Synthesis and characterization of poly(amido amine) dendrimer containing fluorene as a core chromophore

The synthetic strategy for the convergent synthesis of emissive poly(amido amine) (PAMAM) den-drimers having the core chromophore via the copper-catalyzed 1,3-dipolar cycloaddition reaction between alkyne and azide was described. 2,7-Diazido-9H-fluorene, designed and synthesized to serve as the core in dendrimer, was stitched with the propargyl-functionalized PAMAM dendrons by the click chemistry leading to the formation of fluorescent PAMAM dendrimers in high yields. The absorption and emission of the dendrimers were investigated. Their photophysical studies indicated that 2,7-diazido-9H-fluorene showed no fluorescence due to the quenching effect from the electron-rich alpha-nitrogen of the azido group but the dendrimers fluoresced due to the elimination of the quenching through the formation of the triazole ring.