Review
Chemistry, Multidisciplinary
Abing Duan, Fengjiao Xiao, Yu Lan, Linbin Niu
Summary: This review summarizes the representative advancements in theoretical studies on transition-metal-catalyzed reductive coupling reactions, focusing on the mechanisms of key steps and the activation modes of electrophiles, as well as the generation of selectivity. The mechanism of the reduction of high-oxidation-state catalysts and the construction of new chemical bonds are also discussed.
CHEMICAL SOCIETY REVIEWS
(2022)
Review
Chemistry, Inorganic & Nuclear
Zhilong Li, Chengyang Li, Yu Ding, Haohua Huo
Summary: The merger of nickel catalysis and photocatalysis has provided a transformative platform for the rapid assembly of molecular complexity. However, the development of enantioselective transformations in nickel photoredox catalysis remains challenging but holds great promise.
COORDINATION CHEMISTRY REVIEWS
(2022)
Article
Chemistry, Inorganic & Nuclear
Jiarui Chang, Fei Fang, Chenhao Tu, Jie Zhang, Nana Ma, Xuenian Chen
Summary: A series of bis(phosphinite) pincer ligated nickel complexes were used to catalyse the hydrosilylation of aldehydes, among which complexes 1 and 2 showed higher activity compared to complexes 3, 4, and 5. The expected alcohols were obtained in good to excellent yields.
INORGANICA CHIMICA ACTA
(2021)
Article
Chemistry, Applied
Beatriz A. L. da Silva, Beatriz F. dos Santos, Nelson Luis C. Domingues
Summary: This article reports a light-assisted C-S cross-coupling reaction between thiols and 5-chlorobenzofurazan. A new nickel catalyst was used to synthesize 11 unpublished compounds, and the mechanism and influence of light irradiation on this reaction were evaluated. The results showed that the excited state of the nickel catalyst promoted by blue light irradiation undergoes reductive elimination with the C-S coupling product. This method tolerates various functional groups within the thiol, achieving a yield of over 99% after 6 hours of reaction.
APPLIED ORGANOMETALLIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Jing Wen, Zhewei Li, Yanhui Tang, Min Pu, Ming Lei
Summary: In this study, density functional theory (DFT) was used to investigate the mechanism of amide formation from aryl epoxides and amines catalyzed by ruthenium pincer complexes. The results showed that bipyridine-based Ru-PNN A1 pincer complexes could be potential highly catalytic species for the synthesis of amides, and the rate-determining step is the amine-assisted hydrogen elimination. This study provides new insights and theoretical guidance for the design of novel transition-metal catalysts for amide synthesis.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Yangzhong Qin, Rui Sun, Nikolas P. Gianoulis, Daniel G. Nocera
Summary: The researchers conducted a comprehensive mechanistic study of photoredox nickel-catalyzed C-S cross-coupling, revealing a self-sustained productive Ni(I/III) cycle, the role of in situ formed pyridinium iodide as a dominant quencher, and critical intermediates in the reaction pathway. These mechanistic insights not only provided a complete reaction cycle but also allowed for optimization of reaction efficiency and broadening the substrate scope.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Kimia Hosseini, Chatura Goonesinghe, Hootan Roshandel, Joseph Chang, Kudzanai Nyamayaro, Hyuk-Joon Jung, Paula L. Diaconescu, Parisa Mehrkhodavandi
Summary: This article reports a selective synthesis method of spiro-orthoesters through the coupling reaction of epoxides and lactones catalyzed by alkyl indium, and investigates the mechanism of this reaction using structure-function relationships and computational studies.
Article
Chemistry, Physical
Zheng-Wang Qu, Hui Zhu, Stefan Grimme
Summary: The study on catalytic aromatic chlorination using N-chlorosuccinimides under mild conditions has revealed a novel catalytic mechanism and highlighted the potential role of O=SMe(2) as efficient Cl(+) and H(+) shuttles in the reaction. These mechanistic insights can aid in the rational design of novel dual functional halonium transfer catalysts.
Article
Chemistry, Multidisciplinary
Maria Voccia, Lukas Odenwald, Maximilian Baur, Fei Lin, Laura Falivene, Stefan Mecking, Lucia Caporaso
Summary: Polyethylene materials with in-chain-incorporated keto groups can be achieved by nonalternating copolymerization of ethylene with carbon monoxide using Ni(II) phosphinephenolate catalysts. The mechanism of this reaction involves the isomerization of an alkyl-olefin intermediate as the rate-determining step. The formation of non-alternating incorporation is influenced by ethylene binding, while the formation of alternating motifs is determined by the opening of the C,O-chelate. The crucial feature of these Ni(II) catalysts is the eta(2)-coordination of a P-bound aromatic moiety axially oriented to the metal center, which also affects the competition between the two pathways. The conformational constraints imposed in a 2',6'-dimethoxybiphenyl moiety result in disfavoring ethylene coordination along the alternating incorporation pathway, primarily governed by electronics, while not penalizing the nonalternating chain growth, primarily governed by sterics.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Haifeng Chen, Huifeng Yue, Chen Zhu, Magnus Rueping
Summary: This study describes a nickel-catalyzed three-component reductive carbonylation reaction for the synthesis of aryl-alkyl ketones. Ethyl chloroformate is used as a safe and readily available source of CO, providing an efficient and practical alternative. Experimental and mechanistic studies provide insight into the complexity and sequence of the reaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Review
Chemistry, Inorganic & Nuclear
Vinay Arora, Himani Narjinari, Pran Gobinda Nandi, Akshai Kumar
Summary: This article explores the crucial role of organometallic catalysts in driving organic transformations, with a particular focus on recent advances in pincer-nickel catalyzed reactions. The versatility and control offered by pincer-metal complexes have sparked interest as greener and cheaper alternatives in the field of organometallic chemistry.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Organic
Akash G. Tathe, Nitin T. Patil
Summary: This study reports C(sp(2))-S cross-coupling reactions of aryl iodides and arylsulfonyl hydrazides under ligand-enabled, Au(I)/Au(III) redox catalysis, highlighting the utility of this method for synthesizing various medicinally relevant biaryl sulfones without the need for prefunctionalized aryl coupling partners.
Article
Chemistry, Physical
Jian Luo, Michael T. Davenport, Arianna Carter, Daniel H. Ess, T. Leo Liu
Summary: Ni-catalyzed electrochemical arylation is an attractive method that uses stable Ni catalysts and proceeds efficiently at room temperature. However, the homo-coupling of aryl halides is a major side reaction. Extensive experimental and computational studies were conducted to examine the mechanism of this reaction.
FARADAY DISCUSSIONS
(2023)
Article
Chemistry, Physical
Kerry-Ann Green, Aaron P. Honeycutt, Sierra R. Ciccone, Kyle A. Grice, Andreas Baur, Jeffrey L. Petersen, Jessica M. Hoover
Summary: Ni-catalyzed C-H functionalization reactions are efficient routes to synthesize various functionalized arenes, but the mechanisms are not well understood. The study reports the catalytic and stoichiometric arylation reactions of a nickel(II) metallacycle. Treatment with silver(I)-aryl complexes leads to facile arylation, indicating a redox transmetalation step. The redox transmetalation step may be applicable to other coupling reactions with silver salts as additives.
Review
Chemistry, Organic
Parvathi Santhoshkumar, C. Rajalakshmi, Rehin Sulay, Vibin Ipe Thomas
Summary: Transition metal-catalyzed C-C and C-X (X=heteroatom) homo and cross-coupling reactions have become a momentous strategy for synthesizing natural products, agrochemicals, and pharmaceuticals. Manganese catalysis, with its earth-abundance and eco-friendliness, holds a distinctive identity in this field and has recently gained significant attention.
CURRENT ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Yingze Li, Jeanette A. Krause, Hairong Guan
Summary: The reaction of 1,3,5-((Pr2PO)-Pr-i)(3)C6H3 with different metal complexes leads to the formation of either a POCOP-type mononuclear pincer complex or a tetranuclear species, depending on the ligand to metal ratio. Impurities, such as compounds bearing appended groups, can be formed during the synthesis process if the ligand precursor is contaminated. The structures of the compounds have been studied using X-ray crystallography.
CANADIAN JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Dewrni A. Ekanayake, Arundhoti Chakraborty, Jeanette A. Krause, Hairong Guan
INORGANIC CHEMISTRY
(2020)
Article
Chemistry, Multidisciplinary
Joel D. Collett, Jeanette A. Krause, Hairong Guan
Summary: Inorganic Chemistry teaches students the impact of modifying ligand structures on the reactivity and stability of metal complexes. Through experiments with tetradentate ligands derived from o-phenylenediamine and salicylaldehyde, students can learn synthetic techniques and various characterization methods to understand the concept. The inquiry-guided experimental design helps develop critical thinking skills and apply acquired knowledge to solving research problems in a laboratory course.
JOURNAL OF CHEMICAL EDUCATION
(2021)
Article
Chemistry, Inorganic & Nuclear
Huiguang Dai, Weishi Li, Jeanette A. Krause, Hairong Guan
Summary: Iron hydrides supported by a pincer ligand are versatile hydrogenation catalysts. By replacing CO with isocyanide ligands, two different types of iron hydride complexes were isolated. The activity of these complexes depends on the ligand structure and the reactivity of the substrate.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Joel D. Collett, Rebecca W. Ransohoff, Jeanette A. Krause, Hairong Guan
Summary: A new synthetic route has been developed for the synthesis of cis-((PNP)-P-Cy)Fe(CO)(2)H through reaction with NaBH4, and the Fe-H bond of this iron hydride exhibits remarkable stability towards acids and oxidants, likely proceeding via an initial CO dissociation step in reactions.
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
(2021)
Review
Chemistry, Multidisciplinary
Jonas C. Ott, David Buergy, Hairong Guan, Lutz H. Gade
Summary: Low-valent, low-coordinate 3d metal complexes show high reactivity in challenging bond activation reactions and can act as reagents and catalysts. The use of pincer ligands provides energetic stabilization and steric shielding, enabling the isolation of low-valent compounds with controlled and unique reactivity. T-shaped metal(I) complexes with precisely defined vacant coordination sites exhibit high selectivity in one-electron redox chemistry. Studies on these compounds have led to the discovery of high thermal stability and rarely observed monovalent metal species with monomeric and dimeric structures. The exploration of their reactivity has revealed the tendency of these paramagnetic compounds to undergo one-electron oxidation, resulting in the isolation of metal(II) species with reduced organic ligands. The use of T-shaped complexes as asymmetric catalysts has also shown success in enantioselective hydrodehalogenation reactions. Furthermore, the introduction of redox-active pincer ligands or the formation of homobimetallic systems with two T-shaped units can further diversify this class of complexes. This Account discusses selected examples of iron, cobalt, and nickel pincer complexes, but the electronic structure and radical reactivity can be extended to other pincer systems. The fine-tuning of reactivity in T-shaped complexes can be achieved by using various types of pincer ligands. The study of T-shaped 3d metal complexes is important for advancing base metal catalysis.
ACCOUNTS OF CHEMICAL RESEARCH
(2022)
Article
Chemistry, Inorganic & Nuclear
Joel D. Collett, Jeanette A. Krause, Hairong Guan
Summary: The synthesis of two nickel hydride complexes bearing a pyrrole-derived phosphine ligand was developed and found to exhibit catalytic and reducing abilities, allowing for various chemical reactions under the metal-ligand cooperative mechanism.
Article
Chemistry, Inorganic & Nuclear
Bedraj Pandey, Jeanette A. Krause, Hairong Guan
Summary: This study reports a new Pincer ligand system and its catalytic activity and stability in catalytic hydrogenation and dehydrogenation reactions.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Bedraj Pandey, Jeanette A. Krause, Hairong Guan
Summary: Iron dihydride complexes play a crucial role in various iron-catalyzed reactions. A new study has synthesized iron carbonyl dichloride, hydrido chloride, and dihydride complexes with a methyl-substituted phosphine ligand. The addition of the methyl group alters the molecular geometry and enhances the stability of the dihydride complex, leading to distinct differences in reactivity compared to the previous system.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Mennatullah M. Mokhtar, Joel M. Andersen, Ethan A. Kister, Jordan X. Hopkins, Tom Estier, Fiona Hamilton, Hairong Guan, James Mack, Rebecca A. Haley
Summary: Mechanochemistry through high-speed ball milling is a popular method for organic transformations due to the absence of solvent. Reduction reactions using water as the hydrogen source were investigated in stainless-steel vials with stainless-steel balls. Mechanistic studies suggest that the reduction proceeds via a single electron transfer (SET) pathway, with iron and nickel playing essential roles.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Anubendu Adhikary, Sayantani Saha, N. Sai Kumar, Allen G. G. Oliver, Jeanette A. A. Krause, Hairong Guan
Summary: This research aims to investigate how changing the metal center from nickel to palladium affects the outcome of CO2 reduction. The results show that palladium hydride complexes react rapidly with CO2 to form palladium formate complexes, which can lose CO2 under reduced pressure or in chloroform. In the presence of HBcat, the formate complexes are converted back to palladium hydride species while the formate group is reduced to CH(3)OBcat. These reactions play a significant role in the catalytic reduction of CO2 with the borane.
Article
Chemistry, Inorganic & Nuclear
Bedraj Pandey, Jeanette A. Krause, Hairong Guan
Summary: This study analyzes the formation of degradation products of cis-(iPrPPMeP)FeH2(CO) during the catalytic dehydrogenation reaction. The products include soluble and insoluble species. The soluble component is a mixture of protonated catalyst, oxidation products, and hydrated iron precipitate. Further investigation suggests that the protonated catalyst still exhibits diminished catalytic activity, likely through the displacement of a CO ligand. The formation of the precipitate and the dissociation of the catalyst contribute to the eventual loss of catalytic activity.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Nghia Le, Natalie L. Chuang, Clay M. Oliver, Andrey V. Samoshin, Jack T. Hemphill, Kelsey C. Morris, Stephen N. Hyland, Hairong Guan, Charles Edwin Webster, Timothy B. Clark
Summary: The metal-catalyzed C-H borylation reaction is a valuable method for incorporating boronate esters into organic substrates. However, a comprehensive study of the mechanism has not been reported so far. In this study, both experimental and computational approaches were used to investigate the catalytic mechanism of amine-directed C(sp(2))-H borylation. The results revealed the absence of isotope effects at the functionalized C-H bond and suggested the rate-determining step to be the reassociation of pinacolborane. Additionally, the role of pinacolborane as an additive was examined and found to enhance the reaction rate by acting as an autocatalyst.
Article
Chemistry, Inorganic & Nuclear
Vivian Xu, Bedraj Pandey, J. P. I. Dulmini Jayawardhena, Jeanette A. Krause, Hairong Guan
Summary: This work focuses on nickel complexes derived from two tetrahydrosalen-type proligands. The reaction of H(2)salophan with Ni(OAc)(2)& BULL;4H(2)O generates a dinuclear complex Ni-2(Hsalophan)(2)(OAc)(2) or Na[Ni-2(salophan)(2)(OAc)]. On the other hand, the reaction of H(2)salophan_Me with Ni(OAc)(2)& BULL;4H(2)O yields a mononuclear complex Ni(Hsalophan_Me)(2). These tetrahydrosalen-type complexes are paramagnetic and air sensitive in solution. They can be oxidized to form the salen-type complexes through dehydrogenation of the ligand backbone by O-2 or peroxides.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Dewmi A. Ekanayake, Arundhoti Chakraborty, Jeanette A. Krause, Hairong Guan
Summary: This study identified a series of copper borohydride complexes capable of catalyzing the hydrogenation of aldehydes, with some catalyst mixtures showing higher efficiency, although certain functional groups may inhibit the reaction. Modifying the catalyst structure can impact its catalytic activity.
INORGANIC CHEMISTRY FRONTIERS
(2021)