Artemisinins tested against W-2 strains of malaria falciparum are investigated with molecular electrostatic potential (MEP), in an attempt to identify key features of the compounds that are necessary for their activit...Artemisinins tested against W-2 strains of malaria falciparum are investigated with molecular electrostatic potential (MEP), in an attempt to identify key features of the compounds that are necessary for their activities, as well as to investigate likely interactions with the receptor in a biological process and to use that information to propose new molecules. In order to discover the best geometry involving the ligand-receptor complexes (heme) studied and help in the proposition of the new derivatives, molecular simulations of interactions between the most negative charged region around the peroxide and heme locates (the ones around the Fe2+ ion) were carried out. In addition, PCA (principal components analysis), HCA (hierarchical cluster analysis), SDA (stepwise discriminant analysis), and KNN (K-nearest neighbor) multivariate models were employed to investigate which descriptors are responsible for the classification between the higher and lower antimalarial activity of the compounds, and also this information was used to propose new potentially active molecules. The information accumulated in studies of MEP, molecular docking, and multivariate analysis supported the proposal of new structures with potential antimalarial activities. The multivariate models constructed were applied to the new structures and indicated numbers 19 and 20 as the most prominent for syntheses and biological assays.展开更多
Revealing the charge generation is a crucial step to understand the organic photovoltaics. Recent development in non-fullerene organic solar cells (OSCs) indicates efficient charge separation even with negligible en...Revealing the charge generation is a crucial step to understand the organic photovoltaics. Recent development in non-fullerene organic solar cells (OSCs) indicates efficient charge separation even with negligible energetic offset between the donor and acceptor materials. These new findings trigger a critical question concerning the charge separation mechanism in OSCs, traditionally believed to result from sufficient energetic offset between the polymer donor and fullerene acceptor. We propose a new mechanism, which involves the molecular electrostatic potential, to explain efficient charge separation in non-fullerene OSCs. Together with the new mechanism, we demonstrate a record efficiency of -12% for systems with negligible energetic offset between donor and acceptor materials. Our analysis also rationalizes different requirement of the energetic offset between fullerene-based and non-fullerene OSCs, and paves the way for further design of OSC materials with both high photocurrent and high photovottage at the same time.展开更多
In the present study,geometrical optimization and electrostatic potential calcula-tions have been performed for 22 nitroaromatic compounds at the HF/6-31G level of theory.A number of statistically based parameters hav...In the present study,geometrical optimization and electrostatic potential calcula-tions have been performed for 22 nitroaromatic compounds at the HF/6-31G level of theory.A number of statistically based parameters have been obtained.Linear relationship between the decomposition enthalpy(taken as a macroscopic property related to explosibility) of nitroaromatic compounds and the structural descriptors have been established by multiple regression method.The result shows that the quantities derived from electrostatic potentialsΣ V sind+,,Vsind- and Vs,max can be well used to express the quantitative structure-decomposition enthalpy relationship of nitroa-romatic compounds,which proves the general applicability of this parameter set to a great extent.Good predictive capabilities have also been demonstrated.展开更多
Based on the relationship between the quantitative structure and property(QSPR) of organic compounds, the surface electrostatic potential parameters of 29 polychlorinated diphenyl sulfides(PCDPSs) with experimenta...Based on the relationship between the quantitative structure and property(QSPR) of organic compounds, the surface electrostatic potential parameters of 29 polychlorinated diphenyl sulfides(PCDPSs) with experimental values were calculated and extracted, and Multiple Linear Regression(MLR) was used to model the linear relationship between the physicochemical properties(octanol/water partition coefficient, high performance liquid chromatography capacity factor) and molecular structure parameters of PCDPSs. The result shows that the main factors that affect the n-octanol/water partition coefficient and high performance liquid chromatography capacity factor are respectively the number of chlorin atoms substituted on the benzene ring(NCl) and the lowest unoccupied molecular orbital energy(ELUMO). Secondly, there are also molecular surface electrostatic potentials. This indicates that the molecular surface electrostatic potentials can effectively express the quantitative relationship between the physicochemical properties of PCDPSs and their molecule descriptions. The QSPR models established have strong stability and predictive ability. This also has proved the applicability of molecular surface electrostatic potential parameters in QSPR of PCDPSs.展开更多
Polychlorinated dibenzo-p-dioxins(PCDDs) are a group of important persistent organic pollutants.They are highly toxic and persistent in environment.In the present study,geometrical optimization and electrostatic pot...Polychlorinated dibenzo-p-dioxins(PCDDs) are a group of important persistent organic pollutants.They are highly toxic and persistent in environment.In the present study,geometrical optimization and electrostatic potential calculations have been performed for 75 PCDD congeners and dibenzo-p-dioxin(DD) at the HF/6-31G* level of theory.A number of statistically based parameters have been extracted.Linear relationships between vapor pressures(logpL),aqueous solubilities(logSw),n-octanol/water partition coefficients(logKow) of PCDDs and structural descriptors have been established by stepwise linear regression analysis.The result shows that the quantities derived from the surface electrostatic potentials Vmin,Π,and Vs,av+,together with Vmc(the molecular volume) and ELUMO(the energy of the lowest unoccupied molecular orbital) can be well used to express the quantitative structure-property relationships of PCDDs.Predictive capabilities of the models have also been demonstrated by leave-one-out cross-validation with the cross-validated correlation coefficient(Rcv) above 0.97.Based on these QSPR models,the predicted values have been presented for those PCDD congeners whose experimentally determined physicochemical properties are unavailable.展开更多
A method has been developed for separation of 20 kinds of aromatic carboxylic acid using anion-exchange chromatography. A Dionex IonPac AS9-HC guard column (250mm×2mm) was used with a 9mmol/L sodium carbonate s...A method has been developed for separation of 20 kinds of aromatic carboxylic acid using anion-exchange chromatography. A Dionex IonPac AS9-HC guard column (250mm×2mm) was used with a 9mmol/L sodium carbonate solution containing 50% (v/v) acetonitrile as eluent. A set of retention time data has been obtained using a conductivity detector DS6. Furthermore, geometrical optimization and electrostatic potential calculation of 20 kinds of aromatic carboxylic acid have been performed at the HF/6-31G* level of theory. A number of statistically-based parameters derived from molecular surface electrostatic potential have been obtained. Linear relationship between retention time and structural parameters has been established by multiple regression method. The result shows that parameters derived from electrostatic potential Vs +, Vs -, П together with the dipole moment μ can be well used to express the quantitative structure-retention time of this kind of aromatic carboxylic acid. Good predictive capability has also been demonstrated. The result has provided a framework which further proves the general applicability of this electrostatic potential parameter set to a great extent,and with which the ion chromatographic adsorption mechanism can be investigated.展开更多
Polychlorinated dibenzofurans (PCDFs) represent an important kind of serious pollutant. They are highly toxic and persistent in environment. In this paper, geometrical optimizations and subsequent calculations o...Polychlorinated dibenzofurans (PCDFs) represent an important kind of serious pollutant. They are highly toxic and persistent in environment. In this paper, geometrical optimizations and subsequent calculations of electrostatic potentials (ESPs) on molecular surface have been performed for all 135 PCDF congeners at the HF/6-31G* level. The effects of substitution value and variation of substitution position upon the surface ESPs have been discussed. A series of statistic-based structural descriptors derived from the surface ESPs have been calculated. For some PCDF congeners, linear relationships between aryl hydrocarbon receptor (AhR) biding affinity and aryl hydrocarbon hydroxylase (AHH) induction potency as well as theoretical descriptors have been established by multiple linear regression method. It appears that the quantities derived from the surface ESPs, Vs,min, Vs , VS +, σ+ and Nvmin, 2 together with the molecular surface area and the energy gap between HOMO and LUMO can be well used to express the quantitative structure-toxicity relationships of PCDFs.展开更多
Halogenated methyl-phenyl ethers (anisoles) are ubiquitous organic compounds in the environment. In the present study, geometrical optimization and electrostatic potential calculations have been performed for 42 hal...Halogenated methyl-phenyl ethers (anisoles) are ubiquitous organic compounds in the environment. In the present study, geometrical optimization and electrostatic potential calculations have been performed for 42 halogenated anisoles at the HF/6-31 G^* level. A number of statistically based parameters have been obtained. By multiple regression method, linear relationships between the gas-chromatographic relative retention time (RRT) and structural descriptors have been established for the training set of 32 halogenated anisoles. The result showed that the parameters derived from electrostatic potentials (ESPs) together with the molecular volume (Vmc) could be well used to express the quantitative structure-RRT relationships of halogenated anisoles. The best two-variable regression model gives a correlation coefficient of 0.980 and a standard deviation of 0.07, and the leave-one-out cross-validated correlation coefficient is 0.975. The goodness of the model has been further validated through exploring the predictive power for the testing set of 10 halogenated anisoles.展开更多
Geometrical optimization and electrostatic potential calculations have been performed for a series of halogenated hydrocarbons at the HF/Gen-6d level. A number of electrostatic potentials and the statistically based s...Geometrical optimization and electrostatic potential calculations have been performed for a series of halogenated hydrocarbons at the HF/Gen-6d level. A number of electrostatic potentials and the statistically based structural descriptors derived from these electrostatic potentials have been obtained. Multiple linear regression analysis and artificial neural network are employed simultaneously in this paper. The result shows that the parameters derived from electrostatic 2 potentials σtot^2, V s and ∑ Vs^+, together with the molecular volume (Vine) can be used to express the quantitative structure-infinite dilution activity coefficients (γ^∞) relationship of halogenated hydrocarbons in water. The result also demonstrates that the model obtained by using BFGS quasiNewton neural network method has much better predictive capability than that from multiple linear regression. The goodness of the model has been validated through exploring the predictive power for the external test set. The model obtained via neural network may be applied to predict γ^∞ of other halogenated hydrocarbons not present in the data set.展开更多
Based on QSPR of alcohol and ether organic compounds in water,geometrical optimization and electrostatic potential calculations were performed at the HF/6-31G* level for 73 alcohol and ether organic compounds.Linear ...Based on QSPR of alcohol and ether organic compounds in water,geometrical optimization and electrostatic potential calculations were performed at the HF/6-31G* level for 73 alcohol and ether organic compounds.Linear relationships between infinite dilution activity coef-ficient(lnγ∞) of alcohols and ethers in water and theoretical descriptors of the molecular structure were established by multiple regression method.The result shows that the parameters derived from molecular electrostatic potential together with molecular surface area can be preferably used to express the quantitative structure-lnγ∞ relationship of alcohols and ethers in water.This reveals that this model has good predictive capabilities(RCV=0.969).The molecular electrostatic potential has also been proved to have the general applicability in QSPR model of alcohol and ether organic compounds about γ∞ in water.The QSPR model established may provide a new powerful method for predicting γ∞ of organic compounds in aqueous systems.展开更多
The fabrication of multifunctional electronic devices based on the intriguing natures of organic semiconductors is crucial for organic electronics.Ultranarrow-bandgap materials are in urgent demand for fabricating hig...The fabrication of multifunctional electronic devices based on the intriguing natures of organic semiconductors is crucial for organic electronics.Ultranarrow-bandgap materials are in urgent demand for fabricating high-performance organic photovoltaic(OPV)cells and highly sensitive near-infrared organic photodetectors(OPDs).By combining alkoxy modification and an asymmetric strategy,three narrowbandgap electronic acceptors(BTP-4F,DO-4F,and QO-4F)were synthesized with finely tuned molecular electrostatic potential(ESP)distributions.Through the careful modulation of electronic configurations,the optical absorption onsets of DO-4F and QO-4F exceeded 1μm.The experimental and theoretical results suggest that the small ESP of QO-4F is beneficial for achieving a low nonradiative voltage loss,while the large ESP of BTP-4F can help obtain high exciton dissociation efficiency.By contrast,the asymmetric acceptor DO-4F with a moderate ESP possesses balanced voltage loss and exciton dissociation,yielding the best power conversion efficiency of 13.6%in the OPV cells.OPDs were also fabricated based on the combination of PBDB-T:DO-4F,and the as-fabricated device outputs a high shot-noise-limited specific detectivity of 3.05×10^(13) Jones at 850 nm,which is a very good result for near-infrared OPDs.This work is anticipated to provide a rational way of designing high-performance ultranarrow-bandgap organic semiconductors by modulating the molecular ESP.展开更多
In this work, we theoretically probe into the photo-induced hydrogen bonding effects between S0 state and S1 state as well as the excited state intramolecular proton transfer(ESIPT) behavior for a novel 2-[1,3]dithian...In this work, we theoretically probe into the photo-induced hydrogen bonding effects between S0 state and S1 state as well as the excited state intramolecular proton transfer(ESIPT) behavior for a novel 2-[1,3]dithian-2-yl-6-(7aH-indol-2-yl)-phenol(DIP) probe system. We first study the ground-state hydrogen bonding O–H··· N behavior for DIP. Then we analyze the primary geometrical parameters(i.e., bond length, bond angle, and infrared(IR) stretching vibrational mode)involved in hydrogen bond, and confirm that the O–H··· N of DIP should be strengthened in the first excited state. It is the significant prerequisite for ESIPT reaction. Combining the frontier molecular orbitals(MOs) with vertical excitation analyses, the intramolecular charge transfer(ICT) phenomenon can be found for the DIP system, which reveals that the charge redistribution facilitates ESIPT behavior. By constructing potential energy curves for DIP along the ESIPT reactional orientation, we obtain quite a small energy barrier(3.33 kcal/mol) and affirmed that the DIP molecule undergoes ultrafast ESIPT process once it is excited to the S1 state and quickly transfers its proton, forming DIP-keto tautomer. That is why no fluorescence of DIP can be observed in experiment, which further reveals the ultrafast ESIPT mechanism proposed in this work.展开更多
The isomeric structures of(E)-1-[4-(2-hydroxy-5-methoxybenzylideneamino)-phenyl] ethanone(I) and(E)-1-[4-(2-hydroxy-4-methoxybenzylideneamino) phenyl]ethanone(Ⅱ) ,both C16H15NO3,have been determined using...The isomeric structures of(E)-1-[4-(2-hydroxy-5-methoxybenzylideneamino)-phenyl] ethanone(I) and(E)-1-[4-(2-hydroxy-4-methoxybenzylideneamino) phenyl]ethanone(Ⅱ) ,both C16H15NO3,have been determined using X-ray diffraction techniques and characterized by IR,and their molecular structures have also been optimized at the B3LYP/6-31G(d,p) level using density functional theory(DFT) . The energetic behaviors of the title compounds in solvent media have been examined using B3LYP method with the 6-31G(d,p) basis set by applying the polarizable continuum model(PCM) . The total energies of the title compounds decrease with the increasing polarity of the solvent. In addition,DFT calculations of the title compounds' molecular electrostatic potentials(MEP) were performed at the B3LYP/6-31G(d,p) level of theory. X-ray study shows that the title compounds both have strong intramolecular O-H…N hydrogen bonds. The molecules of Ⅰ are linked into a one-dimensional framework structure by C-H…π interactions,while in Ⅱ,intermolecular π···π interactions result in the formation of infinite chains running along the [010].展开更多
Chloronaphthalenes (PCNs, polychlorinated naphthalenes) are a group of persistent environmental pollutants. In the present study, geometrical optimization and electrostatic potential calculations have been performed...Chloronaphthalenes (PCNs, polychlorinated naphthalenes) are a group of persistent environmental pollutants. In the present study, geometrical optimization and electrostatic potential calculations have been performed for all 75 PCNs at the HF/6-31G^* level of theory. A number of statistic based parameters have been extracted. Linear relationships between gas-chromatographic retention index (RI) of 62 PCNs in a non-polar column (DB-5) and the structural descriptors have been established by stepwise multiple regression technique. The result shows that two quantities derived from electrostatic potential on molecular surface, ∑Vs- and σ+^2, together with the number of chlorine ( NCl ) and the energy of the highest occupied molecular orbital (EHOMO) can be well used to express the quantitative structure-retention relationship (QSRR) of PCNs. Predictive capability of the model has been demonstrated by leave-one-out cross-validation with the cross-validated correlation coefficient (Rcv^2) of 0.997, and further compared with the results from similar researches published recently. Furthermore, when splitting the 62 PCNs into training and validation sets in the ratio of 2:1, a similar treatment yields an equation of almost equal statistical quality and very similar regression coefficients, validating the robustness and prediction capability of our model. The QSRR model established may provide a new powerful method for predicting chromatographic properties of polychlorinated naphthalenes.展开更多
In this research, the hydrogen bonds Y···H-X (X = C, N; Y = N, O) of thymine and uracil have been theoretically studied. The results show that hydrogen bond leads to bond length elongation and stretch...In this research, the hydrogen bonds Y···H-X (X = C, N; Y = N, O) of thymine and uracil have been theoretically studied. The results show that hydrogen bond leads to bond length elongation and stretches the frequency red-shift of N-H···Y. Meanwhile, the C-H···O bonds shorten and stretch the frequency blue-shift. They all belong to traditional hydrogen bonds. The intermolecular charge transfer caused by the intermolecular hyperconjugation s*(N–H) → n(Y) and intramolecular charge redistribution by intramolecular hyperconjugation σ(C-H) →σ*(C-N) play important roles in the formation of hydrogen bonds. According to thejudgment standards proposed by Bader and Popelier, these hydrogen bonds have typical electron density topological properties. Electrostatic surface potential (ESP) is a useful physicochemical property of a molecule that provides insights into inter- and intramolecular associations, as well as the prediction of likely sites of electrophilic and nucleophilic metabolic attack.展开更多
Rhein(Rhe), an anthraquinone derivative, exhibits excellent anti-inflammatory effects and other pharmacological activities, but its clinical application remains limited due to poor solubility. The present work aims at...Rhein(Rhe), an anthraquinone derivative, exhibits excellent anti-inflammatory effects and other pharmacological activities, but its clinical application remains limited due to poor solubility. The present work aims at the improvement of solubility and oral bioavailability of Rhe through cocrystal formation. For this purpose, Rhe and matrine(Mat) were selected as pharmaceutical ingredient(API) and cocrystal former(CCF), respectively, and the Rhe-Mat cocrystal was synthesized and characterized by single crystal X-ray diffraction(SXRD), powder X-ray diffraction(PXRD), thermogravimetric analysis(TGA), differential scanning calorimetry(DSC). The formation mechanism of Rhe-Mat cocrystal was elucidated by molecular surface electrostatic potential(MSEP). It is worth mentioning that the 50-fold increment of dissolution in vitro was observed in pure water in the form of Rhe-Mat cocrystal. Furthermore, the in vivo studies revealed that Rhe-Mat cocrystal indicated the faster absorption rate and the higher peak blood concentration than the pure Rhe. Hence, it can be concluded that current study successfully improved the solubility and oral bioavailability of Rhe.展开更多
文摘Artemisinins tested against W-2 strains of malaria falciparum are investigated with molecular electrostatic potential (MEP), in an attempt to identify key features of the compounds that are necessary for their activities, as well as to investigate likely interactions with the receptor in a biological process and to use that information to propose new molecules. In order to discover the best geometry involving the ligand-receptor complexes (heme) studied and help in the proposition of the new derivatives, molecular simulations of interactions between the most negative charged region around the peroxide and heme locates (the ones around the Fe2+ ion) were carried out. In addition, PCA (principal components analysis), HCA (hierarchical cluster analysis), SDA (stepwise discriminant analysis), and KNN (K-nearest neighbor) multivariate models were employed to investigate which descriptors are responsible for the classification between the higher and lower antimalarial activity of the compounds, and also this information was used to propose new potentially active molecules. The information accumulated in studies of MEP, molecular docking, and multivariate analysis supported the proposal of new structures with potential antimalarial activities. The multivariate models constructed were applied to the new structures and indicated numbers 19 and 20 as the most prominent for syntheses and biological assays.
基金J. Hou acknowledge financial support from National Natural Science Foundation of China (91633301, 51673201, 91333204), the Ministry of Science and Technology of China (2014CB643501) and the Chinese Academy of Sciences (XDB12030200). F. Gao and D. Qian would like to acknowledge the Swedish Research Council VR (Grant No. 2017-007444 the Swedish Energy Agency Ener- gimyndigheten (2016-010174), the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant No. SFO-Mat-LiU #2009- 00971).
文摘Revealing the charge generation is a crucial step to understand the organic photovoltaics. Recent development in non-fullerene organic solar cells (OSCs) indicates efficient charge separation even with negligible energetic offset between the donor and acceptor materials. These new findings trigger a critical question concerning the charge separation mechanism in OSCs, traditionally believed to result from sufficient energetic offset between the polymer donor and fullerene acceptor. We propose a new mechanism, which involves the molecular electrostatic potential, to explain efficient charge separation in non-fullerene OSCs. Together with the new mechanism, we demonstrate a record efficiency of -12% for systems with negligible energetic offset between donor and acceptor materials. Our analysis also rationalizes different requirement of the energetic offset between fullerene-based and non-fullerene OSCs, and paves the way for further design of OSC materials with both high photocurrent and high photovottage at the same time.
基金Supported by the National Natural Science Foundation of China(No.20502022)the Natural Science Foundation of Ningbo (No.2004A610010)
文摘In the present study,geometrical optimization and electrostatic potential calcula-tions have been performed for 22 nitroaromatic compounds at the HF/6-31G level of theory.A number of statistically based parameters have been obtained.Linear relationship between the decomposition enthalpy(taken as a macroscopic property related to explosibility) of nitroaromatic compounds and the structural descriptors have been established by multiple regression method.The result shows that the quantities derived from electrostatic potentialsΣ V sind+,,Vsind- and Vs,max can be well used to express the quantitative structure-decomposition enthalpy relationship of nitroa-romatic compounds,which proves the general applicability of this parameter set to a great extent.Good predictive capabilities have also been demonstrated.
基金Supported by the Natural Science Foundation of Zhejiang Province(LY12B07013)the Education Research Project of Zhejiang Provincial Department(Y201329851)
文摘Based on the relationship between the quantitative structure and property(QSPR) of organic compounds, the surface electrostatic potential parameters of 29 polychlorinated diphenyl sulfides(PCDPSs) with experimental values were calculated and extracted, and Multiple Linear Regression(MLR) was used to model the linear relationship between the physicochemical properties(octanol/water partition coefficient, high performance liquid chromatography capacity factor) and molecular structure parameters of PCDPSs. The result shows that the main factors that affect the n-octanol/water partition coefficient and high performance liquid chromatography capacity factor are respectively the number of chlorin atoms substituted on the benzene ring(NCl) and the lowest unoccupied molecular orbital energy(ELUMO). Secondly, there are also molecular surface electrostatic potentials. This indicates that the molecular surface electrostatic potentials can effectively express the quantitative relationship between the physicochemical properties of PCDPSs and their molecule descriptions. The QSPR models established have strong stability and predictive ability. This also has proved the applicability of molecular surface electrostatic potential parameters in QSPR of PCDPSs.
基金supported by the Analysis and Measurement Planning Project of Zhejiang Province (2007F70053)
文摘Polychlorinated dibenzo-p-dioxins(PCDDs) are a group of important persistent organic pollutants.They are highly toxic and persistent in environment.In the present study,geometrical optimization and electrostatic potential calculations have been performed for 75 PCDD congeners and dibenzo-p-dioxin(DD) at the HF/6-31G* level of theory.A number of statistically based parameters have been extracted.Linear relationships between vapor pressures(logpL),aqueous solubilities(logSw),n-octanol/water partition coefficients(logKow) of PCDDs and structural descriptors have been established by stepwise linear regression analysis.The result shows that the quantities derived from the surface electrostatic potentials Vmin,Π,and Vs,av+,together with Vmc(the molecular volume) and ELUMO(the energy of the lowest unoccupied molecular orbital) can be well used to express the quantitative structure-property relationships of PCDDs.Predictive capabilities of the models have also been demonstrated by leave-one-out cross-validation with the cross-validated correlation coefficient(Rcv) above 0.97.Based on these QSPR models,the predicted values have been presented for those PCDD congeners whose experimentally determined physicochemical properties are unavailable.
基金Supported by the Project of Analysis and Detection of Zhejiang Province in 2009 (No. 2009F7044)
文摘A method has been developed for separation of 20 kinds of aromatic carboxylic acid using anion-exchange chromatography. A Dionex IonPac AS9-HC guard column (250mm×2mm) was used with a 9mmol/L sodium carbonate solution containing 50% (v/v) acetonitrile as eluent. A set of retention time data has been obtained using a conductivity detector DS6. Furthermore, geometrical optimization and electrostatic potential calculation of 20 kinds of aromatic carboxylic acid have been performed at the HF/6-31G* level of theory. A number of statistically-based parameters derived from molecular surface electrostatic potential have been obtained. Linear relationship between retention time and structural parameters has been established by multiple regression method. The result shows that parameters derived from electrostatic potential Vs +, Vs -, П together with the dipole moment μ can be well used to express the quantitative structure-retention time of this kind of aromatic carboxylic acid. Good predictive capability has also been demonstrated. The result has provided a framework which further proves the general applicability of this electrostatic potential parameter set to a great extent,and with which the ion chromatographic adsorption mechanism can be investigated.
基金Supported by the Ph.D. Fund of Ningbo (No. 2004A610010)
文摘Polychlorinated dibenzofurans (PCDFs) represent an important kind of serious pollutant. They are highly toxic and persistent in environment. In this paper, geometrical optimizations and subsequent calculations of electrostatic potentials (ESPs) on molecular surface have been performed for all 135 PCDF congeners at the HF/6-31G* level. The effects of substitution value and variation of substitution position upon the surface ESPs have been discussed. A series of statistic-based structural descriptors derived from the surface ESPs have been calculated. For some PCDF congeners, linear relationships between aryl hydrocarbon receptor (AhR) biding affinity and aryl hydrocarbon hydroxylase (AHH) induction potency as well as theoretical descriptors have been established by multiple linear regression method. It appears that the quantities derived from the surface ESPs, Vs,min, Vs , VS +, σ+ and Nvmin, 2 together with the molecular surface area and the energy gap between HOMO and LUMO can be well used to express the quantitative structure-toxicity relationships of PCDFs.
基金This work was supported by the National Natural Science Foundation of China (No. 20502022) and the Ph.D. Fund of Ningbo ( No. 2004A610010)
文摘Halogenated methyl-phenyl ethers (anisoles) are ubiquitous organic compounds in the environment. In the present study, geometrical optimization and electrostatic potential calculations have been performed for 42 halogenated anisoles at the HF/6-31 G^* level. A number of statistically based parameters have been obtained. By multiple regression method, linear relationships between the gas-chromatographic relative retention time (RRT) and structural descriptors have been established for the training set of 32 halogenated anisoles. The result showed that the parameters derived from electrostatic potentials (ESPs) together with the molecular volume (Vmc) could be well used to express the quantitative structure-RRT relationships of halogenated anisoles. The best two-variable regression model gives a correlation coefficient of 0.980 and a standard deviation of 0.07, and the leave-one-out cross-validated correlation coefficient is 0.975. The goodness of the model has been further validated through exploring the predictive power for the testing set of 10 halogenated anisoles.
文摘Geometrical optimization and electrostatic potential calculations have been performed for a series of halogenated hydrocarbons at the HF/Gen-6d level. A number of electrostatic potentials and the statistically based structural descriptors derived from these electrostatic potentials have been obtained. Multiple linear regression analysis and artificial neural network are employed simultaneously in this paper. The result shows that the parameters derived from electrostatic 2 potentials σtot^2, V s and ∑ Vs^+, together with the molecular volume (Vine) can be used to express the quantitative structure-infinite dilution activity coefficients (γ^∞) relationship of halogenated hydrocarbons in water. The result also demonstrates that the model obtained by using BFGS quasiNewton neural network method has much better predictive capability than that from multiple linear regression. The goodness of the model has been validated through exploring the predictive power for the external test set. The model obtained via neural network may be applied to predict γ^∞ of other halogenated hydrocarbons not present in the data set.
文摘Based on QSPR of alcohol and ether organic compounds in water,geometrical optimization and electrostatic potential calculations were performed at the HF/6-31G* level for 73 alcohol and ether organic compounds.Linear relationships between infinite dilution activity coef-ficient(lnγ∞) of alcohols and ethers in water and theoretical descriptors of the molecular structure were established by multiple regression method.The result shows that the parameters derived from molecular electrostatic potential together with molecular surface area can be preferably used to express the quantitative structure-lnγ∞ relationship of alcohols and ethers in water.This reveals that this model has good predictive capabilities(RCV=0.969).The molecular electrostatic potential has also been proved to have the general applicability in QSPR model of alcohol and ether organic compounds about γ∞ in water.The QSPR model established may provide a new powerful method for predicting γ∞ of organic compounds in aqueous systems.
基金the support from the National Natural Science Foundation of China(NSFC,21835006)the financial support from the NSFC(22075301 and 22122905)+2 种基金the Youth Innovation Promotion Association CAS(2018043)the Key Research Program of the Chinese Academy of Sciences,Grant NO.XDPB13-3supported by the Beijing National Laboratory for Molecular Sciences(BNLMS-CXXM-201903)。
文摘The fabrication of multifunctional electronic devices based on the intriguing natures of organic semiconductors is crucial for organic electronics.Ultranarrow-bandgap materials are in urgent demand for fabricating high-performance organic photovoltaic(OPV)cells and highly sensitive near-infrared organic photodetectors(OPDs).By combining alkoxy modification and an asymmetric strategy,three narrowbandgap electronic acceptors(BTP-4F,DO-4F,and QO-4F)were synthesized with finely tuned molecular electrostatic potential(ESP)distributions.Through the careful modulation of electronic configurations,the optical absorption onsets of DO-4F and QO-4F exceeded 1μm.The experimental and theoretical results suggest that the small ESP of QO-4F is beneficial for achieving a low nonradiative voltage loss,while the large ESP of BTP-4F can help obtain high exciton dissociation efficiency.By contrast,the asymmetric acceptor DO-4F with a moderate ESP possesses balanced voltage loss and exciton dissociation,yielding the best power conversion efficiency of 13.6%in the OPV cells.OPDs were also fabricated based on the combination of PBDB-T:DO-4F,and the as-fabricated device outputs a high shot-noise-limited specific detectivity of 3.05×10^(13) Jones at 850 nm,which is a very good result for near-infrared OPDs.This work is anticipated to provide a rational way of designing high-performance ultranarrow-bandgap organic semiconductors by modulating the molecular ESP.
基金Project supported by the National Natural Science Foundation of China(Grant No.11574083).
文摘In this work, we theoretically probe into the photo-induced hydrogen bonding effects between S0 state and S1 state as well as the excited state intramolecular proton transfer(ESIPT) behavior for a novel 2-[1,3]dithian-2-yl-6-(7aH-indol-2-yl)-phenol(DIP) probe system. We first study the ground-state hydrogen bonding O–H··· N behavior for DIP. Then we analyze the primary geometrical parameters(i.e., bond length, bond angle, and infrared(IR) stretching vibrational mode)involved in hydrogen bond, and confirm that the O–H··· N of DIP should be strengthened in the first excited state. It is the significant prerequisite for ESIPT reaction. Combining the frontier molecular orbitals(MOs) with vertical excitation analyses, the intramolecular charge transfer(ICT) phenomenon can be found for the DIP system, which reveals that the charge redistribution facilitates ESIPT behavior. By constructing potential energy curves for DIP along the ESIPT reactional orientation, we obtain quite a small energy barrier(3.33 kcal/mol) and affirmed that the DIP molecule undergoes ultrafast ESIPT process once it is excited to the S1 state and quickly transfers its proton, forming DIP-keto tautomer. That is why no fluorescence of DIP can be observed in experiment, which further reveals the ultrafast ESIPT mechanism proposed in this work.
基金the Faculty of Arts and Sciences,Ondokuz Mayls University,Turkey,for the use of the Stoe IPDSII diffractometer (purchased under grant No. F279 of the University Research Fund)
文摘The isomeric structures of(E)-1-[4-(2-hydroxy-5-methoxybenzylideneamino)-phenyl] ethanone(I) and(E)-1-[4-(2-hydroxy-4-methoxybenzylideneamino) phenyl]ethanone(Ⅱ) ,both C16H15NO3,have been determined using X-ray diffraction techniques and characterized by IR,and their molecular structures have also been optimized at the B3LYP/6-31G(d,p) level using density functional theory(DFT) . The energetic behaviors of the title compounds in solvent media have been examined using B3LYP method with the 6-31G(d,p) basis set by applying the polarizable continuum model(PCM) . The total energies of the title compounds decrease with the increasing polarity of the solvent. In addition,DFT calculations of the title compounds' molecular electrostatic potentials(MEP) were performed at the B3LYP/6-31G(d,p) level of theory. X-ray study shows that the title compounds both have strong intramolecular O-H…N hydrogen bonds. The molecules of Ⅰ are linked into a one-dimensional framework structure by C-H…π interactions,while in Ⅱ,intermolecular π···π interactions result in the formation of infinite chains running along the [010].
基金Supported by the Analysis and Measurement Planning Project of Zhejiang Province (2007F70053)
文摘Chloronaphthalenes (PCNs, polychlorinated naphthalenes) are a group of persistent environmental pollutants. In the present study, geometrical optimization and electrostatic potential calculations have been performed for all 75 PCNs at the HF/6-31G^* level of theory. A number of statistic based parameters have been extracted. Linear relationships between gas-chromatographic retention index (RI) of 62 PCNs in a non-polar column (DB-5) and the structural descriptors have been established by stepwise multiple regression technique. The result shows that two quantities derived from electrostatic potential on molecular surface, ∑Vs- and σ+^2, together with the number of chlorine ( NCl ) and the energy of the highest occupied molecular orbital (EHOMO) can be well used to express the quantitative structure-retention relationship (QSRR) of PCNs. Predictive capability of the model has been demonstrated by leave-one-out cross-validation with the cross-validated correlation coefficient (Rcv^2) of 0.997, and further compared with the results from similar researches published recently. Furthermore, when splitting the 62 PCNs into training and validation sets in the ratio of 2:1, a similar treatment yields an equation of almost equal statistical quality and very similar regression coefficients, validating the robustness and prediction capability of our model. The QSRR model established may provide a new powerful method for predicting chromatographic properties of polychlorinated naphthalenes.
基金Supported by the National Natural Science Foundation of China(20873103)
文摘In this research, the hydrogen bonds Y···H-X (X = C, N; Y = N, O) of thymine and uracil have been theoretically studied. The results show that hydrogen bond leads to bond length elongation and stretches the frequency red-shift of N-H···Y. Meanwhile, the C-H···O bonds shorten and stretch the frequency blue-shift. They all belong to traditional hydrogen bonds. The intermolecular charge transfer caused by the intermolecular hyperconjugation s*(N–H) → n(Y) and intramolecular charge redistribution by intramolecular hyperconjugation σ(C-H) →σ*(C-N) play important roles in the formation of hydrogen bonds. According to thejudgment standards proposed by Bader and Popelier, these hydrogen bonds have typical electron density topological properties. Electrostatic surface potential (ESP) is a useful physicochemical property of a molecule that provides insights into inter- and intramolecular associations, as well as the prediction of likely sites of electrophilic and nucleophilic metabolic attack.
基金supported by Drug Innovation Major Project (Nos. 2018ZX09711001–001–015, 2018ZX09711001–003– 022)CAMS Innovation Fund for Medical Sciences (No. 2016I2M-3–007)。
文摘Rhein(Rhe), an anthraquinone derivative, exhibits excellent anti-inflammatory effects and other pharmacological activities, but its clinical application remains limited due to poor solubility. The present work aims at the improvement of solubility and oral bioavailability of Rhe through cocrystal formation. For this purpose, Rhe and matrine(Mat) were selected as pharmaceutical ingredient(API) and cocrystal former(CCF), respectively, and the Rhe-Mat cocrystal was synthesized and characterized by single crystal X-ray diffraction(SXRD), powder X-ray diffraction(PXRD), thermogravimetric analysis(TGA), differential scanning calorimetry(DSC). The formation mechanism of Rhe-Mat cocrystal was elucidated by molecular surface electrostatic potential(MSEP). It is worth mentioning that the 50-fold increment of dissolution in vitro was observed in pure water in the form of Rhe-Mat cocrystal. Furthermore, the in vivo studies revealed that Rhe-Mat cocrystal indicated the faster absorption rate and the higher peak blood concentration than the pure Rhe. Hence, it can be concluded that current study successfully improved the solubility and oral bioavailability of Rhe.