Effect of Ionic Liquid on Retention of Solutes on C_(18) Column Based on Linear Solvation Energy Relationships

Several chromatography systems with ionic liquids and a mixture of water with the modifier as mobile phase were characterized via the linear solvation energy relationships（LSER） model. The effects of the ionic liquids and modifier（methanol） concentrations on the retention of 10 solutes（caffeine, pyridine, aniline, phenol, methylparaben, acetopenone, m-cresol, p-cresol, o-cresol, and benzene） were discussed. The LSER model demonstrated high potential to predict retention factors with high squared correlation coefficients（r^2〉 0.97）. A comparison of predictable and experimental retention factors revealed that LSER can adequately reproduce the experimental retention factors of the solutes under different investigated experimental conditions. This model is a helpful tool to evaluate the retention characteristics of ionic liquid systems and to understand the interactions of solutes and ionic liquids.

A high-capacity viologen-based anolyte for high energy density neutral pH aqueous redox-flow batteries

Redox-flow batteries(RFBs)are a promising energy storage technology with remarkable scalability and safety for storing vast amounts of renewable energy and mitigating outputfluctuations of renewable power grids.We demonstrate a neutral pH aqueous RFB using a custom-designed 1’,1’’’,1’’’’’-(benzene-1,3,5-triyltris(methylene))tris(1-(3-(trimethyl ammonio)propyl)-[4’’,4’’’-bipyridine]-1,1’-diium)nonachloride(BTTMPB)as a 3 e-storage anolyte.The custom design with the high polarization in charge density has led to the excellent water solubility of 4.0 M in H_(2)O(321.6 A h L^(-1))and 2.4 M in 2.0 M NaCl(192.9 A h L^(-1)).The density functional theory(DFT)calculations and electrochemical experiments have shown 3 e-storage response of BTTMPB with a diffusion coefficient of 3.1×10^(-6)cm^(2) s^(-1)and rate con-stant of 1.6×10^(-2)cm s^(-1) for thefirst reduction process.The synthesized anolyte was paired with(Ferrocenylmethyl)trimethylammonium chloride(FcNCl)as catholyte enabling a 0.92 V aqueous RFB with 125.9 W h L^(-1)theoretical energy density.The aqueous RFB has an excellent cycling performance from 10-30 m A cm^(-2),energy efficiency up to 80%,capacity retention of 99.96%per cycle at 20 m A cm^(-2),and a high demonstrated energy density of 29.1 W h L^(-1).

Predicting octanol/water partition coefficient using solvation free energy and solvent-accessible surface area

The regression model for octanol/water partition coefficients ( K ow ), is founded with only two molecular descriptors available through quantum chemical calculations: solvation free energy (Δ G S ), and solvent accessible surface area (SASA). For the properties of 47 organic compounds from 17 types, the model gives a correction coefficient (adjusted for degrees of freedom) of 0 959 and a standard error of 0 277 log unit. It is a suitable way to predict the partition properties that are related to solute solvent interactions in the water phase.

Time-Dependent Stokes Shift from Solvent Dielectric Relaxation

The Stokes shift response function, which is related to the time dependent solvation energy, is calculated with the dielectric response function and a novel expression of nonequilibrium solvation energy. In the derivation, relationship between the polarization and the dielectric response function is used. With the dipole-in-a-sphere model applied to the system coumarin 343 and water as the solvent, encouraging agreement with the experimental data from Jimenez et al. is obtained [Nature 369, 471 （1994）].

Application of TLSER method in predicting the aqueous solubility and n-octanol/water partition coefficient of PCBs,PCDDs and PCDFs

The theoretical linear solvation energy relationship(TLSER) approach was adopted to predict the aqueous solubility and n -octanol/water partition coefficient of three groups of environmentally important chemicals-polychlorinated biphenyls(PCBs), polychlorinated dibenzodioxins and dibenzofurans(PCDDs and PCDFs). For each compound, five quantum parameters were calculated using AM1 semiempirical molecular orbital methods and used as structure descriptors: average molecular polarizability(α), energy of the lowest unoccupied molecular orbit( E _ LUMO ), energy of the highest occupied molecular orbit( E _ HOMO ), the most positive charge on a hydrogen atom( q _+), and the most negative atomic partial charge( q _-) in the solute molecule. Then standard independent variables in TLSER equation was extracted and two series of quantitative equations between these quantum parameters and aqueous solubility and n -octanol/water partition coefficient were obtained by stepwise multiple linear regression(MLR) method. The developed equations have both quite high accuracy and explicit meanings. And the cross-validation test illustrated the good predictive power and stability of the established models. The results showed that TLSER could be used as a promising approach in the estimation of partition and solubility properties of macromolecular chemicals, such as persistent organic pollutants.

Quantitative Correlation of Chromatographic Retention and Acute Toxicity for Alkyl(1-phenylsulfonyl) Cycloalkane Carboxylates and Their Structural Parameters by DFT

Twenty eight alkyl(1-phenylsulfonyl) cycloalkane carboxylates were computed at the B3LYP/6-31G* level. Based on linear solvation energy theory, two quantitative correlation equations of the molecular structures of alkyl(1-phenylsulfonyl) cycloalkane carboxylate com- pounds to their chromatographic retention (capacity factor lgKW) and the toxicity for photo- bacterium phosphoreum (–lgEC50) were developed by using the molecular structural parameters as theoretical descriptors (r2 = 0.9501, 0.9488). The two quantitative correlation equations were consequently cross validated by leave-one-out (LOO) validation method with q2 of 0.9113 and 0.9281, respectively. The result showed that the two equations achieved in this work by B3LYP/6-31G* are both more advantageous than those from AM1, and can be used to predict the lgKW and –lgEC50 of congeneric organics.

QSPR Studies on lgK_(ow) and lgK_(oc) of Fluorobenzenes and Property Parameters Based on HF and DFT Calculations

Quantum chemistry parameters of 22 fluorobenzenes were computed at six levels using Hartree-Fock and DFT methods. Based on the experimental data of n-octanol/water partition coefficient （lgKow）, a three-parameter （dipole moments （μ）, zero point energy （ZPE） and free energy （G°）） quantitative correlation equation that can predict IgKow was developed using structural and thermodynamic parameters as theoretical descriptors. Similarly, based on experimental data of soil organic carbon sorption coefficient （lgKoc）, the other three-parameter （the most negative atomic net charge of molecule （q^-）, dipole moments （μ） and molecular volume （Vi）） quantitative correlation equation that can predict lgKoc was given. Quantitative correlation equations based on B3LYP/6- 311 G^＊＊ calculation were validated by VIF （variance inflation factors） and t-test and used to predict IgKow and lgKoc of a series of compounds. The result showed that the correlation and prediction ability of lgKoc equations based on three levels of HF/STO-3G, B3LYP/6-31 G^＊ and B3LYP/6- 311G^＊＊ are all more advantageous than those based on AMI.

Quantitative Correlation of the Acute Toxicity of Phenylthio-carboxylates with Their Structural and Thermodynamic Parameters by DFT Calculation

Phenylthio-carboxylates were computed at the B3LYP/6-31G* level with DFT method. Based on linear solvation energy theory, the structural parameters were firstly taken as theoretical descriptors, and the corresponding linear solvation energy relationship (LSER) equation (r = 0.8989) to the toxicity of photobacterium phosphoreum (–lgEC50) was thus obtained. Then the structural and thermodynamic parameters were taken as theoretical descriptors, and as a result the other corresponding correlation equation (r = 0.9274) relating to –lgEC50 was provided. The two equations achieved in this work by B3LYP/6-31G* are both more advantageous than that from AM1.

Theoretical Researches on the Self-assembly System of Ciprofloxacin Imprinted Polymers

A molecular modeling approach was used to elucidate template-monomer interaction and the effect of solvent on the recognition of molecularly imprinted polymers （MIPs）. Ciprofloxacin （CIP） was taken as the template molecule. The methacrylic acid （MAA）, 4-vinyl pyridine （4-Vpy）, acrylamide （AAM）, and 2-（trifluoromethyl） acrylic acid （TFMAA） were taken as the functional monomers, respectively. Density functional theory （DFT） at the LC-WPBE/6-31g（d,p） level has been adopted to investigate the geometry optimization. The NBO charge and the binding energies of CIP with the monomers were carried out. The molecular imprinting mechanism of CIP and the monomers as well as the influence of solvent was also discussed. Results indicate that CIP and the monomers are matchable in steric structure and chemical groups lead to ordered compounds. The interaction between CIP and TFMAA is the strongest, and when the ratio of CIP-TFMA_A is 1：6, the polymer has the lowest energy in toluene. The computational approach has been applied to provide details of interactions between CIP and the monomers. This research will hopefully shed light on the future study of CIP-MIPs.

Quantum Chemistry Investigation into the Distribution Properties of 2-Formamido-phenylacrylates in n-Octanol/Water System

Molecular property parameters of 16 2-formamido-phenylacryiates were calculated with Hartree-Fock and DFT methods at six different levels. Using the molecular property parameters and dissolvability as theoretical descriptors, two quantitative correlation equations that could be used to predict lgKow were developed based on experimental lgKow data of 11 2-formamido-phenylacrylates. A three-parameter correlation equation posing the ability of predicting -lgSw value was computed at B3LYP/6-311G＊＊ level. The -lgSw values of five compounds that we have pre-designed were anticipated with the above equation, upon which lgKow were further calculated. The relativity （r^2≥0.94, q^2〉0.91, SD≤0.083） and prediction ability of obtained correlation equations in this work are more advantageous than those based on solvatochromism parameters.

Study of Quantitative Structure-retention Relationship for Substituted Phenols

Quantum chemistry parameters of 20 substituted phenols were computed at the 6- 31G＊ level using DFT method. Based on theoretical linear solvation energy theory, the correlation equation that can predict the retention index （Ri） was developed using structural parameters of 15 substituted phenols with experimental data as theoretical descriptors, and the conventional correlation coefficient （R^2） is 0.9885. The correlation degree of each independent variable in the model was validated by variance inflation factors （VIF） and t-test. Cross-validation indicates that the model possesses high predicting ability. The correlation and predicting ability of the Ri equation are both more advantageous than those based on orientating group index, connectivity index, and topological index method. In addition, RI values of 5 compounds without experimental data were predicted with the model.

QSPR Study on Octanol/water Partition Coefficient (lgK_(ow)) of Substituted Naphthalin Compounds

Structural parameters of 24 substituted naphthalin compounds were computed at four levels using Hartree-Fock and DFT methods. Based on the experimental data of octanol/water partition coefficient （lgKow）, three-parameter （energy of the highest occupied molecular orbital （EHOMO）, the most positive, atomic net charges of molecule （q^＋） and molecular average polarizability （α）） dependent equations were developed using structural parameters as theoretical descriptors. Especially, lgKow dependent equation calculated at the HF/6-311G^＊＊ level is more advantageous than others in view of their correlation and predictive abilities. This dependent equation was validated by variance inflation factors （VIF） and t-test methods and used to predict lgKow of eight designed compounds. Upon comparison, the predictive abilities of our work are all more advantageous than those calculated from molecular property calculator program.

Correlation of Quantitative Structure and Inhibition Phytotoxicity for Aromatic Compounds Using Ab Initio Method

29 aromatic compounds were computed at the HF/6-31G^＊ level. Based on linear solvation energy theory firstly, the parameters of molecular structure were taken as theoretical descriptors, and the corresponding linear solvation energy relationship （LSER） （r^2= 0.8993, q^2=0.8559） between the structural parameters and inhibition phytotoxicity to the seed germination rate of cucumis （-lgGC50） was thus obtained. Then the parameters of molecular structure and thermodynamics were taken as theoretical descriptors, and as a result the other corresponding correlation equation （r^2=0.9268, q^2=0.8960） relating to -lgGC50 was achieved. The two equations obtained in this work by HF/6-31G^＊ are both more advantageous than that from AM 1.

Studies on the Quantitative Structure-activity Relationship of Substituted Biphenyls by Density Function Theory (DFT)

Geometrical configurations of 16 substituted biphenyls were computed at the B3LYP/6-311G^＊＊ level with Gaussian 98 program. Based on linear solvation energy theory, lgKow as well as the structural and thermodynamic parameters obtained at this level was taken as theoretical descriptors, and corresponding equation predicting the toxicity of Daphnia magna （-lgEC5o） was thus obtained, in which three parameters were contained, i.e., n-octanol/water partition coefficients （lgKow）, dipole moment of the molecules（ μ） and entropy （S°）. For this equation, R^2 = 0.9582, q^2 = 0.8921 and SD = 0.102. The absolute t-scores of three variables are larger than the standard one in the confidence range of 95%, which confirms the creditability and stability of this model.

Mechanism analysis of ions interaction in MgCl_2/LiCl solution and effect of lithium on ammonia precipitation products

Producing magnesium hydroxide is the basic way to utilize magnesium resources of natural brines. However, the effect of lithium on properties of product is always neglected. The interaction between ions in magnesium chloride solution containing lithium was illustrated based on the experimental results, and the effect of lithium on the crystallization of magnesium was clarified. The results of X-ray diffraction（XRD）, scanning election microscope（SEM）, Fourier transform infrared spectroscopy（FTIR）, thermogravimetry analysis（TGA） and laser particle size analysis indicate that the effect of lithium is not obvious on the crystal phase and morphology of the products. But the XRD relative intensity of（001） surface of magnesium hydroxide declines, the specific surface area reduces apparently and the additive mass of lithium affects the heat loss rates of precipitations obviously. Quantum chemical calculations on the interactional systems of Mg（H2O）2＋6 and Li（H2O）＋4 were performed using B3LYP/6-311 G basis set. The results show that when the distance of Mg2＋ and Li＋ is 7-10 , the interaction energy is high and the trend of solvation is strong, which would make hydroxide ions easier to combine with hydrogen ions in ammonia precipitation process. And the absolute value of solvation free energy reduces significantly in MgCl2 solution（1 mol/L） containing lithium ion.

Theoretical insights on the hydration of quinones as catholytes in aqueous redox flow batteries

Quinones have been widely studied as a potential catholyte in water-based redox flow batteries(RFBs)due to their ability to carry both electrons and protons in aqueous solutions.The wide variety of quinones and derivatives offers exciting opportunities to optimize the device performance while poses theoretical challenges to quantify their electrochemical behavior as required for molecular design.Computational screening of target quinones with high performance is far from satisfactory.While solvation of quinones affects their potential application in RFBs in terms of both electrochemical windows,stability,and charge transport,experimental data for the solvation structure and solvation free energies are rarely available if not incomplete.Besides,conventional thermodynamic models are mostly unreliable to estimate the properties of direct interest for electrochemical applications.Here,we analyze the hydration free energies of more than 1,400 quinones by combining the first-principles calculations and the classical density functional theory.In order to attain chemical insights and possible trends,special attention is placed on the effects of"backbones"and functional groups on the solvation behavior.The theoretical results provide a thermodynamic basis for the design,synthesis,and screening of high-performance catholytes for electrical energy storage.

HRW:Hybrid Residual and Weak Form Loss for Solving Elliptic Interface Problems with Neural Network

Deep learning techniques for solving elliptic interface problems have gained significant attentions.In this paper,we introduce a hybrid residual and weak form(HRW)loss aimed at mitigating the challenge of model training.HRW utilizes the functions residual loss and Ritz method in an adversary-system,which enhances the probability of jumping out of the local optimum even when the loss landscape comprises multiple soft constraints(regularization terms),thus improving model’s capability and robustness.For the problem with interface conditions,unlike existing methods that use the domain decomposition,we design a Pre-activated ResNet of ResNet(PRoR)network structure employing a single network to feed both coordinates and corresponding subdomain indicators,thus reduces the number of parameters.The effectiveness and improvements of the PRoR with HRW are verified on two-dimensional interface problems with regular or irregular interfaces.We then apply the PRoR with HRW to solve the size-modified Poisson-Boltzmann equation,an improved dielectric continuum model for predicting the electrostatic potentials in an ionic solvent by considering the steric effects.Our findings demonstrate that the PRoR with HRW accurately approximates solvation free-energies of three proteins with irregular interfaces,showing the competitive results compared to the ones obtained using the finite element method.

Identifying potential compounds from Bacopa monnieri(brahmi)against coxsackievirus A16 RdRp targeting HFM disease(tomato flu)

Hand,foot,and mouth disease(HFMD),primarily instigated by Coxsackievirus A16(CVA16),poses a serious health concern,necessitating effective therapeutic interventions.The RNA-dependent RNA polymerase(RdRp)of CVA16 emerges as a promising drug target for HFMD treatment.This study presents an in-silico pipeline for the identification of potential RdRp inhibitors against CVA16.A library of 91 natural compounds derived from Bacopa monnieri(brahmi)was virtually screened against the CVA16 RdRp.Here,Bacobitacin D emerged as a promising hit molecule,forming 8 hydrogen bonds including key catalytic site residues(Asp^(238)and Asp^(329))within the RdRp active site.Further,molecular dynamics(MD)simulations and MM/GBSA binding free energy calculations was applied on the top three hits that were selected based on exhaustive docking scores(≤-9.55 kcal/mol).Bacobitacin D exhibited sustainable stability,as evidenced by minimal deviation(RMSD=0.75±0.02 nm)during a 100 ns MD simulation.Importantly,Bacopaside IV exhibited the lowestΔGTOTAL binding free energy(-23.70 kcal/mol),while Bacobitacin D displayed a comparableΔGTOTAL of19.14 kcal/mol.Structural interpretation of the most populated cluster derived from MD simulations showed direct interactions of Bacobitacin D with pivotal catalytic residues,including Asp^(238)and Ser^(289).This comprehensive study confirmed Bacobitacin D as a potent inhibitor of CVA16 RdRp,offering a potential avenue for therapeutic intervention against HFMD.Experimental validation is required to confirm the inhibitory action of Bacobitacin D against HFMD.