Making a difference on excited-state chemistry by controlling free space within a nanocapsule: photochemistry of 1-(4-alkylphenyl)-3-phenylpropan-2-ones.

The free space within a reaction cavity plays a determining role during the excited-state reaction of 1-(4-alkylphenyl)-3-phenylpropan-2-ones included within a capsule formed by two molecules of a deep cavity cavitand. By controlling the free space within the reaction cavity through remote alkyl substitution on the reactant ketone it is possible to control the yield of the rearrangement product shown above.