Preparation of Poly[(ether)-(ether ether ketone)] Dendrimers by the Convergent Method

Abstract

New highly branched poly[(ether)-(ether ether ketone)] dendrimers were synthesized by the convergent approach using two building blocks, 3, 5-dihydroxybenzyl alcohol, 1, and 3, 5-dihydroxy-4′-(4-fluorobenzoyl)diphenylether, 2, alternatively. The reaction of p-fluorobenzonitrile and 1 gave 3, 5-di(4-cyanophenoxy)benzylalcohol (the first generation dendron, G1-OH). After G1-OH was converted to 3, 5-di(4-cyanophenoxy)benzylbromide (G1-Br), the resultant benzylic bromide functionality was allowed to react with 2 to yield the second-generation dendron (G2-F). The third-generation dendron (G3-OH) was obtained by the reaction of G2-F and 1, and the fourth-generation dendron (G4-F) was obtained by reaction of G3-Br derived from G3-OH, with 2. Finally, dendrimers, Den-(G2)3 and Den-(G4)3 were synthesized by reaction of G2-F and G4-F with trifunctional core, respectively. Analysis was made of these structurally unambiguous dendrons and dendrimers by gel permeation chromatography (GPC) and matrix-assisted laser desorption ionization time of flight (MALDI-TOF) mass spectroscopy. 1H and 13C NMR spectra were consistent with the structures of these dendrons and dendrimers.