Fabrication of In-rich AgInS<Subscript>2</Subscript> nanoplates and nanotubes by a facile low-temperature co-precipitation strategy and their excellent visible-light photocatalytic mineralization performance

Visible-light-driven In-rich AgInS₂ nanoplates and nanotubes were successfully prepared by a convenient co-precipitation strategy at low temperature. The effect of different In/Ag molar ratio in the raw materials on the physicochemical properties and photocatalytic activity of AgInS₂ was investigated. The In/Ag molar ratio has an obvious effect on the morphology of AgInS₂, and the physicochemical properties and photocatalytic activity of AgInS₂ are also dependent on the In/Ag molar ratio. When the molar ratio of In/Ag is 9, the photoluminescence intensity of AgInS₂ reaches a minimum value, while its photocurrent density is maximum (0.011 mA/cm²), indicating the most efficient separation of electron-hole pairs. The AgInS₂ with the In/Ag molar ratio of 9 exhibits the highest visible-light photocatalytic activities with almost complete degradation of 2-nitrophenol, which is attributed to the narrowest band gap and the most efficient separation of electron-hole pairs. Moreover, In-rich AgInS₂ exhibits excellent regeneration ability.     

Effect of optical purity on the critical heat capacity at the smectic-A-(chiral)-smectic-C transition in an antiferroelectric liquid crystal

High resolution ac calorimetric measurements have been carried out near the smectic-A-chiral-smectic-C phase transition in the antiferroelectric liquid crystal 4-(1-methylheptyloxycarbonyl)phenyl 4(')-octyloxybiphenyl-4-carboxylate (MHPOBC). Data on samples with different optical purities have been analyzed in detail using a renormalization-group expression with corrections-to-scaling terms. The chiral-smectic-C(alpha)-chiral-smectic-C phase transition is first order, while the smectic-A-chiral-smectic-C(alpha) phase transition is second order. A direct smectic-A-chiral-smectic-C phase transition, which occurs in near-racemic mixtures, was found to be quasitricritical and weakly first order. This implies that the smectic-A-smectic-C transition in the racemate locates at a special point where four critical lines intersect.     

Evaluation of Quality,Antioxidant Capacity,and Digestibility of Chickpea (Cicer arietinum L. cv Blanoro) Stored under N2 and CO2 Atmospheres

The aim of this work was to monitor the quality, antioxidant capacity and digestibility of chickpea exposed to different modified atmospheres. Chickpea quality (proximal analysis, color, texture, and water absorption) and the antioxidant capacity of free, conjugated, and bound phenol fractions obtained from raw and cooked chickpea, were determined. Cooked chickpea was exposed to N₂ and CO₂ atmospheres for 0, 25, and 50 days, and the antioxidant capacity was analyzed by DPPH (2,2′-diphenyl-1-picrylhydrazyl), ABTS (2,2′-azino-bis-[3ethylbenzothiazoline-6-sulfonic acid]), and total phenols. After in vitro digestion, the antioxidant capacity was measured by DPPH, ABTS, FRAP (ferric reducing antioxidant power), and AAPH (2,2′-Azobis [2-methylpropionamidine]). Additionally, quantification of total phenols, and UPLC-MS profile were determined. The results indicated that this grain contain high quality and high protein (18.38%). Bound phenolic compounds showed the highest amount (105.6 mg GAE/100 g) and the highest antioxidant capacity in all techniques. Cooked chickpeas maintained their quality and antioxidant capacity during 50 days of storage at 4 and −20 °C under a nitrogen atmosphere. Free and conjugated phenolic compounds could be hydrolyzed by digestive enzymes, increasing their bioaccessibility and their antioxidant capacity during each step of digestion. The majority compound in all samples was enterodiol, prevailing the flavonoid type in the rest of the identified compounds. Chickpea contains biological interest compounds with antioxidant potential suggesting that this legume can be exploited for various technologies.     

DAMQT 2.1.0: A new version of the DAMQT package enabled with the topographical analysis of electron density and electrostatic potential in molecules

DAMQT‐2.1.0 is a new version of DAMQT package which includes topographical analysis of molecular electron density (MED) and molecular electrostatic potential (MESP), such as mapping of critical points (CPs), creating molecular graphs, and atomic basins. Mapping of CPs is assisted with algorithmic determination of Euler characteristic in order to provide a necessary condition for locating all possible CPs. Apart from the mapping of CPs and determination of molecular graphs, the construction of MESP‐based atomic basin is a new and exclusive feature introduced in DAMQT‐2.1.0. The GUI in DAMQT provides a user‐friendly interface to run the code and visualize the final outputs. MPI libraries have been implemented for all the tasks to develop the parallel version of the software. Almost linear scaling of computational time is achieved with the increasing number of processors while performing various aspects of topography. A brief discussion of molecular graph and atomic basin is provided in the current article highlighting their chemical importance. Appropriate example sets have been presented for demonstrating the functions and efficiency of the code. © 2015 Wiley Periodicals, Inc.     

Bifunctional Catalysts Based on m‐Phenylene‐Bridged Porphyrin Dimer and Trimer Platforms: Synthesis of Cyclic Carbonates from Carbon Dioxide and Epoxides

Highly active bifunctional diporphyrin and triporphyrin catalysts were synthesized through Stille coupling reactions. As compared with a porphyrin monomer, both exhibited improved catalytic activities for the reaction of CO₂ with epoxides to form cyclic carbonates, because of the multiple catalytic sites which cooperatively activate the epoxide. Catalytic activities were carefully investigated by controlling temperature, reaction time, and catalyst loading, and very high turnover number and turnover frequency were obtained: 220 000 and 46 000 h^?1, respectively, for the magnesium catalyst, and 310 000 and 40 000 h^?1, respectively, for the zinc catalyst. Results obtained with a zinc/free‐base hybrid diporphyrin catalyst demonstrated that the Br^? ions on the adjacent porphyrin moiety also function as nucleophiles.     

Highly enantioselective and efficient synthesis of methyl (R)-o-chloromandelate with recombinant E. coli: toward practical and green access to clopidogrel

Methyl (R)-o-chloromandelate ((R)-), which is an intermediate for a platelet aggregation inhibitor named clopidogrel, was obtained in >99% ee by the asymmetric reduction of methyl o-chlorobenzoylformate (2) (up to 1.0 M) with recombinant E. coli overproducing a versatile carbonyl reductase.     

Generation of basis sets with high degree of fulfillment of the Hellmann-Feynman theorem

A direct relationship is established between the degree of fulfillment of the Hellman-Feynman (electrostatic) theorem, measured as the difference between energy derivatives and electrostatic forces, and the stability of the basis set, measured from the indices that characterize the distance of the space generated by the basis functions to the space of their derivatives with respect to the nuclear coordinates. On the basis of this relationship, a criterion for obtaining basis sets of moderate size with a high degree of fulfillment of the theorem is proposed. As an illustrative application, previously reported Slater basis sets are extended by using this criterion. The resulting augmented basis sets are tested on several molecules finding that the differences between energy gradient and electrostatic forces are reduced by at least one order of magnitude.     

Stability of Cocaine,Opiates, and Metabolites in Dried Saliva Spots

Drug abuse still represents a global problem, and it is associated with an increased risk of diseases, injuries, and deaths. Cocaine (COC) and opiates are the most abused drugs and account for a significant number of fatalities. Therefore, it is important to develop methods capable of effectively identifying and quantifying these substances. The present study aims to evaluate the long-term stability of COC, ecgonine methylester (EME), benzoylecgonine (BEG), cocaethylene (COET), norcocaine (NCOC), morphine (MOR), codeine (COD) and 6-monoacetylmorphine (6-MAM) in oral fluid samples. The analytes of interest were isolated from the matrix (50 µL) using the dried saliva spots (DSS) sampling approach and were subsequently analyzed by gas chromatography coupled with tandem mass spectrometry (GC–MS/MS). The parameters that could influence the stability of the target compounds were studied, and these were storage temperature, light, use of preservatives (and respective concentrations), and time. The effects of each parameter were evaluated using the design of experiments (DOE) approach. The stability of the target analytes was improved when the DSS were stored at room temperature, in the presence of light and using 1% sodium fluoride. The best conditions were then adopted for the DSS storage and long-term stability was assessed. COD was only stable for 1 day, EME was stable for 3 days, COC, COET, NCOC and 6-MAM were stable for 7 days, MOR for 14 days and BEG remained stable throughout the study (136 days). This is the first study that evaluates the stability of these compounds in oral fluid samples after application in DSS cards, and optimizes the conditions in order to improve their stability.     

Water as a monomer: synthesis of an aliphatic polyethersulfone from divinyl sulfone and water

Using water as a monomer in polymerization reactions presents a unique and exquisite strategy towards more sustainable chemistry. Herein, the feasibility thereof is demonstrated by the introduction of the oxa-Michael polyaddition of water and divinyl sulfone. Upon nucleophilic or base catalysis, the corresponding aliphatic polyethersulfone is obtained in an interfacial polymerization at room temperature in high yield (>97%) within an hour. The polyethersulfone is characterized by relatively high molar mass averages and a dispersity around 2.5. The polymer was tested as a solid polymer electrolyte with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as the salt. Free-standing amorphous membranes were prepared by a melt process in a solvent-free manner. The polymer electrolyte containing 15 wt% LiTFSI featured an oxidative stability of up to 5.5 V vs. Li/Li⁺ at 45 °C and a conductivity of 1.45 × 10⁻⁸ S cm⁻¹ at room temperature.

This study describes the first example of the polymerization of water as one of two monomers. The obtained polymer allows for a solvent-free preparation of polymer electrolyte membranes exhibiting a high oxidative stability.     

Aggregation-Induced Circularly Polarized Luminescence from Boron Complexes with a Carbazolyl Schiff Base

A variety of carbazolyl-appended Schiff bases were readily synthesized from 1-formylcarbazoles and aniline derivatives. Boron complexation of the resulting ligands allowed for facile preparation of new carbazole-based BODIPY analogues showing solid-state fluorescence. Furthermore, some dyes were converted into chiral compounds through the Et₂AlCl-mediated incorporation of a binaphthyl unit. The chiral dyes showed aggregation-induced fluorescence and circularly polarized luminescence (CPL) with the Φ_F and g_lum of up to 0.22 and −3.5×10⁻³, respectively, in the solid state. The solid-state fluorescence and CPL were well characterized by the crystal packing analyses and DFT calculations.