Toward New Materials for Organic Electroluminescent Devices: Synthesis, Structures, and Properties of a Series of 2,5-Diaryl-3,4-diphenylsiloles

Abstract

A series of 2,5‐diaryl‐3,4‐diphenylsiloles, with various mono‐substituted phenyl groups, extended π‐conjugated groups, and heteroaryl groups as aryl groups at the 2,5‐positions, has been prepared by a one‐pot synthesis from bis(phenylethynyl)silanes based on the intramolecular reductive cyclization followed by the palladium‐catalyzed cross‐coupling with aryl halides. Crystal structures and chemical reactivities toward the alkaline desilylation reactions have been studied on the 2,5‐bis(p‐mono‐substituted phenyl)silole derivatives to elucidate the effects of the p‐substituents. The UV‐visible absorption and fluorescence spectra, and cyclic voltammetry of the 2,5‐diarylsiloles have been systematically evaluated. Their photophysical properties as well as their electronic structures significantly depend on the nature of the 2,5‐aryl groups.