Platform Synthesis for the Rapid Construction of V-Shaped and Cruciform Push–Pull Compounds

Abstract

We report the modular synthesis of cruciform push–pull compounds from V-shaped di- and trisubstituted thiophenes obtained from commercially available 2,3-dibromothiophene (DBT) via sequential couplings using the concept of “platform synthesis”. Orthogonal C2/C3 functionalization with EDOT-and naphthothiophene-based molecular modules yielded a library of 8 V-shaped, sterically hindered π-conjugated derivatives. Coupling in C5 with electron-deficient benzothiadiazole units, to complete the “platform” synthetic sequence, afforded two different “cruciform-like” push–pull luminophores emitting in the deep red region of the visible spectrum. Photophysical and electrochemical studies, supported by calculations, revealed that the substitution pattern on DBT is crucial in tuning both emission efficiency and the bathochromic shifts, inducing aggregation-induced enhanced emission (AIEE) in one derivative. This work highlights the versatility of platform synthesis in the realization of relevant materials for optoelectronic applications.