Article
Chemistry, Inorganic & Nuclear
Jia-Xue Mao, Jiarui Chang, Jie Zhang, Xuenian Chen
Summary: The structures and catalytic reactivity of nickel chloride and thiolate complexes supported by benzene-pyridine-based nonsymmetrical PCN pincer ligands were investigated. The composition and substitution of the pincer backbone were found to have a significant influence on the structures and catalytic reactivity.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Leah Webster, Tobias Kramer, F. Mark Chadwick
Summary: This article demonstrates the attachment of the "POCOP" pincer ligand to titanium in Ti(III) and Ti(IV) complexes for the first time, highlighting its significance in reactions.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Physical
Heiko Schratzberger, Berthold Stoeger, Luis F. Veiros, Karl Kirchner
Summary: In this study, two stable Fe(II) alkyl complexes were successfully synthesized and their catalytic performance in transfer hydrogenation reactions was investigated. The results showed that these complexes exhibited good activity and selectivity for hydrogenation of various alkynes. Through both experimental and theoretical investigations, the researchers also revealed the reaction mechanism.
Article
Chemistry, Multidisciplinary
Alexia N. Kim, Aurapat Ngamnithiporn, Michael D. Bartberger, Brian M. Stoltz
Summary: The first asymmetric trans-selective hydrogenation of 1,3-disubstituted isoquinolines has been developed, resulting in enantioenriched trans-tetrahydroisoquinolines in good yield with high enantioselectivity. Mechanistic studies reveal the crucial role of non-coordinating chlorinated solvents and halide additives in enabling trans-selectivity.
Article
Chemistry, Physical
Zheng Wang, Xiuli Yan, NIng Ma, Song Liu, Peng Han, Huiliang Li, Qaiser Mahmood, Libin Li, Qingbin Liu
Summary: The [fac-PNN]RuH(PPh3)(CO) complex has been identified as a highly efficient catalyst for the hydrogenation of arylcarbamates and their derivatives. This catalytic system offers a promising route for the depolymerization and recycling of polyurethanes. The mechanism of carbamate hydrogenation has been established through DFT calculations and control experiments.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Inorganic & Nuclear
Fei Fang, Jia-Xin Kang, Cong-Qiao Xu, Jiarui Chang, Jie Zhang, Shujun Li, Xuenian Chen
Summary: The influence of the pincer platform composition and substitution on the reactivity and physical properties of pincer complexes is easily explored experimentally, with subtle effects on the molecular structures and thermodynamic stability. The bond lengths and strengths of M-C-ipso, M-P, and M-X were discussed, along with thermochemical balances for different types of pincer complexes.
INORGANIC CHEMISTRY
(2021)
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, Multidisciplinary
Antonio A. Castillo-Garcia, Lucero Gonzalez-Sebastian, Leticia Lomas-Romero, Simon Hernandez-Ortega, Ruben A. Toscano, David Morales-Morales
Summary: This study describes the synthesis of four novel non-symmetric Ni (II)-POCOP pincer complexes with meta-functionalization of benzothiazole or benzimidazole. The complexes were fully characterized in solution and the molecular structures of some were determined using single crystal X-ray diffraction. These Ni (II)-POCOP pincer complexes were efficiently used as catalysts for the synthesis of diarylketones. An important factor affecting the activity of the compounds was found to be the steric properties of the donor groups in the pincer ligands.
NEW JOURNAL OF CHEMISTRY
(2021)
Article
Multidisciplinary Sciences
Dawei Cao, Chen-Chen Li, Huiying Zeng, Yong Peng, Chao-Jun Li
Summary: The study presents a method for constructing C(sp(3))-C(sp(3)) bonds using a nickel-catalyzed reductive coupling of moisture and air-stable hydrazones, with broad substrate scope and harmless by-products. The method demonstrates high functional group compatibility and practicality in the application to biological molecules.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Toshimichi Ohmura, Yuta Takaoka, Michinori Suginome
Summary: The copper-catalyzed silafunctionalization of alkynes using silylboronic ester as a silicon source has made rapid progress. The trans-selective 1,2-addition of silylboronic esters to internal arylalkynes was efficiently promoted by the CuOt-Bu/RCy2P/NaOt-Bu catalysts, with a stereochemical switch to cis-addition observed in reactions utilizing Me-2(i-PrO)Si-B(pin) in hydrocarbon solvents including cyclohexane.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Fu-Peng Wu, Yuan Yang, Dilver Pena Fuentes, Xiao-Feng Wu
Summary: Carbonylation reactions are important in contemporary organic chemistry as they provide access to compounds with carbon monoxide or methyl groups. We report a copper-catalyzed carbonylative catenation and borylation reaction and propose a possible reaction mechanism.
Article
Chemistry, Multidisciplinary
Laura A. Grose, Darren Willcox
Summary: This article reports the synthesis of a well-defined iron(0) complex [(eta(3)-(H2DPB)-D-iPr)Fe(eta(3)-H(2)Bpin)] through the oxidative addition of the H-B bond. This complex shows high efficiency in the hydroboration of various olefins under neat conditions.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Daniel P. Zobernig, Michael Luxner, Berthold Stoeger, Luis F. Veiros, Karl Kirchner
Summary: Efficient hydrogenation of terminal alkenes using molecular hydrogen as the hydrogen source is achieved with well-defined bench stable Mn(I) complexes containing an N-heterocyclic carbene-based PCP pincer ligand as the catalyst. This reaction is environmentally friendly and economically viable, utilizing an inexpensive and abundantly available non-precious metal catalyst. DFT calculations provide mechanistic insight into the catalytic reaction.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Physical
Lijun Lu, Jie Luo, David Milstein
Summary: Sulfones are important in organic synthesis and pharmaceutical chemistry. Direct alpha-alkylation of sulfones with alcohols as the reaction partners offers a promising method for their structural modification. This study reports the successful alpha-alkylation of sulfones using alcohols catalyzed by an earth-abundant manganese complex. The reaction selectivity was greatly improved by the catalyst and the amount of base used. Aromatic and aliphatic alcohols were suitable reagents for the alpha-alkylation of sulfones at low metal catalyst loading, demonstrating the practicality of the developed system.
Article
Chemistry, Multidisciplinary
Jin-fang Chen, Jin-yi Shi, Cong-cong Yin, Xin Cui, Guang-xun Li, Zhuo Tang, Jin-zhong Zhao
Summary: In this study, N-aryl benzimidazoline produced in situ was utilized as a H-2 donor, and through CPA-catalyzed enantioselective transfer hydrogenation, it was converted to C-N axially chiral N-aryl benzimidazole.
NEW JOURNAL OF CHEMISTRY
(2022)
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)
