Ueber das Benzol und die Säuren der Oel‐ und Talgarten

Mitscherlich, E.

doi:10.1002/jlac.18340090103

Cited by 28 publications

(13 citation statements)

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“…Another conflicting case of NICS' performance is [2,2]paracyclophane, in which the NICS predicted decrease of local aromaticity of the stacked rings was not real, but caused by the coupling of the magnetic fields generated by these two rings. 165 The same problem was experienced when the local aromaticity of a series of polyfluorene compounds with increasing number of -stacked layers was analysed.…”

Section: Discrepancy With Magnetic Measure Of Aromaticitymentioning

confidence: 99%

“…This is the case of benzene, but also of triplet C5H5 + , C60 10+ , Al4 2-or closo borane clusters like B6H6 2-. The closed-shell or same-spin half-filled electronic structure is the origin of several rules of aromaticity such as the 4n+2 Hückel, 9 4n Baird, 15 2n+2 Wade-Mingos, 27, 28 2(n+1) 2 Hirsch 29 or the 2n 2 +2n+1 30 rules. This particular electronic structure of aromatic species explains their substantial energetic stabilisation and, consequently, their low reactivity.…”

Section: Introductionmentioning

confidence: 99%

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Quantifying aromaticity with electron delocalisation measures

et al. 2015

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Aromaticity cannot be measured directly by any physical or chemical experiment because it is not a well-defined magnitude. Its quantification is done indirectly from the measure of different properties that are usually found in aromatic compounds such as bond length equalisation, energetic stabilisation, and particular magnetic behaviour associated with induced ring currents. These properties have been used to set up the myriad of structural-, energetic-and magnetic-based indices of aromaticity known to date. Cyclic delocalisation of mobile electrons in two or three dimensions is probably one of the key aspects that characterise aromatic compounds. However, it has not been until the last decade that electron delocalisation measures have been widely employed to quantify aromaticity. Some of these new indicators of aromaticity such as the PDI, FLU, ING, and INB were defined in our group. In this paper, we review the different existent descriptors of aromaticity that are based on electron delocalisation properties, we compare their performance with indices based on other properties, and we summarise a number of applications of electronic-based indices for the analysis of aromaticity in interesting chemical problems.2

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Section: Discrepancy With Magnetic Measure Of Aromaticitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantifying aromaticity with electron delocalisation measures

et al. 2015

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“…Column chromatography with 50% dichloromethane in hexanes, then dichloromethane gave product 2, 2 ′ ,6, 6 ′ -tetrafluoroazobenzene (113 mg, 11%). 1 H NMR (300 MHz, CDCl 3 ) δ: 7.45-7.28 (m, 2H), 7.13-6.98 (m, 4H). 13…”

Section: Experimental and Computational Methodsmentioning

confidence: 99%

Negative ion properties of trans 2,2′,6,6′-tetrafluoroazobenzene: Experiment and theory

Rezaee

Wang²,

Zhang³

et al. 2015

The Journal of Chemical Physics

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Chemical bonding and the electronic structure of the trans 2,2',6,6'-tetrafluoroazobenzene negative ion have been studied using collision-induced dissociation as well as photodetachment-photoelectron spectroscopy and the experimental results for different properties were compared with the corresponding values calculated using ab initio quantum chemistry methods. The trans 2,2',6,6'-tetrafluoroazobenzene anion was prepared by atmospheric pressure chemical ionization for the collision induced dissociation (CID) experiment and through thermal electron attachment in the photodetachment-photoelectron spectroscopy experiments. The adiabatic electron affinity of trans 2,2',6,6'-tetrafluoroazobenzene was measured to be 1.3 ± 0.10 eV using 355 nm, 488 nm, and 532 nm photodetachment photons and the vertical detachment energy was measured to be 1.78 ± 0.10 eV, 2.03 ± 0.10 eV, and 1.93 ± 0.10 eV, respectively. The adiabatic electron affinity was calculated employing different ab initio methods giving values in excellent agreement with experimental results. Energy resolved collision induced dissociation experiment study of the precursor anion resulted in 1.92 ± 0.15 eV bond dissociation energy for the collision process yielding [C6H3F2](-) fragment ion at 0 K. Calculations using different ab initio methods resulted in a bond dissociation energy ranging from 1.79 to 2.1 eV at 0 K. Two additional CID fragment ions that appear at higher energies, [C6H2F](-) and [C6H](-), are not results of a single bond cleavage. The occurrence of [C6H](-) is of particular interest since it is the first anion to be observed in the interstellar medium.

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“…Em 1834, Eilhard Mitscherlich também realizou uma síntese do benzeno partindo do ácido benzóico. 32 Nesta preparação, o aquecimento de ácido benzóico na presença de "cal virgem" produziu o benzeno (destilado do meio reacional) e carbonato de cálcio -calcário (Esquema 2).…”

Section: Evolução Histórica Do Conceito De Aromaticidadeunclassified

Aromaticidade: evolução histórica do conceito e critérios quantitativos

Caramori

Oliveira

2009

Quím. Nova

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Recebido em 4/8/08; aceito em 26/2/09; publicado na web em 28/7/09 AROMATICITY: HISTORICAL EVOLUTION OF THE CONCEPT AND QUANTITATIVE CRITERIA. In this paper the evolution of the concept of aromaticity is discussed. It considers not only historical aspects of the aromaticity concept but also the different criteria (theoretical and experimental) that have appeared to explain the properties of the aromatic compounds. The topics range from the isolation of benzene by Faraday (1825) until the modern criteria based on geometries, magnetic properties, resonance energy (RE), aromatic stabilization energy (ASE), topological analyses, and others. A chronological separation of issues concerning aromaticity was made, splitting the definitions before and after the appearance of the quantum chemistry. This work reviews the concept of aromaticity.

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Ueber das Benzol und die Säuren der Oel‐ und Talgarten

Cited by 28 publications

References 0 publications

Quantifying aromaticity with electron delocalisation measures

Quantifying aromaticity with electron delocalisation measures

Negative ion properties of trans 2,2′,6,6′-tetrafluoroazobenzene: Experiment and theory

Aromaticidade: evolução histórica do conceito e critérios quantitativos

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