Controlled Positioning of Activated Ester Moieties on Well‐Defined Linear Polymer Chains

Abstract

The successful sequence-controlled installation of an activated ester using a newly designed monomer pentafluorophenyl 4-maleimidobenzoate is demonstrated. Pentafluorophenyl 4-maleimidobenzoate is kinetically installed at different stages of a nitroxide-mediated polymerization, namely, near the α-chain end and in the middle of a PS chain. In addition, successful installation of apolar and polar functional groups is achieved via post-polymerization functionalization, which demonstrated the versatility of the synthesis of a universal precursor for locally functionalized polymers.

Sequence-controlled polymers via reversible-deactivation radical polymerization

“…This means that the minor monomer selectively propagates over the primarily existing monomer even though there is a big difference in the injected amounts of the comonomers. Lutz and co-workers [36][37][38][39][40][41][42][43][44] noticed the crossover propagation feature of the alternating copolymerization for achieving local functionalization of a polymer chain using RDRP (Figure 6a). In this approach, styrene or the derivative is polymerized with RDRP (ATRP or NMP), and a slight excess of an MI derivative is added to the growing chains during the RDRP for pinpoint insertion.…”

Functional Polymers with Controlled Microstructure Based on Styrene and N ‐Substituted Maleimides

“…This system was expected to be viable because the consumption of N-substituted maleimide when copolymerized with styrene is extremely fast compared to styrene and will be incorporated locally on the growing polymer chain. This strategy was developed first for the ATRP system [77,78] because the homopolymerization of styrene [79][80][81] and copolymerization of styrene and maleimides [59,61,63] are largely reported in the literature, but it was then extended to the NMP system [82,83].…”

“…The N-substituted maleimides evaluated with this technique in our laboratory are shown in Figure 7.1 [78,83,84]. Since a fast and local incorporation of the maleimide is required to promote the precise positioning of this monomer on the polystyrene backbone, high cross-propagation between these monomer pairs is needed.…”

“…When the copolymerization was performed in N,N-dimethylformamide, the polymerization was homogeneous, but this functional maleimide interfered with the ATRP catalyst, inhibiting the polymerization. However, the biotin could be introduced on the polymer backbone by post-polymerization modification [83].…”

“…In a recent study, a maleimide functionalized with pentafluorophenyl ester, in particular pentafluorophenyl 4-maleimidobenzoate (21), was synthesized and copolymerized with styrene under NMP in the presence of BlocBuilder MA [83]. The active ester moiety was kinetically installed at the early stage of polymerization (i.e., near the α-chain end) and in the middle of highly defined polystyrene chains.…”