Are polarizabilities useful as aromaticity indices? Tests on azines, azoles, oxazoles and thiazoles

Doerksen, Robert J.; Steeves, Valerie; Thakkar, Ajit J.

doi:10.3233/jcm-2004-4318

Cited by 4 publications

(10 citation statements)

References 4 publications

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“…For example, the relative ordering of thiophene, pyrrole, furan, and the positional isomers as the three triazines, as well as the variations within given related systems like azines. 8 4.1. Azabenzenes.…”

Section: Resultsmentioning

confidence: 99%

“…The observed trends in the AIBICC values broadly satisfy the general expectations for the quantification of aromaticity. For example, the relative ordering of thiophene, pyrrole, furan, and the positional isomers as the three triazines, as well as the variations within given related systems like azines …”

Section: Resultsmentioning

confidence: 99%

“…With the five-membered heterocyclic rings thiophene, pyrrole, and furan, aza-substituted for CH, one gets thia-azoles, azoles, and oxa-azoles, respectively. The chemistry of azoles is important, because they form subunits of several biosystems and are studied experimentally and theoretically. ,, …”

Section: Resultsmentioning

confidence: 99%

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Quantification of Aromaticity of Heterocyclic Systems Using Interaction Coordinates

Dey

Manogaran

et al. 2018

J. Phys. Chem. A

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Recently, we proposed an aromaticity index based on interaction coordinates (AIBIC) ( J. Phys. Chem. A 2016 , 120 , 2894 - 2901 ). This index works well for the aromatic hydrocarbons. However, in the case of heterocyclic systems, the AIBIC overestimates the aromaticity indicating many of them to be more aromatic than benzene, which seems unlikely. Because of the differences in the electronegativity of the carbon and the other heteroatoms, the electron density is partially localized near the more electronegative atom(s) of the aromatic fragment. This localized electron density does not contribute to the aromaticity that is due to the delocalized electron density over the central ring. To account for this reduction in the delocalized electron density, a correction is introduced based on Pauling's electronegativity equation. When the corrected interaction coordinates are used in the computation of AIBIC, we get a new index-aromaticity index based on interaction coordinates corrected. This new index, when computed for a variety of heterocyclic systems, yields results in line with the expectations, and its usefulness in quantifying aromaticity appears to be very promising.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Quantification of Aromaticity of Heterocyclic Systems Using Interaction Coordinates

Dey

Manogaran

et al. 2018

J. Phys. Chem. A

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“…The most notable increase of about 29 % is observed in 2 . While not as suitable as anisotropy‐based indices of aromaticity, [64] polarizability‐based ones do reflect on structure stability [65] . Accordingly, an isotropic polarizability relative ordering for the series has been found to be 3 ≥ 2 > 4 > 5 > 7 > 6 > 8 > 9 > 1 , compared against a corresponding 3 > 4 > 5 ≥ 6 ≥ 2 > 7 > 8 > 9 > 1 ordering for anisotropic polarizability (Table 9S of SI).…”

Section: Resultsmentioning

confidence: 98%

N,N‐ and N,O‐6‐membered Ring peri‐Annelation in Naphthalene. Is it a Heteroring or merely a peri‐ Heterobridge?

Tzeli

Tsoungas

2021

ChemistrySelect

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The effect of peri‐fusion on the aromaticity of 6‐membered N−, O−, N,N−, N,N,N− and N,O‐doped naphthalene derivatives has been studied via NICS‐z, ‐xz, ‐xy, and ‐xyz scans employing DFT and MP2 calculations. The relative aromaticity of these structures was found to vary with the type of heteroring and the distance from the plane. Their corresponding ordering depends on the scan approaches. Accordingly, i) along the z axis at the center of the naphthalene B and C constituent rings, it is 1,8>2>7,9≫4>6, 5>3 (the most aromatic members are naphthalene and the N,O‐derivative 8), ii) along the x symmetry axis of naphthalene, it is 3>8,7>5>4>9>6>2>1 (the most aromatic one is a N‐derivative 3) and iii) along the z axis, on the xy plane, it is 6>1>8>9>2>5>7>3>4 at z=0.8 Å and 1>2>8>9>6>7>5>3>4 at 2.4 Å (the most aromatic ones are the N,N,N‐derivative 6 at 0.8 Å and naphthalene at 2.4 Å). Their relative magnetic anisotropy ordering remains virtually unaltered in all different approaches (z‐, xz‐, xy‐, and xyz‐scans), as does their aromaticity at z=2.4 Å. The σ component of the total density is dominant close to the plane while the π component picks up in significance with increasing distance from the plane. The peri‐fused ring appears to be a heteroring not just a heterobridge.

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“…Thakkar and his co-workers 45 critically analyzed the subject by comparing various aromaticity indices to the polarizability of the set of heterocyclic compounds. Their main conclusion is that none of the considered polarizability-based indices of aromaticity is entirely suitable.…”

Section: ■ Conclusionmentioning

confidence: 99%

Dynamic Polarizability and Higher-Order Electric Properties of Fluorene, Carbazole, and Dibenzofuran

et al. 2019

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Static electric properties, from the dipole moment to the second-hyperpolarizability tensor γ, of the 3membered, isoelectronic ring molecules, fluorene (FL), carbazole (CR), and dibenzofuran (DBF), have been calculated at various levels of approximation. The electron correlation effects have been included at the coupled-cluster (CC) level, using CCSD and CC2 versions of the method. DFT calculations with the CAM-B3LYP functional have also been performed, and the results are compared to the CC values. The electric property-tailored Pol basis set and its more compact Z3Pol version have been employed in all static calculations. Differences between dipole polarizability values computed at the Pol and Z3Pol bases have been found to be almost negligible. Therefore, all components of the frequency-dependent dipole polarizability tensor α(−ω;ω) have been determined at the CAM-B3LYP/Z3Pol level. Divergence occurring at electronic resonances has been eliminated using the complex polarization propagator (CPP) formalism, explicitly introducing an imaginary iΓ parameter to account approximately for the finite lifetime of the excited state. The imaginary part of the dipole polarizability Im α(−ω;ω) has been calculated for a wide range of external radiation energies up to 10 eV, and its maxima have been compared to the calculated vertical electronic excitation energies.

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Are polarizabilities useful as aromaticity indices? Tests on azines, azoles, oxazoles and thiazoles

Cited by 4 publications

References 4 publications

Quantification of Aromaticity of Heterocyclic Systems Using Interaction Coordinates

Quantification of Aromaticity of Heterocyclic Systems Using Interaction Coordinates

N,N‐ and N,O‐6‐membered Ring peri‐Annelation in Naphthalene. Is it a Heteroring or merely a peri‐ Heterobridge?

Dynamic Polarizability and Higher-Order Electric Properties of Fluorene, Carbazole, and Dibenzofuran

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