A Visible–Near-Infrared Light-Responsive Host–Guest Pair with Nanomolar Affinity in Water

Abstract: The discovery of stimuli-responsive high affinity

host–guest pairs with potential applications under biologically

relevant conditions is a challenging goal. This work

reports a high-affinity 1:1 complex formed between cucurbit[

8]uril and a water-soluble photochromic diarylethene

derivative. It was found that, by confining the open

isomer within the cavity of the receptor, a redshift in the

absorption spectrum and an enhancement of the photocyclization

quantum yield from F=0.04 to F=0.32 were

induced. This improvement in the photochemical performance

enables quantitative photocyclization with visible

light that, together with the near-infrared light-induced

ring-opening reaction and the 100-fold selectivity

for the closed isomer, confirms this as an outstanding

light-responsive affinity pair.