Poly(amide amine) Dendrimers with Naphthyl Units as Fluorescent Chemosensor Materials for Metal Cations

Abstract

Poly(amide amine) dendrimers with naphthyl units (Nn, n = 4, 8, 16, 32, 64) were synthesized for application as fluorescent chemosensor materials for metal cations. The metal cation recognition of Nn was also investigated. When Al³⁺, Zn²⁺, Cd²⁺, Ni²⁺, Mg²⁺, Ca²⁺, Ba²⁺, Co²⁺, or Ag⁺ were added to an acetonitrile/dichloromethane (1:1 v/v) solution containing Nn, the absorption spectra remained unchanged. However, the shape and intensity of the fluorescence spectra of Nn changed upon the addition of any of the metal cations except Ag⁺. Increasing n values of the naphthyl units resulted in selectivity for the metal cations. Selectivity for Al³⁺ and Zn²⁺, in particular, was excellent for N16, N32, and N64 dendrimers.