Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

The fluorescence quenching of 2-aminodiphenylamine (2ADPA), 4-aminodiphenylamine (4ADPA) and 4,4'-diaminodiphenylamine (DADPA) with tetrachloromethane, chloroform and dichloromethane have been studied in hexane, dioxane, acetonitrile and methanol as solvents. The quenching rate constants for the process have also been obtained by measuring the lifetimes of the fluorophores. The quenching was found to be dynamic in all cases. For 2ADPA and 4ADPA, the quenching rate constants of CCl₄ and CHCl₃ depend on the viscosity, whereas in the case of CH₂Cl₂, k_q depends on polarity. The quenching rate constants for DADPA with CCl₄ are viscosity-dependent but the quenching with CHCl₃ and CH₂Cl₂ depends on the polarity of the solvents. From the results, the quenching mechanism is explained by the formation of a non-emissive complex involving a charge-transfer interaction between the electronically excited fluorophores and ground-state chloromethanes.

Keywords: Fluorescence quenching; Dynamic quenching; Aminodiphenylamines; Non-emissive exciplex; Chloromethanes; Quenchers; Fluorescence spectroscopy; Solvent effects.

References: 20 live references.