Theoretical DFT, vibrational and NMR studies of benzimidazole and alkyl derivatives

Infante-Castillo, Ricardo; Rivera-Montalvo, Luis A.; Hernández‐Rivera, Samuel P.

doi:10.1016/j.molstruc.2007.07.012

Cited by 44 publications

(14 citation statements)

References 18 publications

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“…These bands have been observed at 1372 and 11276 cm À1 for HF and at 1356 and 1267 cm À1 for B3LYP in the theoretical spectra of the title compound. All these data agree with those reported in the literature [63,64].…”

Section: Infrared Spectrumsupporting

confidence: 93%

Quantum‐chemical, IR, NMR, and X‐ray diffraction studies on 2‐(4‐chlorophenyl)‐1‐methyl‐ 1H‐benzo[d]imidazole

Özdemir

Eren

Di̇nçer

et al. 2011

Int J of Quantum Chemistry

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The title molecule, 2-(4-chlorophenyl)-1-methyl-1H-benzo[d]imidazole (C 14 H 11 ClN 2 ), was prepared and characterized by 1 H NMR, 13 C NMR, IR, and singlecrystal X-ray diffraction. The molecular geometry, vibrational frequencies, and gauge including atomic orbital (GIAO) 1 H and 13 C NMR chemical shift values of the title compound in the ground state have been calculated by using the Hartree-Fock (HF) and density functional theory (DFT/B3LYP) method with 6-31G(d) basis sets, and compared with the experimental data. The calculated results show that the optimized geometries can well reproduce the crystal structural parameters, and the theoretical vibrational frequencies and GIAO 1 H and 13 C NMR chemical shifts show good agreement with experimental values. The energetic behavior of the title compound in solvent media has been examined using B3LYP method with the 6-31G(d) basis set by applying the Onsager and the polarizable continuum model (PCM). Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis, and nonlinear optical (NLO) properties of the title compound were investigated by theoretical calculations.

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Section: Infrared Spectrumsupporting

confidence: 93%

Quantum‐chemical, IR, NMR, and X‐ray diffraction studies on 2‐(4‐chlorophenyl)‐1‐methyl‐ 1H‐benzo[d]imidazole

Özdemir

Eren

Di̇nçer

et al. 2011

Int J of Quantum Chemistry

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“…2(A). All spectra were collected in the range from 300 to 2000 cm −1 to cover most Raman bands of RDX along with the conventional Raman spectrum of pure RDX for comparison 36. Since only the vibrational modes of analyte moieties adsorbed on the Au surface are enhanced, there are typically fewer peaks in the SERS spectrum than in the conventional Raman spectrum (without using gold as an SERS substrate).…”

Section: Resultsmentioning

confidence: 99%

Determination of Band Structure Parameters and the Quasi‐Particle Gap of CdSe Quantum Dots by Cyclic Voltammetry

2008

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Band structure parameters such as the conduction band edge, the valence band edge and the quasi-particle gap of diffusing CdSe quantum dots (Q-dots) of various sizes were determined using cyclic voltammetry. These parameters are strongly dependent on the size of the Q-dots. The results obtained from voltammetric measurements are compared to spectroscopic and theoretical data. The fit obtained to the reported calculations based on the semi-empirical pseudopotential method (SEPM)-especially in the strong size-confinement region, is the best reported so far, according to our knowledge. For the smallest CdSe Q-dots, the difference between the quasi-particle gap and the optical band gap gives the electron-hole Coulombic interaction energy (J(e1,h1)). Interband states seen in the photoluminescence spectra were verified with cyclic voltammetry measurements.

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“…Only examples where the 13 C experimental spectra were of high quality were chosen for analysis. At the selection stage, we observed that some authors [48] used for the evaluation of QM methods experimental spectra which differed significantly from the available reference spectra. In such cases, we used the reference experimental 13 C NMR spectra which are present in the ACD/Labs database or in the Aldrich spectral atlas.…”

Section: Data Selection and Processingmentioning

confidence: 99%

Empirical and DFT GIAO quantum‐mechanical methods of ¹³C chemical shifts prediction: competitors or collaborators?

Elyashberg¹,

Blinov²,

Smurnyy³

et al. 2010

Magnetic Reson in Chemistry

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The accuracy of (13)C chemical shift prediction by both DFT GIAO quantum-mechanical (QM) and empirical methods was compared using 205 structures for which experimental and QM-calculated chemical shifts were published in the literature. For these structures, (13)C chemical shifts were calculated using HOSE code and neural network (NN) algorithms developed within our laboratory. In total, 2531 chemical shifts were analyzed and statistically processed. It has been shown that, in general, QM methods are capable of providing similar but inferior accuracy to the empirical approaches, but quite frequently they give larger mean average error values. For the structural set examined in this work, the following mean absolute errors (MAEs) were found: MAE(HOSE) = 1.58 ppm, MAE(NN) = 1.91 ppm and MAE(QM) = 3.29 ppm. A strategy of combined application of both the empirical and DFT GIAO approaches is suggested. The strategy could provide a synergistic effect if the advantages intrinsic to each method are exploited.

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Theoretical DFT, vibrational and NMR studies of benzimidazole and alkyl derivatives

Cited by 44 publications

References 18 publications

Quantum‐chemical, IR, NMR, and X‐ray diffraction studies on 2‐(4‐chlorophenyl)‐1‐methyl‐ 1H‐benzo[d]imidazole

Quantum‐chemical, IR, NMR, and X‐ray diffraction studies on 2‐(4‐chlorophenyl)‐1‐methyl‐ 1H‐benzo[d]imidazole

Determination of Band Structure Parameters and the Quasi‐Particle Gap of CdSe Quantum Dots by Cyclic Voltammetry

Empirical and DFT GIAO quantum‐mechanical methods of ¹³C chemical shifts prediction: competitors or collaborators?

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Theoretical DFT, vibrational and NMR studies of benzimidazole and alkyl derivatives

Cited by 44 publications

References 18 publications

Quantum‐chemical, IR, NMR, and X‐ray diffraction studies on 2‐(4‐chlorophenyl)‐1‐methyl‐ 1H‐benzo[d]imidazole

Quantum‐chemical, IR, NMR, and X‐ray diffraction studies on 2‐(4‐chlorophenyl)‐1‐methyl‐ 1H‐benzo[d]imidazole

Determination of Band Structure Parameters and the Quasi‐Particle Gap of CdSe Quantum Dots by Cyclic Voltammetry

Empirical and DFT GIAO quantum‐mechanical methods of 13C chemical shifts prediction: competitors or collaborators?

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Empirical and DFT GIAO quantum‐mechanical methods of ¹³C chemical shifts prediction: competitors or collaborators?