Solubility and Crystallizability: Facile Access to Functionalized π-Conjugated Compounds with Chlorendylimide Protecting Groups

• Published in: Chemistry : a European journal 2015-01, Vol.21 (4), p.1542-1553
• Main Authors: Gebers, Jan, Rolland, Damien, Marty, Roman, Suàrez, Stéphane, Cervini, Luca, Scopelliti, Rosario, Brauer, Jan Cornelius, Frauenrath, Holger
• Format: Article
• Language: English
• Subjects: Crystallization; Derivatives; Diamines; Dicarboxylic acids; Electronics; functional molecules; polymers; protecting groups; Protective coatings; Solubility; supramolecular chemistry; Synthesis; synthetic methods
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201403623

Functional π‐conjugated molecules are relevant for the preparation of new organic electronic materials with improved performance. However, their synthesis is often rendered difficult by their inherently low solubility, and the permanent attachment of solubilizing groups may change the properties of the material. Here, we introduced the chlorendylimidyl moiety as a new temporary protecting group for the straightforward large‐scale synthesis of protected quarter‐, sexi‐, octathiophene, and perylene bisimide diamine and dicarboxylic acid derivatives. The obtained chlorendylimides and chlorendylimidyl active esters were highly soluble in organic solvents, and optical spectroscopy confirmed the low tendency of the compounds to aggregate in solution. At the same time, they could be conveniently purified by recrystallization or precipitation. Single‐crystal X‐ray structures obtained for most compounds showed supramolecular motifs highlighting the role of the rigid, polychlorinated chlorendyl moieties in their crystallization. The obtained protected diamine and dicarboxylic acid derivatives were easily deprotected and converted into various amide‐substituted oligothiophenes and perylene bisimides that are of interest as new functional materials for organic electronic thin film or nanowire devices. Solubility and crystallizability: The use of chlorendylimides as protecting groups for carboxylic acid and amine functionalities significantly facilitates the synthesis of end‐substituted π‐conjugated compounds, including octathiophene and perylene bisimide derivatives, by providing high solubility and crystallizability at the same time. The obtained compounds can then be readily converted to functional π‐conjugated compounds (see figure).