Multicomponent Reactions in Polymer Science

The rapid development of science and technology has brought urgent demand for diversity in polymer structures functionalities, the pursuit new polymerizations is constant goal chemistry. Multicomponent reactions (MCRs)—reactions three or more starting materials able to generate a single product one-pot manner—feature series advantages such as simple reactants, easy operation, mild conditions, high efficiency, environmental benefit, and, most importantly, great structures. Since first report Strecker synthesis amino acids from three-component reaction aldehydes, hydrogen cyanide, amines 1850,[1] large number MCRs have been reported including Mannich reaction, Passerini Ugi Biginelli Hantzsch Kabachnik–Fields Debus–Radziszewski many more. gradually developed into powerful tools efficiently construct libraries compounds with structural diversity, found applications organic synthesis, combinational chemistry, pharmaceutical industry.[2] Attracted by opportunity what could bring science, considerable efforts made utilize despite challenges preparation bi-/multi-functional monomers, polymerization specificity, solubility, control molecular weight. During past decade, some pioneering works progress polymers economically through multicomponent (MCPs) post-polymerization modification via MCRs. In early contributions, Meier co-workers polyesters amide moieties their side chain combination olefin metathesis,[3] Li utilized prepare sequence-controlled poly(ester-amide) process,[4] Tang an A3-coupling alkynes, amines,[5] Choi Cu(I)-catalyzed MCP sulfonyl azides, amines,[6] Endo prepared poly(thiourethane-phenylenevinylenesulfide)s amines, dithiocarbonates chemoselective nucleophilic radical additions,[7] Theato poly(N-sulfonylamidine) derivatives MCR terminal azide, amine,[8] Du Prez double poly(N-isopropyl acrylamide) ring-opening thiolactone primary amine subsequent Michael addition generated thiol groups acrylate.[9] Later, developed, used post-modification polymers. Compared classic polymerizations, besides those benefits inherent nature MCRs, MCPs also feature unique advantages, structure functionality, facile tuning backbone topological structures, strong designability procedures conditions. There are few recent reviews summarizing advances this field emphasis on topics isocyanide-based MCPs,[10] alkyne-based MCPs,[11] alkyne azide-based MCPs,[12] reaction,[13] reaction,[14] Debus-Radziszewski applied synthesis,[15] well sulfur-containing polymers.[16] With involving modification, while it impossible include all ongoing prosperous field, special issue Macromolecular Rapid Communications introduces state-of-art area representative examples, describing aiming provide inspiring source future work. Thankfully, synthetic experts effort complete work succeed contribute challenging situation caused Covid-19 pandemic. This composed eleven research articles eight overview articles, covering important aspects area. extensively investigated four-component reaction. Take carboxylic acid, isocyanide, oxo-component (aldehyde ketone) example, exploited multifunctional RAFT agents, star-shaped unimolecular micelles, linear polymers.[10] Based other progresses synthesize functional For Meier, Alexander, further versatility amphiphilic diblock copolymers, which be self-assembled polymersomes serve versatile drug carriers encapsulate both hydrophobic molecules within bilayer hydrophilic aqueous core (2000321). Koyama four-center aldehydes/ketones, alkyl ammonium salt, ambident molecule comprising isocyanide potassium carboxylate highly viscoelastic polypeptides elastin-mimetic acid sequence (2000480), these alternating peptides exhibited excellent adhesive properties, strength, re-adhesion capacity, shear-induced adhesion. Tao co-workers’ review (2000515), they summarized application acid-based polypeptoids sequence-defined polypeptoids. co-worker's (2000459), four strategies applying monomer-to-polymer strategy, polycondensation, post-modification, protein conjugation, formaldehyde detection, carrier, anti-bacterial adhesion summarized. Sui fabrication fluorescent cellulosic surface acetoacetylation cotton fabrics, followed obtained acetoacetyl-bearing fabrics acetate water under ambient temperature (2000496). Polymer chemists introduce design reactions, catalysts, functionalities. Of potential alkynes possess rich chemistry various construction that cannot accessed methods. Han, Lam, Tang, (2000386), heterochain trivalent Group 15 elements-containing polymers, chalcogen-containing containing 16 elements, halogen-containing Most currently conducted transition-metal trend develop metal-free conditions activated monomers. Hu, designed group-activated monomers catalyst-free propiolic acids, benzylamines, organoboronic condition, affording poly(propargylamine)s yields weights, good solubility processibility, thermal stability light refractivity, photophysical properties (2000633). Through ester cyclopolymerization diisocyanides, 1,4-dibromo-2,3-butanedione described Shi, Dong, (2000463), iminofuran-containing yields, stability. Natural reagents O2, H2O, CO2, S8 can abundant, nontoxic, economic, environmentally friendly, sustainable incorporated building blocks products. Qin, (2000547) summarizes using CO2 one catalytic systems, chemical engineering products discussed. Yan triarylborane, triarylphosphine, double-cross-linked gel based frustrated Lewis pair network, permanent crosslinks dynamic gas-bridged connections, possesses CO2-dependent mechanical reinforcement self-healing ability (2000699). Mutlu, Theato, article, elemental sulfur, waste modern oil gas refineries, adopted monomer sulfur-based polycondensation diketone presence aniline Brønsted produce polythiophenes (2000695). Other reactivity property MCPs. Meldrum's six-membered heterocycle, two symmetric groups, active methylene group susceptible electrophilic attack attack. Zhang, You, Hong, hence dialdehyde, diindole proline catalyst, complex well-defined proved tool different one-step (2000610). enable terms composition, Tuten Barner-Kowollik's (2000495), 13-16 elements involved By incorporation less traditional main boron, phosphorous, selenium not readily achieved only C, N, and/or O obtained. recently extended non-conjugated conjugated Dong article (2000646), efficient syntheses structurally π-conjugated classified categories: branched module approaches, where backbones fashion, respectively, transformative approach non-aromatic units multiple converted aromatic backbones. Moreover, variation combinations another advantage monodisperse block co-macromolecules iterative cycle reductive hydrogenolysis, octaethylene glycol monomethyl ether, coupling scaffold (2000467). Calvo, Wagener, Sumerlin, hyperbranched aminobisphosphonic reversible addition-fragmentation transfer self-condensing vinyl acrylamide-functional monomer, introduction aminobisphosphonate Kabachnick-Fields (2000578). functionalities actively explored. instance, Song dithiol, formaldehyde, secondary diamine water-soluble polycations tertiary cationic segments bind DNA, thioether scavenge reactive oxygen species reduce toxicity, hydroxyl shield positive charges, improve order promising nonviral gene delivery vectors transfection efficiency relatively low cytotoxicity (2000464). (2000471), utilization aggregation-induced emission (AIE) adopting AIEgen-containing situ generation AIEgen summarized, AIE-active products, stimuli-responsive materials, chemosensors, bioapplications, introduced. Liu, Wei, introduced latest about Kabachnik-Fields MALI biomedical adsorptive polymeric composites (2000563). demonstrated very diversified advanced become branch It anticipated inspire material scientists accelerate methodology materials. A. R. (Mike) studied Regensburg (Germany) received his Ph.D. degree Eindhoven University Technology (The Netherlands) 2006. After stays Emden Potsdam, he was appointed full professor at Karlsruhe institute (KIT) 2010. He several awards associate editor ACS Sustainable Chemistry & Engineering. His interests use derivatization renewable resources novel defined macromolecular architectures, often approaches Rongrong Hu her B.S. Peking 2007 Hong Kong Science (HKUST) 2011. She study HKUST during 2012–2014. joined Stake Key Laboratory Luminescent Materials Devices South China 2014 promoted 2016. Chemistry. Her current focused Ben Zhong Kyoto 1988, then postdoctoral Toronto 1989–1994. Department 1994 chair 2008. Stephen K. C. Cheong Professor Science, Chair Chemistry, Chemical Biological Engineering HKUST. elected Chinese Academy Sciences (CAS), Royal Society (RSC), Asia Pacific (APAM), World Advancement Developing Countries (TWAS), International Union Societies Biomaterials (IUSBSE). now serving Editor-in-Chief Aggregate. theranostics.