Trifluoroacetyl-chlorin as a new chemosensor for alcohol/amine detection

Chlorophyll derivative possessing a trifluoroacetyl group at the 3-position was synthesized as a new chemosensor for alcohols and amines. Intense Q_y peak of the trifluoroacetyl-chlorin (701 nm in CHCl₃) showed blue shifts to 667 nm in MeOH and 665 nm in n-BuNH₂ due to the formation of the corresponding hemiacetal and hemiaminal with visible color changes. Thermodynamic parameters for the complexation between trifluoroacetyl-chlorin and n-BuNH₂ in CDCl₃ were determined to be ΔH = −48 kJ mol⁻¹ and ΔS = −147 J K⁻¹ mol⁻¹. Ratiometric fluorescence sensing of n-BuNH₂ in THF was also demonstrated.