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), lambdamax 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 lambdamax and the PL lambdamax were about the same.