Density functional and post Hartree-Fock equilibrium geometries, potential energy surface and vibrational frequencies for methylamine

Csonka, Gábor I.; Sztraka, L.

doi:10.1016/0009-2614(94)01504-o

Cited by 19 publications

(7 citation statements)

References 29 publications

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“…Note that the B3LYP imaginary frequencies differ no more than 80 cm -1 from the CCSD(T)/cc-pVTZ results. All geometric parameters calculated using B3LYP/cc-pVQZ are, in general, in good agreement with the CCSD(T) results and also with previous theoretical calculations [7][8][9][10]13,14 and experimental data. [2][3][4] We have also carried out the IRC calculations using the B3LYP/ cc-pVTZ method and the results confirm that the first-order inversion transition state and the rotation transition state connect to the ground state, as already shown by Kim and Zeroka 13 using a more complete two-dimensional potential energy surface.…”

Section: Resultssupporting

confidence: 87%

“…112.4 A (1,4,11) 110.3 A (1,4,12); A (1,4,13) 112.4 A (1,2,5) 110.1 A (1,3,10); A (1,3,9) 112.8 A (1,3,8 1.093 R (2,6) (2,7)…”

Section: Supplementary Informationmentioning

confidence: 99%

“…106.8 A (1,3,8) (1,4,11) 113.3 A (1,3,9) (1,4,13) 109.8 A (1,3,10) (1,4,12) 110.1 A (9,3,10) (12,4,13) 107.7 A (11,4,13) (8,3,9) 108.0 A (11,4,12) (8,3,10) 107.8…”

Section: Supplementary Informationmentioning

confidence: 99%

“…[1][2][3][4][5][6][7] Methylamine is considered a small molecule from the theoretical point of view, therefore it is appropriate to be studied using high level theoretical quantum chemical methodologies, having received many contributions. [7][8][9][10][11][12][13][14] Lee et al 8 investigated the origin of the structural stability of methylamine concluding that the stereo electronic effect is the major interaction force affecting its stability. Csonka and Sztraka 9 using density functional and post-HartreeFock methodologies showed that the density functional BP86/6-311G(d) method provides reliable results for geometry and vibrational frequencies, as compared with the experimental results.…”

Section: Introductionmentioning

confidence: 99%

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A theoretical study of the inversion and rotation barriers in Methyl-substituted Amines

Nascimento¹,

Pelegrini²,

Ferrão³

et al. 2011

J. Braz. Chem. Soc.

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Barreiras de energia para os movimentos de inversão e rotação das moléculas metilamina, dimetilamina e trimetilamina foram calculadas usando a metodologia CCSD(T)//B3LYP com os conjuntos de funções de base de Dunning, cc-pVTZ, cc-pVQZ e cc-pCVTZ. O procedimento de extrapolação para o conjunto de base completa (complete basis set, CBS) e os efeitos da correlação dos elétrons do caroço também foram incluídos nos cálculos das barreiras de energia. Nossos melhores resultados estão em excelente concordâncias com os dados experimentais, indicando que a metodologia utilizada é recomendada para a predição exata de propriedades estruturais e de barreiras de energia de outros sistemas moleculares.Barrier heights of the internal rotation and inversion motions of methylamine, dimethylamine and trimethylamine molecules were calculated with the CCSD(T)//B3LYP methodology in combination with the cc-pVTZ, cc-pVQZ, and cc-pCVTZ basis sets of Dunning. The complete basis set (CBS) extrapolation procedure and core-valence (CV) correlation effects are also examined to the barrier heights. Our best estimate results (CCSD(T)/CBS+CV//B3LYP/cc-pVQZ) are in very good agreement with the experimental data, indicating the use of this methodology to provide accurate predictions of structures and barrier heights for other systems. Keywords: energy barriers, methylamine, dimethylamine, trimethylamine, CCSD//B3LYP IntroductionThe methyl-substituted amines, methylamine (CH 3 NH 2 ), dimethylamine [(CH 3 ) 2 NH], and trimethylamine [(CH 3 ) 3 N] form an interesting group of molecules which are important in organic syntheses and biological processes, as well as they are efficient corrosion inhibitors of aluminum. Beyond their technological importance, these species are rich in structural features presenting large amplitude internal motions, rotation of the methyl groups and internal inversion of the amino group.Methylamine has been extensively studied by experimentalists in which its internal rotation and inversion barrier heights were determined using microwave (MW), infrared (IR) and electron diffraction (ED) experiments. [1][2][3][4][5][6][7] Methylamine is considered a small molecule from the theoretical point of view, therefore it is appropriate to be studied using high level theoretical quantum chemical methodologies, having received many contributions. [7][8][9][10][11][12][13][14] Lee et al. 8 investigated the origin of the structural stability of methylamine concluding that the stereo electronic effect is the major interaction force affecting its stability. Csonka and Sztraka 9 using density functional and post-HartreeFock methodologies showed that the density functional BP86/6-311G(d) method provides reliable results for geometry and vibrational frequencies, as compared with the experimental results. Smeyers and Villa 10 discussed the influence of the zero-point energy correction to the rotation and inversion motions based on the MP2 results, and During and Zheng 7 calculated these motions barriers using B3LYP and MP2 methods. Recently,...

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Section: Resultssupporting

confidence: 87%

“…112.4 A (1,4,11) 110.3 A (1,4,12); A (1,4,13) 112.4 A (1,2,5) 110.1 A (1,3,10); A (1,3,9) 112.8 A (1,3,8 1.093 R (2,6) (2,7)…”

Section: Supplementary Informationmentioning

confidence: 99%

“…106.8 A (1,3,8) (1,4,11) 113.3 A (1,3,9) (1,4,13) 109.8 A (1,3,10) (1,4,12) 110.1 A (9,3,10) (12,4,13) 107.7 A (11,4,13) (8,3,9) 108.0 A (11,4,12) (8,3,10) 107.8…”

Section: Supplementary Informationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A theoretical study of the inversion and rotation barriers in Methyl-substituted Amines

Nascimento¹,

Pelegrini²,

Ferrão³

et al. 2011

J. Braz. Chem. Soc.

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show abstract

“…There are several reported experimental inversion barriers ranging from 20.19 to 24.89 kJ/mol 9–11. Calculated rotation barriers reported in the literature range from 8.10 to 9.81kJ/mol 12–14. Calculated second‐order inversion barriers in the literature range from 20.30 to 24 kJ/mol 12–15.…”

Section: Introductionmentioning

confidence: 99%

Internal‐rotation and inversion potential energy surfaces for methylamine and methylphosphine

Kim

Zeroka

2007

Int J of Quantum Chemistry

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Using the HF, MP2, and DFT methods with a 6-311G** basis set, we examine the internal-rotation and inversion of the amino and phosphino groups in methylamine and methylphosphine. The resulting energy surfaces are reported as a function of rotation and inversion descriptors. Both surfaces are characterized by several special points: three minimum energy states, three first-order internal-rotation transition states, six first-order inversion transition states, and six second-order inversion transition states. The MP2 method gave better agreement with experiment. For methylamine, the MP2 energy barrier for internal-rotation is 8.73 kJ/mol; for firstorder inversion it is 22.80 kJ/mol and for second-order inversion it is 22.41 kJ/mol. For methylphosphine, the MP2 energy barriers are 7.53, 149.88, and 149.65 kJ/mol, respectively. The energy barriers include ZPE correction contributions. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem 108: 974 -982, 2008

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Theoretical study of intramolecular hydrogen bonding and molecular geometry of 2-trifluoromethylphenol

et al. 1996

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Density functional and post Hartree-Fock equilibrium geometries, potential energy surface and vibrational frequencies for methylamine

Cited by 19 publications

References 29 publications

A theoretical study of the inversion and rotation barriers in Methyl-substituted Amines

A theoretical study of the inversion and rotation barriers in Methyl-substituted Amines

Internal‐rotation and inversion potential energy surfaces for methylamine and methylphosphine

Theoretical study of intramolecular hydrogen bonding and molecular geometry of 2-trifluoromethylphenol

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