Phenylimino Indolinone: a Green Light Responsive T-Type Photoswitch Exhibiting Negative Photochromism.

Imines are photoaddressable motifs useful in the development of new generations of molecular switches, but their operation with low energy photons and control over isomer stability remain challenging. Based on a computational design, we developed Phenylimino Indolinone (PIO), a green-light addressable T-type photoswitch, showing negative photochromism. The isomerization behavior of this photoactuator of the Iminothioindoxyl (ITI) class was studied using time-resolved spectroscopies on time scales from femtoseconds to steady-state, and by quantum chemical analyses. The understanding of the isomerization properties and substituent effects governing these photoswitches opens new avenues for the development of novel T-type, visible-light addressable photoactuators based on C=N bonds.