The Vibrational Spectroscopic ( FTIR & FTR ) study and HOMO & LUMO analysis of 6-Methyl Quinoline using DFT Studies (original) (raw)
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Experimental and theoretical studies on IR, Raman and UV-Vis spectra of quinoline-7-carboxaldehyde
Spectroscopic properties of quinoline-7-carboxaldehyde (Q7C) have been studied in detail both experi-mentally and theoretically. The FT-IR (4000–50cm-1), FT-Raman (4000–50cm-1), dispersive-Raman (3500–50cm-1), and UV–Vis (200–400nm) spectra of Q7C were recorded at room temperature (25ºC). Geometry parameters, potential energy surface about CACH(O) bond, harmonic vibrational fre-quencies, IR and Raman intensities, UV–Vis spectrum, and thermodynamic characteristics (at 298.15K) of Q7C were computed at Hartree–Fock (HF) and density functional B3LYP levels employing the 6-311++G(d,p) basis set. Frontier molecular orbitals, molecular electrostatic potential, and Mulliken charge analyses of Q7C have also been performed. Q7C has two stable conformers that are energetically very close to each other with slight preference to the conformer that has oxygen atom of the aldehyde away from the nitrogen atom of the quinoline.
Vibrational spectroscopic study of some quinoline derivatives
Vibrational Spectroscopy, 2016
This work deals with the successful synthesis, spectroscopic properties (Raman and infrared) and theoretical calculations of some quinoline derivatives, namely 4-azido-7chloroquinoline and the commercially available 4,7-dichloroquinoline, quinolin-8-ol. The analysis of the Raman and infrared spectra of the quinoline derivatives, supported by DFT calculations, for the first time has afforded the opportunity to characterize unambiguously the main vibrational bands for these important molecules, which are mainly used as anti-malaria compounds. Despite the very similar structures of these quinolines the Raman and infrared spectra exhibit significant wavenumber shifts for several key bands. A characteristic band at ca. 1580 cm-1 can be assigned involving a δ(OH) mode for quinolin-8-ol (QNO) as well as the band at ca. 1090 cm-1 attributed to δ(CCl) for 4,7-dichloroquinoline (DCQN). The compound 4-azido-7-chloroquinoline (ACQN) shows a very characteristic marker band at ca. 1300 cm-1 , which has been assigned to the ν(NN) mode of the azide group.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 2014
Quinoline derivatives have good nonlinear optical properties and have been extensively studied due to their great potential application in the field of organic light emitting diodes. Quantum chemical calculations of the equilibrium geometry, harmonic vibrational frequencies, infrared intensities and Raman activities of 4-hydroxy-2-oxo-1,2-dihydroquinoline-7-carboxylic acid in the ground state were reported. Potential energy distribution of normal modes of vibrations was done using GAR2PED program. The synthesis, (1)H NMR and PES scan results are also discussed. Nonlinear optical behavior of the examined molecule was investigated by the determination of first hyperpolarizability. The calculated HOMO and LUMO energies show the chemical activity of the molecule. The stability of the molecule arising from hyperconjugative interaction and charge delocalization has been analyzed using NBO analysis. The calculated geometrical parameters are in agreement with that of similar derivatives.
Quinoline-Based Materials: Spectroscopic Investigations as well as DFT and TD-DFT Calculations
Journal of Chemistry, 2022
Quinoline derivatives such as 15,15-difluoro-[1,3,2] diaazaborininodiquinoline (DDP) and 15,15-difluoro-[1,3,2] diaazaborininodiquinoline acetonitrile (DDPA) have a range of biological and medical activities. So, it is vital to shed light on these compounds in terms of their optical properties supported by quantum calculations. The absorption and emission spectra of studied compounds were measured within the laboratory, whereas the quantum calculations were performed utilizing the density functional theory (DFT) calculations. Additionally, the time-dependent density functional theory (TD-DFT) was applied for the comparison of some sensible results with the theoretical ones. The molecular structures of these compounds were presented via applying chemical analysis techniques. The electronic absorption spectra of DDP and DDPA molecular structures were monitored through an experiment in hosts such as carbon tetrachloride (CCl4), chloroform (CHCl3), methylene dichloride (CH2Cl2), acetone...
Journal of Molecular Structure, 2016
Comparative experimental and theoretical studies have been performed on the structure and spectral (FT-IR, FT-Raman, UV-Vis and NMR) features of quinoline-5-carboxaldehyde. Quantum chemical calculations have been carried out at Hartree-Fock and density functional B3LYP levels with the triple-zeta 6-311++G** basis set. Two stable conformers of quinoline-5carboxaldehyde arising from the orientation of the carboxaldehyde moiety have been located at the room temperature. The energetic separation of these conformers is as small as 2.5 kcal/mol with a low transition barrier (around 9 kcal/mol). Therefore, these conformers are expected to coexist at the room temperature. Several molecular characteristics of quinoline-5carboxaldehyde obtained through B3LYP and time-dependent B3LYP calculations, such as conformational stability, key geometry parameters, vibrational frequencies, IR and Raman intensities, UV-Vis vertical excitation energies and the corresponding oscillator strengths have been analyzed. The 1 H and 13 C NMR chemical shifts of quinoline-5-carboxaldehyde were also investigated.
Journal of Advanced Scientific Research
In this article theoretical DFT work on quinoxaline derivative is reported. Quantum mechanical calculations of different energies components of 11-Chloro-12(Methylsulfanyl) Quinoxaline [11Cl12MsQ] in ground state were carried out by DFT method, in isolated state and in different solvents to study the effects of solvents on various energy components. The influence of these solvents on optimized geometry, Mulliken charge distribution in ground and excited state were studied. With the help of computed highest occupied molecular orbital (HOMO) - lowest unoccupied molecular orbital (LUMO) gap of 11Cl12MsQ in different medium we can compute solvation energy, ionization potential, electron affinity, chemical hardness, electron chemical potential, electronegativity and global electrophilicity. UV-Vis spectrum and emission energy were analysed using TDDFT method. The density distribution analysis by total electron density (TED), potential distribution over molecule by electrostatic potential...
Indian Journal of Pure & Applied Physics, 2020
The solvatochromic studies in a Quinoline derivative molecule namely Quinolin-8-ol (QO) have been carried out at ambient temperature using absorption and fluorescence spectroscopy. The QO molecule shows the bathochromic shift with increase in solvent polarity demonstrating π → π * transition. The solvatochromic data coupled with quantum mechanical calculations has been used to estimate change in dipole moment of the molecule after excitation. It has been found that excited state dipole moment is greater than the corresponding ground state dipole moment. Further, it is observed that excited and ground state dipole moments are parallel. The chemical reactivity and kinetic stability of QO molecule are investigated using Frontier molecular orbital (FMO) analysis. Natural bond orbital (NBO) analysis shows proton transfer within the selected donor-acceptor depicting large energy of stabilization for QO molecule. The calculated Fukui functions infer the local softness and local eletrophili...
Chemical Data Collections, 2019
FT-IR and FT-Raman spectra of 7,7,8,8-tetracyanoquinodimethane(TCNQ) was recorded and analyzed. The equilibrium geometry, various bonding features and harmonic vibrational wavenumbers of TCNQ and its related compounds have been performed using density functional theory(DFT) method with 6-311G(d,p) basis set. The detailed interpretation of the vibrational spectra has been carried out with the aid of Molvib program. The TD-DFT calculation has been compared with UV-Vis spectrum with different solvents. HOMO-LUMO energy gap, local softness and electrophlicity indices for selected atomic sites of the TCNQ and its related compounds were determined. The intermolecular interaction in the TCNQ were confirmed by using Hirshfeld surfaces. The NLO activity of molecule was confirmed by SHG analysis. The surface resistance and third-order nonlinear optical property of the crystal were studied by laser induced surface damage threshold and Z-scan techniques respectively using Nd:YAG laser with wavelength 532 nm.
Quantum Chemical and Spectroscopic Investigations of 5-quinolinamine
2010
The Fourier transform infrared (FTIR) and FT-Raman spectra of 5-aminoquinoline (5AQ) have been recorded in the range 4000-400 and 3500-100 cm −1 , respectively. The complete vibrational assignment and analysis of the fundamental modes of the compounds were carried out using the observed FTIR and FT-Raman data. 1 H and 13 C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by using the gauge independent atomic orbital (GIAO) method. UV-vis spectrum of the compound was recorded and the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The geometric parameters, chemical shifts and absorption wavelengths were compared with the experimental data of the molecule. The vibrational frequencies which were determined experimentally are compared with those obtained theoretically from ab initio HF and DFT-B3LYP gradient calculations employing the 6-31G** and 6-311++G** basis sets for optimized geometries of the compound. The interactions of NH-and the influence of amino group on the skeletal modes are investigated.
FT-IR and FT-Raman spectra of 4-chlorophenyl quinoline-2-carboxylate were recorded and analyzed. The vibrational wavenumbers were computed using DFT quantum chemical calculations. The data obtained from wavenumber calculations are used to assign vibrational bands obtained experimentally. Potential energy distribution was done using GAR2PED program. The geometrical parameters obtained theoretically are in agreement with the XRD data. NBO analysis, HOMO-LUMO, first hyperpolarizability and molecular electrostatic potential results are also reported. The calculated hyperpolarizability of the title compound is 77.53 times that of the standard NLO material urea and the title compound and its derivatives are attractive object for future studies of nonlinear optical properties. Molecular docking results suggest that the compound might exhibit inhibitory activity against GPb. keywords:DFT; FT-IR; FT-Raman; quinoline; Molecular docking.