On the use of NICS criterion to evaluate aromaticity in heteroaromatics involving III and IV row main group elements

Amaran, Saieswari; Priyakumar, U. Deva; Sastry, G. Narahari

doi:10.1016/j.theochem.2003.08.130

Cited by 45 publications

(19 citation statements)

References 29 publications

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“…According to Sastry et al values we reported at the beginning: 1a (−12.8 ppm), 3a (−10.0 ppm), 5a (−12.4 ppm) and 7a (−11.4 ppm). [3,4] Our values are smaller but proportional to those of Sastry et al [3,4] (84%), and his 1/2a > 5/6a > 7/8a > 3/6a order is respected. The correlation values with σ p + are poor (R 2 ≤ 0.8; Krygowski et al noted the same trend for their set of monosubstituted benzenes).…”

Section: Nicscontrasting

confidence: 44%

“…Sastry et al have reported the NICS(0) and NICS(1) of the four parent compounds: 1a (−11.5 and −12.8 ppm), 3a (−10.0 and −10.0 ppm), 5a (−9.6 and −12.4 ppm) and 7a (−9.5 and −11.4 ppm), respectively. [3,4] Considering the more reliable NICS(1) values, the aromaticity decreases in the order of 1a > 5a > 7a > 3a, all of them being aromatic. Baldridge et al reported a comprehensive high-level (up to coupled cluster) theoretical study of all silabenzenes (from SiC 5 H 6 to Si 6 H 6 ).…”

Section: Introductionmentioning

confidence: 99%

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A theoretical NMR study of ortho and para-substituted benzenes compared with silabenzenes, pyridines and phosphabenzenes

Alkorta

Elguero

2010

Magn. Reson. Chem.

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The experimental spin-spin coupling constants (SSCCs) for 1,3- and 1,4-difluorobenzene have been determined anew, and found to be consistent with previously determined values. SSCCs for 1,2-, 1,3-, and 1,4-difluorobenzene have been analyzed by comparing them with the coupling constants computed using the second-order polarization propagator approximation (SOPPA) and the equation-of-motion coupled cluster singles and doubles method (EOM-CCSD). Eighty experimental values have been analyzed using SOPPA calculations, and a subset of 40 values using both SOPPA and EOM-CCSD approaches. One-bond coupling constants (1)J(C-C) and (1)J(C-F) are better described by EOM-CCSD, whereas one-bond (1)J(C-H) values are better described by SOPPA. An empirical equation is presented which allows for the prediction of unknown coupling constants from computed SOPPA values. A similar approach may prove useful for predicting coupling constants in larger systems.

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Section: Nicscontrasting

confidence: 44%

Section: Introductionmentioning

confidence: 99%

A theoretical NMR study of ortho and para-substituted benzenes compared with silabenzenes, pyridines and phosphabenzenes

Alkorta

Elguero

2010

Magn. Reson. Chem.

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“…18.36 ppm). Some inconsistencies in calculated NICS values are observed which can be attributed to the local effects [78] and/or the presence of heavy (row III) Se atom on the aromatic system [79]. This is in spite of the recent ambiguities reported for the NISC calculations when used as the sole aromaticity criterion [80].…”

Section: Aromaticitymentioning

confidence: 96%

On the selenepin/benzene selenide valence tautomerizations: electronic and steric effects at theoretical levels

2009

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Tautomerization in selenepin (1) benzene selenide (2) binary system is found to favor, 2, at HF, MP2, and B3LYP levels, using 6-311G* basis set. Electronic effects appear to have small effects on 1 2 equilibria and show little impact on the conformational ring inversions of 1, at the same levels. In contrast, steric effects effectively decrease DH values in an order inversely proportional to the size of the substituents employed (Me [ Et [ i-Pr). A possible Se extrusion is suggested to be the main reason why no 2 has ever been detected experimentally.

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“…2. In Table 1, the values (in parentheses) of some compounds had been calculated at the HF/6-31G (d) level [22]. In order to have a compare, the NICS values of benzene were calculated at the same condition.…”

Section: Nics and Ase Analysesmentioning

confidence: 99%

“…The purpose of this study was to obtain a consistent set of aromaticity values for six-numbered Nheteroatom compounds using NICS and the magnetic susceptibility isotropic criterions and to evaluate the correlative chemical characters of them. The NICS values of some compounds (61a, 62a, 63b, 63c) have been calculated at the center of the rings and 0.5 Å above the molecular plane by Saieswari [22] at the HF/6-31G* level, however, according to our knowledge, the present work which to systematic estimation the aromaticity in six-numbered N-heteroatom compounds has never be done.…”

Section: Introductionmentioning

confidence: 98%

The theoretical study of aromaticity in N-heteroatom compounds

Dong

Wang

et al. 2007

Struct Chem

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In this article, we used nucleus-independent chemical shifts (NICS), aromatic stabilization energies (ASE), and magnetic susceptibility isotropic, calculated with (density functional theory) B3LYP levels at the 6-311+G (d, p) basis set, to evaluate the aromaticity of a set of 12 six-member planar p-electron aromatic systems: mono-and multi-substituted benzenes by nitrogen atoms. NICS were calculated at the center of the rings, 0.5 Å and 1 Å above the molecular plane, and in order to reflect the p-electron effects, we compare the values of NICS(0.5). The result statistically revealed significant correlations among the above three criteria. The comparison result was obtained as benzene > mono-nitrogen benzene > di-nitrogen benzene > tri-nitrogen benzene > tetra-nitrogen benzene > penta-nitrogen benzene.

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On the use of NICS criterion to evaluate aromaticity in heteroaromatics involving III and IV row main group elements

Cited by 45 publications

References 29 publications

A theoretical NMR study of ortho and para-substituted benzenes compared with silabenzenes, pyridines and phosphabenzenes

A theoretical NMR study of ortho and para-substituted benzenes compared with silabenzenes, pyridines and phosphabenzenes

On the selenepin/benzene selenide valence tautomerizations: electronic and steric effects at theoretical levels

The theoretical study of aromaticity in N-heteroatom compounds

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