Article
Chemistry, Physical
Helgi Freyr Jonsson, Daniel Sethio, Julian Wolf, Stefan M. Huber, Anne Fiksdahl, Mate Erdelyi
Summary: Gold catalysis provides innovative organic transformations with high chemoselectivity under mild conditions. A silver-free route utilizing halogen bonding is presented for gold activation, reducing metal waste and enabling large-scale generation of complex molecules. The recyclability of gold is of supreme importance.
Article
Crystallography
Luka Fotovic, Vladimir Stilinovic
Summary: The study showed that N-ethylated halogenopyridinium cations form shorter halogen bonds with iodide anions, and two novel asymmetric monocations were obtained during the synthesis process.
Article
Chemistry, Physical
Vali Alizadeh, Ghodrat Mahmoudi, Marina A. Vinokurova, Kuzma M. Pokazeev, Kseniia A. Alekseeva, Barbara Miroslaw, Ali Akbar Khandar, Antonio Frontera, Damir A. Safin
Summary: In this work, the crystal structures of three heteroleptic coordination compounds were reported, showing specific coordination characteristics of the ligand molecule HL. The interactions between metal and halogen play a crucial role in the formation of multi-dimensional structures.
JOURNAL OF MOLECULAR STRUCTURE
(2022)
Article
Chemistry, Multidisciplinary
Colleen P. Chernowsky, Alyah F. Chmiel, Zachary K. Wickens
Summary: Electrochemical stimulation can induce new photocatalytic activity in a range of structurally diverse conventional photocatalysts, promoting the reductive cleavage of strong C(sp(2))-N and C(sp(2))-O bonds. This method, known for its deep reducing ability, safety, and mild conditions, has shown synthetic utility. The improved activity of this new system is attributed to an enhanced catalyst stability, as revealed by electrochemical current measurements.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Ben Niu, Krishnakumar Sachidanandan, Bryan G. Blackburn, Maria Victoria Cooke, Sebastien Laulhe
Summary: Here, we report the first polyfluoroarylation of unactivated alkyl halides via a halogen atom transfer process. This method shows good yields in converting primary, secondary, and tertiary alkyl halides into the respective polyfluoroaryl compounds, including derivatives of complex bioactive molecules.
Article
Chemistry, Multidisciplinary
Ke-yi Deng, Zhi-wei Wang, Zhen-zhen Xie, Jun-tao He, Jian-ping Guan, Kai Chen, Hao-yue Xiang, Hua Yang
Summary: The development of a new catalytic and straightforward strategy for constructing C-N bonds is important in synthetic chemistry. In this study, we present a photocatalysed protocol for direct C-H amidation of indoles using a rationally designed tert-butyl alkyl((perfluoropyridin-4-yl)oxy)carbamate. A range of biologically significant aminoindoles were synthesized under mild conditions with excellent regioselectivity and broad substrate scope.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Andrea Daolio, Andrea Pizzi, Susanta K. Nayak, Justyna Dominikowska, Giancarlo Terraneo, Pierangelo Metrangolo, Giuseppe Resnati
Summary: Due to its high electron density, fluoride anions are the most effective halogen bond acceptors among the halides. However, under common experimental conditions, fluoride ions rarely act as acceptors, possibly due to their hydrated form. Here, we report that under specific crystallization conditions, a hydrogen bond-free fluoride ion acting as an electron density donor can be obtained, and the resulting halogen bonds play a significant role in the observed crystal packings. Computational studies confirm the strength of these halogen bonds compared to similar interactions involving other halides.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Vihanga K. Munasinghe, Jessica Pancholi, Dilhan Manawadu, Zongyao Zhang, Paul D. Beer
Summary: This study investigated the ability of a family of novel halogen bonding and hydrogen bonding heteroditopic rotaxane host systems to recognize lithium halide ion-pairs. The results showed that the rotaxane hosts exhibited selectivity for LiBr over LiI, and the strength of halide binding increased with the number of halogen bond donors integrated into the interlocked cavity. DFT calculations confirmed these findings, revealing the mode of LiX ion-pair binding. The cooperative, heteroditopic, rotaxane axle-macrocycle component mechanical bond effect was identified as an efficient strategy for ion-pair recognition in general.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Multidisciplinary Sciences
Xiang Sun, Ke Zheng
Summary: An effective electrooxidation strategy for generating alkyl radicals from unactivated alkyl iodides via an electrochemical halogen-atom transfer process under mild conditions is reported here.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Paloma Mingueza-Verdejo, Juan Carlos Hernandez-Garrido, Alejandro Vidal-Moya, Judit Oliver-Meseguer, Antonio Leyva-Perez
Summary: Simple aluminosilicates, such as NaX and NaY zeolites, can catalyze the selective halogen exchange reaction between different alkyl organohalides without any additives or solvents. By heating at 130 degrees C with a small amount of solid catalyst, new organohalides are produced in good yields, tolerating different functional groups. Mechanistic studies reveal the importance of zeolite oxygen atoms and countercations in facilitating the reaction.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Jun Zhu, Yibin Xue, Rui Zhang, Benjamin L. Ratchford, Guangbin Dong
Summary: This article describes a catalytic method for activating unstrained and nonpolar C-C bonds, using removable directing groups to aid in the hydrogenolysis of unstrained C(aryl)-C(alkyl) bonds in 2,2'-methylenediphenols. The method yields high amounts of monophenol products and is tolerant of a wide range of functional groups. Additionally, the reaction is scalable and the catalyst loading can be reduced to as low as 0.5 mol %. The method also proves effective in cleaving C(aryl)-C(alkyl) linkages in both phenolic resins and commercial novolacs resins. Experimental and computational mechanistic studies show that the transformation occurs through a directed C(aryl)-C(alkyl) oxidative addition pathway, with C-H activation being a competitive but reversible off-cycle reaction.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Tadashi Kanbara, Mizuki Arase, Miyu Tanaka, Airi Yamaguchi, Koto Tagami, Tomoko Yajima
Summary: In this study, synthesis methods for fluorine-containing polymers were developed using photoirradiation halogen bonding. Sequential polymerization resulted in fluoroalkyl-alkyl-alternating polymers, while chain polymerization produced polymers with perfluoroalkyl terminals. Block polymers were also synthesized through successive chain polymerization.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Takumi Nakajima, Ken Takano, Hiromu Maeda, Yohei Ogiwara, Norio Sakai
Summary: The study shows that disilathiane is effective in mediating the synthesis of alkyl aryl sulfides, promoting cleavage of disulfides to generate thiosilane. Diselenides can also be used in this transformation to produce corresponding selenides.
CHEMISTRY-AN ASIAN JOURNAL
(2021)
Review
Chemistry, Physical
Krishnakumar Sachidanandan, Ben Niu, Sebastien Laulhe
Summary: The merging of photocatalysis with halogen-atom transfer processes provides a versatile tool for generating carbon-centered radicals in organic synthesis. Three major pathways for achieving XAT in synthetic applications are categorized as heteroatom-based, metal-based, and carbon-based activators, with a-aminoalkyl radicals taking the center stage. The simplicity and broad applications of a-aminoalkyl radicals as XAT reagents make them an attractive alternative to heteroatom/metal-based radicals.
Article
Chemistry, Organic
Liang-Hua Zou, Biao Liu, Cheng Wang, Zeyu Shao, Junqi Zhou, Andong Shao, Jian Wen
Summary: An efficient and green method for synthesizing various alkyl amines through the cleavage of vinylsulfonium salts' C(sp(3))-S bond has been developed. This reaction can be conducted under air atmosphere and shows a broad range of applicability with N-nucleophiles. Additionally, N-vinylazoles can be obtained with moderate to good yields through the reaction of vinylsulfonium salts with N-containing heterocycles in the presence of a base at room temperature.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Organic
Yichao Zhao, James Theodore Merrett, Jianwen Jin, Li-Juan Yu, Michelle Louise Coote, Philip Wai Hong Chan
Summary: This study describes a synthetic method for the alpha-alkynylation of tertiary alpha-silylamines by 1-iodoalkynes, mediated by [Au-2(mu-dppm)(2)]Cl-2 and UVA LED light (lambda = 365 nm). The reaction showed excellent functional group tolerance and could be applied to a wide range of coupling partners, as well as various bioactive molecules and natural products. Experimental and computational studies suggested an oxidative quench pathway and the involvement of a dimeric metal complex in mediating the cross-coupling of two radical species, which is unprecedented in photoredox gold catalysis.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Analytical
Mattia Belotti, Mohsen M. T. El-Tahawy, Marco Garavelli, Michelle L. Coote, K. Swaminathan Iyer, Simone Ciampi
Summary: The study develops a direct, spatiotemporally resolved optical tracking method to detect and resolve convective disturbances in electrochemical reactivity. It is found that parasitic gas evolving reactions lead to overestimates of macroscopic diffusion coefficients by 10 times. A hypothesis is proposed linking large barriers to inner-sphere redox reactions to the formation of cation-rich overscreening and crowding double layer structures in imidazolium-based ionic liquids.
ANALYTICAL CHEMISTRY
(2023)
Article
Chemistry, Physical
Kaycee Low, Michelle L. Coote, Ekaterina I. Izgorodina
Summary: This work extends the electron deformation density-based descriptor to predict three-body interactions in trimers. The resulting Gaussian process regression (GPR) model shows good prediction accuracy on the 3B69 and S22-3 trimer data sets. A hybrid kernel function is introduced to predict the total trimer interaction energy and three-body contribution using the same descriptor. A new data set based on protein-ligand crystal structures is introduced, providing benchmark calculations for larger molecular interactions. Compared to DFT- and wavefunction-based methods, our model reduces the required SCF calculations and shows faster predictions.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Multidisciplinary
Shangxu Jiang, Yihui Xie, Yuan Xie, Li-Juan Yu, Xiaoqing Yan, Fu-Gang Zhao, Chanaka J. Mudugamuwa, Michelle L. Coote, Zhongfan Jia, Kai Zhang
Summary: This study investigates the (electro)chemical behavior of TEMPO in organic and aqueous Lewis acid electrolytes and unveils its reversible disproportionation process in aqueous media. Based on these findings, a radical polymer aqueous AIBs is designed and demonstrates promising stability and performance.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Jasmine M. M. Pople, Thomas P. P. Nicholls, Le Nhan Pham, Witold M. M. Bloch, Lynn S. S. Lisboa, Michael V. V. Perkins, Christopher T. T. Gibson, Michelle L. L. Coote, Zhongfan Jia, Justin M. M. Chalker
Summary: In this study, a new method for the synthesis of high sulfur content polymers was developed using electrochemically initiated ring-opening polymerization. This method offers improved safety and control of structure by eliminating the need for hazardous chemical initiators. The resulting polymer exhibits good solubility and processability. Thermal depolymerization of the polymer allows for its recycling back to the cyclic trisulfide monomer. The polymer also demonstrates effective gold sorption, suggesting potential applications in mining and electronic waste recycling.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Samuel J. Tonkin, Le Nhan Pham, Jason R. Gascooke, Martin R. Johnston, Michelle L. Coote, Christopher T. Gibson, Justin M. Chalker
Summary: With increasing applications of infrared imaging, there is a demand for low-cost alternatives to traditional infrared optics materials. Sulfur-rich copolymers show promise due to their cost-effectiveness and high refractive index. This study reports on the copolymerization of cyclopentadiene with sulfur, resulting in a plastic with the highest long-wave infrared transparency observed for this class of materials. The copolymer can be used in various lens architectures and as an infrared-transparent blind for thermal imaging equipment and clandestine surveillance, suggesting broader use of sulfur copolymers in infrared optics.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Chemistry, Physical
Lorenzo Franco, Abdirisak Ahmed Isse, Antonio Barbon, Lina Altomare, Viivi Hypponen, Jessica Rosa, Venla Olsson, Mikko Kettunen, Lucio Melone
Summary: This paper presents the synthesis, characterization, and in vivo application of water-soluble supramolecular contrast agents for MRI. The contrast agents were obtained from β-cyclodextrin functionalized with different nitroxide radicals. The experiments showed that the contrast agents had improved stability in vitro and in vivo, and were non-cytotoxic at low concentrations. The MRI experiments on glioma-bearing rats demonstrated a good lowering of T-1 relaxation in the tumor, indicating the potential of these contrast agents for improved tumor imaging.
Article
Chemistry, Multidisciplinary
Chenghui Zhu, Le Nhan Pham, Xu Yuan, Haoran Ouyang, Michelle L. Coote, Xinxing Zhang
Summary: The use of external electric fields as green and efficient catalysts in synthetic chemistry has gained significant attention. This study takes advantage of the spontaneous high electric field at the air-water interface of sprayed water microdroplets to facilitate ultrafast reactions in several halogen bond systems. The results suggest that microdroplet chemistry holds great potential for reactions facilitated by high electric fields and offers an alternative solution to the scalability problem.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Francesca Lorandi, Marco Fantin, Hossein Jafari, Adam Gorczynski, Grzegorz Szczepaniak, Sajjad Dadashi-Silab, Abdirisak A. Isse, Krzysztof Matyjaszewski
Summary: Linear free energy relationships (LFERs) were used to establish the reductive cleavage of the C(sp(3))-X bond in alkyl halides (RX) by Cu complexes. The activation rate constant, k(act), for 107 Cu complex/RX couples in 5 different solvents were effectively interpolated by an equation. The set of descriptors determined the fundamental properties of Cu complexes and RX, which need to be considered when designing atom transfer radical reactions. A multivariate linear regression (MLR) approach was adopted to develop an objective model that surpassed the predictive capability of the LFER equation.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Zhipeng Pei, Nicholas L. Magann, Madison J. Sowden, Rhys B. Murphy, Michael G. Gardiner, Michael S. Sherburn, Michelle L. Coote
Summary: The ground-state structure of p-QDM is typically represented as a closed shell cyclic compound, but it has been proposed to have an open shell aromatic singlet diradical form as well. Calculations reveal a 29% open-shell contribution to the structure, and dimerization occurs through a low barrier singlet diradical pathway. In contrast, TCNQ, despite having similar diradical character, shows no dimerization or reactivity with TEMPO.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Review
Polymer Science
Gerard Audran, Elena G. Bagryanskaya, Raphael Bikanga, Michelle L. Coote, Olga Guselnikova, Chelsey L. Hammill, Sylvain R. A. Marque, Philippe Mellet, Pavel S. Postnikov
Summary: Dynamic Covalent Bonds (DCB) are labile covalent bonds that play a significant role in the design of next generation materials. Alkoxyamines exhibit a unique C-O DCB that can be cleaved under various stimuli, and the cleavage kinetics and thermodynamics can be controlled by modifying the structure of the molecules. Despite being easily incorporated into polymers, the dynamic covalent properties of alkoxyamines have not been fully utilized in materials sciences.
PROGRESS IN POLYMER SCIENCE
(2023)
Review
Chemistry, Physical
Marco Fantin, Abdirisak Ahmed Isse
Summary: This review explores the application of atom transfer radical polymerization (ATRP) in modifying electrode surfaces and creating functional materials for electrochemical purposes. It emphasizes the advantages of using ATRP-based polymers for the fabrication of supercapacitors, electrocatalysts, and ultra-sensitive electrochemical sensors.
CURRENT OPINION IN ELECTROCHEMISTRY
(2023)
Article
Chemistry, Organic
Ting-Ting Yuan, Jing Chen, Le Nhan Pham, Sayan Paul, Lorenzo V. White, Jialong Li, Ping Lan, Michelle L. Coote, Martin G. Banwell, Yu-Tao He
Summary: Efficient and versatile syntheses of methylene-bridged bis-heterocycles are described, which involve a visible light-mediated radical-relay sequence. This process begins with the homolysis of O-H bonds contained within & beta;,& gamma;-unsaturated oximes, generating oxygen-centred radicals that add to the tethered olefin. The resulting carbon-centered radical is then trapped by an added N-heteroarenium salt. These findings provide new insights into alkoxy radical-mediated transformations and access to new molecular scaffolds with potential applications in various settings.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Inorganic & Nuclear
Michael A. Stevens, Li Feng Lim, Le Nhan Pham, Nicholas Cox, Michelle L. Coote, Annie L. Colebatch
Summary: The reaction between the ligand 2,7-bis(6-methyl-2-pyridyl)-1,8-naphthyridine (MeL) and the MnI and MnII precursors resulted in the formation of monometallic and bimetallic manganese complexes. The EPR results showed the magnetic properties of one of the complexes.
DALTON TRANSACTIONS
(2023)
Article
Polymer Science
Gianluca Gazzola, Andrea Antonello, Abdirisak A. Isse, Marco Fantin
Summary: An electrochemically controlled atom transfer radical polymerization (eATRP) was successfully performed using a minimal amount of FeBr3 catalyst in a nonpolar solvent. The use of electrocatalytic methods in a highly nonpolar polymerization medium allowed for precise control over the polymerization process. Additionally, the setup of an undivided cell with simple iron wire electrodes significantly reduced electrical resistance and enabled the production of polymers with low dispersity. Examination of kinetic and thermodynamic aspects indicated that the high ATRP equilibrium constant of Fe catalysts in nonpolar environments facilitated ppm-level catalysis.