Benzoxazine/Triphenylamine-Based Dendrimers Prepared through Facile One-Pot Mannich Condensations

A series of thermally polymerizable dendrimers of various generations, equipped with triphenylamine (TPA) and benzoxazine (BZ) groups, is synthesized through facile one-pot Mannich condensations of N-1, N-1-bis(4-aminophenyl) benzene-1,4-diamine (TPA-3NH(2), as the core group), 4-(bis(4-aminophenyl) amino) phenol (TPA-2NH(2)-OH, as the AB(2) branching group), and CH2O in 1,4-dioxane. The ratios of the integrated areas in the H-1 nuclear magnetic resonance spectra of these dendrimers are consistent with the theoretical numbers of protons, suggesting their successful syntheses. Bathochromic shifts of signals are evident in the UV-vis and photoluminescence spectra upon increasing the generation of the TPA-BZ dendrimers, consistent with an increase in the effective conjugation length. The TPA-BZ dendrimers are able to undergo thermal polymerization and display unique optical physical properties, resulting in thermoset TPA networks after thermal ring-opening polymerization.