Condensed Derivatives of Thiadiazoloquinoxaline as Strong Acceptors

Abstract

Three novel thiadiazoloquinoxaline (TQ) derivatives, <b>TIPS-APhTQ</b>, <b>TIPS-PhTQ</b>, and <b>TIPS-BDTTQ</b>, were synthesized by introducing two triisopropylsilylethynyl groups and alternating the aromatic ring units in the condensed moiety of TQ. The synthetic route is very efficient, providing high yields. Cyclic voltammetry suggests high electron affinity values of −3.82, −3.95, and −3.99 eV for <b>TIPS-APhTQ</b>, <b>TIPS-PhTQ</b>, and <b>TIPS-BDTTQ</b>, respectively. Single-crystal X-ray diffraction reveals that three molecules form corresponding dimers by intermolecular S–N interaction and have very similar two-dimensional π-stacking. The π-stacking distances between them are as close as 3.34–3.46 Å