Reactivity-gated photochromism of 1,2-dithienylethenes for potential use in dosimetry applications

A novel molecular switching system based on reactivity-gated photochromism operates because a butadiene undergoes a [4 + 2] cycloaddition reaction with a dienophile to produce the photoresponsive 1,2-dithienylethene backbone. The reversible change in color when samples are irradiated with appropriate wavelengths of light occurs only after the Diels-Alder cycloaddition reaction takes place.