Correlating Structures to Electrochemiluminescence Efficiencies of Silole Compounds in Coreactant Systems

Abstract To develop efficient electrochemiluminescence (ECL) of activated silole chromophores, the relative ECL efficiencies of eight thiophene‐containing compounds are firstly studied in a coreactant pathway. The experimental results show that the extended π‐conjugated systems and donor groups of the silole emitters affect both the radical stability and emission efficiencies. It is found that the 1,1‐di‐ tert ‐butyl‐2,5‐bis[(2,2′‐bithiophen)‐5‐yl]‐3,4‐diphenylsilole (2c) compound with benzoyl peroxide (BPO) as a coreactant exhibits the highest relative ECL efficiencies among the studied systems due to its structural properties. Moreover, the absolute ECL efficiency of the potential pulsing/ECL experiment in the coreactant pathway is 6‐fold larger than that in the potentiodynamic experiment due to the short time interval for the radical species to meet and react. This work provides a guidance for structural modification of silole compounds to tune ECL performance.