Kekulen

Structural formula
General
Surname	Kekulen
other names	[12] coronaphs
Molecular formula	C 48 H 24
External identifiers / databases
PubChem	5460755
Wikidata	Q3119689
properties
Molar mass	600.70 g mol −1
safety instructions
GHS hazard labeling ; no classification available
GHS hazard labeling ; no classification available
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Kekulen is a polycyclic aromatic hydrocarbon and circulen . Its structural formula is C ₄₈ H ₂₄ . The first synthesis was achieved in 1978 by Heinz A. Staab and François Diederich . Kekulen is named after August Kekulé , who discovered the structure of benzene .

Kekulen is a very poorly soluble and high-melting compound. 10 mg dissolve in 350 ml of boiling 1-methylnaphthalene at 245 ° C. and 1 mg in boiling 1,2,4-trichlorobenzene at 214 ° C. Under nitrogen, it begins to decompose from 620 ° C without melting.

X-ray structural analysis and NMR spectroscopy suggest that Kekulen is not entirely aromatic, but that aromatic rings and double bonds alternate. Ultimately, this was supported by AFM .

literature

R. Peter, W. Jenny: 250. Higher, condensed ring systems. Part 1: Investigations in the [10] -coronaphene series: Synthesis of di- [benzo [ c ] phenanthrene-3,10-dimethylene] . In: Helvetica Chimica Acta . 49, No. 7, 1966, p. 2123. doi : 10.1002 / hlca.660490717 .
Heinz A. Staab, François Diederich: Cycloarenes, a New Class of Aromatic Compounds, I. Synthesis of Kekulene . In: Chemical Reports . 116, No. 10, 1983, p. 3487. doi : 10.1002 / cber.19831161021 .
Claus Krieger, Francois Diederich, Dieter Schweitzer, Heinz A. Staab: Molecular Structure and Spectroscopic Properties of Kekulene . In: Angewandte Chemie International Edition in English . 18, No. 9, 1979, p. 699. doi : 10.1002 / anie.197906991 .
Junichi Aihara: Is superaromaticity a fact or an artifact? The cookie problem . In: Journal of the American Chemical Society . 114, No. 3, 1992, p. 865. doi : 10.1021 / ja00029a009 .
François Diederich, Heinz A. Staab: Benzenoidversus Annulenoid Aromaticity: Synthesis and Properties of Kekulene . In: Angewandte Chemie International Edition in English . 17, No. 5, 1978, p. 372. doi : 10.1002 / anie.197803721 .
Haijun Jiao, Paul von Ragué Schleyer: Is Kekulene Really Superaromatic? . In: Angewandte Chemie International Edition in English . 35, No. 20, 1996, p. 2383. doi : 10.1002 / anie.199623831 .
D. Schweitzer, KH Hausser, H. Vogler, F. Diederich, HA Staab: Electronic properties of kekulene . In: Molecular Physics . 46, No. 5, 1982, p. 1141. doi : 10.1080 / 00268978200101861 .
Jerzy Cioslowski, Peter B. O'Connor, Eugene D. Fleischmann: Is superbenzene superaromatic? . In: Journal of the American Chemical Society . 113, No. 4, 1991, p. 1086. doi : 10.1021 / ja00004a005 .
Heinz A. Staab, FrançOis Diederich, Claus Krieger, Dieter Schweitzer: Cycloarenes, a New Class of Aromatic Compounds, II. Molecular Structure and Spectroscopic Properties of Kekulene . In: Chemical Reports . 116, No. 10, 1983, p. 3504. doi : 10.1002 / cber.19831161022 .
Zhongxiang Zhou: Are kekulene, coronene, and corannulene tetraanion superaromatic? Theoretical examination using hardness indices . In: Journal of Physical Organic Chemistry . 8, No. 2, 1995, p. 103. doi : 10.1002 / poc.610080209 .

Notes and individual references

↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
^ Heinz A. Staab, François Diederich: Cycloarenes, a New Class of Aromatic Compounds, I. Synthesis of Kekulene . In: Chemical Reports . 116, No. 10, 1983, p. 3487. doi : 10.1002 / cber.19831161021 .
^ Claus Krieger, Francois Diederich, Dieter Schweitzer, Heinz A. Staab: Molecular Structure and Spectroscopic Properties of Kekulene . In: Angewandte Chemie International Edition in English . 18, No. 9, 1979, p. 699. doi : 10.1002 / anie.197906991 .
↑ Iago Pozo, Zsolt Majzik, Niko Pavliček, Manuel Melle-Franco, Enrique Guitián, Diego Peña, Leo Gross, Dolores Pérez: Revisiting Kekulene: Synthesis and Single-Molecule Imaging . In: Journal of the American Chemical Society . 141, No. 39, September 17, 2019, pp. 15488-15493. doi : 10.1021 / jacs.9b07926 .

[NV-1] This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.

[2] Heinz A. Staab, François Diederich: Cycloarenes, a New Class of Aromatic Compounds, I. Synthesis of Kekulene . In: Chemical Reports . 116, No. 10, 1983, p. 3487. doi : 10.1002 / cber.19831161021 .

[3] Claus Krieger, Francois Diederich, Dieter Schweitzer, Heinz A. Staab: Molecular Structure and Spectroscopic Properties of Kekulene . In: Angewandte Chemie International Edition in English . 18, No. 9, 1979, p. 699. doi : 10.1002 / anie.197906991 .

[4] Iago Pozo, Zsolt Majzik, Niko Pavliček, Manuel Melle-Franco, Enrique Guitián, Diego Peña, Leo Gross, Dolores Pérez: Revisiting Kekulene: Synthesis and Single-Molecule Imaging . In: Journal of the American Chemical Society . 141, No. 39, September 17, 2019, pp. 15488-15493. doi : 10.1021 / jacs.9b07926 .