title: DFT analysis on the molecular structure, vibrational and electronic spectra of 2-(cyclohexylamino)ethanesulfonic acid.
abstract: The FTIR and FT-Raman spectra of 2-(cyclohexylamino)ethanesulfonic acid were recorded in the regions 4000-400 cm(-1) and 4000-50 cm(-1) respectively. The structural and spectroscopic data of the molecule in the ground state were calculated using Hartee-Fock and Density functional method (B3LYP) with the correlation consistent-polarized valence double zeta (cc-pVDZ) basis set and 6-311++G(d,p) basis set. The most stable conformer was optimized and the structural and vibrational parameters were determined based on this. The complete assignments were performed based on the Potential Energy Distribution (PED) of the vibrational modes, calculated using Vibrational Energy Distribution Analysis (VEDA) 4 program. With the observed FTIR and FT-Raman data, a complete vibrational assignment and analysis of the fundamental modes of the compound were carried out. Thermodynamic properties and Atomic charges were calculated using both Hartee-Fock and density functional method using the cc-pVDZ basis set and compared. The calculated HOMO-LUMO energy gap revealed that charge transfer occurs within the molecule. (1)H and (13)C NMR chemical shifts of the molecule were calculated using Gauge Including Atomic Orbital (GIAO) method and were compared with experimental results. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using Natural Bond Orbital (NBO) analysis. The first order hyperpolarizability (β) and Molecular Electrostatic Potential (MEP) of the molecule was computed using DFT calculations. The electron density based local reactivity descriptor such as Fukui functions were calculated to explain the chemical reactivity site in the molecule.
authors.affiliation: Department of Physics, Women's Christian College, College Road, Chennai 600006, TN, India. Electronic address: devi_renuga@yahoo.com.
authors.forename: T S
authors.initials: TS
authors.lastname: Renuga Devi
authors.affiliation: P.G. Department of Physics, Women's Christian College, College Road, Chennai 600006, TN, India; Department of Physics, Periyar University, Salem 636011, TN, India.
authors.forename: J
authors.initials: J
authors.lastname: Sharmi kumar
authors.affiliation: Department of Physics, C. Kandaswami Naidu College for Men in Anna Nagar East, Chennai 600102, TN, India.
authors.forename: G R
authors.initials: GR
authors.lastname: Ramkumaar
mesh_terms: D004583:Electrons; D019277:Entropy; D006358:Hot Temperature; D009682:Magnetic Resonance Spectroscopy; D008697:Methane / Q000737:chemistry; D008968:Molecular Conformation; D015394:Molecular Structure; D012984:Software; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D013654:Taurine / Q000031:analogs & derivatives* / Q000737:chemistry; D013816:Thermodynamics
chemical_list: C050927:2-(N-cyclohexylamino)ethanesulfonic acid; D013654:Taurine; D008697:Methane
keywords: CHES; FTIR; Fukui function; HOMO–LUMO; NMR