Multicenter bond indices as a measure of aromaticity

Giambiagi, Mario; Silva, Cassia D. dos Santos; Figueiredo, Aloysio Paiva de

doi:10.1039/b002009p

Cited by 320 publications

(353 citation statements)

References 58 publications

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“…Lately aromaticity measures based on the electronic structure of molecules are becoming popular, and several research groups have contributed to the issue by providing new aromaticity indices. Among others we can mention the I ring [36] of Giambiagi et al, the Six Center Index (SCI) [37] of Bultinck and coworkers, the θ of Matta, [38] the PDI of Poater et al [39] or the FLU of Matito et al [40,41]; for recent reviews see Refs. [42] and [43].…”

Section: Theorymentioning

confidence: 99%

Performance of 3D‐space‐based atoms‐in‐molecules methods for electronic delocalization aromaticity indices

et al. 2010

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Several denitions of an atom in a molecule (AIM) in three dimensional space, including both fuzzy and disjoint domains, are employed to calculate electron sharing indices (ESI) and related electronic aromaticity measures, namely Iring and multicenter indices (MCI), for a wide set of cyclic planar aromatic and non-aromatic molecules of dierent ring size. The results obtained using the recent iterative Hirshfeld scheme are compared to those derived from the classical Hirshfeld method and from Bader's quantum theory of atoms in molecules. For bonded atoms all methods yield ESI values in very good agreement, especially for C-C interactions. In the case of non-bonded interactions there are relevant deviations, particularly between fuzzy and QTAIM schemes. These discrepancies directly translate into signicant dierences in the values and the trends of the aromaticity indices. In particular, the chemically expected trends are more consistently found when using disjoint domains. Careful examination of the underlying eects reveals the dierent reasons why the aromaticity indices investigated give the expected results for binary divisions of three dimensional space.

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Section: Theorymentioning

confidence: 99%

Performance of 3D‐space‐based atoms‐in‐molecules methods for electronic delocalization aromaticity indices

et al. 2010

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“…21 The same expression applied to a molecular ring was named I ring and used to account for aromaticity 22 I ring (A ) = 2 n−1…”

Section: Multicenter Indicesmentioning

confidence: 99%

An electronic aromaticity index for large rings

Matito

2016

Phys. Chem. Chem. Phys.

143

139

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We introduce a new electronic aromaticity index, AV1245, consisting in the average of the 4-center MCI values along the ring that keep a positional relationship of 1,2,4,5. AV1245 measures the extent of transferability of the delocalized electrons between bonds 1-2 and 4-5, which is expected to be large in conjugated circuits and, therefore, in aromatic molecules. A new algorithm for the calculation of MCI for large rings is also introduced and used to produce the data for the calibration of the new aromaticity index. AV1245 does not rely on reference values, does not suffer from large numerical precision errors, and it does not present any limitation on the nature of atoms, the molecular geometry or the level of calculation. It is a size-extensive measure with a small computational cost that grows linearly with the number of ring members. Therefore, it is specially suitable to study the aromaticity of large molecular rings as those occurring in belt-shaped Möbius structures or porphyrins.

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“…10 Among all the ways to quantify aromaticity through the ''ground-state'' criteria (energetic, structural, and electronic), there are descriptors that have gained enormous recognition and wide acceptance: the aromatic stabilization energy (ASE), 2 harmonic oscillator model of aromaticity (HOMA), [11][12][13] and different types of the multicenter delocalization indices (MCDI). [14][15][16][17][18] In turn, one of the most popular aromaticity descriptors based on the response properties is the nucleusindependent chemical shift (NICS) and its various derivatives. 4,19,20 Despite the unquestionable success and popularity of these aromaticity indices, some of their imperfections still cuts back their applicability to relatively small and simple systems.…”

Section: Introductionmentioning

confidence: 99%

The electron density of delocalized bonds (EDDB) applied for quantifying aromaticity

Szczepanik

Andrzejak

Dominikowska

et al. 2017

Phys. Chem. Chem. Phys.

164

145

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In this study the recently developed electron density of delocalized bonds (EDDB) is used to define a new measure of aromaticity in molecular rings. The relationships between bond-length alternation, electron delocalization and diatropicity of the induced ring current are investigated for a test set of representative molecular rings by means of correlation and principal component analyses involving the most popular aromaticity descriptors based on structural, electronic, and magnetic criteria. Additionally, a qualitative comparison is made between EDDB and the magnetically induced ring-current density maps from the ipsocentric approach for a series of linear acenes. Special emphasis is given to the comparative study of the description of cyclic delocalization of electrons in a wide range of organic aromatics in terms of the kekulean multicenter index KMCI and the newly proposed EDDB k index.

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Multicenter bond indices as a measure of aromaticity

Cited by 320 publications

References 58 publications

Performance of 3D‐space‐based atoms‐in‐molecules methods for electronic delocalization aromaticity indices

Performance of 3D‐space‐based atoms‐in‐molecules methods for electronic delocalization aromaticity indices

An electronic aromaticity index for large rings

The electron density of delocalized bonds (EDDB) applied for quantifying aromaticity

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