Dynamic Reaction Mechanisms of ClO¯ with CH₃Cl: Comparison Between Direct Dynamics Trajectory Simulations and Experiment

We have investigated the dynamic reaction mechanisms of *ClO¯ with CH3Cl (the asterisk is utilized to label a different Cl atom). Ab initio molecular dynamics simulations at the MP2/6-31+G­(d,p) level of theory have been employed to compute the dynamic trajectories. On the basis of our simulations, the dynamic reaction pathways for the bimolecular nucleophilic substitution (SN2) reaction channel and SN2-induced elimination reaction channel are clearly illustrated. For the SN2 reaction channel, some trajectories directly dissociate to the final products of CH3O*Cl and Cl¯, whereas the others involve the dynamic Cl¯···CH3O*Cl intermediate complex. As to the SN2-induced elimination reaction channel, the trajectories lead to the final products of CH2O, HCl, and *Cl¯ through the dynamic Cl¯···CH3O*Cl intermediate complex. More significantly, the product branching ratios of Cl¯ and *Cl¯ predicted by our simulations are basically consistent with previous experimental results (Villano et al. J. Am. Chem. Soc. 2009, 131, 8227–8233)

Origin of the Microsolvation Effect on the Central Barriers of S_N2 Reactions

We have quantitatively analyzed the microsolvation effect on the central barriers of microsolvated bimolecular nucleophilic substitution (SN2) reactions by means of a two-step energy decomposition procedure. According to the first energy decompositions, an obvious increase in the central barrier for a microsolvated SN2 reaction against its unsolvated counterpart can be mainly ascribed to the fact that the interaction between the solute and the conjunct solvent becomes less attractive from the reactant complex to the transition state. On the basis of the second energy decompositions with symmetry-adapted perturbation theory, this less attractive interaction in the transition state is primarily due to the interplay of the changes in the electrostatic, exchange, and induction components. However, the contribution of the change for the dispersion component is relatively small. A distinct linear correlation has also been observed between the changes of the total interaction energies and those of the corresponding electrostatic components for the microsolvated SN2 reactions studied in this work. Moreover, the two-step energy decomposition procedure employed in this work is expected to be extensively applied to the gas phase reactions mediated by molecules or clusters

Spin-Component-Scaled Double-Hybrid Density Functionals with Nonlocal van der Waals Correlations for Noncovalent Interactions

Nonlocal (NL) van der Waals correlation has been incorporated into the spin-component and spin-opposite scaled double-hybrid density functionals (DHDFs) for noncovalent interactions. The short-range attenuation parameters for the tested DHDFs with the NL correlations are optimized by minimizing the mean absolute deviations (MADs) against the S66 database. And consequently, the obtained DHDFs with the NL correlations are denoted as PWPB95-NL, DSD-BLYP-NL, DSD-PBEP86-NL, and DOD-PBEP86-NL. These four DHDFs with the NL correlations are further assessed with the S22B, NCCE31, and ADIM6 databases. On the basis of our benchmark computations, the cooperation of the NL correlation and the spin-component and spin-opposite scaled DHDFs is successful for noncovalent interactions. However, the performances of the four aforementioned DHDFs with the NL correlations on the charge transfer interactions are less than satisfactory

Double-Hybrid Density Functionals Free of Dispersion and Counterpoise Corrections for Non-Covalent Interactions

We have optimized two double-hybrid density functionals (DHDFs) within the frameworks of B2PLYP and mPW2-PLYP against the S22B database. These two functionals are denoted as B2NC-PLYP and mPW2NC-PLYP, where “NC” represents noncovalent interaction. The DHDFs of B2NC-PLYP and mPW2NC-PLYP are optimized free of dispersion and counterpoise corrections with triple-ζ quality basis sets. Combined with the aug-cc-pVTZ basis set, these two functionals are further assessed with the S66 database. According to our computations, both the B2NC-PLYP and mPW2NC-PLYP functionals seem to be competent for investigating noncovalent interactions. Note that the triple-ζ quality basis sets with adequate polarization and diffuse functions should be employed for practical applications. However, different exchange and correlation functionals may be selected and/or modified to reduce the amount of the Fock-exchange in the future

Efficient Production of Valuable Aromatic <i>N</i>‑Heterocycles from Bio-Polyols by Heterogeneous Catalysis via Controlling Unstable Intermediate Conversion

Efficient and controllable conversion of renewable polyols to valuable N-containing products by heterogeneous catalysis, especially under relativley mild conditions (<200 °C), remains a significant challenge. Here, we develop a method for one-step efficient production of 2-methylquinoxalines (2-MQs), a type of high-value aromatic N-heterocycles, directly from polyols in the presence of supported Pt dehydrogenation catalyst through controllably in situ trapping reactive pyruvaldehyde (PA) intermediate by aryl-1,2-diamine at the temperature of only 140 °C. The presence of aryl-1,2-diamine not only enabled the formation of 2-MQs, but also markedly enhanced the polyols’ carbon utilization to near-quantitative (>98 C%) level. More importantly, organic solvent-enabled kinetics control of competitive reactions associated with PA transformation, i.e., the condensation with aryl-1,2-diamine to produce 2-MQs and the Cannizzaro reaction to form lactic acid, allowed to access the desired 2-MQs in a controllable manner with yields ranging from 12 C% to 81 C%. The application of this approach to attain diverse 2-MQs and analogues of interest in pharmaceutical industry has been demonstrated

Noncovalent Interactions in Hydrated Nitrosonium Ion Clusters Mediated by Hydrogen-Bonded Water Networks

As important species in the D region of the ionosphere, hydrated nitrosonium ion clusters [NO+(H2O)n] are also archetypal and concise models to illustrate effects of different solvent shells. We have investigated noncovalent interactions in NO+(H2O)3 and NO+(H2O)4 isomers with high levels of ab initio and symmetry-adapted perturbation theory (SAPT) methods. On the basis of our computations, the exchange energies become much more repulsive, whereas the induction energies are significantly more attractive for the noncovalent interactions of NO+ with hydrogen-bonded water chains. Combined with analyses of the electron densities for the NO+(H2O)3 and NO+(H2O)4 isomers, we propose that the counteracting effect of the exchange and induction energies could be deemed as an index for the tendency to form the HO–NO covalent bond. Moreover, we have also found that the third-order induction terms are very important to evaluate reasonable charge transfer energies with the SAPT computations

Structural Preferences Shape the Entropic Force of Disordered Protein Ensembles

Intrinsically disordered protein regions (IDRs) make up over 30% of the human proteome and exist in a dynamic conformational ensemble instead of a native, well-folded structure. Tethering IDRs to a surface (for example, the surface of a well-folded region of the same protein) can reduce the number of accessible conformations in these ensembles. This reduces the ensemble’s conformational entropy, generating an effective entropic force that pulls away from the point of tethering. Recent experimental work has shown that this entropic force causes measurable, physiologically relevant changes to protein function. But how the magnitude of this force depends on IDR sequence remains unexplored. Here, we use all-atom simulations to analyze how structural preferences in IDR ensembles contribute to the entropic force they exert upon tethering. We show that sequence-encoded structural preferences play an important role in determining the magnitude of this force: compact, spherical ensembles generate an entropic force that can be several times higher than more extended ensembles. We further show that changes in the surrounding solution’s chemistry can modulate the IDR entropic force strength. We propose that the entropic force is a sequence-dependent, environmentally tunable property of terminal IDR sequences

Structural Preferences Shape the Entropic Force of Disordered Protein Ensembles

Intrinsically disordered protein regions (IDRs) make up over 30% of the human proteome and exist in a dynamic conformational ensemble instead of a native, well-folded structure. Tethering IDRs to a surface (for example, the surface of a well-folded region of the same protein) can reduce the number of accessible conformations in these ensembles. This reduces the ensemble’s conformational entropy, generating an effective entropic force that pulls away from the point of tethering. Recent experimental work has shown that this entropic force causes measurable, physiologically relevant changes to protein function. But how the magnitude of this force depends on IDR sequence remains unexplored. Here, we use all-atom simulations to analyze how structural preferences in IDR ensembles contribute to the entropic force they exert upon tethering. We show that sequence-encoded structural preferences play an important role in determining the magnitude of this force: compact, spherical ensembles generate an entropic force that can be several times higher than more extended ensembles. We further show that changes in the surrounding solution’s chemistry can modulate the IDR entropic force strength. We propose that the entropic force is a sequence-dependent, environmentally tunable property of terminal IDR sequences

Data_Sheet_1_Nexus Between Consumer’s Motivations and Online Purchase Intentions of Fashion Products: A Perspective of Social Media Marketing.docx

This study aimed to investigate the effects of customers’ motivations (specifically young consumers) on online purchase intentions as mediated by commitment toward online fashion retailers. The survey method was used to collect data from Chinese respondents using a questionnaire. The convenience sampling technique was used to collect data from 275 respondents. Collected data were analyzed on smart-PLS using the structural equation modeling technique. Results of the study show a significant and positive impact of social empowerment and remuneration motivations on consumer commitment online purchase intention. Further results show that consumer commitment partially mediates the relationship between social empowerment, remuneration, and online purchase intention. This study contributes to the literature in the domain of consumer commitment by focusing on the underlying needs and motivations of consumers. The researchers have demonstrated a strong need to understand the dynamics of commitment due to its importance in affecting purchase intention. This study also has several implications that guide online retailers how to motivate consumers with social, remuneration and empowerment incentives to develop their intention to purchase online. Fashion retailers are suggested to gratify certain consumer motives to increase commitment. Specifically, among the three motives, empowerment motivation emerged as the strongest predictor of consumer commitment in social media environment. This study will help to the online brands to attract more customers by providing the motivation such financial, empowerment and socialization.</p

326 differently abundant proteins

The dataset included urinary proteins that were differently abundant between adult donkeys and donkey foals. </div