The manipulation of anions is critical across many areas of the energy sector. Promising solutions are receptors that can bind and release anions, such as photofoldamers. To optimize the photofoldamer for switching requires a fundamental understanding of the forces behind the changes in the apparent binding affinities upon switching between photostates. To understand these forces we deconvoluted the apparent binding affinity into its individual components; organizational energy and intrinsic binding affinity. Using a novel bi-stable arylazopyrazole foldamer, the energy contributions of both folding and binding were determined for each state of the photofoldamer. We discovered that the majority of the affinity swing in these photofoldamers was driven by changes in the organizational energy between the photostates, with a very minor contribution from changes in the intrinsic binding affinity towards anions. This work shows that the current affinity swings in aryl-triazole photofoldamers are limited by changes in the organizational energies. The intrinsic binding affinity amounts to a large untouched energy reserve, which if controllable, could be used to reach larger affinity swings than are currently accessible.

Controlling chloride affinity swings of photofoldamers with arylazopyrazoles

2019 Fall National Meeting

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