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Quinoxalinophenanthrophenazines (QPPs) and Hexabenzoovalenes (HBOs) – Proving the Solubility Enhancement by Triptycene End‐Capping
Author(s) -
Kohl Bernd,
Baumgärtner Kevin,
Rominger Frank,
Mastalerz Michael
Publication year - 2019
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201900819
Subject(s) - solubility , triptycene , chemistry , alkyl , intermolecular force , stacking , hildebrand solubility parameter , organic chemistry , molecule
Unsubstituted larger fused polyaromatic compounds are of very low solubility because of strong intermolecular stacking forces of adjacent π‐planes. To overcome this problem, long and sometimes branched alkyl‐ or alkoxychains are widely used as peripheral moieties to increase the solubility. The larger the dimensions of the π‐planes are, the longer the attached alkyl chains need to be to sufficiently increase solubility. Unfortunately, such compounds usually tend to form liquid crystals rather than single crystals that could, for example, provide detailed structural information. Recently we introduced the derivatization of larger aromatic compounds with triptycenylene end‐caps, which showed an increased solubility but also a good tendency to form large single crystals. However, the factor explaining the enhanced solubility has never been determined. Herein, we compare two series of extended π‐systems, namely the quinoxalinophenanthrophenazines (QPPs) and hexabenzoovalenes (HBO) to experimentally evaluate the impact of triptycene units on solubility.