Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
2.
J Mol Model ; 28(11): 373, 2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36322186

RESUMO

Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations are used to investigate the effect of methoxy and anisyl molecules attached to perylene, as well as the different positions of the sensitizers' π-spacers. The optical, spectroscopic, and electrochemical properties of designed sensitizers are investigated in dye-sensitized solar cell (DSSC) applications. Perylene serves as an electron donor and cyanoacrylic acid serves as an acceptor in the sensitizers under investigation. In the six configurations designed, cyanovinyl and thiophene are used as π-spacers. Methoxy and anisyl groups are two more donors that were combined with perylene to study the sensitizers' optoelectronic properties. UV-vis absorption spectra, light-harvesting efficiency (LHE), highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gap, electron injection, electron regeneration, and nonlinear optical properties were used to compare optical and electronic properties. The incorporation of additional donors and different positions of spacers reduced the energy gap; red shifted the absorption spectra; and are prone to exhibit better power conversion efficiency (PCE) of the DSSC.

3.
Heliyon ; 8(5): e09539, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35663763

RESUMO

Quercitrin is an anti-lung cancer agent. It is a naturally occurring flavonoid and its derivatives are mainly present in nuts and beverages. It is mainly available as a glycoside, and the quercitrin glycosides are found to prevent the metastasis of cancer. Quercitrin is optimized with 6-311++G(d,p) basis set using the B3LYP method to attain its minimum energy structure. The vibrational studies of the Quercitrin compound were elucidated with reference to Potential Energy Distribution (PED). The geometrical parameters were obtained and correlated with experimental values. To examine the nature of the charge transfer mechanism of Quercitrin, the HOMO-LUMO energy gap is computed. The anti-cancer activity of Quercitrin has been explored using molecular docking study that are used to estimate how the ligand interacts with protein, specifically to identify the best-fit orientation of the ligand, its binding mode, and intermolecular interactions of amino acid residues in the binding region of B-RAF kinase protein. The binding affinity of the compound Quercitrin (-7.14 kcal/mol) was found using AutoDock and validated with a Glide XP score in Schrodinger tool (-8.01 kcal/mol). MD simulations of protein-ligand complexes were monitored for 100 ns, from which the RMSD, RMSF, Rg, H-bonds, and interaction energy calculations were executed. From these investigations, it is identified that the compound quercitrin has maintained good structural stability, compactness, higher Hydrogen bonds, and interaction energies than the Imidazopyridinyl benzamide inhibitor.

4.
J Mol Model ; 28(4): 102, 2022 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-35338408

RESUMO

A series of perylene-based novel metal-free organic dye sensitizers are designed and optimized for dye-sensitized solar cell (DSSC) applications. The electronic and optical properties are analyzed through density functional theory (DFT) and time-dependent density functional theory (TD-DFT) approach. For perylene-based donors, the effects of additional donor units and different π-spacer positions were investigated. Cyanovinyl and thiophene are used as π-spacers, dimethylamine (DM) and N-N-dimethylaniline (DMA) are used as additional donors, and cyanoacrylic acid is used as mono acceptor unit for the designed sensitizers. Natural bonding orbitals (NBOs), frontier molecular orbitals (FMO), UV-Vis, and nonlinear orbital analysis were predicted to find the net electron transfer, energy gap, absorption spectra, and electronic charge distribution for perylene-based dye sensitizers, respectively. The electron injection and electron regeneration properties were also analyzed for perylene-based sensitizers.

5.
Mater Sci Eng C Mater Biol Appl ; 125: 112095, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33965105

RESUMO

The intentional design of rare earth doped luminescent architecture exhibits unique optical properties and it can be considered as a promising and potential probe for optical imaging applications. Calcium fluoride (CaF2) nanoparticles doped with optimum concentration of Nd3+ and Yb3+ as sensitizer and activator, respectively, were synthesized by wet precipitation method and characterized by x-ray diffraction (XRD) and photoluminescence. In spite of the fact that the energy transfer takes place from Nd3+ to Yb3+, the luminescence intensity was found to be weak due to the lattice defects generated from the doping of trivalent cations (Nd3+ and Yb3+) for divalent host cations (Ca2+). These defect centres were tailored via charge compensation approach by co-doping Na+ ion and by optimizing its concentration and heat treatment duration. CaF2 doped with 5 mol% Nd3+, 3 mol% Yb3+ and 4 mol% Na+ after heat treatment for 2 h exhibited significantly enhanced emission intensity and life time. The ex vivo fluorescence imaging experiment was done at various thickness of chicken breast tissue. The maximum theoretical depth penetration of the NIR light was calculated and the value is 14 mm. The fabricated phosphor can serve as contrast agent for deep tissue near infrared (NIR) light imaging.


Assuntos
Metais Terras Raras , Nanopartículas , Corantes Fluorescentes , Luminescência , Difração de Raios X
6.
Heliyon ; 7(4): e06646, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33898809

RESUMO

The IUPAC name of curcumin is (1E, 6E)-1,7-Bis(4-hydroxy-3methoxyphenyl) hepta-1,6-e-3,5-dione (7B3M5D) and is characterized by spectroscopic profiling with FT-IR and FT-Raman spectra obtained both experimentally and theoretically. PED analysis was done for the confirmation of minimum energy obtained in the title compound. Optimized geometrical parameters are compared with experimental values obtained for 7B3M5D by utilizing B3LYP functional employing 6-311++G (d,p) level of theory. The HOMO-LUMO, MEP, and Fukui function analysis has been used to elucidate the information regarding charge transfer within the molecule. The stabilization energy and charge delocalization of the 7B3M5D were performed by NBO analysis. This article assesses that the title compound act as a potential inhibitor of the PI3K/AKT inhibitor through in silico studies, like molecular docking, molecular dynamics (MD), ADMET prediction and also this molecule obeys Lipinski's rule of five. 7B3M5D was docked effectively in the active site of PI3K/AKT inhibitor.

7.
Heliyon ; 6(8): e04641, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32904270

RESUMO

The Cyclophosphamide (CYC) is used as an anti cancer agent. It is chemically known as (RS)-N,N-bis(2-chloroethyl)-1,3,2-oxazaphosphinan-2-amine 2-oxide. The vibrational assignments survey of the CYC was implemented by employing FT-IR and FT-Raman spectroscopic investigation and the results are compared with theoretical features. The optimized geometrical parameters, IR intensity and Raman Activity of the vibrational bands of CYC were determined from the B3LYP functional with 6-311++G (d, p) level of theory. In the current work, quantum chemical calculations were adopted to contemplate the vibrational assignments of CYC and the outcomes are compared with experimental findings. Molecular Electrostatic Potential (MEP) and HOMO-LUMO energies are very effective in the examination of charge transfer and distribution of the molecular structure. The molecular orbital contributions were evaluated by using the Total Density of States (TDOS). The analysis of Natural Bond Orbital (NBO), Mulliken population and Fukui function studies were done. Intermolecular interaction of the title compound was examined through Hirshfeld surface analysis. The evaluation of drug-likeness was accomplished in accordance with Lipinski's Rule of Five and molecular descriptors were utilized to predict the ADMET profiles of the CYC molecule. The recent research studies reports that the structural and bio-activity of the CYC was affirmed by the docking analysis of CYC with protein PI3K/AKT inhibitor, it acts as anti-lung cancer agent.

8.
Heliyon ; 5(7): e01988, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31372525

RESUMO

Single crystals of pure and NaCl doped sulphamic acid (SA) were grown by slow evaporation method at room temperature. The lattice parameters and structure were determined by using single crystal and powder X-ray diffraction analyses. The presence of dopant in the SA lattice was affirmed by EDAX analysis. UV-Vis spectra show maximum transmittance in the visible region. The band gap energies were found to be 6.06 eV and 5.70 eV for pure and NaCl doped SA crystals respectively. From the PL specta the emission were observed at 335 and 424 nm for pure and 340 and 428 nm for doped SA crystal. The thermal stability of the grown crystals were analyzed by thermogravimetric and differential thermal analysis (TGA/DTA) and revealed that the grown crystals were thermally stable up to 331 °C and 334 °C for pure and NaCl doped SA. Vickers microhardness study reveals that the hardness of the crystals is increase with increasing load. The photoconductivity study shows that the grown crystals are negative photoconductive nature. The Laser Damage Threshold (LDT) indicates the grown crystals have good resistance to laser radiation than a standard Potassium dihydrogen phosphate (KDP) crystal. The Z-scan technique was employed to determine the nonlinear refractive index, nonlinear optical absorption and third order nonlinear optical (TONLO) susceptibility of the grown crystals using He-Ne laser.

9.
Artigo em Inglês | MEDLINE | ID: mdl-24177883

RESUMO

The Fourier Transform infrared and Fourier Transform Raman spectra of 7-chloro-5 (2-chlorophenyl)-3-hydroxy-2,3-dihydro-1H-1,4-benzodiazepin-2-one (7C3D4B) were recorded in the regions 4000-400 and 4000-100 cm(-1), respectively. The appropriate theoretical spectrograms for the IR and Raman spectra of the title molecule were also constructed. The calculated results show that the predicted geometry can well reproduce the structural parameters. Predicted vibrational frequencies have been assigned and compared with experimental IR spectra and they supported each other. Stability of the molecule arising from hyperconjugative interactions, charge delocalization and intramolecular hydrogen bond-like weak interaction has been analyzed using natural bond orbital (NBO) analysis by using B3LYP/6-31G(d,p) method. The results show that electron density (ED) in the σ* and π* antibonding orbitals and second-order delocalization energies E(2) confirm the occurrence of intramolecular charge transfer (ICT) within the molecule. The first order hyperpolarizability (ßtotal) of this molecular system and related properties (ß, µ, and Δα) are calculated using HF/6-31G(d,p) and B3LYP/6-31G(d,p) methods based on the finite-field approach.


Assuntos
Benzodiazepinas/química , Hipnóticos e Sedativos/química , Ligação de Hidrogênio , Modelos Moleculares , Teoria Quântica , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman
10.
Artigo em Inglês | MEDLINE | ID: mdl-23892343

RESUMO

FT-IR spectroscopy has been applied to investigate the potential nonlinear optical (NLO) material 3-hydroxybenzaldehyde (3HBA). The equilibrium geometry, Fukui function, harmonic vibrational frequencies, infrared intensities, and thermodynamic properties of 3HBA and its cation were calculated by HF/6-31G(d,p) and density functional theory B3LYP/6-31G(d,p), B3LYP/6-311++G(d,p) methods. The first order hyperpolarizability (ßtotal) of this molecular system and related properties (ß, µ, and Δα) are calculated based on the finite-field approach. Stability of the molecule arising from hyperconjugative interactions, charge delocalization and intramolecular hydrogen bond-like weak interaction has been analyzed using natural bond orbital (NBO) analysis by using B3LYP/6-311++G(d,p) method. The results show that electron density (ED) in the σ(*) and π(*)anti-bonding orbitals and second-order delocalization energies E((2)) confirm the occurrence of intramolecular charge transfer (ICT) within the molecule. The thermal stability of 3HBA and its cation is studied by the thermogravimetric analysis (TGA). The harmonic-vibrational frequencies were calculated and the scaled values have been compared with experimental FT-IR spectrum. The observed and the calculated frequencies are found to be in good agreement. The experimental spectrum also coincides satisfactorily with those of theoretically constructed spectrograms.


Assuntos
Benzaldeídos/química , Elétrons , Modelos Moleculares , Teoria Quântica , Vibração , Cátions/química , Conformação Molecular , Dinâmica não Linear , Fenômenos Ópticos , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Termodinâmica , Termogravimetria
11.
Artigo em Inglês | MEDLINE | ID: mdl-23732619

RESUMO

The FT-IR and FT-Raman spectrum of 7-chloro-2-methylamino-5-phenyl-3H-1, 4-benzodiazepine-4-oxide (7CMP4BO) has been recorded in the region 4000-400 and 4000-100 cm(-1) respectively. The optimized geometry, Thermodynamic properties, NBO, Molecular Electrostatic Potentials, PES, frequency and intensity of the vibrational bands of 7CMP4BO were obtained by the ab initio HF and density functional theory (DFT), B3LYP/6-31G (d,p) basis set. The molecule orbital contributions were studied by using the total (TDOS), partial (PDOS), and overlap population (OPDOS) density of states. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FT-IR and FT-Raman spectra. A detailed interpretation of the vibrational spectra of this compound has been made on the basis of the calculated potential energy distribution (PED). The linear polarizability (α) and the first order hyperpolarizability (ß) values of the investigated molecule have been computed using DFT quantum mechanical calculations. The observed and the calculated frequencies are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically calculated values.


Assuntos
Benzodiazepinas/química , Modelos Moleculares , Teoria Quântica , Análise Espectral Raman , Vibração , Conformação Molecular , Dinâmica não Linear , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Termodinâmica
12.
Artigo em Inglês | MEDLINE | ID: mdl-23376268

RESUMO

The Fourier transform infrared (FTIR) and FT-Raman spectra of 8-chloro-1-methyl-6-phenyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine (8C1M6PB) have been recorded in the range of 4000-400 and 4000-100 cm(-1), respectively. A detailed interpretation of the vibrational spectra of this compound has been made on the basis of the calculated potential energy distribution (PED). The equilibrium geometries, harmonic frequencies, infrared intensities and Raman scattering activities were calculated by Hartree-Fock (HF) and density functional B3LYP method with the 6-31G (d,p) basis set. The vibrational frequencies were calculated in all these methods and were compared with the experimental frequencies which yield good agreement between observed and calculated frequencies. The first order hyperpolarizability (ßtotal) of this molecular system and related properties (ß, µ, and Δα) are calculated using HF/6-31G (d,p) and B3LYP/6-31G(d,p) methods based on the finite-field approach. The calculated Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) energies show that charge transfer occurs in the molecule. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. Conformation analysis was carried for 8C1M6PB by Potential energy surface scan to find all possible conformers with B3LYP method using 6-31G (d,p) basis set. The entropy of the title compound is also performed at HF/6-31G (d,p) and B3LYP/6-31G(d,p) levels of theory. In addition, the thermodynamic properties of the compound were calculated at different temperatures and corresponding relations between the properties and temperature were also studied.


Assuntos
Benzodiazepinas/química , Triazóis/química , Modelos Moleculares , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman
13.
Echocardiography ; 28(2): 154-60, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21073514

RESUMO

BACKGROUND: Left atrium (LA) remodeling has a crucial adverse impact on outcome and prognosis in mitral stenosis. Few studies have reported the effect of balloon mitral valvuloplasty (BMV) on LA volume. The aim of this study was to assess the evolution of LA volume immediately and 1 month after successful BMV in patients in sinus rhythm. METHODS: Thirty-three consecutive patients (70% women; age 31 ± 8 years; range 19-45) with moderate to severe mitral stenosis (mitral valve area ≤1.5 cm(2) ) who underwent successful BMV were included prospectively. Using two-dimensional echocardiography, and according to the prolate ellipse method, LA volume and LA volume indexed to body surface area were determined before BMV, and 24 hours and 1 month after BMV. Tricuspid and pulmonary regurgitation jets were recorded systematically using continuous-wave Doppler. Pulmonary artery-right ventricular (PA-RV) gradients, reflecting pulmonary pressures, and pulmonary vascular resistance were measured. RESULTS: Mitral valve area increased from 0.88 ± 0.16 to 1.55 ± 0.26 cm(2) (P < 0.0001). Mean mitral valve gradient (MVG) decreased from 16 ± 6 to 6 ± 2 mmHg (P < 0.0001) immediately after BMV. Indexed LA volume fell from 56 ± 14 to 48 ± 12 mL/m(2) (P = 0.0002) immediately after BMV and to 45 ± 13 mL/m(2) at 1 month (P < 0.0001). Only patients with a median LA volume ≥55 mL/m(2) before BMV had a significant reduction in LA volume (P = 0.0001). Decrease in LA volume was correlated with decreases in PA-RV peak diastolic gradient (r = 0.45, P = 0.008) and MVG (r = 0.35, P = 0.04). CONCLUSION: In patients with mitral stenosis in sinus rhythm, successful BMV results in an immediate decrease in LA volume. This reduction, maximal immediately after BMV, correlates with decreases in MVG and PA-RV peak diastolic gradient, and is significant only when LA volume before BMV is severely enlarged.


Assuntos
Cateterismo , Átrios do Coração/fisiopatologia , Estenose da Valva Mitral/fisiopatologia , Estenose da Valva Mitral/cirurgia , Adulto , Pressão Sanguínea , Circulação Coronária , Ecocardiografia , Feminino , Átrios do Coração/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Estenose da Valva Mitral/diagnóstico por imagem , Tamanho do Órgão , Resultado do Tratamento , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA