Solvent Effects on Isomerization and Spectral Properties of Photochromic-Switching Diarythene Derivatives in Polar and Apolar Solutions

The photocyclization behavior and dynamic conformational transition of photochromic switches of diarythene derivatives in solutions are investigated by using the density functional theory (DFT) and molecular dynamics (MD) simulations. Three possible conformations, antiparallel (anti), parallel (para), and twist, for the open-ring isomers of 1,2-bis(2-methylbenzothiophene-3-yl)maleic anhydride are located. Both PCM-B3LYP/6-31G* calculations and MD simulations demonstrate that anti and twist open-ring isomers can interconvert freely in <i>n</i>-hexane and acetonitrile solutions at room temperature. The statistical ratio of twist to anti isomers from MD simulations is 2.09 in <i>n</i>-hexane and 1.07 in CH₃CN, in qualitative agreement with those (1.18 in <i>n</i>-hexane and 1.05 in CH₃CN) estimated from Arrhenius analysis of DFT activation energies. The solvent polarity has little influence on the isomerization of open-ring isomers in the ground state. Due to the evident charge transfer upon excitations, the solvent effects on the electronic structures and absorption spectra of low-lying excited states (S₁ and S₂) are more significant. For such charge-transfer excited states, the long-range corrected functional CAM-B3LYP gives better agreement with the experimental spectra than B3LYP. The solvent polarity and polarization of the charge-transfer excited states are crucial for fabricating the novel functionalized photochromic molecular switches

Modulating Morphology of Thiol-Based Monolayers in Honeycomb Hydrogen-Bonded Nanoporous Templates on the Au(111) Surface: Simulations with the Modified Force Field

The difference in monolayer morphology caused by different functional thiols (ASH, BP3SH, and C12SH) within the surface-supported porous network of naphthalene tetracarboxylic di-imide (NDI) and melamine (MEL) molecules has been investigated by molecular dynamics simulations with the modified force field. The hydrogen-bonded bimolecular network is taken as the template when different thiols are deposited on the Au(111) surface. Force field parameters of intermolecular (NDI–NDI, MEL–MEL, NDI–MEL, and thiol–thiol) and interfacial (Au···S) interactions are modified to reproduce MP2 potential energy curves and the adsorption height. Interfacial interactions between the network and the Au(111) surface support the NDI–MEL bimolecular template, lying flat in an ordered hexagonal pattern on the substrate. The packing morphology of the triple hydrogen-bonded network obtained from molecular dynamics simulations and quantum chemical calculations matches the image from the scanning tunneling microscope. The backbone flexibility, which varies with the length and shape of thiol chains, is demonstrated to affect the monolayer morphology. The packing arrangement tends to be more ordered with the increase of the coverage for alkane thiols. The subsequently deposited thiols also disturb the bicomponent nanopore to a different extent, originating from the subtle balance between the thiol–thiol, thiol–template, and the intratemplate hydrogen-bonding interactions. It is demonstrated that the aromatic rings in BP3SH add a chance to perturb the host network through the π···π stacking in low coverage. The understanding of nanotemplate effect on the thiol-based monolayer growth is helpful for fabricating novel surface-supported host–guest hybrid nanodevices at the single molecular level

Theoretical Designs of Photoresponsive Energy-Storage Materials Based on Attachment of π‑Conjugated Molecules onto Sulfur-Doped Graphene

Introducing heteroatom active sites and functional units is essential for achieving high-performance graphene in potential applications of optoelectronic devices and sustainable solar-heat energy conversion/storage. Density functional theory calculations with long-range van der Waals effects (vdW-DF2) were performed to study the electronic structures and energy storage/release of graphene through sulfur (S)-doping and physisorption of π-conjugated photoresponsive molecules, <i>trans</i>/<i>cis</i>-azobenzene (AB) derivatives with an electron-donating substituent group and <i>trans</i>/<i>cis</i>-stilbene (ST), respectively. With the increase of the S-doping concentration from 0.4 to 0.8 atom/nm², the band gap of graphene exhibits the enhanced metallic characteristics with a direct-to-indirect transition. Although AB and ST molecules have different unsaturated bridge bonds, −NN– versus −CHCH–, physisorption of these two photoresponsive molecules onto the graphene can both broaden the band gap to about 0.02 eV, as a result of the π–π interfacial interactions. Under the exposure to the solar light, the facile <i>trans</i>-to-<i>cis</i> isomerization of the AB (ST) molecule adsorbed onto graphene renders the energy storage of about 1.04 eV (0.49 eV) in each molecule. The noncovalent physisorption of <i>trans</i>/<i>cis</i>-AB molecules onto graphene is unexpectedly more favorable to energy storage than that of covalent binding. In addition, a multifunctional graphene model, with the combination of both S-doping and physisorption of photoresponsive moelcules, could not only open a band gap of about 0.27 eV but also induce energy storage of 0.84 eV per molecule via the conformational change from <i>trans</i>- to <i>cis</i>-AB isomer. Strong charge localization at the S dopant may become the active sites for catalysis and energy storage, and meanwhile, photoactive adsorbates could further promote the energy conservation and release

Dual Role of a Photocatalyst: Generation of Ni(0) Catalyst and Promotion of Catalytic C–N Bond Formation

Photoredox/transition-metal dual catalysis has become a hot research topic in the development of methodologies. Density functional theory (DFT) calculations have been performed to explore the detailed mechanism of photoredox/Ni-catalyzed carbon–nitrogen cross-coupling. The Ni(0) catalyst initiates the C–N cross-coupling, and the photocatalyst *­[Ir­(III)]⁺ engages the Ni­(II) complex in single-electron transfer (SET). The pathway of the Ni­(I) catalyst initiating the catalytic cycle is prohibited due to the relatively high activation barrier of the oxidative addition of the aryl bromide to the Ni­(I) catalyst. It is predicted that the Ni­(II) salt is reduced by pyrrolidine through the mechanism of photoredox-catalyzed hydrogen atom transfer (HAT). The triplet–triplet energy transfer (TTET) between the photocatalyst and the Ni­(II) complex is less likely to occur due to the mismatched energy levels

Supplemental Material - The effects of prone position ventilation on patients with acute respiratory distress syndrome after cardiac surgery

Supplemental Material for The effects of prone position ventilation on patients with acute respiratory distress syndrome after cardiac surgery by Yujie Zhang, Wangtao Zhou, and Jing Ma in Perfusion.</p

The impact of export VAT rebates on firm productivity: Evidence from China

This paper studies the impact of export VAT rebates on firm productivity with Chinese firm-product-level data. We find that higher VAT rebates significantly raise firm productivity. The results are robust to various estimations of firm productivity. Moreover, this paper finds that the impact of export VAT rebates on firm productivity is significantly different across firms and sectors. More specifically, our results suggest that the impact is mainly driven by firms with small export intensive margins and large export extensive margins, new exporters, financially constrained firms and low-productivity firms. Furthermore, in high-tech sectors, the impact is significantly large with a one percentage point increase of the firm rate of VAT rebates nearly raising firm productivity by 6%.<br

Supplementary Information Files for The employment and wage effects of export VAT rebates: evidence from China

Supplementary Information Files for The employment and wage effects of export VAT rebates: evidence from ChinaThis paper studies the employment and wage effects of VAT rebates to exporters with comprehensive firm-product-level data of China. It is found that the adjustments in VAT rebates significantly and positively affect firm’s employment but have no statistically significant effect on firm’s wage. Moreover, this paper finds that the employment effect of VAT rebates is heterogeneous across firms. In particular, low-productivity firms are more sensitive to the adjustments of VAT rebates than high-productivity firms, suggesting that an increase of VAT rebates may cause mis-reallocation of resources.<br

Data_Sheet_1_What is effective classroom dialog? A comparative study of classroom dialog in Chinese expert and novice mathematics teachers’ classrooms.docx

Conducting effective classroom dialog is an important foundation for high-quality classrooms. This study investigates the characteristics of effective classroom dialog from the perspective of Chinese mathematics classrooms. Classroom videotapes from 40 expert and 33 novice teachers were selected from a national project and analyzed through a developed coding framework. Results showed that the dominant types of dialog in expert teachers’ classrooms were related to Basic Knowledge, Construction, Analysis, and Personal Information. Compared to novice teachers, expert teachers’ classrooms have a significantly lower proportion of dialog on Basic Knowledge and significantly higher proportions of dialog on Personal Information and Speculation. Based on expert teachers’ classrooms, the characteristics of effective classroom dialog in the Chinese context were discussed. The analytical framework for classroom dialog developed in this study could be a powerful tool for subsequent research. Suggestions are provided on increasing the effectiveness of classroom dialog.</p

Setting local economic growth targets: does it mitigate nationwide policy uncertainty?

Institutional theory holds that local governance is essential in shaping regional economic activity. This study evaluates whether local economic growth targets offset the detrimental effect of nationwide policy uncertainty on local business performance. Regression analyses of data from industrial firms and manually collected data on city economic growth targets in China show that higher local growth targets result in greater corporate investment, conditional on nationwide policy uncertainty, and that the impact is substantial through financial subsidies and allocating credit resources. However, local discretion in economic growth target setting might cause investment misallocation and efficiency loss.</p

sj-docx-1-jht-10.1177_10963480241229236 – Supplemental material for Do Happier People Like Traveling More?

Supplemental material, sj-docx-1-jht-10.1177_10963480241229236 for Do Happier People Like Traveling More? by Jing Ma, Xinjing Wang and Lihui Tian in Journal of Hospitality & Tourism Research</p