Proton‐Gated Photoisomerization of Amino‐Substituted Dibenzofulvene Rotors

Derivatives of 9-(2,2,2-triphenylethylidene)-fluorene (TEF) undergo E/Z photoisomerization and are candidates for light-powered molecular actuators and switches. The 2-substituted derivatives bearing an amino group (ATEF) or a dimethylamino group (DTEF) are weakly photoactive in the absence of acids, but protonation increases photoisomerization quantum yields by factors of 30–60. Such compounds may be useful for incorporation into pH-switchable photoactive devices.