Singlet Oxygen Responsive Molecular Receptor to Modulate Atropisomerism and Cation Binding

Abstract

In switchable molecular recognition, 1O2 stimulus responsive receptors offer a unique structural change that is rarely exploited. The employed [4+2] reaction between 1O2 and anthracene derivatives is quantitative, reversible and easily implemented. To evaluate the full potential of this new stimulus, a non‐macrocyclic anthracene‐based host was designed for the modular binding of cations. The structural investigation showed that 1O2 controlled the atropisomerism in an on/off fashion within the pair of hosts. The binding studies revealed higher association constants for the endoperoxide receptor compared to the parent anthracene, due to a more favoured preorganization of the recognition site. The fatigue of the 1O2 switchable hosts and their complexes was monitored over five cycles of cycloaddition/cycloreversion.