Collect. Czech. Chem. Commun. 2002, 67, 1154-1164

Fluorescence Quenching of Aminodiphenylamines with Chloromethanes

Nachiappan Radha and Meenakshisundaram Swaminathan*

Department of Chemistry, Annamalai University, Annamalainagar - 608 002, Tamilnadu, India


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, kq 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.