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.

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.

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.

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.

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.

New insight into pyrrolic-N site effect towards the first NIR window absorption of pyrrolic-N-rich carbon dots

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.

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.

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.

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.

Insight understanding into influence of binding mode of carboxylate with metal ion on ligand-centered luminescence properties in Pb-based coordination polymers

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.

Fluorine Effects for Tunable C-C and C-S Bond Cleavage in Fluoro-Julia-Kocienski Intermediates

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.