Preparation of Multifunctional Regio‐ and Stereo‐Regular hb‐Polyamines via C(sp3)─H Activation‐Based Polyamination of Internal Alkynes

Abstract

AbstractHyperbranched polymers have been widely applied in various fields because of their good solubility, high reactive end groups, and low viscosity, etc. Therefore, it is of great importance to develop new strategies to build multifunctional hyperbranched polymers with novel architectures. In this work, a C(sp3)─H activation‐based polymerization of internal alkynes and bifunctional secondary amines is successfully established, and multifunctional hyperbranched polyamines (hb‐PAs) with 100% E‐isomers and high molecular weights (Mw up to 76 500) are prepared in good yields (up to 82%). The hb‐PAs containing tetraphenylethylene moiety show unique aggregation‐enhanced emission properties and can be used for explosive detection with a low limit of detection (9.14 × 10−8 m). Notably, the hb‐PAs display high refractive indices (up to 1.7607) that can be further modulated to 1.7825 by the coordination of its peripheral ethynyl group with metallic cobalt. Moreover, the hyperbranched structure endows the hb‐PAs with much better properties than their linear counterparts, such as higher photoluminescence quantum yields and refractive indices. In addition, the hb‐PAs can be modified by a C(sp3)─H activation reaction of internal alkynes and alcohols. This work not only prepares a series of functional nitrogen‐containing hyperbranched polymers but also promotes the application of C(sp3)─H activation in polymer chemistry.