Poly(amidoamine) Dendrimers:  A New Class of High Capacity Chelating Agents for Cu(II) Ions

Abstract

This communication describes preliminary results of an experimental investigation of the binding of Cu(II) ions to poly-(amidoamine) (PAMAM) dendrimers in aqueous solutions. Dendrimers are highly branched polymers with controlled composition and architecture consisting of three structural components: a core, interior branch cells, and terminal branch cells. PAMAM dendrimers possess functional nitrogen and amide groups arranged in regular "branched upon branched" patterns which are displayed in geometrically progressive numbers as a function of generation level. Terminal groups of PAMAM dendrimers may be any organic substituent such as primary amines, carboxylic groups, etc. In aqueous solutions, PAMAM dendrimers can serve as high capacity nanoscale containers for toxic metal ions such as Cu(II). Compared to traditional chelating agents (e.g., triethylene tetramine) and macrocyles (e.g., cyclams) with nitrogen donors, which can typically bind only one Cu-(II) ion per molecule, a generation eight (G8) PAMAM dendrimer can bind up 153 ( 20 Cu(II) ions per molecule. This clearly illustrates a distinct advantage of dendrimers over traditional chelating agents and macrocycles; that is the covalent attachment of nitrogen ligands to conformationally flexible PAMAM chains enclosed within a nanoscopic structure results in a substantial increase in binding capacity.

Hyperbranched polydendrons: a new controlled macromolecular architecture with self-assembly in water and organic solvents

“…1A) and dendrimers 4 ( Fig. 1B) has led to a variety of chemistries, rivalling those available for linear polymers including: polyimines/polyamines, 5 polyurethanes, 6,7 polyethers, 8 polyesters, 9 polycarbonates, 10 polyamides, 11,12 polyamidoamines, 13 and polycarbosilanes.…”

Structure–Function Relationship of PAMAM Dendrimers as Robust Oil Dispersants

“…Due to their unique physicochemical properties, there are a wide variety of current and potential applications of dendrimers ranging from environment to energy and biomedicine. For example, hydroxyl-terminated PAMAM dendrimers have been shown to remove contaminants such as humic acids 2 and metal ions 3,4 from drinking water or contaminated soils. Dendrimers can be used in light-harvesting applications for superior transduction efficiency in diodes and other photonic devices.…”

Magnetic Properties of Transition Metal-Dendrimer Nanocomposites

“…The concentrations of metal in the final matrices were determined by atomic absorption to be 0.10 wt% Fe, 0.38 wt% Ni, and 0.30 wt% Co. Specific details of the sample preparation have been reported elsewhere [9,14]. All samples gave optically clear matrices indicating particle sizes less than 50 nm.…”