On the basicity and π-electron delocalization of ‘hexaazabenzene’ N6 – Quantum-chemical studies

Raczyńska, Ewa D.

doi:10.1016/j.comptc.2011.05.035

Cited by 20 publications

(17 citation statements)

References 50 publications

(34 reference statements)

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“…These variations influence π-electron delocalization in the ring (six atoms) and also in the whole tautomeric system (seven atoms including the exo N atom). In this paper, we quantitatively measured the changes of π-electron delocalization by means of the geometry based harmonic oscillator model of electron delocalization (HOMED) index [6, 7, 35, 45–48] which describes well any type of conjugation (π-π, n-π, and σ-π) possible in heteroatomic systems. This index was applied here to the DFT-calculated bond lengths.…”

Section: Resultsmentioning

confidence: 99%

“…The HOMED procedure has been described in detail in ref [46] and applied to various cyclic and acyclic π-electron systems containing heteroatoms [6, 7, 35, 45–48]. The HOMED index is based on the original harmonic oscillator model of aromaticity (HOMA) index [49, 50].…”

Section: Homed Indicesmentioning

confidence: 99%

“…The HOMA index reformulated in 1993 [51] seems to be inappropriate for π-electron delocalized systems containing heteroatoms. The main reason is a use of different measures of π-electron delocalization for the reference CC and CX bonds [6, 7, 35, 45–48]. The reformulated HOMA index can be solely applied for homoaromatics.…”

Section: Homed Indicesmentioning

confidence: 99%

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DFT studies on one-electron oxidation and one-electron reduction for 2- and 4-aminopyridines

2012

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Quantum-chemical calculations {DFT(B3LYP)/6-311+G(d,p)} were performed for all possible tautomers (aromatic and nonaromatic) of neutral 2- and 4-aminopyridines and their oxidized and reduced forms. One-electron oxidation has no important effect on the tautomeric preference for 2-aminopyridine. The amine tautomer is favored. However, oxidation increases the stability of the imine NH tautomer, and its contribution in the tautomeric mixture cannot be neglected. In the case of 4-aminopyridine, one-electron oxidation increases the stability of both the amine and imine NH tautomers. Consequently, they possess very close energies. As major tautomers, they dictate the composition of the tautomeric mixture. The CH tautomers may be considered as very rare forms for both neutral and oxidized aminopyridines. A reverse situation takes place for the reduced forms of aminopyridines. One-electron reduction favors the C3 atom for the labile proton for both aminopyridines. This may partially explain the origin of the CH tautomers for the anionic states of nucleobases containing the exo NH2 group.

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Section: Resultsmentioning

confidence: 99%

Section: Homed Indicesmentioning

confidence: 99%

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DFT studies on one-electron oxidation and one-electron reduction for 2- and 4-aminopyridines

2012

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“…A study of the aromaticity, using many criteria, used the series of benzene, mono, di and triazines as a test of the different criteria . Planar hexazine ( 80 ) is not stable but it is reportedly aromatic …”

Section: Introductionmentioning

confidence: 99%

“…[4] A study of the aromaticity, using many criteria, used the series of benzene, mono, di and triazines as a test of the different criteria. [5] Planar hexazine (80) is not stable [6][7][8] but it is reportedly aromatic. [7] Work on phosphorous six-membered rings is much more scarce, beyond the quoted review, [2] most works concentrated on P 6 .…”

Section: Introductionmentioning

confidence: 99%

A theoretical study of the properties of ninety‐two “aromatic” six‐membered rings including benzene, azines, phosphinines and azaphosphinines

Elguero

Alkorta

Elguero

2018

Heteroatom Chemistry

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Ninety‐two unsaturated hexagonal compounds (from benzene to hexaphosphinine, including azines and azaphosphinines) have been theoretically studied at DFT level, B3LYP/6‐311++G(d,p). Lone pair/lone pair repulsion between adjacent N atoms has been deduced using an empirical partition of the energy. Aromaticity based on magnetic criteria and on Bader analysis was studied finding that both criteria were almost orthogonal. The structure that are nonplanar or broken have been analyzed in function of their geometry or the fragments, respectively.

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Theoretical Prediction and Comprehensive Characterization of an All‐Nitrogenatomic Ring, Cyclo[18]Nitrogen (N₁₈)

2024

ChemPhysChem

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The cyclic molecule cyclo[18]carbon composed of 18 carbon atoms has been observed in condensed phase experiment in recent years and has attracted great attention. Through state‐of‐art quantum chemistry calculation, this study found that 18 nitrogen atoms can also form a macrocyclic system, cyclo[18]nitrogen (N18), though its lifetime is very short at room temperature and can only exist for a relatively long time at very low temperatures. We comprehensively theoretically studied properties of N18, including geometric configurations, thermal decomposition mechanism and rate, molecular dynamics behavior, energetic properties, vibrational and electronic spectra. We also discussed in depth the electronic structure of N18, including nature of the N‐N bonds, lone‐pairs, charge distribution characteristics, electronic delocalization, and aromaticity. This work is not only the first exploration of the macrocyclic N18 molecule, but also the first time to systematically examine a very long‐chain substance fully composed of nitrogen atoms in isolated state.

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On the basicity and π-electron delocalization of ‘hexaazabenzene’ N6 – Quantum-chemical studies

Cited by 20 publications

References 50 publications

DFT studies on one-electron oxidation and one-electron reduction for 2- and 4-aminopyridines

DFT studies on one-electron oxidation and one-electron reduction for 2- and 4-aminopyridines

A theoretical study of the properties of ninety‐two “aromatic” six‐membered rings including benzene, azines, phosphinines and azaphosphinines

Theoretical Prediction and Comprehensive Characterization of an All‐Nitrogenatomic Ring, Cyclo[18]Nitrogen (N₁₈)

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On the basicity and π-electron delocalization of ‘hexaazabenzene’ N6 – Quantum-chemical studies

Cited by 20 publications

References 50 publications

DFT studies on one-electron oxidation and one-electron reduction for 2- and 4-aminopyridines

DFT studies on one-electron oxidation and one-electron reduction for 2- and 4-aminopyridines

A theoretical study of the properties of ninety‐two “aromatic” six‐membered rings including benzene, azines, phosphinines and azaphosphinines

Theoretical Prediction and Comprehensive Characterization of an All‐Nitrogenatomic Ring, Cyclo[18]Nitrogen (N18)

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Product

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Theoretical Prediction and Comprehensive Characterization of an All‐Nitrogenatomic Ring, Cyclo[18]Nitrogen (N₁₈)