On the Stability of Metastable Monomers to Bias the Supramolecular Polymerization of Naphthalendiimides

Abstract Herein, we report the synthesis of the naphthalendiimides (NDIs) 1 – 3 endowed with peripheral 3,4,5‐trialkoxybenzamide units and a variable number of 1,2,3‐triazole rings. Both the benzamide units and the triazole rings are able to form six‐ or seven‐membered intramolecularly H‐bonded pseudocycles that behave as metastable monomeric units. Whilst freshly prepared solutions of 1 – 3 afford H‐type aggregates, the presence or lack of the 1,2,3‐triazole rings strongly conditions the kinetics and stability of the resulting aggregated species. These structural features result in highly stable metastable monomeric species M * for the symmetric 2 that can be trapped for long periods of time when the sample is subject to a heating/cooling cycle. Contrary to NDI 2 , the M * species formed by 1 and 3 evolve to the final supramolecular polymers in shorter times. A detailed experimental and theoretical study display the different non‐covalent supramolecular forces operating in the stabilization of such M * species. In all cases, but especially in those NDIs endowed with the triazoles rings (NDIs 2 and 3 ), a number of conformers for the metastable monomeric units can be modelled. The high stability of such monomeric species justifies the delay in the formation of the H‐type aggregates.