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True tertiary architectures with defined local secondary structures are rare in synthetic systems. Adapting well‐developed synthetic building blocks and controlling their folding through diverse interactions can be a general approach toward this goal. In this contribution, the synthesis of 3D hierarchical assemblies with distinct secondary domains formed through the intramolecular folding of a block copolymer containing a coil‐like poly(styrene) (PS) block with a helical poly(isocyanide) block induced by phenyl‐pentafluorophenyl quadrupole interactions is reported. The PS block is prepared via atom‐transfer radical polymerization and end functionalized with a nickel complex that serves as a macroinitiator for the polymerization of chiral isocyanides bearing pentafluorophenyl pendants. The folding behavior of the coil‐helix block copolymers is investigated by dynamic light scattering, NMR spectroscopy, wide‐angle X‐ray scattering, and differential scanning calorimetry.

 

Helical poly(isocyanide)s are an important class of synthetic polymers possessing a static helical structure. Since their initial discovery, numerous examples of these helices have been fabricated. In this contribution, the synthesis of a chiral, azobenzene (azo)‐containing isocyanide monomer is reported. Upon polymerization with nickel(II) catalysts, a well‐defined circular dichroism (CD) trace is obtained, corresponding to the formation of a right‐handed polymeric helix. The helical polymer, dissolved in chloroform and irradiated with UV light (365 nm), undergoes acistotransisomerization of the azobenzene side‐chains. After the isomerization, a change in conformation of the helix occurs, as evidenced by CD spectroscopy. When the solution is irradiated with LED light, the polymer returns to a right‐handed helical conformation. To open up the possibility for chain‐end post‐polymerization modification of this light‐responsive system, an alkyne‐functionalized nickel(II) catalyst is also used in the polymerization of the azobenzene monomer, resulting in a stimuli‐responsive, terminal‐alkyne‐containing helical poly(isocyanide).

 

Novel antiviral nanotherapeutics, which may inactivate the virus and block it from entering host cells, represent an important challenge to face viral global health emergencies around the world. Using a combination of bioorthogonal copper-catalyzed 1,3-dipolar alkyne/azide cycloaddition (CuAAC) and photoinitiated thiol–ene coupling, monofunctional and bifunctional peptidodendrimer conjugates were obtained. The conjugates are biocompatible and demonstrate no toxicity to cells at biologically relevant concentrations. Furthermore, the orthogonal addition of multiple copies of two different antiviral peptides on the surface of a single dendrimer allowed the resulting bioconjugates to inhibit Herpes simplex virus type 1 at both the early and the late stages of the infection process. The presented work builds on further improving this attractive design to obtain a new class of therapeutics. 

We report poly(isocyanide)-based random copolymers (co-PIC) featuring alkoxycarbonyl-based side-chains synthesized via the metal-catalyzed controlled polymerization of chiral and achiral isocyanide monomers. The pyridine-functionalized achiral monomer provides functional sites while the chiral monomer drives the formation of a one-handed preferred helix. The side-chain functionalized helical polymer undergoes self-assembly with palladated pincer ligands, as evidenced by 1H NMR and UV-Vis spectroscopies. Circular dichroism (CD) spectroscopy confirms that the side-chain self-assembly does not affect the backbone helicity. We construct supramolecular helical brush copolymers via the metal coordination of the co-PIC backbone with telechelic poly(styrene)s. 1H NMR and UV-Vis spectroscopies confirm the metal coordination, and CD measurements suggest that the backbone retains its helical conformation. Additionally, viscometry measurements verify the formation of high molecular weight polymers while dynamic light scattering confirms the increasing hydrodynamic radii of the resulting supramolecular brush copolymers. Our methodology constructs complex 3D materials with fully synthetic, secondary structure containing building blocks. We view this as a platform for building architecturally controlled 3D supramolecular materials with high degrees of complexity. 

We report the first heterotelechelic helical poly(methacrylamide) (PMAc) bearing orthogonal supramolecular binding sites on its chain-ends synthesized through a combination of reversible addition–fragmentation chain-transfer (RAFT) polymerization and thiol–bromo “click” chemistry. The heterotelechelic PMAc was assembled with two monotelechelic polymers featuring different secondary structures, namely a coil-like poly(styrene) and a helical poly(isocyanide), resulting in the formation of a coil–helix–helix supramolecular triblock copolymer through orthogonal metal coordination and hydrogen bonding interactions. Triblock assembly was confirmed through 1 H NMR spectroscopy, isothermal titration calorimetry (ITC) and viscometry. The individual polymer blocks retained their secondary structures in the final triblock copolymer, as evidenced by circular dichroism (CD) spectroscopy. Our synthetic strategy expands the toolbox of triblock copolymers featuring structural motifs similar to the ones found in proteins and provides the potential for the development of other complex multifunctional polymeric ensembles.