Article
Chemistry, Multidisciplinary
Manfei Zhou, Lijun Mao, Yan-Fei Niu, Xiao-Li Zhao, Xueliang Shi, Hai-Bo Yang
Summary: This study investigates the redox behavior and radical cation species of triphenylamines with various substituents. The results demonstrate that resonance hybrid and steric protection contribute to the stability of triphenylamine radical cations. Additionally, further oxidation leads to unexpected demethylation. These findings provide new insights into the unique redox properties of triphenylamines substituted with 4-anisyl groups.
CHINESE CHEMICAL LETTERS
(2022)
Article
Chemistry, Organic
Chunchen Liu, Guangwu Li, Hoa Phan, Ya Zou, Xuefeng Lu, Jishan Wu
Summary: Both molecules have a highly strained structure and exhibit open-shell singlet diradical character with a small singlet-triplet energy gap.
Article
Chemistry, Multidisciplinary
Parastoo Dalvand, Katia Nchimi Nono, Dinesh Shetty, Farah Benyettou, Zouhair Asfari, Carlos Platas-Iglesias, Mark A. Olson, Ali Trabolsi, Mourad Elhabiri
Summary: Two calix[4]arene systems can form [3]pseudorotaxanes when combined with CB[7] or CB[8], while [2]pseudorotaxanes based on CB[7] and CB[8] do not undergo decomplexation and dimerization under certain conditions.
Article
Chemistry, Multidisciplinary
Abel Cardenas Valdivia, Yasi Dai, Filippo Rambaldi, Joshua E. Barker, Justin J. Dressler, Zheng Zhou, Yikun Zhu, Zheng Wei, Marina A. Petrukhina, Michael M. Haley, Fabrizia Negri, Juan Casado
Summary: The electronic, optical, and solid state properties of a series of monoradicals, anions, and cations obtained from starting neutral diradicals have been studied. The properties of the neutral state, specifically the diradical character, are related to the properties of the radical redox forms. The analysis of their optical features has been carried out using molecular orbital and valence bond theories, and electronic UV-Vis-NIR absorption, X-ray solid-state diffraction, and quantum chemical calculations have been conducted.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Organic
Jie Qiu, Wei Li, Xiaofeng Li, Yongyong Cao, Cheng-Xue Pan, Huaifeng Li
Summary: In this study, a radical-based annulation of azomethine imines utilizing visible-light photoredox catalysis is described for the first time. This strategy enables the synthesis of dinitrogen-fused saturated six-membered cyclic products that have traditionally been difficult to access, exhibiting exceptional cis diastereoselectivity.
Article
Chemistry, Multidisciplinary
Tzu-Yang Huang, Matthew J. Crafton, Yuan Yue, Wei Tong, Bryan D. McCloskey
Summary: This study deconvolutes the mixed redox processes in a Ni-based DRX material, revealing a much lower Ni oxidation efficiency than initially designed due to the competition of oxygen redox. The chemical approach presented in this work and its future extension can resolve and quantify various mixed redox processes in different DRX, allowing clear correlations among material design, deconvoluted redox capacities, and battery performance.
ENERGY & ENVIRONMENTAL SCIENCE
(2021)
Article
Plant Sciences
Wenli Lei, Yuyang Song, Ai Long, Yanyan Que, Shuzhong He, Hang Zhong, Yang Chen
Summary: This study investigates the stereoselective cycloaddition reactions between allenyl ethers and substituted furans induced by chiral auxiliaries, showing significant stereoselectivity and regioselectivity. The generated optical cycloadducts with an oxygen-substituted seven-membered ring framework exhibit moderate antiproliferative effects towards T47D cells.
FRONTIERS IN PLANT SCIENCE
(2022)
Article
Polymer Science
Noemie Gil, Baptiste Caron, Didier Siri, Julien Roche, Slim Hadiouch, Douriya Khedaioui, Stephane Ranque, Carole Cassagne, Damien Montarnal, Didier Gigmes, Catherine Lefay, Yohann Guillaneuf
Summary: In this study, degradable high molar mass polystyrene was successfully prepared by incorporating a cyclic monomer into the polymer backbone through copolymerization. The thermal and mechanical properties of the polystyrene were not significantly altered. Moreover, the degraded polystyrene could be broken down into soluble oligomers through catalysis and base activation. The research demonstrated the potential applications of this copolymerization system in the phototriggered decomposition of polystyrene in solution and the degradation of cross-linked polystyrene networks into soluble side products.
Article
Chemistry, Multidisciplinary
Yasuhiro Hashimoto, Genki Horiguchi, Hidehiro Kamiya, Yohei Okada
Summary: The design of photocatalytic processes, especially the electron transfer-based [2+2] cycloaddition reaction, plays a crucial role in organic synthesis. Electron transfer is essential for reaction design and occurs not only between the substrate and the photocatalyst but also within and between molecules. The photocatalyst generates radical cations that are trapped by alkenes, leading to the formation of cyclobutyl radical cations. These radical cations are then reduced by aryl rings via intramolecular electron transfer, resulting in the formation of cyclobutane rings. The outcome of the reaction is influenced by the substitution of the aryl ring and the linker connecting the aryl ring to the enol ether. Carefully designed substrates exhibit high efficacy in photocatalytic cycloaddition.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Yilin Chen, Jiancheng Li, Yiling Zhao, Li Zhang, Gengwen Tan, Hongping Zhu, Herbert W. Roesky
Summary: In this study, compound 2 undergoes charge transfer reactions with various reagents, leading to the formation of stable radical cation and dication species of the 1,4-disilabenzene. Additionally, compound 2 also undergoes oxidative addition reactions with group 16 elements such as O, S, and Se.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Lukasz Orzel, Dorota Rutkowska-Zbik, Rudi van Eldik, Leszek Fiedor, Grazyna Stochel
Summary: Copper(II) chloride in organic solvents exhibit extensive speciation that allows switching between different chlorophyll transmetalation pathways, with one pathway particularly suitable for forming and stabilizing chlorophyll pi-cation radicals due to its unique redox cycling. In the presence of a proton donor, the system shows behavior similar to superoxide dismutase (SOD), and chlorophyll acts as an electron transfer mediator regardless of light conditions.
Article
Chemistry, Multidisciplinary
Muhammad Abdul Rahim, Muhammad Imran, Saadia Ambreen, Faima Atta Khan, Joe M. Regenstein, Fahad Al-Asmari, Sadaf Oranab, Muhammad Nadeem, Imtiaz Hussain, Muhammad Zubair Khalid, Waseem Khalid, Moneera O. Aljobair, Isam A. Mohamed Ahmed
Summary: This study investigated the effect of mixing fish oil with chia seed oil on the stability of fish oil and optimized the preparation conditions of spray-dried microcapsules using response surface methodology. The blend of fish oil and chia seed oil increased the oxidative stability of fish oil and encapsulation improved the stability and bioactivity of antioxidants. The optimized conditions for spray-dried microcapsules were determined. These microcapsules can be used in food matrices due to their therapeutic and nutritional properties.
Article
Polymer Science
Weikai Chen, Ziyang Zhou, Dagui Chen, Yinghua Li, Qin Zhang, Jiacan Su
Summary: This review focuses on MMP-cleavable peptides, polymers, functional modifications, and crosslinking reactions in bone regeneration, discussing the applications, perspectives, and limitations of MMP-cleavable peptides-based hydrogels.
Article
Chemistry, Physical
Jun-Ying Feng, Yuan-Pern Lee, Henryk A. Witek, Takayuki Ebata
Summary: The structures and reactions of pyridine cluster cations generated at specific ionization energy were investigated using infrared action spectroscopy. Proton and deuteron migration during formation and dissociation of the cluster cations were observed, with reactions involving alpha-distonic cation intermediates and proton migration pathways, respectively. Infrared spectra indicated that the clusters consist of a core covalently bound with additional pyridines via hydrogen bonds and/or weak dispersive interactions.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Organic
Haruka Morizumi, Kaii Nakayama, Yoshikazu Kitano, Yohei Okada
Summary: In this study, a possible radical cation Diels-Alder reaction using an enol ether as an electron-rich dienophile was revealed through a rationally designed redox tag strategy. The reaction was driven by both intermolecular and intramolecular electron transfers, which were effectively achieved through electrochemical and TiO2 photochemical approaches.
Article
Chemistry, Multidisciplinary
Christopher S. Gravatt, Luis Melecio-Zambrano, Tehshik P. Yoon
Summary: The sole method available for the photocycloaddition of unconjugated aliphatic alkenes is the Cu-catalyzed Salomon-Kochi reaction. A new catalyst system with superior reactivity and photostability has been designed, offering significantly expanded substrate scope and highlighted through the preparation of the natural products sulcatine G and perforatol.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Nicholas L. Reed, Grace A. Lutovsky, Tehshik P. Yoon
Summary: This study demonstrates that Cu(II)-mediated radical-polar crossover enables efficient photocatalytic oxidative heterofunctionalization reactions between bulky alkenes and various nucleophilic partners. It shows that Cu(II) salts are ideal terminal oxidants for photoredox applications, and the combination of photocatalytic substrate activation and Cu(II)-mediated radical oxidation can address challenges in catalytic oxidation chemistry.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Organic
Spencer O. Scholz, Jesse B. Kidd, Luca Capaldo, Niecia E. Flikweert, Rowan M. Littlefield, Tehshik P. Yoon
Summary: This study presents a photosensitized [2 + 2] cycloaddition reaction for the straightforward access to complex cyclobutane scaffolds. Mechanistic studies suggest an activation mode involving energy transfer to the styrenyl alkene rather than the vinyl boronate ester.
Article
Chemistry, Organic
Xiao Dong, Qi Yukki Li, Tehshik P. Yoon
Summary: The research shows that in designing photochemical reactions, not only the excited-state oxidation potential is important, but also the oxidation and reduction potentials of the photocatalyst are crucial for the reaction outcome. This highlights the importance of holistic considerations in designing photochemical reactions.
Review
Chemistry, Multidisciplinary
Matthew J. Genzink, Jesse B. Kidd, Wesley B. Swords, Tehshik P. Yoon
Summary: Asymmetric photocatalysis is a major research topic in contemporary synthetic organic chemistry. However, the discovery of general strategies for highly enantioselective photochemical reactions has been a recent development, leading to a somewhat limited variety of stereocontrolled photoreactions. This review summarizes the chiral catalyst structures that have been studied for solution-phase asymmetric photochemistry, providing insight into the logic required for highly effective stereocontrolled photocatalysis.
Article
Chemistry, Multidisciplinary
Steven J. Chapman, Wesley B. Swords, Christine M. Le, Ilia A. Guzei, F. Dean Toste, Tehshik P. Yoon
Summary: Stereoinduction in complex organic reactions often involves the interaction of multiple stereocontrol elements, with the potential for significant cooperative effects. This study presents a strategy for enantioselective photocycloaddition reactions using a tandem chiral photocatalyst/Bronsted acid approach. The matched and mismatched chiral catalyst pairs show different reaction rates and enantioselectivities, suggesting the importance of similar matched/mismatched effects in other types of enantioselective dual-catalytic photochemical reactions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Qi Yukki Li, Samuel N. Gockel, Grace A. Lutovsky, Kimberly S. DeGlopper, Neil J. Baldwin, Mark W. Bundesmann, Joseph W. Tucker, Scott W. Bagley, Tehshik P. Yoon
Summary: Reactions that allow for the formation of carbon-nitrogen, carbon-oxygen, and carbon-carbon bonds are crucial in synthetic chemistry. This study presents a copper-mediated, net-oxidative decarboxylative coupling reaction under visible-light irradiation, which enables the conversion of substrates without requiring harsh reaction conditions.
Article
Chemistry, Organic
Wesley B. Swords, Steven J. Chapman, Heike Hofstetter, Anna L. Dunn, Tehshik P. Yoon
Summary: LED-NMR is a rapid and convenient method for directly monitoring the in-situ photocatalytic reaction. The study using LED-NMR reveals a change in mechanism between reactions conducted at different temperatures. These results highlight the sensitivity of photocatalytic reaction mechanisms to precise reaction conditions.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Andrew Whyte, Tehshik P. P. Yoon
Summary: Carboxylic acids are attractive building blocks in synthetic chemistry due to their stability, abundance, and structural diversity. The ketonization reaction, which combines two carboxylic acids to produce a ketone, has been underutilized due to harsh reaction conditions and lack of selectivity. We report a new strategy that utilizes metallaphotoredox to selectively generate unsymmetrical ketones by cross-ketonization of structurally dissimilar carboxylic acids.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Zebediah C. Girvin, Laura F. Cotter, Hyung Yoon, Steven J. Chapman, James M. Mayer, Tehshik P. Yoon, Scott J. Miller
Summary: High selectivity in photochemical reactions can be achieved by controlling the transition state.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Organic
Grace A. Lutovsky, Ellie F. Plachinski, Nicholas L. Reed, Tehshik P. Yoon
Summary: A method for allylic amination using photoredox activation and Cu(II)-mediated radical-polar crossover is described. This strategy allows the synthesis of a range of structurally varied allylic amines. The regioselectivity of this process complements that of conventional methods for allylic amination.
Article
Chemistry, Organic
Riley M. Kelch, Andrew Whyte, Eunji Lee, Tehshik P. Yoon
Summary: Here, it is demonstrated that the addition of Lewis acid co-catalysts can greatly expand the range of alkenes that can participate in the photosensitized visible-light De Mayo reaction. Mechanistic studies indicate that the primary advantage of Lewis acid is not on substrate sensitization, but rather on bond-forming steps after energy transfer, illustrating the versatile effects Lewis acids can have on sensitized photoreactions.
Article
Chemistry, Multidisciplinary
Grace A. Lutovsky, Samuel N. Gockel, Mark W. Bundesmann, Scott W. Bagley, Tehshik P. Yoon
Summary: In this study, a direct decarboxylative cross-coupling of native carboxylic acids with nucleophilic coupling partners mediated by inexpensive and non-toxic Fe(III) salts was reported. This method involves an initial photochemical decarboxylation followed by radical-polar crossover, enabling the construction of diverse carbon-carbon, carbon-oxygen, and carbon-nitrogen bonds with remarkable generality.
Article
Chemistry, Multidisciplinary
Matthew J. J. Genzink, Matthew D. D. Rossler, Herman Recendiz, Tehshik P. P. Yoon
Summary: Chiral acid catalysts are shown to promote highly selective visible-light photocycloadditions, leading to the synthesis of truxinate natural products. This general approach allows for the efficient synthesis of dimeric and pseudodimeric cyclobutane natural products with excellent enantioselectivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Review
Chemistry, Organic
Grace A. Lutovsky, Tehshik P. Yoon
Summary: Photochemistry provides a crucial platform for the discovery of useful synthetic transformations, but developing new oxidative photoreactions has proven to be challenging. This review highlights recent reaction methods that utilize Cu(II) oxidation in combination with photochemical activation of substrates or use Cu(II) salts as both the active chromophore and terminal oxidant.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
