The experimental and computational study on the IR spectra and structure of pyridine-3-carboxamide (nicotinamide)-d0 and -d2

Velcheva, Evelina A.; Daskalova, Lalka I.

doi:10.1016/j.molstruc.2005.01.063

Cited by 20 publications

(10 citation statements)

References 31 publications

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“…The absence of negative frequencies or negative eigenvalues of the second‐derivative matrix confirmed that the stationary points correspond to global minima on the PEHS 27. The use of 6‐31+G( d , p ) basis sets in both ab initio and DFT computations has recently resulted in better or equally good structural predictions compared with other basis sets for both molecules 20, 21, 26, 30–34 and/or anions 34–38. All the computations were performed on a Pentium 2 PC.…”

Section: Computationsmentioning

confidence: 92%

Computational study of energies and structures of 2,4,6‐pyrimidinetrione and its anions

Daskalova

Binev

2005

Int J of Quantum Chemistry

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Energies and structures of 2,4,6-pyrimidinetrione, its anion, dianion, and trianion have been studied by means of ab initio and density functional computations. According to these studies, the most stable among the molecular tautomers is the triketo form, followed by the 6-hydroxy tautomer, in full agreement with earlier theoretical results and with experimental data on the tautomeric equilibrium. The deprotonation energy of 1345.24 kJ mol Ϫ1 calculated for 2,4,6-pyrimidinetrione, corresponds to a moderately strong COH acid, in accordance with its experimental pK a 1 ϭ 8.4 (solvent dimethylsulfoxide). The calculated structural changes, caused by the molecule 3 monoanion conversion, are in good agreement with those found experimentally. Energy and structural changes, worked by both anion 3 dianion and dianion 3 trianion conversions, have also been computed and discussed.

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Section: Computationsmentioning

confidence: 92%

Computational study of energies and structures of 2,4,6‐pyrimidinetrione and its anions

Daskalova

Binev

2005

Int J of Quantum Chemistry

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“…The latter result should be considered a very good one, as the frequency shifts are more sensitive, hence more informative than the frequencies themselves for estimating the accuracy of the computations [25]. For example, the corresponding ratio value in the case of nicotinamide-d 0 and -d 2 was found to be essentially large (i.e., worse), 18.3% [25].…”

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confidence: 91%

IR spectral and structural studies of 4‐aminobenzenesulfonamide (sulfanilamide)‐d₀, ‐d₄, and ‐¹⁵N, as well as their azanions: Combined DFT B3LYP/experimental approach

Popova

Georgieva

Petrov

et al. 2006

Int J of Quantum Chemistry

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ABSTRACT:The infrared (IR) spectra of sulfanilamide 1 and of its azanion (counter ion Na ϩ ) 2 have been measured in dimethyl sulfoxide (DMSO) solutions. The density functional theory (DFT) B3LYP 6-31ϩϩG(d,p) computations performed adequately describe the experimental spectroscopic data, including the corresponding frequency isotopic shifts. In agreement between theory and experiment, the conversion of sulfanilamide 1 into azanion 2 results in strong frequency decreases of the asymmetrical and symmetrical vibrations of the SO 2 group: predicted 122 cm Ϫ1 , measured 140 cm Ϫ1 in solution (total values), as well as in other essential IR spectral changes. According to the computations, the strongest changes in the steric structure take place at and next to the azanionic center. The new (azanionic) charge is distributed, as follows: 0.08e Ϫ , 0.23e Ϫ , and 0.12e Ϫ are delocalized over the amino, phenylene, and sulfonic groups, respectively, and 0.57e Ϫ of it remain localized at the azanionic center.

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“…See also the Refs. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] and [22][23][24] in the paper honoring Aldo Domenicano, the pioneer of the accurate determination of substituent effects in benzene derivatives [48]. The r-acceptors increase the ipso bond angle, e.g., a ipso = 123.4(2)°in fluorobenzene [49], while r-donors, p-donors, and p-acceptors [47] decrease this bond angle, e.g., a ipso = 119.0(2)°in aniline [50].…”

Section: Resultsmentioning

confidence: 99%

“…They possess a variety of pharmacological activity; among others, analgesic [1,2], antitumor [3,4], prokinetic [5], and neuroleptic [6]. Owing to medical applications and theoretical importance, extensive studies have dealt with benzamide and its derivatives [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

“…The molecular structures of heterocyclic aromatic amides have also been studied, viz., picolinamide [17], nicotinamide [17,18], and isonicotinamide [17], by DFT calculations. Comparison of X-ray diffraction [19], neutron diffraction (ND) [20], and gas-phase electron diffraction (GED) [21] results on nicotinamide has provided evidence of intermolecular hydrogen bonding in its crystal.…”

Section: Introductionmentioning

confidence: 99%

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Equilibrium molecular structure of benzamide from gas-phase electron diffraction and theoretical calculations

2015

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The molecule structure of benzamide has been determined in the gas phase by electron diffraction using results from quantum chemical calculations for constraints in the analysis. The root-mean-square amplitudes of vibration and harmonic shrinkage corrections were calculated taking into account nonlinear relations between Cartesian and internal vibrational coordinates at the level of first-order perturbation theory. The corresponding r h1 structure agrees well with the results of B3LYP/cc-pVTZ calculations. To take into account vibrational effects, the corrections to the experimental r a bond lengths, the values of the differences r e -r a were obtained using quadratic and cubic force constants from ab initio calculations at the MP2/cc-pVTZ level of theory). The equilibrium structure from the experiment agrees well with the results of the ab initio calculations. The following structural parameters were obtained (bond lengths in Angstroms and bond angles in degrees with 3r in parentheses): r(C=C) av = 1.392(1), r(C-C) = 1.502(4), r(C-N) = 1.367(1), r(C=O) = 1.224 (3), r(C-H) = 1.084(4), \C6C1C2 = 119.8, \CCN = 116.8(10), \CCO = 120.8(11), \C2C1C7O = 18.4(27). The C=O bond is shorter by 0.02 Å , and the C-N bond is longer by 0.03 Å than the corresponding bonds in the crystal. These differences are ascribed to the effect of intermolecular hydrogen bonding on the structure in the crystal.

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The experimental and computational study on the IR spectra and structure of pyridine-3-carboxamide (nicotinamide)-d0 and -d2

Cited by 20 publications

References 31 publications

Computational study of energies and structures of 2,4,6‐pyrimidinetrione and its anions

Computational study of energies and structures of 2,4,6‐pyrimidinetrione and its anions

IR spectral and structural studies of 4‐aminobenzenesulfonamide (sulfanilamide)‐d₀, ‐d₄, and ‐¹⁵N, as well as their azanions: Combined DFT B3LYP/experimental approach

Equilibrium molecular structure of benzamide from gas-phase electron diffraction and theoretical calculations

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The experimental and computational study on the IR spectra and structure of pyridine-3-carboxamide (nicotinamide)-d0 and -d2

Cited by 20 publications

References 31 publications

Computational study of energies and structures of 2,4,6‐pyrimidinetrione and its anions

Computational study of energies and structures of 2,4,6‐pyrimidinetrione and its anions

IR spectral and structural studies of 4‐aminobenzenesulfonamide (sulfanilamide)‐d0, ‐d4, and ‐15N, as well as their azanions: Combined DFT B3LYP/experimental approach

Equilibrium molecular structure of benzamide from gas-phase electron diffraction and theoretical calculations

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IR spectral and structural studies of 4‐aminobenzenesulfonamide (sulfanilamide)‐d₀, ‐d₄, and ‐¹⁵N, as well as their azanions: Combined DFT B3LYP/experimental approach