Spectroscopic Electrochemical Properties and DFT Calculation of 1-Aryltriazenes

Electrochromic materials are of great interest for their potential in eyewear protection and data storage devices, as they change colors in response to electrochemical switching. While many of the systems currently used are based on inorganic materials, organic materials such as triazenes have emerged as viable alternatives due to their unique properties, including optical properties. Triazenes are a class of organic compounds with three consecutive nitrogen atoms in an acyclic arrangement, and they have been used for a variety of applications in medicinal and synthetic chemistry. However, the effects of solvents on the UV-visible absorption spectrum of triazenes have not been fully investigated. The neutral molecules of 3,3-diisopropyl-1-phenyltriazene and 1-(4-chlorophenyl)-3-cyclopentyltriazene in acetonitrile, the UV-visible spectra corresponded respectively to HOMO → LUMO transitions with a large maximum absorption at 299.74 nm (4.1364 eV) and 299.57 nm (4.1387 eV) and the most intense oscillator strength (f = 0.6988) and (f = 0.7372). These results suggest that the electronic transitions of the compounds are highly influenced by the nature of the substituents on the triazene unit, as well as the solvent used in the experiment. The redox couple 0.92 and -0.44 V/Ag/AgCl is attributed to the phenyl group. Compound III showed an oxidation and reduction peak respectively -0.27 and -0.8 V/Ag/AgCl attributed to the phenyl molecule. The study concluded that all three compounds were electroactive and exhibited reversible characteristics with oxidizing/reducing couples. This study aims to contribute to research on the optical properties of triazenes compounds and the application of quantum chemical calculation methods for understanding their molecular structures. By investigating the solute-solvent interactions occurring in the solvation shell of the solutes, we aim to gain insights into the effects of solvents on the UV-visible absorption spectrum of triazenes. Our findings may have implications for the development of functionalized triazenes as potential electrochromic materials.

Structure-activity relationships of oxime compounds as flotation collectors by DFT calculations

The relationships between the structure of oxime compounds(R^(1)R^(2)C=NOH,R^(1)/R^(2)=alkyl groups) with different substituents and their corresponding flotation performances were studied. The analyses of density functional theory(DFT) calculations illustrated that the introduced phenyl group at the R^(1) position could enhance the acidity,while the heptyl group could effectively increase the hydrophobicity and benefit van der Waals interactions. Meanwhile,the introduced amino group at the R^(2) position could provide cationic sites to interact with negatively charged surfaces of minerals, while the introduced hydroxyl group could provide additional action sites to form stable chelates with metal ions. Based on the structure-activity relationships, structural optimization was carried out to obtain three efficient collectors, which possessed superior flotation separation performances, proving the effectiveness of the structural modification to oxime compounds in this work.

S-(+)-(E)-1-(2-furfuryl)-5-substituted-1,3,5-hexahydrotriazine-2-N-nitroimines:Synthesis,Crystal Structure and DFT Calculations

A novel neonicotinoid analogue（C13H19N5O5,3a）had been synthesized,the structure was characterized by elemental analysis,IR and 1H NMR spectra,and the S-（＋）-（E）-configuration was confirmed by single-crystal X-ray diffraction.The crystal belongs to monoclinic,space group P21 with a = 8.7076（17）,b = 8.3211（17）,c = 10.642（2）,β = 92.370（3）o,V = 770.4（3）3,Z = 2,Dc = 1.402 g/cm3,μ = 0.110 mm-1,Mr = 325.33,F（000）= 344,S = 1.027,R = 0.0543 and wR = 0.1229 for 3601 unique reflections with 2919 observed ones（I 2σ（I））.Compound 3a is stabilized by intramolecular hydrogen bonds and intermolecular force.In addition,the structure of compound 3a was optimized by the B3LYP/6-31G（d,p）.DFT/B3LYP optimizations were performed based on X-ray geometries applying 6-31G（d,p）basis set.The optimized structure of compound 3a by the B3LYP/6-31G（d,p）method is more bent than in the crystal.IR spectrum of the solid compound is consistent with the X-ray structure.The HOMO-LUMO gap in 3a（5.3 eV）indicates high kinetic stabilities of compound 3a.The preliminary bioassay test showed that 3a exhibited good activities against Nilaparvata legen,Pseudaletia separate Walker and Aphis medicagini at 500 mg/L.

Structural and Vibrational Study of 2-（Quinolin-8-yloxy）-Acetic Acid based on FT-IR-Raman Spectroscopy and DFT Calculations

We have prepared the 2-（quinolin-8-yloxy）-acetic acid and characterized it by infrared and Raman spectroscopies in the solid phase. The Density Functional Theory （DFT） method, together with the 6-31G^＊ and 6-311＋＋ G^＊＊ basis sets, show that three stable molecules, for the anhydrous and monohydrated compounds were theoretically determined in the gas phase, and that probably the two more stable conformations are present in the solid phase of the monohydrated compound. The harmonic vibrational wavenumbers for the optimized geometries were calculated at B3LYP/6-31G^＊and B3LYP/6-311＋＋G^＊＊ levels. For a complete assignment of all the observed bands in the vibrational spectra the DFT calculations were combined with Pulay＇s scaled quantum mechanical force field （SQMFF） methodology in order to fit the theoretical Wavenumber values to the experimental ones. The characteristics of the electronic delocalization of all structures of both forms were performed by using natural bond orbital （NBO）, while the corresponding topological properties of electronic charge density are analysed by employing Bader＇s atoms in molecules theory （AIM）.

Synthesis,Structure and DFT Calculations of a Novel Copper(Ⅱ)Complex Based on Tert-butyl 2-[N-(tert-butyloxycarbonylmethyl)-2-picolyamino]acetate

A novel copper（Ⅱ） complex with tert-butyl 2-[N-（tert-butyloxycarbonylmethyl）-2-picolyamino]acetate（ampy） was synthesized and structurally characterized by elemental analysis, FT-IR spectrum, electrospray ionization-mass spectrometry, UV-vis spectrum and single-crystal X-ray diffraction, respectively. A mononuclear copper（II） complex with ampy, [Cu（ampy）Cl2]（1）, was formed irrespective of the metal-to-ligand molar ratios（[Cu2＋]：[ampy] = 0.5：1, 1：1, and 2：1） as a single product. Complex 1 crystallizes in the orthorhombic system, space group Pbca with a = 12.343（2）, b = 18.928（3）, c = 20.058（4） A, V = 4686.1（14） A3, Z = 8, Dc = 1.3349（4） g/cm3, F（000） = 1920, S = 1.016, R = 0.0693 and w R = 0.1721 for 3151 observed reflections with I 〉 2σ（I）. X-ray diffraction analysis reveals that the central copper（II） ion is bound by pyridyl N, tertiary amine N and carbonyl O atoms of the quadridentate ampy as well as two Cl anions, constructing a slightly distorted octahedral geometry. Complex 1 further constructs a stable 3D supramolecular architecture by intermolecular C–H…Cl hydrogen bonds. In addition, the molecular geometry was calculated by density functional theory（DFT/B3LYP） method with the basis sets（6-31＋G（d,p） for H, C, N, O and Cl atoms, and LANL2 DZ for Cu atom, respectively）. The calculated results show that the optimized geometrical parameters are in good agreement with the experimental data. Natural bond orbital（NBO） analysis and frontier molecular orbitals（FMOs） analysis were investigated at the same level.

Pseudo-Bonding Interaction between Boron-doped Heterofullerene and Zinc Porphine Predicted by DFT Calculation

Theoretical study on the supramolecular complexes formed between boron-doped het- erofullerene （C59B） and zinc porphine （ZnF）, namely C59B-ZnP and its anion species C59B-ZnP, was performed by density functional theory calculation at wB97XD/6-31G（d） level. Strong interaction between porphyrin and heterofullerene moiety was predicted for these complexes based on geometry and electronic structure analysis. Especially, pseudobonding interaction occurring between the B atom of fullerene and the N atom of porphyrin was predicted to occur in C59B-ZnP complex, but be broken in C59B-ZnP complex. Time-dependent density functional theory calculation manifests the redshift of electron absorption for ZnP upon the interaction with heterofullerene.

First Oxidation Product of Vitamin C, the Dehydro-L-Ascorbic Acid Dimer： A Study Based on FTIR-Raman and DFT Calculations

We studied the first oxidation product of vitamin C, the dehydro-L-ascorbic acid dimer and characterized it by infrared and Raman spectroscopies in the solid phase. The Density functional theory was used to study its structure and vibrational properties. These calculations gave us a precise knowledge of the normal modes of vibration taking into account that the molecule comprises a system of five fused rings; non planar γ-lactone and furonose rings are attached to a central dioxan ring in the twisted boat conformation. The calculated harmonic vibrational frequencies are consistent with the experimental vibrational spectra. An assignment of the observed spectral features is proposed. The shift of the band located in the infrared spectrum of the ascorbic acid from 3409 cm^-1 to 3299 cml and the remarkable increase in the band intensity at 1784 cm^-1 evidences the acid decomposition into its first product, the dehydro-L-ascorbic acid. The theoretical vibrational calculations allowed us to obtain a set of scaled force constants. The nature of the different -γ-lactone, furanose and dioxan rings and their topological properties were investigated by means of natural bond orbital and Bader＇s atoms in the molecule theory, respectively.

DFT calculation on relaxation and electronic structure of sulfide minerals surfaces in presence of H_2O molecule

First-principles calculations are performed to investigate the relaxation and electronic properties of sulfide minerals surfaces(MoS2, Sb2S3, Cu2 S, ZnS, PbS and FeS2) in presence of H2 O molecule. The calculated results show that the structure and electronic properties of sulfide minerals surfaces have been influenced in presence of H2 O molecule. The adsorption of the flotation reagent at the interface of mineral-water would be different from that of mineral surface due to the changes of surface structures and electronic properties caused by H2 O molecule. Hence, the influence of H2 O molecule on the reaction of flotation reagent with sulfide mineral surface will attract more attention.

Performance and mechanism of carbamazepine removal by FeS-S_(2)O_(8)^(2–)process:experimental investigation and DFT calculations

As persulfate(S_(2)O_(8)^(2-))is being increasingly used as an alternative oxidizing agent,developing lowcost and eco-friendly catalysts for efficient S_(2)O_(8)^(2-)activation is potentially useful for the treatment of wastewater containing refractory organic pollutant.In this study,the degradative features and mechanisms of carbamazepine(CBZ)were systematically investigated in a novel FeS-S_(2)O_(8)^(2-)process under near-neutral conditions.The results exhibited that CBZ can be effectively eliminated by the FeS-S_(2)O_(8)^(2-)process and the optimal conditions were:250 mg/L FeS,0.5 mmol/L S_(2)O_(8)^(2-),and pH=6.0.The existence of Cl^(−)(1 and 50 mmol/L)has little influence on the CBZ elimination,while both HCO_(3)^(−) and HPO_(4)^(2−)(1 and 50 mmol/L)significantly suppressed the CBZ removal in the FeS-S_(2)O_(8)^(2-)process.CBZ could be degraded via a radical mechanism in the FeS-S_(2)O_(8)^(2-)process,the working radical species(i.e.,SO_(4)•−and•OH)were efficiently formed via the promoted decomposition of S_(2)O_(8)^(2-)by the surface Fe2+on the FeS and the dissolved ferrous ions in solution.Based on the identified oxidized products and Fukui index calculations,a possible degradation pathway of CBZ was speculated.More importantly,a two-stage oxidation mechanism of CBZ elimination was speculated in the FeS-S_(2)O_(8)^(2-)process,the activation of S_(2)O_(8)^(2-)by the surface-active Fe(II)of FeS dominated in the initial 5 min,while homogeneous oxidation reactions played more essential parts than others in the following reaction stage(5–60 min).Overall,this study demonstrated that the FeS-S_(2)O_(8)^(2-)process is capable of removing CBZ from water efficiently.

Carbon-based single atom catalyst: Synthesis, characterization, DFT calculations

Carbon-based single-atom catalysts(SACs) with atomic sizes of active sites have become the promising candidates for a variety of catalytic systems because of their high atom utilization, and unique electronic structures. Different types of single-atom sites can be fabricated via multiple preparation strategies, which would demonstrate distinct different coordination configurations and electronic features, and ultimately affected the structure-catalysis relationship of SACs in targeted reactions. As a result, it is necessary to identify the active sites of SACs and understand the structure-catalysis relationship of SACs at the atomic scale. In this review, a variety of preparation strategies of carbon-based SACs were documented. Then, the recent development on versatile characterization techniques and computational achievements were summarized regarding in understanding the electronic and geometric characteristics of carbon-based SACs.Finally, major challenges and development directions concerning single-atom sites identification and advanced tools development are discussed to shed light on future research of carbon-based SACs.

Investigation of radionuclide ^(60)Co(Ⅱ) binding to TiO_2 by batch technique,surface complexation model and DFT calculations

The interaction between radionuclides and solid/water interfaces is important to understand the physicochemical processes of radionuclides in the natural environment.Herein,the interaction of 60Co(Ⅱ) with TiO 2 in aqueous solution as a function of pH and ionic strength was studied by using batch technique combined with surface complexation model and density functional theory(DFT) calculations.The batch experimental results showed that the adsorption of 60Co(Ⅱ) was dependent on pH and independent of ionic strength,indicating the formation of inner-sphere surface complexes on TiO 2 surfaces.The results of surface complexation models and DFT calculations indicated that the surface species of 60Co(Ⅱ) adsorbed on TiO 2 followed the trend:B structure(i.e.,60Co(Ⅱ) was linked to one bridge oxygen site) was the dominant surface species at low pH,and TT structure(i.e.,60Co(Ⅱ) was linked to two terminal oxygen sites) became the important surface complex at neutral and alkaline pH values.These results demonstrated that a multi-technique approach could lead to definitive information on the structures of adsorbed 60Co(Ⅱ) at the molecular level at the TiO 2 /water interfaces,as well as realistic models to rationalize and accurately evaluate the macroscopic manifestations of radionuclide adsorption phenomena.

Photoluminescence emissions of Ca_(1-x)WO_(4):xEu^(3+):Bridging between experiment and DFT calculations

In this work,the impact of the doping process on the photoluminescence emission of CaWO_(4) as a function of the concentration of Eu^(3+) cation(0.01 mol%,0.02 mol%,0.04 mol%,0.06 mol%,0.08 mol%,and 0.10 mol%) is discussed in detail.Ca_(1-x)WO~4:xEu^(3+) samples were successfully synthesized by a simple coprecipitation method followed by microwave irradiation.The blue shift in the absorption edge confirms the quantum confinement effect and the band gap energy covers the range from 3.91 to 4.18 eV,as the amount of Eu^(3+) cations increases.The experimental results are sustained by first-principles calculations,at the density functional theory level,to decipher the geometry and electronic properties,thereby enabling a more accurate and direct comparison between theory and experiment for the Ca_(1-x)WO_(4):xEu^(3+) structure.

Analysis of the electronic structures of 3d transition metals doped CuGaS_2based on DFT calculations

3d transition metals doped CuGaS2 are considered as possible absorbing material candidates for intermediated band thin film solar cells. The electronic structure and optical properties of 3d transition metals doped CuGaS2 are investigated by using density functional theory calculations with the GGA ＋ U method in the present work. The doping with 3d transition metals does not obviously change the crystal structure, band gap, and optical absorption edge of the CuGaS2 host. However, in the case of CuGa1-χTMχS2 （TM = Ti, V, Cr, Fe, and Ni）, there is at least one distinct isolated impurity energy level in the band gap, and the optical absorption is enhanced in the ultraviolet-light region. Therefore, these materials are band thin film solar ceils. The calculated results are very well better explain them. ideal absorber material candidates for intermediated consistent with experimental observations, and could better explain them.

DFT calculation analysis of oxygen reduction activity and stability of bimetallic catalysts with Pt-segregated surface

The stability and oxygen reduction reaction （ORR） activity of the Pt-segregated surface in various Pt-M alloys （M： transition metals） are investigated through systematic DFT calculations on the thermodynamic （alloy formation energy and Pt surface segregation energy）, surface chemical property （oxygen binding energy） and electronic （d-band center） properties. Factors af- fecting these properties, such as the atomic radii and surface energy of M and the electronic ligand interaction between Pt and M are analyzed as a function of outmost d electron numbers of M. It is shown that the electronic ligand interaction plays de- termining role in the alloy formation energy of various Pt-M alloys; the formation of Pt-segregated surface in Pt-M alloys is faw）red when alloying metals have higher surface energy and smaller radii than Pt; the oxygen binding energy on the Pt-segregated surface in Pt-M alloys varies approximately linearly with the d-band center of surface Pt atoms; the lattice strain and electronic ligand effects are simply additive in Pt-M alloys; the stain effect in Pt-M alloys nearly linearly affects the d-band center of the Pt-segregated surface in Pt-M alloys; transition metals with less than 10 d electrons mostly exhibit electron ligand effects which result in downshift of the d-band center of the segregated surface Pt atoms, while those with ten d electrons exhibit electron ligand effect upshifting the d-band center of the segregated Pt atoms.

High active amorphous Co(OH)_(2) nanocages as peroxymonosulfate activator for boosting acetaminophen degradation and DFT calculation

Acetaminophen(ACE)is commonly used in analgesic and antipyretic drug,which is hardly removed by traditional wastewater treatment processes.Herein,amorphous Co(OH)_(2)nanocages were explored as peroxymonosulfate(PMS)activator for efficient degradation of ACE.In the presence of amorphous Co(OH)_(2)nanocages,100%of ACE removal was reached within 2 min with a reaction rate constant k_(1)=3.68 min 1 at optimum pH 5,which was much better than that of crystallineβ-Co(OH)_(2)and Co_(3)O_(4).Amorphous materials(disorder atom arrangement)with hollow structures possess large specific surface area,more reactive sites,and abundant vacancies structures,which could efficiently facilitate the catalytic redox reactions.The radicals quenching experiment demonstrated that SO_(4)^(·-)radicals dominated the ACE degradation rather than^(·)OH radicals.The mechanism of ACE degradation was elucidated by the an alysis of degradation in termediates and theoretical calculation,indicating that the electrophilic SO_(4)^(·-)and^(·)OH tend to attack the atoms of ACE with high Fukui index(f).Our finding highlights the remarkable advantages of amorphous materials as heterogeneous catalysts in sulfate radicals-based AOPs and sheds new lights on water treatment for the degradation of emerging organic contaminants.

Synthesis,Crystal Structure and DFT Calculation of 2-Methoxyimino Phenylacetate Derivatives Containing 1,3,4-Oxadiazole Ring

Four novel 2-methoxyimino phenylacetate derivatives containing 1,3,4-oxadiazole ring were designed and synthesized from the key intermediate of Trifloxystrobin or Azoxystrobin via intermediate derivatization and active structure splicing.The chemical structures of the target compounds were confirmed by]H NMR,13C NMR and elemental analysis.The crystal structure of methyl(E)-2-(methoxyimino)-2-(2-(((5-((4-methoxyphenoxy)methyl)-1,3,4-oxadiazol-2-yl)thio)methyl)phenyl)acetate(Al)was determined by single-crystal X-ray diffraction.Compound A1 belongs to triclinic system,space group Pi with two molecules in each unit cell.The benzene ring plane C(2)-C(3)-C(4)-C(5)-C(6)-C(7)and oxazole ring plane are nearly parallel with the dihedral angle of 6.4°.The benzene ring plane C(12)-C(13)-C(14)-C(15)-C(16)-C(17)and oxazole ring plane are not perpendicular with the dihedral angle of 49.4°.The crystal of compound Al is stabilized by π-π stacking interactions.The fungicidal activities of the target compounds against four plant pathogenic fungi in vitro were tested,and some of them had good activities.The DFT calculation was carried out to study the structure-activity relationship of the title derivatives using Gasian 09 and Multiwfii 3.6.

New luminescent cyclometalated iridium(Ⅲ) complexes containing fluorinated phenylisoquinoline-based ligands: Synthesis, structures,photophysical properties and DFT calculations

Two new fluorinated phenylisoquinoline-based iridium（Ⅲ） complexes,[Ir（f2piq）2（bipy）][PF6]（3a） and[Ir（fmpiq）2（bipy）][PF6]（3b）（f2piq = l-（2,4-difluorophenyl）isoquinoline,fmpiq = 1-（4-fluoro-2-methylphenyl）isoquinoline,bipy = 2,2＇-bipyridine）,have been synthesized and fully characterized.Single crystal X-ray diffraction study has been undertaken on complexes 3a and 3b,which show that each adopts the distorted octahedral coordination geometry with the cis-C,C＇ and trans-N,N＇ configuration.The photoluminescence spectra of 3a and 3b exhibit yellow and orange emission maxima at 584 and 600 nm,respectively.The frontier molecular orbital diagrams and the lowest-energy electronic transitions of 3a-3b have been calculated with density functional theory（DFT） and time-dependent DFT（TD-DFT）.The absorption and emission spectra of complex 3b is red-shifted relative to those of complex 3a,as a consequence of the nature of the methyl group.

Cation-induced assembly of Zn(Ⅱ),Cd(Ⅱ) and Hg(Ⅱ) coordination complexes and DFT calculations to evaluate weak interactions between the helical chains

Two new coordination polymers [ZnLI2]∞ （1） and [CdLI2]∞ （2） （L： 3,6-di-（1,2,4-triazole-l-yl）-N-hexylcarbazole） were syn- thesized and their crystal structures were determined by single-crystal X-ray diffraction techniques. Complexes are both constructed with the helical chains along the 2l screw axis. The coordination bond, C-H...I weak interactions and π-π interactions play significant roles in constructing their 3D or 2D frameworks. Two different DFT calculations are performed for the weak interactions between the helical chains of the three different coordination polymers （[ZnLI2]∞[CdLI2]∞, and the reported [HgLI2]∞）. The results reveal that weak interactions play important roles in these supramolecular systems of helical configuration, namely, the trend is the shorter H…I distance and π-π stacking distance, the stronger the intermolecular interactions. The photoluminescence of the complexes measured in the solid state at room temperature indicates that the emission intensity varies extensively, which can be rationalized by the heavy atom effect. helical configuration, weak interactions, DFT calculations, photoluminescence

Intramolecular α-Oxygenation of Amines via N-Heterocyclic Carbene-Catalyzed Domino Reaction of Aryl Aldehyde: Experiment and DFT Calculation

We have developed an N-heterocyclic carbene(NHC)-catalyzed domino reaction with aryl alde-hyde through a simple acyl azolium intermediate using phenyliodine(III)diacetate(PIDA)as an oxi-dant.Controlled experiments and density functional theory calculations supported a domino two-stage mechanism from aldehyde/amine to anα-oxygen-ation product,including NHC-catalyzed oxidation of the aldehyde to carboxylic acid via acyl azolium intermediate,and further,an addition of carboxyl-ate to iminium intermediate.Our study reveals a new model for the oxidation of Breslow intermedi-ate via electrophilic attack of the hydroxyl group by PIDA.

DFT calculation on p-xylene sensing mechanism of (C_(4)H_(9)NH_(3))_(2)PbI_(4) single crystal based on physisorption

P-xylene(p-C_(8)H_(10))is extremely harmful and dangerous to human health due to high toxicity and strong carcinogenicity.Exploring sensitive material to effectively detect p-xylene is of importance.In this paper,perovskite single crystal(C_(4)H_(9)NH_(3))_(2)PbI_(4) has been successfully synthesized via solution method.The obtained product was analyzed by single crystal X-ray diffraction.With the space group Pbca,orthorhombic(C_(4)H_(9)NH_(3))_(2)PbI_(4) layered perovskite structure consists of an extended two-dimensional network of corner-sharing PbI_(6) octahedron.Single layer perovskite sheets of distorted PbI_(6) octahedron alternated with protonated n-butylammonium cation bilayers,which offers many advantages and provides the possibility of forming a gas sensor device based on the change of resistances.Density functional theory(DFT)simulations regarding the adsorption energy revealed that this organicinorganic hybrid perovskite compound has excellent selectivity toward p-xylene compared with other gases including C_(2)H_(5)OH,C_(6)H_(6),CH_(2)Cl_(2),HCHO,CH_(3)COCH_(3) and C_(7)H_(8).The calculation of electron density,density of states and electron density difference showed the sensing mechanism of p-C_(8)H_(10) is mainly derived from physical adsorption-desorption in view of electron transfer.