Premium
Anthracene‐Fused Dibenzo[ def , mno ]chrysenes with a Helical Structure
Author(s) -
Wang Qing,
Lim Gabriel,
Gopalakrishna Tullimilli Y.,
Han Yi,
Chi Chunyan
Publication year - 2018
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.201800326
Subject(s) - chemistry , helicene , chrysene , anthracene , diradical , steric effects , adduct , photochemistry , ring (chemistry) , conjugated system , crystallography , stereochemistry , organic chemistry , molecule , polymer , physics , nuclear physics , singlet state , excited state
Scholl‐type oxidative cyclodehydrogenation reactions were conducted for an anthryl‐substituted dibenzo[ def , mno ]chrysene (DBC) precursor with the intention to prepare anthracene‐fused DBCs with extended conjugation. The compound ADBC‐1 with one cyclized ring and its two chloro‐ and oxy‐ derivatives ( ADBC‐Cl and ADBC‐O ) with good stability were successfully isolated and characterized. They showed largely red‐shifted absorption spectra and amphoteric redox behavior. XRD analysis revealed that they can be regarded as large polycyclic aromatic hydrocarbons (PAHs) containing [5]helicene substructures with large twist angles of 67.8°–73.7° owing to steric congestion. Further cyclization to form newer C−C bonds failed, which can be explained by an open‐shell diradical character and high HOMO energy levels of the products according to spin‐unrestricted DFT calculations.