As DNA cleavage agent, a new diiron（Ⅲ） complex （Fe2Lb）, in which a DNA-intercalator （pyrene） is covalently linked to a diferric moiety, has been synthesized and characterized. The DNA-binding property and DNA c...As DNA cleavage agent, a new diiron（Ⅲ） complex （Fe2Lb）, in which a DNA-intercalator （pyrene） is covalently linked to a diferric moiety, has been synthesized and characterized. The DNA-binding property and DNA cleavage activity of the complex have also been investigated.展开更多
The activation of dioxygen and incorporation into hydrocarbons have been achieved under mild conditions by a methane monooxygenase (MMO)-like system using a dinuclear iron complex [Fe2Dhist(OAc)2] BPh4 ·3H2O as t...The activation of dioxygen and incorporation into hydrocarbons have been achieved under mild conditions by a methane monooxygenase (MMO)-like system using a dinuclear iron complex [Fe2Dhist(OAc)2] BPh4 ·3H2O as the model complex, zinc powder as the electron donor, HOAc as the proton source and methylviologen as the electron transfer agent. The results show that styrene is oxygenated predominantly to styrene oxide (1 396 mol/100 mol of the Fe2 complex), benzaldehyde (16160) and acetophenone (986), and cyclohexane to cyclohexanol (9370) and cyclo-hexanone (2670). EPR studies indicate that the hypervalent ironoxo spiecs FeⅣFeⅣ=O, derived from FeⅢFeⅢ core via reduction, O2-binding and protonation, is the active intermediate which inserts the activated oxygen atom into C=C or C-H bond giving each product. The system closely resembles MMO and its close relative hemerythrin in the aspects of reaction phenomena, EPR characteristics and product distributions. The Mn2 analog cmplex、 Fe-Zn het-erodinuclear complex and mononuclear iron complex show no catalytic activity, indicating that dinuclear iron core is in-despansable to catalytic activity.展开更多
A ( μ oxo)( μ CO 3)diiron(Ⅲ) complex of tri(2 pyridylmethyl)amine(TPA), [Fe 2L 2( μ O) ( μ CO 3)] (ClO 4) 2·MeOH·EtOH·H 2O], was synthesized and characterized, where L represents TPA. This complex ...A ( μ oxo)( μ CO 3)diiron(Ⅲ) complex of tri(2 pyridylmethyl)amine(TPA), [Fe 2L 2( μ O) ( μ CO 3)] (ClO 4) 2·MeOH·EtOH·H 2O], was synthesized and characterized, where L represents TPA. This complex crystallizes in the monoclinic space group P2 1/c with a =1.181 0(3) nm, b =3.728 1(8) nm, c = 1.377 0(3) nm , β =115.393(3)°, V =5.477(2) nm 3, Z =4. R 1=0.084 9 and wR 2=0.196 2. The UV Vis spectra of this compound show multiply absorption bands in 200-800 nm range, which are similar to that of N - 3 coordinated met hemerythrin. , was synthesized and characterized, where L represents TPA. This complex crystallizes in the monoclinic space group P2 1/c with a =1.181 0(3) nm, b =3.728 1(8) nm, c = 1.377 0(3) nm , β =115.393(3)°, V =5.477(2) nm 3, Z =4. R 1=0.084 9 and wR 2=0.196 2. The UV Vis spectra of this compound show multiply absorption bands in 200-800 nm range, which are similar to that of N - 3 coordinated met hemerythrin.展开更多
Photocatalytic reduction of CO2 to CO is a promising approach for storing solar energy in chemicals and mitigating the greenhouse effect of CO2.Our recent studies revealed that[(μ-bdt)Fe2(CO)6](1,bdt=benzene-1,2-dith...Photocatalytic reduction of CO2 to CO is a promising approach for storing solar energy in chemicals and mitigating the greenhouse effect of CO2.Our recent studies revealed that[(μ-bdt)Fe2(CO)6](1,bdt=benzene-1,2-dithiolato),a[FeFe]-hydrogenase model with a rigid and conjugate S-to-S bridge,was catalytically active for the selective photochemical reduction of CO2 to CO,while its analogous complex[(μ-edt)Fe2(CO)6](2,edt=ethane-1,2-dithiolato)was inactive.In this study,it was found that the turnover number of 1 for CO evolution reached 710 for the 1/[Ru(bpy)3]2+/BIH(BIH=1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]-imidazole)system under optimal conditions over 4.5 h of visible-light irradiation,with a turnover frequency of 7.12 min−1 in the first hour,a high selectivity of 97%for CO,and an internal quantum yield of 2.8%.Interestingly,the catalytic selectivity of 1 can be adjusted and even completely switched in a facile manner between the photochemical reductions of CO2 to CO and of protons to H2 simply by adding different amounts of triethanolamine to the catalytic system.The electron transfer in the photocatalytic system was studied by steady-state fluorescence and transient absorption spectroscopy,and a plausible mechanism for the photocatalytic reaction was proposed.展开更多
The synthesis and structure of [Fe(Phen)3][(μ-oxo)Fe2Cl6]稤MF are reported. The crystal data for the compound: monoclinic, P2l /c,a =15.491(1),b = 13.217(1),c = 20.748(2)牛?= 93.83(3),V = 4239(2)?,Z = 4,Dc = 1.562g/c...The synthesis and structure of [Fe(Phen)3][(μ-oxo)Fe2Cl6]稤MF are reported. The crystal data for the compound: monoclinic, P2l /c,a =15.491(1),b = 13.217(1),c = 20.748(2)牛?= 93.83(3),V = 4239(2)?,Z = 4,Dc = 1.562g/cm3,μ(MoK)=1.44 mm-1,F(000)= 2040.0, (C39H31Cl6Fe3N7O2) and Mr = 1009.96. X-ray crystallographic studies reveal that the title compound contains complexes of [Fe(Phen)3]2+ and [Fe2(μ-oxo)Cl6]2- which consists of two [FeCl3] fragments connected by an oxo bridge,with the bond distances of Fe(3)O(1) 1.744(4) and Fe(2)O(1) 1.754(4)牛琣nd a bond angle Fe(2)O(1)Fe(3) of 162.9(3). In the [Fe2(μ-oxo)Cl6]2- complex, the two iron (Ⅲ) centres exhibit tetrahedral coordination, with the distorted tetrahedra formed by three Cl atoms and an oxo bridge. The bond lengths to the donor atoms lie in the range 2.211(1)～2.226(1)?for FeCl, and the non-bonded Fe…Fe distance is 3.459?展开更多
Iron sites in both nitrogenase enzymes and chemical catalysts for N_(2) fixation are typically at constrained distances and angles.Herein,we report a one-electron reduction reaction realized by constrained diiron dini...Iron sites in both nitrogenase enzymes and chemical catalysts for N_(2) fixation are typically at constrained distances and angles.Herein,we report a one-electron reduction reaction realized by constrained diiron dinitrogen cores.Using the semicircular bis(β-diketiminate)ligand,a series of diiron dinitrogen complexes were synthesized,in which the N_(2) groups were allowed to bind with Fe-Ct_(N2)-Fe angles ranging from 154°to 158°(Ct_(N2)=centroid of N_(2)).One-electron reduction of complex 2a[LFe(μ-N_(2))Fe(Et_(2)O)]gave dimer product 3a[LFe(μ-N_(2))FeK]_(2)(μ-N_(2))or monomer 3b[LFe(μ-N_(2))Fe(DMAP)K].Based on superconducting quantum interference device measurements and density functional theory calculations,2a,3a,and 3b exhibited ground spin states of S=3,S=5,and S=5/2,respectively.In addition,complex 3 underwent N_(2)derivatization via a silylation pathway followed by an acidic cleavage to yield N_(2)H_(4)as the product.展开更多
The title compound [Ni(bipy)3][(-oxo)Fe2Cl6] (bipy = 2, 2?bispyridine) was synthesized and its crystal structure was determined by X-ray diffraction method. It crystallizes in monoclinic, space group P2l/c with unit c...The title compound [Ni(bipy)3][(-oxo)Fe2Cl6] (bipy = 2, 2?bispyridine) was synthesized and its crystal structure was determined by X-ray diffraction method. It crystallizes in monoclinic, space group P2l/c with unit cell parameters: a = 9.7085(7),b = 26.409(2), c = 14.014(1) ,?= 100.237(3), V = 3535.9(2) 3,Z = 4,C30H24Cl6Fe2N6NiO,Mr = 867.66, Dc = 1.630 g/cm3,F(000) = 1744, (MoK? = 1.824 mm-1, the final R = 0.0394 and wR = 0.0475 for 2750 observed reflections with I ≥ 2(I). The title compound contains cation of [Ni(bipy)3]2+ and anion of [(-oxo)Fe2Cl6] 2- which consists of two [FeCl3] fragments connected by an oxo bridge with the bond distances of Fe(2)O(1) 1.752(2) and Fe(1)O(1) 1.763(2) , and the bond angle of Fe(2)O(1)Fe(1) 148.6(2)? In the [Fe2(-oxo)Cl6]2- complex, the two iron(Ⅲ) centers exhibit a tetrahedral coordination with the distorted tetrahedron formed by three Cl atoms and one oxo bridge.展开更多
The dinuclear complex of [Fe2L{O2P(OPh)2}](ClO4)2· Et2O(1) (where L represents the dinucleating ligand N-Et-HPTB, anion of N, N, N’, N’-tetrakis (N-ethyl-2-benzimidazolyemethyl)2-hydroxy-1, 3-diamino-propane) h...The dinuclear complex of [Fe2L{O2P(OPh)2}](ClO4)2· Et2O(1) (where L represents the dinucleating ligand N-Et-HPTB, anion of N, N, N’, N’-tetrakis (N-ethyl-2-benzimidazolyemethyl)2-hydroxy-1, 3-diamino-propane) has been synthesized and crystallizes in the triclinic space group P1 with cell constants a = 1.526(3) nm, b = 1.259 8(3) nm, c = 1.563 0(3)° nm, α = 94.41(3)°, β = 115.31(3)°, γ = 99.90(3)°, V = 3.267(1) nm3, z = 2, R = 0.084 7 and Rw = 0.177 8. The Fe(II) sites are bridged by an alkoxide of the dinucleating ligand and a phosphate, affording a diiron core with an Fe-μ-O-Fe angle of 131.20(3)° and an Fe-Fe distance of 0.364 9 nm. Both Fe(II) centers have trigonal bipyramidal geometry. Dioxygen adduct (1/O2) forms upon exposure of the diferrous complex to O2 at low temperature (?60°C). The 1/O2 adduct is stable at ? 60°C but decomposes upon warming. The adduct exhibits visible absorption maximum near 606 nm and resonance Raman features at 478 cm-1 (γFe-O) and 897 cm-1 (γO-O), and the latter is the characteristic of a μ-1,2-peroxo species, indicating that dioxygen adducts can serve as models for the putative oxygenated intermediate of some non-heme diiron-oxo proteins.展开更多
文摘As DNA cleavage agent, a new diiron（Ⅲ） complex （Fe2Lb）, in which a DNA-intercalator （pyrene） is covalently linked to a diferric moiety, has been synthesized and characterized. The DNA-binding property and DNA cleavage activity of the complex have also been investigated.
文摘The activation of dioxygen and incorporation into hydrocarbons have been achieved under mild conditions by a methane monooxygenase (MMO)-like system using a dinuclear iron complex [Fe2Dhist(OAc)2] BPh4 ·3H2O as the model complex, zinc powder as the electron donor, HOAc as the proton source and methylviologen as the electron transfer agent. The results show that styrene is oxygenated predominantly to styrene oxide (1 396 mol/100 mol of the Fe2 complex), benzaldehyde (16160) and acetophenone (986), and cyclohexane to cyclohexanol (9370) and cyclo-hexanone (2670). EPR studies indicate that the hypervalent ironoxo spiecs FeⅣFeⅣ=O, derived from FeⅢFeⅢ core via reduction, O2-binding and protonation, is the active intermediate which inserts the activated oxygen atom into C=C or C-H bond giving each product. The system closely resembles MMO and its close relative hemerythrin in the aspects of reaction phenomena, EPR characteristics and product distributions. The Mn2 analog cmplex、 Fe-Zn het-erodinuclear complex and mononuclear iron complex show no catalytic activity, indicating that dinuclear iron core is in-despansable to catalytic activity.
文摘A ( μ oxo)( μ CO 3)diiron(Ⅲ) complex of tri(2 pyridylmethyl)amine(TPA), [Fe 2L 2( μ O) ( μ CO 3)] (ClO 4) 2·MeOH·EtOH·H 2O], was synthesized and characterized, where L represents TPA. This complex crystallizes in the monoclinic space group P2 1/c with a =1.181 0(3) nm, b =3.728 1(8) nm, c = 1.377 0(3) nm , β =115.393(3)°, V =5.477(2) nm 3, Z =4. R 1=0.084 9 and wR 2=0.196 2. The UV Vis spectra of this compound show multiply absorption bands in 200-800 nm range, which are similar to that of N - 3 coordinated met hemerythrin. , was synthesized and characterized, where L represents TPA. This complex crystallizes in the monoclinic space group P2 1/c with a =1.181 0(3) nm, b =3.728 1(8) nm, c = 1.377 0(3) nm , β =115.393(3)°, V =5.477(2) nm 3, Z =4. R 1=0.084 9 and wR 2=0.196 2. The UV Vis spectra of this compound show multiply absorption bands in 200-800 nm range, which are similar to that of N - 3 coordinated met hemerythrin.
文摘Photocatalytic reduction of CO2 to CO is a promising approach for storing solar energy in chemicals and mitigating the greenhouse effect of CO2.Our recent studies revealed that[(μ-bdt)Fe2(CO)6](1,bdt=benzene-1,2-dithiolato),a[FeFe]-hydrogenase model with a rigid and conjugate S-to-S bridge,was catalytically active for the selective photochemical reduction of CO2 to CO,while its analogous complex[(μ-edt)Fe2(CO)6](2,edt=ethane-1,2-dithiolato)was inactive.In this study,it was found that the turnover number of 1 for CO evolution reached 710 for the 1/[Ru(bpy)3]2+/BIH(BIH=1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]-imidazole)system under optimal conditions over 4.5 h of visible-light irradiation,with a turnover frequency of 7.12 min−1 in the first hour,a high selectivity of 97%for CO,and an internal quantum yield of 2.8%.Interestingly,the catalytic selectivity of 1 can be adjusted and even completely switched in a facile manner between the photochemical reductions of CO2 to CO and of protons to H2 simply by adding different amounts of triethanolamine to the catalytic system.The electron transfer in the photocatalytic system was studied by steady-state fluorescence and transient absorption spectroscopy,and a plausible mechanism for the photocatalytic reaction was proposed.
基金Supported by the foundation of Education Committee of Fujian Province (JB01045)
文摘The synthesis and structure of [Fe(Phen)3][(μ-oxo)Fe2Cl6]稤MF are reported. The crystal data for the compound: monoclinic, P2l /c,a =15.491(1),b = 13.217(1),c = 20.748(2)牛?= 93.83(3),V = 4239(2)?,Z = 4,Dc = 1.562g/cm3,μ(MoK)=1.44 mm-1,F(000)= 2040.0, (C39H31Cl6Fe3N7O2) and Mr = 1009.96. X-ray crystallographic studies reveal that the title compound contains complexes of [Fe(Phen)3]2+ and [Fe2(μ-oxo)Cl6]2- which consists of two [FeCl3] fragments connected by an oxo bridge,with the bond distances of Fe(3)O(1) 1.744(4) and Fe(2)O(1) 1.754(4)牛琣nd a bond angle Fe(2)O(1)Fe(3) of 162.9(3). In the [Fe2(μ-oxo)Cl6]2- complex, the two iron (Ⅲ) centres exhibit tetrahedral coordination, with the distorted tetrahedra formed by three Cl atoms and an oxo bridge. The bond lengths to the donor atoms lie in the range 2.211(1)～2.226(1)?for FeCl, and the non-bonded Fe…Fe distance is 3.459?
基金supported by National Natural Science Foundation of China(grant nos.21988101,22201013,92161204)China Postdoctoral Science Foundation(grant no.2020M670016)Beijing Natural Science Foundation(grant no.2222008).
文摘Iron sites in both nitrogenase enzymes and chemical catalysts for N_(2) fixation are typically at constrained distances and angles.Herein,we report a one-electron reduction reaction realized by constrained diiron dinitrogen cores.Using the semicircular bis(β-diketiminate)ligand,a series of diiron dinitrogen complexes were synthesized,in which the N_(2) groups were allowed to bind with Fe-Ct_(N2)-Fe angles ranging from 154°to 158°(Ct_(N2)=centroid of N_(2)).One-electron reduction of complex 2a[LFe(μ-N_(2))Fe(Et_(2)O)]gave dimer product 3a[LFe(μ-N_(2))FeK]_(2)(μ-N_(2))or monomer 3b[LFe(μ-N_(2))Fe(DMAP)K].Based on superconducting quantum interference device measurements and density functional theory calculations,2a,3a,and 3b exhibited ground spin states of S=3,S=5,and S=5/2,respectively.In addition,complex 3 underwent N_(2)derivatization via a silylation pathway followed by an acidic cleavage to yield N_(2)H_(4)as the product.
基金Supported by the foundation of Education Committee of Fujian Province (JB01045)
文摘The title compound [Ni(bipy)3][(-oxo)Fe2Cl6] (bipy = 2, 2?bispyridine) was synthesized and its crystal structure was determined by X-ray diffraction method. It crystallizes in monoclinic, space group P2l/c with unit cell parameters: a = 9.7085(7),b = 26.409(2), c = 14.014(1) ,?= 100.237(3), V = 3535.9(2) 3,Z = 4,C30H24Cl6Fe2N6NiO,Mr = 867.66, Dc = 1.630 g/cm3,F(000) = 1744, (MoK? = 1.824 mm-1, the final R = 0.0394 and wR = 0.0475 for 2750 observed reflections with I ≥ 2(I). The title compound contains cation of [Ni(bipy)3]2+ and anion of [(-oxo)Fe2Cl6] 2- which consists of two [FeCl3] fragments connected by an oxo bridge with the bond distances of Fe(2)O(1) 1.752(2) and Fe(1)O(1) 1.763(2) , and the bond angle of Fe(2)O(1)Fe(1) 148.6(2)? In the [Fe2(-oxo)Cl6]2- complex, the two iron(Ⅲ) centers exhibit a tetrahedral coordination with the distorted tetrahedron formed by three Cl atoms and one oxo bridge.
文摘The dinuclear complex of [Fe2L{O2P(OPh)2}](ClO4)2· Et2O(1) (where L represents the dinucleating ligand N-Et-HPTB, anion of N, N, N’, N’-tetrakis (N-ethyl-2-benzimidazolyemethyl)2-hydroxy-1, 3-diamino-propane) has been synthesized and crystallizes in the triclinic space group P1 with cell constants a = 1.526(3) nm, b = 1.259 8(3) nm, c = 1.563 0(3)° nm, α = 94.41(3)°, β = 115.31(3)°, γ = 99.90(3)°, V = 3.267(1) nm3, z = 2, R = 0.084 7 and Rw = 0.177 8. The Fe(II) sites are bridged by an alkoxide of the dinucleating ligand and a phosphate, affording a diiron core with an Fe-μ-O-Fe angle of 131.20(3)° and an Fe-Fe distance of 0.364 9 nm. Both Fe(II) centers have trigonal bipyramidal geometry. Dioxygen adduct (1/O2) forms upon exposure of the diferrous complex to O2 at low temperature (?60°C). The 1/O2 adduct is stable at ? 60°C but decomposes upon warming. The adduct exhibits visible absorption maximum near 606 nm and resonance Raman features at 478 cm-1 (γFe-O) and 897 cm-1 (γO-O), and the latter is the characteristic of a μ-1,2-peroxo species, indicating that dioxygen adducts can serve as models for the putative oxygenated intermediate of some non-heme diiron-oxo proteins.
