THE FRONTIER ORBITALS OF BUCKMINSTERFULLERENE C_(60)

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).

Character of Frontier Orbitals of Antiviral Drugs: Candidate Drugs against Covid-19

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 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 viewpoint, we suggest T-705RTP is a CTP analogue and dihydroxy GS-441524 triphosphate is an ATP analogue.

Selective depression effect in flotation separation of copper-molybdenum sulfides using 2,3-disulfanylbutanedioic acid

2,3-disulfanylbutanedioic acid（DMSA） was found to be a selective depressant in the flotation separation of coppermolybdenum sulfides.The flotation results suggest that a low dosage of DMSA has a strong depression effect on chalcopyrite in the p H range between 4 and 12.At p H 6,the recoveries of molybdenum are up to 85%,75%,and 80% while those of chalcopyrite are 15%,5%,and 20% respectively when flotation tests are carried out with single minerals,mixed minerals and molybdenum-bearing copper concentrates.Adsorption isotherms measurement indicates that DMSA adsorbs more strongly on chalcopyrite than on molybdenite.The frontier orbital calculation reveals that the two S atoms of DMSA molecule are active centers for the adsorption of the DMSA molecule on chalcopyrite surface.Fermi level calculation shows that chalcopyrite can obtain electrons from the DMSA molecule while molybdenite cannot.

Influence of dye molecular structure on electron transfer in 2,9,16,23-tetracarboxy zinc phthalocyanine sensitized solar cell

2, 9, 16, 23-tetracarboxy zinc phthalocyanine （ZnTCPc） is synthesized and characterized by physicochemical and theoretical methods and it is used as a photosensitizer in dye-sensitized solar cells （DSSC）. The excited lifetime, band gap and frontier orbital distribution of ZnTCPc are investigated by fluorescence spectra, cyclic voltammetry and quantum calculation. The results show that the excited lifetime and band gap are 0. 1 ns and 1.81 eV, respectively. Moreover, it is found that the highest occupied molecular orbital （HOMO） location is not shared by both the zinc metal and the isoindoline ligands, and the lowest unoccupied molecular orbital（LUMO） location does not strengthen the interaction coupling between ZnTCPc and TiO：. As a result, the ZnTCPc-DSSC gains a short-circuit current density of 0. 147 mA/cm2, an open-circuit photovoltage of 277 mV, a fill factor of 0. 51 and an overall conversion efficiency of 0. 021%.

Molecular structures and activity of organic depressants for marmatite,jamesonite and pyrite flotation

Ten kinds of organic depressants were used to investigate the depressing performance on marmatite and pyrite.Flotation results show that the organic compounds only with single group of hydroxyl(-OH),carboxyl(-COOH) or amino(-NH2) in molecule are ineffective in depressing marmatite,jamesonite and pyrite.The combinations of these functional groups still cannot enhance the depressing ability of organic depressant.The thioglycollic acid containing reductive functional group(-SH) has a good depressing performance for marmatite and pyrite.The presence of benzene ring in molecule can enhance the depressing performance.The functional group electronegativity,hydrophilic-hydrophobic indexes and frontier orbital of organic depressants were calculated,and the criterion for the depressing effect of organic depressants to sulphide minerals was proposed.

Quantitative structure-activity relationships for joint toxicity of substituted phenols and anilines to Scenedesmus obliquus

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.

Prediction of Toxicity of Phenols and Anilines to Algae by Quantitative Structure-activity Relationship

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.

An X-ray and DFT Computational Study on 1-(Naphthalene-2-yl)-2-(1H-pyrazol-1-yl) ethanone O-butyl Oxime

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.

Comparative Investigation of QHS and DQHS with Density Functional Theory

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.

ADSORPTION MECHANISM OF SOME BIVALENT HEAVY METAL CATIONS IN SOLUTIONS USING MONTMORILLONITE

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.

Selenium-doped cathode materials with polyaniline skeleton for lithium-organosulfur batteries

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.

Theoretical Study on the Electronic Structures and Spectral Properties of 1,8-Naphthalimide Derivatives

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.

Molecular Dynamics Insights into Electron-Catalyzed Dissociation Repair of Cyclobutane Pyrimidine Dimer

Excess electrons are not only an important source of radiation damage,but also participate in the repair process of radiation damage such as cyclobutane pyrimidine dimer(CPD).Using ab initio molecular dynamics(AIMD)simulations,we reproduce the single excess electron stepwise catalytic CPD dissociation process in detail with an emphasis on the energy levels and molecular structure details associated with excess electrons.On the basis of the AIMD simulations on the CPD aqueous solution with two vertically added excess electrons,we exclude the early-proposed[2+2]-like concerted synchronous dissociation mechanism,and analyze the difference between the symmetry of the actual reaction and the symmetry of the frontier molecular orbitals which deeply impact the mechanism.Importantly,we propose a new model of the stepwise electron-catalyzed dissociation mechanism that conforms to the reality.This work not only provides dynamics insights into the excess electron catalyzed dissociation mechanism,but also reveals different roles of two excess electrons in two bond-cleavage steps(promoting versus inhibiting).

Theoretical Study of 1,3-Dipolar Cycloaddition of Hydrazoic Acid to Substituted Ynamines

The 1,3-dipolar cycloaddition reactions of various substituted ynamines with hydrazoic acid were theoretically investigated with the high-accuracy CBS-QB3 method. Two regioisomers, 4-amine, and 5-amine substituted adducts, were obtained, with the former as the preferred yield. This regioselectivity is rationalized by the frontier molecular orbital theory. The reactivity and synchronicity are enhanced with the increase of the electron-withdrawing character of the substitute on ynamine fragment. The calculations also show that the effect of solvent increases the activation energy, and the reaction becomes even harder in polar solvent.

Synthesis and Structural Investigations of New 4-Hexyl-1-(4-nitrophenyl)-1-H-1,2,3-triazole:An Experimental and Theoretical Insight

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.

Theoretical Studies on Structural and Spectroscopic Properties of Photoelectrochemical Cell Ruthenium Sensitizers―the Derivatives of N3

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.

THEORETICAL ANALYSIS OF HYDROGENATION MECHANISM CATALYZED BY Pd-Fe_2O_3/D_(3520)

The mechanism of catalytic hydrogenation of styrene is analyzed by catalysis theory and frontier molecular orbital theory.

First-principles theory on electronic structure and floatability of spodumene

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.

调节Co_(3)O_(4)的价电子结构提高硝酸根还原制氨的催化活性

通过硝酸根电化学还原反应将NO_(3)^(-)转化为NH_(3)是一种有前景的制氨和“绿氢”储存方案.Co_(3)O_(4)对于硝酸根还原析氨反应表现出较高的析氨法拉第效率和稳定性,有望成为理想的催化剂.然而,在Co_(3)O_(4)上发生硝酸根还原反应仍需较高的过电位,从而阻碍了能量转换效率的提升.本文中,我们合成了Cu掺杂Co_(3)O_(4)多孔空心纳米球用作硝酸根还原析氨催化剂.Cu掺杂在保障析氨法拉第效率和稳定性的前提下大幅降低了反应所需的过电位,有效提高了析氨速率.实验和理论分析均表明,Cu掺杂使Co_(3)O_(4)的最高占据态能量上移,缩小了Co_(3)O_(4)的最高占据态与NO_(3)^(-)的最低未占据分子轨道之间的能垒,从而降低了电子从Co_(3)O_(4)向NO_(3)^(-)跃迁所需的过电位,赋予了Cu掺杂Co_(3)O_(4)多孔空心纳米球优异的硝酸根还原析氨电催化活性和耐久性.本研究为纳米材料的电化学性能调控研究提供了新的理论视角.

Quantum-chemical study on the catalytic activity of Ti_nRu_mO_2(110)surfaces on chlorine evolution

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.