Electronic substituent effects on hydrogen-bonding motifs modulate supramolecular polymerisation

Hydrogen-bond assembled supramolecular polymers receive enormous interest as stimuli responsive materials that can be obtained using small easy to purify organic molecules. A key feature that determines materials properties in dilute solution is the strength of interaction between supramolecular synthons. In this work we illustrate that electronic substituents which are conjugated to the hydrogen-bonding motif can have subtle but significant effects on the degree of supramolecular polymerisation. Using ureidopyrimidines which contain electron donating phenolate and benzoate ester linkages in direct electronic communication with the self-complementary hydrogen-bonding motif, diffusion ordered spectroscopy (DOSY) demonstrates predictable differences in the extent of supramolecular polymerisation.