Structure and Photophysical Properties of Silane Bridged Tetraphenylethylene-Oligothiophene Derivatives

Abstract

A series of silane-bridged tetraphenylethene (TPE)-oligothiophene derivatives were synthesized. The silane substituents varied from methyl to phenyl groups, while the number of thiophene units in the oligothiophene segment was 1 to 3. The solid-state luminescence properties of the molecules were regulated by steric hindrance and electronic effects. Phenyl substituted silane-bridged bithiophene (BT)-TPE molecules exhibited up to 64.5% solid-state luminescence. Molecules containing 1 or 2 thiophene units exhibited fluorescence properties similar to TPE in both solid and liquid states, while the emission of molecules containing 3 thiophene units mainly came from terthiophene (TT) with luminescence efficiencies of 1.4% and 14% in liquid and aggregated states, respectively. The aggregate of phenyl substituted silane-bridged TT-TPE molecules exhibited potential for detecting nitro explosives and anti-counterfeiting applications.