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Polycrystalline K2Ti8O17 is prepared by hydrothermal reaction of (BuO)4Ti and KOH in a 1:1 mixture of ethylene glycol and H2O (autoclave, 200 °C, 20 h) followed by calcination in air (700 °C, 12 h).

The protocol enables smooth, rapid, and mild Negishi reactions to give the biaryls in excellent yields.

Large surface area, small size, strong optical properties, controllable structural features, variety of bioconjugation chemistries, and biocompatibility make many different types of nanoparticles (NPs), such as gold NPs, useful for many biological applications, such as biosensing, cellular imaging, disease diagnostics, drug delivery, and therapeutics. Recently, interactions between proteins and NPs have been extensively studied to understand, control, and utilize the interactions involved in biomedical applications of NPs and several biological processes, such as protein aggregation, for many diseases, including Alzheimer's disease. These studies also offer fundamental knowledge on changes in protein structure, protein aggregation mechanisms, and ways to unravel the roles and fates of NPs within the human body. This review focuses on recent studies on the roles and uses of NPs in protein structural changes and aggregation processes.

Six steroid derivatives including the novel, highly conjugated one (I), and five known butyrolactone derivatives are isolated and their structures are elucidated based on NMR and MS data.

A novel organocatalytic asymmetric tandem Nazarov cyclization/semipinacol rearrangement reaction using "unactivated" substrates has been developed, generating a series of chiral spiro[4.4]nonane-1,6-diones in up to 96% yield and 97% enantiomeric excess. Significantly, it is the first direct example for asymmetric synthesis of cyclopentanones with four stereocenters using Nazarov cyclization. DFT calculations have been applied to understand the reaction mechanism, stereochemistry, and substituent effects.

Benzyl sulfonamide/alcohol-tethered alkylidenecyclopropanes undergo a rhodium-catalyzed and substrate-controlled selective C-C bond activation, producing three types of common organic structural units: benzo[c]azepine/oxepines, dihydronaphthalen-1-amines, and conjugated dienes. Epoxidation and aromatization of these products to construct two useful compounds have also been achieved.

An efficient synthesis of 2-perfluoroalkyl 2H-chromenes 3 (RF = CF3, C2F5) was developed via regioselective cycloaddition of salicylaldehydes 1 and methyl perfluoroalk-2-ynoates 2 in refluxing methanol. 2-Perfluoroalkyl-2H-chromenes 3 was regioselectively obtained in moderate to good yields by using l -proline as organocatalyst. Low toxicity, high regioselectivity, easy available starting materials, mild reaction conditions can be observed in this method.

A facile and consecutive one-pot, multi-component reaction for synthesis of trifluoromethylated spirochromeno[2,3- c ]-6 H -pyrazol-2′,5-dione derivatives by the reaction of isatin, cyclohexane-1,3-dione and 1-aryl-3-(trifluoromethyl)-1 H -pyrazol-5(4 H )-one in the presence of p - toluenesulfonic acid ( p -TSA) with good yields was reported. Compared with the stepwise reactions, the p -TSA played dual roles as both catalyst and dehydrating agent in the conversion. The structures of new compounds were determined by spectroscopic methods and X-ray diffraction analysis. In addition, a possible mechanism for the formation of compound 5 was presented.

The enantioselective synthesis of α-acyloxy-α-alkylmalonates was developed as an efficient method for producing chiral α-tertiary alcohols, which are potentially valuable intermediates in the synthesis of natural products and pharmaceuticals. The efficient enantioselective α-alkylation of diphenylmethyl tert-butyl α-acyloxymalonates was accomplished via phase-transfer catalysis in the presence of (S,S)-3,4,5-trifluorophenyl-NAS bromide to afford the corresponding α-acyloxy-α-alkylmalonates at high chemical (up to 99%) and optical (up to 93% ee) yields, which could be readily converted to versatile chiral intermediates with a chiral α-tertiary alcohol group.

An unprecedented Lewis acid catalyzed, protection-free, and high-efficiency synthesis of valuable 3,4-dihydro-2H-2,4-methanochromans via cycloaddition of propargylic alkynols with 2-vinylphenol is described. This cycloaddition protocol, which tolerates a wide variety of functional groups, provides practical, versatile, and atom-economical access to a new class of appealing bridged-ring products in satisfactory yields. Compared with the reported reaction conditions for bridged-ring skeletons synthesis, the present reaction conditions are neutral, mild, and without any additives.

Mg17Ba2 hydrogen storage alloy was obtained by induction melting, and its hydrogen storage properties and phase transitions have been investigated. The reversible hydrogen capacity of Mg17Ba2 compound was 4.0 wt% H2. A three-step dehydrogenation mechanism was revealed for the first time, and a new hydride (Ba2Mg7H18) was discovered during the dehydrogenation process. Enthalpy and entropy changes for the dehydrogenation of Mg17Ba2 were also calculated.

A novel cinchona-alkaloid-derived organocatalyst has been developed to catalyze the asymmetric regioselective [3+2] cycloaddition of 3-isothiocyanato oxindoles with dibenzylidene ketones. A series of spirooxindole enols could be obtained in high yields with good-to-excellent diastereo- and enantioselectivities.

A highly diastereoselective dearomatization of indoles via palladium-catalyzed decarboxylative alkynyl termination was developed. This protocol provides dissimilar tetracyclic and tetrasubstituted indoline scaffolds bearing congested stereocenters, which led to operationally simple conditions, short time, and broad substrate scope. Additionally, this reaction system could be scaled to gram quantities in a satisfactory yield and diastereoselectivity.

A convenient and efficient approach for the synthesis of 1-alkenylisoquinolines and 2-alkenylquinolines was developed via palladium-catalyzed coupling reactions between isoquinoline/quinoline N -oxides with olefins under external-oxidant-free conditions. Biological evaluation revealed that some of the obtained 1-alkenylisoquinolines exhibited in vitro antiproliferative activities on human-derived prostate, breast, esophageal, and stomach cancer cell lines.

A novel visible-light-induced trifluoromethylation of isonitrile-substituted methylenecyclopropanes is developed. A range of substituted 6-(trifluoromethyl)-7,8-dihydrobenzo[k]phenanthridine derivatives are readily furnished by this newly developed tandem trifluoromethylation reaction with moderate to good yields. This reaction allows the direct formation of two six-membered rings and three new C-C bonds including the C-CF3 bond under the irradiation by visible light.

A mild Zn-catalyzed intermolecular Diels–Alder/ene tandem reaction with styrene as a 4π-component is reported. A variety of dihydronaphthalene products could be prepared in moderate to good yields. Moreover, a combination of DFT calculations and experiments was performed to further understand the mechanism of this unique tandem reaction.

A series of indolyl substituted 1,4,6,7-tetrahydropyrano[4,3-c]pyrazole derivatives were synthesized via a domino method based on the 1,4:3,6-Dianhydrofructose. The mechanism was proposed and proved by calculation with a density functional theory (DFT), which includes formation of phenylhydrazone, furanone ring opening, Fischer indole synthesis, pyrazole ring closing and a furan ring expansion. In vitro antitumor activity of all synthesized compounds against four human cancer cell lines (MCF-7, EC-109, HGC-27, and PC-3 cell lines) were then evaluated, using MTT assay. We found that most of the compounds were more potent than the positive control 5-fluorouracil. Particularly, compound 4i against HGC-27 and PC-3, 4j against EC-109 cell lines showed three fold greater activity than 5-fluorouracil, respectively. The activity of compounds 4c and 4d against MCF-7 cell line was close to that of doxorubicin.

Thermoelectric materials can be used to directly and reversibly convert waste heat into electrical power and have attracted significant attention. Lead-free tin chalcogenide (SnTe, SnSe, SnS) thermoelectric materials are regarded as promising thermoelectric materials due to the great progress in the thermoelectric research field during the past several years. Analogous to PbTe, SnTe has a simple high symmetry NaCl-type cubic structure and a complex band structure, leading to its capability of achieving high thermoelectric performance by band structure and microstructure engineering. SnSe/SnS are simple compounds but exhibit an intrinsically ultralow thermal conductivity, suggesting that a high thermoelectric performance can be realized also in simple layered, anisotropic and anharmonic systems, without nanostructuring. This short perspective summarizes some current strategies that could enhance the thermoelectric performance of bulk lead-free tin chalcogenides, such as band structure engineering, nanostructuring, and synergistically improved approaches. Future possible strategies for further enhancing the thermoelectric performance of tin chalcogenides are also considered at the end of this perspective.

A novel copper-catalyzed difluoromethylation of 2- or 3-propargylamide-substituted indoles with ICF2CO2Et via a radical cascade cyclization process is described. A wide substrate scope is compatible with the reaction conditions to synthesize mono- and bis-difluoromethylated indoloazepinone derivatives, which contain a seven-membered ring.

Four new layered pentaborates Rb4Ba2.5B20O34Br, Rb2Ba4B20O34Br2, Rb4Ba2.5B20O34Cl, and KBaB5O9 have been successfully synthesized via a high-temperature solution method; the former three are the first series of compounds reported in the Rb-Ba-B-O-X (X = halogen) system. Interestingly, the structures of the above compounds are composed of the same [B5O11]7– fundamental building block (FBB), which could be further linked to form 2∞[B10O17]4– double layers for the former three compounds and 2∞[B5O9]3– single layers for the last one. The structure comparisons among all the available anhydrous pentaborates reveal that the structures of the anionic framework are affected by the relationship between the orientation of [B5O11]7– FBB axes and the layer plane (parallel or perpendicular), which will produce the different number of terminal O atoms in the initial pentaborate blocks. The viewpoints give us a feasible way to investigate the layered structures and expand the structural diversity of borates. Furthermore,...

Rare-earth-metal complexes stabilized by amine-bridged tri(phenolato) ligands were developed, and their activities in catalyzing transformations of CO2 were studied. A series of terminal epoxides and challenging disubstituted epoxides were converted into the respective cyclic carbonates in the presence of CO2 in yields of 58 to 96 %. In addition, these rare-earth-metal complexes also showed good activities in catalyzing three-component reactions of anilines, epoxides, and CO2, which generated 5-substituted-3-aryl-2-oxazolidines in yields of 48 to 96 %, as a useful strategy to construct oxazolidinones.

Chiral o -aniline sulfoxides serving as chiral sulfurous source were synthesized, from which new sulfonamide-pyridine ligands were made in three-steps. These compounds proved to be efficient S , N -ligands for enantiocontrol of palladium-catalyzed allylic substitutions of dimethyl 2-fluoromalonate. The induced effect of the Pd/ S , N -ligand catalyst on the enantioselectivity depends on the steric demand of the substituent on the sulfoxide moiety. This method provided the fluorine-containing allylic products with up to 94% ee .

Ag-catalyzed [6 + 3] cycloaddition of tropone with homoserine lactone derived azomethine ylides has been developed. The reaction works efficiently under mild conditions to give tricyclic spiropiperidines in moderate to excellent yields with excellent diastereoselectivities.

An efficient approach for the synthesis of highly functionalized pyrroles has been developed by a Pd(TFA)2-catalyzed tandem heterocyclization of 1-(1-alkynyl)cyclopropyl oxime derivatives under mild conditions. The reaction first proceeded via an intramolecular nucleophilic attack followed by a ring-opening process and then intermolecular nucleophilic attack as well as protonation to afford the desired products in moderate to excellent yields.

Sodium alkoxides are used as nucleophiles in the procedure and the corresponding alcohol acts as the solvent.

isolation and structure determination of a new pterocarpan flavonoid (I) and a new isoflavone glycoside (II) along with 30 known compounds

isolation, structure and cytotoxicity of five new secosteroids (I) and seven known analogues

Nickel(I) complexes were generated in situ from Ni (PPh3)2Cl2 using activated iron and the complexes combined with N,N′-bis(4-fluorobenzylidene) ethane-1,2-diamine (BFBED) were then used as a catalyst for the 1,4-addition reaction of arylboronic acids to α,β-unsaturated substrates. The reaction proceeded to completion and did not require the addition of a base but the addition of potassium iodide is crucial to this cross-coupling reaction. Moreover, experimental observations suggested a possible Ni(I)–Ni(III) catalytic cycle mechanism.

PdO nanoparticles bound on the surface of polystyrene beads are used as catalytic system for the reduction of nitroarenes and for the hydrodehalogenation of aryl halides, respectively.

A new method for the AgSCF3-mediated radical cascade difunctionalizing trifluoromethythiolation of alkynes with dearomatization is developed. This protocol provides a novel route to SCF3-substituted spirocyclic compounds via the formation of one C-SCF3 bond, one C-C bond, and one C-O double bond in a single step.

Under control of a chiral Bronsted acid catalyst, racemic indolines undergo intramolecular Povarov reactions with achiral aromatic aldehydes bearing a pendent dienophile. One enantiomer of the indoline reacts preferentially, resulting in the highly enantio- and diastereoselective formation of polycyclic heterocycles with four stereogenic centers. This kinetic resolution approach exploits the differential formation/reactivity of diastereomeric ion pairs.

Piscidin 1 (Pis-1) from hybrid striped bass possesses antibacterial activities with high cytotoxicity. Previously, we reported that Pis-1[NkG], where Gly8 was substituted with positively charged Lys peptoid in Pis-1, shows high antibacterial activity with more potent bacterial cell selectivity than parent Pis-1 and Pis-1[PG] with Pro substitution at Gly8. Here, we investigated the effects of hydrophobic peptoid substitutions on antimicrobial activity and cytotoxicity of Pis-1. We designed Pis-1[NaG] and Pis-1[NlG] peptides, where Gly8 was replaced with alanine or leucine peptoids. Although hydrophobicity was increased in Pis-1[NaG] and Pis-1[NlG] compared with that in Pis-1[NkG], Pis-1, and Pis-1[PG], these peptides retained high antibacterial activity and showed no hemolytic activity when used at 100 μM. All peptoid-substituted peptides penetrated well the bacterial membrane and localized inside of the cytoplasm, while Pis-1 and Pis-1[PG] depolarized membrane severely. The flexible hinge structure formed by peptoid residues compared with the rigid bent structure formed by proline may explain their differential mechanisms of action. Most hydrophobic peptide, Pis-1[NlG], showed the most efficient inhibition of LPS (lipopolysaccharide)-induced nitric oxide production, indicating that it can be a potent antimicrobial peptide with anti-inflammatory activities. Peptoid substitution may facilitate the development of potent peptide drugs with bacterial cell selectivity.

The 1,4-diazabicyclo[2.2.2]octane (DABCO) catalyzed divergent [3+2] annulation of C,N-cyclic azomethine imines with δ-acetoxyallenoates was developed; 5,6-dihydropyrazolo[5,1-a]isoquinolines and ethyl (Z)-3-acetoxy-3-tosylpent-4-enoates were afforded in moderate to good yields in a one-pot manner under mild conditions. This annulation reaction provides a highly efficient method to construct dinitrogen-fused heterocycles and ethyl (Z)-3-acetoxy-3-tosylpent-4-enoates at the same time.

A remote OH group-directed metal-free transformation of alkynes to carbonyl compounds has been developed. Using only HOAc and EtOH solvent, this reaction elegantly converts alkynes into valuable ketones by remote hydroxyl group activation. Through comparison and isotope labeling experiments, it was confirmed that the process operates via a hydration reaction involving an acetic acid molecule, instead of a water molecule.

A series of new magnesium copper pnictide intermetallics, A2Mg3Cu9Pn7 (A = Sr, Eu; Pn = P, As) and Eu5Mg2.39Cu16.61As12, were synthesized through high temperature flux reactions. By the single-crystal X-ray diffraction technique, their structures were accurately determined. Sr2Mg3Cu9P7, Eu2Mg3Cu9P7, Sr2Mg3Cu9As7 and Eu2Mg3Cu9As7 crystallize in the Zr2Fe12P7 structure type (S.G. P, no. 174) with cell parameters: a = 9.7736(19)/9.7417(7)/10.0550(10) A/10.0410(8) A, c = 3.9280(16)/3.9008(5)/4.0544(9)/4.0364(6) A, respectively, while Eu5Mg2.39Cu16.61As12 adopts the Zr5Co19P12 structure type (S.G. P2m, no. 189) with cell parameters of a = 13.2521(6) A and c = 4.0910(3) A. These compounds can be viewed as an extensive branch of the ternary RE−M−Pn system (RE = rare-earth elements; M = transition metals; Pn = pnictogen) with the metal-to-nonmetal ratio being close or equal to 2 : 1. Interestingly, with the divalent alkaline-earth cations being introduced, these metal-rich phases exhibit electron deficiency according to the DFT calculations. Eu2Mg3Cu9As7 is metallic based on the resistivity measurement, consistent with theoretical prediction, and the magnetic susceptibility data of Eu2Mg3Cu9As7 confirmed the divalent oxidation state and weak ferromagnetic coupling for the europium cations.

Metal-organic frameworks (MOFs), also known as coordination polymers, represent an interesting type of solid crystalline materials that can be straightforwardly self-assembled through the coordination of metal ions/clusters with organic linkers. Owing to the modular nature and mild conditions of MOF synthesis, the porosities of MOF materials can be systematically tuned by judicious selection of molecular building blocks, and a variety of functional sites/groups can be introduced into metal ions/clusters, organic linkers, or pore spaces through pre-designing or post-synthetic approaches. These unique advantages enable MOFs to be used as a highly versatile and tunable platform for exploring multifunctional MOF materials. Here, the bright potential of MOF materials as emerging multifunctional materials is highlighted in some of the most important applications for gas storage and separation, optical, electric and magnetic materials, chemical sensing, catalysis, and biomedicine.

A facile synthesis of highly functionized indanone fused multicyclic pyrrolines using the heterocyclic ketene aminal and ninhydrin is described. Derivative alkoxyl or amine substituted analogues were also directly achieved upon adding alcohols or amines as corresponding starting materials. The reaction conditions are environment friendly and have a good tolerance towards a variety of heterocyclic ketene aminals. A library including three series of molecularly diverse indanone fused pyrrolines with potential bioactivities was demonstrated to be rapidly constructed with good to excellent yields.

Artaboterpenoids A and B (1 and 2), two novel bisabolene-derived sesquiterpenoids, were isolated from the roots of Artabotrys hexapetalus. Their structures with absolute configurations were elucidated by spectroscopic methods, and electronic circular dichroism (ECD) analyses. Notably, 1 featured a novel carbon skeleton with a new C-2-C-10 linkage, and 2a and 2b, a pair of enantiomers, represented the first examples of 1,2-seco-bisabolene-type sesquiterpene lactones. 2a exhibited cytotoxic effects against HCT-116, HepG2, A2780, NCI-H1650, and BGC-823 cell lines with IC50 values of 1.38-8.19 μM. Plausible biogenetic pathways for artaboterpenoids A and B were proposed.

Highly efficient and diastereodivergent aza-Diels-Alder reactions have been developed to access either diastereomeric series of benzofuran-fused δ-lactams and dihydropyridines in nearly perfect stereoselectivity (d.r. >20:1, >99 % ee for all examples). The complementarity of N-heterocyclic carbene and chiral amine as the catalyst was demonstrated for the first time, together with an excellent level of catalytic efficiency (1 mol % loading).

In this Personal Account, we review the work of our group in the area of environmental and energy-related nanocatalysis over the past seven years. We focus on understanding the fundamental mechanisms that control the properties of atomic clusters and nanoparticles - a form of matter that is intermediate between atoms and their bulk counterpart. The emphasis is on the theoretical design of effective catalysts based on cheap and abundant elements. The main idea that stands behind our work is that even catalytically inactive or completely inert materials can be functionalized at the nanoscale via the size, structure, morphology, and support effects. Such an approach opens up new ways to design catalytically active systems based on materials never before considered as catalysts. In particular, we demonstrate that hexagonal boron nitride (h-BN), which has been traditionally considered an inert material, can be functionalized and become active for a number of catalytic reactions involving oxygen activation, oxidation by molecular oxygen, and the oxygen reduction reaction.

A novel iridium/acid co-catalysed transfer hydrogenative coupling strategy, enabling direct alkylation of C(sp3)–H bonds and atom-economic access to alkyl chain-lengthened N-heteroaromatics from six-membered 2-alkyl cyclic amines and aldehydes, has been demonstrated. This work has built an important basis to convert cyclic amines, a class of bulk chemical raw materials, into functionalized products.

A meticulously designed, polar, non-centrosymmetric lead borate chloride, Pb2BO3Cl, was synthesized using KBe2BO3F2 (KBBF) as a model. Single-crystal X-ray diffraction revealed that the structure of Pb2BO3Cl consists of cationic [Pb2(BO3)]+ honeycomb layers and Cl− anions. Powder second harmonic generation (SHG) measurements on graded polycrystalline Pb2BO3Cl indicated that the title compound is phase-matchable (type I) and exhibits a remarkably strong SHG response, which is approximately nine times stronger than that of potassium dihydrogen phosphate, and the largest efficiency observed in materials with structures similar to KBBF. Further characterization suggested that the compound melts congruently at high temperature and has a wide transparency window from the near-UV to the mid-IR region.

Lithium–air battery (LAB) technology is currently being considered as a future technology for resolving energy and environmental issues. During the last decade, much effort has been devoted to realizing state-of-the-art LABs, and remarkable scientific advances have been made in this research field. Although LABs possess great potential for efficient energy storage applications, there are still various technical limitations to be overcome before the full transition. It has been well recognized that the battery performance of LABs is mainly governed by the electrochemical reactions that occur on the surface of the cathode. Thus, the rational design of highly reliable cathodes is essential for building high-performance LABs. In this respect, we introduce recent advances in the development of LABs, particularly focusing on the cathodes based on a fundamental understanding of Li–O2 electrochemistry. Furthermore, we review the remaining technical challenges in order to formulate a strategy for future research and consolidate Li–O2 electrochemistry for successful implementation of LABs in the near future.

A de novo synthesis of a benzene ring allows for the preparation of a diverse range of heterocycles including indoles, benzofurans, benzothiophenes, carbazoles, and dibenzofurans from simple heteroaryl propargylic esters using a unified carbonylative benzannulation strategy. Multiple substituents can be easily introduced to the C4-C7 positions of indoles and related heterocycles.

A one-pot sequential asymmetric hydrogenation of β-aryl-β-aryloxy acroleins has been realized for the preparation of chiral 3-aryl-3-aryloxy alcohols with excellent yields and good enantioselectivities. This methodology can be employed in new synthetic routes for the synthesis of fluoxetine, atomoxetine, and related analogues.

Palladium nanoparticle (Pd NP) catalysts immobilized in a polymer with an N-heterocyclic carbene (NHC) moiety (PICB-NHC-Pd) have been developed, wherein the NHC moiety plays dual roles as a crosslinker and a ligand to activate the Pd NPs. The presence of both Pd NPs and NHC was confirmed by STEM/EDS and SR-MAS NMR analyses, respectively. This PICB-NHC-Pd catalyst showed excellent activity in the Suzuki–Miyaura coupling reaction without leaching of Pd. Excellent results were obtained in gram-scale synthesis, and catalyst recovery/reuse experiments were completed without loss of catalyst activity.

Novel and efficient consecutive photoredox decarboxylative couplings of adipic acid active esters (bis(1,3-dioxoisoindolin-2-yl)-substituted hexanedioates) with substituted 1-(2-arylethynylsulfonyl)benzenes have been developed under visible-light photocatalysis. The successive photoredox decarboxylative C-C bond formation at room temperature afforded the corresponding cyclic compounds in good yields with tolerance of some functional groups.

A novel and convenient palladium-initiated radical cascade stereoselective iodofluoroalkylation/cycloisomerization of ene-vinylidenecyclopropanes with fluoroalkyl iodides has been developed. The reaction proceeds under mild reaction conditions with high atom economy and stereoselectivity, thereby allowing an efficient access to a variety of difluoromethylated or perfluoroalkylated pyrrolidines tethered with an alkyl iodide. Two plausible radical pathways for the transformation have been proposed on the basis of the results of control experiments and previous reports, which in one case it was thought that palladium(0) was an initiator rather than a catalyst.

Amorphous ZnSb/MgO/C (I) and ZnSb/Al2O3/C (II) nanocomposite anodes are prepared via high-energy ball milling of ZnO and Sb2O3, Mg or Al, and C in molar ratios of 2:1:5 and 6:3:10 under Ar, respectively.