G3XMP2 INVESTIGATION OF AMINE INVERSION IN ANILINE AND ITS PARA ANILINES
Abstract
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 Objective: This article addresses the inversion dynamics of aniline and para-anilines by G3XMP2 theory and the effect of substituents on the inversion barrier.
Methods: The composite G3XMP2 method is used to evaluate the structural parameter, inversion barrier of aniline and para anilines.
Results: The investigation shows that the electron donating substituents increase the inversion barrier by mesomeric and hyper conjugative effects. Thus it favours a non-planar structure. Electron withdrawing substituents, however, promote the planar structure by strong inductive effects. Of all the ten substituents studied, amino group yields high inversion barrier and results in a non-planar configuration, while the nitroso group attains low inversion barrier and accounts for the planar structure of amine group.
Conclusion: The study concludes that the structure of amine group in aniline molecule is non-planar and its degree of non-planarity is heavily altered by the substituents.
Keywords: Inversion barrier, G3XMP2, Aniline, Amino group, Planarity
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Sponer J, Leszczynski J, Hobza P. Electronic properties, hydrogen bonding, stacking, and cation binding of DNA and RNA bases. Biopolymers 2001;61:3-31.
Wang S, Schaefer HF 3rd. The small planarization barriers for the amino group in the nucleic acid bases. J Chem Phys 2006;124:044303.
Lister DJ, Tyler JK, Hog JH, Larsen NW. The microwave spectrum, structure and dipole moment of aniline. J Mol Struct 1974;23(2):253 64.
Smith DA, Ulmer CW, Gilbert MJ. Structural studies of aromatic amines and the DNA intercalating compounds m-amsa and o-amsa: Comparison of MNDO, AM1 and PM3 to experimental and ab initio results. J Comp Chem 1992;13(5):640-50.
Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, et al. Pittsburgh PA, USA: Gaussian, Inc.; 2001.
Curtis LA, Redfern PC, Ragavachari K, Pople JA. Gaussian-3X (G3X) theory: Use of improved geometries, zero-point energies, and Hartree-Fock basis sets. J Chem Phys 2001;114(1):108-17.
Roussy G, Nonat A. Determination of the equilibrium molecular structure of inverting molecules by microwave spectroscopy: Application to aniline. J Mol Spectrosc 1986;118: 180-8.
Fukuyo M, Hirotsu K, Higuchi T. The structure of aniline at 252 K. Acta Crystallogr 1982;38:640-3.
Hargittai M, Hargittai I. On the molecular structure of methane sulfonyl chloride as studied by electron diffraction. J Chem Phys 1973;59:2513.
Yei E, Ryan PA, Chandrasekaran BK. Millimeter wave measurement and assignment of the rotational spectrum of aniline. J Mol Spec 2005;229:54-6.
Wang Y, Saebo S, Charles UP. Investigation of the structure and properties of ammeline, melamine, 2,4-diamino-1,3,5-triazine by ab initio calculations. J Org Chem 1993;58:3085-90.
Scott AP, Random L. Harmonic vibrational frequencies: An evaluation of Hartree-Fock moller-pleset quadrtic configuration intaraction density functional theory and semiempirical scale factors. J Phys Chem 1996;100:16502-13.
Larsen NW, Hansen EL, Nicolaisen FM. Far infrared investigation of aniline and 4-fluoroaniline in the vapour phase inversion and torsion of the amino group. Chem Phys Lett 1976;43:584-6.
Kydd RA, Kruger PJ. The far-infrared vapour phase spectra of aniline-ND2 and aniline- NHD Chem Phys Lett 1977;49:539-43.
Vaschetto ME, Retamal BA. Substituents effect on the electronic properties of aniline and oligoanilines. J Phys Chem A 1997;101:6945 50.
Vaschetto ME, Monkman AP, Springborg M. First-principles studies of some conducting polymers: PPP, PPy, PPV, PPyV, and PANI. J Mol Struct (Theochem)1999;468(3):181-91.
Sudlow KP, Woolf A. What is the geometry at trigonal nitrogen. J Chem Educ 1998;75(1):108-10.
Shishkin OV. Conformational flexibility of di and tetrahydropyrimidine rings in nucleic acid bases. An ab initio HF/6-31G** study. J Mol Struct 1998;447:1.
Hastie A, Lister DG, McNeil RL, Tyler JK. Substituent effects in benzene: The microwave spectrum of p-fluoroaniline. J Chem Soc D Chem Comm 1970;1970(2):108-9.
Hehre WJ, Random L, Pople JA. Inversion barriers in para-substituted anilines from ab-initio molecular-orbital theory. Chem Commun 1972;72:669-70.
Kydd RA, Kreuger PJ. The far infrared vapor phase spectra of the methylanilines. J Chem Phys 1980;72:280.
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