Synthesis of Dendronized Polymers via a “m+n” Grafting-onto Strategy with Reaction-Enhanced Reactivity of Intermediates (RERI) Mechanism

Dendronized polymers (DenPols) with tunable shape and surface property have been recognized as a type of promising unimolecular nanomaterials. However, it still has lacked a rapid and efficient approach to the facile synthesis of DenPols with high-generation and well-defined structures. Herein, we report a “m+n” grafting-onto strategy combined with the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction with reaction-enhanced reactivity of intermediates (RERI) mechanism for synthesizing DenPols G_m+n by attaching n-generation dendrons (G_n) onto the m-generation DenPols G_m. In this “m+n” grafting-onto strategy, the DenPols G_m (m = 1, 2) bearing 1,3-triazido branches on the repeating unit were capable of RERI effect that guaranteed the CuAAC reaction in an extremely efficient way with ultrafast kinetics to synthesize third-, fourth- and fifth-generation DenPols (G₁₊₂, G₁₊₃, G₁₊₄, G₂₊₂, and G₂₊₃) with near quantitative grafting density and narrow distribution. Moreover, these resultant DenPols G_m+n had more terminal groups per repeating unit due to the three branches of 1,3-triazido structure, exhibiting valuable potential opportunities for molecular surface engineering. The development of this “m+n” grafting-onto strategy with RERI mechanism not only presents a new avenue for ultrafast preparing DenPols but also holds great promise for preparing unimolecular materials with more functional terminal groups.