scholarly journals Theoretical study of lumichrome, 1-methyl-lumichrome and lumiflavin binding ability with thymine

2021 ◽  
Vol 14 (1) ◽  
pp. 7-13
Author(s):  
Denisa Cagardová ◽  
Martin Michalík ◽  
Vladimír Lukeš
Keyword(s):  
Hydrogen Bonds ◽  
Density Functional ◽  
Fluorescence Spectra ◽  
Photophysical Properties ◽  
Theoretical Data ◽  
Binding Ability ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Electronic Ground ◽  
Experimental Absorption

Abstract Gas-phase geometry and electronic structure of lumichrome, 1-methyl-lumichrome and lumiflavin in the electronic ground state and their excited states were investigated using the Density Functional Theory. Their binding ability with thymine was estimated for model van der Waals dimers with two intermolecular hydrogen bonds. The influence of hydrogen bonds on their photophysical properties was analyzed. Obtained theoretical data were compared with available experimental absorption and fluorescence spectra.

A combined study of the equation of state of monazite-type lanthanum orthovanadate usingin situhigh-pressure diffraction andab initiocalculations

2014 ◽  
Vol 70 (3) ◽  
pp. 533-538 ◽  
Author(s):  
Olga Ermakova ◽  
Javier López-Solano ◽  
Roman Minikayev ◽  
Stefan Carlson ◽  
Agata Kamińska ◽  
...  
Keyword(s):  
Equation Of State ◽  
Density Functional ◽  
Room Temperature ◽  
Theoretical Data ◽  
Perfect Agreement ◽  
Functional Theory ◽  
Compression Direction ◽  
The Density Functional Theory ◽  
Murnaghan Equation

Lanthanum orthovanadate (LaVO4) is the only stable monazite-type rare-earth orthovanadate. In the present paper the equation of state of LaVO4is studied usingin situhigh-pressure powder diffraction at room temperature, andab initiocalculations within the framework of the density functional theory. The parameters of a second-order Birch–Murnaghan equation of state,i.e.those fitted to the experimental and theoretical data, are found to be in perfect agreement – in particular, the bulk moduli are almost identical, with values of 106 (1) and 105.8 (5) GPa, respectively. In agreement with recent reported experimental data, the compression is shown to be anisotropic. Its nature is comparable to that of some other monazite-type compounds. The softest compression direction is determined.

The impact of cation–π, anion–π, and CH–π interactions on the excited-state intramolecular proton transfer of 1,4-dihydroxyanthraquinone

2021 ◽  
Author(s):  
Asiyeh Shahraki ◽  
Ali Ebrahimi ◽  
Shiva Rezazadeh ◽  
Roya Behazin
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Photophysical Properties ◽  
Intramolecular Proton Transfer ◽  
Time Dependent ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
The Impact ◽  
Dependent Density

The impact of ion-π interactions on the photophysical properties of quinizarin have been investigated using the density functional theory and time-dependent density functional theory at the M06-2X/6-311++G(d,p) level in the gas phase and solution.

First-principles study on structural, elastic and thermal properties of γ-TiAl and α2-Ti3Al phases in TiAl-based alloy under high pressure

2017 ◽  
Vol 31 (11) ◽  
pp. 1750079 ◽  
Author(s):  
Chaoyan Zhang ◽  
Hua Hou ◽  
Yuhong Zhao ◽  
Xiaomin Yang ◽  
Yaqiong Guo
Keyword(s):  
High Pressure ◽  
Thermal Properties ◽  
Density Functional ◽  
Theoretical Data ◽  
Debye Model ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Two Phases ◽  
Calculated Equilibrium ◽  
Good Agreement

The structural, elastic and thermal properties of [Formula: see text]-TiAl and [Formula: see text]-Ti3Al phases in the TiAl-based alloy under pressure were reported using CASTEP program based on the density functional theory. The calculated equilibrium parameters and elastic constants are in good agreement with experimental and the available theoretical data. The results indicate that under the same pressure, the [Formula: see text] phase in the direction along [Formula: see text]-axis is easier to be compressed than the [Formula: see text] phase, while the compression along [Formula: see text]-axis of [Formula: see text] phase is larger than that of [Formula: see text] phase; when the pressure is below 20 GPa, both the two phases are elastically stable, but the [Formula: see text] phase have higher shear modulus and Young’s modulus, and the [Formula: see text] phase has better ductility and plasticity. Debye temperature, bulk modulus, thermal expansion coefficient and heat capacity of the [Formula: see text] phase and [Formula: see text] phase under high pressure and high temperature were also successfully calculated and compared using the quasi-harmonic Debye model in the present work.

Computational insights into the photophysical and electroluminescence properties of homoleptic fac-Ir(C^N)3 complexes employing different phenyl-derivative-featuring phenylimidazole-based ligands for promising phosphors in OLEDs

2016 ◽  
Vol 45 (7) ◽  
pp. 3034-3047 ◽  
Author(s):  
Jieqiong Li ◽  
Li Wang ◽  
Kenan Sun ◽  
Jinglai Zhang
Keyword(s):  
Density Functional Theory ◽  
Electronic Structures ◽  
Density Functional ◽  
Photophysical Properties ◽  
Density Functional Theory Method ◽  
Theory Method ◽  
Functional Theory ◽  
Phenyl Derivative ◽  
The Density Functional Theory

The electronic structures and photophysical properties of three homoleptic iridium(iii) complexes IrL3 with C^N ligands are investigated by means of the density functional theory method.

scholarly journals Photophysical Properties of Nitrated and Halogenated Phosphorus Tritolylcorrole Complexes: Insights from Theory

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2779 ◽  
Author(s):  
Marta Alberto ◽  
Bruna De Simone ◽  
Gloria Mazzone ◽  
Nino Russo ◽  
Marirosa Toscano
Keyword(s):  
Excited States ◽  
Density Functional ◽  
Energy Gap ◽  
Photophysical Properties ◽  
Intersystem Crossing ◽  
Triplet States ◽  
Excited Singlet ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Singlet And Triplet States

The photophysical properties of a series of nitrated and halogenated phosphorus tritolylcorrole complexes were studied in dichloromethane solvent by using the density functional theory. Particular emphasis was given to the absorption spectra, the energy gap between the excited singlet and triplet states, and the magnitude of the spin-orbit couplings for a series of possible intersystem crossing channels between those excited states. The proposed study provides a better description of the photophysical properties of these systems while giving insights into their possible use as photosensitizers in photodynamic therapy.

Study of first principles on anisotropy and elastic constants of YAl3 compound

2020 ◽  
Vol 98 (4) ◽  
pp. 357-363
Author(s):  
Tahsin Özer
Keyword(s):  
Elastic Constants ◽  
First Principles ◽  
Density Functional ◽  
Theoretical Data ◽  
Anisotropic Behavior ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
The Density Functional Theory ◽  
Quantum Espresso

Using the density functional theory (DFT) calculations, the structural optimization of the YAl3 compound was performed on the generalized gradient approximation (GGA) with quantum ESPRESSO (QE) software. Elastic constants were calculated after the optimization process. Polycrystalline quantities, such as bulk and shear modulus, Young’s modulus, and Poisson’s ratio, were determined using calculated elastic constants. The anisotropy of the compound was studied in detail. As a result of the calculations made, it was observed that the YAl3 compound exhibited mechanically stable structure and anisotropic behavior. In the ht2-YAl3 phase, the effect of pressure on physical properties was investigated in detail. The obtained results were compared with the existing experimental and other theoretical data.

scholarly journals Theoretical perspective on the electronic structure and photophysical properties for a series of mixed-carbene tris-cyclometalated iridium(iii) complexes

RSC Advances ◽  
2020 ◽  
Vol 10 (31) ◽  
pp. 18519-18525
Author(s):  
Jiawei Li ◽  
Deming Han ◽  
Jing Gao ◽  
Tong Chen ◽  
Bao Wang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Photophysical Properties ◽  
Theoretical Perspective ◽  
Time Dependent ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Dependent Density

The electronic structure and photophysical properties of four tris-cyclometalated iridium(iii) complexes have been theoretically investigated by the density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods.

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

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Denisa Cagardová ◽  
Jan Truksa ◽  
Martin Michalík ◽  
Jan Richtár ◽  
Jozef Krajčovič ◽  
...  
Keyword(s):  
Density Functional ◽  
Optical Transition ◽  
Photophysical Properties ◽  
Energy Levels ◽  
Dft Method ◽  
Functional Theory ◽  
Transition Energies ◽  
The Density Functional Theory ◽  
Td Dft

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.

scholarly journals Weak interactions of COVID-19 virus Mpro and peptide-like inhibitor N3: revealing the role of non-conventional hydrogen bonds by theoretical methods

2020 ◽  
Author(s):  
Ponciano García-Gutiérrez ◽  
Rafael A. Zubillaga ◽  
Ilich A. Ibarra ◽  
Ana Martínez ◽  
Rubicelia Vargas ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Density Functional ◽  
Weak Interactions ◽  
New Drugs ◽  
Functional Theory ◽  
Action Mechanisms ◽  
Main Protease ◽  
The Density Functional Theory ◽  
Non Covalent Interactions

Abstract Two models consisting of 469 atoms each one, for the interaction between the N3 inhibitor and the main protease of SARS-CoV (SARS-CoV Mpro) and SARS-CoV-2 (SARS-CoV-2 Mpro) viruses, were used to reveal by quantum chemistry methods the non-covalent interactions involved in these systems. Through the Density Functional Theory and the Quantum Theory of Atoms in Molecules the main conclusion reached by this study indicates that C-H· · ·O and C-H· · ·H hydrogen bonds are crucial to describe attractive interactions in these complexes. In general, these contacts are overlooked in many studies. However, these non-conventional hydrogen bonds represent more than a half of the energy interaction estimated for non-covalent contacts. These results are quite important for the design of new drugs since these interactions could drive the action mechanisms against these viruses. Hydrogen bonds are crucial to describe correctly the interactions between inhibitors and the main proteases.

Crystal structures of ammonium citrates

2018 ◽  
Vol 34 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Austin M. Wheatley ◽  
James A. Kaduk
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Crystal Structures ◽  
Density Functional ◽  
Hydroxyl Group ◽  
Powder Diffraction File ◽  
Functional Theory ◽  
Overlap Population ◽  
The Density Functional Theory

The crystal structures of (NH4)H2C6H5O7 and (NH4)3C6H5O7 have been determined using a combination of powder and single crystal techniques. The structure of (NH4)2HC6H5O7 has been determined previously by single crystal diffraction. All three structures were optimized using density functional techniques. The crystal structures are dominated by N-H⋅⋅⋅O hydrogen bonds, though O-H⋅⋅⋅O hydrogen bonds are also important. In (NH4)H2C6H5O7 very strong centrosymmetric charge-assisted O-H-O hydrogen bonds link one end of the citrate into chains along the b-axis. A more-normal O-H⋅⋅⋅O hydrogen bond links the other end of the citrate to the central ionized carboxyl group. In (NH4)2HC6H5O7, the very strong centrosymmetric O-H-O hydrogen bonds link the citrates into zig-zag chains along the b-axis. The citrates occupy layers parallel to the bc plane, and the ammonium ions link the layers through N-H⋅⋅⋅O hydrogen bonds. In (NH4)3C6H5O7, the hydroxyl group forms a hydrogen bond to a terminal carboxylate, and there is an extensive array of N-H⋅⋅⋅O hydrogen bonds. The energies of the density functional theory-optimized structures lead to a correlation between the energy of an N-H⋅⋅⋅O hydrogen bond and the Mulliken overlap population: E(N-H⋅⋅⋅O) (kcal/mole) = 23.1(overlap)½. Powder patterns of (NH4)H2C6H5O7 and (NH4)3C6H5O7 have been submitted to International Centre for Diffraction Data for inclusion in the powder diffraction file.

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