Study of the interaction of Eosin Y-PAMAM interactions in alkaline aqueous solution

ERNESTO M. ARBELOA; CARLOS M. PREVITALI; SONIA G. BERTOLOTTI

JOURNAL OF LUMINESCENCE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015

0022-2313

The interaction between the xanthene dye Eosin-Y (Eos) and amine-terminated PAMAM dendrimers of low generations (G0-G3) were studied in alkaline water solution. The effect of concentration and generation of the dendrimer on the photophysics of Eos was evaluated by means of absorption and fgluorescence spectroscopies. The observed spectral changes were ascribed to the association dye/dendrimer. From the data, the Eos/PAMAM binding constants (Kbind) were determined, which strongly increased with the size of the dendrimer. Stationary fluorescence anisotropy and time resolved single photon counting were used to characterize the associuation process. The restriction in the rotational diffusion of the Eos invreased as a function of the concentration and generation of PAMAM, as determined by anisotropy measurements. Biexponential fluorescence decays were obtained in the presence og G3, and the respective lifetimes were ascribed to free and bound Eos species. These results correlate con Kbind values and suggest the formation of host/guest system with larger dendrimers. Therefore, this environmentally-friendly dye/dendrimer system would be appropiate for potential applications in fields such as drugs delivery and photopolymerization.