The frontier orbitals HOMO and LUMO of the fullerene C_(60) has been given in a system of 60 motion-coordinates, of which each origin is at each C atom of fullerene C_(60) and each z-axis is in the direction perpendic...The frontier orbitals HOMO and LUMO of the fullerene C_(60) has been given in a system of 60 motion-coordinates, of which each origin is at each C atom of fullerene C_(60) and each z-axis is in the direction perpendicular to C_(60)'S spherical surface. In this motion-coordinate system the HOMO and LUMO of fullerene C_(60) obviously display characteristics of spherical n-molecular orbitals π_n. The Fenske-Hall quantum-chemical method is used in calculation for the electronic structure of the fullerene C_(60).展开更多
We performed density functional theory (DFT) calculations for ribonucleotides and active triphosphate metabolites of candidate drugs against Coronavirus disease 2019 (Covid-19). Frontier orbitals (highest occupied mol...We performed density functional theory (DFT) calculations for ribonucleotides and active triphosphate metabolites of candidate drugs against Coronavirus disease 2019 (Covid-19). Frontier orbitals (highest occupied molecular orbital and lowest unoccupied molecular</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">orbital) at optimized structure of each molecule were obtained. T-705RTP (active triphosphate metabolite of favipiravir) and cytidine triphosphate (CTP) have similar shapes of frontier orbitals. We also obtained similar shapes of frontier orbitals among dihydroxy GS-441524 triphosphate (GS-441524 is an active triphosphate metabolite of remdesivir) and adenosine triphosphate (ATP). From a theoretical </span><span style="font-family:Verdana;">viewpoint, we suggest T-705RTP is a CTP analogue and dihydroxy GS-441524</span><span style="font-family:Verdana;"> triphosphate is an</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">ATP analogue.展开更多
Sulfur-containing polymer(SCP)is considered as an outstanding cathode material for lithium-sulfur batteries.However,undesirable soluble polysulfides may shuttle in electrolyte,concluding long-chain Li_(2)S_(n)(n>4)...Sulfur-containing polymer(SCP)is considered as an outstanding cathode material for lithium-sulfur batteries.However,undesirable soluble polysulfides may shuttle in electrolyte,concluding long-chain Li_(2)S_(n)(n>4)and short-chain Li2Sn(n≤4),as well as the sluggish conversion kinetics are yet to be solved to enhance the performance of lithium-sulfur batteries.Here Se-doped sulfurized polyaniline with adjusted sulfur-chain-S_(x)-(x≤6)contribute to ensure the absence of long-chain polysulfides,and the skeleton with quinoid imine can endow strongly adsorption towards short-chain polysulfides by the reversible transition between deprotonated/protonated imine(-NH^(+)=and-N=),which offer double insurance against suppressing“shuttle effect”.Furthermore,Se atoms are doped into sulfurized polysulfides to accelerate the redox conversion and take a frontier orbital theory-oriented view into catalytic mechanism.Se-doped sulfurized polyaniline as active materials for lithium-organosulfur batteries delivers good electrochemical performance,including high rate,reversible specific capacity(680 mA h g^(-1)at 0.1 A g^(-1)),and lower capacity decay rate only of 0.15%with near 100%coulomb efficiency during long-term cycle.This work provides a valuable guiding ideology and promising solution for the chemistry-oriented structure design and practical application for lithium-organosulfur batteries.展开更多
There are often many chemicals coexisting in aquatic ecosystems, and few information on the joint toxicity of a mixture of organic pollutants is available at present. The 48-h toxicity of substituted phenols and anili...There are often many chemicals coexisting in aquatic ecosystems, and few information on the joint toxicity of a mixture of organic pollutants is available at present. The 48-h toxicity of substituted phenols and anilines and their binary mixtures to Scenedesmus obliquus was determined by the algae inhibition test. The median effective inhibition concentration EC50 values for single compounds and EC50mix values for coexistent compounds were obtained. The n-octanol/water partition coefficient (logPmlx) and the frontier orbital energy gap (AEmlx) for mixtures were calculated. The following two-descriptor quantitative structure-activity relationships (QSARs) models were developed to predict single toxicity and joint toxicity respectively: log(1/ECs0) = 0.445logP - 0.801AE + 9.501 (r2 = 0.876) and log (1/EC50mix) = 0.338logPmix- 0.492AEmix + 6.928 (r^2 = 0.831). The two equations were found to fit well. In addition, the model derived from the structural parameters of single components in binary mixtures log(1/EC50mix) = 0.2221ogP - 0.277AE + 5.250 (r^2 = 0.879) can be used successfully to predict the toxicity of a mixture.展开更多
Objective To measure the toxicity of phenol, aniline, and their derivatives to algae and to assess, model, and predict the toxicity using quantitative structure-activity relationship (QSAR) method. Methods Oxygen pr...Objective To measure the toxicity of phenol, aniline, and their derivatives to algae and to assess, model, and predict the toxicity using quantitative structure-activity relationship (QSAR) method. Methods Oxygen production was used as the response endpoint for assessing the toxic effects of chemicals on algal photosynthesis. The energy of the lowest unoccupied molecular orbital (ELUMO) and the energy of the highest occupied molecular orbital (EHOMO) were obtained from the ChemOffice 2004 program using the quantum chemical method MOPAC, and the frontier orbital energy gap (△E) was obtained. Results The compounds exhibited a reasonably wide range of algal toxicity. The most toxic compound was α-naphthol, whereas the least toxic one was aniline. A two-descriptor model was derived from the algal toxicity and structural parameters: logl/EC50=0.2681ogKow-1.006△E+11.769 (n=20, r^2=0.946). This model was stable and satisfactory for predicting toxicity. Conclusion Phenol, aniline, and their derivatives are polar narcotics. Their toxicity is greater than estimated by hydrophobicity only, and addition of the frontier orbital energy gap AE can significantly improve the prediction of logKow-dependent models.展开更多
The electronic structures of QHS and DQHS were completely optimized and calculated by B3LYP density functional theory at the 6-31g* level. The relationship between electronic structure parameters and antimalarial acti...The electronic structures of QHS and DQHS were completely optimized and calculated by B3LYP density functional theory at the 6-31g* level. The relationship between electronic structure parameters and antimalarial activity was discussed. There exists significant difference in frontier orbitals of QHS and DQHS. Their net charges and bond orders were also compared respectively. The results of calculation prove theoretically that the endoperoxy bridge is the essential of antimalarial activity. The difference of antimalarial activity between QHS and DQHS was reasonably explained based on their electronic structures.展开更多
The frontier orbital energies of montmorillonite molecule and[Me(H_(2)O)_(6)]^(2+)(Me=Cu^(2+),Zn^(2+),Co^(2+)and Ni^(2+))were calculated by INDO method.Results showed that the chemical interaction between montmorillon...The frontier orbital energies of montmorillonite molecule and[Me(H_(2)O)_(6)]^(2+)(Me=Cu^(2+),Zn^(2+),Co^(2+)and Ni^(2+))were calculated by INDO method.Results showed that the chemical interaction between montmorillonite molecule and[Cu(H_(2)O)_(6)]^(2+)or[Zn(H_(2)O)_(6)]^(2+)was possible.The experimental results of powder X-ray diffraction and isothermal adsorption supported the above-mentioned calculation results.展开更多
The title compound, 1-(naphthalene-2-yl)-2-(1H-pyrazol-1-yl)ethanone O-butyl oxime, I, was synthesized. The crystal and molecular structures of I were determined by IR, 1H-NMR, mass spectrum, elemental analysis an...The title compound, 1-(naphthalene-2-yl)-2-(1H-pyrazol-1-yl)ethanone O-butyl oxime, I, was synthesized. The crystal and molecular structures of I were determined by IR, 1H-NMR, mass spectrum, elemental analysis and X-ray single crystal diffraction. Molecular geometry from X-ray experiment of I in the ground state was compared using the Density Functional Theory (DFT) with B3LYP/6-311G(d,p) basis set. In addition, DFT calculation, molecular electrostatic potentials (MEP) and frontier molecular orbitals of I were performed at the B3LYP/6-311G(d,p) level of the theory.展开更多
The molecular geometries, frontier molecular orbital properties, and absorption and emission properties of three 4-phenoxy-1,8-naphthalimide derivatives, namely 4-phenoxy-N-(2-hydroxyethyl)-1,8-naphthalimide(1),4-...The molecular geometries, frontier molecular orbital properties, and absorption and emission properties of three 4-phenoxy-1,8-naphthalimide derivatives, namely 4-phenoxy-N-(2-hydroxyethyl)-1,8-naphthalimide(1),4-(2-tert-butylphenoxy)-N-(2-hydroxyethyl)-1,8-naphthalimide(2), and 4-[2,4-di(tert-butyl)]phenoxy-N-(2-hydroxyethyl)-1,8-naphthalimide(3), are investigated by density functional theory(DFT) and time-dependent density functional theory(TD-DFT) calculations in conjunction with polarizable continuum models(PCMs). Four functionals and ten basis sets are employed for 1 to calculate the electron transition energies, which were compared with the experimental observations. Our results reveal that the B3LYP/6-311+G(d,p) method is the best choice to reproduce the experimental spectra. Moreover, the effects of substituents on the molecular geometries, electronic structures, absorption and emission spectra are also studied at the B3LYP/6-311+G(d,p) level. We find that the gap between the highest occupied molecular orbital(HOMO) and the lowest unoccupied molecular orbital(LUMO) decreases with increasing the number of tert-butyl substituents onto the phenoxy groups, suggesting red-shift of the absorption and emission bands. This is related to the increase of conjugation from 1 to 2 and 3. Our calculations are in good agreement with the experimental results.展开更多
The title compound, 4-hexyl-1-(4-nitrophenyl)-1-H-1,2,3-triazole (CI4HIsN402), was synthesized using one-pot strategy via click reaction and the structure was characterized mainly by single-crystal X-ray diffracti...The title compound, 4-hexyl-1-(4-nitrophenyl)-1-H-1,2,3-triazole (CI4HIsN402), was synthesized using one-pot strategy via click reaction and the structure was characterized mainly by single-crystal X-ray diffraction, NMR, FT-IR and MS. C14H18N4O2 was crystallized from an EtOH/EtOAc solution in triclinic system, space group PI, with a = 5.3679(3), b = 7.5499(5), c = 17.5534(11) A, a = 92.360(4), β = 90.359(4), γ = 98.864(4)°, V (A3) = 702.24(8), Z = 2, crystal size (mm) = 0.42 × 0.26 × 0.18, Rint = 0.096. Packing diagram indicates that there is dimeric interaction between two units via N(3)...H(6). The crystal structure of the title compound (1) is stabifized by intermolecular interactions. In addition, X-ray analys!s also reveals C-H…π and π-π interactions in the molecule. Theoretical investigations were performed by using Gaussian 09 software at the B3LYP/6, 31G (d,p)level of density,finctional theory (DFT).to compare the theoretical results with the experimental and to probe structural properties. The molecular electrostatic potential (MEP) mapped over the entire stabilized geometry of the molecule indicated their chemical reactivities. Furthermore, frontier molecular orbital (electronic properties) was computed at the same level of DFT as used. forenergy minima structure.展开更多
A series of dye molecules was designed theoretically.Particularly,azoles and their derivatives were chosen as the modifying groups linking to ancillary ligands of [Ru(dcbpyH2)2(NCS)2](N3,dcbpy=4,4'-dicarboxy2,2...A series of dye molecules was designed theoretically.Particularly,azoles and their derivatives were chosen as the modifying groups linking to ancillary ligands of [Ru(dcbpyH2)2(NCS)2](N3,dcbpy=4,4'-dicarboxy2,2'-bipyridine;NCS=thiocyanato).Density functional theory(DFT) based approaches were applied to exploring the electronic structures and properties of all these systems.The dye molecule with 1,2,4-triazole groups which exhibits a very high intensity of absorption in visible region,was obtained.Time-dependent DFT(TD-DFT) results indicate that the ancillary ligand dominates the molecular orbital(MO) energy levels and masters the absorption transition nature to a certain extent.The deprotonation of anchoring ligand not only affects the frontier MO energy levels but also controls the energy gaps of the highest occupied MO(HOMO) to the lowest unoccupied MO(LUMO) and LUMO to LUMO+1 orbital.If the gap between LUMO-LUMO+1 is small enough,the higher efficiency of dye-sensitized solar cell(DSSC) should be expected.展开更多
Controlled C-N configurations,i.e.,pyrrolic-N,pyridinic-N,and graphitic-N,are promising strategies to tailor the carbon dots’(CDs)optical properties into the first near infrared(NIR)window(650-900 nm),a responsive ra...Controlled C-N configurations,i.e.,pyrrolic-N,pyridinic-N,and graphitic-N,are promising strategies to tailor the carbon dots’(CDs)optical properties into the first near infrared(NIR)window(650-900 nm),a responsive range for biomedical application.However,a deep understanding of the role of the C-N configuration in the CDs’properties is still challenging and thoughtprovoking owing to their complex structure.Here,an underlying pyrrolic-N concentration and position effect on the pyrrolic-N-rich CDs’absorption was comprehensively elucidated based on the integrated experimental and computational studies.The assynthesized pyrrolic-N-rich CDs exhibit a first NIR window absorption centered at 650 nm with high photothermal conversion.Pyrrolic-N concentrations from 1.4%to 11.3%and positions(edge and mid-site)were systematically investigated.A mid-site pyrrolic-N was subsequently generated after the pyrrolic-N concentration more than 10%.Edge-site pyrrolic-N induces a frontier orbital hybridization,reducing bandgap energy,while mid-site pyrrolic-N plays a critical role in inducing a first NIR window absorption owing to their high charge transfer.Also,pyrrolic-N-rich CDs inherit a bowl-like topological feature,elevating the CDs’layer thickness as much as 0.71 nm.This study shed light on the design and optimization of pyrrolic-N on CDs for the first NIR window responsive materials in any biomedical application.展开更多
The band structure, density of states, Mulliken populations, and frontier orbital of spodumene crystal were calculated using the first-principles method based on the density functional theory(DFT) and further analyz...The band structure, density of states, Mulliken populations, and frontier orbital of spodumene crystal were calculated using the first-principles method based on the density functional theory(DFT) and further analyzed in detail. The calculation results reveal that the O in spodumene is the most active and easily links with H+in the water, but the active Li is very low, so it is better to add activator to increase the concentrate grade and recovery rate of spodumene in the flotation process. Si–O bonds in spodumene crystal are mainly covalent, since the covalency of Al–O bonds is stronger than that of Li–O bonds,and minerals dissociate along the weakest Li–O bonds. In addition, the study of the frontier orbital indicates that both O and Si atoms have large contribution to the frontier orbital in the spodumene crystal. Oleate and dodecylamine are used as the collectors of spodumene. The results contribute to the understanding of crystal structures of spodumene, and can be used in guiding related practical applications.展开更多
In the crystal engineering area,it is important to clearly demonstrating the relationship of structure and certain functionality.Herein,we present the study of the relationship of structure with phosphorescent nature ...In the crystal engineering area,it is important to clearly demonstrating the relationship of structure and certain functionality.Herein,we present the study of the relationship of structure with phosphorescent nature for two new room temperature phosphorescence(RTP) coordination polymers(CPs).[Pb(FDA)(H_(2)O)](1) and [NH_(3)(CH_(3))NH_(2)(CH_(3))_(2)][Pb_(4)(FDA)_(5)](2),where H_(2) FDA is 2,5-furandicarboxylic acid,have been synthesized by solvothermal method using different solvents and Pb^(2+) sources and characterized by microanalysis,powderX-ray diffraction(PXRD),thermogravimetric(TG),IR and UV-vis spectra.The Pb^(2+)ions adopt bicapped triangle prism coordination sphere in 1 and 2,which are connected together via FDA^(2-) ligands into bilayer structure in 1 while pillared-layer framework in 2.The FDA^(2-) ligands show different bridging modes in 1 and 2,leading to distinct coordination interactions between Pb^(2+) ion and FDA^(2-) ligand in both CPs.Both 1 and 2 emit ligand-centered RTP due to the heavy atom of Pb^(2+) ion,with a lifetime and quantum yield of 0.62 ms and 14.9% in 1 versus 1.69 ms and 15.7% in 2.The emission peak shows significant redshift(79 nm) in 2 regarding 1,which arises from their distinction of coordination interactions between Pb^(2+) ion and FDA^(2-) ligand in both CPs.展开更多
Based on the generalized gradient approximation (GGA), Perdew-Wang-91 (PW91) combined with a periodic slab model has been applied to study the catalytic activity of chlorine evolution on TinRumO2 (1 1 0) surface...Based on the generalized gradient approximation (GGA), Perdew-Wang-91 (PW91) combined with a periodic slab model has been applied to study the catalytic activity of chlorine evolution on TinRumO2 (1 1 0) surface. Metal oxide model TinRumO2 has been established with pure TiO2 and Ru02 on the basis set of Double Numerical plus polarization (DNP), in which the proportion of n:m was 3:1, 1 :l, or 1:3. Analysis on the reaction activity in the electrochemical reaction and the electrochemical desorption reaction was based on Frontier molecular orbital theory. The results show that the TinRumO2 with a ratio of Ti:Ru at 3:1 is best facilitates the electrochemical reaction and electrochemical desorption reaction to produce M-Clads intermediate and precipitate C12. In addition, the adsorption energy of Cl on the surface of Ti3RU102 possesses the minimum value of 2.514 eV, and thus electrochemical desorption reaction could occur most easily.展开更多
Classical Julia-Kocienski fluoroolefination represents an indispensable platform for the construction of monofluoroalkenes.Nevertheless,its complex multistep mechanistic manifold along with the unrevealed intrinsic“f...Classical Julia-Kocienski fluoroolefination represents an indispensable platform for the construction of monofluoroalkenes.Nevertheless,its complex multistep mechanistic manifold along with the unrevealed intrinsic“fluorine effect”in nucleophilic reactions might be responsible for the difficult control of the original stereoselectivity and is thus often ambiguous to predict.Herein,a novel strategy involving the defined fluorine effect and new reaction mechanism was developed for tunable C-C and C-S bond cleavage,providing a versatile avenue for highly stereoselective and easily scalable construction of diverse monofluoroalkenes.Density functional theory(DFT)investigations indicate the fluorine substituents can activate the C-C and C-S bond leading toα-elimination by antiphase orbital interaction.The rate-limiting step were calculated via fourmembered transition states with ring strain.Both the sterically eclipsed repulsion and secondary orbital interaction affect the stereoselectivity.展开更多
文摘The frontier orbitals HOMO and LUMO of the fullerene C_(60) has been given in a system of 60 motion-coordinates, of which each origin is at each C atom of fullerene C_(60) and each z-axis is in the direction perpendicular to C_(60)'S spherical surface. In this motion-coordinate system the HOMO and LUMO of fullerene C_(60) obviously display characteristics of spherical n-molecular orbitals π_n. The Fenske-Hall quantum-chemical method is used in calculation for the electronic structure of the fullerene C_(60).
文摘We performed density functional theory (DFT) calculations for ribonucleotides and active triphosphate metabolites of candidate drugs against Coronavirus disease 2019 (Covid-19). Frontier orbitals (highest occupied molecular orbital and lowest unoccupied molecular</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">orbital) at optimized structure of each molecule were obtained. T-705RTP (active triphosphate metabolite of favipiravir) and cytidine triphosphate (CTP) have similar shapes of frontier orbitals. We also obtained similar shapes of frontier orbitals among dihydroxy GS-441524 triphosphate (GS-441524 is an active triphosphate metabolite of remdesivir) and adenosine triphosphate (ATP). From a theoretical </span><span style="font-family:Verdana;">viewpoint, we suggest T-705RTP is a CTP analogue and dihydroxy GS-441524</span><span style="font-family:Verdana;"> triphosphate is an</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">ATP analogue.
基金partly supported by the National Natural Science Foundation of China(51763014 and 52073133)the Key Talent Project Foundation of Gansu Province+3 种基金Joint fund between Shenyang National Laboratory for Materials Science and State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals(18LHPY002)the Incubation Program of Excellent Doctoral Dissertation-Lanzhou University of Technologyexcellent doctoral Program of Gansu Province(22JR5RA240)the Program for Hongliu Distinguished Young Scholars in Lanzhou University of Technology。
文摘Sulfur-containing polymer(SCP)is considered as an outstanding cathode material for lithium-sulfur batteries.However,undesirable soluble polysulfides may shuttle in electrolyte,concluding long-chain Li_(2)S_(n)(n>4)and short-chain Li2Sn(n≤4),as well as the sluggish conversion kinetics are yet to be solved to enhance the performance of lithium-sulfur batteries.Here Se-doped sulfurized polyaniline with adjusted sulfur-chain-S_(x)-(x≤6)contribute to ensure the absence of long-chain polysulfides,and the skeleton with quinoid imine can endow strongly adsorption towards short-chain polysulfides by the reversible transition between deprotonated/protonated imine(-NH^(+)=and-N=),which offer double insurance against suppressing“shuttle effect”.Furthermore,Se atoms are doped into sulfurized polysulfides to accelerate the redox conversion and take a frontier orbital theory-oriented view into catalytic mechanism.Se-doped sulfurized polyaniline as active materials for lithium-organosulfur batteries delivers good electrochemical performance,including high rate,reversible specific capacity(680 mA h g^(-1)at 0.1 A g^(-1)),and lower capacity decay rate only of 0.15%with near 100%coulomb efficiency during long-term cycle.This work provides a valuable guiding ideology and promising solution for the chemistry-oriented structure design and practical application for lithium-organosulfur batteries.
文摘There are often many chemicals coexisting in aquatic ecosystems, and few information on the joint toxicity of a mixture of organic pollutants is available at present. The 48-h toxicity of substituted phenols and anilines and their binary mixtures to Scenedesmus obliquus was determined by the algae inhibition test. The median effective inhibition concentration EC50 values for single compounds and EC50mix values for coexistent compounds were obtained. The n-octanol/water partition coefficient (logPmlx) and the frontier orbital energy gap (AEmlx) for mixtures were calculated. The following two-descriptor quantitative structure-activity relationships (QSARs) models were developed to predict single toxicity and joint toxicity respectively: log(1/ECs0) = 0.445logP - 0.801AE + 9.501 (r2 = 0.876) and log (1/EC50mix) = 0.338logPmix- 0.492AEmix + 6.928 (r^2 = 0.831). The two equations were found to fit well. In addition, the model derived from the structural parameters of single components in binary mixtures log(1/EC50mix) = 0.2221ogP - 0.277AE + 5.250 (r^2 = 0.879) can be used successfully to predict the toxicity of a mixture.
基金This work was supported by the Program for New Century Excellent Talents in University (No. 05-0481)National "973" Great Foundation Research Items of China (No. 2002CB412303)
文摘Objective To measure the toxicity of phenol, aniline, and their derivatives to algae and to assess, model, and predict the toxicity using quantitative structure-activity relationship (QSAR) method. Methods Oxygen production was used as the response endpoint for assessing the toxic effects of chemicals on algal photosynthesis. The energy of the lowest unoccupied molecular orbital (ELUMO) and the energy of the highest occupied molecular orbital (EHOMO) were obtained from the ChemOffice 2004 program using the quantum chemical method MOPAC, and the frontier orbital energy gap (△E) was obtained. Results The compounds exhibited a reasonably wide range of algal toxicity. The most toxic compound was α-naphthol, whereas the least toxic one was aniline. A two-descriptor model was derived from the algal toxicity and structural parameters: logl/EC50=0.2681ogKow-1.006△E+11.769 (n=20, r^2=0.946). This model was stable and satisfactory for predicting toxicity. Conclusion Phenol, aniline, and their derivatives are polar narcotics. Their toxicity is greater than estimated by hydrophobicity only, and addition of the frontier orbital energy gap AE can significantly improve the prediction of logKow-dependent models.
文摘The electronic structures of QHS and DQHS were completely optimized and calculated by B3LYP density functional theory at the 6-31g* level. The relationship between electronic structure parameters and antimalarial activity was discussed. There exists significant difference in frontier orbitals of QHS and DQHS. Their net charges and bond orders were also compared respectively. The results of calculation prove theoretically that the endoperoxy bridge is the essential of antimalarial activity. The difference of antimalarial activity between QHS and DQHS was reasonably explained based on their electronic structures.
文摘The frontier orbital energies of montmorillonite molecule and[Me(H_(2)O)_(6)]^(2+)(Me=Cu^(2+),Zn^(2+),Co^(2+)and Ni^(2+))were calculated by INDO method.Results showed that the chemical interaction between montmorillonite molecule and[Cu(H_(2)O)_(6)]^(2+)or[Zn(H_(2)O)_(6)]^(2+)was possible.The experimental results of powder X-ray diffraction and isothermal adsorption supported the above-mentioned calculation results.
基金the Faculty of Arts and Sciences, Ondokuz Mayιs University, Turkey, for the use of the Stoe IPDSII diffractometer (purchased under grant No. F279 of the University Research Fund)
文摘The title compound, 1-(naphthalene-2-yl)-2-(1H-pyrazol-1-yl)ethanone O-butyl oxime, I, was synthesized. The crystal and molecular structures of I were determined by IR, 1H-NMR, mass spectrum, elemental analysis and X-ray single crystal diffraction. Molecular geometry from X-ray experiment of I in the ground state was compared using the Density Functional Theory (DFT) with B3LYP/6-311G(d,p) basis set. In addition, DFT calculation, molecular electrostatic potentials (MEP) and frontier molecular orbitals of I were performed at the B3LYP/6-311G(d,p) level of the theory.
基金supported by the Scientific Research Fund of Hubei Provincial Education Department(No.Q20122909)the Open Fund of Key Laboratory of Biologic Resources Protection and Utilization of Hubei Province(No.PKLHB1314)the First-class Discipline of Forestry in Hubei Minzu University
文摘The molecular geometries, frontier molecular orbital properties, and absorption and emission properties of three 4-phenoxy-1,8-naphthalimide derivatives, namely 4-phenoxy-N-(2-hydroxyethyl)-1,8-naphthalimide(1),4-(2-tert-butylphenoxy)-N-(2-hydroxyethyl)-1,8-naphthalimide(2), and 4-[2,4-di(tert-butyl)]phenoxy-N-(2-hydroxyethyl)-1,8-naphthalimide(3), are investigated by density functional theory(DFT) and time-dependent density functional theory(TD-DFT) calculations in conjunction with polarizable continuum models(PCMs). Four functionals and ten basis sets are employed for 1 to calculate the electron transition energies, which were compared with the experimental observations. Our results reveal that the B3LYP/6-311+G(d,p) method is the best choice to reproduce the experimental spectra. Moreover, the effects of substituents on the molecular geometries, electronic structures, absorption and emission spectra are also studied at the B3LYP/6-311+G(d,p) level. We find that the gap between the highest occupied molecular orbital(HOMO) and the lowest unoccupied molecular orbital(LUMO) decreases with increasing the number of tert-butyl substituents onto the phenoxy groups, suggesting red-shift of the absorption and emission bands. This is related to the increase of conjugation from 1 to 2 and 3. Our calculations are in good agreement with the experimental results.
基金supported by the Higher Education Commision(HEC)Govt.of Pakistan
文摘The title compound, 4-hexyl-1-(4-nitrophenyl)-1-H-1,2,3-triazole (CI4HIsN402), was synthesized using one-pot strategy via click reaction and the structure was characterized mainly by single-crystal X-ray diffraction, NMR, FT-IR and MS. C14H18N4O2 was crystallized from an EtOH/EtOAc solution in triclinic system, space group PI, with a = 5.3679(3), b = 7.5499(5), c = 17.5534(11) A, a = 92.360(4), β = 90.359(4), γ = 98.864(4)°, V (A3) = 702.24(8), Z = 2, crystal size (mm) = 0.42 × 0.26 × 0.18, Rint = 0.096. Packing diagram indicates that there is dimeric interaction between two units via N(3)...H(6). The crystal structure of the title compound (1) is stabifized by intermolecular interactions. In addition, X-ray analys!s also reveals C-H…π and π-π interactions in the molecule. Theoretical investigations were performed by using Gaussian 09 software at the B3LYP/6, 31G (d,p)level of density,finctional theory (DFT).to compare the theoretical results with the experimental and to probe structural properties. The molecular electrostatic potential (MEP) mapped over the entire stabilized geometry of the molecule indicated their chemical reactivities. Furthermore, frontier molecular orbital (electronic properties) was computed at the same level of DFT as used. forenergy minima structure.
基金Supported by the National Natural Science Foundation of China(Nos.20973076,21003057)the Specialized Research Fund for the Doctoral Program of Higher Education,China(No.20110061110018)
文摘A series of dye molecules was designed theoretically.Particularly,azoles and their derivatives were chosen as the modifying groups linking to ancillary ligands of [Ru(dcbpyH2)2(NCS)2](N3,dcbpy=4,4'-dicarboxy2,2'-bipyridine;NCS=thiocyanato).Density functional theory(DFT) based approaches were applied to exploring the electronic structures and properties of all these systems.The dye molecule with 1,2,4-triazole groups which exhibits a very high intensity of absorption in visible region,was obtained.Time-dependent DFT(TD-DFT) results indicate that the ancillary ligand dominates the molecular orbital(MO) energy levels and masters the absorption transition nature to a certain extent.The deprotonation of anchoring ligand not only affects the frontier MO energy levels but also controls the energy gaps of the highest occupied MO(HOMO) to the lowest unoccupied MO(LUMO) and LUMO to LUMO+1 orbital.If the gap between LUMO-LUMO+1 is small enough,the higher efficiency of dye-sensitized solar cell(DSSC) should be expected.
基金This work was fully supported by the Indonesian Endowment Fund for Education and the Indonesian Science Fund through the International Collaboration RISPRO Funding Program(No.RISPRO/KI/B1/KOM/11/4542/2/2020).
文摘Controlled C-N configurations,i.e.,pyrrolic-N,pyridinic-N,and graphitic-N,are promising strategies to tailor the carbon dots’(CDs)optical properties into the first near infrared(NIR)window(650-900 nm),a responsive range for biomedical application.However,a deep understanding of the role of the C-N configuration in the CDs’properties is still challenging and thoughtprovoking owing to their complex structure.Here,an underlying pyrrolic-N concentration and position effect on the pyrrolic-N-rich CDs’absorption was comprehensively elucidated based on the integrated experimental and computational studies.The assynthesized pyrrolic-N-rich CDs exhibit a first NIR window absorption centered at 650 nm with high photothermal conversion.Pyrrolic-N concentrations from 1.4%to 11.3%and positions(edge and mid-site)were systematically investigated.A mid-site pyrrolic-N was subsequently generated after the pyrrolic-N concentration more than 10%.Edge-site pyrrolic-N induces a frontier orbital hybridization,reducing bandgap energy,while mid-site pyrrolic-N plays a critical role in inducing a first NIR window absorption owing to their high charge transfer.Also,pyrrolic-N-rich CDs inherit a bowl-like topological feature,elevating the CDs’layer thickness as much as 0.71 nm.This study shed light on the design and optimization of pyrrolic-N on CDs for the first NIR window responsive materials in any biomedical application.
基金financially supported by the National Natural Science Foundation of China(11921006)the National Key Research and Development Program of China(2020YFC1909604)+1 种基金Shenzhen Key Projects of Technological Research(JSGG20200925145800001)Shenzhen Science and Technology Program(CJGJZD20210408092801005)。
基金financially supported by the National Natural Science Foundation of China (No. 51104070)the Special Funds for Postgraduate Student Innovation Program of Jiangxi University of Science and Technology (No. YC2012-X07)the Special Funds for Postgraduate Student Innovation Program of Jiangxi province (No. YC2013-S183)
文摘The band structure, density of states, Mulliken populations, and frontier orbital of spodumene crystal were calculated using the first-principles method based on the density functional theory(DFT) and further analyzed in detail. The calculation results reveal that the O in spodumene is the most active and easily links with H+in the water, but the active Li is very low, so it is better to add activator to increase the concentrate grade and recovery rate of spodumene in the flotation process. Si–O bonds in spodumene crystal are mainly covalent, since the covalency of Al–O bonds is stronger than that of Li–O bonds,and minerals dissociate along the weakest Li–O bonds. In addition, the study of the frontier orbital indicates that both O and Si atoms have large contribution to the frontier orbital in the spodumene crystal. Oleate and dodecylamine are used as the collectors of spodumene. The results contribute to the understanding of crystal structures of spodumene, and can be used in guiding related practical applications.
基金the National Natural Science Foundation of China (No.21901116)。
文摘In the crystal engineering area,it is important to clearly demonstrating the relationship of structure and certain functionality.Herein,we present the study of the relationship of structure with phosphorescent nature for two new room temperature phosphorescence(RTP) coordination polymers(CPs).[Pb(FDA)(H_(2)O)](1) and [NH_(3)(CH_(3))NH_(2)(CH_(3))_(2)][Pb_(4)(FDA)_(5)](2),where H_(2) FDA is 2,5-furandicarboxylic acid,have been synthesized by solvothermal method using different solvents and Pb^(2+) sources and characterized by microanalysis,powderX-ray diffraction(PXRD),thermogravimetric(TG),IR and UV-vis spectra.The Pb^(2+)ions adopt bicapped triangle prism coordination sphere in 1 and 2,which are connected together via FDA^(2-) ligands into bilayer structure in 1 while pillared-layer framework in 2.The FDA^(2-) ligands show different bridging modes in 1 and 2,leading to distinct coordination interactions between Pb^(2+) ion and FDA^(2-) ligand in both CPs.Both 1 and 2 emit ligand-centered RTP due to the heavy atom of Pb^(2+) ion,with a lifetime and quantum yield of 0.62 ms and 14.9% in 1 versus 1.69 ms and 15.7% in 2.The emission peak shows significant redshift(79 nm) in 2 regarding 1,which arises from their distinction of coordination interactions between Pb^(2+) ion and FDA^(2-) ligand in both CPs.
基金the Natural Science Foundation of China(No. 51072239)the Fundamental Research Funds for the Central Universities(No.CQDXWL-2012-032) for financial support
文摘Based on the generalized gradient approximation (GGA), Perdew-Wang-91 (PW91) combined with a periodic slab model has been applied to study the catalytic activity of chlorine evolution on TinRumO2 (1 1 0) surface. Metal oxide model TinRumO2 has been established with pure TiO2 and Ru02 on the basis set of Double Numerical plus polarization (DNP), in which the proportion of n:m was 3:1, 1 :l, or 1:3. Analysis on the reaction activity in the electrochemical reaction and the electrochemical desorption reaction was based on Frontier molecular orbital theory. The results show that the TinRumO2 with a ratio of Ti:Ru at 3:1 is best facilitates the electrochemical reaction and electrochemical desorption reaction to produce M-Clads intermediate and precipitate C12. In addition, the adsorption energy of Cl on the surface of Ti3RU102 possesses the minimum value of 2.514 eV, and thus electrochemical desorption reaction could occur most easily.
基金The authors gratefully acknowledge the National Natural Science Foundation of China(nos.21602231,21890722,21702109,and 11811530637)Chinese Academy of Sciences“Light of West China”Program,and the Natural Science Foundation of Jiangsu Province(nos.BK20160396 and BK20191197)+2 种基金the Natural Science Foundation of Tianjin Municipality(nos.18JCYBJC21400 and 19JCJQJC62300)Tianjin Research Innovation Project for Postgraduate Students(no.2019YJSB081)the Fundamental Research Funds for Central Universities[Nankai University(nos.63191515 and 63196021)]for generous financial support.
文摘Classical Julia-Kocienski fluoroolefination represents an indispensable platform for the construction of monofluoroalkenes.Nevertheless,its complex multistep mechanistic manifold along with the unrevealed intrinsic“fluorine effect”in nucleophilic reactions might be responsible for the difficult control of the original stereoselectivity and is thus often ambiguous to predict.Herein,a novel strategy involving the defined fluorine effect and new reaction mechanism was developed for tunable C-C and C-S bond cleavage,providing a versatile avenue for highly stereoselective and easily scalable construction of diverse monofluoroalkenes.Density functional theory(DFT)investigations indicate the fluorine substituents can activate the C-C and C-S bond leading toα-elimination by antiphase orbital interaction.The rate-limiting step were calculated via fourmembered transition states with ring strain.Both the sterically eclipsed repulsion and secondary orbital interaction affect the stereoselectivity.