Azo-functionalized dendrimers

Abstract

We report the synthesis of azo-functionalized Starburst polyamidoamine (PAMAM) dendrimers. The following three systems of azo-functionalized PAMAM dendrimers were prepared by different synthetic routes: (i) phenylazo derivatives; (ii) naphthalimide azo derivatives; and (iii) phthalimide azo derivatives. Model compounds in each system were synthesized for spectroscopic comparison. Confirmation of structure was achieved using a combination of NMR and IR spectroscopy to ascertain the functional sites (i.e., the azo and the cyclic imides), while mass spectrometry and UV–vis spectrophotometry were employed to ascertain the extent of functionalization. Substitution by the azo pendent groups increased the thermal stability of PAMAM dendrimers (TGA weight loss of the naphthalimide azo-functionalized PAMAM dendrimers up to 300 °C, ca. 5%).Key words: dendrimers, azo compounds, hydrazones, tautomerism, hydrogen bonding.