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Shunichi Fukuzumi - One of the best experts on this subject based on the ideXlab platform.
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unified mechanism of oxygen atom transfer and hydrogen atom transfer reactions with a triflic acid bound nonheme manganese iv oxo complex via outer sphere electron transfer
Journal of the American Chemical Society, 2019Co-Authors: Kei Ohkubo, Shunichi FukuzumiAbstract:Outer-sphere electron transfer from styrene, Thioanisole, and toluene derivatives to a triflic acid (HOTf)-bound nonheme Mn(IV)–oxo complex, [(N4Py)MnIV(O)]2+–(HOTf)2 (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), has been shown to be the rate-determining step of different types of redox reactions such as epoxidation, sulfoxidation, and hydroxylation of styrene, Thioanisole, and toluene derivatives, respectively, by [(N4Py)MnIV(O)]2+–(HOTf)2. The rate constants of HOTf-promoted epoxidation of all styrene derivatives with [(N4Py)MnIV(O)]2+ and electron transfer from electron donors to [(N4Py)MnV(O)]2+ exhibit a remarkably unified correlation with the driving force of outer-sphere electron transfer in light of the Marcus theory of electron transfer. The same electron-transfer driving force dependence is observed in the oxygen atom transfer from [(N4Py)MnIV(O)]2+–(HOTf)2 to Thioanisole derivatives as well as in the hydrogen atom transfer from toluene derivatives to [(N4Py)MnIV(O)]2+–(HOTf)2. ...
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unified mechanism of oxygen atom transfer and hydrogen atom transfer reactions with a triflic acid bound nonheme manganese iv oxo complex via outer sphere electron transfer
Journal of the American Chemical Society, 2019Co-Authors: Yongmin Lee, Shunichi Fukuzumi, Wonwoo Nam, Kei Ohkubo, Surin Kim, Kyung-ha KimAbstract:Outer-sphere electron transfer from styrene, Thioanisole, and toluene derivatives to a triflic acid (HOTf)-bound nonheme Mn(IV)-oxo complex, [(N4Py)MnIV(O)]2+-(HOTf)2 (N4Py = N, N-bis(2-pyridylmethyl)- N-bis(2-pyridyl)methylamine), has been shown to be the rate-determining step of different types of redox reactions such as epoxidation, sulfoxidation, and hydroxylation of styrene, Thioanisole, and toluene derivatives, respectively, by [(N4Py)MnIV(O)]2+-(HOTf)2. The rate constants of HOTf-promoted epoxidation of all styrene derivatives with [(N4Py)MnIV(O)]2+ and electron transfer from electron donors to [(N4Py)MnV(O)]2+ exhibit a remarkably unified correlation with the driving force of outer-sphere electron transfer in light of the Marcus theory of electron transfer. The same electron-transfer driving force dependence is observed in the oxygen atom transfer from [(N4Py)MnIV(O)]2+-(HOTf)2 to Thioanisole derivatives as well as in the hydrogen atom transfer from toluene derivatives to [(N4Py)MnIV(O)]2+-(HOTf)2. Thus, mechanisms of oxygen atom transfer (epoxidation and sulfoxidation) reactions of styrene and Thioanisole derivatives and hydrogen atom transfer (hydroxylation) reactions of toluene derivatives by [(N4Py)MnIV(O)]2+-(HOTf)2 have been unified for the first time as the same reaction pathway via outer-sphere electron transfer, followed by the fast bond-forming step, which exhibits the singly unified electron-transfer driving force dependence of the rate constants as outer-sphere electron-transfer reactions. In the case of the epoxidation of cis-stilbene by [(N4Py)MnIV(O)]2+-(HOTf)2, the isomerization of cis-stilbene radical cation to trans-stilbene radical cation occurs after outer-sphere electron transfer from cis-stilbene to [(N4Py)MnIV(O)]2+-(HOTf)2 to yield trans-stilbene oxide selectively, which is also taken as evidence for the occurrence of electron transfer in the acid-catalyzed epoxidation.
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Unified Mechanism of Oxygen Atom Transfer and Hydrogen Atom Transfer Reactions with a Triflic Acid-Bound Nonheme Manganese(IV)–Oxo Complex via Outer-Sphere Electron Transfer
2019Co-Authors: Yongmin Lee, Wonwoo Nam, Kei Ohkubo, Surin Kim, Kyung-ha Kim, Shunichi FukuzumiAbstract:Outer-sphere electron transfer from styrene, Thioanisole, and toluene derivatives to a triflic acid (HOTf)-bound nonheme Mn(IV)–oxo complex, [(N4Py)MnIV(O)]2+–(HOTf)2 (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), has been shown to be the rate-determining step of different types of redox reactions such as epoxidation, sulfoxidation, and hydroxylation of styrene, Thioanisole, and toluene derivatives, respectively, by [(N4Py)MnIV(O)]2+–(HOTf)2. The rate constants of HOTf-promoted epoxidation of all styrene derivatives with [(N4Py)MnIV(O)]2+ and electron transfer from electron donors to [(N4Py)MnV(O)]2+ exhibit a remarkably unified correlation with the driving force of outer-sphere electron transfer in light of the Marcus theory of electron transfer. The same electron-transfer driving force dependence is observed in the oxygen atom transfer from [(N4Py)MnIV(O)]2+–(HOTf)2 to Thioanisole derivatives as well as in the hydrogen atom transfer from toluene derivatives to [(N4Py)MnIV(O)]2+–(HOTf)2. Thus, mechanisms of oxygen atom transfer (epoxidation and sulfoxidation) reactions of styrene and Thioanisole derivatives and hydrogen atom transfer (hydroxylation) reactions of toluene derivatives by [(N4Py)MnIV(O)]2+–(HOTf)2 have been unified for the first time as the same reaction pathway via outer-sphere electron transfer, followed by the fast bond-forming step, which exhibits the singly unified electron-transfer driving force dependence of the rate constants as outer-sphere electron-transfer reactions. In the case of the epoxidation of cis-stilbene by [(N4Py)MnIV(O)]2+–(HOTf)2, the isomerization of cis-stilbene radical cation to trans-stilbene radical cation occurs after outer-sphere electron transfer from cis-stilbene to [(N4Py)MnIV(O)]2+–(HOTf)2 to yield trans-stilbene oxide selectively, which is also taken as evidence for the occurrence of electron transfer in the acid-catalyzed epoxidation
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unified view of oxidative c h bond cleavage and sulfoxidation by a nonheme iron iv oxo complex via lewis acid promoted electron transfer
Inorganic Chemistry, 2014Co-Authors: Jiyun Park, Wonwoo Nam, Yuma Morimoto, Yongmin Lee, Shunichi FukuzumiAbstract:Oxidative C–H bond cleavage of toluene derivatives and sulfoxidation of Thioanisole derivatives by a nonheme iron(IV)–oxo complex, [(N4Py)FeIV(O)]2+ (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), were remarkably enhanced by the presence of triflic acid (HOTf) and Sc(OTf)3 in acetonitrile at 298 K. All the logarithms of the observed second-order rate constants of both the oxidative C–H bond cleavage and sulfoxidation reactions exhibit remarkably unified correlations with the driving forces of proton-coupled electron transfer (PCET) and metal ion-coupled electron transfer (MCET) in light of the Marcus theory of electron transfer when the differences in the formation constants of precursor complexes between PCET and MCET were taken into account, respectively. Thus, the mechanisms of both the oxidative C–H bond cleavage of toluene derivatives and sulfoxidation of Thioanisole derivatives by [(N4Py)FeIV(O)]2+ in the presence of HOTf and Sc(OTf)3 have been unified as the rate-determining electron...
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mechanisms of sulfoxidation catalyzed by high valent intermediates of heme enzymes electron transfer vs oxygen transfer mechanism
Journal of the American Chemical Society, 1999Co-Authors: Yoshio Goto, Toshitaka Matsui, Shinichi Ozaki, Yoshihito Watanabe, Shunichi FukuzumiAbstract:Mechanisms of sulfoxidation catalyzed by high-valent intermediates of heme enzymes have been investigated by direct observation of sulfide-induced reduction of three different compound I species including HRP (horseradish peroxidase), the His64Ser myoglobin (Mb) mutant, and OFeIVTMP+• (1) (TMP = 5,10,15,20-tetramesitylporphyrin dianion). The reaction of Thioanisole and compound I of HRP (10 μM, pH 7.0, 298 K) gives the resting state of HRP with accumulation of compound II as an intermediate. The yield of sulfoxide by a stoichiometric reaction of HRP compound I with Thioanisole was only 25% ± 5%. On the other hand, the same sulfoxidation by both 1 and His64Ser Mb compound I exclusively exhibited a two-electron process, resulting in quantitative formation of sulfoxide. When 1,5-dithiacyclooctane (DTCO) is employed as a substrate, the reaction of His64Ser Mb compound I with DTCO exhibits rapid formation of compound II, which decays to the ferric state due to the low oxidation potential of DTCO. The observed ...
Wonwoo Nam - One of the best experts on this subject based on the ideXlab platform.
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unified mechanism of oxygen atom transfer and hydrogen atom transfer reactions with a triflic acid bound nonheme manganese iv oxo complex via outer sphere electron transfer
Journal of the American Chemical Society, 2019Co-Authors: Yongmin Lee, Shunichi Fukuzumi, Wonwoo Nam, Kei Ohkubo, Surin Kim, Kyung-ha KimAbstract:Outer-sphere electron transfer from styrene, Thioanisole, and toluene derivatives to a triflic acid (HOTf)-bound nonheme Mn(IV)-oxo complex, [(N4Py)MnIV(O)]2+-(HOTf)2 (N4Py = N, N-bis(2-pyridylmethyl)- N-bis(2-pyridyl)methylamine), has been shown to be the rate-determining step of different types of redox reactions such as epoxidation, sulfoxidation, and hydroxylation of styrene, Thioanisole, and toluene derivatives, respectively, by [(N4Py)MnIV(O)]2+-(HOTf)2. The rate constants of HOTf-promoted epoxidation of all styrene derivatives with [(N4Py)MnIV(O)]2+ and electron transfer from electron donors to [(N4Py)MnV(O)]2+ exhibit a remarkably unified correlation with the driving force of outer-sphere electron transfer in light of the Marcus theory of electron transfer. The same electron-transfer driving force dependence is observed in the oxygen atom transfer from [(N4Py)MnIV(O)]2+-(HOTf)2 to Thioanisole derivatives as well as in the hydrogen atom transfer from toluene derivatives to [(N4Py)MnIV(O)]2+-(HOTf)2. Thus, mechanisms of oxygen atom transfer (epoxidation and sulfoxidation) reactions of styrene and Thioanisole derivatives and hydrogen atom transfer (hydroxylation) reactions of toluene derivatives by [(N4Py)MnIV(O)]2+-(HOTf)2 have been unified for the first time as the same reaction pathway via outer-sphere electron transfer, followed by the fast bond-forming step, which exhibits the singly unified electron-transfer driving force dependence of the rate constants as outer-sphere electron-transfer reactions. In the case of the epoxidation of cis-stilbene by [(N4Py)MnIV(O)]2+-(HOTf)2, the isomerization of cis-stilbene radical cation to trans-stilbene radical cation occurs after outer-sphere electron transfer from cis-stilbene to [(N4Py)MnIV(O)]2+-(HOTf)2 to yield trans-stilbene oxide selectively, which is also taken as evidence for the occurrence of electron transfer in the acid-catalyzed epoxidation.
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Unified Mechanism of Oxygen Atom Transfer and Hydrogen Atom Transfer Reactions with a Triflic Acid-Bound Nonheme Manganese(IV)–Oxo Complex via Outer-Sphere Electron Transfer
2019Co-Authors: Yongmin Lee, Wonwoo Nam, Kei Ohkubo, Surin Kim, Kyung-ha Kim, Shunichi FukuzumiAbstract:Outer-sphere electron transfer from styrene, Thioanisole, and toluene derivatives to a triflic acid (HOTf)-bound nonheme Mn(IV)–oxo complex, [(N4Py)MnIV(O)]2+–(HOTf)2 (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), has been shown to be the rate-determining step of different types of redox reactions such as epoxidation, sulfoxidation, and hydroxylation of styrene, Thioanisole, and toluene derivatives, respectively, by [(N4Py)MnIV(O)]2+–(HOTf)2. The rate constants of HOTf-promoted epoxidation of all styrene derivatives with [(N4Py)MnIV(O)]2+ and electron transfer from electron donors to [(N4Py)MnV(O)]2+ exhibit a remarkably unified correlation with the driving force of outer-sphere electron transfer in light of the Marcus theory of electron transfer. The same electron-transfer driving force dependence is observed in the oxygen atom transfer from [(N4Py)MnIV(O)]2+–(HOTf)2 to Thioanisole derivatives as well as in the hydrogen atom transfer from toluene derivatives to [(N4Py)MnIV(O)]2+–(HOTf)2. Thus, mechanisms of oxygen atom transfer (epoxidation and sulfoxidation) reactions of styrene and Thioanisole derivatives and hydrogen atom transfer (hydroxylation) reactions of toluene derivatives by [(N4Py)MnIV(O)]2+–(HOTf)2 have been unified for the first time as the same reaction pathway via outer-sphere electron transfer, followed by the fast bond-forming step, which exhibits the singly unified electron-transfer driving force dependence of the rate constants as outer-sphere electron-transfer reactions. In the case of the epoxidation of cis-stilbene by [(N4Py)MnIV(O)]2+–(HOTf)2, the isomerization of cis-stilbene radical cation to trans-stilbene radical cation occurs after outer-sphere electron transfer from cis-stilbene to [(N4Py)MnIV(O)]2+–(HOTf)2 to yield trans-stilbene oxide selectively, which is also taken as evidence for the occurrence of electron transfer in the acid-catalyzed epoxidation
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Mutable Properties of Nonheme Iron(III)–Iodosylarene Complexes Result in the Elusive Multiple-Oxidant Mechanism
2017Co-Authors: Yiran Kang, Wonwoo Nam, Kyung-bin Cho, Wei Sun, Chungu Xia, Yong WangAbstract:Although nonheme iron(III)–iodosylarene complexes present amazing oxidative efficiency and selectivity, the nature of such complexes and related oxidation mechanism are still unsolved after decades of experimental efforts. Density functional calculations were employed to explore the structure–reactivity relationship of the iron(III)–iodosylbenzene complex, [FeIII(tpena–) (PhIO)]2+ (1), in Thioanisole sulfoxidation. Our theoretical work revealed that complex 1 can evolve into two resonance valence-bond electronic structures (a high-valent iron–oxo species and a monomeric PhIO species) in Thioanisole sulfoxidation to present different reaction mechanisms (the novel bond-cleavage coupled electron transfer mechanism or the direct oxygen-atom transfer mechanism) as a response to different substrate attack orientations
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unified view of oxidative c h bond cleavage and sulfoxidation by a nonheme iron iv oxo complex via lewis acid promoted electron transfer
Inorganic Chemistry, 2014Co-Authors: Jiyun Park, Wonwoo Nam, Yuma Morimoto, Yongmin Lee, Shunichi FukuzumiAbstract:Oxidative C–H bond cleavage of toluene derivatives and sulfoxidation of Thioanisole derivatives by a nonheme iron(IV)–oxo complex, [(N4Py)FeIV(O)]2+ (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), were remarkably enhanced by the presence of triflic acid (HOTf) and Sc(OTf)3 in acetonitrile at 298 K. All the logarithms of the observed second-order rate constants of both the oxidative C–H bond cleavage and sulfoxidation reactions exhibit remarkably unified correlations with the driving forces of proton-coupled electron transfer (PCET) and metal ion-coupled electron transfer (MCET) in light of the Marcus theory of electron transfer when the differences in the formation constants of precursor complexes between PCET and MCET were taken into account, respectively. Thus, the mechanisms of both the oxidative C–H bond cleavage of toluene derivatives and sulfoxidation of Thioanisole derivatives by [(N4Py)FeIV(O)]2+ in the presence of HOTf and Sc(OTf)3 have been unified as the rate-determining electron...
Prabha Vadivelu - One of the best experts on this subject based on the ideXlab platform.
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a density functional theory study on comparing the reactivity of mn 13 tmc ooh 2 and mn 13 tmc o2 for the sulfoxidation of Thioanisole elucidation of substrate and non redox metal ion effects
Inorganic Chemistry, 2021Co-Authors: Krithika Ganesan, Ilakya Kaliyaperumal, Prabha VadiveluAbstract:The reactivities of [Mn(13-TMC)(OOH)]2+ (1) and [Mn(13-TMC)(O2)]+ (2) in the sulfoxidation of Thioanisole have been compared using density functional theory methods. The orientation of the 13-TMC ligand and substrate and non-redox metal ion effects have been considered to improve the oxidation efficiency of 1 and 2. In 1, the syn- and anti-orientation of the 13-TMC ligand do not change the coordination of the Mn ion. In contrast, the orientation of the 13-TMC ligand regulates the geometry of 2, wherein the syn-13-TMC ligand exhibits the MnIII-peroxo (2hs and 2ls) species, while the anti-13-TMC shows the MnII-superoxo (2'hs and 2'ls) species. However, the MnII-superoxo species are found to be less stable than the MnIII-peroxo complexes by around +26.6 kcal/mol. The ground state geometries of 1 and 2 with the syn-13-TMC ligand are found to be more stable in the high- (S = 2) spin states (1hs and 2hs) than the low- (S = 1) spin complexes (1ls and 2ls), by +15.6 and +25.5 kcal/mol, respectively. The computed mechanistic pathways clearly indicate that the sulfoxidation of Thioanisole by 1hs is kinetically (by +16.6 to +46.1 kcal/mol) and thermodynamically (+14.4 to +56.1 kcal/mol) more preferred than 1ls, 2hs, and 2ls species. This is mainly due to the feasible heterolytic O1-O2 bond cleavage followed by the proton transfer step. In addition, the molecular electrostatic potential analysis indicates that the higher oxidation efficacy of 1hs than 2hs is due to the -OOH moiety. The reactivity of 1hs is further enhanced by incorporating electron donating substituents in Thioanisole, wherein the p-NH2 Thioanisole decreases the ΔG‡ of 1hs by 28%. Interestingly, the incorporation of non-redox metal ions (Mn+ = Sc3+, Y3+, Mg2+, and Zn2+) improves the reactivity of 2hs, wherein the non-redox metal ions tend to bind with the oxygen atoms of 2hs and subsequently shift the one-electron reduction potential (E0(red) vs SCE) toward the positive side. The positive shift in the E0(red) is more evident in 2hs-Y3+ that significantly decreases the ΔG‡ of 2hs by 58.7%, which is in fact lower than the ΔG‡ of 1hs by +2.0 kcal/mol. Hence, in the presence of Y3+, the reactivity of 2hs is comparable with 1hs in the sulfoxidation of Thioanisole.
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A Density Functional Theory Study on Comparing the Reactivity of [Mn(13-TMC)(OOH)]2+ and [Mn(13-TMC)(O2)]+ for the Sulfoxidation of Thioanisole: Elucidation of Substrate and Non-Redox Metal Ion Effects
'American Chemical Society (ACS)', 2021Co-Authors: Krithika Ganesan, Ilakya Kaliyaperumal, Prabha VadiveluAbstract:The reactivities of [Mn(13-TMC)(OOH)]2+ (1) and [Mn(13-TMC)(O2)]+ (2) in the sulfoxidation of Thioanisole have been compared using density functional theory methods. The orientation of the 13-TMC ligand and substrate and non-redox metal ion effects have been considered to improve the oxidation efficiency of 1 and 2. In 1, the syn- and anti-orientation of the 13-TMC ligand do not change the coordination of the Mn ion. In contrast, the orientation of the 13-TMC ligand regulates the geometry of 2, wherein the syn-13-TMC ligand exhibits the MnIII-peroxo (2hs and 2ls) species, while the anti-13-TMC shows the MnII-superoxo (2′hs and 2′ls) species. However, the MnII-superoxo species are found to be less stable than the MnIII-peroxo complexes by around +26.6 kcal/mol. The ground state geometries of 1 and 2 with the syn-13-TMC ligand are found to be more stable in the high- (S = 2) spin states (1hs and 2hs) than the low- (S = 1) spin complexes (1ls and 2ls), by +15.6 and +25.5 kcal/mol, respectively. The computed mechanistic pathways clearly indicate that the sulfoxidation of Thioanisole by 1hs is kinetically (by +16.6 to +46.1 kcal/mol) and thermodynamically (+14.4 to +56.1 kcal/mol) more preferred than 1ls, 2hs, and 2ls species. This is mainly due to the feasible heterolytic O1-O2 bond cleavage followed by the proton transfer step. In addition, the molecular electrostatic potential analysis indicates that the higher oxidation efficacy of 1hs than 2hs is due to the −OOH moiety. The reactivity of 1hs is further enhanced by incorporating electron donating substituents in Thioanisole, wherein the p-NH2 Thioanisole decreases the ΔG‡ of 1hs by 28%. Interestingly, the incorporation of non-redox metal ions (Mn+ = Sc3+, Y3+, Mg2+, and Zn2+) improves the reactivity of 2hs, wherein the non-redox metal ions tend to bind with the oxygen atoms of 2hs and subsequently shift the one-electron reduction potential (E0(red) vs SCE) toward the positive side. The positive shift in the E0(red) is more evident in 2hs-Y3+ that significantly decreases the ΔG‡ of 2hs by 58.7%, which is in fact lower than the ΔG‡ of 1hs by +2.0 kcal/mol. Hence, in the presence of Y3+, the reactivity of 2hs is comparable with 1hs in the sulfoxidation of Thioanisole
Kei Ohkubo - One of the best experts on this subject based on the ideXlab platform.
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unified mechanism of oxygen atom transfer and hydrogen atom transfer reactions with a triflic acid bound nonheme manganese iv oxo complex via outer sphere electron transfer
Journal of the American Chemical Society, 2019Co-Authors: Kei Ohkubo, Shunichi FukuzumiAbstract:Outer-sphere electron transfer from styrene, Thioanisole, and toluene derivatives to a triflic acid (HOTf)-bound nonheme Mn(IV)–oxo complex, [(N4Py)MnIV(O)]2+–(HOTf)2 (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), has been shown to be the rate-determining step of different types of redox reactions such as epoxidation, sulfoxidation, and hydroxylation of styrene, Thioanisole, and toluene derivatives, respectively, by [(N4Py)MnIV(O)]2+–(HOTf)2. The rate constants of HOTf-promoted epoxidation of all styrene derivatives with [(N4Py)MnIV(O)]2+ and electron transfer from electron donors to [(N4Py)MnV(O)]2+ exhibit a remarkably unified correlation with the driving force of outer-sphere electron transfer in light of the Marcus theory of electron transfer. The same electron-transfer driving force dependence is observed in the oxygen atom transfer from [(N4Py)MnIV(O)]2+–(HOTf)2 to Thioanisole derivatives as well as in the hydrogen atom transfer from toluene derivatives to [(N4Py)MnIV(O)]2+–(HOTf)2. ...
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unified mechanism of oxygen atom transfer and hydrogen atom transfer reactions with a triflic acid bound nonheme manganese iv oxo complex via outer sphere electron transfer
Journal of the American Chemical Society, 2019Co-Authors: Yongmin Lee, Shunichi Fukuzumi, Wonwoo Nam, Kei Ohkubo, Surin Kim, Kyung-ha KimAbstract:Outer-sphere electron transfer from styrene, Thioanisole, and toluene derivatives to a triflic acid (HOTf)-bound nonheme Mn(IV)-oxo complex, [(N4Py)MnIV(O)]2+-(HOTf)2 (N4Py = N, N-bis(2-pyridylmethyl)- N-bis(2-pyridyl)methylamine), has been shown to be the rate-determining step of different types of redox reactions such as epoxidation, sulfoxidation, and hydroxylation of styrene, Thioanisole, and toluene derivatives, respectively, by [(N4Py)MnIV(O)]2+-(HOTf)2. The rate constants of HOTf-promoted epoxidation of all styrene derivatives with [(N4Py)MnIV(O)]2+ and electron transfer from electron donors to [(N4Py)MnV(O)]2+ exhibit a remarkably unified correlation with the driving force of outer-sphere electron transfer in light of the Marcus theory of electron transfer. The same electron-transfer driving force dependence is observed in the oxygen atom transfer from [(N4Py)MnIV(O)]2+-(HOTf)2 to Thioanisole derivatives as well as in the hydrogen atom transfer from toluene derivatives to [(N4Py)MnIV(O)]2+-(HOTf)2. Thus, mechanisms of oxygen atom transfer (epoxidation and sulfoxidation) reactions of styrene and Thioanisole derivatives and hydrogen atom transfer (hydroxylation) reactions of toluene derivatives by [(N4Py)MnIV(O)]2+-(HOTf)2 have been unified for the first time as the same reaction pathway via outer-sphere electron transfer, followed by the fast bond-forming step, which exhibits the singly unified electron-transfer driving force dependence of the rate constants as outer-sphere electron-transfer reactions. In the case of the epoxidation of cis-stilbene by [(N4Py)MnIV(O)]2+-(HOTf)2, the isomerization of cis-stilbene radical cation to trans-stilbene radical cation occurs after outer-sphere electron transfer from cis-stilbene to [(N4Py)MnIV(O)]2+-(HOTf)2 to yield trans-stilbene oxide selectively, which is also taken as evidence for the occurrence of electron transfer in the acid-catalyzed epoxidation.
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Unified Mechanism of Oxygen Atom Transfer and Hydrogen Atom Transfer Reactions with a Triflic Acid-Bound Nonheme Manganese(IV)–Oxo Complex via Outer-Sphere Electron Transfer
2019Co-Authors: Yongmin Lee, Wonwoo Nam, Kei Ohkubo, Surin Kim, Kyung-ha Kim, Shunichi FukuzumiAbstract:Outer-sphere electron transfer from styrene, Thioanisole, and toluene derivatives to a triflic acid (HOTf)-bound nonheme Mn(IV)–oxo complex, [(N4Py)MnIV(O)]2+–(HOTf)2 (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), has been shown to be the rate-determining step of different types of redox reactions such as epoxidation, sulfoxidation, and hydroxylation of styrene, Thioanisole, and toluene derivatives, respectively, by [(N4Py)MnIV(O)]2+–(HOTf)2. The rate constants of HOTf-promoted epoxidation of all styrene derivatives with [(N4Py)MnIV(O)]2+ and electron transfer from electron donors to [(N4Py)MnV(O)]2+ exhibit a remarkably unified correlation with the driving force of outer-sphere electron transfer in light of the Marcus theory of electron transfer. The same electron-transfer driving force dependence is observed in the oxygen atom transfer from [(N4Py)MnIV(O)]2+–(HOTf)2 to Thioanisole derivatives as well as in the hydrogen atom transfer from toluene derivatives to [(N4Py)MnIV(O)]2+–(HOTf)2. Thus, mechanisms of oxygen atom transfer (epoxidation and sulfoxidation) reactions of styrene and Thioanisole derivatives and hydrogen atom transfer (hydroxylation) reactions of toluene derivatives by [(N4Py)MnIV(O)]2+–(HOTf)2 have been unified for the first time as the same reaction pathway via outer-sphere electron transfer, followed by the fast bond-forming step, which exhibits the singly unified electron-transfer driving force dependence of the rate constants as outer-sphere electron-transfer reactions. In the case of the epoxidation of cis-stilbene by [(N4Py)MnIV(O)]2+–(HOTf)2, the isomerization of cis-stilbene radical cation to trans-stilbene radical cation occurs after outer-sphere electron transfer from cis-stilbene to [(N4Py)MnIV(O)]2+–(HOTf)2 to yield trans-stilbene oxide selectively, which is also taken as evidence for the occurrence of electron transfer in the acid-catalyzed epoxidation
Yongmin Lee - One of the best experts on this subject based on the ideXlab platform.
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unified mechanism of oxygen atom transfer and hydrogen atom transfer reactions with a triflic acid bound nonheme manganese iv oxo complex via outer sphere electron transfer
Journal of the American Chemical Society, 2019Co-Authors: Yongmin Lee, Shunichi Fukuzumi, Wonwoo Nam, Kei Ohkubo, Surin Kim, Kyung-ha KimAbstract:Outer-sphere electron transfer from styrene, Thioanisole, and toluene derivatives to a triflic acid (HOTf)-bound nonheme Mn(IV)-oxo complex, [(N4Py)MnIV(O)]2+-(HOTf)2 (N4Py = N, N-bis(2-pyridylmethyl)- N-bis(2-pyridyl)methylamine), has been shown to be the rate-determining step of different types of redox reactions such as epoxidation, sulfoxidation, and hydroxylation of styrene, Thioanisole, and toluene derivatives, respectively, by [(N4Py)MnIV(O)]2+-(HOTf)2. The rate constants of HOTf-promoted epoxidation of all styrene derivatives with [(N4Py)MnIV(O)]2+ and electron transfer from electron donors to [(N4Py)MnV(O)]2+ exhibit a remarkably unified correlation with the driving force of outer-sphere electron transfer in light of the Marcus theory of electron transfer. The same electron-transfer driving force dependence is observed in the oxygen atom transfer from [(N4Py)MnIV(O)]2+-(HOTf)2 to Thioanisole derivatives as well as in the hydrogen atom transfer from toluene derivatives to [(N4Py)MnIV(O)]2+-(HOTf)2. Thus, mechanisms of oxygen atom transfer (epoxidation and sulfoxidation) reactions of styrene and Thioanisole derivatives and hydrogen atom transfer (hydroxylation) reactions of toluene derivatives by [(N4Py)MnIV(O)]2+-(HOTf)2 have been unified for the first time as the same reaction pathway via outer-sphere electron transfer, followed by the fast bond-forming step, which exhibits the singly unified electron-transfer driving force dependence of the rate constants as outer-sphere electron-transfer reactions. In the case of the epoxidation of cis-stilbene by [(N4Py)MnIV(O)]2+-(HOTf)2, the isomerization of cis-stilbene radical cation to trans-stilbene radical cation occurs after outer-sphere electron transfer from cis-stilbene to [(N4Py)MnIV(O)]2+-(HOTf)2 to yield trans-stilbene oxide selectively, which is also taken as evidence for the occurrence of electron transfer in the acid-catalyzed epoxidation.
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Unified Mechanism of Oxygen Atom Transfer and Hydrogen Atom Transfer Reactions with a Triflic Acid-Bound Nonheme Manganese(IV)–Oxo Complex via Outer-Sphere Electron Transfer
2019Co-Authors: Yongmin Lee, Wonwoo Nam, Kei Ohkubo, Surin Kim, Kyung-ha Kim, Shunichi FukuzumiAbstract:Outer-sphere electron transfer from styrene, Thioanisole, and toluene derivatives to a triflic acid (HOTf)-bound nonheme Mn(IV)–oxo complex, [(N4Py)MnIV(O)]2+–(HOTf)2 (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), has been shown to be the rate-determining step of different types of redox reactions such as epoxidation, sulfoxidation, and hydroxylation of styrene, Thioanisole, and toluene derivatives, respectively, by [(N4Py)MnIV(O)]2+–(HOTf)2. The rate constants of HOTf-promoted epoxidation of all styrene derivatives with [(N4Py)MnIV(O)]2+ and electron transfer from electron donors to [(N4Py)MnV(O)]2+ exhibit a remarkably unified correlation with the driving force of outer-sphere electron transfer in light of the Marcus theory of electron transfer. The same electron-transfer driving force dependence is observed in the oxygen atom transfer from [(N4Py)MnIV(O)]2+–(HOTf)2 to Thioanisole derivatives as well as in the hydrogen atom transfer from toluene derivatives to [(N4Py)MnIV(O)]2+–(HOTf)2. Thus, mechanisms of oxygen atom transfer (epoxidation and sulfoxidation) reactions of styrene and Thioanisole derivatives and hydrogen atom transfer (hydroxylation) reactions of toluene derivatives by [(N4Py)MnIV(O)]2+–(HOTf)2 have been unified for the first time as the same reaction pathway via outer-sphere electron transfer, followed by the fast bond-forming step, which exhibits the singly unified electron-transfer driving force dependence of the rate constants as outer-sphere electron-transfer reactions. In the case of the epoxidation of cis-stilbene by [(N4Py)MnIV(O)]2+–(HOTf)2, the isomerization of cis-stilbene radical cation to trans-stilbene radical cation occurs after outer-sphere electron transfer from cis-stilbene to [(N4Py)MnIV(O)]2+–(HOTf)2 to yield trans-stilbene oxide selectively, which is also taken as evidence for the occurrence of electron transfer in the acid-catalyzed epoxidation
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unified view of oxidative c h bond cleavage and sulfoxidation by a nonheme iron iv oxo complex via lewis acid promoted electron transfer
Inorganic Chemistry, 2014Co-Authors: Jiyun Park, Wonwoo Nam, Yuma Morimoto, Yongmin Lee, Shunichi FukuzumiAbstract:Oxidative C–H bond cleavage of toluene derivatives and sulfoxidation of Thioanisole derivatives by a nonheme iron(IV)–oxo complex, [(N4Py)FeIV(O)]2+ (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), were remarkably enhanced by the presence of triflic acid (HOTf) and Sc(OTf)3 in acetonitrile at 298 K. All the logarithms of the observed second-order rate constants of both the oxidative C–H bond cleavage and sulfoxidation reactions exhibit remarkably unified correlations with the driving forces of proton-coupled electron transfer (PCET) and metal ion-coupled electron transfer (MCET) in light of the Marcus theory of electron transfer when the differences in the formation constants of precursor complexes between PCET and MCET were taken into account, respectively. Thus, the mechanisms of both the oxidative C–H bond cleavage of toluene derivatives and sulfoxidation of Thioanisole derivatives by [(N4Py)FeIV(O)]2+ in the presence of HOTf and Sc(OTf)3 have been unified as the rate-determining electron...
