Theoretical modeling of optical spectra of N(1) and N(10) substituted lumichrome derivatives

AbstractA systematic study of (7,8-dimethylated) alloxazine, isoalloxazine, and their derivatives with substituted N(1) and N(10) positions was conducted using the density functional theory. The main aim of this work was the direct investigation of substituent effect on the molecular structure. Furthermore, HOMED aromaticity indices were calculated to describe the scope of the geometry changes. Frontier molecular orbitals of reference alloxazine, isoalloxazine and lumichrome derivatives were discussed by means of changes in their shape and energy levels. Photophysical properties were analyzed by determination of optical transition energies using the TD-DFT method. Obtained results were compared with previously published experimental data.

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DFT-PCM STUDIES OF THE SOLVENT EFFECTS ON THE ABSORPTION PROPERTIES OF DCM

Journal of Theoretical and Computational Chemistry ◽

10.1142/s0219633606002672 ◽

2006 ◽

Vol 05 (04) ◽

pp. 957-965 ◽

Cited By ~ 1

Author(s):

BO-CHENG WANG ◽

CHIN-KUEN TAI

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Solvent Polarity ◽

Dft Method ◽

Polarizable Continuum Model ◽

Maximum Absorption ◽

Functional Theory ◽

The Density Functional Theory ◽

Td Dft ◽

Solvent Environment

In this paper, we have performed the optimized structures of the red emitting material, 4-(dicyanomethylene)-2-methyl-6-[p-(dimethyl amino) styryl]-4H-pyran (DCM), with different polarity solvent environments by using the density functional theory (DFT) method, B3LYP/6-31G*. The time-dependent density functional theory (TD-DFT) and the polarizable continuum model (PCM) have been used to obtain the optical properties in the solvent environment. It has been observed that when the solvent polarity increases, the DCM molecule exhibits the red shift in the maximum absorption wavelength [Formula: see text] and enhances the oscillator strength (f). The solvent polarity also enhances the electron transfer ability from the electron-donating dimethylamine group (-N(CH3)2) to the electron-withdrawing =C(CN)2 group. The S 0 → S 1 transition of DCM is found to be π–π*. The maximum absorption wavelengths [Formula: see text] of different solvent environments are found to be consistent with the reported experimental results.

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Photophysical Properties of N-Methyl and N-Acetyl Substituted Alloxazine: A Theoretical Investigation

Physical Chemistry Chemical Physics ◽

10.1039/d1cp01201k ◽

2021 ◽

Author(s):

Huimin Guo ◽

Xiaolin Ma ◽

Zhiwen Lei ◽

Yang Qiu ◽

Bernhard Dick ◽

...

Keyword(s):

Density Functional Theory ◽

Electronic Structure ◽

Theoretical Investigation ◽

Density Functional ◽

Photophysical Properties ◽

Time Dependent ◽

Functional Theory ◽

Td Dft ◽

Dependent Density

The electronic structure and photophysical properties of a series of N-Methyl and N-Acetyl substituted alloxazine (AZs) were investigated with extensive density functional theory (DFT) and time-dependent density functional theory (TD-DFT)...

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First principles analysis of oxygen vacancy formation and migration in Sr2BMoO6 (B = Mg, Co, Ni)

RSC Advances ◽

10.1039/c6ra02297a ◽

2016 ◽

Vol 6 (38) ◽

pp. 31968-31975 ◽

Cited By ~ 9

Author(s):

Shuai Zhao ◽

Liguo Gao ◽

Chunfeng Lan ◽

Shyam S. Pandey ◽

Shuzi Hayase ◽

...

Keyword(s):

Density Functional Theory ◽

Oxygen Vacancy ◽

First Principles ◽

Density Functional ◽

Dft Method ◽

Double Perovskites ◽

Functional Theory ◽

Oxygen Vacancy Formation ◽

The Density Functional Theory ◽

And Migration

In this work, we present a detailed first-principles investigation on the stoichiometric and oxygen-deficient structures of double perovskites, Sr2BMoO6 (B = Mg, Co and Ni), using the density functional theory (DFT) method.

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Vibrational Study and Force Field of the Citric Acid Dimer Based on the SQM Methodology

Advances in Physical Chemistry ◽

10.1155/2011/347072 ◽

2011 ◽

Vol 2011 ◽

pp. 1-10 ◽

Cited By ~ 43

Author(s):

Laura Cecilia Bichara ◽

Hernán Enrique Lanús ◽

Evelina Gloria Ferrer ◽

Mónica Beatriz Gramajo ◽

Silvia Antonia Brandán

Keyword(s):

Citric Acid ◽

Force Field ◽

Density Functional ◽

Solid Phase ◽

Dft Method ◽

Electronic Charge ◽

Functional Theory ◽

The Density Functional Theory ◽

Atoms In Molecules Theory ◽

Best Fit

We have carried out a structural and vibrational theoretical study for the citric acid dimer. The Density Functional Theory (DFT) method with the B3LYP/6-31G∗ and B3LYP/6-311++ methods have been used to study its structure and vibrational properties. Then, in order to get a good assignment of the IR and Raman spectra in solid phase of dimer, the best fit possible between the calculated and recorded frequencies was carry out and the force fields were scaled using the Scaled Quantum Mechanic Force Field (SQMFF) methodology. An assignment of the observed spectral features is proposed. A band of medium intensity at 1242 together with a group of weak bands, previously not assigned to the monomer, was in this case assigned to the dimer. Furthermore, the analysis of the Natural Bond Orbitals (NBOs) and the topological properties of electronic charge density by employing Bader's Atoms in Molecules theory (AIM) for the dimer were carried out to study the charge transference interactions of the compound.

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Chloroquine drug and Graphene complex for treatment of COVID-19

10.21203/rs.3.rs-29418/v1 ◽

2020 ◽

Author(s):

Saeedeh Mohammadi ◽

Mohammad Esmailpour ◽

Mina Mohammadi

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Energy Gap ◽

Dft Method ◽

Complex State ◽

Functional Theory ◽

The Density Functional Theory ◽

Structural And Electrical Properties ◽

Suitable Structure ◽

Drug Complex

Abstract This paper is a new step in helping the treatment of coronavirus by improving the performance of chloroquine drug. For this purpose, we propose a complex of chloroquine drug with graphene nanoribbon (GNR) scheme. We compute the structural and electrical properties and absorption of chloroquine (C18H26ClN3) and GNR complex using the density functional theory (DFT) method. By creating a drug and GNR complex, the density of states of electrons increases and the energy gap decreases compared to the chloroquine. Also, using absorption calculations and spectrums such as infrared and UV-Vis spectra, we showed that GNR is a suitable structure for creating chloroquine drug complex. Our results show that the dipole moment, global softness and electrophilicity for the drug complex increases compared to the non-complex state. Our calculations can be useful for increasing performance and reducing the side effects of chloroquine, and thus can be effective in treating coronavirus.

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Theoretical Investigation of Energetic Salts with Pentazolate Anion

Molecules ◽

10.3390/molecules25081783 ◽

2020 ◽

Vol 25 (8) ◽

pp. 1783

Author(s):

Hao-Ran Wang ◽

Chong Zhang ◽

Bing-Cheng Hu ◽

Xue-Hai Ju

Keyword(s):

Density Functional ◽

Dft Method ◽

Functional Theory ◽

Calculated Density ◽

The Density Functional Theory ◽

Energetic Salts ◽

Vertical Electron Affinity ◽

The Difference ◽

Nitrogen Contents ◽

Experimental Density

Energetic salts based on pentazolate anion (cyclo-N5−) have attracted much attention due to their high nitrogen contents. However, it is an enormous challenge to efficiently screen out an appropriate cation that can match well with cyclo-N5−. The vertical electron affinity (VEA) of the cations and vertical ionization potential (VIP) of the anions for 135 energetic salts and some cyclo-N5− salts were calculated by the density functional theory (DFT). The magnitudes of VEA and VIP, and their matchability were analyzed. The results based on the calculations at the B3LYP/6-311++G(d,p) and B3LYP/aug-cc-pVTZ levels indicate that there is an excellent compatibility between cyclo-N5− and cation when the difference between the VEA of cation and the VIP of cyclo-N5− anion is −2.8 to −1.0 eV. The densities of the salts were predicted by the DFT method. Relationship between the calculated density and the experimental density was established as ρExpt = 1.111ρcal − 0.06067 with a correlation coefficient of 0.905. This regression equation could be in turn used to calibrate the calculated density of the cyclo-N5− energetic salts accurately. This work provides a favorable way to explore the energetic salts with excellent performance based on cyclo-N5−.

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First-Principles Determination of the Polarizabilities of Carbon Tubules as a Function of Length

MRS Proceedings ◽

10.1557/proc-349-241 ◽

1994 ◽

Vol 349 ◽

Cited By ~ 2

Author(s):

Andrew A. Quong ◽

Mark R. Pederson

Keyword(s):

First Principles ◽

Density Functional ◽

Valence Electron ◽

Local Density ◽

Density Approximation ◽

Functional Theory ◽

Size Dependent ◽

The Density Functional Theory ◽

Linear And Nonlinear

ABSTRACTWe use the local-density-approximation to the density-functional theory to determine the axial polarizabilities of fullerene tubules as a function of length and winding topologies. Specifically, we present linear polarizabilities for tubules of composition C12H24, C36H24, C40H20 and C60H24. The size-dependent variation in the dipole-coupled gaps between pairs of occupied and unoccupied levels leads to enhancements in the polarizability per valence electron as the length of the tubule increases. The results are compared to recent densityfunctional based calculations of the linear and nonlinear polarizabilities for fullerene and benzene molecules.

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Theoretical Calculations on the Mechanism of Enantioselective Copper(I)-Catalyzed Addition of Enynes to Ketones

Catalysts ◽

10.3390/catal8090359 ◽

2018 ◽

Vol 8 (9) ◽

pp. 359 ◽

Cited By ~ 1

Author(s):

Hanwei Li ◽

Mingliang Luo ◽

Guohong Tao ◽

Song Qin

Keyword(s):

Density Functional Theory ◽

Steric Hindrance ◽

Phenyl Ring ◽

Density Functional ◽

Theoretical Calculations ◽

Dft Method ◽

Catalytic Cycle ◽

Functional Theory ◽

The Density Functional Theory ◽

Chiral Systems

Computational investigations on the bisphospholanoethane (BPE)-ligated Cu-catalyzed enantioselective addition of enynes to ketones were performed with the density functional theory (DFT) method. Two BPE-mesitylcopper (CuMes) catalysts, BPE-CuMes and (S,S)-Ph-BPE–CuMes, were employed to probe the reaction mechanism with the emphasis on stereoselectivity. The calculations on the BPE-CuMes system indicate that the active metallized enyne intermediate acts as the catalyst for the catalytic cycle. The catalytic cycle involves two steps: (1) ketone addition to the alkene moiety of the metallized enyne; and (2) metallization of the enyne followed by the release of product with the recovery of the active metallized enyne intermediate. The first step accounts for the distribution of the products, and therefore is the stereo-controlling step in chiral systems. In the chiral (S,S)-Ph-BPE–CuMes system, the steric hindrance is vital for the distribution of products and responsible for the stereoselectivity of this reaction. The steric hindrance between the phenyl ring of the two substrates and groups at the chiral centers in the ligand skeleton is identified as the original of the stereoselectivity for the titled reaction.

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Effect of Nitrogen Cation as “Electron Trap” at π-Linker on Properties for p-Type Photosensitizers: DFT Study

Molecules ◽

10.3390/molecules24173134 ◽

2019 ◽

Vol 24 (17) ◽

pp. 3134 ◽

Cited By ~ 2

Author(s):

Zhi-Dan Sun ◽

Jiang-Shan Zhao ◽

Xue-Hai Ju ◽

Qi-Ying Xia

Keyword(s):

Driving Force ◽

Density Functional ◽

Electron Trap ◽

Hole Injection ◽

Functional Theory ◽

The Density Functional Theory ◽

Td Dft ◽

Harvesting Efficiency ◽

Light Harvesting Efficiency ◽

P Type

On the basis of thieno(3,2-b)thiophene and dithieno[3,2-b:2′,3′-d]thiophene (T2 and T3 moieties) as π-linker, the A, D and S series dyes were designed to investigate the effect of the introducing N+ as an “electron trap” into T2 and T3 on the properties of the dyes. The optimized structures, electronic and optical properties were investigated by the density functional theory (DFT) and time-dependent DFT (TD-DFT). The results show that the properties of the dyes are sensitive to the N+ position in π-linkers. D series dyes with electron-withdrawing units located near the donor have better properties than the corresponding A series with the electron-withdrawing units located near the acceptor. For A and D series, the N+ modified dye named T2N+1-d displays the largest red shift of the UV–vis absorption, the maximum integral values of the adsorption-wavelength curves over the visible light, the highest light harvesting efficiency (LHE, 0.996), and the strongest adsorption energy (−44.33 kcal/mol). T2N+1-d also has a large driving force of hole injection (ΔGinj, −0.74 eV), which results in a more efficient hole injection. Bearing a lengthier π-linker than T2N+1-d, the properties of T2N+1-s are further improved. T2N+1-d moiety or its increased conjugated derivatives may be a promising π-linker.

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DFT Studies on the Antioxidant Activity of Naringenin and Its Derivatives: Effects of the Substituents at C3

International Journal of Molecular Sciences ◽

10.3390/ijms20061450 ◽

2019 ◽

Vol 20 (6) ◽

pp. 1450 ◽

Cited By ~ 3

Author(s):

Yan-Zhen Zheng ◽

Geng Deng ◽

Rui Guo ◽

Da-Fu Chen ◽

Zhong-Min Fu

Keyword(s):

Antioxidant Activity ◽

Density Functional ◽

Radical Scavenging Activity ◽

Resonance Effect ◽

Antioxidant Properties ◽

Radical Scavenging ◽

Dft Method ◽

Functional Theory ◽

The Density Functional Theory ◽

Selection Of

The radical scavenging activity of a flavonoid is largely influenced by its structure. The effects of the substituents at C3 position on the antioxidant activity of naringenin were carried out using the density functional theory (DFT) method. The reaction enthalpies related with the three well-established mechanisms were analyzed. Excellent correlations were found between the reaction enthalpies and Hammett sigma constants. Equations obtained from the linear regression can be helpful in the selection of suitable candidates for the synthesis of novel naringenin derivatives with enhanced antioxidant properties. In the gas and benzene phases, the antioxidant activity of naringenin was enhanced by the electron-donating substituents via weakening the bond dissociation enthalpy (BDE). In the water phase, it was strengthened by electron-withdrawing groups—via lowering the proton affinity (PA). The electronic effect of the substituent on the BDE of naringenin is mainly governed by the resonance effect, while that on the ionization potential (IP) and PA of naringenin is mainly controlled by the field/inductive effect.

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