Cyclodextrins (CDs) are a family of macrocyclic oligosaccharides composed of α-1,4-linked D-glucopyranose units. The most commonly used CDs are α-, β-, and γ-CD, which consist of 6, 7, and 8 D-glucose units, respectively. They possess a relative hydrophobic inner cavity and a hydrophilic outer surface and can form inclusion complexes with various small molecules, metal ions and polymers, tailoring the physicochemical property of the guests, and thus have been widely used in the fields of pharmacy, food, chemistry, chromatography, catalysis, biotechnology, agriculture, cosmetics, hygiene, medicine, textiles and the environment, etc. However, it is difficult to manipulate the native CDs in some specific applications, they are crystallized solid and soluble in water but insoluble in most organic solvents. CD polymers (CDPs), such as crosslinked CDs or CD based hydrogels with various crosslinkers by chemical reactions, and CD based supramolecular polymers formed by physical interactions, can achieve the integration effect and synergy effect of CDs, crosslinkers and guest polymers, not only possessing the inclusion capacity of CDs, but also endowing CDs with other properties introduced by crosslinkers. The CDPs can be easily manipulated and they exhibit unique features that native CDs are lack of. Hence, the design, synthesis and applications of CDPs have attracted broad interests in recent years. This review focuses on the recent progress in CDPs, and different types of CDPs are identified and classified based on the structures and functions, namely CD based polyrotaxane, grafted CDs, crosslinked CDs and linear CDs, etc. Besides, the synthetic methodologies of CDPs are highlighted. Particular attention is paid to the breakthrough on the CDPs in the past five years, and their applications in biomedicine, such as drug delivery, gene delivery, target delivery, controlled release and cell imaging are discussed in detail. The typical applications in other fields such as absorption, environment remediation, thermal insulation, catalysis and slid-ring gels are also discussed in brief. Finally, the review provides brief summary and prospect of CDPs.

Optically pure alkylnitriles are important structural motifs found in agrochemicals, pharmaceuticals, and natural products, which can be further transferred to acids, amines and amides. Direct asymmetric cyanation of sp ³ C—H bonds represents the most efficient synthetic pathway to these optically pure alkylnitriles. However, selective functionalization of sp ³ C—H bonds remains a crucial issue due to the inertness of sp ³ C—H bonds as well as the difficulties in the control of stereo- and regioselectivity. Inspired by enzymatic oxygenases and halogenases, such as cytochrome P450 and nonheme iron enzymes, the radical-based C—H functionalization has received much attention, which was initiated with a hydrogen atom transfer (HAT) process. Recently, numerous reports have been disclosed for the highly efficient functionalization of C—H bonds with an intramolecular HAT process as a key step to govern the reactivity and site selectivity. Our group has developed a copper-catalyzed radical relay process for the enantioselective cyanation and arylation of benzylic C—H bonds using TMSCN and ArB(OH)₂ as nucleophiles respectively. Mechanistic studies indicated that a benzylic radical generated via a radical replay process can be trapped by a reactive chiral copper(II) cyanide enantioselectively, delivering optically pure benzyl nitriles efficiently. Herein, we communicate the catalytic asymmetric cyanation of remote C—H bonds by merging photoredox catalysis with copper catalysis. This reaction proceeds under mild reaction conditions and exhibits good functional group compatibility as well as wide substrates scope. Additionally, the nitrile group was further reduced to amide under hydrogen atmosphere. This reaction provides an efficient pathway to synthesize chiral δ-cyano alcohols and 1,6-amino alcohols. The general procedure is as following: in a dried sealed tube, substrate 1 (0.2 mmol, 1.0 equiv.), Cu(CH₃CN)₄PF₆ (0.01 mmol, 5 mol%), L (0.015 mmol, 7.5 mol%) and Ir(ppy)₃ (0.002 mmol, 1 mol%) were dissolved in dichloromethane (4.0 mL) under N₂ atmosphere, and stirred for 30 min. Then, TMSCN (50 μL, 0.4 mmol, 2 equiv.) was added slowly under N₂ atmosphere. The tube was sealed with a Teflon-lined cap, and the mixture was stirred under the irradiation of blue LED for 1~7 d. The reaction mixture was diluted with dichloromethane, filtered through a short pad of celite. A solution of TBAF (3 equiv.) and HOAc (3 equiv.) was added to the filtration. The mixture was stirred for 5 min and then washed with water (3×10 mL) and dried over anhydrous Na₂SO₄. After filtration and concentration, the residue was purified by silica gel chromatography (eluent: petroleum ether/ethyl acetate) to afford target product.

Molecular electronics is an interdisciplinary science that mainly studies the charge transport through molecules and its main goal is to fabricate molecular devices with electrical functionalities. In the state-of-art of molecular electronics, the research paradigm is to fabricate electrodes pair with nanometer-sized separation and construct the molecular junction through the assembly of target molecules with the electrodes pair. With this framework, the target molecule can be integrated to the macroscopic measurement circuit. DNA is one of the most significant biomolecules in natural sciences. It had drawn great attentions in biomedicine because of the carried genetic instructions. In molecular electronics, DNA also had attracted much interest due to the distinct structure and its capability of long-range charge transport. Nevertheless, in the early stage of molecular electronics, the probe molecules were limited to those with simple structures and short lengths. In recent years, molecular electronics had witnessed a rapid progress due to the developments in micro/nano-fabrication and the detection for weak current signal. Specifically, it includes the improvements in the success rate, efficiency, and stability of the fabricated molecular device. Benefiting from that, the probe molecules had been extended to a number of complex compounds like DNA. We give a brief introduction to the recent progress in the fabrication of DNA molecular junctions and the studies on the corresponding charge transport, most of which were made by using the research paradigm of fabricating electrodes pair with nanometer-sized separation. According to the fabrication methods that employed, these advances were introduced in two classes. One is that made by the as-called break junction methods, which include STM-break junction, conductive AFM and mechanically controllable break junction. The other is that made by the as-called cutting methods, which include cutting of carbon nanotube, graphene and silicon nanowire. We summarize the historical development of these methods and give a comparison between them. We also introduce some representative research on the charge transport through DNA molecular junction, and discuss the distinct features of DNA in electrical properties compared to the conventional small molecules. To conclude, we give a prospect on the future development of the studies on charge transport through DNA molecular junction.

Surgical sutures, staples and clips have been widely used for wound closure, tissue reconstruction and tissue adhesives are one of the versatile alternatives especially for friable tissues. Some synthetic and semisynthetic tissue adhesives are available elsewhere. However, there are some drawbacks, such as poor adhesion on wet substrates and potential toxicity, for the reported tissue adhesives. Fibrin glues as biological tissue adhesives are effective hemostatic agents while presenting relatively weak tensile and adhesion strengths and being expensive. Biomimetic adhesives as tissue adhesives, hemostatic agents, or tissue sealants have attracted great attention for clinical operations in last three decades. However, engineering of bio-adhesive materials with good water resistance, high adhesive strength, and good biocompatibility and multi-functionality remains a challenge for tissue healing. Since the first report of mussel-inspired surface chemistry for functional coatings of polydopamine by the Messersmith group in 2007, materials containing plenty of phenolic hydroxyl groups have been widely used in medical applications, food, cosmetics, water treatment and so on, due to the antioxidant, antibacterial, and anti-inflammatory effects of polyphenols. Polyphenol-based hydrogel is an ideal bio-adhesive material due to its good tissue adhesion even on wet substrates, hemostatic and antimicrobial capabilities. Moreover, these hydrogels with porous structures have similar physiochemical properties to that of natural extracellular matrix and different shapes from nanometer to centimeter scales can be remolded to seal irregular defects on tissues. In this review, we report the recent progress of the engineering of polyphenol-synthetic polymer hydrogels, polyphenol-biomacromolecule hydrogels, polyphenol-inorganic nanocomposite hydrogels, and polydopamine nanoparticle composite hydrogels, as well as their applications of tissue adhesives, hemostasis, antimicrobials for wound closure and tissue regeneration. The challenges as well as prospects for future development of polyphenol-based tissue adhesives, sealants, hemostatic agents are also summarized and discussed, which is helpful to promote the next generation of tissue adhesives for biomedical applications.

Since the introduction of perovskite solar cells in 2009, perovskite solar cells have developed rapidly due to their low-cost and high theoretical photoelectric conversion efficiency. Among them, the inverted structure of perovskite solar cells has received more and more attention due to its good stability and low hysteresis effect. Since its inception in 2013, its photoelectric conversion efficiency has rapidly increased from the initial 3.9% to 21.5%. However, compared with the traditional upright structure perovskite solar cells, there is still a gap in the photoelectric conversion efficiency of inverted perovskite solar cells. Due to the nature of the organic materials used, perovskites are more severely affected by moisture in the air environment. They are heavily dependent on nitrogen protection during device manufacturing. In the future, if perovskite solar cells are put into production, the fully enclosed waterless environment will obviously increase the production costs. At the same time, the development of large-area preparation technology is still a difficult problem to be solved. The development of inverted perovskite solar cells, the selection of carrier transport materials, interface optimization, and the development of flexible devices are systematically reviewed in this paper. For example, PEDOT:PSS was doped by GeO₂ and DMSO, and PEDOT:PSS was modified by MoO₃ and GO to improve its work function, acidity and hygroscopicity. A NiO_x dense layer is usually doped with Mg ²⁺, Li ⁺ and Cs ⁴⁺ to increase its conductivity, which can be prepared by different methods such as magnetron sputtering and sol-gel method. The PCBM interface is modified by C₆₀, BCP, LiF etc., to enhance its ohmic contact with the metal counter electrode. And the PCBM is doped by graphene, CoSe, SnO₂ etc., to reduce the charge recombination caused by the interfacial resistance and the defects of the perovskite film. This paper would provide a way to obtain a high efficiency inverted perovskite solar cells by structure and material optimization. And it also give insights into the general rules for preparing large area and flexible devices.

The production and transformation of alkynes occupys an important position in organic synthetic chemistry. Within this realm, propargylic functionalization of alkynes is a feasible way towards this purpose. Especially, the propargylic functionalization via radical pathways has flourished in the last decade, which is believed to be a significant complement to the classic metal-catalyzed propargylation reaction involving cationic intermediates. According to the reaction modes, these advancements will be highlighted by classifying into four types. The first one is the propargylic functionalization reactions involving propargylic radicals. Generally, propargylic radicals can be generated through single electron reduction of alkyne substrates by low-valence metal catalysts or excited state of photocatalysts, then participated in the following cross-coupling reactions to achieve alkyne products. In this part, asymmetric variants have been also well developed. The second one is the preparation of allene compounds through the allenyl radical pathway. For these processes, propargylic radicals can isomerize to allenyl radicals, which can participate in the copper- or nickel-catalyzed coupling reaction to produce significant allene compounds. The third one is the dehydrative alkylation reaction of propargyl alcohols that involve propargylic radical intermediates, too. Such radical intermediates can be further oxidized to propargylic cation intermediates, followed by a deprotonation to form substituted 1,3-enyne compounds. The forth one is the synthesis of vinylic alkoxyamines through a propargylic radical route. Initially, propargyl alcohols can be converted to propargylic radical species by the joint action of copper catalysts and TEMPO. The generated propargylic radical species can be captured by TEMPO to form vinylic alkoxyamines. Finally, an outlook on the radical propargylic functionalizations will be provided at the end of this review.

Catalytic synthesis of organic sulfinamides has great significance and value in organic synthesis, material science, and bioscience. Traditional synthetic methods for sulfinamides are often confronted with various challenges, such as tedious reaction steps, harsh reaction conditions. Direct activation of S—H and N—H bonds to synthesis sulfinamides is the most effective and atomic economic way, which can realize the N—S bonds construction without pre-functionalization of the substrates. To establish a versatile and efficient technology for such reaction, an electrochemical cross coupling hydrogen evolution (CCHE) reaction, which is often used as an environmentally friendly and efficient way to construct new bonds, for synthesis of sulfinamides has been successfully developed by using thiols and amines as the easily available and inexpensive substrates. A series of sulfinamides were prepared with excellent yields and good compatibility of functional groups under extremely mild reaction conditions. Experimental results showed that sulfenamides, which were constructed as intermediate products via radical pathway, were further oxidized to sulfinamides. H₂ ¹⁸O labeling experiment confirmed that the oxygen of sulfinyl group comes from the trace water in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP). In addition, tetrabutylammonium iodide (TBAI) played important dual roles of intermediate and electrolyte in this reaction system. The typical procedure is as follows: A 20 mL oven-dried reaction vital equipped with a magnetic stir bar was charged with thiol 1 (0.2 mmol), amine 2 (0.3 mmol) and TBAI (0.05 mol/L) in HFIP (5 mL), and exhausted via puncture needle for 15 minutes with argon. The mixture was then electrolysed with carbon foam plate (anode) and platinum plate (cathode) as the electrodes in an undivided cell for 6 hours in 10 mA constant current at room temperature. After the reaction, the mixture was evaporated under reduced pressure to remove the solvent and the residue was purified by chromatography on silica gel to get the desired sulfinamide 3.

CO₂ is an ideal C1 source in chemical transformations. It is of great significance to utilize CO₂ in chemical conversion to synthesize high value-added compounds, including carboxylic acids and carbonyl-containing heterocycles. On the other hand, the difunctionalization of olefins is an important organic reaction, which can efficiently convert easily available olefins into important compounds with structural diversity. However, due to the low reactivity of CO₂ and the difficulty in controlling the selectivity, the difunctionalization of olefins with CO₂ is highly challenging. Recently, the significant progress of radical chemistry has provided new strategies and promoted the development of novel transformations in this field. This Perspective summarizes the recent progress of the radical-type difunctionalization of olefins with CO₂, including the oxy-alkylation, carbocarboxylation, silacarboxylation, thiocarboxylation, and dicarboxylation of alkenes with CO₂. At the same time, we also highlight the mechanism with radicals and four kinds of pathways are proposed: (1) Free radicals attack olefins to form new carbon radical intermediates. The radicals are then oxidized to form carbocations, which are further captured by carbonates or carbamates. It is also possible for direct C—O bonding reaction or sequent C—I and C—O bonds formation. (2) The new carbon radical intermediates, in-situ generated through attack of alkenes with radicals, are reduced via single electron transfer into carbanions, which could attack CO₂ to form C—C bonds. (3) CO₂ is reduced into CO₂ radical anions in the highly reductive reaction conditions. Once generated, the CO₂ radical anions might attack olefins to form carboxylate bearing more stable carbon radical intermediates (such as benzylic ones) and further form C—C bonds or carbon-heteroatom bonds. (4) Olefins are reduced via single electron transfer into alkenyl free radical anions in the highly reductive reaction conditions. These anions may attack CO₂ to form carboxylate bearing carbon radical intermediates and are further reduced to generate carbanions. Finally they may attack another CO₂ to form succinic acid derivatives. We point out the challenges and predict the future development in the field, including the more challenging substrates, more reaction types, better selectivities, and deeper mechanistic understanding.

Nanopore technology are being developed for large areas in life science, not only in DNA sequencing and protein sequencing, but also in biomolecule detection, bio-interaction measurement and drug screening. Aerolysin is regarded as new powerful tool for oligonucleotide sensing and peptide sensing due to its high charged pore lumen. Applied a transmembrane potential with a pair of Ag/AgCl electrodes, the negatively charged oligonucleotides are driven into the aerolysin nanopore, inducing a series of ionic current blockages, which could distinguish the oligonucleotides with different length or single base variation. However, due to the lack of high-resolution structure of aerolysin nanopore, the mechanism of its high sensing capability is not clear, limiting the further applications of aerolysin. Recently, we presented two sensing regions inside aerolysin, R1 (near R220) and R2 (near K238), having huge influences on oligonucleotide sensing. Especially, the R1 is responsible for distinguished all 4 bases and 2 modified based in the mixture. However, the detailed mechanism of synergistic effect for these two regions in detection of single nucleotides is still unclear. Here, we use dA₁₄-4-X, dA₁₄-11-X, dA₁₄-4-X-11-X (X=C, T, G) as probes to investigate the effects of base types on the sensing ability of R1 and R2. The results show that the A, C or T in R2 region did not change the sensing ability of R1 region, while G in R2 would hinder the base discrimination in R1 region. This may be caused by the large volume of G that would nearly fully occupy the R2 region and the stronger non-covalent interaction between G and R2 region, resulting in determining the residual current of the whole nanopore. Moreover, we evaluated the interaction between different bases with the sensing region. The results show that the interaction is independent with the volume of the bases, which is ordered by A>G>C>T, suggesting the interaction inside the aerolysin lumen is a considerable factor for its sensing capability. These results would guide us to directly design the mutant Aerolysin nanopore that aims for DNA sequencing and peptide sequencing.

Allylic substitutions catalyzed by transition metals are important and practical reactions, which can construct carbon-carbon bonds and carbon-heteroatom bonds efficiently and stereoselectively. Various transition metal catalysts, such as Pd, Ir, Cu, Ni, Rh and Ru, have been widely used in this reaction. To date, various “soft”, or stabilized nucleophiles (pKa<25), including malonates, acetoacetates and enolates, have been used in allylic substitutions. Conversely, the high reactivity of “hard”, or non-stabilized alkyl nucleophiles (pKa>25) has limited their utility in catalytic processes and their compatibility with functional groups. Visible light photoredox catalysis has been widely used in organic synthesis because it can generate high reactive intermediates, such as free radicals and radical ions, under mild conditions using green and clean energy, and has gradually developed into an important synthetic tool. Furthermore, merging photoredox catalysis with transition metal catalysts has become a popular strategy for expanding the synthetic utility of visible-light photocatalysis, and has led to the discovery of novel reaction modes. Due to the high activity of the intermediates in photoredox catalysis, the selectivity of these reactions, especially stereoselectivity, is still a challenge. In view of the importance of allyl substitutions, the allyl substitution co-catalyzed by transition metals and photoredox has attracted the interest of chemists. The synergistic strategy can realize allylic substitutions which are difficult to be achieved by single transition metal catalysis. The regioselectivity and stereoselectivity of these reactions also show different characteristics. It is expected to become an important complement to allylic substitution catalyzed by single metal. In this review, recent advances on allylic substitution co-catalyzed by different transition metals and photoredox are summarized. Meanwhile, the mechanism of representative transformations will be briefly introduced and the prospective in this area will be given.

photocatalytic pollutant degradation and the synthesis of chemical fuels or other high value-added products via photocatalysis have drawn plenty of attentions in green chemistry and renewable energy research. In recent years, metal-halide perovskites with superior photoelectric properties are successfully utilized into high-efficiency photocatalytic reactions in addition to conventional metal oxide semiconductor materials. In this paper, we reviewed the recent advances of metal-halide perovskite based photocatalyst, especially lead-halide perovskites in photocatalytic hydrogen production, photocatalytic degradation and CO₂ reduction. The reaction mechanisms and key challenges for metal halide perovskites photocatalyst are discussed and we prospect the further development of highly efficient and stable metal halide perovskite photocatalysis in the future.

During the past decade, transition metal-catalyzed dehydrogenative cross-couplings have emerged as an attractive strategy in synthetic chemistry due to its high step- and atom-economy as well as the less functionalized coupling partners. However, such reactions have to always use stoichiometric amount of sacrificial oxidants such as peroxides, high-valent metals (Cu salts, Ag salts, etc.), or iodine(III) oxidants, thereby leading to possible generation of toxic wastes and making the process less desirable from a green chemistry perspective. The recently developed photocatalytic CCHE (cross-coupling hydrogen-evolution) reactions are a conceptually new type of reactions enabled by combination of photo-redox catalysis and proton reduction catalysis, wherein the photocatalyst uses light energy as the driving force for the cross-coupling and the hydrogen evolution catalyst may capture electrons and protons from the substrates or reaction intermediates to produce molecular hydrogen (H₂). Thus, without use of any sacrificial oxidant and under mild conditions, the dual catalyst system may afford cross-coupling products with excellent yields and an equivalent amount of H₂ as the sole byproduct. This kind of cross-coupling delivers a greener synthetic strategy and is particularly useful for reactions that involve species sensitive to traditional oxidants. In CCHE reactions, the raw materials are directly converted into products and hydrogen, the reactions are highly atom economy, environmentally friendly, and have attractive potential industrial application prospects. In this review, recent dramatic developments of photocatalytic and electrochemical CCHE reactions are discussed via the most prominent mechanistic pathways, the types of C-C bond, C-X (heteroatom) bond, or X-X bond formations and specific reaction classes.

Imines and the intermediate methylamine by the aldimine condensation of primary amines with aldehydes have a potential application in the field of pharmacy, life science, catalysis, material science, etc. In this reaction, the hydrogen transfer in the dehydration step normally prefers the pathway via a water bridge in aqueous solution or a directly dehydration in organic solvent. It is a different mechanism for the aldimine condensation of amine owning neighbouring nitrogenous heterocycle. Herein we investigated the mechanism of aldimine condensation of primary amine containing nitrogenous heterocycle with aldehyde in dichloromethane under acidic conditions using density functional theory (DFT) at ωB97X-D/6-31++G(d,p) level, the calculated results show that compared with specific acid catalysis, the heterocyclic nitrogen with stronger basicity is easier to be protonated than the oxygen of carbonyl group. The whole reaction proceeds two hydrogen transfer steps via nitrogen bridge owning an energy span of 13.08 kcal/mol. The rate-determing step is the second hydrogen transfer step. In each step the heterocyclic nitrogen is a bridge to assist the hydrogen transfer, which could reduce the free energy barrier of the aldimine condensation. It is unfavorable for the reaction pathway via directly hydrogen transfer with a four-membered ring transition state owning a free energy barrier of 32.73 kcal/mol, and the reaction pathway via a water bridge is not located. Meanwhile, the energy barriers increased for systems in which the N atom in heterocycle of primary amine is replaced by P/As atoms. The rate-determining step changes from the second hydrogen transfer step for N system to the first hydrogen transfer step for As system. The position effect of adjacent nitrogen atom is also investigated. The γ position owns the highest reactivity of the aldimine condensation, which implies that the ring strain plays an important role in the aldimine condensation of primary amine containing nitrogenous heterocycle with aldehyde. This theoretical study may provide insights to unveil the nature of aldimine condensation of aldehyde and primary amine owning nitrogeneous heterocycle.

P-Chiral phosphine oxides are a class of privileged structures, which have important applications in the field of medicinal chemistry, organic synthesis, life and material science. Recent years have witnessed significant progress in the catalytic asymmetric construction of such scaffolds. These advances are summarized in this review according to the following three major strategies:desymmetrization of prochiral tertiary phosphine oxides, (dynamic) kinetic resolution of tertiary phosphine oxides, and catalytic asymmetric reactions involving secondary phosphine oxides, and discusses the possible reaction mechanism, the advantage and disadvantage of each type of reactions, which would provide reference and inspiration for the researchers engaged in organic synthesis and organic phosphorus chemistry.

In recent years, the efficiency of perovskite solar cells has developed rapidly, but its stability is limited by the influence of heat, light and water. All-inorganic perovskite formed by inorganic cations instead of organic cations shows improved thermal stability, high light absorption and adjustable band gap. The photoelectric conversion efficiency of all-inorganic perovskite solar cells has been improved to 19.03% at present. Among them, CsPbI₃ perovskite solar cells have good photoelectric performance but poor stability, while CsPbBr₃ perovskite solar cells have excellent stability but poor photoelectric performance of devices. In this paper, the influence of preparation method, film doping and interface modification on the stability of inorganic perovskite solar cells is systematically summarized. The reasons behind the instability of inorganic perovskite and the improvement methods are emphatically analyzed. In conclusion, improving the stability of inorganic perovskite light absorbing materials by film doping, surface passivation and morphology control such as low dimensional materials preparation can effectively improve the stability of the overall device, which provides the basis for further commercialization. In addition, it is of great significance to study the theory of charge transfer and recombination and establish a complete theoretical system for improving the performance and stability of the device. At present, most of perovskite contains harmful elements Pb. How to replace Pb and find new materials applied in perovskite solar cells is also the future development trend. In a word, as a new type of solar cell, inorganic perovskite solar cell is expected to contribute to the photovoltaic development of the future society.

Hantzsch Esters were first synthesized by Arthur Rudolf Hantzsch in 1881, and widely used in pharmaceutical chemistry. The application of Hantsch Esters in organic synthesis in the early time was mainly focused on the dehydrogenation of 1,4-dihydrogen pyridines (DHPs) in the synthesis of functional pyridines. In 1955, Mauzerall and Westheimer found that Malachite Green could be reduced by Hantzsch Esters to generate the hydrogenated product. Then these DHPs were extensively used as a reductant for decades due to their electron and hydrogen donating properties. In recent years, scientist found that C—C bond cleavage at 4-position of 4-substituted Hantzsch Esters would lead alkyl transfer, and the alkylation process was a radical process. With the rapid development of free radical chemistry, various alkylation reactions using 4-substituted Hantzsch Esters as alkylation reagent have been developed, such as addition reactions of imines and alkenes; cross-coupling reactions with aryl halides; substitution reactions with functional aromatics; Tsuji-Trost reaction; radical insertion with sulfur dioxide; and asymmetric alkylation etc. The advantages in alkylation transfer by using 4-substituted Hantzsch Esters as alkyl source in the past five years were witnessed dramatically: (1) Highly toxic alkyl metal reagents could be avoided in the alkylation reactions; (2) Compared with the moisture sensitivity of alkyl metal reagents Hantzsch Esters are easily handling; (3) 1,4-Dihydrogen pyridines (DHPs) are biologically-inspired model molecular of reduced nicotinamide adenine dinucleotide (NADH), which would expand the application in biosynthesis. A brief summary in this field is presented in this review, and the advances are classified according to different reaction types. Although these creativity works were developed, there are still some challenges: (1) Could aromatic groups at 4-position of 4-substituted Hantzsch Esters serve as arylation reagents? (2) How to recover the rest pyridine part of Hantzsch Esters after alkylation; (3) New type reactions need to be developed for the asymmetric synthesis.

Transition metal-catalyzed direct C-H functionalization is one of the most efficient and powerful tools for the rapid synthesis of organic molecules. The use of functional groups in the molecules or covalently attached coordinating groups as directing groups has been realized as a major strategy to control the selectivity. Noncovalent interactions are of great importance in the field of molecular biology, supramolecular chemistry, material science and drug discovery. More recently, the use of well-designed ligands to enable the site-selective C-H functionalization via noncovalent interactions has emerged as a highly promising yet relatively less explored strategy. In this perspective, recent advances in this cutting-edge area are summarized. The perspective was classified into four sections according to the type of noncovalent interactions, including hydrogen bonding, ion pair, Lewis acid-base interaction and electrostatic interaction. Emphasis is placed on the mode of noncovalent interactions among the transition metals, ligands and substrates. The limitation of current research and the prospect of future work will also be discussed. We anticipate that this strategy might become a promising complementary strategy to control the positional selectivity in C-H functionalization reactions.

The intramolecular aromatic ring systems migration reactions, namely Smiles rearrangement is a powerful method for (hetero)aryl group functionalization. It can be employed as a complementary strategy to arene functionalization, and has found its broad applications in synthetic chemistry. After the initial documentation in 1894 this chemistry was intensively investigated by Smiles. In its classical pathway, the migration of aromatic ring system takes place ipso nucleophilic substitution. Accordingly, the migrating (hetero)aryl groups are highly electronic and steric-dependent. Moreover, as new reaction modes reported, advances have been made in the areas for arene C—C, C—N and C—O bond formation and radical triggered Smiles rearrangement has also enriched migrating units. Recently, there has been a rapid growth in the transformation induced by visible-light photocatalysis. Harnessing visible light as the energy source for chemical reactions usually serves as an environmentally benign alternative in comparison with classical radical pathway. Furthermore, photoredox-induced rearrangement represents a valuable and efficient approach for facilitating both the radical-based bond-cleaving and bond-forming events in a single step. It has become an effective tool for both synthesis and late stage modification of bio-active molecules. The last five years has witnessed many important advances in exploring photo-induced Smiles reactions, which make this classic reaction regained its attention. Significant progress has been made for expediting the generation of N-centered, C-centered and O-centered from a variety of precursors before single electron transfer rearrangement. This powerful synthetic platform for efficient promotes (hetero) aromatic group construction under mild reaction conditions, and has become a useful method for the synthesis and late stage functionalization of pharmaceutically interest products. In this perspective, we focus on visible light induced Smiles chemistry, which the major breakthroughs are classified based on migrating-induced radical species, and their synthetic applications are discussed briefly.

Aryl halides are key building blocks in organic synthesis for the construction of valuable natural products, medicinal and agricultural chemicals via transition metal-catalyzed coupling or substitution reactions. Halogenation is one of the most fundamental and important reactions in organic synthesis. Electrochemical transition-metal-catalyzed C—H functionalization has emerged as a powerful tool for molecular synthesis with the prospect of avoiding the use of costly and toxic oxidants or reductants, thereby reducing the footprint of undesirable, toxic byproducts. The palladium-catalyzed electrochemical C—H chlorination of benzamide derivatives directed by PIP amine directing group under divided cells has been demonstrated, in which readily available inorganic halides salts serve as halogen sources. The reaction features a broad substrate scope, high functional group tolerance, and compatibility of thiophene substrates. This reaction could be conducted on a gram scale, which is important for future application. Additionally, the sequential bromination and chlorination of C(sp ²)—H bond constructs highly functionalized aromatic carboxylic acid derivatives. The typical procedure is as follows: The electrolysis was carried out in an H-type divided cell (anion-exchange membrane), with a RVC anode (10 mm×10 mm×12 mm) and a platinum cathode (10 mm×10 mm×0.2 mm). The anodic chamber was charged with Pd(OAc)₂ (5.6 mg, 0.025 mmol, 10 mol%) and benzamide derivative (0.25 mmol, 1.0 equiv.) and dissolved in DMF (10 mL). LiCl (847.8 mg, 20.0 mmol) was added in the cathodic chamber and dissolved in water (10 mL). Then the reaction mixture was electrolyzed under a constant current of 5 mA at 90 ℃ until the complete consumption of the starting material as monitored by TLC or ¹H NMR. After the reaction, EtOAc (50 mL) was added to dilute the mixture and then washed with water (20 mL×3) and then with brine (20 mL). The organic fraction was dried over Na₂SO₄ and concentrated. The resulting residue was purified by silica gel flash chromatography to give the chlorination product.

Near infrared II (NIR Ⅱ, 1000~1700 nm) biological imaging, as a new developing optical imaging technology in recent years, has longer fluorescence wavelength compared with the traditional near infrared I (NIR I, 750~900 nm) and visible light (Vis, 400~750 nm) imaging. Due to the longer emission wavelength, weaker interference by light scattering and tissue autofluorescence, result in higher temporal and spatial resolution with deeper tissue penetration. This technology is more suitable for in vivo imaging in situ. In this review, we mainly introduced research progress on NIR II instrument technology for in vivo imaging, and summarized its major features. Finally, we provided a prospect that the development of chemical materials, optoelectronic instruments, and multi-modal technologies can promote NIR II technology innovation, which is expected to be widely and deeply applied in clinical transformation.

Precisely modulating the structure of nanoparticles in a controlled manner is still a challenging and inspiring topic. Although the single or few-metal atom tailoring of gold nanoparticles has been reported, local structural replacement involving over three net metal atoms (module replacement, MR) has not been hitherto achieved. Herein, we report the synthesis of cyclohexanethiolated metal nanoclusters (NCs) Au₄₈(CHT)₂₆ and their MR by a so-called pseudo-anti-galvanic reaction (AGR) process. The MR product Au₃₇(CHT)₂₃ shares a similar Au₃₁(CHT)₁₂ unit with its predecessor Au₄₈(CHT)₂₆; however, it differs from its predecessor in the remaining section (Au₆(CHT)₁₁ vs. Au₁₆(CHT)₁₄), as revealed by single-crystal X-ray crystallography (SCXC). Interestingly, the MR inhibits the photothermy but enhances the emission of Au₄₈(CHT)₂₆ NCs, which might endow the as-obtained NC better potential for bi(multiple)-functional application. The counter effects of the MR on the emission and photothermy indicate that photoluminescence and photothermy can be at least partly converted into each other, which has some important implications for the understanding of their interaction.

Organic solar cells have been developing quite rapidly in the past two decades. Tang fabricated the first organic solar cell with planar heterojunction in 1986, while the power conversion efficiency (PCE) was only 1%. The PCE of single-junction organic solar cell has increased to over 17% in 2019. However, the single-junction solar cells are limited in performance by the severe energy loss. Tandem organic solar cells that use an interconnecting layer connecting two sub-cells provide the possibility of optimizing the devices performance. The two different active layers of sub-cells have non-overlapping light absorption scales, which make the light utilized more adequately. Therefore, the tandem architecture of devices can extend the light absorption within the solar spectrum and effectively reduce energy loss resulting from thermalization loss and transmission loss. According to Shockley and Queisser's calculation, the limitation of the PCE of a tandem solar cell is 42%, which is higher than 33.8% of a single-junction solar cell. In organic photovoltaics field, the developments of the tandem solar cells benefit from the optimization of active layers, interconnecting layers and construction methods. These achievements have resulted in higher PCEs and the devices approaching practical application. At present, the highest PCE of tandem organic solar cell is 17.3% obtained by Chen's group in 2018, but it is still far from the PCE limitation. According to Kirchhoff's law, the open-circuit voltage (V_OC) in series tandem cells is theoretically equal to the sum of the V_OCs of sub-cells, and the short-circuit current (J_SC) in parallel cells is equal to the sum of the J_SCs of sub-cells. Hence, the series tandem solar cells still face with the challenge of the unmatched J_SCs and the complexed processing methods. Here, this review mainly focuses on the materials used in tandem solar cells, the structure of the interconnecting layers, the processing methods, the measurement methods and the applications. The critical achievements on tandem organic solar cells in recent years and the progress of larger scale, flexible tandem devices are summarized in this review. It also presents the outlooks of the high performance tandem solar cells based on the material and structure requirements.

Decarboxylation of N-hydroxyphthalimide (NHPI) esters represents a powerful tool to generate carbon radicals, which has wide applications in the construction of C—C bonds and C—X bonds. Traditionally, the radical decarboxylation of NHPI esters has been enabled by transition-metal catalysis and photoredox catalysis. Recently, several visible light-mediated photosensor-free decarboxylation reactions have been reported with the use of special electron-donor systems. While notable, it’s still highly desirable to develop transition-metal-free, mild, and general methods to realize the radical decarboxylation of NHPI esters. Herein, we report 4-dimethylaminopyridine (DMAP)-boryl radical enabled Giese reaction and Barton decarboxylation of NHPI esters. The reaction starts from the generation of DMAP-boryl radical in the presence of a radical initiator, which then adds specifically to the carbonyl oxygen atom of NHPI ester 2, followed by β-fragmentation to give a nucleophilic carbon radical intermediate. Addition of the carbon radical to electron-deficient alkenes affords the Giese reaction product 4. On the other hand, hydrogen atom transfer from thiol to the nucleophilic carbon radical results in the Barton decarboxylation products 5. The reactions exhibit a broad substrate scope and excellent functional group tolerance. NHPI esters of primary, secondary, and tertiary alkyl carboxylic acids, including bio-active natural products and drugs, proceed smoothly to give the corresponding products in moderate to good yields. A variety of electron-deficient alkenes, such as vinyl esters, vinyl amides and vinyl sulphones, can be used as the Michael acceptors. A general procedure for the Giese reaction is as following: a solution of NHPI ester 2 (0.5 mmol), 4-dimethylaminopyridine-borane (0.6 mmol), AIBN (0.1 mmol) and electron- deficient alkenes 3 (0.4 mmol) in toluene (4.0 mL) was stirred at 80 ℃ for 4 h under nitrogen atmosphere. After evaporation of solvent, the crude residue was purified by flash column chromatography on silica gel (petroleum ether/ethyl acetate) to afford Giese reaction product 4. A general procedure for the Barton decarboxylation is as following: a solution of NHPI ester 2 (0.5 mmol), 4-dimethylaminopyridine-borane (0.55 mmol), TBHN (0.1 mmol) and PhSH (0.1 mmol) in benzotrifluoride (5.0 mL) was stirred at 80 ℃ for 1 h under nitrogen atmosphere. After evaporation of solvent, the crude residue was purified by flash column chromatography on silica gel (petroleum ether/ethyl acetate) to afford decarboxylative reduction product 5.

Recovering C₂H₄ from refinery gas is an effective way to broaden the source of ethylene. However, it's a challenging task to separate C₂H₄ and C₂H₆ due to their very close physical properties and molecular size. Metal-organic frameworks (MOFs) are shown broad prospects in the field of light hydrocarbon separation in recent years. In this work, NH₃ is used to modify the structure of UTSA-280, the efficient separation of C₂H₄/C₂H₆ can be achieved through the adjustment of one-dimensional channels. UTSA-280 has undergone stepwise adsorption of ammonia gas at 298 K and 100 kPa. After partial ammonia removal, we obtained the modified UTSA-280 that ammonia adsorption modification with a mass loading of 5.6% for UTSA-280-M1 and 2.8% for UTSA-280-M2. The NH₃ modified UTSA-280 shows a unique ultramicroporous structure that can enhance the adsorption of C₂H₄ and does not adsorb the slightly larger C₂H₆, achieving the ideal C₂H₄/C₂H₆ adsorption selectivity (more than 1000). Ammonia molecules play the role of perfectly adjusting the size of one-dimensional channels and realize the ideal screening effect of C₂H₄/C₂H₆. The C₂H₄ adsorption capacity of NH₃ modified UTSA-280-M2 can be improved to 2.83 mmol/g at 298 K and 100 kPa (an increase of 29% compared with initial material). And its ultramicroporous structure can fully block the adsorption of C₂H₆, which finally achieves a C₂H₄/C₂H₆ selectivity over 1200. Grand Canonical Monte Carlo (GCMC) simulation of C₂H₄/C₂H₆ mixed gases (equal volume) adsorption results showed that the modified UTSA-280 had more C₂H₄ adsorption distribution in the mixed components than C₂H₆. Through the C₂H₄/C₂H₆ mixed gases breakthrough test at 298 K, NH₃ modified UTSA-280-M2 shows a separation time of more than 48 min, which is more than the initial 25 min. Compared with the unmodified material, the separation performance is nearly doubled. Scalable synthesis, stable structure, and the advantages of controllable performance after ammonia modification have prompted this material to have great prospects in the industrialization of C₂H₄/C₂H₆ separation.

Optically pure pyrrolidine ring systems are core structural motifs found in a range of bioactive compounds, natural products, pharmaceuticals and catalysts. The synthesis of optically pure pyrrolidine ring systems is no longer mysterious as a great number of studies concerning the catalytic asymmetric 1,3-dipolar cycloaddition of iminoesters have been reported. Overall, the transition-metal-catalyzed asymmetric 1,3-dipolar cycloaddition of iminoesters with electron-deficient alkenes is one of the most powerful and straightforward synthetic tools for the optically pure pyrrolidines. However, high diastereo-and enantioselectivities are requested simultaneously during the synthesis of chiral substituted pyrrolidine and it still remains a big challenge to develop an efficient way to achieve both of them. Recently, we developed a novel chiral sulfinamide mono-phosphine (Ming-Phos) which performed well in copper-catalyzed intermolecular cycloaddition of iminoesters with β-trifluoromethyl β,β-disubstituted enones or α-trifluoromethyl α,β-unsaturated esters. Encouraged by the satisfying results, herein we report the Ming-Phos/Cu-catalyzed asymmetric intermolecular[3+2] cycloaddition of azomethine ylides with nitroalkenes. To our delight, a new Ming-Phos M3 bearing a trifluoromethyl showed good performance in this type of inter-molecular cycloaddition with high diastereo-and enantioselectivities (up to 13:1 dr, 98% ee and 95% yield). High efficiency, high diastereo-and enantioselectivity, a novel ligand, an inexpensive copper catalyst, and good functional group tolerance make it worth to be considered as an efficient, reliable and atom-economic strategy for the synthesis of optically pyrrolidines. The general procedure is as following:the solution of M3 (5.5 mol%) and Cu(CH₃CN)₄BF₄ (5 mol%) in methyl tert-butyl ether (MTBE, 6 mL) was stirred at room temperature for 2 h. After the reaction temperature was dropped to -30℃, azomethine ylides 2 (0.6 mmol), Cs₂CO₃ (0.15 mmol) and nitroalkene 1 (0.3 mmol) were added sequentially. After the nitroalkene 1 was consumed completely, the solvent was removed under reduced pressure. The crude product was analyzed with ¹H NMR to determine the diastereomeric ratio. Then the crude product was then purified by flash column chromatography on silica gel to afford the desired product.

Covalent organic framework materials (COFs) are a class of organic porous materials with large specific surface area, high porosity and crystallinity. Owning to their special nature of functional versatility and easy modification, COFs can be designed to be efficient catalysts either embed functional active sites into the skeleton through a "top-down" strategy, or load metal nanoparticles into the framework via a post-modification approach. These studies have laid the foundation for the extension of COF's application in heterogeneous and other catalytic fields. The synthetic strategy and application of COF in different types of catalytic reactions are reviewed in this paper. Moreover, the current research situation of COF catalyst is summarized and prospected. Finally, the remaining challenges in this field are also indicated.

As inexpensive and readily available feedstocks, alkenes possess a unique reactivity profile and thus have been extensively applied in synthetic chemistry. Specifically, radical-triggered difunctionalization of alkenes provides a valuable synthetic strategy for their high utilization by incorporating two functional groups across the C=C π system. Despite the great achievements gained in this field, the vast majority of well-developed methods generally focus on activated alkenes, because its nascent alkyl radical needs to be stabilized by adjacent functional groups (e.g. aryl, carbonyl, heteroatom) via p-π conjugate effect. However, radical induced difunctionalization of unactivated alkenes remains elusive. Herein, a new protocol for Fe(III) mediated hydroalkynylation of unactivated olefins is reported. By using the characteristics of the in-situ-generated hydrogen radical from the interaction of Fe(acac)₃ and phenylsilane, hydrogen radical-triggered intramolecular 1,2-alkynyl migration was realized in this reaction, which led to the synthesis of a series of α-alkynyl ketones with moderate to good yields. Based on the experimental results and literature reports, a reasonable reaction mechanism was proposed, which involved hydrogen radical addition, 3-exo-dig cyclization (anti-Baldwin rules) and C—C bond breaking/recombination. Moreover, the reaction features good tolerance of functional groups, in which estrone-derived 1,4-enyne could be accommodated. A typical procedure for hydroalkynylation of unactivated alkenes is as follows: Fe(acac)₃ (1.2 equiv., 0.24 mmol) and NaHCO₃ (1.0 equiv., 0.2 mmol) are added to the 10-mL pressure tube. Then 1,4-enynes (1.0 equiv., 0.2 mmol) and phenylsilane (2.0 equiv., 0.4 mmol) are dissolved in 1.0 mL ethyl alcohol, respectively. Both of them are injected into this vial. The reaction system was sealed and stirred at 100 ℃ until the 1,4-enynes consumed that is determined by thin layer chromatography (TLC). After the reaction completes, the resulting mixture is extracted with EtOAc for three times, then the organic phase is concentrated and evaporated on a rotary evaporator. The residue was purified by chromatography on silica gel with petroleum ether/ethyl acetate (V∶V=75∶1) as the eluent to afford α-alkynyl ketones.

The selective functionalization of unactivated sp ³ carbon-hydrogen (C—H) bond is an attractive strategy in modern organic transformation. The hydrogen atom transfer (HAT) catalysis has recently shown its advances in remotely selective activation of an inert C—H bond with great functional group compatibility, generating new carbon-carbon (C—C) bonds and carbon-heteroatom (C—O, C—N, C—X) bonds. Therefore, the remote sp ³ C—H functionalization has become an intensively investigated research area, drawing extensive attention in synthetic community. Particularly, the 1,5-hydrogen atom abstraction of nitrogen radicals, the key step of the Hoffman-L?ffler-Freytag (HLF) reaction, has been widely applied in the preparation of heterocycles. Comparing to the well-studied area of nucleophilic N-species, N-centered radical based reactions are still underdeveloped. The limited utility is partially due to the required use of hazardous radical initiators, elevated temperatures, or high-energy UV irradiation for the generation of N-radicals. Recently, visible-light photoredox catalysis has been leading efficient accesses to Nitrogen-radicals under mild conditions. The visible-light-induced nitrogen radical formation has also stimulated the development of the remote sp ³ C—H functionalization by photoredox catalysis. The classic HLF reaction requires pre-functionalization at N-center in the substrate to promote the formation of N-radical. Recently, a direct N—H single electron transfer (SET) oxidation was realized by photoredox catalysis in Knowles and Rovis’s group, generating N-radicals efficiently. The processes significantly simplified the preparation of the HLF reaction substrates and broaden the application of this classic reaction. In addition, the visible-light-induced nitrogen radical-directed reaction on modified imines provided possibilities for the remote sp ³ C—H functionalization of ketones, as ketone is the product of imine hydrolysis. Moreover, the application of chiral Lewis acid catalysis combined with visible-light photoredox catalysis enabled the asymmetric alkylation of the unactivated remote sp ³ C—H position, which achieves both regioselective and stereoselective functionalization. In conclusion, this strategy takes advantage of mild generation of N-radicals upon visible-light excitation. Subsequent 1,5-hydrogen atom transfer (1,5-HAT) and intermolecular radical coupling would realize the remote functionalization of unactivated sp ³ C—H bonds. The strategies have been successfully applied in remote C(sp ³)—H amidation, fluorination, chlorination, iodination, alkylation, vinylation, allylation, oxygenation, thioetherification, cyanation and alkynylation. In this review, we focus on visible-light-induced nitrogen radical directed functionalization of remote sp ³ C—H bonds, summarized the methodologies, and briefly reviewed their synthetic applications in pharmaceuticals and natural products.

The electrolyte, which is an important medium of ion conduction for secondary batteries, plays a crucial role in improving the cycling performance and safety performance of secondary batteries. Localized high-concentration electrolytes, which are formed by adding "diluent" into high-concentration electrolyte, not only reserve the outstanding properties of high-concentration electrolytes but also possess low viscosity, excellent wettability and low cost, promising broad application prospect. Localized high-concentration electrolytes have already played a part in flame-retardant lithium battery, high-voltage lithium battery, low-temperature lithium battery, lithium sulfur battery and sodium battery. Herein, this paper mainly reviews the types and preparation of localized high-concentration electrolytes and their functional mechanism and research status in various secondary batteries. We discuss the challenges and future development of localized high-concentration electrolytes and have the outlook at the end of the paper.

Single-molecule magnets (SMMs), exhibiting magnetic bistability and slow magnetization relaxation, have fascinated scientific community for their promising applications in data storage and information processing. Great development has been achieved in lanthanide-based SMMs due to the unquenched orbital momentum and strong anisotropy of lanthanide ions. According to the crystal-field theory, the magnetic anisotropy of lanthanide ions arises from crystal-field splitting. Appropriate arrangement of coordination environment of lanthanide ion (including the local symmetry as well as the charge distribution) is key to design high-performance SMMs. However, it still remains a huge challenge to generate lanthanide-containing compounds with certain coordination environment. Taking advantage of metallacrown (MC) approach, herein a series of 3d-4f complexes {TbNi₅X₂} (X=F, Cl, Br) were successfully isolated via solvothermal reactions. To obtain these complexes, a mixture of stoichiometric metal salt and quinaldichdroxamic acid with excess of pyridine derivative was dissolved in methanol and then heated at 75℃ for 2 d. X-ray single-crystal diffraction analysis indicated that the Tb(III) site equatorially coordinates with[15-MC_Ni(II)-5], whilst is axially capped by halide ions. As a result, the lanthanide ion possesses high axiality with a pentagonal bipyramid geometry (D_5h). Alternative current magnetic susceptibility data revealed that the electrostatic interactions between f-electrons and ligand electrons play an important role in modulating the magnetic relaxation dynamics. Maximizing the axial charge density in {TbNi₅F₂} where the[F-Ln-F]⁺ moiety is firstly reported in lanthanide chemistry, the oblate Tb(III) is placed in a judicious crystal field. The out-of-phase signal of {TbNi₅F₂} shows obvious temperature and frequency dependence under 1 kOe applied dc field. Additionally, the slow magnetization relaxation of {TbNi₅F₂} can be fitted by the power law or Arrhenius plot with reversal barrier of 19.0 K. By lowering the electrostatic interactions of axial ligation, the out-of-phase signal significantly weakens in {TbNi₅Cl₂} and even vanishes in {TbNi₅Br₂}. The decline of magnetic anisotropy in {TbNi₅Cl₂} and {TbNi₅Br₂} accelerates the fast quantum tunneling of magnetization. The results demonstrate for the first time that the Off/Part/On slow magnetization relaxation can be modulated via the improvement of electronegativity of axial ligands.

Metal-organic frameworks (MOFs), a class of promising heterogeneous catalysts, though readily recyclable, usually suffer from poor dispersity and ease of sedimentation in liquid-phase reaction systems, which may lead to limited exposure of active sites and unsatisfied activity. Conventional hydrothermal synthesis often results in large MOF particles in bulk form and poor dispersity. The homogenization of MOF catalysts is an exciting but challenging task to integrate the advantages of both homogeneous and heterogeneous catalysts. Herein, by means of microwave-assisted synthetic approach, a soluble porphyrinic MOF, denoted as S-Al-PMOF, has been successfully fabricated. In contrast to the Bulk-Al-PMOF synthesized by the conventional hydrothermal route, which requires 180℃ and 16 h, the S-Al-PMOF obtained by the microwave-assisted method is very efficient and takes 30 min only at 140℃. While the as-synthesized S-Al-PMOF can be completely soluble in acetonitrile by ultrasonic dispersion to give a clear and transparent colloidal solution, the Bulk-Al-PMOF can form a turbid suspension liquid by continuous stirring, which easily aggregate with sedimentation in a short time after standing. Furthermore, the S-Al-PMOF can be easily separated from the solution by suction filtration and then re-dissolved in acetonitrile. This separation and re-dissolution process can be repeated several times to prove its good recovery and recycling. Given the outstanding light harvesting ability of Al-PMOF, photocatalytic H₂ production by water splitting has been adopted to examine the activity of both S-Al-PMOF and Bulk-Al-PMOF. As a result, the activity of S-Al-PMOF is around 14 times higher than that of Bulk-Al-PMOF, owing to excellent solubility of the former. Moreover, S-Al-PMOF also exhibits good recyclability in the consecutive three cycles of reaction. We believe that the successful synthesis of soluble Al-PMOF opens a new avenue to the homogenization of heterogeneous catalysts.

As important chemical raw materials and energy source, C₄~C₆ hydrocarbons are mainly used to produce polymer rubber, plastics and high-quality gasoline, which requires high purity of the raw materials. For example, the purity requirement in 1,3-butadiene polymerization reactor is higher than 99.5%. When producing butyl rubber, tert-butylamine, pivalic acid, etc., the purity of isobutylene should surpass 99%. In the traditional petrochemical industry, C₄~C₆ hydrocarbons are mostly separated and purified through distillation, yet suffering from large energy consumption, high equipment cost and poor economic benefits. Adsorption separation with solid adsorbents can not only reduce energy cost and environmental footprints, but also improve separation efficiency. Metal-organic frameworks (MOFs) are a class of crystalline porous materials assembled from metal ions or clusters and organic linkers. Compared with zeolite, activated carbon and silica gel, MOFs feature high porosity, well-defined open channels, rich functional groups and diverse structures, showing great potentials in gas storage and separation, sensing, catalysis, photoelectric devices, drug release and delivery. Up to now, there have been many reports on separation and purification of C₄~C₆ hydrocarbons using MOFs by different mechanisms. Specifically, highly selective separation can be achieved by precisely adjusting the size and shape of the MOF channels to match the size of the target molecule. Besides, selecting MOFs with specific functional groups, open metal sites or flexible skeletons to regulate the interactions between the gas molecules and backbone, can also achieve efficient separation. This review introduced the importance of C₄~C₆ hydrocarbons separation and summarized the current research progress of using MOFs to separate and purify C₄~C₆ hydrocarbons. In addition, we also summed up the challenges of using MOFs as industrial adsorbents and pointed out the possible research directions in the future, which may provide ideas for designing new MOFs with high performance for crucial separation processes.

With the accelerating process of industrialization and urbanization, as well as the increasing proportion of the elderly in the world's population, we are facing more complex health threats related to bacterial infection. While the vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, the continued abuse and misuse of antibiotics has accelerated the spread of antibiotic-resistant bacterial strains and has resulted in substantial new challenges with respect to modern-day antibiotic-based treatments. Therefore, intelligent design of new antibacterial modalities to be used for treating human and livestock diseases is an extremely urgent priority for researchers in the fields of chemistry, chemical engineering, materials and biomedical sciences. Toward this end, the most intriguing of the new developments are metal-organic frameworks (MOFs). MOFs are versatile crystalline porous lattices of organic ligands and metal ion/clusters that formed by self-assembly via coordination bonds. Due to their unique characteristics, including relatively straight forward and simple methods for synthesis, large surface areas, novel and diverse structures, and adjustable porosity, MOFs not only play strong roles with respect to novel methods for gas storage and separation, they may also be utilized in unique applications associated with sensors mechanisms and catalysis. These features contribute to our current understanding of MOFs as promising candidates for the development of pharmaceutical and specifically antibacterial applications. In this review, antibacterial mechanisms, and the development of resistance to current antibiotic strategies are summarized and discussed. The main mechanisms by which bacteria show resistance to antibiotics include altered metabolic pathways, regulation of target sites, and inactivation, modification, and/or reduction in the capacity to accumulate antibacterial drugs. We consider recent progress on the development of MOFs, including the use of specific metal centers and ligands, metal nanoparticles, and drug-encapsulation, all of which have important applications with respect to antibacterial activities, and wound healing. Finally, the challenges and prospects of MOF-based antibacterial materials are discussed, including critical findings, which will help toward the development of the next generation antibacterial MOFs for human use.

Apigenin-7-O-β-D-glucuronide (1) and scutellarin (scutellarein-7-O-β-D-glucuronide, 2) are two major flavone glucuronide components occurring in breviscapines, which are prepared from the traditional Chinese herb Erigeron breviscapus. These two flavone glycosides show potent anti-oxidative, anti-inflammatory and neuroprotective activities in various evaluations. Synthesis of these natural glycosides in an efficiently manner would facilitate studies on their structure activity relationships. As a persistent effort on the chemical syntheses of the diverse glycoconjugates from traditional Chinese herbs in our group, we report herein the synthesis of these two representative flavone O-glucuronides. It is known that the solubility of flavone compounds is rather low and this property would greatly hinder their glycosylation reactions. In order to increase the solubility of the flavone derivatives in the glycosylation solvents, hexanoyl and benzyl groups were selected as the permanent protecting groups for the hydroxyl groups of apigenin (7) and scutellarein (8). The construction of the phenolic O-glucuronide is known to be a difficult task, especially the glycosylation of the poorly nucleophilic 7-hydroxyl group which locates at the para-position of the flavone carbonyl group. We achieved the glycosylation of the flavone 7-OH with 2,3,4-tri-O-benzoyl-6-O-TBDPS-glucopyranosyl ortho-alkynylbenzoate (9) under the catalysis of Ph₃PAuNTf₂ (0.2 equiv., 4 ? MS, CH₂Cl₂, r.t., 5 h) in excellent yields. After that, the 6-O-TBDPS groups were removed, and the requisite glucuronides were then elaborated by oxidation of the resulting 6-OH under the conditions of DAIB/TEMPO (CH₂Cl₂/H₂O, V∶V=2∶1, r.t.) in good yields. After global deprotection, the desired products apigenin-7-O-β-D-glucuronide (1) and scutellarin (2) were obtained in overall yields of 36% (5 steps) and 7% (9 steps), respectively, from the starting flavone aglycones. Following the same strategy, four naturally occurring flavone-7-O-glycosides, namely apigetrin (3), plantaginin (4), apigenin 7-O-β-D-xylopyranoside (5) and apigenin 7-O-α-L-rhamnopyranoside (6), were smoothly synthesized in 4~7 steps with the overall yields of 61%, 13%, 58% and 61%, respectively.

Radical-mediated difunctionalization of alkenes through the remote functional group migration (FGM) process paves an ingenious avenue for simultaneous cleavage and reconstruction of C—C bonds. Recently, our group has systematically disclosed the strategy of remote FGM for radical-mediated difunctionalization of unactivated alkenes. A portfolio of functional groups including cyano, heteroaryl, alkynyl, oximino, and carbonyl showcase the migratory aptitude, leading to new C—C bonds under radical conditions. Meanwhile, a series of other chemical bonds such as C—C, C—N, C—P, C—Si, and C—S are readily constructed in the reaction. Considering the synthetic utility and flexible transformation of alkynes, the radical alkynylation of unactivated alkenes via remote alkynyl migration we firstly reported provides an efficient approach for the incorporation of alkynes and has received considerable attention. On the other hand, fluorine- and sulfonyl-containing molecules play vital roles in organic and medicinal chemistry owing to their important chemical and physical characters. Therefore, the concomitant introduction of an alkynyl and a trifluoromethyl/sulfonyl group into one molecule is of great synthetic value. Herein we report a useful method for carbo-trifluoroalkylation/sulfonylation of unactivated olefins. The addition of extrinsic radical to alkene triggers the intramolecular FGM via a five-membered transition state along with a cascade of bond fission and formation. The typical procedure is as follows: a mixture of propargyl alcohol 1, sulfonyl chloride, fac-Ir(ppy)₃, and base is loaded in a flame-dried reaction vial which is subjected to evacuation/flushing with nitrogen three times. Solvent is added to the mixture via syringe and the mixture is then stirred at 25 ℃ until the starting material is consumed monitored by TLC. The mixture is concentrated, and purified by flash column chromatography on silica gel (eluent: petroleum ether/ethyl acetate) to give the product.

Two thermally activated delayed fluorescence (TADF) materials TBP-DmCz and TBP-TmCz were successfully synthesized using 1,3,5-tribenzoylbenzene (TBP) as electron-acceptor, 1,8-dimethylcarbazole (DmCz) and 1,3,6,8-tetra-methylcarbazole (TmCz) as electron-donor, respectively. Thermal gravimetric analysis show that the thermal decomposition temperatures (T_d) are 479℃ for TBP-DmCz and 484℃ for TBP-TmCz and no glass transition was found for both materials during the differential scanning calorimetry investigations. The highest occupied molecular orbitals (HOMO) are confined on the carbazole unit, while the lowest unoccupied molecular orbitals (LUMO) are located on the 1,3,5-tribenzoylbenzene unit, and there is almost no overlap between HOMO and LUMO, which is the typical molecular orbital character of TADF materials. Meanwhile, TBP-DmCz and TBP-TmCz possess degenerated HOMO and LUMO, which would promote the radiative transitions as the transitions could take place from all degenerated LUMOs to HOMOs. The HOMO level of TBP-TmCz is obviously higher than that of TBP-DmCz due to increasing the number of methyl groups at the electron-donor carbazole, and the LUMO levels of TBP-DmCz and TBP-TmCz only show a small difference because these materials have the same electron-acceptor 1,3,5-tribenzoylbenzene. In toluene solution, these materials have very similar absorption spectra and exhibit absorption bands assigned to intramolecular charge-transfer transition. The spectral peaks are located at 488 nm for TBP-DmCz and 502 nm for TBP-TmCz, respectively, in toluene solution at room temperature. According to the fluorescence and phosphorescence spectra of these materials in 1,3-bis(N-carbazolyl)benzene (mCP) film at 77 K, the energy gaps between the lowest singlet and triplet (ΔE_ST) of TBP-DmCz and TBP-TmCz are calculated to be 0.05 and 0.01 eV, respectively. The fluorescence decay behaviors at different temperatures (100, 200 and 300 K) proved that emissions of TBP-DmCz and TBP-TmCz contain TADF component. The electroluminescence devices with TBP-DmCz and TBP-TmCz as the emitters show high efficiency and low efficiency roll-off. The maximum external quantum efficiencies of devices based on TBP-DmCz and TBP-TmCz are 13.6% and 18.3%, respectively.

With the rapid development of electric cars and energy storage power stations, there is an increasing demand for lithium ion batteries with high energy density. Li- and Mn-rich (LMR) cathode materials with large specific capacity (>250 mAh·g^-1) are supposed to accomplish lithium ion batteries with high energy density (>350 Wh·kg^-1). The high capacity performance of LMR cathode materials are resulted from the lattice oxygen redox reaction induced by the electrochemical activation of the Li₂MnO₃ phase. However, the activation of the Li₂MnO₃ phase and oxygen redox reaction lead to lattice oxygen release and structure transformation, which cause some serious problems such as low initial columbic efficiency, poor rate capability, voltage and capacity degradation after subsequent cycles. The oxygen release and structure transformation always start from the surface, indicating that the surface stability is significant to LMR cathode materials. In this paper, surface modifications such as surface coating, surface doping and surface chemical treatment are reviewed and the mechanism of three surface modification methods for LMR cathode materials are discussed in further. Surface coating is one of the most widely surface modification methods, which can suppress the electrode/electrolyte side reaction and reduce the transition metal dissolution. The effect of surface coating on improving electrochemical performance of LMR cathode materials is always determined by the characteristic of coating layer materials including non-active coating layer, electrochemical active coating layer, Li⁺ conductive coating layer and electronic conductive coating layer. Surface doping has shown to be an effective method in suppressing oxygen release and structural transformation. Surface chemical treatment has resulted in reducing irreversible capacity loss by activating Li₂MnO₃ phase. On this basis, surface integrated strategies combined several surface modified methods are introduced and discussed in recent years. The surface intergrated strategies not only enhance the structural stability and suppress electrode/electrolyte surface-interface reaction, but also have an effective role on mitigating structure transformation and lattice oxygen release. Finally, we wish that our review would provide research directions for surface modified strategies of LMR cathode materials in future.