scholarly journals Density Functional Theory Calculation of Molecular Descriptors for Simple Coumarins in Gas and Different Solvents

2020 ◽  
Vol 32 (10) ◽  
pp. 2545-2552
Author(s):  
Poodari Sumalatha ◽  
Mannam Subbarao
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Energy Gap ◽  
Theoretical Calculations ◽  
Density Functional Theory Calculation ◽  
Log P ◽  
Full Geometry Optimization ◽  
Functional Theory ◽  
Functional Density Theory

The primary aim of this study is to show the importance of molecular structure analysis of pharmaceutical active coumarins compounds using quantum chemistry methods based on density functional theory. To explore the theoretical calculations for global descriptors, the standard Gaussian 09W program was used for coumarins compounds. The full geometry optimization was carried out by the B3LYP/6-311G level of theory. The octanol-water and air-water partition coefficients were also estimated using functional density theory. The order of the HOMO-LUMO energy gap for studied coumarins in the gas phase is umbelliferone (UBA) < (herniarin) HNR ~ (crenulatin) CNT < (scopoletin) SCT < (scoparone) SCO < (isoscopoletin) IST < (4-methylesculetin) MST < (umbelliferone-2- carboxylic acid) UCA < (isofraxidin) IFD < (fraxetin) FXT < (aesculetine) ACT < (dapnetine) DPT. Therefore, UBA molecule in gas phase is less stable. Compared to the measured index of electrophilicity (DE). The MST molecule is stronger, more reactive, nucleophile electrophile at the gas phase and in solvents. In all solvent phases, CNT and UCA molecules have lower values, which mean they are strong nucleophiles. From the log P values of ACT and MST coumarins are in between 1.35-1.8, so ACT and MST coumarins use oral and intestinal absorptions.

SOLVENT EFFECTS ON THE ELECTRONIC STRUCTURE AND NON-LINEAR OPTICAL PROPERTIES OF PYRENE AND SOME OF ITS DERIVATIVES BASED ON DENSITY FUNCTIONAL THEORY

2021 ◽  
Vol 4 (4) ◽  
pp. 236-251
Author(s):  
A. S. Gidado ◽  
L. S. Taura ◽  
A. Musa
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Energy Gap ◽  
Chemical Reactivity ◽  
Basis Set ◽  
Lumo Energy ◽  
Functional Theory ◽  
Organic Optoelectronic ◽  
Homo Lumo

Pyrene (C16H10) is an organic semiconductor which has wide applications in the field of organic electronics suitable for the development of organic light emitting diodes (OLED) and organic photovoltaic cells (OPV). In this work, Density Functional Theory (DFT) using Becke’s three and Lee Yang Parr (B3LYP) functional with basis set 6-311++G(d, p) implemented in Gaussian 03 package was  used to compute total energy, bond parameters, HOMO-LUMO energy gap, electron affinity, ionization potential, chemical reactivity descriptors, dipole moment, isotropic polarizability (α), anisotropy of polarizability ( Δ∝) total first order hyper-polarizability () and second order hyperpolarizability (). The molecules used are pyrene, 1-chloropyrene and 4-chloropyrene  in gas phase and in five different solvents: benzene, chloroform, acetone, DMSO and water. The results obtained show that solvents and chlorination actually influenced the properties of the molecules. The isolated pyrene in acetone has the largest value of HOMO-LUMO energy gap of and is a bit closer to a previously reported experimental value of  and hence is the most stable. Thus, the pyrene molecule has more kinetic stability and can be described as low reactive molecule. The calculated dipole moments are in the order of 4-chloropyrene (1.7645 D) < 1-chloropyrene (1.9663 D) in gas phase. The anisotropy of polarizability ( for pyrene and its derivatives were found to increase with increasing polarity of the solvents.  In a nutshell, the molecules will be promising for organic optoelectronic devices based on their computed properties as reported by this work.

scholarly journals A Computational Study of Optoelectronic and Charge Transport Properties of Purine Nucleobases Dinucleotides Compounds

2021 ◽  
Author(s):  
Kimberly Madison ◽  
Wojciech Kolodziejczyk ◽  
Karina Kapusta ◽  
Glake Hill
Keyword(s):  
Density Functional Theory ◽  
Charge Transport ◽  
Transport Properties ◽  
Gas Phase ◽  
Density Functional ◽  
Energy Gap ◽  
Computational Study ◽  
Blue Shift ◽  
Functional Theory ◽  
Vertical Excitation

Abstract Optoelectronic and charge transport properties of eight novel compounds are presented in this work. Density functional theory B3LYP was utilized to optimize all structures while time-dependent density functional theory was utilized for vertical excitation characteristics. Gas and solvent phases (water, THF, and DCM) were evaluated to gain insight on solid-state and solution processed devices. While the solvent phases enhanced most of the charge transport properties, there was seen a blue-shift in their absorption wavelengths. However, C2, C4, C6, and C8 in THF absorption maxima were the highest and similar to those of the gas phase (605-652 nm). Extension of the polymer size decreased the HOMO-LUMO gap energy with C7 having the lowest energy gap in the gas phase. Although tuning the properties in optoelectronic devices is challenging, these findings will assist with the design of higher quality materials that could surpass the quality of inorganic devices.

Theoretical investigation of solvent effect on the keto-enol tautomerization of pentane-2,4-dione and a comparison between experimental data and theoretical calculations

2020 ◽  
Author(s):  
Sepideh Mehrani ◽  
Sayyed Faramarz Tayyari ◽  
Mohamad Momen-Heravi ◽  
Ali Morsali
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Equilibrium Constants ◽  
Solvent Polarity ◽  
Hybrid Functional ◽  
Functional Theory ◽  
Mechanical Methods ◽  
Intramolecular Hydrogen

The equilibrium constants of stable keto and enol forms of pentane-2,4-dione (known as acetylacetone) are estimated, using the second-order Møller−Plesset (MP2), density functional theory (B3LYP and M06-2X), composite methods (G4, G3, G3B3, CBS-QB3, and G3MP2B3), and double-hybrid density functional theory (B2PLYP), long-range corrected (LC) hybrid functional (ωB97X-D). These methods are integrated with the PCM, CPCM, and SMD models to elucidate the effect of solvent on thermodynamic parameters. The reported measured enol contents in the solutions and gas phase are utilized to benchmark the predictions of different quantum mechanical methods for the keto-enol equilibrium in acetylacetone, AA. In this study, we calculated the enol content in sixteen acetylacetone solutions as well as in the gas phase. Among the applied methods, the MP2 level underestimates while the B3LYP level overestimates the enol content of acetylacetone in the gas phase and solutions. The G3B3 and G3MP2B3 levels give reasonable agreement with the measured data. The best results obtained by calculations at the B2PLYP/6-31+G(2d,p) and CBS-QB3 levels, with mean absolute errors (MAE) relative to experiments of 2.30 and 5.45 and root mean square deviation (RMSD) errors in the 0.78 and 1.66 respectively. According to our calculations, one enol and two keto forms (Ket1 and Ket2) coexist in polar solutions. The effect of the solvent was more pronounced on the structure and stability of Ket2 tautomer than others. The strength of the intramolecular hydrogen bond in the enol form of AA is almost independent of the solvent polarity.

scholarly journals Synthesis and Theoretical Calculations of 2-(p-Tolyl)-2,3-Dihydro-1H-Perimidine using Density Functional Theory

2021 ◽  
Vol 18 (1) ◽  
pp. 75-85
Author(s):  
Vishnu A. Adole ◽  
Ganesh B. Yelmame
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Gap ◽  
Theoretical Calculations ◽  
Chemical Properties ◽  
Dft Method ◽  
Ring Closure ◽  
Functional Theory ◽  
Spectral Techniques ◽  
And Chemical Properties

In the present study, 2-(p-tolyl)-2,3-dihydro-1H-perimidine (TDHP) is synthesized from 1,8-naphthalenediamine and 4-methylbenzaldehyde by embedding a one-carbon unit between the nitrogen followed by ring closure using green chemistry approach. 1H NMR and 13C NMR spectral techniques were used to validate the structure of the TDHP. The synthesized perimidine TDHP is studied using density functional theory (DFT) to provide valuable insights into structural, chemical, and thermochemical study.The structural and chemical properties of TDHP were computed using the DFT method on the B3LYP/6-311G(d,p) basis package. Bond lengths were predicted from the optimised molecular structure, and the physical and chemical properties of the molecules were inferred as a consequence. The HOMO and LUMO are computed, and quantum chemical parameters are determined using electronic energies. The calculated HOMO-LUMO energy gap is 4.25 eV indicating charge transfer phenomenon within the molecule. The electron density and chemical behaviour of the TDHP was predicted using Mulliken atomic charges and the molecular electrostatic surface potential plot.Amongst all carbon atoms, the C8 carbon as more positive and C27 as more negative carbon atoms. The high global electrophilicity index suggests electrophilic character of the TDHP.The harmonic vibrational frequencies were used to measure total energy, total molar entropy, and molar heat capacity.

scholarly journals Physicochemical, antioxidant properties of carotenoids and its optoelectronic and interaction studies with chlorophyll pigments

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ruby Srivastava
Keyword(s):  
Density Functional Theory ◽  
Antioxidant Activity ◽  
Gas Phase ◽  
Density Functional ◽  
Energy Gap ◽  
Antioxidant Properties ◽  
Visible Region ◽  
State Theory ◽  
Chemical Hardness ◽  
Functional Theory

AbstractThe physicochemical and antioxidant properties of seven carotenoids: antheraxanthin, β-carotene, neoxanthin, peridinin, violaxanthin, xanthrophyll and zeaxanthin were studied by theoretical means. Then the Optoelectronic properties and interaction of chlorophyll-carotenoid complexes are analysed by TDDFT and IGMPLOT. Global reactivity descriptors for carotenoids and chlorophyll (Chla, Chlb) are calculated via conceptual density functional theory (CDFT). The higher HOMO–LUMO (HL) gap indicated structural stability of carotenoid, chlorophyll and chlorophyll-carotenoid complexes. The chemical hardness for carotenoids and Chlorophyll is found to be lower in the solvent medium than in the gas phase. Results showed that carotenoids can be used as good reactive nucleophile due to lower µ and ω. As proton affinities (PAs) are much lower than the bond dissociation enthalpies (BDEs), it is anticipated that direct antioxidant activity in these carotenoids is mainly due to the sequential proton loss electron transfer (SPLET) mechanism with dominant solvent effects. Also lower PAs of carotenoid suggest that antioxidant activity by the SPLET mechanism should be a result of a balance between proclivities to transfer protons. Reaction rate constant with Transition-State Theory (TST) were estimated for carotenoid-Chlorophyll complexes in gas phase. Time dependent Density Functional Theory (TDDFT) showed that all the chlorophyll (Chla, Chlb)–carotenoid complexes show absorption wavelength in the visible region. The lower S1–T1 adiabatic energy gap indicated ISC transition from S1 to T1 state.

Theoretical and Experimental Evaluation of the Effect of Fluorinated Substituent on the Topological Landscape and Thermodynamic Stability of Zeolitic Imidazolate Framework Polymorphs

2018 ◽  
Author(s):  
Mihails Arhangelskis ◽  
Athanassis Katsenis ◽  
Novendra Novendra ◽  
Zamirbek Akimbekov ◽  
Dayaker Gandrath ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Mechanochemical Synthesis ◽  
Thermodynamic Stability ◽  
Experimental Evaluation ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Zeolitic Imidazolate Framework ◽  
Functional Theory ◽  
Calorimetric Measurements ◽  
And Calorimetry

By combining mechanochemical synthesis and calorimetry with theoretical calculations, we demonstrate that dispersion-corrected periodic density functional theory (DFT) can accurately survey the topological landscape and predict relative energies of polymorphs for a previously inaccessible fluorine-substituted zeolitic imidazolate framework (ZIF). Experimental screening confirmed two out of three theoretically anticipated polymorphs, and the calorimetric measurements provided an excellent match to theoretically calculated energetic difference between them.<br>

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