Figure - available from: Polymer Bulletin
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UV-vis spectra of the cast film of polymer-1 (bold curve) and films of polymer-2a (hashed curve), polymer-2b (dotted curve), and polymer-2c (thin curve) sandwiched between quartz glass plates in air
Source publication
Polyphenylene (PP) with NH2 side groups, namely, polymer-1, was synthesized by the Pd-complex-catalyzed reaction of 2,5-dibromoaniline with 9,9-dihexylfluorene-2,7-diboronic acid bis(1,3-propanediol) ester. The reaction of polymer-1 with 1,1′-bis(2,4-dinitrophenyl)-4,4′-bipyridinium dichloride (salt-1) in 1:0.5, 1:1, and 1:2 molar ratios eliminated...
Citations
Renewable organic batteries represent a valuable option to store sustainably generated energy and can play a major role in phasing out current carbon-based energy production. Several approaches have emerged over the last 80 years that utilize organic redox materials as active components in batteries. In particular, polymers have gained considerable interest among numerous research groups due to their (1) fast redox chemistry, in comparison to conventional active materials, (2) straight-forward syntheses, and (3) tunable solubility, which represent favored properties for diverse electronic devices. Notably, the beginning of redox-active polymers is linked to the discovery of conductive polymers by Heeger, MacDiarmid and Shirakawa in 1977. Nevertheless, redox-active polymers were studied in 1944 making them a familiar class under the broader polymeric framework, which celebrate its 100th birthday in 2020, based on the pioneering publication by Staudinger in 1920. Since their beginning, redox-active polymers have evolved from an interesting phenomenon into a family of promising, tailor-made, battery materials that also made their way to commercialization. In this regard, this review focusses on the design of interesting polymeric, redox-active materials. Polymerization techniques are discussed regarding novel polymer architectures and utilitarian properties. The polymer architectures are subsequently analyzed within the application scenarios of solid-state batteries, pseudo-capacitors, and redox-flow batteries. Redox moieties are compared and an overview of diverse synthetic aspects as well as battery concepts for the optimal assembly of polymeric battery materials are given.
Dicationic quaternary salts of 4,4’-bipyridine, also referred to as the viologen family, are well known for their interesting redox chemistry, whereby they can be reversibly reduced into radical cationic and neutral moieties. Because of this ability to switch between different redox states, viologens have frequently been incorporated into covalent organic polymers (COPs) as molecular switches to construct stimuli-responsive materials. While many viologen-based COPs have been reported, hyper-conjugated insoluble COPs started to emerge fairly recently and have not been comprehensively reviewed. In this review, we investigate the design strategies employed in the synthesis of insoluble viologen-based COPs, which can be broadly classified as those with viologen in the backbone and those with viologen as pendant groups. Chemical reactions used in the synthesis of each category, including Sonogashira-Hagihara cross-coupling, Menshutkin and Zincke reactions, are highlighted. Diverse applications of these COPs are discussed with particular reference to the redox state of viologen in each material. Uses of these materials for gas adsorption and separation, organic and inorganic pollutant removal, catalysis, sensing and film fabrication are explored.
This Review details synthetic routes toward and properties of insoluble polymeric organic semiconductors obtained through desolubilization strategies. Typical applications include fixation of donor–acceptor bulk-heterojunction morphologies in organic photovoltaic cells, cross-linking of charge transport materials and active emitters in light emitting diodes or similar devices, and immobilization of morphologies in field effect transistors. A second important application is the structuring of organic semiconductors, using them as photoresists. After desolubilization, removal of the nonirradiated resist leads to elevated, micron-sized features of the semiconductor. In this Review, different strategies for desolubilization are covered. By photochemical or thermal cleavage of solubility-mediating groups such as esters, sulfonium salts, amides, ethers, and acetals or by retro-Diels–Alder reactions, volatile elimination products and the insoluble semiconductor are formed. In another case, desolubilization is achieved by cross-linking via functional groups present in the polymer side chains including vinyl, halide, silicone, boronic acid, and azide functionalities, which polymerize thermally or photochemically. Alternatively, small molecular additives such as photoacids, oligothiols, or oligoazides result in network formation in combination with compatible functional groups present in the immobilizable polymers. Advantages and disadvantages of the respective methods are discussed.
