Article
Chemistry, Inorganic & Nuclear
Priya Singh, Eleanor Stewart-Jones, Melissa C. Denler, Timothy A. Jackson
Summary: High-valent metal-oxo intermediates play a crucial role in oxygen-atom transfer reactions, and changes in metal reduction potential can lead to variations in reaction mechanisms. The rate variations observed for Mn-IV-oxo complexes are primarily controlled by activation enthalpy, indicating a single-step OAT mechanism. This suggests that large variations in sulfoxidation by Mn-IV-oxo centers occur without a change in reaction mechanism.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Inorganic & Nuclear
Wenjuan Zhu, Namita Sharma, Yong-Min Lee, Mohamed E. El-Khouly, Shunichi Fukuzumi, Wonwoo Nam
Summary: This study reports a new method for generating a nonheme iron(IV)-oxo complex using singlet oxygen instead of triplet oxygen and a hydrogen atom donor with relatively strong C-H bonds.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Mian Guo, Jisheng Zhang, Lina Zhang, Yong-Min Lee, Shunichi Fukuzumi, Wonwoo Nam
Summary: In this study, six manganese(IV)-oxo complexes bearing electron-rich and -deficient porphyrins were synthesized and investigated in various oxidation reactions. The research found a reversed reactivity between the electron-rich and -deficient Mn(IV)-oxo porphyrins in hydrogen atom transfer and oxygen atom transfer reactions at different temperatures.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Yubin M. Kwon, Yuri Lee, Anna K. Schmautz, Timothy A. Jackson, Dong Wang
Summary: The recent focus on developing high-valent non-oxo-metal complexes has proven effective in studying their rich chemistry. In this study, a formal mononuclear Ni(IV)-nitrate complex was obtained and its geometric and electronic structures, bonding interactions, and spectroscopic properties were analyzed.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Inorganic & Nuclear
Deepika G. Karmalkar, Mi Sook Seo, Yong-Min Lee, Youngsuk Kim, Eunsung Lee, Ritimukta Sarangi, Shunichi Fukuzumi, Wonwoo Nam
Summary: Binding of Lewis acidic metal ions and Bronsted acid at the metal-oxo group enhances reactivity of high-valent metal-oxo complexes in oxidation reactions. The synthesis, characterization, and reactivity studies of a mononuclear manganese(IV)-oxo complex binding triflic acid were reported in this study. Results show an interesting correlation between the Mn-O stretching frequencies and the reactivities in hydrogen atom transfer and oxygen atom transfer reactions.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Lovleen Kaur, Debasish Mandal
Summary: This article presents a comprehensive density functional theory (DFT) investigation on the role of equatorial sulfur ligation in C-H activation. The study reveals that reactivity increases successively with the enrichment of equatorial sulfur atoms, and computational predictions suggest the synthesis of sulfur-ligated bio-inspired complexes would be more favorable than nitrogen-exclusive ones.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Jin Lin, Qiangsheng Sun, Wei Sun
Summary: The hydroxylation of hexane by two (FeO)-O-IV complexes with pentadentate and tetradentate ligands derived from l-proline was studied using DFT calculations, which showed that both complexes have triplet ground states. The hydrogen atom abstraction processes by both species proceed through a two-state reactivity, indicating that HAA occurs via a low-barrier quintet surface. Additionally, beyond the rebound step, the dissociation path after HAA was also calculated to potentially occur.
Article
Chemistry, Physical
Christopher J. Miller, Yingyue Chang, Christina Wegeberg, Christine J. McKenzie, T. David Waite
Summary: This study demonstrates that the activation of [Fe-III(OH)(tpena)](+) by H2O2 proceeds by the formation of [Fe-III(OOH)(tpena)](+), which undergoes two major reactions to produce HO· and [Fe-IV(O)(tpena)](+). The production of HO· was quantified by a chemiluminescence method, showing that [Fe-IV(O)(tpena)](+) is produced in much larger yields than HO·. Additionally, the study indicates that a reactive high-valent iron-oxo species and HO· can be generated under mild, aqueous ambient conditions, which represents a significant contribution to biomimetic nonheme chemistry in water.
Article
Chemistry, Multidisciplinary
Jyothish Joy, Daniel H. Ess
Summary: The reaction mechanism between non-heme Fe-oxo complexes and alkane C-H bonds involves a hydrogen atom transfer reaction step with a radical pair intermediate. Density functional theory-based quasiclassical direct dynamics trajectories reveal that the post-HAT reaction dynamics and selectivity are determined by dynamic effects. These trajectories provide a new understanding of the reaction pathway selectivity for non-heme Fe-oxo-mediated C-H functionalization reactions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Inorganic & Nuclear
Priya Singh, Melissa C. Denler, Jaycee R. Mayfield, Timothy A. Jackson
Summary: This study investigates the chemoselectivity of Mn-IV-oxo complexes in olefin oxidation and reveals that the selectivity is controlled by the dissociation free energy of the Mn=O bond and the allylic C-H bond.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Multidisciplinary
Aniruddha Dey, Jesse B. Gordon, Therese Albert, Sinan Sabuncu, Maxime A. Siegler, Samantha N. MacMillan, Kyle M. Lancaster, Pierre Moenne-Loccoz, David P. Goldberg
Summary: A new nonheme iron(II) complex was reported, which reacts with NO(g) to form a stable mononitrosyl complex. The mononitrosyl complex exhibits highly activated characteristics and can rapidly convert to N2O in the absence of an exogenous reductant.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Guilherme L. Tripodi, Magda M. J. Dekker, Jana Roithova, Lawrence Que
Summary: Reactivity of non-heme iron(IV)-oxo complexes is mainly controlled by the ligands, with complexes featuring tetradentate ligands showing the highest reactivity. Fine-tuning of the reactivity of these complexes can be achieved by attaching additional ligands in solution, with the ArIO oxidant playing a previously unknown role. The reactivity of the complexes correlates with the Fe=O and FeO-H stretching vibrations, with the most reactive complex in the series having the weakest Fe=O bond and forming the strongest FeO-H bond.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Inorganic & Nuclear
Sandip Munshi, Arup Sinha, Solomon Yiga, Sridhar Banerjee, Reena Singh, Md Kamal Hossain, Matti Haukka, Andrei Felipe Valiati, Ricardo Dagnoni Huelsmann, Edmar Martendal, Rosely Peralta, Fernando Xavier, Ola F. Wendt, Tapan K. Paine, Ebbe Nordlander
Summary: A series of iron(II) complexes with different ligands were isolated and characterized. The steric and electronic factors were found to affect the reactivity of iron(IV)-oxo complexes. The results highlight the importance of ligand environment in controlling the reactivity of these complexes.
DALTON TRANSACTIONS
(2022)
Review
Chemistry, Inorganic & Nuclear
Emma N. Cook, Charles W. Machan
Summary: Research efforts on bioinspired and biomimetic complexes for harnessing the oxidizing power of O-2 have focused more on Fe- and Cu-based enzymes, with comparatively less attention on Mn-based enzymes. Progress has been made in the development of bioinspired mononuclear Mn complexes for O-2 activation, emphasizing design parameters and mechanistic trends.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Multidisciplinary
Ranjana Gupta, Xiao-Xi Li, Youngseob Lee, Mi Sook Seo, Yong-Min Lee, Sachiko Yanagisawa, Minoru Kubo, Ritimukta Sarangi, Kyung-Bin Cho, Shunichi Fukuzumi, Wonwoo Nam
Summary: In this study, heme compound II models with electron-deficient and -rich porphyrins were synthesized and investigated for their activity in chemoselectivity and disproportionation reactions using cyclohexene as a probe. The results showed that different compound II models exhibited different chemoselectivity towards the oxidation of cyclohexene, which may be attributed to the disproportionation process and the formation of active oxidants.
Article
Biochemistry & Molecular Biology
Hyeri Jeon, Hugo Vazquez-Lima, Haewon Jeong, Kyung-Bin Cho, Seungwoo Hong
Summary: Dinuclear zinc(II) complexes can accelerate the cleavage of phosphoester bonds under basic conditions, with hydrogen bonding between water and phosphoester assisting in nucleophilic attack. These compounds exhibit fast synthetic Zn-based model performing phosphatase-like activity.
JOURNAL OF BIOLOGICAL INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Sudakar Padmanaban, Jonghoon Choi, Hugo Vazquez-Lima, Donghwi Ko, Dagyum Yoo, Jinseong Gwak, Kyung-Bin Cho, Yunho Lee
Summary: This study presents a synthetic approach to the conversion of NOx utilizing a bifunctional metal catalyst, which effectively converts Ni-NOx to Ni-NO and transfers the nitroso group to organic substrates. The successful catalytic production of oximes from benzyl halides using NaNO2 as a substrate is achieved under mild conditions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Inorganic & Nuclear
Younwoo Park, Seonghan Kim, Kyungmin Kim, Bongki Shin, Youngchae Jang, Kyung-Bin Cho, Jaeheung Cho
Summary: This study reports the structure and spectroscopic characteristics of high-valent transition metal-hydroxide complexes and demonstrates their oxidative reactivity, highlighting their significance in catalytic reactions.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Junhyeok Seo, Seungjin Song, Wonjung Lee, Youngseob Lee, Kyung-Bin Cho, Junseong Lee
Summary: The reorganization of catalysts induced by electron transfer plays a crucial role in catalytic reactivity. In this study, the electron-induced reorganization patterns of Co complexes with neutral N-donor ligands were investigated. The different ligand characteristics led to different reorganization patterns, such as the release of solvent or bond dissociation. Furthermore, the metal-ligand cooperative redox steps shifted the reactivity of Co(I) towards CO2 reduction, and the amine pendant stabilized the CO2 reduction intermediate through hydrogen bonding.
INORGANIC CHEMISTRY
(2023)
Review
Chemistry, Physical
Young Hyun Hong, Yong-Min Lee, Wonwoo Nam, Shunichi Fukuzumi
Summary: This review provides an overview of the functional model reactions of photosystem II (PSII) and photosystem I (PSI) for photocatalytic water oxidation and reduction, respectively. The roles of high-valent metal-oxo, -hydroperoxo,-peroxo, and-superoxo complexes as reaction intermediates in photocatalytic water oxidation are discussed, as well as the catalytic mechanisms of water oxidation. The roles of metal hydride complexes in hydrogen evolution and NAD+ reduction to NADH are also explored. The aim is to construct molecular artificial photosynthetic systems that can split water into H2 and O2 in a 2:1 ratio, thus achieving artificial photosynthesis at the molecular level.
Article
Chemistry, Inorganic & Nuclear
Kunwoo Lee, Nara Kim, Kyung-Bin Cho, Yunho Lee
Summary: A phosphide nickel(II) phenoxide pincer complex reacts with CO to form a nickel(0) monocarbonyl complex with a phosphinite moiety. The reaction involves a 2-electron reduction of nickel(II) induced by CO coordination, resulting in the formation of a P-O bond. Kinetic experiments show that phenolate species with electron-withdrawing groups react faster than those with electron-donating groups.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Wenjuan Zhu, Namita Sharma, Yong-Min Lee, Mohamed E. El-Khouly, Shunichi Fukuzumi, Wonwoo Nam
Summary: This study reports a new method for generating a nonheme iron(IV)-oxo complex using singlet oxygen instead of triplet oxygen and a hydrogen atom donor with relatively strong C-H bonds.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Jie Chen, Wenxun Song, Jinping Yao, Zhimin Wu, Yong-Min Lee, Yong Wang, Wonwoo Nam, Bin Wang
Summary: The use of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) as a solvent with strong hydrogen bond donor capability enables remote C-H hydroxylation in the presence of basic aza-heteroaromatic rings. This strategy represents a promising alternative to protection approaches relying on precomplexation with strong Lewis and/or Bronsted acids.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Wenjuan Zhu, Akhilesh Kumar, Jin Xiong, Macon J. Abernathy, Xiao-Xi Li, Mi Sook Seo, Yong-Min Lee, Ritimukta Sarangi, Yisong Guo, Wonwoo Nam
Summary: The nature of reactive intermediates and the cis-dihydroxylation mechanism of arenes and olefins have been studied extensively in the past few decades. In this study, the reaction between a spectroscopically characterized mononuclear nonheme iron(III)-peroxo complex and olefins and naphthalene derivatives has been investigated. The results show that the nonheme iron(III)-peroxo complex is a nucleophile and reacts with olefins and naphthalenes to yield cis-diol products. This study presents the first example of cis-dihydroxylation of substrates by a nonheme iron(III)-peroxo complex.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Lina Zhang, Mi Sook Seo, Yunhee Choi, Roman Ezhov, Olga Maximova, Deesha D. Malik, Maggie Ng, Yong-Min Lee, Ritimukta Sarangi, Yulia N. Pushkar, Kyung-Bin Cho, Wonwoo Nam
Summary: A high-valent manganese(IV)-hydroxo porphyrin pi-cation radical complex, [Mn(IV)(OH)(Porp+center dot)(X)]+, was synthesized and characterized spectroscopically. The Mn porphyrin intermediate showed high reactivity in alkane hydroxylation, oxygen atom transfer, and water oxidation reactions. This study provides the first example of a manganese Cpd I model compound with a porphyrin pi cation radical ligand that exhibits high reactivity in oxidation reactions, including water oxidation.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Maggie Ng, Kyung-Bin Cho
Summary: It has been discovered that (MnO)-O-IV species with neutral ligands undergo C-H activation reactions through excited state reactivity (ESR), where a valence electron in the (MnO)-O-IV moiety is excited to a higher orbital to create a stronger reactant. The study extends this finding to a (MnO)-O-IV compound with a negatively charged ligand ([Mn-IV(O)(DPAQ)](+)) and investigates it using density functional theory. The results show that ESR is still preferred in this case, and the ligand charge may only have an indirect impact on ESR, while ligand rigidity is proposed to directly affect the ESR rate. Furthermore, a new beta-electron transfer pathway is discovered, where three key orbitals mix to deliver the incoming electron to its final orbital position. This study supports the idea that ESR may be more common in C-H activation reactions of (MnO)-O-IV compounds than previously known.
BULLETIN OF THE KOREAN CHEMICAL SOCIETY
(2023)
Review
Chemistry, Physical
Young Hyun Hong, Yong-Min Lee, Wonwoo Nam, Shunichi Fukuzumi
Summary: Solar fuel production from water has gained attention for its potential to address energy and environmental concerns. Dual- and multi-functional photocatalytic systems, such as polymeric cyano-bridged metal complexes and metal-organic frameworks, have been developed for water oxidation, H-2 production, CO2 reduction, and H2O2 production.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Chemistry, Inorganic & Nuclear
Zhimin Wu, Dongru Sun, Yong-Min Lee, Yufen Zhao, Wonwoo Nam, Yong Wang
Summary: The novel free radical chain mechanism of the Ni(II)-mediated oxidation of cyclohexane by mCPBA is investigated using density functional theory calculations. The involvement of a long speculated Ni-II-oxyl species is ruled out, and it is found that an aroyloxy radical (mCBA) and a Ni-III-hydroxyl species formed by O-O homolysis of a Ni-II-mCPBA complex are the active species in the C-H bond activation. These mechanistic findings support the free radical chain mechanism and enrich the mechanistic knowledge of metal-peracid oxidation systems containing transition metals after group 8.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Yong-Min Lee, Wonwoo Nam, Shunichi Fukuzumi
Summary: This perspective article discusses the redox catalysis of organic and inorganic molecules via photoinduced electron transfer, which is highly relevant for various important photoredox reactions. The combination of organic and inorganic photoredox catalysis with thermal transition metal redox catalysis enables overall photocatalytic redox reactions that would not be feasible otherwise. The article also examines the role of excited states of electron donors and acceptors in the photoinduced electron-transfer reactions, providing valuable insights for employing redox catalysts via photoinduced electron transfer.
Article
Chemistry, Multidisciplinary
Hyeri Jeon, Jisoo Kim, Jin Kim, Kyung-Bin Cho, Seungwoo Hong
Summary: We report the synthesis of an end-on dinuclear Mn(ii) azide complex and the investigation of its reactivity through experimental and theoretical studies.
CHEMICAL COMMUNICATIONS
(2022)
