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Low room temperature ionic conductivity and interfacial incompatibility are the key factors that hinder the practical application of solid polymer electrolyte (SPEs) in lithium metal batteries. Increasing the ability of the SPEs to dissolve and dissociate lithium salt is helpful to enhance ion transport capacity of the SPEs. Herein, ketone groups with high solubility and dissociation ability of lithium salt are introduced into the structural design of SPE, an aliphatic ketone solid polymer electrolyte (KT@SPE) with crosslinking structure is prepared by ultraviolet (UV) polymerization. The prepared KT@SPE shows excellent viscoelastic and possess room temperature ionic conductivity of 10−4 S cm−1 with 200 wt% lithium bis((trifluoromethyl)sulfonyl)azanide (LiTFSI). Thanks to the contribution of high ion transport capacity, construction of multi‐hydrogen bonds network structure of KT@SPE and a wettability of controlling residual dimethyl sulfoxide (DMSO) solvent to the interface, the assembled symmetrical Li cell realizes stable cycling for over 2000 h at 0.15 mA cm−2. Moreover, LiFePO4 cell achieves stable long cycle at 5C and enable Li/KT@SPE3/LiFe0.6Mn0.4PO4 cell operates at 4.4 V. This work not only provides a design strategy for preparing novel solid polymer electrolytes, but also exhibits the excellent application potential of aliphatic ketone‐based polymer electrolyte in solid‐state lithium batteries at high current density and high voltage. [ABSTRACT FROM AUTHOR]

Polymer‐based solid electrolyte boasting ultra‐high safety, energy density, mechanical strength and flexibility, attracting much attention in the field of battery applications. However, its widespread application is hindered by the low conductivity, insufficient aluminium salt dissociation, high crystallization degree, short service life, etc. To solve the above problems, a composite solid polymer electrolyte (SPE) design based on polyethylene oxide (PEO, Mw = 6 000 000) with AlCl3·6H2O as aluminum salt and butanedinitrile (SN) as plasticizer is proposed in this paper. The disorder and mobility of the PEO chains, conductivity, degree of aluminum salt dissociation, and service life are enhanced by the addition of plasticizer SN. Theoretical calculation demonstrates the formation of solvated sheath‐like structure [SN…Al3+] has strong interactions with the polymer PEO, allowing rapid transport of Al3+ through the polymer segments. These results are also further verified by subsequent tests, which can reveal the Al3+ transport mechanism of room‐temperature SPEs in a more reasonable way. Meanwhile, the relatively strong binding energy between PEO and SN can help to avoid the parasitic reaction between SN and Al, increase the service life of solid‐state aluminium‐ion batteries. Providing a promising solution for the design of solid‐state battery electrolytes that can be applied at room temperature. [ABSTRACT FROM AUTHOR]

Exploring the microscopic reaction mechanism of dicyandiamide (DCD) synthesis using calcium cyanamide (CaCN2) is highly desirable because of the low conversion of reactants and selectivity of DCD products. DCD synthesis consists of a two-step sequential hydrolysis of CaCN2, followed by dimerization of cyanamide to DCD in an alkaline environment. Density functional theory (DFT) results revealed that the rate-limiting step (RLS) was the formation of a C-N bond between the cyanamide and cyanamide anion in the dimerization of the DCD reaction. Secondary reactions of cyanamide with water, hydrogen sulfide, and DCD were also analyzed. The effects of solvation on the principal and secondary reactions were systematically explored. A single explicit water molecule can significantly lower the free energy barrier of the RLS. Water molecules facilitate the C-N bonding of the reactants in DCD reactions, resulting in a reduction in the free energy barrier of the RLS. The facilitation of double explicit water for the reaction is weaker than that of single explicit water and even yields negative catalysis. The effect of the [OH(H2O)3]− cluster lowering the reaction barrier with the hydrogen-bonding network is the most remarkable, which can alter the reaction path by the direct and indirect involvement of OH− ions. Furthermore, the reaction rate constants were computed by canonical variational theory with the Eckart tunneling correction (CVT/Eckart) and fitted to the Arrhenius expression. The reaction mechanism and kinetics revealed at the microscopic level provide efficient and clean production of DCD with certain theoretical guidance. [ABSTRACT FROM AUTHOR]

Density functional theory‐based molecular dynamics (DFT‐MD) combined with an explicit solvation model were employed to further elucidate the O─O bond formation step in Fe─TAML catalyzed water oxidation reaction. The water nucleophilic attack (WNA) and nitrate nucleophilic attack (NNA) on the oxo group of the high‐valent [TAML+•─Fe5+═O] species were calculated to have comparable active barriers (24 kcal/mol versus 22 kcal/mol). This suggests nitrate ion can behave as a cocatalyst to promote the O─O bond formation. More importantly, a crucial role of the presence and thermal motion of solvent water in the NNA process was observed. This was quantified by an increase of the activation energy barrier by 4 kcal/mol, determined by comparing the explicit solvent DFT‐MD simulation with implicit solvent static DFT calculation. [ABSTRACT FROM AUTHOR]

Density Functional Theory (DFT) and Molecular docking are pivotal computational techniques in modern chemistry and drug design. This work investigates the electronic structure and reactivity of 2-thiophenecarbonitrile (2TCN) with an emphasis on important factors such as HOMO-LUMO energy gap, MEP, Mulliken atomic charges, natural population analysis, and Mutiwfn (ELF, LOL, ALIE, and RDG) analysis. The MEP and FMO studies were calculated in various solvents like acetonitrile, water, gas, and methanol. The anti-inflammatory and antioxidant investigations revealed substantial activities by 2TCN. Additionally, molecular docking studies are performed to elucidate the binding interaction between the compound and target proteins, providing insights into its potential therapeutic mechanisms. The results demonstrate the binding energies, interaction residues, and the most favorable docking poses. This approach underscores the integration of theoretical and computational methods in advancing molecule design and therapeutic discovery.

Current potassium‐ion batteries (PIBs) are limited in safety and lifetime owing to the lack of suitable electrolyte solutions. To address these issues, herein, we report an innovative non‐flammable electrolyte design strategy that leverages an optimal moderate solvation phosphate‐based solvent which strikes a balance between solvation capability and salt dissociation ability, leading to superior electrochemical performance. The formulated electrolyte simultaneously exhibits the advantages of low salt concentration (only 0.6 M), low viscosity, high ionic conductivity, high oxidative stability, and safety. Our electrolyte also promotes the formation of self‐limiting inorganic‐rich interphases at the anode surface, alongside robust cathode‐electrolyte interphase on iron‐based Prussian blue analogues, mitigating electrode/electrolyte side reactions and preventing Fe dissolution. Notably, the PIBs employing our electrolyte exhibit exceptional durability, with 80 % capacity retention after 2,000 cycles at high‐voltage of 4.2 V in a coin cell. Impressively, in a larger scale pouch cell, it maintains over 81 % of its initial capacity after 1,400 cycles at 1 C‐rate with high average Coulombic efficiency of 99.6 %. This work represents a significant advancement toward the realization of safe, sustainable, and high‐performance PIBs. [ABSTRACT FROM AUTHOR]

Hydroxy‐2‐(4‐(pyrrolidin‐1‐yl)phenyl)benzo[g]quinolin‐4(1H)‐one (PBQ) is a ratiometric fluorescent probe based on excited‐state intramolecular proton transfer (ESIPT). PBQ‐1 is the reaction product following its exposure to phosgene. Density functional theory (DFT) and time dependent density functional theory (DFT) have been used to study the excited state dynamics of PBQ and PBQ‐1 in different solvents. The results show that the reaction of PBQ with a transition from charge‐transfer excitation to local excitation before and after the reaction. It becomes more difficult for PBQ in the excited state to transfer proton with increasing solvent polarity. The product PBQ‐1 undergoes a molecular structure twist, and the angle of twisting decreases with increasing solvent polarity, resulting in a lower degree of rotational freedom of the hydroxyl group (5‐OH) at the 5th carbon position, which makes it more susceptible to ESIPT reactions. Therefore, PBQ‐1 is more susceptible to ESIPT as solvent polarity increases. Our theoretical calculations also elucidate the cause of the blue shift of PBQ fluorescence and the impact of the twisting intramolecular charge transfer phenomenon on the solvent effect. Furthermore, our study provides the theoretical guidance for the designing probe based on excited state intramolecular proton transfer. [ABSTRACT FROM AUTHOR]

Copper (Cu) is an important transition metal, and its isotopes have important applications in geology, environmental science, soil science, and other fields. Cu isotope fractionation can occur in many natural processes. However, the mechanism of Cu isotope fractionation in solution/hydrothermal solution systems is not very clear. In this study, the fractionation effects of complexes of Cu(I) and Cu(II) in solution/hydrothermal solution systems were systematically studied by means of an ab initio method based on first principles. In the simulation of an aqueous solution system, the theoretical treatment method used is the "water-droplet" method. The results show that the heavy Cu isotope (65Cu) enrichment capacity of the Cu-bearing complex solutions is greatly affected by the ligand types both for Cu(I) and Cu(II). For Cu(I) complex solutions, the heavy Cu isotope enrichment sequence is [Cu(HS)2]−·(H2O)42 > [Cu(HS)(H2O)]·(H2O)42 ≈ [Cu(HS)(H2S)]·(H2O)42 > [CuCl]·(H2O)42 > [CuCl2]−·(H2O)42 > [CuCl3]2−·(H2O)42. For the aqueous solutions of Cu(II) with an inorganic ligand (such as H2O, OH−, NO3−, SO42− and CN−), the order of heavy Cu isotope enrichment is as follows: [Cu(H2O)6]2+·(H2O)42 > [Cu(NO3)2]·(H2O)42 > [Cu(OH)2]·(H2O)42 > [CuSO4(H2O)3]·(H2O)42 > [CuNO3(H2O)4]+·(H2O)42 > [CuCN]+·(H2O)42. For the Cu(II) complex solutions with a halogen as ligands, the change order of 1000lnβ is [CuCl]+·(H2O)42 > [CuCl2]·(H2O)42 > [CuBr2]·(H2O)42 > [CuCl3]−·(H2O)42. The sequence of 1000lnβ for Cu(II) organic complex aqueous solutions is [Cu(HOC6H4COO)]+·(H2O)42 > [Cu(CH3CH2COO)]+·(H2O)42 > [Cu(COOHCOO)]+·(H2O)42. The calculation also found that for Cu(I) complex aqueous solutions, the difference in Cu isotope fractionation parameters (1000lnβ) between [CuCl2]−·(H2O)42 and [Cu(HS)2]−·(H2O)42 is relatively large. At 100 °C, the 1000lnβ of the two species are 1.14 and 1.55 (‰), respectively. The difference between the two could be reached up to 0.41 (‰). The Cu isotope fractionation parameter obtained with the "water droplet" method is also very different from the results of previous studies, which indicate that the Cu isotope fractionation behavior of the two is similar. At the same time, the exciting discovery is that the enrichment capacity of heavy Cu isotopes is significantly different between Cu(I) complex aqueous solutions and Cu(II) complex aqueous solutions. At 100 °C, the 1000lnβ of 6 Cu(I) complex aqueous solutions and 13 Cu(II) complex aqueous solutions ranged from 0.90 to 1.55 and 2.24 to 3.25(‰), respectively. It also shows that the REDOX reaction has a significant effect on the Cu isotope fractionation, especially in ore-forming fluids. Therefore, the ligand type is a factor that cannot be ignored when considering the mechanism of Cu isotope fractionation in solution/hydrothermal solution systems. Whether the solvation effect of an aqueous solution is considered or not has a great influence on the numerical values of the final Cu isotope fractionation factors. Hence, the solvation effect of an aqueous solution is an essential determinant in the theoretical calculation of the Cu isotope fractionation factors for Cu-bearing complex solutions. [ABSTRACT FROM AUTHOR]

Conformational search and density functional theory calculations were performed to explore the preferences of helical structures for chiro‐specific oligo‐γ‐peptides of 2‐(aminomethyl)cyclopentanecarboxylic acid (γAmc5) with a cyclopentyl constraint on the Cα–Cβ bond in solution. The dimer and tetramer of γAmc5 (1) with homochiral (1S, 2S) configurations exhibited a strong preference for the 9‐membered helix foldamer in solution, except for the tetramer in water. However, the oligomers of γAmc5 (1) longer than tetramer preferentially adopted a right‐handed (P)‐2.614‐helix (H1‐14) as the peptide sequence becomes longer and as solvent polarity increases. The high stabilities for H1‐14 foldamers of γAmc5 (1) in solution were ascribed to the favored solvation free energies. The calculated mean backbone torsion angles for H1‐14 helix foldamers of γAmc5 (1) were similar to those calculated for oligomers of other γ‐residues with cyclopentane or cyclohexane rings. However, the substitution of cyclopentane constraints on the Cα−Cβ bond of the γAmc5 (1) residue resulted in different conformational preferences and/or handedness of helix foldamers. In particular, the pyrrolidine‐substituted analogs of the H1‐14 foldamers of γAmc5 (1) with adjacent amine diads substituted at a proximal distance are expected to be potential catalysts for the crossed aldol condensation in nonpolar and polar solvents. [ABSTRACT FROM AUTHOR]

In this study, 12 phenolic acids were theoretically calculated using the M06-2X functional. To explain their antioxidant and solvation effects, bond dissociation enthalpy (BDE), ionization potential (IP), proton dissociation enthalpy (PDE), proton affinity (PA) and electron transfer enthalpy (ETE) were calculated for each phenolic acid in the gas phase and solvents. The results showed that the BDE of gentianic acid (C5) in the gas phase was the lowest. In terms of BDE, caffeic acid (C6) had the strongest antioxidant effect in benzene, gentianic acid (C5) in acetone, and 3,4-dihydroxybenzyl alcohol (C2) in ethanol and water. In terms of IP, resveratrol had the best antioxidant activity in 4 solvents and in the gas phase. The antioxidant mechanism of phenolic acids was mainly related to hydrogen atom transfer (HAT). It was found that the ability of dehydrogenated anions and cations of phenolic acids to generate dehydrogenated free radicals was consistent with the influence of solvent polarity on IP, BDE, PDE, PA and ETE. In general, the antioxidant capacity of phenolic acids was the strongest in the weakly polar solvent acetone, followed by the strongly polar solvents water and ethanol, and phenolic acids had the weakest antioxidant capacity in non-polar solvents.

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Aqueous rechargeable multivalent metal‐ion batteries (ARMMBs) have attracted considerable attention due to their high capacity, high energy density, and low cost. However, their performance is often limited by low temperature operation, which requires the development of anti‐freezing electrolytes. In this review, we summarize the anti‐freezing mechanisms and optimization strategies of anti‐freezing electrolytes for aqueous batteries (especially for Zn‐ion batteries). Besides, we investigate the possible interactions and side reactions between electrolytes and electrodes. We also analyze the problems between electrolytes and electrodes at low temperature, and propose possible solutions. The research progress in the field of low temperature energy storage for aqueous Mg‐ion, Ca‐ion, and Al‐ion batteries, and the challenges faced in their anti‐freezing electrolytes are investigated in detail. Last but not least, the outlook on the energy storage applications of ARMMBs is provided to guide the future research. [ABSTRACT FROM AUTHOR]

Computational studies of pyrimidine derivatives' interaction with metal clusters (Ag/Au/Cu) in various solvents are presented. Cu cluster adsorption energies are highest, while Ag cluster adsorption energies are lowest. Because the change in enthalpy is negative, the adsorption processes are exothermic, which is advantageous for drug delivery applications. The electrophilicity index of all metal-drugs systems are higher than the drug's value of drug, indicating that the drugs have a tendency to become more electrophilic once metal clusters are added. The cluster's conductivity improved as the energy gaps decreases and the might be employed as a drug sensor. The solvation energies in solvents are greater negative indicating that the solvent medium is more stable. Evaluation of non-covalent interactions showed significant interactions between the molecules and clusters. Electron localization function (ELF) and average local ionization energy (ALIE) studies also confirm electron delocalization. [ABSTRACT FROM AUTHOR]

Copper (Cu) is an important transition metal, and its isotopes have important applications in geology, environmental science, soil science, and other fields. Cu isotope fractionation can occur in many natural processes. However, the mechanism of Cu isotope fractionation in solution/hydrothermal solution systems is not very clear. In this study, the fractionation effects of complexes of Cu(I) and Cu(II) in solution/hydrothermal solution systems were systematically studied by means of an ab initio method based on first principles. In the simulation of an aqueous solution system, the theoretical treatment method used is the “water-droplet” method. The results show that the heavy Cu isotope (65Cu) enrichment capacity of the Cu-bearing complex solutions is greatly affected by the ligand types both for Cu(I) and Cu(II). For Cu(I) complex solutions, the heavy Cu isotope enrichment sequence is [Cu(HS)2]−·(H2O)42 > [Cu(HS)(H2O)]·(H2O)42 ≈ [Cu(HS)(H2S)]·(H2O)42 > [CuCl]·(H2O)42 > [CuCl2]−·(H2O)42 > [CuCl3]2−·(H2O)42. For the aqueous solutions of Cu(II) with an inorganic ligand (such as H2O, OH−, NO3−, SO42− and CN−), the order of heavy Cu isotope enrichment is as follows: [Cu(H2O)6]2+·(H2O)42 > [Cu(NO3)2]·(H2O)42 > [Cu(OH)2]·(H2O)42 > [CuSO4(H2O)3]·(H2O)42 > [CuNO3(H2O)4]+·(H2O)42 > [CuCN]+·(H2O)42. For the Cu(II) complex solutions with a halogen as ligands, the change order of 1000lnβ is [CuCl]+·(H2O)42 > [CuCl2]·(H2O)42 > [CuBr2]·(H2O)42 > [CuCl3]−·(H2O)42. The sequence of 1000lnβ for Cu(II) organic complex aqueous solutions is [Cu(HOC6H4COO)]+·(H2O)42 > [Cu(CH3CH2COO)]+·(H2O)42 > [Cu(COOHCOO)]+·(H2O)42. The calculation also found that for Cu(I) complex aqueous solutions, the difference in Cu isotope fractionation parameters (1000lnβ) between [CuCl2]−·(H2O)42 and [Cu(HS)2]−·(H2O)42 is relatively large. At 100 °C, the 1000lnβ of the two species are 1.14 and 1.55 (‰), respectively. The difference between the two could be reached up to 0.41 (‰). The Cu isotope fractionation parameter obtained with the “water droplet” method is also very different from the results of previous studies, which indicate that the Cu isotope fractionation behavior of the two is similar. At the same time, the exciting discovery is that the enrichment capacity of heavy Cu isotopes is significantly different between Cu(I) complex aqueous solutions and Cu(II) complex aqueous solutions. At 100 °C, the 1000lnβ of 6 Cu(I) complex aqueous solutions and 13 Cu(II) complex aqueous solutions ranged from 0.90 to 1.55 and 2.24 to 3.25(‰), respectively. It also shows that the REDOX reaction has a significant effect on the Cu isotope fractionation, especially in ore-forming fluids. Therefore, the ligand type is a factor that cannot be ignored when considering the mechanism of Cu isotope fractionation in solution/hydrothermal solution systems. Whether the solvation effect of an aqueous solution is considered or not has a great influence on the numerical values of the final Cu isotope fractionation factors. Hence, the solvation effect of an aqueous solution is an essential determinant in the theoretical calculation of the Cu isotope fractionation factors for Cu-bearing complex solutions.

A microfluid-assisted solution field-effect transistor (FET) with nanoscale channels of atomically thin MoS2 layers was constructed. The source–drain current (Id) vs gate voltage (Vg) characteristics (Id–Vg) were examined with a focus on the threshold voltage (Vth) at the onset of the Id–Vg curve. Id–Vg changed when the channel contacted the tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) solutions in isopropyl alcohol (IPA), acetonitrile (ACN), and dimethyl sulfoxide (DMSO). The shift in Vth from the pure solvent condition (ΔVth) increased monotonically with the concentration, which was successfully simulated using Langmuir-type adsorption kinetics. We conclude that the TCNQ and F4-TCNQ solutes were partially solvated by the solvent and adsorbed on the MoS2 channel. Simultaneously, the saturated ΔVth value revealed a significant difference between the TCNQ and F4-TCNQ solutes. The ratio of saturated ΔVth of F4-TCNQ compared to that of TCNQ showed a decrease of 4.2, 1.7, and 1.3 for IPA, ACN, and DMSO, respectively. These results coincided with the order of the dielectric constants of these solvents (18.0, 36.0, and 46.6, respectively). The solutes produced the Id–Vg curve by both charge transfer and the gating effect, the latter of which was screened by the presence of a solvent. This study demonstrates that a solution FET can be employed in solid–solution interface chemistry. [ABSTRACT FROM AUTHOR]

Alloy‐based anodes have shown great potential to be applied in sodium‐ion batteries (SIBs) due to their high theoretical capacities, suitable working potential, and abundant earth reserves. However, their practical applications are severely impeded by large volume expansion, unstable solid‐electrolyte interfaces (SEI), and sluggish reaction kinetics during cycling. Herein, a surface engineering of tin nanorods via N‐doped carbon layers (Sn@NC) and an interface engineering strategy to improve the electrochemical performance in SIBs are reported. In particular, the authors demonstrate that uniform surface modification can effectively facilitate electron and sodium transport kinetics, confine alloy pulverization, and simultaneously synergize interactions with the ether‐based electrolyte to form a robust organic‐inorganic SEI. Moreover, it is discovered that the diethylene glycol dimethyl ether electrolyte with strong stability and an optimized Na+ solvation structure can co‐embed the carbon layer to achieve fast reaction kinetics. Consequently, Sn@NC anodes deliver extra‐long cycling stability of more than 10 000 cycles. The full cell of Na3V2(PO4)3║Sn@NC exhibits high energy density (215 Wh kg−1), excellent high‐rate capability (reaches 80% capacity in 2 min), and long cycle life over a wide temperature range of −20 to 50 °C. [ABSTRACT FROM AUTHOR]

Protein unfolding is a ubiquitous process responsible for the loss of protein functionality (denaturation), which, in turn, can be accompanied by the death of cells and organisms. The nature of enthalpy–entropy compensation (EEC) in the kinetics of protein unfolding is a subject of debate. In order to investigate the nature of EEC, the "completely loose" transition state (TS) model has been applied to calculate the Arrhenius parameters for the unfolding of polyglycine dimers as a model process. The calculated Arrhenius parameters increase with increasing dimer length and demonstrate enthalpy–entropy compensation. It is shown that EEC results from the linear correlations of enthalpy and entropy of activation with dimer length, which are derived directly from the properties of the transition state. It is shown that EEC in solvated (hydrated, etc.) proteins is a direct consequence of EEC in proteins themselves. The suggested model allows us also to reproduce and explain "exotic" very high values of the pre-exponential factor measured for the proteins unfolding, which are drastically higher than those known for unimolecular reactions of organic molecules. A similar approach can be applied to analyzing the nature of EEC phenomena observed in other areas of chemistry. [ABSTRACT FROM AUTHOR]

[Display omitted] • Solvation significantly affects energy of species on IIIB-VB TM@GDY, less on VIII/IB. • The performances of OER/ORR are enhanced at Δ G OH* <0.80 eV by weakening OH adsorption. • OER/ORR activities are improved at Δ G OH* >0.90 eV by strengthening OH adsorption. • Find a universal structure descriptor φ with the intrinsic features of the elements. • Ni@GDY, Co@GDY and Cu@GDY are trifunctional electrocatalysts for OER, ORR and HER. Efficient single-atom electrocatalysts show great potential for application in the field of renewable energy. In this work, dispersion-corrected density functional theory (DFT) calculations based on high-throughput screening were used to identify effective graphdiyne (GDY) supported single-atom electrocatalysts (SAECs) for water electrolysis and the oxygen reduction reaction (ORR). The solvation effect on the electrocatalytic performance of the catalysts was carefully discussed. A general design principle was established to evaluate the activities of TM@GDY SAECs for ORR and oxygen evolution reaction (OER). Δ G OH* could serve as the sole descriptor for the onset potential of OER and ORR. Additionally, a universal structural descriptor φ, which is strongly related to Δ G OH* , was identified. This descriptor only includes intrinsic features such as the number of electrons in d orbitals and elemental electronegativity. Consequently, a structure-activity volcano was plotted. Combined with the electronic properties calculations, the mechanism behind the relationship between Δ G OH* and descriptor φ was deeply analyzed. Among the investigated candidates, TM@GDY (TM = Ni, Pt, Pd, Cu, Co, Rh, and Ag) are potential bifunctional electrocatalysts for OER and ORR. Three non-noble metal-based SAECs (Ni@GDY, Co@GDY, and Cu@GDY) and two noble metal-based SAECs (Rh@GDY and Ag@GDY) are potential trifunctional electrocatalysts for OER, ORR, and the hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

As the most productive thermosetting polymer, unsaturated polyester resin (UPR) and its composies were difficult to be chemcycled due to the mass transfer barrier in dense network structure. High temperature/pressure and mechanical crushing were usually applied to improve the mass transfer during chemcycling processes, but at the sacrifice of reaction selectivity and fiber integrity. Here, a unique fragmentation effect of aprotic solvents was observed in UPR, which is a non-reactive solvation that has the potential to replace mechanical fragmentation and improve the recyclability of UPR and its composite materials. The solvation was found to be based on the hydrogen bond between the solvent and ester group of UPR through Hansen solubility parameters and molecular dynamics simulation. It was the intermolecular force between the polyester clusters of UPR that was destroyed, leading to the fragmentation of UPR into micron-sized powder. The fragmentation effect is also applicable to other ester-containing polymers and provides a simple, facile, and energy-efficient method for the chemcycling of thermosetting resins, as well as direct exfoliation of reinforced fillers. A simple solvation method is used to achieve non-reactive fragmentation of thermosets at a low temperature. It is a promising avenue to improve mass transfer and promote degradation efficiency in recovery of thermosets and non-destructive fibers. [Display omitted] • UPR fragmentation/non-deconstructive fiber exfoliation achieved in aprotic solvent. • Solvation is attributed to formation of hydrogen bonds between solvent and ester. • Hansen solubility parameter sphere for the solvation of UPR was established. • Fragmentation effect of solvent is applicable to other ester-containing polymers. [ABSTRACT FROM AUTHOR]

As a key component of batteries, the electrolyte determines the ion transport and interface chemistry of the cathode and anode. In this work, we develop a dual‐network structured hydrogel electrolyte composed of polyacrylamide (PAM), sodium alginate (SA) and potassium iodide (KI) for solid‐state zinc‐air/iodide hybrid batteries. The assembled hybrid battery shows excellent renewability and a long cycling life of 110 h with a high energy efficiency of 80 %. The ion‐crosslinked dual‐network structure endows the material with improved mechanical strength and increased ionic conductivity. More importantly, the introduction of iodine species not only offers more favorable cathodic kinetics of iodide/iodate redox than oxygen electrocatalysis but also regulates the solvation structure of zinc ions to ensure better interface stability. This work provides significant concepts for developing novel solid‐state electrolytes to realize high‐performance energy devices and technologies. [ABSTRACT FROM AUTHOR]

As a rare sugar, D-Tagatose is regarded as an excellent low-energy food sweetener. It is especially beneficial for physical health, such as inhibiting hyperglycemia, improving intestinal flora, and avoiding caries. It is broadly employed in food, medicine, cosmetics, and other fields. Acquiring D-Tagatose solubility is vital to develop D-Tagatose crystallization process to obtain high-quality D-Tagatose production. In this study, the solubility of D-Tagatose in seven pure solvents (methanol, ethanol, n-propanol, water, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone), three binary solvents (ethanol-water mixtures, ethanol-methanol mixtures, and n-propanol-water mixtures) was determined by HPLC method at temperatures from 293.15 K to 323.15 K. Then, the Van't Hoff equation, Apelblat equation, λh equation, NRTL equation, CNIBS/Redlich-Kister model and modified Jouyban-Acree-van't Hoff model were used to correlate the solubility. The correlated solubility accounted for suitable compatibility with the experimental results (ARD

Abstract Magnesium metal anode holds great potentials toward future high energy and safe rechargeable magnesium battery technology due to its divalent redox and dendrite-free nature. Electrolytes based on Lewis acid chemistry enable the reversible Mg plating/stripping, while they fail to match most cathode materials toward high-voltage magnesium batteries. Herein, reversible Mg plating/stripping is achieved in conventional carbonate electrolytes enabled by the cooperative solvation/surface engineering. Strongly electronegative Cl from the MgCl2 additive of electrolyte impairs the Mg…O = C interaction to reduce the Mg2+ desolvation barrier for accelerated redox kinetics, while the Mg2+-conducting polymer coating on the Mg surface ensures the facile Mg2+ migration and the effective isolation of electrolytes. As a result, reversible plating and stripping of Mg is demonstrated with a low overpotential of 0.7 V up to 2000 cycles. Moreover, benefitting from the wide electrochemical window of carbonate electrolytes, high-voltage (> 2.0 V) rechargeable magnesium batteries are achieved through assembling the electrode couple of Mg metal anode and Prussian blue-based cathodes. The present work provides a cooperative engineering strategy to promote the application of magnesium anode in carbonate electrolytes toward high energy rechargeable batteries.

The redox potential is a fundamental parameter in electrochemistry and is essential in understanding energy-related applications. A typical redox-active molecule, 2,2,6,6-tetramethyl piperidine-1-oxyl (TEMPO), which has an electrocatalytic effect on organic molecules and functions as a mediator in battery technologies, was selected as a model to investigate the dependence of redox potential on the concentration of the supporting electrolyte LiTFSI. Unusual results from cyclic voltammetry have been obtained, showing that the redox potential of TEMPO shifts negatively upon increasing the concentration of LiTFSI. Solvation energy changes from the tunability of dielectric constants and ion pairing are proposed to explain the phenomenon. This work provides insights into tuning the redox potential through simple methods, with applications in the fields of electrocatalysis and battery technology.

The performance of electrode material is correlated with the choice of electrolyte, however, how the solvation has significant impact on electrochemical behavior is underdeveloped. Herein, N‐heteropentacenequinone (TAPQ) is investigated to reveal the solvation effect on the performance of sodium‐ion batteries in different electrolyte environment. TAPQ cycled in diglyme‐based electrolyte exhibits superior electrochemical performance, but experiences a rapid capacity fading in carbonate‐based electrolyte. The function of solvation effect is mainly embodied in two aspects: one is the stabilization of anion intermediate via the compatibility of electrode and electrolyte, the other is the interfacial electrochemical characteristics influenced by solvation sheath structure. By revealing the failure mechanism, this work presents an avenue for better understanding electrochemical behavior and enhancing performance from the angle of solvation effect. [ABSTRACT FROM AUTHOR]

Electronic structure and catalytic activity in hydrogen evolution reactions (HER) of two ternary tri-chalcogenide nano-ribbons, MnPSe 3 and FePSe 3 , have been investigated using first-principles electronic structure calculations. Specific edge sites have been identified as the catalytic centers in both these materials. HER catalytic activity has been predicted through determination of the hydrogen adsorption free energy following Nørskov's approach. This has been done both with and without considering effects of the aqueous solvent. Hydrogen coverage dependency of the catalytic activity have also been studied. Identification of the catalytically active edge sites on these materials bridges experimental observations and theoretical predictions on these materials. • Theory-experiment contradiction about HER activity of MnPSe 3 and FePSe 3 addressed. • Catalytic activity of edge atoms in two materials studied. • Active site identified in low and high hydrogen coverage, resolving the contradiction. • Effect of aqueous solvent included for realistic estimate of catalytic activity. • Ways of further increasing catalytic activity of the materials suggested. [ABSTRACT FROM AUTHOR]

The development of artificial molecular catalysts for CO2 reduction is the key to solving energy and environmental problems. Although chemical modifications can generally improve the catalytic activity of this class of compounds, they often require complicated synthetic procedures. Here, we report a simple procedure that dramatically enhances electrochemical CO2 reduction activity. A one‐step counteranion‐exchange reaction increased the solubility of a commercially available catalyst, iron(III) tetraphenylporphyrin chloride, in a variety of solvents, allowing the investigation of its catalytic performance under various conditions. Surprisingly, the turnover frequency for CO evolution in acetonitrile (MeCN) reached 7 300 000 s−1, which is the highest among those of current best‐in‐class molecular catalysts. This excellent catalytic activity originates from the unique reaction between the generated FeI species and CO2 in MeCN during catalysis. The present study offers a "quick and easy" method for obtaining an efficient catalytic system for electrochemical CO2 reduction. [ABSTRACT FROM AUTHOR]

The development of artificial molecular catalysts for CO2 reduction is the key to solving energy and environmental problems. Although chemical modifications can generally improve the catalytic activity of this class of compounds, they often require complicated synthetic procedures. Here, we report a simple procedure that dramatically enhances electrochemical CO2 reduction activity. A one‐step counteranion‐exchange reaction increased the solubility of a commercially available catalyst, iron(III) tetraphenylporphyrin chloride, in a variety of solvents, allowing the investigation of its catalytic performance under various conditions. Surprisingly, the turnover frequency for CO evolution in acetonitrile (MeCN) reached 7 300 000 s−1, which is the highest among those of current best‐in‐class molecular catalysts. This excellent catalytic activity originates from the unique reaction between the generated FeI species and CO2 in MeCN during catalysis. The present study offers a “quick and easy” method for obtaining an efficient catalytic system for electrochemical CO2 reduction. [ABSTRACT FROM AUTHOR]

The bis(chloro)-bis(1,10-phenanthroline)-manganese(II) crystalline complex, with the formula [Mn(phen) 2 Cl 2 ], was synthesized by slow evaporation method. Structural, thermal, and vibrational properties of the crystal were obtained by X-ray powder diffraction (XRPD), thermal analysis, Raman, and Fourier-transform infrared (FT-IR) spectroscopy. XRPD results showed that the crystal belongs to a monoclinic system with P 2 1 / c (C 2 h 5) space group. Thermal analyses revealed that the material presents good stability within 300–558 K temperature interval. In addition, Hirshfeld surface analysis revealed the sites involved in intermolecular interactions predominant in the crystal. Also, all Raman and IR-active bands were assigned from computational calculations based on density functional theory (DFT) to analyze intramolecular vibration modes. Additionally, the electronic and vibrational properties were investigated considering three different media (vacuum, methanol, and water) using the integral equations formalism of the polarizable continuum model (IEFPCM). Lastly, the bactericidal assays on Staphylococcus aureus (ATCC 6538), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) e Enterococcus faecalis (ATCC 25923) were carried out to evaluate the antimicrobial activity of this complex. [Display omitted] • A [Mn(1,10-phenanthroline) 2 Cl 2 ] complex was synthesized by low evaporation method using a mixed solution of water-methanol. • Solvation effects on the structural, electronic, and vibrational properties were evaluated. • Hirshfeld surfaces showed that the main intermolecular contacts are H∙∙∙H, C∙∙∙H/H∙∙∙C, and Cl∙∙∙H/H∙∙∙Cl. • Vibrational modes were studied by FT-IR and Raman spectroscopy and analysed by DFT calculations. • The [Mn(1,10-phenanthroline) 2 Cl 2 ] complex presented bactericidal and bacteriostatic activity against four microorganisms. [ABSTRACT FROM AUTHOR]

[Display omitted] • [Zn(NA) 2 Cl 2 ] complex, with monoclinic symmetry (P 2 1 /a) was successfully crystallized; • Solvation effect on structural and thermodynamic properties was studied by DFT using PBE1PBE and B3LYP functionals; • DFT allowed vibrational modes adequate assignments in FT-IR and Raman spectra under different solvation conditions; • The complex is thermally stable up to around 200 °C with a decomposition enthalpy of 335.27 kJ/mol; • [Zn(NA) 2 Cl 2 ] exhibited antibacterial activity against Gram-positive and Gram-negative bacteria. A dichlorobis(nicotinamide)zinc(II) complex, [Zn(nicotinamide) 2 Cl 2 ], was crystallized through the slow evaporation method, and its vibrational, electronic, structural, and thermal properties have been characterized. Density functional theory (DFT) was used for the accurate analysis of intramolecular vibrational modes, obtaining chemical reactivity indices and comparative studies of geometric and electronic parameters, including solvation effects in methanol, ethanol, and water, as well as in vacuum. Additionally, the nature and strength of the bonds associated with the coordination sphere (Cl–Zn and N–Zn) were elucidated from the quantum theory of atoms in molecules and natural bond orbital analyses. Powder X-ray diffraction showed that the coordination compound belongs to a monoclinic symmetry with P 2 1 / a (C 2 h 5) space group. Thermal analyses revealed that the material is stable up to 200 °C. From DFT calculations, the complex is chemically more stable in solvents compared to vacuum conditions, with the aqueous medium offering greater stability. The chemical stability was also analyzed by infrared and Raman spectroscopy, with the results showing spectral changes mainly for the vibrational spectra obtained in methanol, ethanol, and water against those obtained in vacuum. Biological experiments showed the complex antibacterial activity against Gram-positive and Gram-negative bacteria, mainly against the Cutibacterium acnes ATCC 6919 strain. A computational study of the absorption, distribution, metabolism, excretion (ADME), and drug-likeness were calculated to support the experimental data. [ABSTRACT FROM AUTHOR]

The synthesis and X-ray structure of a novel glycoluril derivative are described. The crystal of the glycoluril derivative is obtained by slow evaporation in a refrigerator at about 5 °C. X-ray crystallographic analysis revealed that the compound crystallized in an unusual as conformation instead of the usual clip-shaped aa conformation. Structural analysis shows that the solvation effect, hydrogen bonding, and space-occupying effect influenced the crystallization conformation of the derivative. The X-ray crystallographic analysis in this work provides additional crystallographic evidence of the as conformation of the 3U glycoluril derivative and shows the effect of solvent water on the conformational behavior. [ABSTRACT FROM AUTHOR]

Four spirooxazine compounds were synthesized, and their structures were characterized by FTIR, ¹H NMR, and ESI-MS. The effects of different substituents on the nitrogen atom of the indole ring and the 9'-position of the oxazine ring and the solvation effect on the photochromic properties were studied. The results show that the bulky group on the indole nitrogen atom has no significant effect on the maximum absorption wavelength, but it is beneficial to the stability of the PMC and the introduction of bromine atoms can reduce the light responsiveness of spirooxazine. The electron-donating group at the 9'-position of the oxazine ring can reduce the stability of the PMC. Moreover, the fading process of the spirooxazine conforms to the first-order kinetic equation. In aprotic solvents, the λmax of PMC is positively correlated with solvent polarity. The addition of organic acid can increase the thermal stability of the PMC. [ABSTRACT FROM AUTHOR]

Highlights: A cooperative solvation/surface engineering approach is reported to achieve the reversible Mg plating/stripping in conventional carbonate electrolytes. Benefitting from the strategy, Mg2+ can easily overcome the reduced desolvation barrier and penetrate the Mg2+-conducting polymer coating, deposited on the Mg metal anode successfully, promoting the application of magnesium anode in carbonate electrolytes toward high-energy rechargeable batteries.Magnesium metal anode holds great potentials toward future high energy and safe rechargeable magnesium battery technology due to its divalent redox and dendrite-free nature. Electrolytes based on Lewis acid chemistry enable the reversible Mg plating/stripping, while they fail to match most cathode materials toward high-voltage magnesium batteries. Herein, reversible Mg plating/stripping is achieved in conventional carbonate electrolytes enabled by the cooperative solvation/surface engineering. Strongly electronegative Cl from the MgCl2 additive of electrolyte impairs the Mg…O = C interaction to reduce the Mg2+ desolvation barrier for accelerated redox kinetics, while the Mg2+-conducting polymer coating on the Mg surface ensures the facile Mg2+ migration and the effective isolation of electrolytes. As a result, reversible plating and stripping of Mg is demonstrated with a low overpotential of 0.7 V up to 2000 cycles. Moreover, benefitting from the wide electrochemical window of carbonate electrolytes, high-voltage (> 2.0 V) rechargeable magnesium batteries are achieved through assembling the electrode couple of Mg metal anode and Prussian blue-based cathodes. The present work provides a cooperative engineering strategy to promote the application of magnesium anode in carbonate electrolytes toward high energy rechargeable batteries. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes have emerged as promising alternatives to current liquid electrolytes due to their advantages in battery safety and stability. Among various polymer electrolytes, poly(vinylidene fluoride) (PVDF)‐based electrolytes with high ionic conductivity, large mechanical strength, and excellent electrochemical and thermal stability have a great potential for practical applications. However, fundamental issues, such as how the Li ions transport in the PVDF‐based electrolytes and how the residual solvent affects the cell performance, are unclear. Here, we demonstrate that the solvation effect due to a small amount of residual N,N‐dimethylformamide (DMF) bound into the electrolytes plays a critical role in ionic transport, interface stability, and cell performance. With the residual DMF existing in the electrolytes in a bound state not as free solvent, the ionic conduction could be realized by the Li‐ion transport among the interaction sites between the bound DMF and PVDF chains. Regulating the solvation effect in the electrolytes can make the PVDF‐based solid‐state Li metal batteries a significantly improved cycling performance at 25 °C (e. g. over 1000 cycles with a capacity retention of more than 94 %). These findings would promote the development of next‐generation Li metal batteries with high energy density and safety. [ABSTRACT FROM AUTHOR]

To understand the substitution effects of 2-acylpyridine on the reaction equilibrium, the coordination interaction between a series of 2-acylpyridine derivatives and peroxovanadium(V) complex [OV(O2)2(D2O)]−/[OV(O2)2(HOD)]− in solution was explored by the combined use of multinuclear (1H, 13C, and 51V) magnetic resonance, COSY, together with HSQC in 0.15 M NaCl ionic medium for mimicking the physiological conditions. Some direct NMR data are given for the first time. The relative reactivity among the 2-acylpyridine derivative ligands is 2-acetylpyridine (1) > 2-propionylpyridine (2) > 2-butyrylpyridine (4) > 2-isobutyrylpyridine (3). The competitive coordination results in the formation of a series of new seven-coordinate peroxovanadium species [OV(O2)2L]− (L = 1, 2, 3, and 4). The results of density functional calculations indicated that the solvation effects play an important role in these reactions, providing a reasonable explanation on the relative reactivity of the 2-acylpyridine derivative. [ABSTRACT FROM AUTHOR]

Two new difluoroboron β‐carbonyl cyclic ketonate complexes C2B and DC2B were investigated using several spectroscopic methods. Relative to the absorption spectra, the fluorescence spectra were more affected by the polarity of the solvent. Also, compound C2B showed a more pronounced Stokes' shift after solvent polarity increased. Transient absorption measurements then demonstrated the relaxation behaviour of the excited state compound molecule. The kinetic results showed that the excited state C2B in tetrahydrofuran (THF) can return from the intramolecular charge‐transfer (ICT) state and the initial excited state to the ground state. The kinetic relaxation pathway after THF was replaced by dimethyl sulfoxide became single. When the carbazole unit was introduced, DC2B also exhibited an ICT state but there was no significant difference in the excited state relaxation path after solvent polarity was changed. The results indicated that C2B is more susceptible to solvent polarity regulation. The global fit results revealed that an increase in the solvent polarity prolonged the lifetime of the ICT state of compound C2B and had the opposite effect on compound DC2B. These results provide guidance for understanding the relationship between solvent polarity and the designing and synthesizing advanced compound materials. [ABSTRACT FROM AUTHOR]

Gaining an understanding of the conformational behavior of fluorinated compounds would allow for expansion of the current molecular design toolbox. In order to facilitate drug discovery efforts, a systematic survey of a series of diversely substituted and protected fluorinated piperidine derivatives has been carried out using NMR spectroscopy. Computational investigations reveal that, in addition to established delocalization forces such as charge–dipole interactions and hyperconjugation, solvation and solvent polarity play a major role. This work codifies a new design principle for conformationally rigid molecular scaffolds. [ABSTRACT FROM AUTHOR]

• The tetra-oxygen path mechanism (t-OPM) on NiFe-LDH catalyst was mainly investigated in two paths. • The OER performance was studied when surface 2O as active sites were under 0 ∼ 6 environment oxygen (O ev) exposure. • Based on the t-OPM, the minimum overpotential for OER process was 0.07 eV on O ev-346 model. • The OER performed of models with 2 ∼ 4 O ev exposure was better than the rest. The oxygen evolution reaction (OER) with large overpotential is the bottleneck of the whole water electrolysis process. NiFe layered double hydroxide (NiFe-LDH) represent one of the potential catalysts for OER in alkaline media. For the LDH, it was well established that both adsorption evolution mechanism and lattice oxygen mechanism could appear at a single site, but Ni-OOOO-Fe species would provide a different O O path mechanism at dual-O sites due to the complexity and diversity of LDH surface. Here, using first-principles study, tetra-oxygen path mechanism (t-OPM) was proposed to investigate the OER performance of NiFe-LDH by considering surface 2O were as active sites (O ac) and other O as environment O (O ev) with different exposed degrees (0–6). It was found that the optimal performance of the NiFe-LDH surface could be achieved when 2 ∼ 4 O ev were exposed under the explored mechanism in different paths (path 1 and path 2) with overpotential η = 0.07 ∼ 0.35 V, and path 1 was slightly better than path 2. At the same time, the solvation effect (SE) was used to study the effect on the OER performance, the results showed that SE had a little influence on the case of 2 ∼ 4 O ev exposed while had a large effect on the other cases. The detailed analysis of the electronic structure showed a smaller difference Δ ε between the energy Fe-3d band center and O ac -2p, which imply the stronger the interaction between them. Thus, the t-OPM was feasible in OER on NiFe-LDH. It was anticipated that our work could provide a fresh perspective on the understanding of the excellent OER performance of LDH in alkaline environment, which was complementary to the traditional mechanism to some extent. [Display omitted] This work focused on the tetra-oxygen path mechanism (t-OPM) in oxygen evolution reaction on NiFe layered double hydroxides with surface 2O as active sites. [ABSTRACT FROM AUTHOR]

Abstract The reaction pathways of PCB-77 in the atmosphere with ·OH, O2, NO x , and 1O2 were inferred based on density functional theory calculations with the 6-31G* basis set. The structures the reactants, transition states, intermediates, and products were optimized. The energy barriers and reaction heats were obtained to determine the energetically favorable reaction pathways. To study the solvation effect, the energy barriers and reaction rates for PCB-77 with different polar and nonpolar solvents (cyclohexane, benzene, carbon tetrachloride, chloroform, acetone, dichloromethane, ethanol, methanol, acetonitrile, dimethylsulfoxide, and water) were calculated. The results showed that ·OH preferentially added to the C5 atom of PCB-77, which has no Cl atom substituent, to generate the intermediate IM5. This intermediate subsequently reacted with O2 via pathway A to generate IM5a, with an energy barrier of 7.27 kcal/mol and total reaction rate of 8.45 × 10−8 cm3/molecule s. Pathway B involved direct dehydrogenation of IM5 to produce the OH-PCBs intermediate IM5b, with an energy barrier of 28.49 kcal/mol and total reaction rate of 1.15 × 10−5 cm3/molecule s. The most likely degradation pathway of PCB-77 in the atmosphere is pathway A to produce IM5a. The solvation effect results showed that cyclohexane, carbon tetrachloride, and benzene could reduce the reaction energy barrier of pathway A. Among these solvents, the solvation effect of benzene was the largest, and could reduce the total reaction energy barrier by 25%. Cyclohexane, carbon tetrachloride, benzene, dichloromethane, acetone, and ethanol could increase the total reaction rate of pathway A. The increase in the reaction rate of pathway A with benzene was 8%. The effect of solvents on oxidative degradation of PCB-77 in the atmosphere is important. Graphical abstract The reaction pathways of PCB-77 in the atmosphere with •OH, O2, NOx, and 1O2 were inferred based on density functional theory calculations with the 6-31G* basis set. Different polar and nonpolar solvents: cyclohexane, benzene, carbon tetrachloride, chloroform, acetone, dichloromethane, ethanol, methanol, acetonitrile, dimethylsulfoxide, and water were selected to study the solvation effect on the favorable reaction pathways. The investigated results showed what kind of pathway was most likely to occur and the solvent effect on the reaction pathway

• An optimization-based framework is developed for reaction solvent design. • The reaction kinetic model is identified through a hybrid method based on CTST. • The GC-COSMO/GC methods are developed for the reaction kinetic model. • An MINLP model is established and a decomposition-based algorithm is applied. • Case studies indicate feasibility and effectiveness of the framework. Solvents have been widely used in chemical manufacturing processes. When involved in liquid homogeneous-phase kinetic reactions, they can have significant impacts on the reaction product yield. In this paper, an optimization-based framework is developed for reaction solvent design. The framework first identifies a reaction kinetic model using a hybrid method consisting of three steps. In step one, a rigorous thermodynamic derivation based on CTST (Conventional Transition State Theory) is performed to formulate a primary reaction kinetic model. In step two, a knowledge-based method is used to select additional solvent properties as supplementary descriptors to account for quantitative correction to the model and thereby improving the prediction accuracy. In step three, model identification is performed to obtain the best regressed reaction kinetic model. This hybrid modelling method is tested through two case studies, namely Diels-Alder and Menschutkin reactions, and an impressive consistency of the results is observed when the infinite dilution activity coefficients (calculated by COSMO-SAC model), hydrogen-bond donor, hydrogen-bond acceptor and solvent surface tension are selected as descriptors in the final reaction kinetic model. The GC-COSMO and GC (Group Contribution) methods are combined for the prediction of these descriptors. Finally, the Computer-Aided Molecular Design (CAMD) technique is integrated with the derived kinetic model for reaction solvent design by formulating and solving a Mixed-Integer Non-Linear Programming (MINLP) model. A decomposition-based solution algorithm is employed to manage the complexity involved with the nonlinear COSMO-SAC equations. Promising reaction solvents are identified and compared with those reported by others, indicating wide applicability and high accuracy of the developed optimization-based framework. [ABSTRACT FROM AUTHOR]

Of Hex1 is a potential target for the rational design of pesticides. TMG-chitotriomycin is one of the most highly specific known inhibitors of chitinolytic β-GlcNAcases from bacteria, fungi and insects. TMG-chitotriomycin and its analogues show different activities to O f Hex1, dependent on the number of GlcNAc units. Subsequently, it is essential to explore how these GlcNAc unit number changes cause alterations in activity. In this study, we examined the free energy patterns and per residue decomposition of binding within the complexes of Of Hex1 and a series of inhibitors, utilizing restricted molecular dynamics (MD) and water-mediated MM/GBSA calculations. The results indicated Glu328 could form a stronger polar interaction with Of Hex1 inhibitors, while Trp448 and Trp490 had important non-polar contributions. Interestingly, the conformation of Trp448 was different in the open or closed state, when O f Hex1 bound different inhibitors. Moreover, the water molecule that mediates the GlcNAc Ⅱ and Trp490 may be critical to stabilizing the hydrophobic interaction. Further study showed that isomerization of TMG-chitotriomycin analogs did not decrease binding affinity, however, there was a highly positive correlation between the calculated binding affinities and the experimental activity data (r2 = 0.92) when water molecules were explicitly taken into account. Moreover, the water molecules that mediated GlcNAc II and Trp490 might be critical to the stabilization of the hydrophobic interaction and cause the activity difference between TMG-(GlcNAc) 2 and TMG-(GlcNAc). Image 1 • The correlation between binding free energy and experimental values calculated by MM/GBSA was high (r2 = 0.91). • Explicit water molecules were considered to calculate the binding free energy with MM/GBSA. • An important water molecule mediates the second GlcNAc II and Trp490. [ABSTRACT FROM AUTHOR]

[Display omitted] • The excellent nonlinear optical (NLO) properties are obtained in acetonitrile solvent by theoretical calculating. • The β tot value of c-MeCN is about 12 times as large as that of o-MeCN , which provide a basis for NLO switch. • The UV–visible absorption spectrum can confirm that the remarkable β tot values for c-MeCN are mainly attributed to the charge transfer induced by the photocyclization. • The range of differences for β tot values is about from 7 to 12 times in different solvents, when the complexes open and close form convert to each others. In 2009, the interesting photochromic complex o-MeCN and its isomeric close form c-MeCN were synthesized and investigated, which would transform to each other according to the characterization of UV and visible irradiation. In our work, the excellent nonlinear optical (NLO) properties are obtained by theoretical calculating. Results show that the β tot value of c-MeCN is about 12 times as large as that of o-MeCN in acetonitrile solvent, which provide a basis for NLO switch. Further, the UV–visible absorption spectrum can confirm that the remarkable β tot values for c-MeCN are mainly attributed to the charge transfer induced by the photocyclization. Significantly, the β tot values reduced with the increasing of dielectric constant ε of the solvent, and the differences of β tot values between the open and close form, present a regularly change in different solvents. This reversible photochromic process and solvent effect may open up new opportunities for the discovery of attractive NLO switch. [ABSTRACT FROM AUTHOR]