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1. Multiscale simulation of plastic transformations: The case of base‐assisted dehydrochlorination of polyvinyl chloride

   https://doi.org/10.1002/aic.18559  

   Ezendu, Sophia; Soyemi, Ademola; Szilvási, Tibor (August 2024, AIChE Journal)

   Abstract Plastic transformations are critical to ongoing recycling and upcycling efforts, but the complexity of the reactions makes it difficult to understand the effect of individual factors on reaction rates and product distributions experimentally. In this work, we report on a multiscale simulation framework for studying polymer transformations that incorporates affordable high‐level coupled cluster calculations combined with benchmarked density functional theory calculations, detailed conformer search, and lattice‐based kinetic Monte Carlo simulations to provide the temporal and spatial evolution of the polymer during transformations. Our framework can match experimentally observed reaction times within an order of magnitudewithoutany parameter estimation in base‐assisted dehydrochlorination of polyvinyl chloride. We determine that the E2 reaction mechanism dominates the reaction and demonstrate that different structural defects can inhibit or promote directional polyene growth as well as affect the structure of the dehydrochlorination product. 

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2. Redox‐Neutral TEMPO Catalysis: Direct Radical (Hetero)Aryl C−H Di‐ and Trifluoromethoxylation

   https://doi.org/10.1002/anie.202009490  

   Lee, Johnny W.; Lim, Sanghyun; Maienshein, Daniel N.; Liu, Peng; Ngai, Ming‐Yu (September 2020, Angewandte Chemie International Edition)

   Abstract Applications of TEMPO^.catalysis for the development of redox‐neutral transformations are rare. Reported here is the first TEMPO^.‐catalyzed, redox‐neutral C−H di‐ and trifluoromethoxylation of (hetero)arenes. The reaction exhibits a broad substrate scope, has high functional‐group tolerance, and can be employed for the late‐stage functionalization of complex druglike molecules. Kinetic measurements, isolation and resubjection of catalytic intermediates, UV/Vis studies, and DFT calculations support the proposed oxidative TEMPO^./TEMPO⁺redox catalytic cycle. Mechanistic studies also suggest that Li₂CO₃plays an important role in preventing catalyst deactivation. These findings will provide new insights into the design and development of novel reactions through redox‐neutral TEMPO^.catalysis. 

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3. Highly selective transition-metal-free transamidation of amides and amidation of esters at room temperature

   https://doi.org/10.1038/s41467-018-06623-1  

   Li, Guangchen; Szostak, Michal (October 2018, Nature Communications)

   Abstract Amide chemistry has an essential role in the synthesis of high value molecules, such as pharmaceuticals, natural products, and fine chemicals. Over the past years, several examples of transamidation reactions have been reported. In general, transition-metal-based catalysts or harsh conditions are employed for these transformations due to unfavorable kinetics and thermodynamics of the process. Herein, we report a significant advance in this area and present the general method for transition-metal-free transamidation of amides and amidation of esters by highly selective acyl cleavage with non-nucleophilic amines at room temperature. In contrast to metal-catalyzed protocols, the method is operationally-simple, environmentally-friendly, and operates under exceedingly mild conditions. The practical value is highlighted by the synthesis of valuable amides in high yields. Considering the key role of amides in various branches of chemical science, we envision that this broadly applicable method will be of great interest in organic synthesis, drug discovery, and biochemistry. 

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4. Diaryliodonium Salts Facilitate Metal-Free Mechanoredox Free Radical Polymerizations

   https://doi.org/10.1039/D2SC00313A  

   Zeitler, Sarah Margaret; Chakma, Progyateg; Golder, Matthew (March 2022, Chemical Science)

   Mechanically-induced redox processes offer a promising alternative to more conventional thermal and photochemical synthetic methods. For macromolecule synthesis, current methods utilize sensitive transition metal additives and suffer from background reactivity. Alternative methodology will offer exquisite control over these stimuli-induced mechanoredox reactions to couple force with redox-driven chemical transformations. Herein, we present the iodonium-initiated free-radical polymerization of (meth)acrylate monomers under ultrasonic irradiation and ball-milling conditions. We explore the kinetic and structural consequences of these complementary mechanical inputs to access high molecular weight polymers. This methodology will undoubtedly find broad utility across stimuli-controlled polymerization reactions and adaptive material design. 

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5. Protein‐Engineered Functional Materials for Bioelectronics

   https://doi.org/10.1002/adfm.202006744  

   Chen, Min; Fu, Xuewei; Chen, Zhiping; Liu, Jin; Zhong, Wei‐Hong (October 2020, Advanced Functional Materials)

   Abstract Structural and compositional diversities of proteins generate a number of functions for fabricating novel and advanced materials. Recent progress in protein engineering endows flexible approaches and new functionalities, which makes the fabricated materials potentially applicable in a broad spectrum of fields. Such engineering strategies by applying proteins alone or together with other molecules derive numerous functional materials such as patterned nanometal materials/nanometallic compounds, well‐designed nanocomposites, etc. Advantages in materials’ tunability, property improvement (e.g., electronic and mechanical properties, etc.), functionalities, and biocompatibility have been demonstrated, thus providing alternatives to existing materials via conventional methods. This review summarizes and discusses the strategies of fabricating functional materials using proteins as the critical contributors. Benefiting from their versatility, proteins find their roles in engineering functional materials via acting as structure‐control agents, reaction agents, and battery components, which are emphasized in this review. The strategies of each group of functions are specifically detailed. Properties of protein‐engineered functional materials and their potential applications in the fields of microelectronics, energy storage and conversion, sensor devices, etc. are also reviewed. 

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