Article
Chemistry, Multidisciplinary
Qingyang Wang, Richard A. Manzano, Hendrik Tinnermann, Simon Sung, Baptiste Leforestier, Tobias Kraemer, Rowan D. Young
Summary: The use of PCcarbeneP pincer ligands allows for metal-ligand cooperative reactivity and support for a variety of iron oxidation states, making it potentially useful in catalytic applications.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Inorganic & Nuclear
Yogita Arya, Sudip Kumar Bera, Jose Luis Priego, Reyes Jimenez-Aparicio, Goutam Kumar Lahiri
Summary: The present work successfully synthesized diruthenium and monoruthenium complexes and characterized their structures. The study showed that these complexes exhibited multiple redox processes and demonstrated the involvement of bidirectional redox non-innocent feature.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Multidisciplinary
Brandon Johnston, Daniel M. Loh, Daniel G. Nocera
Summary: This study reveals a metal-free electrochemical reaction method for the selective cross-coupling of 1,4-dicyanobenzene and alkyl bromides. This method avoids the self-coupling reaction of alkyl bromides and is compatible with oxidatively sensitive and acidic functional groups, providing a promising strategy for C-C bond construction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Chemistry, Multidisciplinary
Rajendra S. Ghadwal
Summary: This review article aims to highlight recent advances in accessing stable iMICs, quantifying their properties, and exploring their applications in synthesis and catalysis. The synthetic viability and use of vicinal C4,C5-anionic dicarbenes (ADCs) based on a 1,3-imidazole framework are also presented. iMICs and ADCs have the potential to push the limit of classical NHCs by enabling access to conceptually new main-group heterocycles, radicals, molecular catalysts, ligand sets, and more.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Jingjing Xie, Pan Xu, Yiling Zhu, Jingyi Wang, Wan-Chen Cindy Lee, X. Peter Zhang
Summary: By optimizing the Co(II)-based metalloradical catalyst with a chiral ligand, a new catalytic radical process has been developed for asymmetric 1,4-C-H alkylation of diazoketones, leading to the construction of chiral cyclobutanone structures with high stereoselectivity. This process offers a mild and efficient method for the synthesis of enantioenriched cyclobutanones with potential applications in stereoselective organic synthesis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Inorganic & Nuclear
Gayathri B. Gange, Amanda L. Humphries, Mark D. Smith, Dmitry V. Peryshkov
Summary: In this study, we report the reactivity of carboranyl diphosphine with terminal alkynes, resulting in the formation of boron-containing phosphacycles. The reaction combines the activation of electron-deficient alkynes by phosphine groups and the redox behavior of carborane clusters, leading to the formation of a fused product of alkenylphosphonium cycle and reduced carborane cluster.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Debabrata Dhara, Felipe Fantuzzi, Marcel Haerterich, Rian D. Dewhurst, Ivo Krummenacher, Merle Arrowsmith, Conor Pranckevicius, Holger Braunschweig
Summary: This study reports the reduction of bulky ferrocenyl-based NHC-stabilised aluminium(iii) diiodide in different hydrocarbon solvents, with different outcomes observed in hexane and aromatic solvents. Reduction in hexane led to C-H activation, while reduction in aromatic solvents resulted in unknown Birch-type reductions of solvent molecules.
Article
Chemistry, Multidisciplinary
Vikramjeet Singh, Abhishek Kundu, Kirti Singh, Debashis Adhikari
Summary: Formazan ligands have long been investigated as redox-noninnocent backbones, but their catalytic efficiency governed by redox noninnocence remains elusive. In this study, we report an iron-formazanate molecule that can efficiently prepare alpha-keto amides through a tightly regulated reductive cleavage of the substrate molecule by the electron donation from the formazanate, in a reversible manner.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Abdollah Neshat, Rahimeh Khezri, Mohammad Reza Yousefshahi, Mohammad Gholinejad, Fahimeh Varmaghani
Summary: The synthesis and characterization of Nickel(II) complexes with novel pincer-type N-heterocyclic carbene complexes were investigated. The complexes showed high activity as catalysts for the coupling reactions of aryl and alkyl halides. By adjusting the steric hindrance of the ligand, better catalytic performance could be achieved. Under the experimental conditions, a catalyst loading as low as 5 mol% could yield high-productivity products.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Review
Chemistry, Multidisciplinary
Yan-Nan Zheng, Hongxing Zheng, Ting Li, Wen-Ting Wei
Summary: C-N bonds are widely present in organic materials, natural products, pharmaceutical compounds, and agricultural chemicals. The development of greener and more convenient ways to form C-N bonds, particularly in late-stage synthesis, has become a hot research topic in synthetic chemistry. Copper-catalyzed radical reactions involving N-centered radicals are considered as a sustainable and promising approach for building C-N bonds.
Article
Chemistry, Multidisciplinary
Wowa Stroek, Martin Keilwerth, Daniel M. Pividori, Karsten Meyer, Martin Albrecht
Summary: The synthesis of N-heterocycles is crucial for the pharmaceutical industry, and a greener alternative using direct intramolecular C-H amination has been explored. A new iron-based complex catalyst was developed in this study, which can catalyze reactions without the need for protecting groups and achieved a significantly higher turnover number compared to other reported systems.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Kun-You Chung, Zachariah A. Page
Summary: This article introduces a new type of visible light photoinitiator that can polymerize acrylic-based resins to maximum conversion using low energy green light. The photoinitiator has the ability to access long-lived triplet excited states, which is promising for next generation manufacturing and biomedical applications.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Marina Toplak, Raspudin Saleem-Batcha, Joern Piel, Robin Teufel
Summary: The article presents a spioketal synthase that is involved in the biosynthesis of stable chroman spiroketals, showcasing its multifunctional role in controlling the redox state of the substrate and cleavage of carbon-carbon bonds.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
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
Ramapada Dolai, Rahul Kumar, Benedict J. Elvers, Pradeep Kumar Pal, Benson Joseph, Rina Sikari, Mithilesh Kumar Nayak, Avijit Maiti, Tejender Singh, Nicolas Chrysochos, Arumugam Jayaraman, Ivo Krummenacher, Jagannath Mondal, U. Deva Priyakumar, Holger Braunschweig, Cem B. Yildiz, Carola Schulzke, Anukul Jana
Summary: A new type of carbodicarbene (CDC) with two different classes of carbenes has been reported, which shows promising potential as organic electron donors and n-dopants. These compounds exhibit notable redox properties and can form carbon-carbon sigma bonds through reactions with [NO][SbF6].
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Organic
Flip Holtrop, Christoph Helling, Martin Lutz, Nicolaas P. van Leest, Bas de Bruin, J. Chris Slootweg
Summary: We present a combined theoretical and experimental investigation on the potential isolation of an encounter complex enabled by enhancement of London dispersion forces between a sterically encumbered Lewis acid and base pair. The study involved the bulky triarylamine N(3,5-tBu(2)C(6)H(3))(3) and the novel triarylborane B(3,5-tBu(2)C(6)H(3))(3), leading to the isolation of a 1:1 co-crystal of both FLP components.
Article
Chemistry, Multidisciplinary
Minghui Zhou, Simon Mathew, Bas de Bruin
Summary: A new T-type molecular photoswitch based on the reversible cyclization of 1H-2-benzo[c]oxocins has been developed. The switching mechanism involves light-triggered ring contraction and thermal ring-opening processes. The new molecular-switching platform exhibits independence from solvent polarity and is suitable for biological applications. The reactions proceed with good efficiency and can be easily adjusted via structural functionalization.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Pan Xu, Jingjing Xie, Duo-Sheng Wang, X. Peter Zhang
Summary: Co(II)-based metalloradical catalysis enables the chemoselective intermolecular amination of allylic C-H bonds and achieves remarkable convergence of regioselectivity, diastereoselectivity, and enantioselectivity. The use of modularly designed D-2-symmetric chiral amidoporphyrins as supporting ligands creates a tunable pocket-like environment. This reaction offers a direct route to synthesize valuable chiral alpha-tertiary amines from an isomeric mixture of alkenes.
Article
Chemistry, Multidisciplinary
Soumyadeep Chakrabortty, Katharina Konieczny, Felix J. de Zwart, Eduard. O. Bobylev, Eszter Barath, Sergey Tin, Bernd H. Mueller, Joost N. H. Reek, Bas de Bruin, Johannes G. de Vries
Summary: Researchers achieved enantioselective hydrogenation of cyclic enamides using an earth-abundant cobalt-bisphosphine catalyst. The catalytic system, CoCl2/(S,S)-Ph-BPE, reduced trisubstituted carbocyclic enamides to saturated amides with high activity and excellent enantioselectivity (up to 99%). The methodology can be extended to the synthesis of chiral amines by base hydrolysis of the hydrogenation products. Preliminary mechanistic investigations suggested a sigma-bond-metathesis pathway for the hydrogenation of the carbon-carbon double bond, involving a high spin cobalt (II) species.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Catriona C. James, Petrus C. M. Laan, Bas de Bruin, Joost N. H. Reek
Summary: Olefin metathesis catalysts, such as AquaMet, are susceptible to decomposition under biologically relevant conditions. Current stabilizing strategies have limited applicability under these conditions. Encapsulation of AquaMet within a supramolecular metallocage, with nitrate counterions, enhances the catalyst activity. Replacement of AquaMet's chloride ligands with nitrates through simple anion-exchange leads to higher yields of ring-closed product under aqueous and biological conditions. This kinetic protection strategy of transition metal catalysts may find applications in other in vivo catalytic reactions.
Article
Chemistry, Multidisciplinary
Wan-Chen Cindy Lee, Jingyi Wang, Yiling Zhu, X. Peter Zhang
Summary: Asymmetric radical bicyclization processes using metalloradical catalysis have been developed to construct chiral chromanones and chromanes with fused cyclopropanes. Through optimization of the chiral amidoporphyrin ligand platform, a Co(II)-metalloradical system can activate different alkene functionalities under mild conditions for effective radical bicyclization, delivering desired products with high yields and excellent control of stereoselectivities. Computational and experimental studies reveal the stepwise radical mechanisms involved in the Co(II)-catalyzed bicyclization processes.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Roel F. J. Epping, David Vesseur, Minghui Zhou, Bas de Bruin
Summary: Discovered in the 1970s as organometallic curiosities, carbene radicals have become essential in modern homogeneous catalysis. These radicals exhibit nucleophilic reactivity different from electrophilic Fischer carbenes. The successful catalytic application of carbene radicals has led to the synthesis of diverse carbon and heterocyclic compounds. This Perspective provides an overview of the coordination chemistry, reactivity, and catalytic application of carbene radicals using transition metal complexes and catalysts since 2011.
Article
Chemistry, Physical
Petrus C. M. Laan, Felix J. de Zwart, Emma M. Wilson, Alessandro Troglia, Olivier C. M. Lugier, Norbert J. Geels, Roland Bliem, Joost N. H. Reek, Bas de Bruin, Gadi Rothenberg, Ning Yan
Summary: In this study, the reactivity and selectivity of two forms of NiOOH (beta-NiOOH and gamma-NiOOH) were examined using three typical alcohols as model reactions. The results showed that the solvent had an effect on the reaction rate of beta-NiOOH but not on its selectivity. Moreover, high concentrations of OH(-) in aqueous solvent promoted the conversion of benzyl alcohol to benzoic acid. The mechanism of oxidative dehydrogenation of benzyl alcohol to benzaldehyde was also elucidated. This work highlights the unique oxidative and catalytic properties of NiOOH in alcohol oxidation reactions and contributes to the mechanistic understanding of electrochemical alcohol conversion using NiOOH-based electrodes.
Article
Chemistry, Multidisciplinary
Jasper Biemolt, Eva J. Meeus, Felix J. de Zwart, Jeen de Graaf, Petrus C. M. Laan, Bas de Bruin, Thomas Burdyny, Gadi Rothenberg, Ning Yan
Summary: Immobilizing molecular catalysts on electrodes is crucial for electrochemical applications. The study demonstrates a bottom-up approach for constructing a conjugated C-C bond between the Vulcan carbon electrode and an organometallic catalyst without introducing any foreign elements. The synthesized catalyst exhibits high activity and selectivity for the oxygen reduction reaction compared to the homogeneous counterpart, making it a promising candidate for electrochemical applications.
Article
Chemistry, Multidisciplinary
Subrata Das, Andreas W. Ehlers, Sima Patra, Bas de Bruin, Buddhadeb Chattopadhyay
Summary: A concept for intermolecular C-N cross-coupling amination has been discovered using tetrazoles and aromatic and aliphatic azides with boronic acids under iron-catalyzed conditions. The reaction follows an unprecedented metalloradical activation mechanism, different from traditional metal-catalyzed C-N cross-coupling reactions. The wide scope of this reaction has been demonstrated by employing various tetrazoles, azides, and boronic acids. Moreover, the reaction has shown potential for applications in medicinal chemistry, drug discovery, and pharmaceutical industries, as demonstrated by late-stage aminations and synthesis of a drug candidate.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Jianghua Liu, Eduard O. Bobylev, Bas de Bruin, Joost N. H. Reek
Summary: This article reports on a gold catalyst based on azobenzene-bearing N-heterocyclic carbene, whose reactivity in a cyclization reaction is dependent on the isomeric state of the azobenzene. The configurations of the catalyst can be reversibly switched by light and remain stable during the reaction, effectively leading to a switchable catalyst system.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Eduard O. Bobylev, Renzo A. Knol, Simon Mathew, I. I. I. David A. Poole, Ioli Kotsogianni, Nathaniel I. Martin, Bas de Bruin, Alexander Kros, Joost N. H. Reek
Summary: There is a growing interest in using metal-organic cages (MOCs) in the field of biomedicine due to their unique distribution in organisms and novel cytotoxicity mechanisms. However, the stability of many MOCs under in vivo conditions hinders their study in living cells. In this study, the toxicity and photophysical properties of stable rhodamine-functionalized platinum-based Pt2L4 nanospheres and their building blocks are investigated in vitro and in vivo. The results show that the Pt2L4 nanospheres exhibit reduced cytotoxicity and altered biodistribution compared to the building blocks in zebrafish and human cancer cell lines. These findings provide a basis for the application of MOCs in cancer therapy.
Article
Chemistry, Physical
Martijn J. Mekkering, Jasper Biemolt, Jeen de Graaf, Yi-An Lin, Nicolaas P. van Leest, Alessandro Troglia, Roland Bliem, Bas de Bruin, Gadi Rothenberg, Ning Yan
Summary: This study demonstrates that the agglomeration of isolated atom sites can be prevented by dissolution/exsolution of metal atoms into/from the support in the case of Rh/Al2O3 single-atom catalysts. A series of catalysts are designed, synthesised and characterised to study the impact of exsolution in the dry reforming of methane. The catalysts' performance improves with increasing reaction time due to the migration of rhodium atoms from the subsurface to the surface. The main factor affecting catalyst performance is atom migration, despite the changes in rhodium oxidation state during catalysis. The implications of these results for real-life catalyst preparation are discussed.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Eva J. Meeus, Nico V. Igareta, Iori Morita, Thomas R. Ward, Bas de Bruin, Joost N. H. Reek
Summary: This study demonstrates that the incorporation of a biotinylated Co(TAML) cofactor within streptavidin enhances the activity and enantioselectivity of asymmetric radical-type oxygen atom transfer catalysis.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Eduard. O. Bobylev, Leonardo Passerini, Felix J. de Zwart, David A. Poole, Simon Mathew, Martina Huber, Bas de Bruin, Joost N. H. Reek
Summary: In this study, a post-assembly modification approach is described to selectively coordinate transition metals in Pd12L24 cuboctahedra. The method involves the preparation of Pd12L24 nanospheres with protonated nitrogen donor ligands that are covalently linked at the interior. Selective formation of different coordination forms of the transition metals is achieved by using different nitrogen donor ligands. Experimental and computational investigations support the presence of complexes at precise locations in the nanospheres.