Study on the mechanistic classes of fluorescence quenching of tryptanthrin-malononitrile adduct by aniline

[Display omitted] •The fluorescence quenching mechanism of 2-chloro-tryptanthrin-malononitrile adduct 2CTMA was investigated in detail.•Sphere of action static quenching model and finite sink approximation models were used for the study.•It was seen that the quenching involved both static and dynamic mechanisms without involving ground state complex formation.•As the value of KSV increases as the dielectric constant of the solvent mixture increases, quenching by charge transfer mechanism is not probably operating. Mechanistic studies of the fluorescence quenching of 2-(2-chloro-12-oxoindolo[2,1-b]quinazolin-6(12H)-ylidene)malononitrile (2CTMA) with aniline, using solvent mixtures of acetonitrile and 1,4-dioxane at room temperature, by steady-state and time-resolved methods is reported here. It was confirmed that, with the use of the sphere of action static quenching model and finite sink approximation model, that the bimolecular quenching reactions are due to the presence of both dynamic and static quenching processes.