Aromaticity indices, electronic structural properties, and fuzzy atomic space investigations of naphthalene and its aza-derivatives (original) (raw)
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Russian Journal of Physical Chemistry A, 2014
In this paper, the stabilities and hydrogen bond interactions of 4 chloro 1 naphthol, 1 hydrox ynaphthalene and 1,4 dihydroxynaphthalene dimers have been theoretically investigated by means of study on binding energies with nonlocal hybrid three parameter Lee-Yang-Parr, B3LYP, and M06 class func tional calculations. Calculations on dimers aim to provide as a test of the efficacy of M06 calculations for intermolecular interaction calculations and more strongly bound systems. For hydroxyl and halo substi tuted derivatives of naphthalene, total electronic energies, their correction for the zero point vibrational ener gies with some calculated thermodynamic properties and their relative differences are together in order to dis cuss the rotamer structures. Static (hyper) polarizabilities and the electric dipole moments, frontier molecu lar orbital energy gaps and the relationships between them have been interpreted. Generally, they are seen that the calculated geometric parameters and spectral results were in a good agreement with the corresponding experimental data.
The effect of Au metal electrodes on the Naphthalene molecule under external electric field and the corresponding electrostatic properties have been studied by analyzing the geometrical parameters as well as MPA and NPA atomic charges. All the quantum chemical calculations have been carried out with density functional theory (DFT) coupled with Bader's AIM theory under various applied EFs using Gaussian09 program package. As the field increases, the observed structural variations are small; however, in most cases it is found to be systematic and almost uniform. When the field increases from 0.00 to 0.15 VÅ -1 the hybridization of molecular levels broadens the DOS and decreases the HLG from 2.45 to 1.98 eV. Overall, the terminal groups of the Naphthalene are found to be very sensitive to applied field in comparison with those molecular regions.
Chemical Physics, 1993
In order to preselect possible candidates for the origin of diffuse interstellar bands observed, semiempirical quantum mechanical method INDO/S was applied to the optical spectra of neutral, cationic, and anionic states of naphthalene and its hydrogen abstraction and addition derivatives. Comparison with experiment shows that the spectra of naphthalene and its ions were reliably predicted. The configuration interaction calculations with single-electron excitations provided reasonable excited state wavefunctions compared to ab initio calculations that included higher excitations. The degree of similarity of the predicted spectra of the hydrogen abstraction and derivatives to those of naphthalene and ions depends largely on the similarity of the a electron contigurations. For the hydrogen addition derivatives, very little resemblance of the predicted spectra to naphthalene was found because of the disruption of the aromatic conjugation system. The relevance ofthese calculations to astrophysical issues is discussed within the context of these polycyclic aromatic hydrocarbon models. Comparing the calculated electronic energies to the diffuse interstellar bands (DIBs), a list of possible candidates of naphthalene derivatives is established which provides selected candidates for a definitive test through laboratory studies.
Density Functional Study of 2-[(R-Phenyl)amine]-1,4-naphthalenediones
Journal of Chemical Theory and Computation, 2007
The molecular and electronic structures of a series of 2-[(R-phenyl)amine]-1,4naphthalenediones (R) m-Me, p-Me, mEt , p-CF 3 , p-Hex, pEt , m-F, m-Cl, p-OMe, p-COMe, p-Bu, m-COOH, p-Cl, p-COOH, p-Br, m-NO 2 , m-CN, and p-NO 2) and their anions are investigated in the framework of density functional theory. The calculations are of all-electron type using a double zeta valence polarization basis set optimized for density functional theory methods. The theoretical study shows that all compounds are nonplanar. The nonplanarity can be rationalized in terms of occupied π orbitals. A linear correlation between the measured half-wave potentials and the calculated gas-phase electron affinities is found. It holds for local as well as generalized gradient corrected functionals. Structural parameters, harmonic vibrational frequencies, and adiabatic and vertical electron affinities as well as orbital and spin density plots of the studied compounds are presented.
Journal of Molecular Structure: …, 2001
The ground state molecular structure of different single-atom peri-bridged naphthalene compounds containing a fourmembered ring was studied by ab initio quantum chemistry and by density functional theory (DFT) using the Becke, Lee, Yang and Parr density functional method (B3LYP). Also, in some of these compounds, pyramidal atom inversion energy and its transition state structure along with the energetic stability of the favored intermediate in the electrophilic substitution, have been determined using these computational methods. q
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2011
A combined experimental and theoretical study on molecular and vibrational structure of 2,3-dimethyl naphthalene (2,3-DMN) has been undertaken in the present work. The FTIR and FT Raman spectra of 2,3-DMN were recorded in the region 4000-100 cm −1 . The optimized geometries were calculated by HF and DFT (B3LYP) methods with 6-31++G (d, p), 6-311G (d, p) and 6-311++G (d, p) basis sets. The harmonic vibrational frequencies, infrared intensities and Raman activities of the 2,3-DMN were evaluated with these methods. After scaling the computational wave numbers are in very good agreement with the experimental values. A detailed interpretation of the infrared and Raman spectra of 2,3-DMN is presented. The effects of substitution of methyl group on the molecule have also been discussed.
Bioorganic & Medicinal Chemistry Letters, 2002
Unambiguous assignments of monocarboxymethylnapthalenes isolated as oxidation products of dimethylnaphthalenes by Pseudomonas putida, a bacterial strain, were made using two-dimensional nuclear Overhauser enhancement correlation spectroscopy (NOESEY). The two-dimensional long-range heteronuclear correlation NMR technique was also utilized for the assignment of quaternary carbons in the naphthalene system. In addition, we describe methods for prediction of 13 C NMR chemical shifts of 2,6-and 2,7-disubstituted naphthalenes using topological approach. The method involves computation of molecular descriptors from topological representation of molecule, namely Wiener (W) and Szeged (Sz) indices. The results have shown that W and Sz indices can be successfully used for predicting 13 C NMR chemical shifts and that AE 13 Cn can be used as a molecular property which in turn can be modeled by both W and Sz indices successfully. #