Kinetics and mechanism of triclocarban degradation by the chlorination process: Theoretical calculation and experimental verification.

Triclocarban (TCC) is an antimicrobial agent commonly used in many household and personal care products, and has been found persistent in the aquatic environment. Here we elucidate the kinetics and mechanism of TCC degradation during chlorination process by density functional theory (DFT) calculation and experimental verification. Results showed that hypochlorous acid (HOCl)/hypochlorite (OCl) reacted with TCC via Cl-substitution, OH-substitution and C-N bond cleavage pathways.

Revisiting photocyclization of the donor-acceptor stenhouse adduct: missing pieces in the mechanistic jigsaw discovered.

Donor-acceptor Stenhouse adducts (DASA) have recently emerged as a class of visible-light-induced photochromic molecular switches, but their photocyclization mechanism remains puzzling and incomplete. In this work, we carried out MS-CASPT2//SA-CASSCF calculations to reveal the complete mechanism of the dominant channels and possible side reactions. We found that a new thermal-then-photo isomerization channel, , EEZ → EZZ → EZE, other than the commonly accepted EEZ → EEE → EZE channel, is dominant in the initial step.

A novel all-nitrogen molecular crystal N as a promising high-energy-density material.

All-nitrogen solids, if successfully synthesized, are ideal high-energy-density materials because they store a great amount of energy and produce only harmless N gas upon decomposition. Currently, the only method to obtain all-nitrogen solids is to apply high pressure to N crystals. However, products such as cg-N tend to decompose upon releasing the pressure.

Kinetics and Mechanism of Degradation of Reactive Radical-Mediated Probe Compounds by the UV/Chlorine Process: Theoretical Calculation and Experimental Verification.

The UV/chlorine process, by combining chlorination with UV irradiation, has been recently considered as a highly efficient advanced oxidation process (AOP) technology in water treatment. Nitrobenzene (NB), benzoic acid (BA), and -chlorobenzoic acid (CBA) are widely used as model probe compounds in the UV/chlorine system to calculate the second-order rate constants of the specific radical reaction with target contaminates by a competitive kinetics method. A comprehensive understanding of probe compounds' reaction mechanism with reactive radicals is critical for investigation of the UV/chlorine reaction system.

Degradation pathways of penthiopyrad by δ-MnO mediated processes: a combined density functional theory and experimental study.

Penthiopyrad is a widely used succinate dehydrogenase inhibitor (SDHI) fungicide and frequently detected in natural environments. In order to better understand its fate in natural systems, the degradation of penthiopyrad by manganese dioxide (MnO) was investigated in this study. The results show that penthiopyrad is rapidly degraded in the δ-MnO system.

Cobalt(II)-Catalyzed [4+2] Annulation of Picolinamides with Alkynes via C-H Bond Activation.

A cobalt(II)-catalyzed [4+2] annulation of picolinamides with alkynes via C-H bond activation has been developed. The operationally simple annulation reaction allows for the synthesis of acyl-substituted 1H-benzoquinoline bearing multiple aromatic rings (up to 96 % yield) without co-oxidant or other oxidation factors under mild conditions. Several control experiments were carried out.

Predicting the Feasibility of Copper(I)-Catalyzed Alkyne-Azide Cycloaddition Reactions Using a Recurrent Neural Network with a Self-Attention Mechanism.

The copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) reaction, a major click chemistry reaction, is widely employed in drug discovery and chemical biology. However, the success rate of the CuAAC reaction is not satisfactory as expected, and in order to improve its performance, we developed a recurrent neural network (RNN) model to predict its feasibility. First, we designed and synthesized a structurally diverse library of 700 compounds with the CuAAC reaction to obtain experimental data.

Nano-makisu: highly anisotropic two-dimensional carbon allotropes made by weaving together nanotubes.

Graphene and carbon nanotubes (CNT) are the representatives of two-dimensional (2D) and one-dimensional (1D) forms of carbon, both exhibiting unique geometric structures and peculiar physical and chemical properties. Herein, we propose a family or series of 2D carbon-based highly anisotropic Dirac materials by weaving together an array of CNTs by direct C-C bonds or by graphene ribbons. By employing first-principles calculations, we demonstrate that these nano-makisus are thermally and dynamically stable and possess unique electronic properties.

Side-Chain Polymers as Dopant-Free Hole-Transporting Materials for Perovskite Solar Cells-The Impact of Substituents' Positions in Carbazole on Device Performance.

Side-chain polymers have the potential to be excellent dopant-free hole-transporting materials (HTMs) for perovskite solar cells (PSCs) because of their unique characteristics, such as tunable energy levels, high charge mobility, good solubility, and excellent film-forming ability. However, there has been less research focusing on side-chain polymers for PSCs. Here, two side-chain polystyrenes with triphenylamine substituents on carbazole moieties were designed and characterized.

Mechanism of Synergistic Effect on Electron Transfer over Co-Ce/MCM-48 during Ozonation of Pharmaceuticals in Water.

The same amount of metal was deposited on the surface of three-dimensional mesoporous MCM-48 by a facile impregnation-calcination method for catalytic ozonation of pharmaceutical and personal-care products in the liquid phase. At 120 min reaction time, Co/MCM-48 and Ce/MCM-48 showed 46.6 and 63.

Planar tetracoordinate carbon species CLi3E with 12-valence-electrons.

We exhibit theoretically a series of 12-valence-electron pentaatomic species CLi3E (E = N, P, As, Sb, Bi) and CLi3E(+) (E = O, S, Se, Te, Po). The analyses of potential energy surfaces indicate that the C2v structures with a planar tetracoordinate carbon are the global minimum in these species except for E = N, P. A localized C[double bond, length as m-dash]E double bond is found in the planar tetracoordinate carbon species.

Spectroscopic analysis and in vitro imaging applications of a pH responsive AIE sensor with a two-input inhibit function.

A novel terpyridine derivative formed stable aggregates in aqueous media (DMSO/H2O = 1/99) with dramatically enhanced fluorescence compared to its organic solution. Moreover, the ultra-violet absorption spectra also demonstrated specific responses to the incorporation of water. The yellow emission at 557 nm changed to a solution with intense greenish luminescence only in the presence of protons and it conformed to a molecular logic gate with a two-input INHIBIT function.

Fabrication of SnO₂-reduced graphite oxide monolayer-ordered porous film gas sensor with tunable sensitivity through ultra-violet light irradiation.

A new graphene-based composite structure, monolayer-ordered macroporous film composed of a layer of orderly arranged macropores, was reported. As an example, SnO2-reduced graphite oxide monolayer-ordered macroporous film was fabricated on a ceramic tube substrate under the irradiation of ultra-violet light (UV), by taking the latex microsphere two-dimensional colloid crystal as a template. Graphite oxide sheets dispersed in SnSO4 aqueous solution exhibited excellent affinity with template microspheres and were in situ incorporated into the pore walls during UV-induced growth of SnO2.

Electric field effects on the intermolecular interactions in water whiskers: insight from structures, energetics, and properties.

Modulation of intermolecular interactions in response to external electric fields could be fundamental to the formation of unusual forms of water, such as water whiskers. However, a detailed understanding of the nature of intermolecular interactions in such systems is lacking. In this paper, we present novel theoretical results based on electron correlation calculations regarding the nature of H-bonds in water whiskers, which is revealed by studying their evolution under external electric fields with various field strengths.

Photochemistry-based method for the fabrication of SnO(2) monolayer ordered porous films with size-tunable surface pores for direct application in resistive-type gas sensor.

A new photochemistry-based method was introduced for fabricating SnO2 monolayer ordered porous films with size-tunable surface pores on ceramic tubes used for gas sensors. The growth of the spherical pore walls was controlled by two times irradiation of the ultraviolet light using polystyrene microsphere two-dimensional colloidal crystal as a template. The surface pore size of the final obtained porous films was well tuned by changing the second irradiation time rather than replacing the template microspheres.

Platinum(II)-catalyzed asymmetric ring-opening addition of arylboronic acids to oxabenzonorbornadienes.

A new platinum(II)-catalyzed asymmetric ring-opening addition of arylboronic acids to oxabenzonorbornadienes was developed, which afforded the corresponding cis-2-aryl-1,2-dihydronaphthalen-1-ol products in high yields (up to 97%) with moderate to good enantioselectivities (up to 89% ee) under very mild conditions. The effects of various ligands, catalyst loading, bases, solvents, and temperatures on the yield and enantioselectivity of the reaction were also investigated. The cis configuration of product 2m was confirmed by X-ray diffraction analysis.

Theoretical study on the reaction mechanisms of CH3O- with O2(X3Σ(g)-) and O2(a1Δ(g)).

The detailed potential energy surfaces (PESs) of poorly understood ion-molecule reactions of CH(3)O(-) with O(2)(X(3)Σ(g)(-)) and O(2)(a(1)Δ(g)) are accounted for by the density functional theory and ab initio of QCISD and CCSD(T) (single-point) theoretical levels with 6-311++G(d,p) and 6-311++G(3df,2pd) basis sets for the first time. For the reaction of CH(3)O(-) with O(2)(X(3)Σ(g)(-)) ((3)R), it is shown that a hydrogen-bonded complex (3)1 is initially formed on the triplet PES, which is 1.8 kcal/mol above reactants (3)R at the CCSD(T)//QCISD level, from which all the products P(1)-P(8) can be generated.

Gelification: an effective measure for achieving differently sized biocompatible Fe3O4 nanocrystals through a single preparation recipe.

Biocompatible Fe(3)O(4) nanocrystals were synthesized through the pyrolysis of ferric acetylacetonate (Fe(acac)(3)) in diphenyl oxide, in the presence of α,ω-dicarboxyl-terminated polyethylene glycol (HOOC-PEG-COOH) and oleylamine. Unusual gelification phenomena were observed from the aliquots extracted at different reaction stages after they were cooled to room temperature. By reaction time, the average size of the Fe(3)O(4) nanocrystals was tuned from 5.

Degradation of decabromodiphenyl ether by nano zero-valent iron immobilized in mesoporous silica microspheres.

The agglomeration of nanoparticles reduces the surface area and reactivity of nano zero-valent iron (NZVI). In this paper, highly dispersive and reactive NZVI immobilized in mesoporous silica microspheres covered with FeOOH was synthesized to form reactive mesoporous silica microspheres (SiO(2)@FeOOH@Fe). The characteristics of SiO(2)@FeOOH@Fe were analyzed by transmission electron microscopy, Fourier transform infrared spectroscopy simultaneous thermal analysis, X-ray photoelectron spectroscopy, and Brunnaer-Emmett-Teller surface area analysis.

Novel molecularly imprinted microsphere using a single chiral monomer and chirality-matching (S)-ketoprofen template.

We designed and synthesized a cinchonine derivative to be used as a novel chiral monomer. It was employed in a dual role of functional monomer and cross-linking monomer, displaying multi-binding sites for the template (S)-ketoprofen. Monodisperse molecularly imprinted core-shell microspheres were prepared using surface imprinting method on silica gel.

Enantioselective intramolecular crossed Rauhut-Currier reactions through cooperative nucleophilic activation and hydrogen-bonding catalysis: scope and mechanistic insight.

A highly efficient and enantioselective intramolecular crossed Rauhut-Currier (RC) reaction of nitroolefins with tethered enonates has been developed through cooperative nucleophilic activation and a hydrogen-bonding catalytic strategy (≤98% ee and 98% yield). The reaction features simple experimental procedures and is completely chemoselective and atom-economic in character. The potential synthetic applications have been demonstrated by the conversion of the RC reaction products into biologically and pharmaceutically valuable compounds with highly diastereoselectivity.

Theoretic calculation for understanding the oxidation process of 1,4-dimethoxybenzene-based compounds as redox shuttles for overcharge protection of lithium ion batteries.

The effect of substituents on the oxidation potential for the one-electron reaction of 1,4-dimethoxybenzene was understood with a theoretical calculation based on density functional theory (DFT) at the level of B3LYP/6-311+G(d). It is found that the oxidation potential for the one-electron reaction of 1,4-dimethoxybenzene is 4.13 V (vs Li/Li(+)) and can be changed from 3.

Theoretical investigations on oxidative stability of solvents and oxidative decomposition mechanism of ethylene carbonate for lithium ion battery use.

The electrochemical oxidative stability of solvent molecules used for lithium ion battery, ethylene carbonate (EC), propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate in the forms of simple molecule and coordination with anion PF(6)(-), is compared by using density functional theory at the level of B3LYP/6-311++G (d, p) in gas phase. EC is found to be the most stable against oxidation in its simple molecule. However, due to its highest dielectric constant among all the solvent molecules, EC coordinates with PF(6)(-) most strongly and reaches cathode most easily, resulting in its preferential oxidation on cathode.

Excess electron is trapped in a large single molecular cage C60F60.

A new kind of solvated electron systems, sphere-shaped e(-)@C60F60 (I(h)) and capsule-shaped e(-)@C60F60 (D6h), in contrast to the endohedral complex M@C60, is represented at the B3LYP/6-31G(d) + dBF (diffusive basis functions) density functional theory. It is proven, by examining the singly occupied molecular orbital (SOMO) and the spin density map of e(-)@C60F60, that the excess electron is indeed encapsulated inside the C60F60 cage. The shape of the electron cloud in SOMO matches with the shape of C60F60 cage.

Bimetallic clusters Pt6Au: geometric and electronic structures within density functional theory.

Within density functional theory at the general gradient approximation for exchange and correlation (BPW91) and the relativistic 19-electron Los Alamos National Laboratory effective core pseudopotentials and basis sets (3s3p2d), the geometric and electronic structures of Pt(6)Au bimetallic clusters have been studied in detail in comparison with Pt(7). A total of 38 conformations for Pt(6)Au are located. The most stable conformation for Pt(6)Au is a sextet with an edge- and face-capped trigonal bipyramid, in which the Au atom caps an edge of the trigonal bipyramid.