Regiochemical effects for the mechanochemical activation of 9-π-extended anthracene-maleimide Diels–Alder adducts

Abstract

The attachment point of the polymer chain to a force-responsive molecular unit (mechanophore) is a decisive parameter determining bond scission rate and ultimately the mechanochemical reaction outcome. However, such regiochemical polymer substituent effects have not yet been investigated for 9-π-extended anthracene-maleimide Diels-Alder adducts. Here we combine three methods, namely ultrasonication, CoGEF computation, and flow activation, to understand the influence of the pulling point location on the mechanochemical reactivity of this mechanophore class. We find minor mechanochemical reactivity differences between the investigated constitutional mechanophore isomers. Concomitantly, our results highlight the capabilities and limitations of the employed experimental techniques for such delicate variances and raise the question whether these are relevant for mechanochemical applications in a material context.