title: Quantum mechanical study of the structure and spectroscopic (FT-IR, FT-Raman, 13C, 1H and UV), ﬁrst order hyperpolarizabilities, NBO and TD-DFT analysis of the 4-methyl-2-cyanobiphenyl.
abstract: The Fourier transform infrared (FT-IR) and FT-Raman of 4-methyl-2-cyanobiphenyl (4M2CBP) have been recorded and analyzed. The equilibrium geometry, bonding features and harmonic vibrational frequencies have been investigated with the help of density functional theory (DFT) method. The assignments of the vibrational spectra have been carried out with the help of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMFF). The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by the Gauge including atomic orbital (GIAO) method. The first order hyperpolarizability (β0) of this novel molecular system and related properties (β, α0 and Δα) of 4M2CBP are calculated using HF/6-311G(d,p) method on the finite-field approach. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The results show that charge in electron density (ED) in the σ* and π* antibonding orbitals and second order delocalization energies (E2) confirms the occurrence of intramolecular charge transfer (ICT) within the molecule. UV-vis spectrum of the compound was recorded and the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent density functional theory (TD-DFT) approach. Finally the calculations results were applied to simulated infrared and Raman spectra of the title compound which show good agreement with observed spectra.
authors.affiliation: Department of Physics (Science and Humanities), Sri Manakula Vinayagar Engg. College, Madagadipet, Puducherry 605 107, India.
authors.forename: S
authors.initials: S
authors.lastname: Sebastian
authors.forename: N
authors.initials: N
authors.lastname: Sundaraganesan
authors.forename: B
authors.initials: B
authors.lastname: Karthikeiyan
authors.forename: V
authors.initials: V
authors.lastname: Srinivasan
mesh_terms: D001713:Biphenyl Compounds / Q000737:chemistry*; D002247:Carbon Isotopes; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D009570:Nitriles / Q000737:chemistry*; D011522:Protons; D011789:Quantum Theory; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D014732:Vibration
chemical_list: D001713:Biphenyl Compounds; D002247:Carbon Isotopes; D009570:Nitriles; D011522:Protons; C557862:4-methyl-2-cyanobiphenyl; C010574:biphenyl