Search

Enhancing electrocatalytic water splitting performance by modulating the intrinsic electronic structure is of great importance. Here, porous bimetallic oxide and chalcogenide nanosheets grown on carbon paper denoted as NiCo2X4/CP (X = O, S, and Se) are prepared to demonstrate how the anion components affect the electronic structures and thereby disclose the correlation between their intermediates interaction and catalytic activities. The experimental characterization and theoretical calculation demonstrate that Se and S substitution can promote the ratio of Co3+/Co2+ and thereby modulate the electronic structure accompanied with the upshift of d band centers, which not only enhance the inner conductivity but also regulate the interaction between the catalyst surface and intermediates, especially for the adsorption of absorbed H and hydroperoxy intermediates towards respective hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). As a result, a full alkaline electrolyzer using NiCo2Se4/CP and NiCo2S4/CP as cathode and anode delivers a low voltage of 1.51 V at 10 mA·cm−2, which is comparable even superior to most transition metal-based electrolyzers.

The membrane fouling is a notorious problem in the practical application of separation membranes. In this study, a mixed matrix membrane based on the MOF BUT-8(A) and the polymer polydiallyldimethylammonium chloride (PDDA) has been prepared on a hydrolyzed polyacrylonitrile (HPAN) substrate by the spin-assisted layer-by-layer assembly (spin-LbL) method. Thanks to the high porosity, high stability, moderate hydrophilicity, and electronegative nature of BUT-8(A), and the good compatibility between BUT-8(A) particles and PDDA polyelectrolytes, the prepared (BUT-8(A)/PDDA)3-HPAN membrane showed high water permeances (over 164 L m−2 h−1 MPa−1) and high rejection rates (over 91.4%) for many dyes in water. Furthermore, the membrane exhibited superior antifouling performance in nanofiltration (NF) with a high flux recovery rate (95.5%) when humic acid (HA) was used as foulant. The high antifouling performance is resulted from tuning hydrophilicity and electronegativity of the membrane surface. These results suggest that the nanofiltration performance of a MOF-based membrane can be well adjusted by a judicious choice of the membrane components and fabrication methods.

The first example of transition-metal catalyzed multicomponent carboannulation of [60]fullerene has been developed. [60]Fullerene, 2-(2,3-allenyl)malonates, and (hetero)aryl iodides undergo a Pd(0)-catalyzed tandem coupling-carboannulation process for regioselective access to novel polysubstituted [60]fullerene-fused cyclopentane derivatives with a wide range of substrate scope and high functional group compatibility. A plausible mechanism involving the formation of a fullerene-π-allylpalladium complex with the characteristic of a fullerene cation as a key intermediate has been proposed.

Reported herein is a new copper-catalyzed N-H/C-H sequential relay oxidative radical carboannulation of [60]fullerene with C2-functionalized free indoles for the direct construction of novel [60]fullerene-fused tetrahydrocyclopenta[

Cu(II)/Mn(III)-mediated synergistic radical N-heteroannulation reaction of [60]fullerene with N-sulfonylated o-amino-arylmalonates has been developed for the direct and efficient construction of [60]fullerene-fused tetrahydroquinoline derivatives. A plausible mechanism for the formation of fullerotetrahydroquinolines is proposed, and the electrochemical properties of the obtained fullerene adducts are investigated.

The first example of metal-free-catalyzed multicomponent annulation reaction of [60]fullerene has been developed for concise and efficient construction of novel [60]fullerene-fused 1,2-tetrahydrocarbazoles. Using inexpensive and readily available I

Herein an unprecedented iron(II)-catalyzed redox-neutral radical cascade reaction of [60]fullerene with γ,δ-unsaturated oxime esters is reported for the preparation of novel free (N-H) pyrrolidino[2',3':1,2]fullerenes. The transformation undergoes an intramolecular cyclization/intermolecular cyclization/oxidation/hydrolysis cascade, and features simple operation, broad substrate scope/high functional group compatibility as well as suitable for scale-up synthesis, providing a facile and practical access to a range of free pyrrolidino[2',3':1,2]fullerenes.

Designing multi-state nonlinear optical (NLO) switch systems has been proposed aiming at the improvement of the multiple storage capacity of the optical memories. However, it is still a challenge to get high first hyperpolarizability (β) contrasts for the molecular second-order NLO switches. In this study, due to their rich electrochemical features, [60]fullerene-fused dihydrocarboline derivatives with a donor (D)–π–acceptor (A) electronic structure were studied for the second-order NLO response and switch effect via different computational approaches. The calculated results showed that significantly high contrasts were displayed on the tot values between the neutral and reduced states. Particularly, the system in which the substituent group was –NO2 had only a calculated βtot value of 0.6 × 10−30 esu, but one-electron reduction enlarged the βtot value to 5689 × 10−30 esu (evaluated at ωB97XD/6-31+G(d) level). Furthermore, the TDDFT calculations demonstrated that the large second-order NLO response of the reduced state resulted from the low energy absorption in the infrared region and the excitation transition from C60 to strong electron-acceptor.

The first umpolung strategy for the cycloacylation of fullerene using a N-heterocyclic carbene organocatalyst is reported. The coupling of [60]fullerene with different structural α,β-unsaturated aldehydes efficiently furnishes interesting [60]fullerene-fused cyclopentan-1-ones or cyclohex-2-en-1-ones in good to excellent yields. This new reaction displays a wide substrate scope and excellent functional-group tolerance, and diverse substituents such as aryl, heteroaryl, alkenyl, alkyl, and ester can be installed by using the corresponding enals.

A highly regioselective iodosulfonylation of allenes in the presence of CuI and 1,10-phenanthroline has been developed for the synthesis of various useful ( E)-α-iodomethyl vinylsulfones in moderate to excellent yields. This practical reaction is fast, operationally simple, and in particular, proceeds under very mild conditions to afford the target products with high regio- and stereoselectivity. The selectivity was illustrated by a conceptual DFT analysis.

A facile and direct intramolecular oxidative C(aryl)-H amidation reaction was developed for the synthesis of quinolino[3,4-b]quinoxalin-6(5H)-ones in moderate to excellent yields starting from readily available materials by tethering the adjacent N-methoxyamide and aryl portions in the presence of phenyliodine(III) bis(trifluoroacetate) at room temperature. This metal-free approach is a valuable addition to the traditional methods already available for the preparation of these molecules.

The unique reactivity and synthetic applications of oxime acetate derivatives with N, O and S-substituent at the α-position are disclosed for the first time, which leads to 2-substituted fulleropyrrolidines and mono- and disubstituted 1-fulleropyrrolines via copper-catalyzed redox-neutral N-heteroannulation reactions with C60. This transformation is operationally simple and has a broad substrate scope and good functional-group tolerance. Theoretical calculations at the level of B3LYP/6-31G(d) were performed to elucidate the chemoselectivity of the reaction.

A mild and efficient method for the synthesis of thiosulfonates has been developed through CuI-catalyzed reductive coupling of arenesulfonyl chlorides using Na2SO3 or NaHSO3 as the terminal reductant under nitrogen atmosphere at room temperature. A broad scope of thiosulfonates were obtained in high to excellent yields in this simple, practical and economical transformation. The ease of handling, being performed at room temperature, use of low-cost and readily available reaction materials, and the efficiency at kilo-scale make this simple and practical method attractive in both organic synthesis and industrial applications.

A facile and direct oxidative reaction for the synthesis of vicinal tricarbonyl amides in moderate to excellent yields (53-88%) was developed starting from readily available β-ketoamides in the presence of phenyliodine(III) bis(trifluoroacetate). The resulting products possess significant synthetic potential, making this approach a valuable addition to the group of traditional methods already available for the preparation of these molecules.

An efficient ring-closing reaction was developed for the synthesis of spirocyclopropane quinolinediones from 2,2-disubstituted 2-benzoylacetamides in the presence of [bis-(trifluoroacetoxy)iodo]benzene (PIFA). This reaction proceeds at room temperature in the absence of a metal catalyst to provide spirocyclopropane quinolinediones in good to excellent yields. Furthermore, these compounds were readily converted to the corresponding pyrrolo[3,2-c]quinolinones to provide tricyclic ring structures similar to those found in the natural products martinellic acid and martinelline via an intermolecular amine ring-opening cyclization reaction.

A new, operationally simple one-pot method has been developed for the regioselective synthesis of a series of novel 4-olefinated dihydropyridines bearing various functional groups from the reaction of pyridine, acylacetamides, and sulfuryl chlorides under mild conditions. In this multicomponent process, subsequent the activation of pyridine by sulfuryl chloride/nucleophilic addition of acylacetonitrile formed in situ/enolization/sulfonylation leads to the formation of final products.

An efficient copper(I)-catalysed intramolecular arylmethyl C(sp3)–H direct oxidative amidation reaction has been developed for the preparation of drug-like 1H-pyrrolo[3,4-b]quinoline-1,3(2H)-diones from readily available 2-methyl-3-carbamoyl-quinolines.

An efficient tandem copper(I)-catalyzed intramolecular allylic C(sp 3 )–H functionalization/C–N formation/oxidative reaction of 6-methyl-dihydropyrimidine-2-one-5-carboxamides has been developed for the synthesis of substituted 2 H -pyrrolo[3,4- d ]pyrimidine-2,5,7(3 H ,6 H )-trione derivatives in a single step in good to excellent yields.

To achieve direct conversion of lignocellulosic biomass to electricity, electron transfer chains (ETCs) were constructed with organic redox compounds and ferric ions as the anode and cathode electron carriers, respectively. Methylene blue (MB) was screened as a promising anode electron carrier with good redox properties and being capable of efficiently working under both acidic and alkaline conditions. Acid or alkali electrolyte played important roles in depolymerization of cellulose and lignin, as well as the deconstruction of biomass (wheat straw) cell wall; however, the presence of MB well facilitated the degradation of cellulose and solublization of wheat straw polymeric components. The reduced MB (MBH) could be well re-oxidized and discharged in a liquid-flow fuel cell (LFFC). The highest out-put power densities (Pmax) of the LFFC under acidic and alkali conditions reached 12.3 and 41.8 mW/cm2 with open circuit voltages of 560 and 1560 mV, respectively.

The performance of mixed matrix membranes (MMMs) is usually limited by thick separation layer, low filler loading, and boundary defect between polymer and filler. Herein, a new two-dimensional metal-organic framework (2D MOF), named BUT-203, is designed and synthesized. Remarkably, the micron-sized crystals of this MOF could be readily delaminated into nanosheets with thickness of ca. 3 nm and lateral size of hundreds of nanometers to several microns. This delaminated nanosheets with high dispersibility in ethanol have a good compatibility with the polycation polymer polyethyleneimine (PEI). Under the optimum condition, a thin (ca. 70 nm) and high filler loading (up to ca. 73%) MMM, named BUT-203/PEI-HPAN(73) can be fabricated on macroporous hydrolyzed polyacrylonitrile (HPAN) substrate by a simple blending-spin coating method. This membrane shows a high water permeance up to 870 L/(m2·h·MPa) and high rejections (over 97.9%) for anionic dye molecules. In addition, this membrane exhibits a long term running stability, high dye desalination ability, and excellent antifouling property. These results suggest the usefulness of the membrane in nanofiltration, and simultaneously this work demonstrates that rationally designed 2D MOFs have great potential as filler materials in fabricating MMMs for various applications.

Described here is the first example of solvent-promoted catalyst-free N-incorporation multicomponent domino reaction for the direct construction of novel π-extension [60]fullerene-fused dihydrocarbolines from simple hydrocarbons. This unprecedented transformation is proposed to proceed by a sequential N-incorporation/[4+2] cycloaddition/elimination process, involving multiple types of bond cleavage and formation in a single chemical operation. Mechanistic studies uncover that solvent is crucial for the success of the transformation, and multiple solvent-aided deprotonation and proton transfer are involved as key steps.

An efficient and practical method for the synthesis of medicinally important acridines from readily available o-aminoaryl ketones and arylboronic acids was developed using copper(II)-mediated relay reactions that involve intermolecular Chan–Lam cross-coupling and subsequent intramolecular Friedel–Crafts-type reactions. A sole promoter, i.e., Cu(OTf)2, was used; therefore, strongly acidic and basic conditions, nonreadily available or expensive substrates, additives, and noble-metal catalysts were not needed.

The reaction of o-aminoacetophenones and arylboronic acids catalyzed by copper(II) salts in the presence of pyridine under an O2 atmosphere provides a general and efficient one-pot preparation of biologically interesting acridones. This relay reaction comprises an intermolecular Suzuki cross-coupling, intramolecular oxidative C(sp3)–H amination, and C(sp2)–H activation with simultaneous rearrangement of the generated isatin intermediates. This strategy tolerates both electron-donating and -withdrawing functionalities to afford various acridones in good to excellent yields.

An intramolecular copper-catalyzed direct C(sp2)–H activation/C(sp2)–N bond formation reaction has been developed for the synthesis of pyrrolo[3,2-c]quinolinone derivatives under an oxygen atmosphere. This approach presents an alternative route to the tricyclic core of martinellic acid or martinelline.

A novel Ag(I)-induced three-component annulation reaction of [60]fullerene with sulfonylhydrazones and nitriles has been developed for the efficient synthesis of diverse disubstituted [60]fullerene-fused dihydropyrroles. The reaction exhibits a broad substrate scope and excellent functional-group tolerance, and also allows for the synthesis of fullerene-bound macromolecules.

A highly selective, IBX-promoted reaction has been developed for the oxidative cleavage of inert C(aryl)–N bonds on secondary amides while leaving the C(carbonyl)–N bond unchanged. This metal-free reaction proceeds under mild conditions (HFIP/H2O, 25 °C), providing facile access to various useful primary amides, some of which would be otherwise unattainable using conventional aminolysis and hydrolysis approaches.

A novel and efficient Cu(I)/Ag(I)-mediated synergistic annulation reaction of [60]fullerene with diarylethanones, benzoylacetonitriles, and β-dicarbonyl compounds has been developed for the direct construction of diverse disubstituted dihydrofuran-fused [60]fullerene derivatives. This transformation exhibits a remarkably broad substrate scope and functional group tolerance and provides a useful method to a scarce class of fullerene derivatives.

A novel in situ generated TEMPO oxoammonium salt mediated one-pot tandem reaction has been developed for the straightforward construction of pyrrolin-4-ones from readily available β-oxoamides with amine hydrochlorides. The reaction tolerates various functional groups and represents a reliable method for the synthesis of highly substituted pyrrolin-4-ones in good yields under mild conditions. Detailed mechanistic studies disclosed that TEMPO oxoammonium salt generated in situ was crucial for the transformation involving the formation of enaminone precursors in situ by condensation of the β-oxoamides with amines, followed by sequential oxidative coupling with β-oxoamides, intramolecular cyclization, and 1,2-alkyl migration steps.

Invariant natural killer T-cells (iNKT-cells) are promising targets for manipulating the immune system, which can rapidly release a large amount of Th1 and Th2 cytokines upon the engagement of their T cell receptor with glycolipid antigens presented by CD1d. In this paper, we wish to report a novel series of α-GalCer analogues which were synthesized by incorporation of l -amino acid methyl esters in the C-6′ position of glycolipid. The evaluation of these synthetic analogues for their capacities to stimulate iNKT-cells into producing Th1 and Th2 cytokines both in vitro and in vivo indicated that they were potent CD1d ligands and could stimulate murine spleen cells into a higher release of the Th1 cytokine IFN-γ in vitro. In vivo, Gly-α-GalCer (1) and Lys-α-GalCer (3) showed more Th1-biased responses than α-GalCer, especially analogue 3 showed the highest selectivity for IFN-γ production (IFN-γ/IL-4 = 5.32) compared with α-GalCer (IFN-γ/IL-4 = 2.5) in vivo. These novel α-GalCer analogues might be used as efficient X-ray crystallographic probes to reveal the relationship between glycolipids and CD1d proteins in α-GalCer/CD1d complexes and pave the way for developing new potent immunostimulating agents.

A transition-metal-free oxidative dehydrogenative coupling reaction has been developed for the direct construction of novel C60-fused tetrahydrocarbazoles, dibenzothiophenes, benzothiophenes, and dibenzofurans. This new carboannulation reaction features high atom economy, operational simplicity, broad substrate scope, and excellent functional-group tolerance and provides a convenient access to a scarce class of fullerene derivatives.