Fluorescent properties and resonance energy transfer of 3,4-bis(2,4-difluorophenyl)-maleimide

A fluorescent compound 3,4-bis(2,4-difluorophenyl)-maleimide 1 from the 3,4-diaryl-substituted maleimides was synthesized and determined to have a Stokes shift of 140 nm (λ_abs 341 nm, λ_em 481 nm), a high fluorescent quantum yield (Φ_fl 0.61) and an extinction coefficient ε₍₃₄₀₎ of 48 400 M⁻¹ cm⁻¹ in dichloromethane. For the first time we demonstrated the successful implementation of a 3,4-diaryl-substituted maleimide molecule as a donor component in FRET experiments.