A Photochemically Driven Molecular Machine

Abstract

The unthreading and rethreading of pseudorotaxane 1, which contains two p-phenylene spacers linking two bipyridinium units and a central 1, 5-naphthalenediyl unit, is reversible when an initially oxygen-free solution of 1 in water also containing 9-anthracenecarboxylic acid as a photosensitizes and triethanolamine as a “sacrificial” reluctant is irradiated and then aerated. The absorption and emission spectra of the solution provide conclusive evidence.