Cooperative Two-Component Self-Assembly of Mono- and Ditopic Monomers

A N-methylated benzene-1,3,5-tricarboxamide (BTA) was synthesized, characterized, and introduced as a monotopic BTA monomer capable of interacting with the supramolecular polymer formed via the cooperative self-assembly of the analogous ditopic BTA monomers. Using optical spectroscopy and viscometry, in combination with mathematical modeling and DFT calculations, we were able to understand in detail the consequence of introducing a second monotopic component in the self-assembly of BTA monomers into long supramolecular polymers, taking explicitly the cooperative nature of the self-assembly process into account. To this end, a binary self-assembly model that includes both the monotopic and ditopic BTA monomer and that addresses the presence of both monomers and polymers (characteristic of a cooperative supramolecular polymer) was developed and successfully applied to model the viscometry data. The binary self-assembly model presented herein can be more generally applied to other cooperative supramolecular polymers to which a second component is added that can interact with the monomers and/or polymers and thus can contribute to a better understanding of more complex self-assembling systems.