Multicomponent Reactions in Polymer Chemistry Utilizing Heavier Main Group Elements

Dynamic Chalcogen Squares for Material and Topological Control over Macromolecules

Herein we introduce chalcogen squares via selenadiazole motifs as a new class of dynamic supramolecular bonding interactions for the modification and control of soft matter materials. We showcase selenadiazole motifs in supramolecular networks of varying primary chain length prepared through polymerization using tandem step-growth/Passerini multicomponent reactions (MCRs). Compared to controls lacking the selenadiazole motif, these networks display increased glass transition temperatures and moduli due to the chalcogen bonding linkages formed between chains. These elastomeric networks were shown to autonomously heal at room temperature, retaining up to 83 % of the ultimate tensile strength. Lastly, we use post-polymerization modification via the Biginelli MCR to add selenadiazole motifs to narrowly dispersed polymers for controlled topology in solution. Chalcogen squares via selenadiazoles introduce an exciting exchange mechanism to the realm of dynamic materials.

Multicomponent Synthesis of Poly(α-aminophosphine chalcogenide)s and Subsequent Depolymerization

Multicomponent reactions of primary phosphines (R-PH2), diimines (R'-N═C(H)-R-(H)C═N-R'), and chalcogens (O2, S8) generate poly(α-aminophosphine chalcogenide)s (4-7) through step-growth polymerization. Characterization of the linear polymers using 31P{1H} diffusion-ordered NMR spectroscopy (DOSY) experiments aided in determining the molecular weight (Mw) of the material. Subjecting the polyphosphine oxide or sulfide to reducing conditions in the presence of a Lewis acid resulted in complete depolymerization of the polymers, quantitatively releasing the 1° phosphine and diimine (2) starting materials, with concomitant reduction of diimine to diamine (9).

Are Metal Halide Perovskite Solar Cells Ready for Space Applications?

The appeal of metal halide perovskite solar cells (PSCs) has been widely demonstrated in the field of photovoltaic technology. On account of the excellent optical and electrical properties, as well as compatibility with flexible substrates, the PSCs also hold the highest record of specific power for lightweight solar cell devices, suggesting excellent promise in space applications. Hence, there is increasing interest in the performance of PSCs in space environments where radiation beams and thermal cycling can cause extreme stress on the devices. In this Perspective, we provide a brief summary of the research on PSCs for space applications. The radiation tolerance and thermal stability of PSCs and the fundamental mechanisms are discussed and analyzed. Key challenges facing PSC technology toward future space applications are demonstrated. This Perspective features the prospect of PSCs as the next frontier in space PV technology.

One-pot cascade polycondensation and Passerini three-component reactions for the synthesis of functional polyesters

A one-pot cascade four-component polymerization and post-polymerization modification reaction is introduced to synthetic polymer chemistry.

De Novo Design of Entropy-Driven Polymers Resistant to Bacterial Attachment via Multicomponent Reactions

Nonbactericidal polymers that prevent bacterial attachment are important for public health, environmental protection, and avoiding the generation of superbugs. Here, inspired by the physical bactericidal process of carbon nanotubes and graphene derivatives, we develop nonbactericidal polymers resistant to bacterial attachment by using multicomponent reactions (MCRs) to introduce molecular "needles" (rigid aliphatic chains) and molecular "razors" (multicomponent structures) into polymer side chains. Computer simulation reveals the occurrence of spontaneous entropy-driven interactions between the bacterial bilayers and the "needles" and "razors" in polymer structures and provides guidance for the optimization of this type of polymers for enhanced resistibility to bacterial attachment. The blending of the optimized polymer with commercially available polyurethane produces a film with remarkably superior stability of the resistance to bacterial adhesion after wear compared with that of commercial mobile phone shells made by the Sharklet technology. This proof-of-concept study explores entropy-driven polymers resistant to bacterial attachment via a combination of MCRs, computer simulation, and polymer chemistry, paving the way for the de novo design of nonbactericidal polymers to prevent bacterial contamination.

Passerini Multicomponent Reactions Enabling Self-Reporting Photosensitive Tetrazole Polymers

We introduce the synthesis of photosensitive tetrazole monomers via Passerini multicomponent reactions (MCRs). We exploit the MCR's tolerance toward various functional groups under mild, catalyst-free conditions in a one-pot reaction setup to generate tetrazole-containing monomers featuring a methacrylic moiety, which enables their subsequent reversible addition-fragmentation chain transfer (RAFT) polymerization. By employing tetrazoles with either a 4-methoxy phenyl or a pyrene substituent, further modifications of the polymers in a wavelength-orthogonal, self-reporting fashion upon irradiation with either UV or visible light become possible.