Electrochemically Promoted Asymmetric Transfer Hydrogenation of 2,2,2-Trifluoroacetophenone.

The study reported an electrochemically promoted asymmetric hydrogen transfer reaction of 2,2,2-trifluoroacetophenone with a chiral Ru complex. (R)-α-(Trifluoromethyl) benzyl alcohol with a 96% yield and 94% ee could be obtained with only a 0.5 F mol-1 charge amount at room temperature and normal pressure.

Novel tetranuclear grid-like Zn(II) complexes derived from dihydrazone pyrimidine derivatives as antitumor agents.

Due to the antitumor properties, Zn(II) complexes have attracted more and more attention. Herein, three novel tetranuclear Zn(II) complexes 1-3 based on dihydrazone pyrimidine derivatives H2L1-H2L3 were synthesized and characterized using IR spectroscopy, 1H NMR spectroscopy, single crystal X-ray diffraction analysis, XRD, TG and elemental analysis. Single crystal X-ray diffraction analysis revealed that 1-3 all displayed a [2 × 2] grid-like topology. The stability in solution, lipophilicity, confocal imaging and antitumor activities were investigated. Complexes 1-3 displayed high structural stability, membrane permeability and different lipophilicities. They can target mitochondria due to the cation charge. The MTT assay indicated that all of them exhibited stronger antiproliferative activity than the corresponding derivatives H2L1-H2L3 and the well-known cisplatin against all the selected tumor cells (BGC-823, BEL-7402, MCF-7 and A549), with IC50 values ranging from 2.83 µM to 7.97 µM. AO/EB double staining, flow cytometry and ROS detection suggested that complexes 1 and 2 could induce BGC-823 apoptosis in a dose-dependent manner. UV-Vis spectra, CD spectra, viscosity analysis and molecular docking revealed that complexes 1 and 2 interact with DNA mainly via partial intercalation and groove binding. Tetranuclear [2 × 2] grid-like Zn(II) complexes have the potential to be promising antitumor agents in the future.

A near-infrared fluorescent probe for the detection of Cu2+ in Chinese herbal medicine and imaging in living cells.

Copper is one of the common among the heavy metal pollution in Chinese herbal medicine (CHM). So, it is essential to develop rapid and accurate testing method to quantify the Cu2+ content in CHM. Herein, we prepared a coordination-based near-infrared fluorescent probe (NRh6G-FA) by introducing a hemicyanine dye in rhodamine 6G scaffold. NRh6G-FA had a high sensitivity, anti-interference performance, fast response (within 60 s), visualization (from light yellow to green) for Cu2+ and excellent sensing performance for the detection of Cu2+ at low concentrations (LOD = 0.225 µM). The most likely mechanism was verified on the basis of Job's plot, ESI-HRMS and DFT calculations. NRh6G-FA could be successfully applied for the detection and "naked eye" recognition of Cu2+ in CHM samples. Moreover, NRh6G-FA was used to visualize Cu2+ in living MCF-7 cells by confocal fluorescence imaging.

Remarkable sensitivity of the electrochemical reduction of benzophenone to proton availability in ionic liquids.

The reduction of benzophenone was investigated in five different ionic liquids by using transient cyclic voltammetry, near steady-state voltammetry, and numerical simulation. Two reversible, well-resolved one-electron-reduction processes were observed in dry (≤20 ppm water, ca. 1 mM)) 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Bmpyrd][NTf(2)]) and 1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide ([Bmpipd][NTf(2)]), which did not contain any readily available proton source. Upon addition of water, the second process became chemically irreversible and shifted to a more positive potential by approximately 600 mV; moreover, the two reduction processes merged into a single two-electron proton-coupled process when about 0.6 M H(2)O was present. This large dependence of potential on water content, which was not observed in molecular solvents (electrolyte), was explained by a reaction mechanism that incorporated protonation and hydrogen-bonding interactions of the benzophenone dianion with as many as seven water molecules. In the three imidazolium-based ionic liquids used herein, the first benzophenone-reduction process was again reversible, whilst the second reduction process became chemically irreversible owing to the availability of the C2-H imidazolium protons in these ionic liquids. The reversible potentials for benzophenone reduction were remarkably independent of the identity of the ionic liquids, thereby implying either weak interactions with the ionic liquids or relatively insignificant differences in the levels of ion-pairing. Thus, the magnitude of the separation of the potentials of the reversible first and irreversible second reduction processes mainly reflected the proton availability from either the ionic liquid itself or from adventitious water. Consequently, voltammetric reduction of benzophenone provides a sensitive tool for the determination of proton availability in ionic liquids.

Nitrogen-doped mesoporous carbon supported CuSb for electroreduction of CO2.

The construction of an efficient catalyst for electrocatalytic reduction of CO2 to high value-added fuels has received extensive attention. Herein, nitrogen-doped mesoporous carbon (NMC) was used to support CuSb to prepare a series of materials for electrocatalytic reduction of CO2 to CH4. The catalytic activity of the composites was significantly improved compared with that of Cu/NMC. In addition, the Cu content also influenced the activity of electrocatalytic CO2 reduction reaction. Among the materials used, the CuSb/NMC-2 (Cu: 5.9 wt%, Sb: 0.49 wt%) catalyst exhibited the best performance for electrocatalytic CO2 reduction, and the faradaic efficiency of CH4 reached 35%, and the total faradaic efficiency of C1-C2 products reached 67%.

Brushable Lubricant-Infused Porous Coating with Enhanced Stability by One-Step Phase Separation.

Slippery lubricant-infused porous surface (SLIPS) is a promising solution to undesired adhesion. Unfortunately, the complicated fabrication process and limited coating area block its practical applications. Herein, we report a one-step strategy to fabricate polypropylene-based SLIPS coatings through thermally induced phase separation, in which the lubricant is in situ infiltrated within a polymer network formed during cooling. The solid-liquid-phase separation process was monitored by an in situ hot-stage microscope. Such coating performs outstanding self-cleaning, anti-corrosion, and anti-bacterial performance, as well as enhanced stability of the lubricant layer because the lubricant is well adapted in the structure.

Atomically Dispersed Copper on N-Doped Carbon Nanosheets for Electrocatalytic Synthesis of Carbamates from CO2 as a C1 Source.

The synthesis of carbamates by electrocatalytic reduction of CO2 is an effective method to realize the utilization of CO2 resources. The development of high-performance electrocatalysts to complete this process more efficiently is of great significance to sustainable development. Owing to their unique structural characteristics, single-atom catalysts are expected to promote the reaction process more efficiently. In this study, an atomically dispersed Cu species on N-doped carbon nanosheet composite material (Cu-N-C) was prepared by metal-organic framework derivatization. Compared with traditional Cu bulk electrodes, the Cu-N-C material has better catalytic performance for the synthesis of methyl N-phenylcarbamate; and the optimized yield reached 71 % at room temperature and normal pressure. The Cu-N-C material has good stability that the catalytic performance does not decrease after repeated use for 10 times. In addition, the Cu-N-C material has good applicability to this catalytic system, and a variety of amines can be smoothly converted into corresponding carbamates.

Electrocatalytic carboxylation of halogenated compounds with mesoporous silver electrode materials.

Mesoporous silver materials are used as electrocatalysts for halogenated compounds. The mesoporous silver materials have uniform mesoporous size (8 nm), large specific surface area (12 m2 g-1), high pore volume (0.07 cm3 g-1), and a good 3D network structure of the metallic silver skeleton. The results show that the prepared materials exhibit high performance in electrocatalytic carboxylation of halogenated compounds to acid (78%).

Ordered Mesoporous Carbon Embedded with Cu Nanoparticle Materials for Electrocatalytic Synthesis of Benzyl Methyl Carbonate from Benzyl Alcohol and Carbon Dioxide.

We prepared a series of ordered mesoporous carbons embedded with different contents of Cu nanoparticles (Cu/OMC-X) and applied them to electrocatalytic synthesis of benzyl methyl carbonate. The materials were characterized by many measurements, which showed that Cu/OMC-X materials maintain highly ordered mesoporous structures with high surface area and highly dispersed Cu nanoparticles. As expected, the materials exhibit good electrocatalytic performance. The optimal yield of benzyl methyl carbonate reaches 69.7% on Cu/OMC-3.

Synthesis of Ag nanoparticles/ordered mesoporous carbon as a highly efficient catalyst for the electroreduction of benzyl bromide.

To develop efficient catalysts for the electroreduction of organic halides, a facile one-pot synthesis of Ag nanoparticles/ordered mesoporous carbon electrode materials via the self-assembly of CH3COOAg and resol in the presence of triblock copolymer is proposed. The resultant electrode materials possess uniform mesopore sizes (3.3 nm) and pore volumes (∼0.28 cm3 g-1), high specific surface areas (∼500 m2 g-1), and uniformly dispersed Ag nanoparticles (12-36 nm) loaded within the carbon matrix. Cyclic voltammetry, measurements of electrochemically active surface area, and electrolysis experiments were conducted to understand the correlations between the catalytic ability and the structural and textural features of the catalysts. Excellent bibenzyl yield (98%) and remarkable reusability were obtained under mild conditions. The results confirm that the prepared nanocomposites show outstanding performance in the electroreduction degradation of PhCH2Br to bibenzyl.

Electrochemical study of dialcarb "distillable" room-temperature ionic liquids.

Electrode-dependent potential windows (see picture, GC=glassy carbon) are determined for five dialkylammonium carbamate (dialcarb) room-temperature ionic liquids in a systematic study of their physical and electrochemical properties. The viscosity and conductivity of the dialcarb ionic liquids, which are "distillable" at low temperature, are comparable to those of some conventional room-temperature ionic liquids. The physical and electrochemical properties of five "distillable" room-temperature ionic liquids from the dialcarb family (dialkylammonium carbamates formed from CO(2) and dialkyl amines) are systematically investigated. In particular dimethyl (DIMCARB), diethyl (DIECARB), dipropyl (DIPCARB), methylethyl (MEETCARB), and methylpropyl (MEPRCARB) carbamate ionic liquids are studied. The temperature dependence of the viscosity and conductivity of MEETCARB exhibit an Arrhenius-type relationship. Except for DIPCARB, which has too high a resistance, a reference potential scale is available by using the IUPAC recommended redox system, that is the cobalticenium/cobaltocene (Cc(+)/Cc) process, which exhibits an ideal reversible voltammetric response. Oxidation of decamethylferrocene, but not ferrocene, also is ideal in DIMCARB, DIECARB, MEETCARB, and MEPRCARB. The magnitudes of the potential windows of the electrochemically viable dialcarbs are investigated and follow the order of glassy carbon>Au>Pt>Hg. Diffusion coefficients of Cc(+), DmFc, and double-layer capacitance values are compared in each dialcarb. Despite the considerable viscosity of the dialcarbs, steady-state voltammetric behavior is achieved at a rotating disk electrode for rotation rates of 1000 rpm or higher.

Silver encapsulated copper salen complex: efficient catalyst for electrocarboxylation of cinnamyl chloride with CO2.

An active catalyst, [Cu]@Ag composite, was synthesized for the first time and used as a cathode for electrocarboxylation of cinnamyl chloride with CO2. ß,γ-Unsaturated carboxylic acids were obtained with excellent yield and moderate selectivity. Moreover, reasonable yields and selectivities of carboxylic acids were also achieved with several allylic halides and aryl halides.

One-Pot Synthesis of d-Phenylalanine-Functionalized Multiwalled Carbon Nanotubes: A Metal-Free Chiral Material for the Asymmetric Electroreduction of Aromatic Ketones.

A simple protocol to synthesize d-phenylalanine (d-PHE)-functionalized multiwalled carbon nanotubes (MWCNTs) via the one-pot method was established by grafting d-PHE onto MWCNTs to obtain d-PHE-MWCNTs under mild reaction conditions. The resulting d-PHE-MWCNTs were characterized in detail via spectroscopy and surface analysis. The electroreduction of 2,2,2-trifluoroacetophenone at the d-PHE-MWCNTs cathode afforded ( S)-α-(trifluoromethyl) benzyl alcohol whose yield was 65% and the enantiomeric excess was 40%. No extra catalysts were required in this electrochemical reaction solution compared with other reactions requiring homogeneous catalysis. The metal-free chiral material also showed acceptable asymmetric electroreduction performance, considerable stability, and favorable reusability.

One-pot synthesis of Ni nanoparticle/ordered mesoporous carbon composite electrode materials for electrocatalytic reduction of aromatic ketones.

A simple one-pot synthesis of Ni nanoparticle/ordered mesoporous carbon composite electrode materials is demonstrated for electrosynthesis for the first time. The obtained nanocomposites have uniform mesopore sizes (3.0-3.7 nm), large specific surface areas (506-633 m2 g-1), high pore volumes (0.28-0.38 cm3 g-1), well-graphitized carbon frameworks, and uniformly dispersed Ni nanoparticles (7-15 nm) embedded in the carbon pore walls. The prepared materials show very high performance in the selective (∼84%) electrocatalytic reduction of aromatic ketones into alcohols (∼79%).

Entrapment of a chiral cobalt complex within silver: a novel heterogeneous catalyst for asymmetric carboxylation of benzyl bromides with CO2.

A novel way to accommodate heterogeneous catalysis, CO2 fixation and asymmetric synthesis on one catalyst is reported. The [Co]@Ag composite was prepared for the first time and used for asymmetric carboxylation of benzyl bromides with CO2. All the procedures were performed under mild conditions. Moreover, the [Co]@Ag composite has terrific stability and reusability.