The oxygenation constants of transition-metal complexes with benzoin Schiff bases were measured and these complexes were first employed as models for mimicking monooxygenase in catalytic epoxidation of styrene. The hi...The oxygenation constants of transition-metal complexes with benzoin Schiff bases were measured and these complexes were first employed as models for mimicking monooxygenase in catalytic epoxidation of styrene. The highest conversion and selectivity were up to 39.6% and 100% respectively at ambient temperature and pressure. The effects of structures of the bridge group R in the ligands on the dioxygen affinities and catalytic activities to epoxidize styrene were also investigated.展开更多
The dioxygen affinities and biomimetic catalytic performance of transition-metal complexes with (15-crown-5) salophen and its substituted derivatives Mere examined. The oxygenation constants of Co(II) complexes with c...The dioxygen affinities and biomimetic catalytic performance of transition-metal complexes with (15-crown-5) salophen and its substituted derivatives Mere examined. The oxygenation constants of Co(II) complexes with crowned bis-Schiff bases were measured and their Mn(III) complexes were employed as models to mimic monooxygenase in catalytic epoxidation of styrene. The highest conversion and selectivity were up to 57.2% and 100% respectively at ambient temperature and pressure. The effects of crown ether ring and substituents R on the dioxygen affinities and catalytic activities were also investigated through comparing with the uncrowned analogues.展开更多
The oxygenation constants （Ko2） of cobalt（Ⅱ） hydroxamates （CoL^1 2-CoL^3 2） with benzo-15-crown-5 （B15C5） pendants were measured over the range of -5 to ＋20 ℃, and the values of thermodynamic parameters （...The oxygenation constants （Ko2） of cobalt（Ⅱ） hydroxamates （CoL^1 2-CoL^3 2） with benzo-15-crown-5 （B15C5） pendants were measured over the range of -5 to ＋20 ℃, and the values of thermodynamic parameters （ΔH^0 and ΔS^0） were calculated based on these （Ko2） values, Meanwhile, these crowned complexes were employed to the oxidation for p-xylene to p-toluic acid with air at 110Δ under normal atmospheric pressure. The effects of B15C5 pendant and the length of chain bonded to B15C5 in these complexes on the O2-binding capabilities and oxidation for p-xylene were investigated with the comparison of crown-free analogues CoL^4 2.展开更多
The dioxygen affinities and catalytic epoxidation performance of transition-metal hydroxamates were investigated for the first time. The effects of substituents on these properties were also discussed in the paper.
The oxygenation of cobalt (II) hydroxamates (CoL2) and its catalytic performance in oxidation of p-xylene to p-toluic acid (PTA) were examined. The effects of X and Y bonded to hydroxamate group on dioxygen affinitie...The oxygenation of cobalt (II) hydroxamates (CoL2) and its catalytic performance in oxidation of p-xylene to p-toluic acid (PTA) were examined. The effects of X and Y bonded to hydroxamate group on dioxygen affinities and catalytic oxidation performance were also investigated.展开更多
The oxygenation constants and thermodynamic parameter （△H°, △S°） of a series of novel Co （Ⅱ） complexes with phenol ether bridged dihydroxamic acids CoL^1-CoL^6 were measured, their catalytic performan...The oxygenation constants and thermodynamic parameter （△H°, △S°） of a series of novel Co （Ⅱ） complexes with phenol ether bridged dihydroxamic acids CoL^1-CoL^6 were measured, their catalytic performance in oxidation of p-xylene to p-toluic acid （PTA） were examined. The modulation of O2-binding capabilities and catalytic oxidation activities by X （X = Cl, OCH3） and Y （Y = H, CH3, Cl） groups bonded to the aromatic rings of the Co （Ⅱ） complexes were investigated.展开更多
The oxygenation constants and thermodynamic parameter (ΔHo, ΔSo) of Co (II) complexes with unsymmetrical bis-Schiff baeses were measured and their Mn(III) complexes as models of mimicking monooxygenase were employed...The oxygenation constants and thermodynamic parameter (ΔHo, ΔSo) of Co (II) complexes with unsymmetrical bis-Schiff baeses were measured and their Mn(III) complexes as models of mimicking monooxygenase were employed to catalyze epoxidation of styrene. The effect of substituent R in a salicylidene of ML1~ML4 [ M = Co (II), Mn (III)Cl ] on the dioxygen affinities and biomimetic catalytic oxidation performance were also investigated. Among them, the MnL4Cl containing a pendant benzoaza crown ether ring showed highest conversion and selectiviy up to 54.9% and 96.9% respectively.展开更多
Novel Co（Ⅱ） complexes with dihydroxamic acids functionalized N-pivot lariat ether CoL^1-CoL^4 were synthesized and characterized.Their oxygenation constants（ln K_（O2）） and thermodynamic parameters（△H°,△...Novel Co（Ⅱ） complexes with dihydroxamic acids functionalized N-pivot lariat ether CoL^1-CoL^4 were synthesized and characterized.Their oxygenation constants（ln K_（O2）） and thermodynamic parameters（△H°,△S°） were measured.And their catalytic performance in oxidation of p-xylene to p-toluic acid（PTA） was investigated.The enhancement of O_2-binding and catalytic oxidation activity by the oxa aza crown ether ring of the cobalt complexes were discussed.展开更多
文摘The oxygenation constants of transition-metal complexes with benzoin Schiff bases were measured and these complexes were first employed as models for mimicking monooxygenase in catalytic epoxidation of styrene. The highest conversion and selectivity were up to 39.6% and 100% respectively at ambient temperature and pressure. The effects of structures of the bridge group R in the ligands on the dioxygen affinities and catalytic activities to epoxidize styrene were also investigated.
基金the National Natural Science Foundation of China.
文摘The dioxygen affinities and biomimetic catalytic performance of transition-metal complexes with (15-crown-5) salophen and its substituted derivatives Mere examined. The oxygenation constants of Co(II) complexes with crowned bis-Schiff bases were measured and their Mn(III) complexes were employed as models to mimic monooxygenase in catalytic epoxidation of styrene. The highest conversion and selectivity were up to 57.2% and 100% respectively at ambient temperature and pressure. The effects of crown ether ring and substituents R on the dioxygen affinities and catalytic activities were also investigated through comparing with the uncrowned analogues.
基金The authors gratefully acknowledge the grants from the National Natural Science Foundation of China(No.20072025)Education 0ffice Foundation of Sichuan Province(No.2005C012)Sichuan Provincial Department of Science&Technology(No.2006J13-143)in support of this work.
文摘The oxygenation constants （Ko2） of cobalt（Ⅱ） hydroxamates （CoL^1 2-CoL^3 2） with benzo-15-crown-5 （B15C5） pendants were measured over the range of -5 to ＋20 ℃, and the values of thermodynamic parameters （ΔH^0 and ΔS^0） were calculated based on these （Ko2） values, Meanwhile, these crowned complexes were employed to the oxidation for p-xylene to p-toluic acid with air at 110Δ under normal atmospheric pressure. The effects of B15C5 pendant and the length of chain bonded to B15C5 in these complexes on the O2-binding capabilities and oxidation for p-xylene were investigated with the comparison of crown-free analogues CoL^4 2.
文摘The dioxygen affinities and catalytic epoxidation performance of transition-metal hydroxamates were investigated for the first time. The effects of substituents on these properties were also discussed in the paper.
基金This work is supported by the National Natural Science Foundation of China(Grant No.2007205).
文摘The oxygenation of cobalt (II) hydroxamates (CoL2) and its catalytic performance in oxidation of p-xylene to p-toluic acid (PTA) were examined. The effects of X and Y bonded to hydroxamate group on dioxygen affinities and catalytic oxidation performance were also investigated.
基金supported by the National Natural Science Foundation of China(No.2007205).
文摘The oxygenation constants and thermodynamic parameter （△H°, △S°） of a series of novel Co （Ⅱ） complexes with phenol ether bridged dihydroxamic acids CoL^1-CoL^6 were measured, their catalytic performance in oxidation of p-xylene to p-toluic acid （PTA） were examined. The modulation of O2-binding capabilities and catalytic oxidation activities by X （X = Cl, OCH3） and Y （Y = H, CH3, Cl） groups bonded to the aromatic rings of the Co （Ⅱ） complexes were investigated.
文摘The oxygenation constants and thermodynamic parameter (ΔHo, ΔSo) of Co (II) complexes with unsymmetrical bis-Schiff baeses were measured and their Mn(III) complexes as models of mimicking monooxygenase were employed to catalyze epoxidation of styrene. The effect of substituent R in a salicylidene of ML1~ML4 [ M = Co (II), Mn (III)Cl ] on the dioxygen affinities and biomimetic catalytic oxidation performance were also investigated. Among them, the MnL4Cl containing a pendant benzoaza crown ether ring showed highest conversion and selectiviy up to 54.9% and 96.9% respectively.
基金supported by Chongqing Education Commission(No.KJ1400632)
文摘Novel Co（Ⅱ） complexes with dihydroxamic acids functionalized N-pivot lariat ether CoL^1-CoL^4 were synthesized and characterized.Their oxygenation constants（ln K_（O2）） and thermodynamic parameters（△H°,△S°） were measured.And their catalytic performance in oxidation of p-xylene to p-toluic acid（PTA） was investigated.The enhancement of O_2-binding and catalytic oxidation activity by the oxa aza crown ether ring of the cobalt complexes were discussed.
