Synthesis of novel donor–acceptor twins

Abstract

Donor acceptor dimers 1a–f were prepared in four steps by coupling 1-(bromohexyloxy)-9,10-anthraquinone 5c to 2-hydroxy-3,6,7,10,11-pentakis(alkyloxy)triphenylenes 2a–f. Whereas differential scanning calorimetry and optical polarizing microscopy of those derivatives 1a–d with short alkyl chains revealed only crystal to soft plastic crystal transitions followed by isotropic melting, 1e,f with long alkyl chains possess a mesophase. Weak intramolecular charge-transfer interactions in solution were deduced from NMR and UV spectra.