Perfluorophenyl Azides: Photo, Staudinger, and Multicomponent Postpolymerization Reactions on Homopolymers and PISA-Made Nanoparticles

Abstract

A novel monomer, 4-azido-2,3,5,6-tetrafluorobenzyl methacrylate (ABMA), enabled the selective and efficient postpolymerization modification of reversible addition–fragmentation chain transfer­(RAFT)-made homopolymers and diblock copolymer nanoparticles prepared through polymerization-induced self-assembly (PISA). Poly­(ABMA) homopolymers were modified postpolymerization in (near-)­quantitative conversions with phosphines to give stable iminophosphoranes and in a multicomponent reaction with phenylacetaldehyde and morpholine, piperidine, or the cross-linker N,N′-dimethylethylene diamine to give the corresponding amidine derivatives in one step. Product polymers were characterized by nuclear magnetic resonance and Fourier-transform infrared spectroscopy, size-exclusion chromatography, and differential scanning calorimetry. Unlike its monomer, poly­(ABMA) was insoluble in ethanol and enabled the preparation of well-defined spherical, worm-shaped, and vesicular nanoparticles with azide-functional cores through RAFT dispersion polymerization with concurrent PISA. The worm-shaped particles formed physical gels that underwent a thermally reversible degelation. Multicomponent modification of spherical nanoparticles with phenyl acetaldehyde and morpholine or piperidine led to (near-)­quantitative core modification and for morpholine, a significant increase in its sphere diameter. UV irradiation of nanoparticles led to cross-linking through the formation of reactive nitrene intermediates, which prevented the disassembly of nanoparticles in nonselective solvents, representing a simple and reagent-free cross-linking strategy and expanding the scope of azide-based polymer chemistry.

Advances in Functionalized Photosensitive Polymeric Nanocarriers

“…Multicomponent modification of NPs with phenylacetaldehyde, morpholine, piperidine, or the N,N -dimethylethylene cross-linker led to the corresponding amidine derivatives (core modification) in one step. UV irradiation of NPs led to their stable cross-linking through the formation of reactive nitrene intermediates, avoided disassembly in nonselective solvents, resulting in a simple and reagent-free cross-linking strategy azide-polymer chemistry [120].…”

Azide- and Fluorine-Containing Polystyrenes as Potential ″Phosphine Sponges″ Based upon Staudinger Reactions: Application to the Phase Transfer Activation of Grubbs’ Catalyst

“…The only examples of which we are aware are shown in Figure 13. 36 These were undertaken as part of an effort to explore postpolymer modifications of methacrylate esters 18. Interestingly, studies of the ″inverse reactions″�that is, those of non-polymeric azides and polymer bound phosphines�have been described.…”

“…While this work was in the final stages, another example of a Staudinger reaction and a polymer with an azide in the repeat unit was reported (discussion section). 36 ■…”

“…Indeed, a variety of polymers with pendant azide groups in the repeat unit have been prepared. − For example, the copolymer of 2,3,4,5,6-pentafluorostyrene and 4-azido-2,3,5,6-tetrafluorostyrene has been reported. ,, Surprisingly, when this project was initiated, none of these had ever been used for Staudinger reactions, although the ready reactivity of polymer-based azide groups had been established in click [3 + 2] cycloadditions with alkynes. − …”

Playing construction with the monomer toy box for the synthesis of multi‐stimuli responsive copolymers by reversible deactivation radical polymerization protocols

“…In a recent work, the azide group was present directly in the p ‐position of 1,2,4,5‐tetrafluorobenzyl methacrylate for direct RAFT polymerization of this novel monomer. The authors then explored the post‐polymerization chemistry (Scheme 6) that can be performed on both the free polymers and their nanoaggregates obtained in polymerization‐induced self‐assembly (PISA) conditions 127 . Although the subject of MSR materials is not tackled in this work, such a versatile system can easily be expected to have a significant impact on this field of research.…”