A Comparative Study on the Photophysical and Photochemical Properties of Dyes in the Presence of Low Generation Amino-terminated PAMAM Dendrimers

GRASSANO, MICAELA E.; ALTAMIRANO, MARCELA S.; MILITELLO, M. PAULA; ARBELOA, ERNESTO M.; PREVITALI, CARLOS M.; BERTOLOTTI, SONIA G.

PHOTOCHEMISTRY AND PHOTOBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2018

0031-8655

The photophysical and photochemical properties of the xanthene dyes mercurochrome (MCr) and eosin‐Y (Eos); and the phenazine dye safranine‐O (SF) are evaluated in the presence of amino‐terminated polyamidoamine (PAMAM) dendrimers of low generations. The dendrimers produce a red shift in the UV‐vis absorption spectra of the dyes, which increases with concentration and the size of the PAMAM molecule. The Stern‐Volmer plots of fluorescence quenching for xanthenic dyes present a downward curvature. It is ascribed to a static mechanism involving a dye‐dendrimer binding. A non‐linear fitting of the SV plots allows the calculation of the binding constants. For SF the fluorescence is only slightly quenched by PAMAMs and the SV plots are linear. The binding constants are in the order Kbind (SF)