Compartmentalization of Single Polymer Chains by Stepwise Intramolecular Cross-Linking of Sequence-Controlled Macromolecules

Abstract

We report the intramolecular double compaction of sequence-controlled linear macromolecules into "structured" random coils. These compartmentalized single-chain objects were prepared by performing successive cross-linking reactions in an orthogonal fashion. The foldable precursors were synthesized by sequence-controlled copolymerization of styrene with N-substituted maleimides (MIs), namely pentafluorophenyl 4-maleimidobenzoate (1) and TIPS-protected N-propargyl maleimide (2). These two functional MIs allow intramolecular cross-linking. The activated ester pentafluorophenyl moieties of 1 were reacted with ethylenediamine, whereas the deprotected alkyne functions of 2 were self-reacted by Eglinton coupling. The compaction of model copolymers containing only one cross-linkable zone (i.e., either 1 or 2) was first studied. (1)H NMR and SEC analysis indicated that these structures could be efficiently compacted into single-chain objects. Thus, more complex copolymers containing two individually addressable cross-linking zones were prepared and sequentially compacted. Detailed characterization of the folding process indicated that double-compaction occurred and that the formed single-chain particles contain distinct cross-linked subdomains.

Synthesis of Non-Natural Sequence-Encoded Polymers Using Phosphoramidite Chemistry

“…1,2 Indeed, the precise adjustment of monomer units in polymer chains opens up interesting perspectives for controlling molecular, supramolecular and macroscopic properties of polymer materials. [3][4][5][6][7][8][9][10] Thus, many new concepts for monomer sequence-regulation have been introduced during the last few years. [11][12][13] For example, strategies for controlling comonomer sequences in classical polymerization approaches such as chain-growth [14][15][16][17][18][19] and stepgrowth 20 polymerizations have been described.…”

Stepwise Unfolding of Single‐Chain Nanoparticles by Chemically Triggered Gates

“…[1][2][3] Proteins fold dynamically into more complex structures,s uch as a-helices and b-sheets.I ntramolecular hydrogen bonds,a romatic stacking, and hydrophobic interactions typically stabilize the formed architectures. [13][14][15][16] Theresulting folded structures are mostly stabilized by noncovalent interactions, [5] such as hydrogen bonds, [17][18][19] p-p stacking, [20] host-guest interactions, [21,22] and metal complexation, [23,24] yet studies to trigger the defined unfolding of dynamic SCNPs are scarce. [6,7] Thef ield of single-chain folding is ag rowing area of polymer science and takes inspiration from natures folding processes.…”

Self-assembly and disassembly of stimuli responsive tadpole-like single chain nanoparticles using a switchable hydrophilic/hydrophobic boronic acid cross-linker

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