Photophysical and photoprototropic characteristics of phenothiazine in aqueous and β-cyclodextrin media

The photophysical and photoprototropic characteristics of phenothiazine (PTZ) in aqueous and beta-cyclodextrin (beta-CD) media have been investigated using absorption, steady state and time resolved fluorescence measurements. The absorbance and fluorescence intensities of the neutral and mono-cationic forms of PTZ are enhanced by the addition of beta-cyclodextrin and it is due to the formation of 1:1 inclusion complex. The formation of complex is confirmed by the decay analysis and Job's continuous variation method in the liquid state while FT-IR spectral study and SEM image analysis in the solid state. The peak and pK(a)* values of PTZ in aqueous media are higher than in beta-CD medium, which reveals that the > NH group of VIZ lies in the beta-CD cavity. (C) 2015 Elsevier B.V. All rights reserved.