Supramolecular Chirality Using Both Cooperative and Isodesmic Self‐Assembly: hierarchical growth through competition

Abstract A novel set of chiral self‐assembling discotic molecules has been prepared based on two previously studied self‐assembling C 3 ‐discotic systems, namely alkyl substituted benzene‐1,3,5‐tricarboxamides (alkyl‐BTAs) and 3,3′‐bis(acylamino)‐2,2′‐bipyridine substituted BTAs (BiPy‐BTAs). By replacing one of the three bipyridyl side chains by an alkyl chain we have prepared a hybrid system that shows properties of both parent compounds. Due to the different packing parameters and mechanisms of self‐assembly of the parent BTAs, one might expect a lack of ordering in such a hybrid system. However, we observe columnar mesophases and unique self‐assembly behavior in solution. We propose that the solution self‐assembly passes through three stages. First, disordered aggregates are formed that evolve into ordered aggregates via an isodesmic process. Finally, these ordered aggregates rearrange in a cooperative fashion into a higher ordered structure. Through the interplay between π–π interactions and H‐bonding, the hybrid molecules combine the cooperative self‐assembly behavior of alkyl‐BTAs with the isodesmic behavior of BiPy‐BTA discotics. This work shows that merging two systems with seemingly incompatible requirements can lead to new and complex self‐assembly behavior.