiral spiro ligands in the new catalytic asymmetric reactions, and in the asymmetric synthesis of bioactive chiral compounds, chiral natural products and chiral drugs will become a new focus of research.

Chiral transition metal complexes-catalyzed asymmetric hydrogenation is one of the most efficient methods for the synthesis of optically active compounds, and has been intensively investigated in the past decades. This review presents a brief overview on the progress in the transition metal-catalyzed asymmetric hydrogenation since the beginning of this new century from three aspects: (1) chiral ligands and catalysts; (2) new catalytic asymmetric hydrogenations; (3) new methods and new strategies in asymmetric hydrogenations. Chiral monodentate phosphorus ligands have been a renaissance from the beginning of new century, and many efficient chiral monophosphoramidites such as MonoPhos, SiPhos, DpenPhos have been developed. The chiral phosphine ligands with a chirality on the phosphorus atom (P-chirality), such as BenzP*, ZhanPhos, and TriFer, have also been explored. Chiral ligands with a spiro skeleton have been a highlight of design and synthesis of chiral ligands. The chiral spiro ligands such as SDP, SiPhos, SIPHOX, and SpinPHOX are very efficient in asymmetric hydrogenations. The iridium complexes of chiral spiro pyridine-aminophosphine ligands SpiroPAP is the most efficient molecular catalysts up to now with a turnover number (ratio of converted substrate to catalyst) over 4500000 in the hydrogenation of acetophenone. A number of breakthroughs have been made in the researches on new catalytic asymmetric hydrogenations. Highly enantioslective hydrogenations of unprotected enamines, heteroaromatic compounds, and N-H imines have been developed. New methods and strategies including self-assembled, dendrimerized, and ferromagnetic nanomaterials-loaded chiral catalysts with recyclability and reusability, the catalysts with “mixed” chiral ligands have also been successfully applied in the catalytic asymmetric hydrogenations. However, the chiral transition metal complexes catalyzed asymmetric hydrogenation still has many challenges and is looking forward to new breakthroughs in the future. In addition to the continuous developments of new chiral ligands and catalysts with high efficiency, high enantioselectivity, and high chemoselectivity, new strategies such as co-operative or relay catalysis are becoming focuses of the asymmetric hydrogenations studies.

Sodium ion batteries (SIBs) as a new chemical power source have recently attracted a great attention for large-scale energy storage owing to the abundance and low cost of sodium resources. In order to achieve advanced SIBs with high specific energy, long cycling lifetime and fast charge/discharge ability, efforts have been devoted to developing advanced electrode materials with large specific capacity, robust cycling stability and good rate capability, as well as functional electrolytes with high ion-conductivity and wide electrochemical window. Promising cathode materials include high-capacity layered oxides, high-potential fluorophosphates and long-lifetime phosphates. Available anode materials consist of highly stable Ti-based layered oxides and carbon materials, high-capacity elemental metals/non-metals and low-cost metal-based compounds. Effective electrolytes involve ester-based electrolytes and ether-based electrolytes. This review summarizes the recent advance of electrode materials and electrolytes for SIBs, mainly focusing on their electrochemical properties, existing challenges and resolution strategies.

The main thrust of this contribution is to review applications of numerical simulations to biological systems over the past 35 years-specifically classical molecular-dynamics simulations and related preferential sampling approaches aimed at exploring selected degrees of freedom of the molecular assembly. Arguably enough, structural biology and biophysics represent one of the greatest challenges for molecular dynamics, owing to the size of the biological objects of interest and the time scales spanned by the molecular processes of the cell machinery in which these objects are prominent actors. The reader is assumed to be fully familiarized with the basic theoretical underpinnings of molecular-dynamics simulations, which will be discussed here from a biological standpoint, emphasizing how the enterprise of modeling increasingly larger molecular assemblies over physiologically relevant times has shaped the field. This review article will further show how the unbridled race to dilate both the spatial and the temporal scales, in an effort to bridge the gap between the latter, has greatly benefitted from groundbreaking advances on the hardware, computational front-notably through the development of massively parallel and dedicated architectures, as well as on the methodological, algorithmic front. The current trends in this research field, boosted by recent, cutting-edge achievements, wherein molecular dynamics has reached new frontiers, provide the basis for an introspective reflection and a prospective outlook into the future of biologically-oriented, high-performance numerical simulations. Furthermore, alternatives to brute-force molecular dynamics towards connecting time and size scales will be discussed, in particular a class of approaches relying upon the preferential sampling of judiciously chosen, important degrees of freedom of the biological object at hand. These methods, targeted primarily at providing a detailed thermodynamic picture of the molecular process at hand, can be viewed as computational tweezers designed to dissect the latter by means of a reduced set of collective variables.

We built several supramolecular binary hydrogels based on tetra-proline modi?ed calix[4]arene (TPC) and various viologens. The obtained results show that the TPC gelation is mostly achieved with viologen bromides in acidic condition. The variation of viologen side-chains has notable impact on the properties of the hydrogels, such as the gel-sol transition temperature (T_gel) and morphology, which were evaluated by the combination of dropping-ball method, atomic force microscopy and scanning electron microscopy. The prepared hydrogels are significantly electro-responsive, as well as chemical-sensitive, pH-sensitive and thermo-reversible.

Binding free energy is the most crucial physical quantity for describing recognition-association of protein-ligand hybrids. Accurate estimation of protein-ligand binding free energies is of paramount importance in the field of drug design and biological engineering. However, the association process of protein-ligand hybrids is usually coupled with complex conformational changes of molecular objects, which is not amenable to the timescale of classical molecular simulations. This limitation makes it difficult to accurately estimate the protein-ligand binding free energies using classical free-energy calculation strategies. An effective solution is to apply geometric restraints to reduce the configurational space needed to be sampled, so as to boost up the convergence rate of simulations, and then calculate and deduct the contribution of these restraints to the binding free energy by post-processing. In this review, we firstly introduce the recent developments of three geometric restraints, namely, funnel, spherical, and seven-degree-of-freedom restraints, used in accurate binding free-energy calculations, with emphasis on the latest progress of the third one. Specifically, the theoretically rigorous seven-degree-of-freedom restraint describes translational, orientational, rotational, and conformational degrees of freedom by means of a center-of-mass distance, spherical angles, Euler angles and the root-mean-square deviation. Moreover, we demonstrate the theoretical backgrounds and methods of how to achieve accurate protein-ligand binding free-energy estimation by combination of geometric restraints and importance-sampling or alchemical algorithms. In the geometric routes, the degrees of freedom of the relative movement of the protein-ligand complex are addressed in a stepwise fashion by one-dimensional importance-sampling simulations. In the alchemical routes, a special thermodynamics cycle is designed, in which additional simulations are performed to address the contribution of the restraints. A general suggestion for how to choose a suitable strategy for a given molecular assembly based on our experience is provided. Last but not least, we discuss the applications and challenges of using accurate protein-ligand binding free-energy calculation methods in fields such as drug design, and present the possibility of extending these methods for investigating complex protein-protein interaction.

The reduction of esters to alcohols is one of the most important chemical transformations in the production of fine chemicals, such as pharmaceuticals, agricultural chemicals, fragrances, and biofuels. Homogeneous catalytic hydrogenation of esters represents a green, atom-economic, and sustainable alternative to conventional stoichiometric approaches, avoiding the generation of large amount of wastes and the difficulties arose in work-up procedure by using metal hydride reductants. Although challenges still exist, significant progress has been made in catalytic hydrogenation of esters over the last ten years. Numerous transition metal catalysts including noble metal (such as ruthenium, osmium, and iridium) complexes and base metal catalysts (such as iron, cobalt, and manganese) have been developed for the hydrogenation of esters. The ligands of the catalysts have been well studied. A wide range of bidentate ligands including diamines, amino-phosphines, pyridine-amines, N-heterocyclic carbene-amines, and bipyridines, tridentate pincer ligands containing diethylamine and pyridine skeletons, tetradentate ligands containing pyridine and bipyridine skeletons have been applied in the hydrogenation of esters. The efficiency of hydrogenation of esters has been significantly improved, and the highest turnover number (TON) reached 90000 for the hydrogenation of benchmark substrates such as ethyl acetate, ethyl benzoate, and γ-valerolactone. A significant breakthrough has also been made in the catalytic asymmetric hydrogenation of esters to chiral primary alcohols. The asymmetric hydrogenations of ketoesters, racemic δ-hydroxyesters, and racemic α-aryl/alkyl substituted lactones provided efficient methods for the asymmetric synthesis of optically active chiral diols including chiral 1,5-diols and 1,4-diols. The significant progress achieved in recent years in the area of homogeneous catalytic hydrogenation of esters to alcohols is presented in this review. The focus of this review are the development of ligands and catalysts, and the advances in the catalytic asymmetric hydrogenation of esters and lactones.

Chiral metal-organic frameworks have shown important applications in the identification and separation of enantiomers and asymmetric heterogeneous catalysis, owing to their structural diversities and multifunctionalities. Recently, the applications of chiral metal-organic frameworks have been expanded to other research fields, such as circularly polarized luminescence and chiral ferroelectrics. Compared with achiral metal-organic frameworks, it is highly challenging to synthesize chiral metal-organic frameworks, because the chirality introduction usually results in the difficulty of the crystallization and purification process for the design of chiral metal-organic frameworks. In this review, we discussed three main strategies that have been utilized to construct chiral metal-organic frameworks, including direct synthesis by chiral ligands, spontaneous resolution with achiral ligands or in the presence of chiral-template, and post-synthetic modification of achiral metal-organic frameworks. Moreover, the recent research progresses of chiral metal-organic frameworks in chiral molecular recognition, enantiomer separation, asymmetric catalysis, circularly polarized luminescence, and chiral ferroelectrics are discussed.

Thirty tributyltin carboxylates were synthesized using (Bu3Sn)2O as a precursor. The structures were studied by IR and NMR. The absorption frequencies of the carbonyl group markedly depended on the coordination no. of the tin atom. The chem. shifts of 119Sn and 13C and the 1J(119Sn-13Sn) coupling constants of the compounds were determine Small structural changes around the tin atom were reflected in the 119Sn chem. shifts. For tributyltin arylcarboxylates, a relationship between 119Sn chem. shifts and Hammett constants of the para-substituents was found. The biol. activities of same compounds have been studied. They may be used as fungicides for fruit.

Near infrared spectroscopy (NIRS) has been widely used in analyzing various real complex samples due to its superiority in fast and non-destructive determination. It is difficult, however, for the technique to analyze the components of micro-content, especially the inorganic components, because NIR spectrum contains only the weak signals of C—H, O—H and N—H, and inorganic components generally generate no response in the spectrum. In this review, the principle and applications of NIRS in analyzing inorganic components in environmental, soil, plant and bio-samples are summarized. The feasibility of applying NIRS in micro-inorganic analysis was proved by various applications of the technique in analyzing lake or river sediments, forest or farmland soils, straw, amaranth, clover, paprika, rice, wheat, meats, and sea foods. Because multivariate calibration technique is generally adopted in NIR spectral analysis, quantitative analysis can be achieved by modeling the spectral responses in which the interactions of the inorganic components and organic contents are included or by using the correlationship between the micro and macro components. However, the models must be used with care in such applications because they may fail when the predicted samples are heavily deviated from the calibration ones. Furthermore, applications of preconcentration techniques in NIR analysis are also summarized in this paper. By adsorption of an inorganic analyte onto the surface of a high efficient adsorbent from a dilute solution, the interactions between the analyte and the adsorbent can be directly measured by using NIR diffuse reflectance spectroscopy (NIRDRS), and the relationship between the contents of the analyte and the spectra can be modeled with multivariate calibration techniques. The adsorbents of functionalized resins, thiol-functionalized magnesium phyllosilicate clay, nano-hydroxyapatite, etc. have been studied for detection of micro inorganic ions in dilute solutions such as Hg²⁺, Ag⁺, Pb²⁺, Zn²⁺, Cu²⁺, Co²⁺, Ni²⁺, Cd²⁺ and Cr³⁺. The results of these studies showed that the adsorption can significantly improve the detection limit and fast detection can be achieved by NIRDRS measurements and multivariate calibration.

Strategic exploration towards a novel synthesis of colchicine based on the angular aryl-substituted azulenone 2a is reported. Unique reactivities of 2a are documented in this report which features the valency tautomerization of tropilidene ? norcaradiene. The starting azulenone 2a was readily prepared by an unusual condensation of bis-(trimethoxy)phenylketene with ethoxyacetylene according to an earlier discovery by Nieuwenhuis and Arens in 1958. Although the mechanism of this transformation was rationalized later by Woodward and Barton respectively, the synthetic value of this reaction has not been demonstrated so far. We envisioned an interesting strategy towards the synthesis of colchicine via an addition-ring expension pathway (2b→2c). Hydride reduction of 2a followed by acidolysis afforded a spirocycle 4 instead of the anticipated azulenone intermediate 2b, via presumably the vanlency tautomer 3a. Upon further hydride reduction and acidic hydrolysis 4 was converted into the rearranged azulenone 5 along with naphthalene 6. Treatment of azulenone 5 with triflic acid led to a bridge cyclic enone 8, a facile Friedel-Crafts type cyclization product. While mild acidic conditions resulted in the cleavage of the fused cyclopentenone. Azulenone 13 was readily prepared from 2a via partial hydrogenation, hydride reduction, and acidolysis. Upon treatment with triflic acid, 13 was transformed into the angular aryl-shifted enone 14 stereospecifically, via presumably a cationic cyclopropane intermediate 15. In summary, although azulenone derivatives 5 and 13 synthesized from 2a did not undergo the planned transformation, other intriguing reactivity patterns were revealed.

Twenty tribenzyltin carboxylates were synthesized by reaction of bis(tribenzyltin) oxide with corresponding carboxylic acids. The compounds were characterized spectrally and by elemental anal. The IR vibrational frequencies of the carboxyl group relate to bulk and electronic effects. A slight structural change of these compounds can reflect on the difference of 119Sn, 13C chem. shifts and their coupling constants

Chiral organoboron compounds are widely used in organic synthesis, materials science, medicine, and other fields, and the development of methodologies for the synthesis of these compounds is a highly active and rewarding area of research. Enantioselective transition-metal-catalyzed carbenoid insertion into heteroatom-hydrogen (X—H) bonds is an efficient strategy for the formation of carbon-heteroatom (C—X) bonds and related chiral centers. The enantioselective boron-hydrogen (B—H) bond insertion reaction provides an ideal approach to chiral organoboron compounds. In our previous study, we developed a copper-catalyzed asymmetric B—H bond insertion reaction of α-diazoesters with phosphine-borane adducts with high yields and high enantioselectivities. Herein, we report the first enantioselective B—H bond insertion reaction of α-diazoketones, another readily available carbene precursors. Firstly, various borane adducts were evaluated, and dimethylphosphine-borane gave the best result. Then, the reaction conditions were carefully optimized, and Cu(MeCN)₄PF₆/(R_a,S,S)-Ph-SpiroBOX proved to be the most efficient catalyst. Under optimal reaction conditions, the substrate scope of the reaction was investigated. A variety of α-diazoketones underwent the B—H bond insertion reaction affording the desired α-borylketones in good yields with moderate to good enantioselectivities (up to 83% ee). This reaction represents one of the few enantioselective X—H insertion reactions using α-diazoketones as carbene precursors. A typical procedure for the enantioselective copper-catalyzed B—H bond insertion of α-diazoketones is as follows: The powered Cu(MeCN)₄PF₆ (5.6 mg, 0.015 mmol, 5 mol%) and (R_a,S,S)-Ph-SpiroBOX (4a, 9.2 mg, 0.018 mmol, 6 mol%) were introduced into an oven-dried Schlenk tube in an argon-filled glovebox. After CH₂Cl₂ (3 mL) was injected into the Schlenk tube, the solution was stirred at 25 ℃ under the argon atmosphere for 2 h. Then dimethylphosphine-borane (2e, 22.8 mg, 0.3 mmol) and 1-diazo-1-phenylpropan-2-one (1a, 48.1 mg, 0.3 mmol) were introduced into the reaction tube subsequently. The resulting mixture was stirred at 25 ℃ until the diazo compound disappeared. After concentration in vacuo, the residue was purified by flash chromatography on silica gel (petroleum ether/acetone, V:V=6:1) to give (+)-1-(dimethylphosphine- boryl)-1-phenylpropan-2-one (3ae, 52.4 mg, 0.252 mmol, 84% yield) as a colorless oil.

Lithium-rich manganese-based oxides (LRMO) are promising cathode materials to build next generation lithium-ion batteries because of high capacity and low cost. However, the severe capacity fade and voltage decay, which originate from surface oxygen loss, side reactions and irreversible phase transformation, restrict their practical application. Proposed approaches to address these issues include electrolyte modification, synthesis condition optimization, tuning elemental composition, bulk doping and surface coating. Surface coating has been proved to be an effective method to stabilize the interface between LRMO and electrolyte. Herein, we report a facile approach to synthesize Li₃PO₄-coated LRMO (LRMO@LPO) by in-situ carbonate-phosphate precipitate conversion reaction. The formation of Li₃PO₄ layer and its contribution to enhanced electrochemical performance are investigated in detail. Transmission electron microscopy (TEM) reveals that the surface of carbonate precursor converts to Ni₃(PO₄)₂ after reacting with Na₂HPO₄ solution, which finally transforms to Li₃PO₄ coating layer with thickness below 30 nm during calcination process. Quinoline phosphomolybdate gravimetric method gives the optimal Li₃PO₄ coating content of 0.56%. The modified LRMO@LPO sample exhibits improved cycling stability (191.1 mAh·g^-1 after 175 cycles at 0.5C between 2.0~4.8 V and 81.8% capacity retention) and suppressed voltage decay (1.09 mV per cycle), compared with bare LRMO material (72.9% capacity retention, 1.78 mV per cycle). The electrodes are studied by galvanostatic intermittent titration technique, electrochemical impedance spectroscopy, TEM and inductively coupled plasma atomic emission spectrometry. The results suggest efficient mitigation of phase transformation and dissolution of transition metal in LRMO@LPO. As a coating material with lithium-ion conductivity, Li₃PO₄ not only acts as a physical barrier to inhibit side reaction between the electrolyte and LRMO, but also promotes lithium ion transport at the surface region of cathode. The in-situ surface modification approach simplifies the traditional post coating process, and may provide new insight to build stable and low cost Li-rich cathode for lithium-ion batteries.

Transition-metal-catalyzed asymmetric insertion of carbene into O-H bonds is a straightforward method for the synthesis of chiral alcohols and their derivatives. In recent years, a variety of chiral catalysts have been developed to achieve high enantioselective insertions of metal carbenes derived from α-diazoesters into O-H bonds of alcohols, phenols, carboxylic acids, and even water. However, there are few successful examples of the asymmetric O-H bond insertion using α-diazoketones as carbene precursors. In this paper, we report the first asymmetric O-H insertion of α-diazoketones with alcohols co-catalyzed by achiral dirhodium complexes and chiral spiro phosphoric acids. The reaction has high yields and high enantioselectivity (up to 95% ee). The present O-H bond insertion reaction provides an efficient method for the synthesis of very useful chiral α-alkoxy ketones, which are easily transformed to corresponding 1,2-diol derivatives with excellent diastereoselectivity. The density functional theory (DFT) calculation was performed to study the mechanism of the reaction. It is found that the chiral spiro phosphoric acid can promote the proton transfer process of enol intermediates generated from rhodium carbene and alcohol like chiral proton-transfer shuttle and realize enantioselectivity control accordingly. Water are likely to participate in this proton transfer step and has a remarkable effect on the enantiocontrol of the reaction. A typical procedure for the enantioselective O-H bond insertion of α-diazoketones is as follows. Powered Rh₂(TPA)₄ (2.9 mg, 0.002 mmol, 1 mol%) and chiral spiro phosphoric acid (R)-1k (3.3 mg, 0.004 mmol, 2 mol%) were introduced into an oven-dried Schlenk tube in an argon-filled glovebox. After CHCl₃ (2 mL) was injected into the Schlenk tube, the solution was stirred at 25℃ under the argon atmosphere. A solution of benzyl alcohol (21.6 mg, 0.2 mmol) and 1-diazo-1-phenylpropan-2-one (2a, 33.8 mg, 0.21 mmol) in 1 mL of CHCl₃ were then introduced into the Schlenk tube containing catalysts. The resulting mixture was stirred at 25℃ until the diazo compound 2a disappeared. After concentration in vacuo, the residue was purified by flash chromatography on silica gel (petroleum ether/ethyl acetate, V:V=15:1) to give (-)-1-(benzyloxy)-1-phenyl-propan-2-one (4a, 43.2 mg, 0.18 mmol, 90% yield) as a colorless oil.

Transition metal-catalyzed reductive carboxylation of unsaturated hydrocarbons with CO₂ is a promising and potential strategy, offering an excellent alternative access to carboxylic acids/acrylic acids. The active transition metal species could react with unsaturated hydrocarbons and CO₂ to generate the stable metallalactones or carboxylic salts. The transmetalation between reductants and metallalactones/carboxylic salts regenerates the active catalytic species. As a result, the reductive carboxylation is able to run in a catalytic mode rather than stoichiometric version. Organometal species, silanes/boranes, metal powder, methanol and hydrogens have been developed as reducing reagents in reductive carboxylation with CO₂. In this perspective, the latest advances on the transition metal-catalyzed reductive carboxylation are summarized, with particular focus on the application of reductants and related reaction mechanism at a molecular level.

Organic compounds containing trifluoromethyl (CF₃) group(s) are widely prevalent in biochemical and medicinal science. This is mainly due to the fact that the trifluoromethyl group often improves the metabolic stability and lipophilicity of biologically active compounds. The need of efficient methods for the incorporation of this group into target molecules has spurred research to discover new, practical CF₃ sources. Among various CF₃ sources, the radical trifluoromethylating reagents has provided a strong driving force for the discovery of the novel trifluoromethylation reactions, and contributed enormously to the efficient synthesis of various CF₃-containing compounds. Although a wide variety of radical CF₃ sources are now available to organic chemists, little attention has been paid to assess their trifluoromethyl radical donor abilities (TR^·DA). Moreover, the available radical reagents show a very rich and diverse reactivity. The establishment of an extensive scale to quantify their CF₃ radical donating abilities should be of great value for both the rational design of novel reagents and the judicious selection of appropriate reagent to explore new radical reactions. Herein, we present a systematic computational study of the homolytic X―CF₃ bond dissociation enthalpies of 35 radical trifluoromethylating reagents by using the SMD-M06-2X/[6-311++G(2df, 2p)-Def2-QZVPPD]//SMD-M06-2X/[6-31+G(d)-LANL2DZ] method, aiming to provide an energetic guide for estimating their trifluoromethyl radical donor abilities. A comprehensive TR^·DA scale was constructed, which covers a range from -21.5 to 95.2 kcal·mol^-1. The effects of the frequently used activators including single electron transfer reagents and halogen/chalcogen-bond donors on trifluoromethyl radical donor abilities were investigated. The results show that single electron transfer is the most efficient way to promote the CF₃ radical release. We expect that the results of this study could be highly valuable for the mechanistic understanding and the rational design of novel CF₃ sources and new radical trifluoromethylation reactions.

Rechargeable Li-air batteries have attracted intensive R&D interest as advanced power sources in recent years. This article highlights the latest advances in the design and application of porous catalytic nanomaterials for air electrodes. The characteristics of three types of catalysts including carbons, noble metals, and metal oxides are introduced, along with a perspective of future research direction of efficient oxygen reduction/evolution bifunctional cathode nanocatalysts.

Silylenes, isoelectronic with carbenes, are a kind of key intermediates in organosilicon chemistry. They possess a lone pair and an empty orbital on the silicon center, and thus could be used as donors and acceptors. Consequently, they could form complexes with various metals to support new structures and chemistry similar to both carbenes and phosphines. Iron complexes played important roles in the development of catalysts because of the inexpensive, nontoxic and sustainable characteristics.Catalytic hydroboration of alkynes presents the most atom-economic and straightforward protocol for the synthesis of vinylboranes which are indispensable intermediates for C—C coupling reactions. For the catalytic hydroboration of alkynes with iron catalysts, Enthaler’s group developed the first iron catalytic system for hydroboration of alkynes by using Fe₂(CO)₉ (A, Chart 1) as the catalyst. Almost at the same time, Thomas’s group reported the bis(imino)pyridine derived iron complexes (B) in combination with an activator for catalytic hydroboration of alkynes and alkenes. In 2017, Nishibayashi and co-workers employed an iron(II) hydride complex (C) supported by a PNP pincer ligand for catalytic E-selective hydroboration of alkynes. In 2020, Findlater et al. reported the regioselective hydroboration of alkynes and alkenes with iron complexes supported by bis(2,6-diisopropylaniline)acenaphthene ligands. However, these catalysts still suffered from limited substrate scope or harsh conditions. The development of highly selective catalysts for a wide substrate scope is still desirable. On the basis of our design on silylene ligands for iron chemistry, we are interested in the silylene-iron complexes for catalytic hydroboration reactions. In this paper, hydroborylation of terminal alkynes catalyzed by a neutral silylene-imine iron(0) dinitrogen complex D was studied. The reaction is highly regio- and stereoselective and almost exclusively gave E-hydroboration products. The optimized reaction conditions are as following: To a dried Schlenk tube were added complex D (0.006 g, 0.01 mmol), toluene (1.0 mL), alkyne (0.20 mmol), and catechol borane (0.02 g, 0.20 mmol). After the mixture was stirred at 80 ℃ for 24 h, it was cooled down to room temperature. The solvents were removed under vacuum and the residue was purified by flash chromatography on silica gel to afford the desired products.

Color-tunable luminescent supramolecular hydrogel with white-light emission is widely applied in the fields of light-emitting materials and fluorescence sensors due to their good physicochemical and biochemical properties. Using β-cyclodextrin, a class of cyclic oligosaccharide with seven D-glucose units linked by α-1,4-glucose bonds, and laponite as staring materials, we herein developed a photo-luminescent supramolecular hydrogel from laponite and pseudorotaxane that was constructed by the threading of ethylenediamine-modified β-cyclodextrins onto the poly(propylene glycol) bis(2-amiono-propylether) (PPG-NH₂) chain. The supramolecular hydrogel properties thus obtained were characterized by rheological experiments, zeta potential measurements and scanning electron microscopy (SEM). The results showed that the supramolecular hydrogel possessed satisfactory mechanical properties, negative charges and porous three-dimensional structure. Then, thioflavin T (ThT) and 4-(4-dimethylaminostyryl)-1-methylpyridinium (DASPI), two typical distorted intramolecular charge transfer (TICT) molecules with dramatically increased fluorescence when the molecules are in confined region, were selected as model substrates. Generally, ThT and DASPI had almost no fluorescent emission at an excitation wavelength of 412 nm. By comparing the normalized fluorescence emission spectrum of ThT and the UV-visible absorption spectrum of DASPI, we found that the UV-Vis absorption band of DASPI showed a good overlap with the fluorescence emission band of ThT. Therefore, the fluorescence resonance energy transfer (FRET) process would occur between ThT and DASPI in the laponite/pseudorotaxane supermolecular hydrogel phase, where ThT acted as an energy donor and DASPI acted as an energy receptor. Then the fluorescence behavior of ThT/DASPI pairs in the supramolecular hydrogel phase was investigated. The results showed, after two TICT dyes, ThT and DASPI, were introduced in the hydrogel, the efficient FRET between ThT and DASPI led to the different emission colors including white light through adjusting the ratios of dyes. The convenient preparation and tunable luminescent behaviors of this supramolecular hydrogel will open a new practical path for water-based functional soft materials.

Spinel LiNi_0.5Mn_1.5O₄ is recently considered as a promising cathode material for rechargeable Li-ion batteries, yet its large-scale application is limited due to relatively poor cycling and rate performance. Metal doping is expected to be an effective approach to improve the electrochemical performance of spinel LiNi_0.5Mn_1.5O₄. However, deeper understanding into doping effects on structural and electrochemical properties of LiNi_0.5Mn_1.5O₄ electrode materials is still ambiguous. In this work, systematic first-principles studies based on the density functional theory (DFT) have been carried out to investigate electronic and structural properties of LiM_0.125Ni_0.375Mn_1.5O₄ (where M=Cr, Fe, and Co) cathode. All computations were carried out on the basis of projector augmented wave (PAW) approach as implemented in VASP. The exchange and correlation potential was treated with the generalized gradient approximation (GGA) of Perdew and Wang (PW91). In order to take into account the strong on-site Coulomb interaction (U) presented in the localized d electrons of transition metals, the GGA-U framework was used for evaluating the exchange-correlation energy. Within this framework, the effective single parameters U_eff of 3.5, 4, 5, 5.62 and 5.96 eV were used for Cr, Fe, Mn, Co and Ni, respectively. The electron wave functions were expanded by a high cutoff of 500 eV and the total energy was converged to 10^-5 eV. The following electronic states are treated as valence electrons: Li, 2s¹2p⁰; O, 2s²2p⁴; Cr, 3d⁵4s¹; Mn, 3d⁶4s¹; Fe, 3d⁷4s¹; Co, 3d⁸4s¹; Ni, 3d⁹4s¹; Regarding the accurate calculations of total energy and electronic structure, the tetrahedron method with Blöch correction was adopted for structural relaxation and density of state (DOS) analysis. The cell parameters, volume cells, and positions of all the atoms in the primitive cell were fully relaxed until the residual Hellmann-Feynman force on each atom was less than 10^-2 eV/Â. It is found that doping a small quantity of metal M atoms into the Ni site results in a decrease in the volume variation during the lithiation/delithiation cycle (ca. 4% from lithiated phase to delithiated phase, whereas 4.7% for the undoped case). Electronic calculations suggested that transition metal doping (Cr-, Fe-, and Co-doping) would effectively improve the electronic conductivity of systems. To evaluate effects of dopants on lithium mobility, we calculated the activation energies for lithium diffusion in M-doped LiNi_0.5Mn_1.5O₄ cathode. Our calculations indicate that doping with Co can potentially reduce lithium diffusion barrier as compared to that of pristine LiNi_0.5Mn_1.5O₄ spinel.

Oxygen reduction reaction (ORR) catalysts in the cathode electrode are of crucial importance in determining the electrochemical performance of fuel cells and metal air batteries. In this work, the hybrid materials composed of MnO_x nanoparticles on reduced graphene oxide (rGO) were selectively prepared via solvo/hydrothermal process and investigated as catalysts for the ORR in alkaline solution. The synthesis involved one-step in-situ reaction of MnSO₄, KMnO₄ and graphene oxide (GO) to form MnO_x nucleus, and growth of nanosized Mn₃O₄ or MnOOH on the rGO matrix in ethanol or water. The X-ray diffraction (XRD), Raman, and FTIR spectroscopies indicated the reduction of GO and the formation of Mn₃O₄ and MnOOH phase. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the Mn₃O₄ nanoparticles or MnOOH nanorods were homogenously dispersed over the few-layer rGO sheets. The MnO_x content in the obtained MnO_x@rGO composites was determined to be approximately 48% according to the TG analysis. The electrocatalytic properties of the prepared Mn₃O₄@rGO and MnOOH@rGO were evaluated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and rotating ring-disk electrode (RRDE) techniques, and were compared with neat Mn₃O₄ and MnOOH. Among the tested samples, MnOOH@rGO exhibited superior ORR activity with a onset-potential of -0.11 V, a half-wave potential of -0.32 V and a high kinetic limiting current density (J_k) of 4.69 mA·cm^-2 at -0.6 V. Furthermore, MnOOH@rGO enabled an apparent 4-electron reduction of oxygen and showed considerable durability. The superior performance of MnOOH@rGO hydrid hybrid was attributed to the synergistic effect of rGO substrate and MnOOH nanorods and indicated its promising application as efficient ORR catalyst.

A series of Mo/beta zeolite samples with different Mo loadings were prepared via a two-step post-synthesis strategy using dealuminated Si-beta and bis(cyclopentadienyl) molybdenum dichloride (Cp₂MoCl₂) as precursors. The as-prepared samples were thoroughly characterized by a series of techniques including X-ray diffraction (XRD), the diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), temperature-programmed reduction by hydrogen (H₂-TPR), high-resolution transmission electron microscopy (HR-TEM) and scanning transmission electron microscopy (STEM), Mo the K-edge X-ray absorption near edge structure (XANES), the extended X-ray absorption fine structure (EXAFS) and Raman spectroscopy. Dioxo (Si-O)₂Mo(=O)₂ species were determined to be the dominant Mo species confined and stabilized in structure of beta zeolite. The as-prepared Mo/beta samples were applied as potential catalysts in the reaction of oxidative desulfurization (ODS) from model fuel. The effects of catalyst supports, molybdenum loadings, reaction temperature, and sulfur substrates on the ODS performance were investigated in detail, and typical kinetic analyses of dibenzothiophene (DBT) oxidation were conducted, giving an apparent activation energy value of 50.2 kJ/mol. Owing to the structure confinement, Mo species can be well stabilized within the pores and cages of beta zeolite, and the distribution of which can be regulated by controlling the anchoring sites in the zeolite support to derive well-defined isolated dioxo Mo species. 1% Mo/beta exhibited remarkable oxidative desulfurization efficiency in the removal of heterocyclic sulfur compounds like DBT from the model fuel among all the catalysts tested. Typically, 99.3% of DBT could be oxidized to the corresponding sulfone within 120 min at 333 K. Moreover, 1% Mo/beta showed good recyclability and no obvious activity loss could be observed in five recycles, in significant contrast to poor cyclic stability of traditional Mo/SiO₂ catalyst caused by the significant loss of Mo species during desulfurization reaction. Therefore, Mo/beta might be developed as efficient and stable ODS catalysts for future applications under mild reaction conditions.

Azaheterocycles have been broadly applied in the development of therapeutic agents, agrochemicals and functional material molecules. Azaheterocycles equipped with perfluoroalkyl group usually manifest superior physical and biological properties than their parent molecules, such as showing improved metabolic stability and high lipophilicity. The synthesis of perfluoroalkyl modified azaheterocycles has attracted considerable research interest in recent years. The strategy of intramolecular aminoperfluoroalkylation of alkenes, which functionalize C=C bond with an external perfluoroalkyl group and an internal amine nucleophile in one pot, provides a streamlined synthesis of perfluoroalkyl substituted azaheterocycles. This strategy has been applied by Liu, Sodeoka and other research groups in the synthesis of perfluoroalkyl substituted aziridines, pyrrolidines, lactams and pyrazolines featuring the use of pendent amine, amide, hydrazone or urea group as internal amine source. We have previously developed a copper(I)-catalyzed intramolecular aminotrifluoromethylation reaction of O-homoallyl benzimidates with Togni reagent I for the synthesis of trifluoromethyl containing chiral 1,3-oxazines using a chiral BOX ligand. However, this method is limited to aminotrifluoromethylation reaction as other perfluoroalkyl substituted hypervalent iodine reagents are not easily accessible. Herein, we report our recent research results on the synthesis of perfluoroalkyl substituted 1,3-oxazines using commercial available perfluoroalkyl iodides as perfluoroalkyl source. This intramolecular aminoperfluoroalkylation reaction proceeds selectively in the presence of Cu(OAc)₂ catalyst, 1,10-phenanthroline ligand and AgOAc additive. A broad range of O-homoallyl benzimidates and perfluoroalkyl iodides are compatible with the reaction conditions, affording perfluoroalkyl substituted 1,3-oxazines in moderate to good yields. The 1,3-oxazine product can be prepared in gram scale and readily hydrolyzed under mild conditions to give perfluoroalkyl substituted 1,3-amino alcohols. Preliminary mechanism studies revealed that this intramolecular aminoperfluoroalkylation reaction initiated with the addition of a perfluoroalkyl radical to the terminal alkene, and the subsequent functionalization with the benzimidate motif via intramolecular substitution generated 1,3-oxazine products.

Reaction of the arylimine-amidinate ligand[NNN]H (1) ([NNN]=[2-C(H)NDippC₆H₃NHC(Ph)NDipp], Dipp=2,6-i-Pr₂C₆H₃) with Ln(CH₂SiMe₃)₃(THF)₂ (Ln=Y, Sm) in n-hexane at -78℃ followed by stirring the mixture for 3 h at room temperature afforded[NNN]Ln(CH₂SiMe₃)₂ (Ln=Y, 2; Ln=Sm, 3) in 75% and 50% yields after work up. 2 and 3 have been characterized by ¹H NMR, ¹³C NMR, IR spectroscopy, elemental analysis. The molecular structure of 2 has been confirmed by X-ray analysis. Complexes 2 and 3 catalyzed the polymerization of isoprene in the presence of[Ph₃C][B(C₆F₅)₄] (1 equiv.) and AlEt₃ (10 equiv.) at 25℃. 2 converted 250 equivalents of isoprene into polyisoprene with a narrow molecular weight distribution (M_w/M_n=1.20) and a 3,4-rich microstructure (3,4-selectivity: 78%, rr=50%) in 12 h. A significant increase of 3,4-selectivity was observed in the presence of one equivalent of AlEt₃ (3,4-selectivity: 87%). When i-Bu₂AlH (10 equiv.) was used instead of AlEt₃, the catalytic activity and selectivity did not change noticeably while the resulting polyisoprenes feature a broad molecular weight distribution (M_w/M_n=2.45). When the amounts of i-Bu₂AlH decreased from 5 to 1 equivalent, a significant increase of 3,4-selectivity and number-average molecular weight have been observed while the molecular distributions became small. The catalyst is active within a wide range of temperatures from low temperature to 40℃. At 40℃, a similar selectivity (3,4-selectivity: 78%, M_w/M_n=1.43) to that found at 25℃ but the increased reaction rate has been observed. High stereo- and regioselectivity and narrow molecular weight distributions were obtained at -20℃ (3,4-selectivity: 88%, rr=52%, M_w/M_n=1.15). The samarium alkyl 3 exhibited a high activity but low selectivity (25℃, 3 h, 3,4-selectivity: 67%, M_w/M_n=1.71) compared to the yttrium alkyl 2.

Benefiting from the excellent host-guest binding capacity, p-sulfonatocalixarenes are widely used in the fabrication of versatile supramolecular assemblies in aqueous media. This review introduces the driving forces for supramolecular assembly based on the complexation of p-sulfonatocalixarenes with cationic guests and the key factors for morphology control; three usual models for supramolecular assembly involving calixarene-induced guest assembly, guest-induced calixarene assembly and calixarene-guest coassembly; and the applications in stimuli-responsive materials, drug delivery, multifunctional nanoplatform, and supramolecular catalysis.

Porous graphene material, named as MWRGO, has been prepared by microwave-assisted reduction method. Extensive characterizations indicate that graphene oxide was effectively reduced and MWRGO has a porous and disordered stacking structure. It has a special surface area of 461.6 m²/g with pore size centered at 0.67 nm. H₂ and CO₂ adsorption properties of MWRGO were investigated, showing a H₂ uptake of 0.52 wt% at 77 K and 1 atm and an absolute adsorption amount as high as 10.7 wt% at a higher pressure of 60 bar. The amount of CO₂ adsorption at 273 K and 1 atm is 7.1 wt%.

Sodium ion batteries (SIBs) have become one of candidates for post-lithium batteries due to the rich sodium resources and the similar physico-chemical properties between sodium and lithium, while the larger sodium ion radius affects the kinetic properties and ion mobility of the sodium ion batteries system, so finding the right electrode material has become the key to develop SIBs. Vanadium Disulfide (VS₂) as a typical family member of transition metal chalcogenides (TMCs) has the graphene-like layered structure and excellent electrical conductivity, which provides sufficient space for the storage of sodium ions and ensures its high performance as anode for SIBs. In this work, we used the combination of hydrothermal method and ultrasonic stripping method to prepared three different Coin-like VS₂ (VS₂-Long, VS₂-Middle, and VS₂-Short) for sodium storage research. The results show that Coin-like VS₂-Short (VS₂-S) with the lowest stacking degree can expose more active sites and has a more stable structure so that it has a high capacity of 410 mAh·g^-1 after 300 cycles at 100 mA·g^-1 and a high rate capability of 333 mAh·g^-1 even at 2000 mA·g^-1. In addition, we also studied the mechanism of vanadium disulfide as electrode material of sodium ion batteries by using the ex-situ X-ray diffraction (XRD) and transmission electron microscopy (TEM). During discharge process, sodium ion was inserted into the layer of VS₂ resulting in Na_xVS₂ at the voltage of 2.5~1.0 V, and then, Na_xVS₂ convert to sodium sulfide and vanadium between the voltage of 1.0~0.2 V, on the opposite charging process, sodium sulfide with vanadium will convert to Na_xVS₂ firstly and then vanadium disulfide will appeared again with the sodium ion deserted from the Na_xVS₂. This means that vanadium disulfide appears to be an insertion-conversion mechanism between 0.2~2.5 V.

Chemometric methods have been proved to be a powerful tool for resolution of overlapping signals. Immune algorithm (IA) is one of the chemometric approaches for analyzing multi-component GC-MS signals. The method extracts the information of the components by iteratively eliminating standard information (chromatogram or mass spectrum) from overlapping GC-MS signals. In the primary IA, however, the standard signal of each component possibly contained in the mixture must be provided by measuring the standard or by theoretical simulation. When there is difference between the measured signals of the standards and the mixture, distortion and negative values will appear in the resolved chromatograms. In order to conquer the problem, an algorithm based on an alternative iteration of least squares fitting and IA was proposed in this work. In the method, the measurement of GC-MS was achieved with a very fast temperature program to make the analytes to elute within a short retention time period, and then the chromatographic and mass spectral information of the components in the overlapping signal is calculated with the proposed algorithm. In the calculation, the algorithm takes random mass spectra of the components as the starting input, and then the information of each component is obtained with an alternating iterative process. In the iteration, the mass spectra are calculated by using the least squares fitting and the chromatographic profiles are resolved by IA. Furthermore, the non-negative and unimodality constraints are adopted in the calculation for improving the resolved results. The iteration stops when the remaining signal does not change. The feasibility of the method was validated by using a simulated GC-MS data matrix of a three-component mixture, and the practicability of the method was proved by resolving the GC-MS data of the 40-pesticide mixture. The results show that both the mass spectra and the chromatographic information of the components were extracted from the overlapping signals, and the pesticide mixture was analyzed within 10 min elution with the help of the proposed method.

During the development of multifunctional and advanced energy materials, mesoporous organic-inorganic metal phosphonate hybrids are considered as a promising candidate for environmentally friendly materials with multifunctionalities, which have attracted much attention because of the combination of superior properties from both the organic and inorganic components. They are not just physical mixtures of organic and inorganic moieties, but regarded as nanocomposites with organic and inorganic components that are intimately mixed on a molecular level. By using organically bridged polyphos-phonic acids and their derivatives (i.e. salts and esters) as coupling molecules, the homogeneous incorporation of a considerable number of organic functional groups into the hybrid framework has been realized. Furthermore, the incorporation of mesoporosity with high surface area, adjustable pore size and large pore volume could contribute to the enhanced performances in various areas. This paper systematically reviewed the synthesis principle of the mesoporous metal phosphonates including the synthesis mechanism, mesophase adjustment, pore size control, morphological design and the crystallinity enhancement. The applications of these materials in the fields of adsorption, separation, catalysis, biosensing and controlled drug release were elaborated and the further development and the perspective of the mesoporous phosphonate were expected.

Sparked by the strategy of molecular magnets, three magnetic coordination polymers, [Co₂(N₃)₄(L)_2.5]_∞ (1), [Ni₂(N₃)₃(NO₃)(L)_2.5]_∞ (2) and [Mn₂(N₃)₄(L)_2.5]_∞ (3) (L=4,4'-bis(imidazol-1-yl)biphenyl), have been synthesized by employing azide as the coupling carrier and a rod-like ligand L as the magnetic insulator. Structural analysis indicates that complexes 1～3 are iso-structural, and illustrate a 2D (4,4) layer based on unprecedented linear tetranuclear units bridged by the EO-azido ions. Their magnetic measurements revealed that complexes 1～3 all present the ferromagnetic (FM) coupling, which was due to the EO-azido linker. The corresponding exchange coupling constants have been estimated by fitting the experimental data, which confirmed the above magneto-structural correlations.

Lanthanide elements show great advantages in luminescence materials and are increasingly applied in the design of advanced functional luminescence materials due to their excellent luminescence characteristics, such as long-lived excited states, narrow emission bandwidths and large Stokes shift. Cyclodextrin, as the second generation supramolecular host molecule, is easy to be functionalized and specifically binds the luminescent guests, so it is widely used to construct supramolecular systems such as luminescent materials and fluorescence sensing probes. In this paper, based on the construction of supramolecular assemblies of lanthanide/cyclodextrin, the author reviews the recent research progress of different lanthanide/cyclodextrin luminescent materials, which will provide reference for the development of new multifunctional lanthanide luminescent materials. Finally, the scientific problems encountered by lanthanide luminescent materials are put forward, and the development direction of lanthanide/cylodextrin luminescent materials is prospected.

Dye-sensitized solar cells (DSSCs), as an emerging solar energy conversion technology, have attracted increasing attention for their ease of fabrication, low production cost, wide variety of dye structure, and high power conversion efficiency (PCE). As the critical component of DSSCs, photosensitizers play an important role in photon capturing, charge generation and separation, as well as electron injection at the semiconductor interface. Efforts on the design and synthesis of photosensitizers are thus an effective and straightforward way to tune the photovoltaic performance. In this article, three novel phenothiazine-based D-A-π-A type organic dyes (JY50~JY52) featuring benzothiadiazole units as auxiliary acceptors have been synthesized and applied in DSSCs. The introduction of auxiliary acceptor would take the advantages of the optimization of the dyes' energy levels and light absorption. To get more impressive device efficiency, 4-hexylbenzene group was decorated onto phenothiazine donor and has proved to be effective for improving the molar absorption coefficient and suppressing the charge recombination, finally resulting in the enhancement of photocurrent (J_sc) and photovoltage (Voc). In order to investigate the effect of different electron acceptor/anchoring group, benzoic acid and cyanoacrylic acid, which are widely applied in porphyrin-based dyes and metal-free organic dyes, respectively, are employed here to construct the target dyes. As we can see from the obtained photovoltaic performance data, dyes (JY50 and JY51) with benzoic acid anchor seem more beneficial to gain a higher Voc, this may be ascribed to its nearly vertical adsorption geometry on the TiO₂ interface and the resulting decrease of the charge recombination. As for dye (JY52) with cyanoacrylic acid anchor, a better J_sc value is achieved because cyanoacrylic acid endows dye an extended conjugated system and an enhanced intramolecular charge transfer. Under AM 1.5 solar light conditions, the dye JY51 with 4-hexylbenzene unit and benzoic acid acceptor exhibited the highest PCE of 7.61%, with Voc of 797 mV and J_sc of 14.21 mA·cm^-2.

Polyhedral oligosilsesquioxane (POSS) and polyoxometalate (POM) are two kinds of clusters having totally different physical and chemical properties. For instance, the POSS cluster dissolves in weakly polar solvents, such as toluene, while the POM cluster, encapsulated by tetrabutylammonium counterions, dissolves in strongly polar solvents, such as acetonitrile, meaning the strong incompatibility. Based on this reason and their fixed shape, a novel cluster-cluster hybrid molecule with a V-shaped molecular structure (POM-2POSS) was rationally designed by covalently linking the two POSS clusters on the one side of the POM cluster. In the experiment, a two-azido-containing organosilyl derivative of a Wells-Dawson-type POM cluster and a one-propargyl-containing derivative of a POSS cluster were prepared at first. Then, the cluster-cluster hybrid was successfully synthesized by Cu-catalyzed click reaction between the two azide groups in the one POM derivative and the two propargyl groups in the two POSS derivatives. The chemical structure of this hybrid molecule was carefully characterized by NMR, ESI-MS and IR. In view of their strong incompatibility and of the particular three-dimensional (3D) structure POM-2POSS was expected to be able to self-assemble into ordered supramolecular structures. In the sample preparation POM-2POSS was dissolved in acetonitrile with a concentration of 5 mg/mL, and then the solution was dropped onto silicon substrates to prepare the thin film samples, finally the thin film samples were annealed in an acetonitrile vapor for 14 d. The film on the silicon substrate was characterized by XRD. The thin film samples for TEM characterization were made at first by floating onto the water surface and then transferred onto copper mesh. The structural analyses clearly demonstrated that the hybrid molecule self-assembled into a highly ordered lamellar morphology with a 5.1 nm periodicity, smaller than those found in block copolymers with a similar molecular weight. Formation of the highly ordered morphology reflects a self-assembly process due to absence of intermolecular entanglements, while the sub-5 nm periodicity is because of the 3D structures of the two building blocks. The findings provide a new platform for understanding of the self-assembly of nano-clusters and for development of novel hybrid materials.

As one of key enzymes that catalyze the biosynthesis of branched-chain amino acids in plants and microorganisms (bacteria, fungi), ketol-acid reductoisomerase (KARI; EC 1.1.1.86) can be regarded as a promising target for designing herbicides or fungicides. Previously, we have found that N-aryl-1-cyano-1-cyclopropane carboxamides and cyclopropylformyl thioureas exhibit favorable KARI inhibitory activity and can be made further structure modification for discovery more new inhibitors. In this continuous work, a series of novel 1-cyano-1-cycloproane carboxylic acid amides containing arylaminoformyl moity 8a～8p were designed accordingly and synthesized via one-pot Ugi reaction with 1-cyano-1-cyclo- propane carboxylic acid, aryl isonitrile, aldehyde and amine as reactants. The structures of the new compounds were confirmed by ¹H NMR, ¹³C NMR, IR spectra and elemental analysis or HRMS. Meanwhile the crystal structure of 8m was reported, which provided comprehensive structure information for this kind of compounds. From a continuous assay method that following the consumption of NADPH (involved in the KARI-catalyzed reaction) at 340 nm, it was found that most of these cyclopropane diamide derivatives exhibit obvious KARI inhibitory activities and are new KARI inhibitors, among which 8a～8c, 8m, 8n and 8j possessed inhibition rate of 94%～98% at a test concentration of 200 mg/L against rice KARI, and 8m had a K_i value of (77.91±30.15) μmol/L. These new inhibitors synthesized in this paper can inhibit KARI enzyme effectively at the same level with those of N-aryl-1-cyano-1-cyclopropane carboxamides reported previously. In addition, the preliminary bioassay results also showed that several compounds exhibit significant in vitro fungicidal activities at a test concentration of 50 mg/L against Ftasarium omysporum, Cercospora arachidicola, Physalospora piricola, Alternaria solani and Gibberella sanbinetti by using the mycelium growth rate test method, and 8e and 8p, which have comparatively broad fungicidal spectrum on the whole and are comparable with the contrast Triadimefon during the present study, could be used as novel hit compounds for further structural optimization in fungicide innovations.

Recycling use is one of the energy and resource saving strategies to dispose depleted batteries, especially primary lithium batteries that employ electrode materials based on expensive and low-abundance elements. In this study, we report in detail the recycling use of discharged Li-AgVO₃ primary battery for rechargeable Li-O₂ battery. We demonstrate that the discharged Li-AgVO₃ cell, in which metallic silver nanoparticles in-situ generated in the vanadium oxide nanowires cathode efficiently catalyze the oxygen reduction/evolution reactions (ORR/OER), can be resumed as rechargeable Li-O₂ cells when they are exposed at O₂ atmosphere. By controlling the discharge depths, we obtained different cathodes that were composed of vanadium oxide nanowires and silver nanoparticles. As the electrode was discharged to a lower voltage, more silver nanoparticles with larger particle size were distributed on the surface of vanadium oxides, as a result of the sequential reduction of Ag⁺ to Ag⁰ and V⁵⁺ to V⁴⁺. Specifically, the average size of formed Ag nanoparticles was 15 nm and 70 nm at ceased discharge voltage of 2.9 V and 2.0 V, respectively, while the formation of V⁴⁺ was observed at discharge voltage lower than 2.3 V. Electrochemical tests indicated that the Li-O₂ cells assembled with the AgVO₃ cathode discharged to 2.3 V (AgVO₃-2.3) exhibited the highest specific capacity (9000 mAh·g_carbon^-1), the lowest overpotential and robust cycling performance (up to 95 cycles at the current density of 300 mA·g_carbon^-1). The remarkable electrochemical performance of the Li-O₂ battery with the AgVO₃-2.3 cathode is attributed to the optimization of amount, size and distribution of generated silver nanoparticles that contribute to high electronic conductivity and abundant active sites for the ORR/OER. A combined analysis of electrochemical impedance spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy confirmed that the AgVO₃-2.3 cathode enables the reversible formation and decomposition of Li₂O₂ with lower charge transfer resistance on discharge and charge. The results presented here would provide new insight into the promising recycling application of depleted primary Li-AgVO₃ batteries in rechargeable high-capacity Li-O₂ batteries.

Temperature-dependent near-infrared (NIR) spectroscopy has been proposed and used in the quantitative analysis of multi-component mixtures and the understanding of the interactions in solutions. Mutual factor analysis (MFA) was developed, in our previous work, to detect glucose content in aqueous solutions and serum samples using the NIR spectra measured at different temperatures. The essence of the algorithm is to extract and compare the spectral component, named as standardized signal (SS), mutually contained in the spectral data of different samples. The relative quantity of SS can be used to build the calibration model for quantitative analysis. Furthermore, the spectral information of water can be used for the analysis, because the change of the water spectrum with temperature is a reflection of the change in glucose content. In this work, serum samples with low glucose concentration were prepared and measured at the temperature range of 30~60℃ with a step of 5℃. The feasibility of MFA in the quantitative determination of low concentration samples was further studied. Serum solutions with glucose content of 1.0~15.0 mmol/L and 0.0~1.0 mmol/L were prepared, respectively. Before calculation of MFA, continuous wavelet transform (CWT) was used to improve the resolution of the spectra. The results show that MFA can achieve an accurate quantification of the glucose content. The linear correlation coefficients (R) of the calibration models between the relative quantity of SS and the concentration of glucose are 0.9923 and 0.9895, respectively, and the root-mean-squared error of prediction (RMSEP) are 0.35 and 0.07 mmol/L, respectively. The relative error of predicted concentration of samples in the validation set obtained from the calibration model of samples with a concentration of 1.0~15.0 mmol/L are in the range of -12.00%~5.64%, which are in a reasonable level for clinical uses. Temperature-dependent NIR spectroscopy combined with MFA may be a potential way for detecting the micro-content components in complex aqueous systems.

Temperature dependent near-infrared (NIR) spectroscopy has been developed for structural analyses, especially for the study of hydrogen bonding, due to the distinct influence of temperature on both intra-and inter-molecular interactions. In this work, the hydrogen bonding of primary aliphatic amines (amylamine, hexylamine and heptylamine) were studied using the NIR spectra measured from 25 to 80℃ with a step of 5℃. Continuous wavelet transform (CWT) was applied to enhance the resolution of the NIR spectra, and independent component analysis (ICA) was adopted for analyzing the temperature effect. High resolution spectra were obtained by CWT, from which the peaks of free and hydrogen-bonded NH groups can be identified. The results obtained by ICA show that three independent components (ICs) can be obtained, corresponding to the spectral information of the free, linearly and cyclically hydrogen-bonded NH groups, respectively. Therefore, with the reconstructed spectra from the three ICs, the variation of the three forms of NH groups with temperature can be analyzed. When temperature increases, the hydrogen-bonded NH groups transform into the free form, and the cyclic form dissociates through the linear form. Furthermore, NIR spectra of the amines in carbon tetrachloride (CCl₄) solution were measured at 25℃ in the concentration range of 0.1~1.0 mol/L. The three ICs can also be obtained by ICA from the spectra after CWT. From the variation of the ICs with concentration, it was shown that NH groups in the amines prefer to be linearly aggregated at low concentration, but the cyclic aggregation increases with the increase of concentration. In addition, a comparison was performed on the results obtained by ICA from the spectra of the three amines measured at different temperatures. The result shows that there is no obvious difference for the temperature effect of the three amines, the variation of the three forms of NH groups with temperature, however, is different. With the increase of the carbon chain length, the variation of free and cyclically hydrogen-bonded NH group slows down, but there is a slight increase for the change rate of linearly hydrogen-bonded NH group. Therefore, temperature dependent near-infrared (NIR) spectroscopy may provide a new tool for studying the hydrogen bonding in liquid and solution samples with the help of chemometric calculations. The method may be promising for analyzing the complicated interactions in bio-systems, particularly the hydrogen bonding or inter-and intra-molecular interactions.