Electrochemistry, Spectroscopy, and Electrogenerated Chemiluminescence of Silole-Based Chromophores

We studied the electrochemical and spectroscopic properties of a series of extended silole-based chromophores to understand the effect of structure on behavior. By changing the substituents attached
to the chromophore, we observed large variations in luminescence quantum efficiency (ca. 0−0.6), λmax
for absorbance and photoluminescence (PL), and radical ion stability. The differences are related to the
motion in the 2,5-substituents and the steric protection of both the chromophore and the reactive parts of
the substituents. For several compounds the electrogenerated chemiluminescence (ECL) spectrum was
also compared to the photoluminescence spectrum. In all cases, the ECL λmax and the PL λmax were about
the same.