Semi-Telechelic Polymers from Mechanochemical CDC Bond Activation

Unstrained CC bond activation is attained in homopolymers through mechanochemical bond scission followed by functionalization to yield mostly semi-telechelic polymer chains. Ball milling poly(ethylene oxide) (PEO) in the presence of 1-(bromoacetyl)pyrene (BAPy) yields the pyrene terminated PEO. Similarly, milling with 2,4 '-dibromoacetophenone followed by Suzuki coupling allows the introduction of various aryl end groups. PEOs with a molecular weight below 20 kDa show no functionalization, supporting a mechanochemical mechanism. The protocol is also tested with doxorubicin, yielding the drug-polymer conjugate. PEO halogenation is also demonstrated by milling PEO with iodine, N-bromosuccinimide, or N-iodosuccinimide, which can then be reacted with an amine substituted anthracene. Grinding additional carbon polymers with BAPy indicates that this functionalization method is general for different polymer chemistries. Mechanochemical CC bond activation is used to introduce different end groups to macromolecular chains, yielding mono-telechelic polymers. Ball milling poly(ethylene oxide) in the presence of adequate small molecules enabled the functionalization with fluorescent tags, halogens, or a bromo-aryl moiety, which undergoes further functionalization via Suzuki coupling. The protocol is demonstrated in several carbon-based polymer chemistries.image