Enhanced solar-to-chemical energy conversion of graphitic carbon nitride by two-dimensional cocatalysts

EnergyChem, Год журнала: 2021, Номер 3(2), С. 100051 - 100051

Опубликована: Янв. 28, 2021

Язык: Английский

---

Fast Carbon Isotope Exchange of Carboxylic Acids Enabled by Organic Photoredox Catalysis

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(5), С. 2200 - 2206

Опубликована: Янв. 28, 2021

Carbazole/cyanobenzene photocatalysts promote the direct isotopic carboxylate exchange of C(sp3) acids with labeled CO2. Substrates that are not compatible transition-metal-catalyzed degradation–reconstruction approaches or prone to thermally induced reversible decarboxylation undergo incorporation at room temperature in short reaction times. The radiolabeling drug molecules and precursors [11C]CO2 is demonstrated.

Язык: Английский

---

Chain-Extending Modification for Value-Added Recycled PET: A Review

Polymer Reviews, Год журнала: 2022, Номер 62(4), С. 860 - 889

Опубликована: Янв. 31, 2022

The global environmental issues caused by plastic incineration are continuously increasing, along with the demand for polyethylene terephthalate (PET)—27 million metric tons of PET was demanded in 2020. Therefore, recycling has emerged as core circular economy. In particular, methods categorized into two pathways: mechanical and chemical recycling, wherein is more efficient than recycling. However, undergoes heat-induced degradations during such reduction molecular weight (MW) viscosity. feasible required to overcome challenges. This article details process using a chain-extending extrusion method. Accordingly, various chain extenders (CEs) were reviewed identify their effects on recycled (rPET) properties reactive processes. Moreover, we detailed recent progress method used based CEs rPET properties.

Язык: Английский

---

CO₂ Chemisorption Behavior in Conjugated Carbanion-Derived Ionic Liquids via Carboxylic Acid Formation

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(47), С. 21658 - 21663

Опубликована: Ноя. 15, 2022

Superbase-derived task-specific ionic liquids (STSILs) represent one of the most attractive and extensively studied systems in carbon capture via chemisorption, which obtained CO2 uptake capacity has a strong relationship with basicity anions. High energy input desorption side reactions caused by anions are still unsolved issues. The development other customized STSILs leveraging an alternative driving force to achieve efficient chemisorption/desorption is highly desirable yet challenging. In this work, carbanion-derived were developed for chemisorption carboxylic acid formation pathway. STSIL deprotonated malononitrile molecule ([MN]) as anion exhibited much higher than derived from 2-methylmalononitrile ([MMN]). Notably, trend was opposite their ([MN] < [MMN]). Detailed characterization products, supported density functional theory simulations spectra calculations reaction energetics, demonstrated that formed upon reacting proton transfer [MN]-derived but not case [MMN] due lack α-H. preference product over carboxylate driven extended conjugation among central sp2 carbon, as-formed acid, two nitrile groups. achievements made work provide design principle CO2-integrated product.

Язык: Английский

---

Late-Stage Carbon-14 Labeling and Isotope Exchange: Emerging Opportunities and Future Challenges

JACS Au, Год журнала: 2022, Номер 2(6), С. 1234 - 1251

Опубликована: Июнь 7, 2022

Carbon-14 (14C) is a gold standard technology routinely utilized in pharmaceutical and agrochemical industries for tracking synthetic organic molecules providing their metabolic safety profiles. While the state of art has been dominated decades by traditional multistep approaches, recent emergence late-stage carbon isotope labeling provided new avenues to rapidly access carbon-14-labeled biologically relevant compounds. In particular, development exchange represented fundamental paradigm change, opening way unexplored transformations. this Perspective, we discuss developments field with critical assessment literature. We subsequently research directions future challenges within evolving field.

Язык: Английский

---

Regiodivergent electroreductive defluorinative carboxylation ofgem-difluorocyclopropanes

Green Chemistry, Год журнала: 2023, Номер 25(8), С. 3095 - 3102

Опубликована: Янв. 1, 2023

A regiodivergent electrochemical defluorocarboxylation of gem -difluorocyclopropanes is realized, providing access to branched and linear carboxylated monofluorinated alkenes.

Язык: Английский

---

Polyurethanes from Direct Organocatalytic Copolymerization of p‐Tosyl Isocyanate with Epoxides

Angewandte Chemie International Edition, Год журнала: 2020, Номер 60(3), С. 1593 - 1598

Опубликована: Сен. 29, 2020

Abstract The direct copolymerization of p ‐tosyl isocyanate (TSI) with epoxides, initiated by onium salts in the presence trialkylborane, to produce polyurethanes is reported. rate and (regio)selectivity were investigated relation trialkylborane initiator used. Under optimized conditions such copolymerizations have been successfully performed for a wide range including ethylene oxide, propylene 1‐octene cyclohexene allyl glycidyl ether. These afford new category polyurethanes, clear side products as cyclic oxazolidinone, isocyanurate, poly(isocyanate) linkages. experimental used this work are compatible those organocatalytic (co)polymerization other oxygenated monomers CO 2 , holding potential their terpolymerization development materials unprecedented properties.

Язык: Английский

---

Mechanochemical Release of N‐Heterocyclic Carbenes from Flex‐Activated Mechanophores

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(24), С. 13559 - 13563

Опубликована: Апрель 7, 2021

Abstract We have discovered a new flex‐activated mechanophore that releases an N‐heterocyclic carbene (NHC) under mechanical load. The design is based upon NHC‐carbodiimide (NHC‐CDI) adducts and demonstrates important first step toward designs capable of further downstream reactivities. Since the flex‐activation non‐destructive to main polymer chains, material can be subjected multiple compression cycles achieve iterative increases in activation percentage mechanophores. Two different NHC structures were demonstrated, signifying potential modularity design.

Язык: Английский

---

Modern Strategies for Carbon Isotope Exchange

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(36)

Опубликована: Апрель 19, 2023

In contrast to stable and natural abundant carbon-12, the synthesis of organic molecules with carbon (radio)isotopes must be conceived optimized in order navigate through hurdles radiochemical requirements, such as high costs starting materials, harsh conditions radioactive waste generation. addition, it initiate from small cohort available C-labeled building blocks. For long time, multi-step approaches have represented sole patterns. On other side, development chemical reactions based on reversible cleavage C-C bonds might offer new opportunities reshape retrosynthetic analysis radiosynthesis. This review aims provide a short survey recently emerged isotope exchange technologies that effective opportunity for late-stage labeling. At present, strategies relied use primary easily accessible radiolabeled C1-building blocks, dioxide, monoxide cyanides, while activation principles been thermal, photocatalytic, metal-catalyzed biocatalytic processes.

Язык: Английский

---

Mechanistic mapping of (CS2/CO2)/epoxide copolymerization catalysis leads to terpolymers with improved degradability

Cell Reports Physical Science, Год журнала: 2023, Номер 4(8), С. 101510 - 101510

Опубликована: Июль 21, 2023

The placement of main-group functionalities within polymers represents a strategy to access wide catalog materials but is limited by poor understanding the catalyst selection criteria and polymerization mechanism when moving down periodic table. Here, we study series new heterobimetallic carbon dioxide disulfide/epoxide copolymerization catalysts that allow for comparative mechanistic two ring-opening processes. We reveal distinct roles each metal plays are preserved from disulfide, maintaining activity selectivity across copolymerizations. Experimental computational studies show can be understood as structurally related insertion events interlinked central oxygen/sulfur scrambling reaction at propagating chain end. This facilitates synthesis dioxide-/carbon disulfide-/epoxide-derived terpolymers with improved degradability over parent dioxide/epoxide copolymers low levels sulfur incorporation.

Язык: Английский

---