Premium
Carbo ‐Benzene's Aromaticity, Before and Beyond: A Tribute to N ozoe
Author(s) -
Cocq Kévin,
Maraval Valérie,
SaffonMerceron Nathalie,
Chauvin Remi
Publication year - 2015
Publication title -
the chemical record
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.61
H-Index - 78
eISSN - 1528-0691
pISSN - 1527-8999
DOI - 10.1002/tcr.201402091
Subject(s) - adduct , benzene , chemistry , aromaticity , ring (chemistry) , computational chemistry , crystallography , organic chemistry , molecule
Beyond rigorous inspection of the literature, selected comments and drawings from the N ozoe Autograph Books show how concepts and targets of the chemistry of today already existed 40 years ago. This is illustrated for the chemistry of carbo ‐mers, which was actually unknowingly inspired by chemists of the golden age. After a personal travel through time and pages by the last author of this essay, who meets autographs by people who have been important in his career, in particular on the occasions of N ozoe's visits to F rance or past ISNA events, unpublished results in non‐benzenoid chemistry are dedicated to N ozoe's memory. Experimental advances are first disclosed on the comparative chemistry of the three ortho , meta and para isomers of tetraphenyl‐ carbo ‐benzene C 18 H 2 Ph 4 , the known ortho isomer serving as a reference. The two CH vertices of these chromophores make their [6]pericyclyne precursors quite sensitive and their yields and purifications challenging to optimize. The meta isomer was, however, isolated in 18% yield, and described by NMR and UV –vis absorption spectroscopy and crystallography. The para isomer was characterized both in pure form and in a 1:1 mixture with a single isomer of its HCl adduct, including by X ‐ray diffraction analysis of a co‐crystal showing that the interior of the C 18 ring of the HCl adduct is filled by the Cl atom. Theoretical advances are then offered regarding the “aromatic character” of a triple bond, by showing that the topological acyclic reference of acetylene is the M öbius‐twisted cyclobutadiene. Acetylenoids are finally proposed as a novel class of non‐benzenoid aromatics.