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Four Generations of Water‐Soluble Dendrimers with 9 to 243 Benzoate Tethers: Synthesis and Dendritic Effects on Their Ion Pairing with Acetylcholine, Benzyltriethylammonium, and Dopamine in Water
Author(s) -
Boisselier Elodie,
Ornelas Cátia,
Pianet Isabelle,
Aranzaes Jaime Ruiz,
Astruc Didier
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200701607
Subject(s) - dendrimer , chemistry , carboxylate , pairing , monomer , ion , polymer chemistry , nuclear magnetic resonance spectroscopy , crystallography , proton nmr , stereochemistry , organic chemistry , polymer , physics , superconductivity , quantum mechanics
Abstract Water‐soluble benzoate‐terminated dendrimers of four generations (from G 0 with 9 branches to G 3 with 243 branches) were synthesized and fully characterized. They form water‐soluble assemblies by ion‐pairing interactions with three cations of medicinal interest (acetylcoline, benzyltriethylammonium, and dopamine), which were characterized and investigated by 1 H NMR spectroscopy, whereas such interactions do not provoke any significant shift of 1 H NMR signals with the monomeric benzoate anion. The calculated association constants confirm that the dendritic carboxylate termini reversibly form ion pairs and aggregates. Diffusion coefficients and hydrodynamic diameters of the dendrimers, as well as changes thereof on interaction with the cations, were evaluated by DOSY experiments. The lack of increase of dendrimer size on addition of the cations and the upfield shifts of the 1 H NMR signals of the cation indicate encapsulation within the hydrophobic dendrimer interiors together with probable backfolding of the benzoate termini.