Article
Chemistry, Physical
Julia A. Turner, Nicholas Rosano, Daniel J. Gorelik, Mark S. Taylor
Summary: The combined action of a photoredox catalyst, a hydrogen atom transfer mediator, and a hydrogen bond acceptor cocatalyst has been used to successfully transform pyranoside-derived esters into ketodeoxysugars, which are important precursors for synthesizing rare sugar components. Computational studies support a radical lyase-like mechanism for this transformation involving 1,2-acyloxy migration in the radical intermediate.
Article
Chemistry, Multidisciplinary
Meiling Xu, Xu Jing, Bin Sun, Cheng He, Joost N. H. Reek, Chunying Duan
Summary: The use of a supramolecular strategy to encapsulate single catalysts and substrates in a urea-functionalized Fe4L6 cage allows for effective control of catalyst activity and selectivity. The unique structure of the cage enables the catalyst to function solely through pi activation of the substrate, resulting in significant selectivity, and the encapsulated catalyst shows higher activity compared to the free analogue.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Sewon Oh, Erin E. Stache
Summary: Polystyrene upcycling is crucial for reducing plastic waste, and photooxidative degradation is an effective method for converting polystyrene into valuable compounds. Investigating the mechanism of this degradation process is important in understanding the formation of different small molecules. By studying the reactivity differences between chlorine and bromine radicals, it was found that chlorine radical mainly produces benzoic acid, while bromine radical shows a preference for acetophenone. Further mechanistic studies revealed that activation of C-H bonds and hydrogen atom transfer are essential for acetophenone formation. Exogenous bromine sources were added to increase HBr concentration and improve acetophenone yield, becoming the major degradation product. These insights into polystyrene degradation mechanism will enable enhanced product selectivity.
Article
Chemistry, Multidisciplinary
Mayukh Bhadra, Wesley J. Transue, Hyeongtaek Lim, Ryan E. Cowley, Jung Yoon C. Lee, Maxime A. Siegler, Patrick Josephs, Gerald Henkel, Markus Lerch, Siegfried Schindler, Adam Neuba, Keith O. Hodgson, Britt Hedman, Edward Solomon, Kenneth D. Karlin
Summary: This study focused on the central role of cupric superoxide intermediates in hormone and neurotransmitter biosynthesis, investigating the impact on enzyme characteristics. A model of cupric superoxide and its reactivity were described, shedding light on the O-2-binding behavior and redox activity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Dung L. Golden, Chaofeng Zhang, Si-Jie Chen, Aristidis Vasilopoulos, Ilia A. Guzei, Shannon S. Stahl
Summary: Copper-catalyzed radical-relay reactions offer a versatile strategy for selective C-H functionalization; however, excessive C-H substrates are often needed when using peroxide-based oxidants. In this study, a photochemical approach using a Cu/2,2'-biquinoline catalyst was developed to overcome this limitation and achieve benzylic C-H esterification with limited C-H substrate. Mechanistic studies revealed that blue-light irradiation promotes carboxylate-to-copper charge transfer, leading to the activation of peroxide and generation of alkoxyl radical hydrogen-atom-transfer species. This photochemical redox buffering provides a unique strategy to sustain Cu catalyst activity in radical-relay reactions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Siqi Liu, Yong-Liang Su, Tian-Yu Sun, Michael P. Doyle, Yun-Dong Wu, Xinhao Zhang
Summary: The study focuses on the addition of halomethyl radicals to form bioactive molecules, with an emphasis on understanding the reactivity and selectivity of carbon radicals in hydrogen atom transfer and halogen atom transfer reactions. Through the emerging data-driven strategy, correlations were explored, revealing that predicted selectivities align with experimental determinations. This work highlights the potential applications of informatic workflow in mining reaction rules.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Hannah E. Askey, James D. Grayson, Joshua D. Tibbetts, Jacob C. Turner-Dore, Jake M. Holmes, Gabriele Kociok-Kohn, Gail L. Wrigley, Alexander J. Cresswell
Summary: This study presents a method for the direct, modular, and sustainable preparation of alpha-(di)substituted gamma-arylamines using organophotoredox catalysis. The method is versatile, tolerating a broad range of functionalities, and can be scaled up to multigram quantities in continuous flow.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Indu Sekhar Roy, Malte Doentgen, Can Huang, Wassja Kopp, Kai Leonhard
Summary: Biohybrid fuels, including 1,3-dioxolane, offer a promising solution for greener transportation. However, there is limited data on the oxidation kinetics of 1,3-dioxolane. This study presents the reaction kinetics of O2 addition to 1,3-dioxolanyl radicals and compares it to similar fuel molecules. The dominant pathway following the oxidation of 1,3-dioxolanyl radicals is the ring-opening beta-scission reactions of the dioxolane hydroperoxy species.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Indu Sekhar Roy, Malte Doentgen, Can Huang, Wassja Kopp, Kai Leonhard
Summary: Biohybrid fuels, such as 1,3-dioxolane produced from inedible biomass, show promise in making transportation more environmentally friendly. However, there is limited data on the kinetics of low-temperature oxidation of 1,3-dioxolane. This study presents the reaction kinetics of O-2 addition to 1,3-dioxolanyl radicals and compares it to similar fuel molecules. The results show that the ring-opening beta-scission reactions dominate the oxidation of 1,3-dioxolanyl radicals.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Multidisciplinary
Hafiz Saqib Ali, Sam P. de Visser
Summary: This study investigates the selective reaction of taurine/alpha-ketoglutarate dioxygenase (TauD) and reveals that the second-coordination sphere and the protonation states of residues play a significant role in determining the enzyme selectivity. The presence of a single proton on the active site histidine residue can alter the regioselectivity of the reaction through electrostatic perturbations, affecting the bond strengths of taurine. The protein cage in TauD weakens the pro-R C-1-H bond, leading to a chemoselective reaction process that is accurately reproduced by large cluster models.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Correction
Chemistry, Physical
Wenqi Chen, Xuan Guo, Lifang Chen, Ruiming Zhang, Yan Li, Haisong Feng, Xuefei Xu, Xin Zhang
Summary: The article provides a corrected version of a kinetics study on hydrogen abstraction reactions of cyclopentane by hydrogen, methyl, and ethyl radicals, conducted by Wenqi Chen et al. This study was published in Phys. Chem. Chem. Phys. in 2021.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Organic
Chun-Hong Hu, Yang Li
Summary: A metal-free synthesis of C1-deuterated aldehydes was developed, which utilizes D2O and alpha-oxo carboxylic acids at ambient temperature. This method avoids the use of stoichiometric reductants and oxidants, and can tolerate various functional groups, resulting in high yields and high deuteration levels.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Vasilii Korotenko, Hendrik Zipse
Summary: The stability of various radicals and molecules has been studied using different theoretical methods, and good correlations between theoretical calculations and experimental results have been found. The effects of hydrogen bonding interactions on the stability of oxygen-centered radicals have also been investigated.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2024)
Article
Chemistry, Physical
A. Bouallagui, A. Zanchet, L. Banares, A. Garcia-Vela
Summary: The photodissociation of CH2I radical and CH2I+ cation is investigated using high-level ab initio calculations and spin-orbit effects. Potential-energy curves along the dissociating bond distances are computed for ground and excited electronic states, and possible photodissociation mechanisms are analyzed based on the obtained curves. Differences in fragmentation dynamics between the neutral radical and the cation are observed. The study is relevant to atmospheric chemistry and provides insights into the impact of photodissociation on chemical processes in the atmosphere.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Anita Schneiker, Sandor Gobi, Prasad Ramesh Joshi, Gabor Bazso, Yuan-Pern Lee, Gyorgy Tarczay
Summary: The reaction of H atoms with glycine at 3.1 K in para-H-2 was studied, leading to the formation of C-a-glycyl radical with high selectivity. The radical is sensitive to UV light and can decompose into iminoacetic acid and H atom. This suggests that a-amino acids can be formed from glycine via the C-a-glycyl radical in non-energetic mechanisms in the solid phase of the interstellar medium.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Viki Kumar Prasad, Zhipeng Pei, Simon Edelmann, Alberto Otero-de-la-Roza, Gino A. DiLabio
Summary: Accurately calculating reaction energies and barrier heights is crucial for computational studies of reaction mechanisms and thermochemistry. The BH9 benchmark set, comprising 449 chemical reactions, is the most comprehensive to date and allows for the assessment of computational methods. Despite the penalty associated with using the DLPNO approximation, the reference data obtained are accurate enough to serve as a benchmark for DFT methods.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Management
Jennifer C. Davis, Eric Ping Hung Li, Mary Stewart Butterfield, Gino A. DiLabio, Nithi Sangunthanam, Barbara Marcolin
Summary: This study examines the impact of the shift to remote work environments on tenured and tenure-track faculty in Canada during the COVID-19 pandemic. The findings reveal that female and racialized faculty experienced higher levels of stress, social isolation, and lower well-being. The study calls for organizational change and reform to support these faculty members, with a focus on quantitative metrics, collaborative responses, and amplifying marginalized voices.
GENDER WORK AND ORGANIZATION
(2022)
Correction
Chemistry, Physical
Viki Kumar Prasad, Zhipeng Pei, Simon Edelmann, Alberto Otero-de-la-Roza, Gino A. DiLabio
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
Viki Kumar Prasad, Alberto Otero-de-la-Roza, Gino A. DiLabio
Summary: Density functional theory (DFT) is widely used for modeling noncovalent interactions and thermochemistry. This article presents three new DFT methods that combine appropriate functionals, relatively large basis sets, and atom-centered potentials (ACPs) for improved accuracy and computational efficiency in predicting chemical properties.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
Viki Kumar Prasad, Alberto Otero-de-la-Roza, Gino A. DiLabio
Summary: In this study, a new low-cost quantum mechanical method using atom-centered potentials (ACPs) was developed to model large molecular systems. Machine learning regression technique was utilized to train and validate the ACP-corrected methods. The proposed ACP-corrected methods showed comparable performance to complete basis set density functional theory at a much lower cost, and could improve the description of covalent and noncovalent bond geometries.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Organic
Marco Galeotti, Chiara Trasatti, Sergio Sisti, Michela Salamone, Massimo Bietti
Summary: A kinetic study was conducted to investigate the hydrogen atom transfer (HAT) reactions from nitrogen-containing heterocycles to the cumyloxyl radical. The study revealed that HAT occurs through hyperconjugative overlap between the C-H bonds and the N-C???O π system. The size of the ring and the functional group have significant effects on the reaction rate.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Fengjiao Liu, Siqi Ma, Zeying Lu, Anjanay Nangia, Meng Duan, Yanmin Yu, Guochao Xu, Ye Mei, Massimo Bietti, K. N. Houk
Summary: Density functional theory calculations were employed to study the reactions of radicals with C-H bonds in different environments, and modified Evans-Polanyi treatments were used to analyze the variations in activation barriers, with a focus on polarity and unsaturation effects. The study revealed the quantitative importance of the thermodynamics of reactions and polar effects in determining barriers to reactions involving radicals and C-H bonds.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Marco Galeotti, Laia Vicens, Michela Salamone, Miquel Costas, Massimo Bietti
Summary: The C(sp(3))-H bond oxygenation of cyclopropane-containing mechanistic probes has been studied using hydrogen peroxide catalyzed by manganese complexes. The study showed the presence of both unrearranged and rearranged oxygenation products, suggesting the involvement of cationic intermediates and different pathways. The selective formation of either unrearranged or rearranged product in high yield can be achieved by choosing appropriate catalyst structure and reaction conditions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Polymer Science
Benjamin Godwin, Monir H. Anvari, Tina Olfatbakhsh, Mahshid Mahbod, Abbas S. Milani, Gino A. DiLabio, Jeremy E. Wulff
Summary: Chemical cross-links, both irreversible and reversible, can enhance the mechanical strength and rigidity of polymers. In this study, a ketone-functionalized derivative of polydicyclo-pentadiene is introduced, which forms an unprecedented network of vinyl C-H... O hydrogen bonds within the polymer. The resulting thermoset exhibits significantly improved glass transition temperature, storage modulus, Young's modulus, and compression strength compared to the unfunctionalized polymer.
Article
Chemistry, Organic
Sergio Sisti, Fabio Ioele, Filippo Scarchilli, Marco Galeotti, Gino A. Dilabio, Michela Salamone, Massimo Bietti
Summary: Kinetic and product studies were conducted on the reactions of tert-alkoxyl radicals with secondary and tertiary alkanamides bearing benzylic alpha-C H bonds. The results revealed the exclusive HAT from the benzylic alpha-C H bonds, indicating a lack of benzylic activation and the presence of steric and stereoelectronic effects. In the isoindoline and tetrahydroisoquinoline derivatives, significant increases in kH were observed due to optimal overlap with both the phenyl p-system and the amide p-system or amine nitrogen lone pair, demonstrating the strong contribution of stereoelectronic activation.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Mahsa Nazemi Ashani, Qinan Huang, A. Mackenzie Flowers, Alex Brown, Antoine Aerts, Alberto Otero-de-la-Roza, Gino A. Dilabio
Summary: The β-density functional theory (β-DFT) approach based on atom-centered potentials (ACPs) is shown to be a computationally inexpensive and accurate method for representing potential energy surfaces (PESs) and calculating vibrational frequencies for HONO and HFCO molecules. The ACP-corrected PESs produce small mean absolute errors and compared favorably to the results obtained with higher level of theory. This approach shows promise for representing accurate molecular PESs and calculating molecular properties.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Multidisciplinary
Marco Galeotti, Woojin Lee, Sergio Sisti, Martina Casciotti, Michela Salamone, K. N. Houk, Massimo Bietti
Summary: A product and DFT computational study was conducted on the reactions of 3-ethyl-3-(trifluoromethyl)dioxirane (ETFDO) with bicyclic and spirocyclic hydrocarbons bearing cyclopropyl groups. The reactions exhibited good site-selectivities and diastereoselectivities, which were supported by calculated activation free energies. The computational results showed that hyperconjugative interactions between the cyclopropane C-C bonding orbitals and the sigma* orbitals of the C-H bonds activated these bonds towards hydrogen atom transfer to ETFDO.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Sergio Sisti, Marco Galeotti, Filippo Scarchilli, Michela Salamone, Miquel Costas, Massimo Bietti
Summary: A detailed study on C(sp(3))-H bond oxygenation reactions catalyzed by [Mn(OTf)(2)((TIPS)mcp)] complex was conducted, showing that the introduction of electron-withdrawing functional groups in different solvents significantly increased site-selectivity and product yield. The study also achieved selective control over multiple methylenic sites.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Andrea Palone, Guillem Casadevall, Sergi Ruiz-Barragan, Arnau Call, Siilvia Osuna, Massimo Bietti, Miquel Costas
Summary: This study describes a catalytic enantioselective hydroxylation method of tertiary C-H bonds in cyclohexane scaffolds using an evolved manganese catalyst and H2O2. The catalytic system provides structural complementarity to the substrate similarly to lock-and-key recognition in enzymatic active sites. Theoretical calculations reveal that enantioselectivity is determined by the precise fitting of the substrate scaffold into the catalytic site through a network of complementary weak non-covalent interactions. Stereoretentive C(sp(3))-H hydroxylation results in the generation of multiple stereogenic centers in a single step, which can be orthogonally manipulated to obtain a variety of chiral scaffolds from a single precursor molecule.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Review
Chemistry, Multidisciplinary
Marco Galeotti, Michela Salamone, Massimo Bietti
Summary: Direct functionalization of C(sp(3))-H bonds is a key focus in developing new synthetic methods. Among intermolecular C-H bond functionalization strategies, hydrogen atom transfer (HAT) methods using radical or radical-like reagents have gained increasing attention due to their ability to introduce a variety of atoms and groups in mild conditions. Selectivity control over aliphatic C-H bonds is crucial and factors influencing it have been discussed. This review article provides a detailed description of HAT reagents, associated mechanistic features, and selectivity patterns observed in the functionalization of increasingly complex substrates, based on an analysis of recent literature.
CHEMICAL SOCIETY REVIEWS
(2022)
