Optimized calculation of dibenzofuran （DF） and 135 polychlorinated dibenzofurans （PCDFs） was carried out at the B3LYP/6-31G＊ level in GAUSSIAN 98 program. Based on the theoretical linear solvation energy relation...Optimized calculation of dibenzofuran （DF） and 135 polychlorinated dibenzofurans （PCDFs） was carried out at the B3LYP/6-31G＊ level in GAUSSIAN 98 program. Based on the theoretical linear solvation energy relationship （TLSER） model, the obtained structural parameters were taken as theoretical descriptors to establish the novel quantitative structureproperty relationship （QSPR） model for predicting n-octanol/water partition coefficients （lgKow） of PCDFs. The new model of lgKow achieved in this work contains three variables： energy of the highest occupied molecular orbital （EHOMO）, the most negative atomic partial charge （q^-） and average molecular polarizability （a）, of which R^2= 0.9011 and SD = 0,17 with larger t values. In addition, the variation inflation factors （VIF） of variables in the present model are all less than 5.5, suggesting high accuracy of the lgKow model. And the results of cross-validation test （q^2 = 0.8688） and method validation also show this model exhibits optimum stability and better predictive power than semi-empirical method. At the same time, it is found that the aqueous solubility （-lgSw） has high relative correlation with constant volume molar heat capacity （Cv^0）, of which R^2 = 0.9777 and SD = 0.22. Moreover, lgKow and -lgSw values of all PCDF congeners were predicted respectively.展开更多
A Density functional theory method within generalized gradient approximation has been performed to obtain the static lattice parameters, oxygen positional parameter, bond length and bond angle and electronic propertie...A Density functional theory method within generalized gradient approximation has been performed to obtain the static lattice parameters, oxygen positional parameter, bond length and bond angle and electronic properties of ideal Lu2Sn207 pyrochlore. The results are in excellent agreement with available experimental measurements. Density of states （DOS） of this compound was presented and analysed. We also notice the presence of the hybridization between oxygen and Lu metal. The band structure calculations show that the compound has direct band gap of 2.67 eV at the F point in the Brillouin zone and this indicates that the material has a semi-conducting feature.展开更多
This study focuses on the design,synthesis,and characterization of a novel class of supramolecular polymer networks(SPNs)whose architecture and dynamics are precisely regulated by dynamic covalent chemistry(DCC).The i...This study focuses on the design,synthesis,and characterization of a novel class of supramolecular polymer networks(SPNs)whose architecture and dynamics are precisely regulated by dynamic covalent chemistry(DCC).The integration of dynamic covalent bonds,specifically reversible imine bonds,within a flexible poly(ethylene glycol)(PEG)-based network backbone aims to create materials that synergistically combine robust mechanical properties with efficient self-healing capabilities.The networks were constructed via a one-pot condensation reaction between a difunctional PEG-diamine and a trifunctional aldehyde,benzene-1,3,5-tricarbaldehyde.By systematically varying the stoichiometric ratio between the amine and aldehyde functional groups,as well as the molecular weight of the PEG-diamine,a series of networks with tunable crosslink density and dynamics were obtained.The structural integrity,thermal properties,and viscoelastic behavior of the resulting materials were thoroughly investigated using Fourier-transform infrared spectroscopy(FT-IR),thermal gravimetric analysis(TGA),differential scanning calorimetry(DSC),and dynamic mechanical analysis(DMA).The self-healing performance was quantitatively evaluated through macroscopic damage-repair experiments and the recovery of mechanical properties,including tensile strength and fracture strain.The results demonstrate that an optimal balance between network stability and bond exchange kinetics is crucial for achieving autonomous self-healing at mild conditions without external intervention.Networks with moderate crosslink density exhibited the most promising performance,showcasing high healing efficiency(>92%recovery in tensile strength after 12 hours at 50℃)while maintaining adequate structural integrity.This work provides fundamental insights into the structure-property relationships in DCC-regulated SPNs and outlines a versatile strategy for fabricating advanced self-healing polymeric materials for applications in soft robotics,wearable electronics,and sustainable coatings.展开更多
The unique mathematical perspectives and principal concepts of topology have not only promoted the development of other branches of mathematics but have also deeply influenced other subjects,particularly physics and c...The unique mathematical perspectives and principal concepts of topology have not only promoted the development of other branches of mathematics but have also deeply influenced other subjects,particularly physics and chemistry.This minireview aims to elucidate the substantial influence of topology on chemistry by critically examining both the contributions of topology to current chemical science and its potential future impacts.We will discuss the topology of molecular structures and assemblies across various scales—from small molecules and mechanically interlocked molecules to polymers,biomacromolecules,and supramolecular networks.This discussion will include an exploration of cutting-edge techniques for characterizing topological features,underscoring the role of topology as a novel paradigm for the design and synthesis of new molecular assemblies.Furthermore,a critical analysis of topology’s role in the development of functional materials—such as photonic materials,polymers,biomacromolecules,and chiral materials—will demonstrate its emerging significance as a crucial parameter in unveiling novel properties and functionalities.Given topology’s formidable potential,it is anticipated to be used increasingly to address pivotal challenges within chemistry and adjacent disciplines.展开更多
基金This work was supported by the China Postdoctoral Science Foundation (No. 2003033486)
文摘Optimized calculation of dibenzofuran （DF） and 135 polychlorinated dibenzofurans （PCDFs） was carried out at the B3LYP/6-31G＊ level in GAUSSIAN 98 program. Based on the theoretical linear solvation energy relationship （TLSER） model, the obtained structural parameters were taken as theoretical descriptors to establish the novel quantitative structureproperty relationship （QSPR） model for predicting n-octanol/water partition coefficients （lgKow） of PCDFs. The new model of lgKow achieved in this work contains three variables： energy of the highest occupied molecular orbital （EHOMO）, the most negative atomic partial charge （q^-） and average molecular polarizability （a）, of which R^2= 0.9011 and SD = 0,17 with larger t values. In addition, the variation inflation factors （VIF） of variables in the present model are all less than 5.5, suggesting high accuracy of the lgKow model. And the results of cross-validation test （q^2 = 0.8688） and method validation also show this model exhibits optimum stability and better predictive power than semi-empirical method. At the same time, it is found that the aqueous solubility （-lgSw） has high relative correlation with constant volume molar heat capacity （Cv^0）, of which R^2 = 0.9777 and SD = 0.22. Moreover, lgKow and -lgSw values of all PCDF congeners were predicted respectively.
基金supported by the Scientific Research Foundation of the Education Bureau of Sichuan Province of China (Grant No.2010ZC119)
文摘A Density functional theory method within generalized gradient approximation has been performed to obtain the static lattice parameters, oxygen positional parameter, bond length and bond angle and electronic properties of ideal Lu2Sn207 pyrochlore. The results are in excellent agreement with available experimental measurements. Density of states （DOS） of this compound was presented and analysed. We also notice the presence of the hybridization between oxygen and Lu metal. The band structure calculations show that the compound has direct band gap of 2.67 eV at the F point in the Brillouin zone and this indicates that the material has a semi-conducting feature.
文摘This study focuses on the design,synthesis,and characterization of a novel class of supramolecular polymer networks(SPNs)whose architecture and dynamics are precisely regulated by dynamic covalent chemistry(DCC).The integration of dynamic covalent bonds,specifically reversible imine bonds,within a flexible poly(ethylene glycol)(PEG)-based network backbone aims to create materials that synergistically combine robust mechanical properties with efficient self-healing capabilities.The networks were constructed via a one-pot condensation reaction between a difunctional PEG-diamine and a trifunctional aldehyde,benzene-1,3,5-tricarbaldehyde.By systematically varying the stoichiometric ratio between the amine and aldehyde functional groups,as well as the molecular weight of the PEG-diamine,a series of networks with tunable crosslink density and dynamics were obtained.The structural integrity,thermal properties,and viscoelastic behavior of the resulting materials were thoroughly investigated using Fourier-transform infrared spectroscopy(FT-IR),thermal gravimetric analysis(TGA),differential scanning calorimetry(DSC),and dynamic mechanical analysis(DMA).The self-healing performance was quantitatively evaluated through macroscopic damage-repair experiments and the recovery of mechanical properties,including tensile strength and fracture strain.The results demonstrate that an optimal balance between network stability and bond exchange kinetics is crucial for achieving autonomous self-healing at mild conditions without external intervention.Networks with moderate crosslink density exhibited the most promising performance,showcasing high healing efficiency(>92%recovery in tensile strength after 12 hours at 50℃)while maintaining adequate structural integrity.This work provides fundamental insights into the structure-property relationships in DCC-regulated SPNs and outlines a versatile strategy for fabricating advanced self-healing polymeric materials for applications in soft robotics,wearable electronics,and sustainable coatings.
基金financially supported by the science and technology activity program of the National Natural Science Foundation of China(grant no.22242005)。
文摘The unique mathematical perspectives and principal concepts of topology have not only promoted the development of other branches of mathematics but have also deeply influenced other subjects,particularly physics and chemistry.This minireview aims to elucidate the substantial influence of topology on chemistry by critically examining both the contributions of topology to current chemical science and its potential future impacts.We will discuss the topology of molecular structures and assemblies across various scales—from small molecules and mechanically interlocked molecules to polymers,biomacromolecules,and supramolecular networks.This discussion will include an exploration of cutting-edge techniques for characterizing topological features,underscoring the role of topology as a novel paradigm for the design and synthesis of new molecular assemblies.Furthermore,a critical analysis of topology’s role in the development of functional materials—such as photonic materials,polymers,biomacromolecules,and chiral materials—will demonstrate its emerging significance as a crucial parameter in unveiling novel properties and functionalities.Given topology’s formidable potential,it is anticipated to be used increasingly to address pivotal challenges within chemistry and adjacent disciplines.
