FT-IR, UV spectroscopic and DFT quantum chemical study on the molecular conformation, vibrational and electronic transitions of 2-aminoterephthalic acid

Department of Physics, Afyon Kocatepe University, 03040 Afyonkarahisar, Turkey
Journal of Molecular Structure (Impact Factor: 1.6). 10/2010; 982:22-27. DOI: 10.1016/j.molstruc.2010.07.033

ABSTRACT In this work, the molecular conformation, vibrational and electronic analysis of 2-aminoterephthalic acid are presented for the ground state using FT-IR experimental technique and density functional theory (DFT) employing B3LYP exchange correlation functional with the 6-311++G(d,p) basis set. FT-IR spectrum was recorded in the region of 400–4000 cm−1. The ultraviolet absorption spectrum of studied compound that dissolved in ethanol was examined in the range of 190–450 nm. The complete assignments of fundamental vibrations were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. Optimized structure of title compound was interpreted and compared with the earlier reported experimental values of a similar compound. A study on the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach.

  • [Show abstract] [Hide abstract]
    ABSTRACT: A highly selective and robust catalyst based on Pt nanoclusters (NCs) confined inside the cavities of an amino-functionalized Zr-terephthalate metal–organic framework, UiO-66-NH2 was developed. The Pt NCs are monodisperse and confined in the cavities of UiO-66-NH2 even at 10.7 wt% Pt loading. This confinement was further confirmed by comparing the catalytic performance of Pt NCs confined inside and supported on the external surface of the MOF in the hydrogenation of ethylene, 1-hexene, and 1,3-cyclooctadiene. The benefit of confining Pt NCs inside UiO-66-NH2 was also demonstrated by evaluating their performance in the chemoselective hydrogenation of cinnamaldehyde. We found that both high selectivity to cinnamyl alcohol and high conversion of cinnamaldehyde can be achieved using the MOF-confined Pt nanocluster catalyst, while we could not achieve high cinnamyl alcohol selectivity on Pt NCs supported on the external surface of the MOF. The catalyst can be recycled ten times without any loss in its activity and selectivity.To confirm the stability of the recycled catalysts, we conducted kinetic studies for the first 20 hours of reaction during four recycle runs on the catalyst. Both the conversion and selectivity are almost overlapping for the four runs, which indicates the catalyst is very stable under the employed reaction conditions.
    ACS Catalysis 03/2014; 4:1340. · 7.57 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The FTIR and FT-Raman spectra of 2-mercapto-4(3H) quinazolinone have been recorded in the region 4000-450 and 4000-100cm(-1), respectively. The optimized geometry, frequency and intensity of the vibrational bands of 2-mercapto-4(3H) quinazolinone (2MQ) were obtained by the density functional theory (DFT) using 6-311++G(d,p) basis set. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FTIR and FT-Raman spectra. The (1)H and (13)C nuclear magnetic resonance chemical shifts of the molecule were also calculated using the gauge independent atomic orbital (GIAO) method. The theoretical UV-VIS spectrum of the compound and the electronic properties, such as HOMO (highest occupied molecular orbital) and LUMO (lowest occupied molecular orbital) energies were performed by time-dependent DFT (TD-DFT) approach. The change in electron density (ED) in the σ(*) antibonding orbitals and stabilization energies E((2)) have been calculated by natural bond (NBO) analysis, to give clear evidence of stabilization originating in the hyper conjugation of hydrogen-bonded interactions. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecule has been obtained by mapping electron density isosurface with molecular electrostatic potential (MESP).
    Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 04/2014; · 2.13 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The molecular structure and vibrations of 5-[(3-methylphenyl) (phenyl) amino] isophthalic acid (MePIFA) were investigated by infrared and Raman spectroscopies, UV-Vis, (1)H and (13)C NMR spectroscopic techniques and NBO analysis. FT-IR, FT-Raman and dispersive Raman spectra were recorded in the solid phase. (1)H and (13)C NMR spectra and UV-Vis spectrum were recorded in DMSO solution. HOMO-LUMO analysis and molecular electrostatic potential (MEP) analysis were performed. The theoretical calculations for the molecular structure and spectroscopies were performed with DFT (B3LYP) and 6-311G(d,p) basis set calculations using the Gaussian 09 program. After the geometry of the molecule was optimized, vibration wavenumbers and fundamental vibration wavenumbers were assigned on the basis of the potential energy distribution (PED) of the vibrational modes calculated with VEDA 4 program. The total (TDOS), partial (PDOS) density of state and overlap population density of state (OPDOS) diagrams analysis were made using GaussSum 2.2 program. The results of theoretical calculations for the spectra of the title compound were compared with the observed spectra.
    Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 05/2014; 133C:307-317. · 2.13 Impact Factor


Available from
May 16, 2014