Abstract A comprehensive characterization of the electronic spectral and photophysical properties of the leuco (reduced) form of several indigo derivatives, including indigo and Tyrian Purple, with di-, tetra-, and hexa-substitution, was obtained in solution. The characterization involves absorption, fluorescence, and triplet–triplet absorption spectra, together with quantitative measurements of quantum yields of fluorescence, ϕ F (0.46– ...
![disodium [2,2'-bi-1H-indole]-3,3'-diolate Structure](https://image.chemsrc.com/caspic/147/894-86-0.png)