Three cobalt complexes bearing tunable,redox-active bipyridyl N-heterocyclic carbene(NHC)-based ligands have been studied for electrocatalytic hydrogen evolution from aqueous solutions.The effect of structural modific...Three cobalt complexes bearing tunable,redox-active bipyridyl N-heterocyclic carbene(NHC)-based ligands have been studied for electrocatalytic hydrogen evolution from aqueous solutions.The effect of structural modifications to the ligand framework is investigated across the catalyst series,which includes a non-macrocyclic derivative(1-Co)and 16-(2-Co)and 15-(3-Co)membered macrocycles.A structure-activity relationship is demonstrated,in which the macrocyclic complexes have greater activity compared to their non-macrocyclic counterpart with the most rigid catalyst,supported by the 15-membered macrocycle,performing best overall.Indeed,3-Co catalyzes H2 evolution from aqueous pH 4 acetate buffer with a Faradaic efficiency of 97%at a low overpotential of 330 mV.Mechanistic studies are consistent with formation of a cobalt-hydride species that is subsequently protonated to evolve H2 via a heterolytic pathway.展开更多
The catalytic properties of a series of cobalt complexes containing bidenated nitrogen ligand for displacement reaction of trialkylaluminum with ethylene is reported. Effect of different reaction time, temperature an...The catalytic properties of a series of cobalt complexes containing bidenated nitrogen ligand for displacement reaction of trialkylaluminum with ethylene is reported. Effect of different reaction time, temperature and cobalt complexes containing different ligand on catalyst performance has been investigated.展开更多
The transition metal-catalyzed acceptorless dehydrogenative coupling of alcohols and amines is one of the attractive and important strategies for the construction of C=N bonds from the perspective of environmental fri...The transition metal-catalyzed acceptorless dehydrogenative coupling of alcohols and amines is one of the attractive and important strategies for the construction of C=N bonds from the perspective of environmental friendliness and economy.Herein,we report the synthesis of four novel phosphine-free cobalt(II)complexes(Co-1—Co-4)with N,O-bidentate ligands incorporating N-oxide units and their catalytic activity in acceptorless dehydrogenative coupling of benzylic alcohols and aryl amines.X-ray diffraction analyses revealed that the central cobalt atoms in three of the cobalt complexes(Co-1,Co-2,Co-4)were six-coordinated and adopted an octahedral geometry configuration.Catalytic evaluation of cobalt complexes demonstrated that Co-4 exhibited higher activity than the other three cobalt complexes.This system could provide a series of corresponding imine products with good functional groups compatibility and high yields.Especially,the use of phosphine-free and inexpensive cobalt complexes,along with readily accessible N,O-bidentate ligands featuring N-oxide moieties,offers significant advantages for this reaction.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
This work reports on the synthesis and characterization of a series of Schiff-base cobalt(III)complexes 1〜4 that exhibit an obvious catalytic activity for hydrogen production in aqueous solution using fluorescein(FL)a...This work reports on the synthesis and characterization of a series of Schiff-base cobalt(III)complexes 1〜4 that exhibit an obvious catalytic activity for hydrogen production in aqueous solution using fluorescein(FL)and triethanolamine(TEOA)as photosensitizer and electron donor,respectively.The complexes display the capability of splitting of water for H2 evolution.Under optimized conditions,complex 3 shows better properties for photocatalysis,25 mg of which can release 152.3μmol of H_(2) after irradiation for 3 h.The mechanism for light-driven H_(2) production was explored by experiments and density functional theory(DFT).Meanwhile,the reason of releasing hydrogen was explained theoretically in detail.The research results will help to understand the interaction of cobalt complexes with the photosensitizer and design new photocatalysis for the future.展开更多
Two cobalt（Ⅱ） complexes 1 and 2 of Schiff bases derived from amino acids were synthesized and used for oxidation of benzyl alcohol with molecular oxygen at different conditions of pH,solvent,temperature and complex...Two cobalt（Ⅱ） complexes 1 and 2 of Schiff bases derived from amino acids were synthesized and used for oxidation of benzyl alcohol with molecular oxygen at different conditions of pH,solvent,temperature and complex/alcohol molar ratio to optimize reaction conditions and to evaluate the catalytic efficiency of new cobalt Schiff base complexes.Under obtained optimum conditions,various alcohols were oxidized to corresponding aldehydes and ketones.展开更多
The title nickel complex I and cobalt complex II were obtained separately from the direct reaction of D-（＋）-leucinol with Ni（II） chloride and L-（-）-leucinol with Co（II） acetate tetra- hydrate in anhydrous met...The title nickel complex I and cobalt complex II were obtained separately from the direct reaction of D-（＋）-leucinol with Ni（II） chloride and L-（-）-leucinol with Co（II） acetate tetra- hydrate in anhydrous methanol. The crystal structures of I and II were determined by single-crystal X-ray diffraction and further characterized by elemental analysis and IR. For I： [Ni（C18H45N3O3）]Cl2, orthorhombic, P212121, a = 11.2807（9）, b = 14.7115（11）, c = 16.3580（13） A, V = 2714.7（4） A3, Z = 4, Pcalcd = 1.177 Mg/m3, the final R = 0.0407, and 16539 reflections observed with I 〉 2σ（/）; For II： [Co（C45HI08N6015）], trigonal, R3：H, a = 23.981（3）, b =23.981（3）, c = 10.8925（15） A, γ = 120°, V = 5425.1（14） A3, Z = 3, Pcalcd = 1.002 Mg/m3, the final R = 0.0625 for 16556 observed reflections with I 〉 2σ（I）. The complexes were then used to catalyze the Henry reaction and obtained good catalytic results. The catalytic activity of the complexes was determined by IH NMR. And research is going towards the application to other organic reactions such as cyanosilylation reaction.展开更多
A series of mono-and binuclear Co（Ⅱ） complexes （Col-Co7） supported by quinoline-2-imidate ligands were synthesized and thoroughly characterized. Measured by single crystal X-ray crystallography, complexes Col and...A series of mono-and binuclear Co（Ⅱ） complexes （Col-Co7） supported by quinoline-2-imidate ligands were synthesized and thoroughly characterized. Measured by single crystal X-ray crystallography, complexes Col and Co3 adopted distorted tetrahedral structures around the cobalt center. Upon activation by ethylaluminium sesquichloride （EASC）, these cobalt complexes exhibited high catalytic activity and cis-l,4-selectivity towards 1,3-butadiene polymerization. The effects of ligand environment, polymerization temperature, and cocatalyst types on the polymerization were investigated in detail. Interestingly, the binuclear Co（Ⅱ） complexes exhibited high thermal stability, and the polymer yields were up to 97.2% even at a high temperature of 70 ℃.展开更多
Cobait（Ⅱ） nitrate reacted with 1,10-phenanthroline （phen） and 5-sulfosaiicylic acid （H3ssal） to yield the cobait（Ⅰ） complex [Co（phen）2（H2O）2]（Hssal）o4H2O （1） and the reaction of 1 with copper acetate...Cobait（Ⅱ） nitrate reacted with 1,10-phenanthroline （phen） and 5-sulfosaiicylic acid （H3ssal） to yield the cobait（Ⅰ） complex [Co（phen）2（H2O）2]（Hssal）o4H2O （1） and the reaction of 1 with copper acetate led to a novel complex [Co（phen）（H2O）4][Cu2（ssal）2（phen）2]·5H2O （2）. These two complexes were cationanion species and the cationic motif [Co（phen）2（H2O）2]^2＋of 1 could be converted to [Co（phen）（H2O）4]^2＋ in the formation process of new anion [Cu2（phen）2（ssal）2]^2- of 2. In both complexes abundant hydrogen bonds construct different supramolecular architectures, thus the conversion reaction can provide a new path to create novel supramolecular network.展开更多
Two complexes with a zwitterionic dicarboxylate ligand,Mn（L）2（H2O）4 1 and Co（L）2（H2O）4 2（L = 1-carboxymethylpyridinium-4-carboxylate）,were synthesized and structurally characterized.Complex 1 crystallizes in...Two complexes with a zwitterionic dicarboxylate ligand,Mn（L）2（H2O）4 1 and Co（L）2（H2O）4 2（L = 1-carboxymethylpyridinium-4-carboxylate）,were synthesized and structurally characterized.Complex 1 crystallizes in monoclinic,space group P21 with a = 6.490（2）,b = 19.210（7）,c = 7.813（3） ,β = 92.716（5）o,V = 972.9（6） 3,Z = 2,Mr = 487.28,Dc = 1.663 g/cm3,F（000） = 502,μ = 0.749 mm-1,S = 1.060,the final R = 0.0377 and wR = 0.0893 for 3292 observed reflections with I 2σ（I）.Complex 2 is isomorphous with 1,with a = 6.478（2）,b = 19.052（7）,c = 7.742（3） ,β = 92.690（4）o,V = 954.6（6） 3,Z = 2,Mr = 491.28,Dc = 1.709 g/cm3,F（000） = 506,μ = 0.971 mm-1,S = 1.035,the final R = 0.0425 and wR = 0.0809 for 3289 observed reflections with I 2σ（I）.In the compounds,the mononuclear [M（L）2（H2O）4] units with trans-octahedral coordination geometry are linked into 3D architectures via hydrogen bonding（or second-sphere coordination） involving carboxylate groups and coordinated water molecules.The 3D networks illustrate a 3,8-connected net with Schlfli symbol（4·62）2（42·623·83）.展开更多
Two new Co（Ⅱ） coordination polymers,{[Co_3（Hchda）_2（chda）_2（bpp）_2（H_2O）_2]}_n 1 and {[Co（chda）（bpe）（H_2O）]·3H_2O}_n 2（H_2chda = 1,1-cyclohexanediacetic acid,bpp = 1,3-bis（4-pyridinyl）propane ...Two new Co（Ⅱ） coordination polymers,{[Co_3（Hchda）_2（chda）_2（bpp）_2（H_2O）_2]}_n 1 and {[Co（chda）（bpe）（H_2O）]·3H_2O}_n 2（H_2chda = 1,1-cyclohexanediacetic acid,bpp = 1,3-bis（4-pyridinyl）propane and bpe = 1,2-bis（4-pyridinyl）ethylene）,were hydrothermally synthesized and then characterized by elemental analysis,IR spectroscopy,thermogravimetric analysis（TGA）,and single-crystal X-ray diffraction.Complex 1 possesses an infinite metal-organic layer based on triply bridged linear trinuclear subunits and complex 2 exhibits a square（4,4） grid layer with dangling lateral arms resulting from eight-membered rings above and below the layer.In addition,magnetic properties of complexes 1 and 2 are also given.展开更多
Two new metal-organic complexes,{[Co2（bptc）（DPPZ）2（H2O）2]·H2O}n 1 and {[Co2（ccm）2（DPPZ）2]·2H2O}n 2,were obtained by the hydrothermal reactions of Co（NO3）2·6H2O with chelating ligand dipyrido...Two new metal-organic complexes,{[Co2（bptc）（DPPZ）2（H2O）2]·H2O}n 1 and {[Co2（ccm）2（DPPZ）2]·2H2O}n 2,were obtained by the hydrothermal reactions of Co（NO3）2·6H2O with chelating ligand dipyrido[3,2-a：2＇,3＇-c]phenazine（DPPZ） and the corresponding carboxylic acid,namely,3,3＇,4,4＇-benzophenonetetracarboxylic acid（H4bptc） or 2-carboxycinnamic acid（H2ccm）,respectively.The complexes were structurally characterized by single-crystal X-ray diffraction,elemental analyses,IR spectra,and thermal gravimetry.1 presents unique chiral chain structures,which are further consolidated into three-dimensional supramolecular frameworks via noncovalent bonds,such as hydrogen bonding and π-π interactions.2 features infinite double-chain structures,which are connected by strong π-π interactions to result in three-dimensional supramolecular architectures.展开更多
Novel unsymmetrical bissalicylaldimine bis-Schiff bases with a benzo-10-aza-15-crown-5 pendant and their cobalt complexes have been synthesized via condensation of 3 or 5-[（benzo-10-aza-15-crown-5）-10-ylmethyl] sali...Novel unsymmetrical bissalicylaldimine bis-Schiff bases with a benzo-10-aza-15-crown-5 pendant and their cobalt complexes have been synthesized via condensation of 3 or 5-[（benzo-10-aza-15-crown-5）-10-ylmethyl] salicylaldehyde with the half unit Schiff bases and characterized by ^1H NMR, IR, mass spectroscopy, elemental analysis, molar conductances and molar magnetic susceptibility.展开更多
Introduction The compounds that can take up and release molecular oxygen reversibly is of significance because they can be used as model compounds for the study of the reversible oxygenation mechanisms involved in the...Introduction The compounds that can take up and release molecular oxygen reversibly is of significance because they can be used as model compounds for the study of the reversible oxygenation mechanisms involved in the very complex natural oxygen carriers, e.g., the hemoglobins and hemocyanins, and as the means of separating molecular oxygen from the air. The dioxygen carriers extensively studied are the Cobalt展开更多
Reactions of 1,3-bis（pyridyl-4-ylthio）propan-2-one L and COCl2·6H2O under different conditions gave two new cobalt（Ⅱ）-chloride-L complexes with distinct structures. Complex [Co（L）2Cl2]·0.5CH3OH}n 1 pr...Reactions of 1,3-bis（pyridyl-4-ylthio）propan-2-one L and COCl2·6H2O under different conditions gave two new cobalt（Ⅱ）-chloride-L complexes with distinct structures. Complex [Co（L）2Cl2]·0.5CH3OH}n 1 prepared by solvothermal treatment is a 3D network, whereas complex {[Co3（L）2Cl6（DMF）4]·2CH3OH·H2O} 2 obtained in DMF-diethyl ether system is a discrete acyclic trimer. Crystal data for 1： space group lbca, a = 15.993（4）, b = 18.454（5）, c = 21.506（6）A, V= 6347（3） ,A^3, Z = 8, Dc = 1.462 g/cm^3,μ = 1.005 mm^-1, F（000） = 2864, C26.5H26Cl2CoN4O2.5S4, Mr = 698.58, the final R = 0.0499 and wR = 0.1024. Crystal data for 2： space group P1^-, a = 9.9177（6）, b = 11.0871 （4）, c = 15.5490（12） ,A, α = 83.1834（14）,β = 88.910（13）, γ = 71.096（ 11 ）°, V = 1605.8（2） A^3, Z = 1, Dc = 1.362 g/cm^3,μ= 1.194 mm^-1, F（000） = 677, C40H62Cl6Co3N8O9S4, Mr = 1316.71, the final R = 0.0666 and wR =0.1575.展开更多
Complexes [MCl 2{CH 3N(CH 2CH 2N[CDS1]CR 1R 2) 2}]((3, M=Co, R 1=H, R 2=Ph ; 4, M=Fe, R 1=H, \{R 2=Ph\}; 5, M=Co, R 1=R 2=Ph) were prepared and characterized by IR spectra and elemental analysis. The combination of ea...Complexes [MCl 2{CH 3N(CH 2CH 2N[CDS1]CR 1R 2) 2}]((3, M=Co, R 1=H, R 2=Ph ; 4, M=Fe, R 1=H, \{R 2=Ph\}; 5, M=Co, R 1=R 2=Ph) were prepared and characterized by IR spectra and elemental analysis. The combination of each of complexes 3-5 with ethylaluminoxane(EAO), respectively, was found to be moderately active for ethylene oligomerization to low carbon olefins. The activity of 113 kg oligomers·mol -1 Co·h -1 for complex 3(100 mol of EAO, 180 ℃ and 1 8 MPa ethylene) was observed with a selectivity of 93% to C 4-10 olefins, of which 96% were linear C4 10 olefins. The catalytic properties of complexes 3-5 were compared with those of analogous P,P coordinated complexes [MCl 2{CH 3N(CH 2CH 2PPh 2) 2}](1, M=Co; 2, \{M=\}Fe).展开更多
Two new cobalt（II） supramolecular complexes [Co（4,4＇-bipy）2（H2O）4]·[Co2（4,4＇-bipy）3（H2O）8]·2TST·2（4,4＇-bipy）·4H2O 1 and [Co（4,4＇-bipy）2（H2O）4]DSNT·4,4＇-bipy 2 based upon t...Two new cobalt（II） supramolecular complexes [Co（4,4＇-bipy）2（H2O）4]·[Co2（4,4＇-bipy）3（H2O）8]·2TST·2（4,4＇-bipy）·4H2O 1 and [Co（4,4＇-bipy）2（H2O）4]DSNT·4,4＇-bipy 2 based upon the assembly of Co（II）, 4,4＇-bipyridine （4,4＇-bipy） and two new multifunctional organic ligands, 2,4,6-tris（4-sulfophenyl- amino）-1,3,5-triazine （H3TST） and 2,4-bis（p-sulfanilato）-6-diethylamino-1,3,5-triazine （H2DSNT）, have been prepared by hydrothermal method and characterized by elemental analysis, IR spectrum, and single-crystal X-ray diffraction. The crystal structure of 1 is of monoclinic, space group P21/n with a = 13.599（4）, b = 18.988（6）, c = 22.995（7） A, β = 90.273（6）°, V = 5938（3）A^3, Z = 4, C56H59Co1.5N13O17S3, Mr = 1370.74, Dc = 1.533 g/cm^3, μ = 0.613 mm^-1, F（000） = 2842, GOOF = 1.018, the final R = 0.0796 and wR = 0.1498 for 9019 observed reflections with I 〉 2σ（I）. The crystal structure of 2 belongs to the monoclinic system, space group C2/c with a = 18.864（6）, b = 14.283（5）, c = 20.246（7）A, β = 107.799（6）°, V = 5194（3）A^3, Z = 4, C49H52CoN12O10S2, Mr = 1092.08, Dc = 1.397 g/cm^3, μ = 0.480 mm^-1, F（000） = 2276, GOOF = 1.059, the final R = 0.0665 and wR = 0.1900 for 4887 observed reflections with I 〉 2σ（I）. The results of X-ray crystal structure analysis revealed that complexes 1 and 2 exhibit layered supramolecular frameworks stabilized by electrostatic interactions, π-π interactions and hydrogen bonds.展开更多
Two novel L-amino alcohol coordination cobalt and copper complexes I and Ⅱ were obtained separately from the direct reaction of L-plenylglycinol with Co（Ⅱ） acetate tetrahydrate in anhydrous ethanol and L-leucinol ...Two novel L-amino alcohol coordination cobalt and copper complexes I and Ⅱ were obtained separately from the direct reaction of L-plenylglycinol with Co（Ⅱ） acetate tetrahydrate in anhydrous ethanol and L-leucinol with Cu（Ⅱ） chloride dihydrate in anhydrous methanol. The structures of I and Ⅱ were determined by single-crystal X-ray diffraction and further characterized by elemental analysis and IR. For I： [Co3（C51H66N3O16）]2（OAc）, monoclinic, space group P21, a = 15.022（3）, b = 14.242（3）, c = 28.922（6） A, β = 98.944（4）°, V = 6112（2） A3, Z = 4, Dc = 1.339 g/cm^3, the final R = 0.0860 for 21906 observed reflections with I 〉 2（I）. For Ⅱ： Cu2[C24H58N4O7Cl]Cl, orthorhombic, space group P212121, a = 6.1861（13）, b = 20.838（4）, c = 28.274（6） , V = 3644.6（13） 3, Z = 4, Dc = 1.310 g/cm^3, the final R = 0.0642 for 11106 observed reflections with I 〉 2（I）. The complexes were then used to catalyze the Henry reaction and catalytic activity determined by 1H NMR.展开更多
A nonsymmetrical PNN pincer ligand[6-(^(t)Bu_(2)PNH)C_(5)H_(4)N-2-(3-Mes)C_(3)H_(2)N_(2)]and its corresponding cobalt-N_(2)complex were synthesized and characterized.By the stoichiometric reaction of the PNN ligand li...A nonsymmetrical PNN pincer ligand[6-(^(t)Bu_(2)PNH)C_(5)H_(4)N-2-(3-Mes)C_(3)H_(2)N_(2)]and its corresponding cobalt-N_(2)complex were synthesized and characterized.By the stoichiometric reaction of the PNN ligand lithium salt with CoCl_(2),the complex 3,(PNN)CoCl,was obtained.Then,reduction of 3 with NaBHEt3under a dinitrogen atmosphere yielded complex 5,(PNN)Co(Ⅰ)(η^(1)-N_(2)).Single-crystal X-ray analysis,IR spectrum,and DFT calculations revealed that the dinitrogen in 5 was only weakly reduced by the cobalt center.The reactions of 5 with carbon monoxide and 2,6-dimethylphenyl isocyanide gave carbonyl and isocyanide complexes 6 and 7 with the release of N_(2),respectively.Furthermore,these cobalt complexes,especially complex 5,demonstrated the capacity to convert dinitrogen to N(TMS)_(3)with moderate efficiency.展开更多
文摘Three cobalt complexes bearing tunable,redox-active bipyridyl N-heterocyclic carbene(NHC)-based ligands have been studied for electrocatalytic hydrogen evolution from aqueous solutions.The effect of structural modifications to the ligand framework is investigated across the catalyst series,which includes a non-macrocyclic derivative(1-Co)and 16-(2-Co)and 15-(3-Co)membered macrocycles.A structure-activity relationship is demonstrated,in which the macrocyclic complexes have greater activity compared to their non-macrocyclic counterpart with the most rigid catalyst,supported by the 15-membered macrocycle,performing best overall.Indeed,3-Co catalyzes H2 evolution from aqueous pH 4 acetate buffer with a Faradaic efficiency of 97%at a low overpotential of 330 mV.Mechanistic studies are consistent with formation of a cobalt-hydride species that is subsequently protonated to evolve H2 via a heterolytic pathway.
文摘The catalytic properties of a series of cobalt complexes containing bidenated nitrogen ligand for displacement reaction of trialkylaluminum with ethylene is reported. Effect of different reaction time, temperature and cobalt complexes containing different ligand on catalyst performance has been investigated.
基金supported by Fundamental Research Program of Shanxi Province(No.201901D111276)Postgraduate Education Innovation Program of Shanxi Province(Nos.2024KY458,2024JG104).
文摘The transition metal-catalyzed acceptorless dehydrogenative coupling of alcohols and amines is one of the attractive and important strategies for the construction of C=N bonds from the perspective of environmental friendliness and economy.Herein,we report the synthesis of four novel phosphine-free cobalt(II)complexes(Co-1—Co-4)with N,O-bidentate ligands incorporating N-oxide units and their catalytic activity in acceptorless dehydrogenative coupling of benzylic alcohols and aryl amines.X-ray diffraction analyses revealed that the central cobalt atoms in three of the cobalt complexes(Co-1,Co-2,Co-4)were six-coordinated and adopted an octahedral geometry configuration.Catalytic evaluation of cobalt complexes demonstrated that Co-4 exhibited higher activity than the other three cobalt complexes.This system could provide a series of corresponding imine products with good functional groups compatibility and high yields.Especially,the use of phosphine-free and inexpensive cobalt complexes,along with readily accessible N,O-bidentate ligands featuring N-oxide moieties,offers significant advantages for this reaction.
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.
基金This work was supported by the Natural Science Foundation of Anhui Province for Distinguished Young Scholars(1808085J24)the Natural Science Foundation of Anhui Province(1808085MB45)+1 种基金the Natural Science Foundation of Educational Committee of Anhui Province(KJ2020A0022)the Excellent Youth Talent Support Program of Anhui Province(gxyq2020101)。
文摘This work reports on the synthesis and characterization of a series of Schiff-base cobalt(III)complexes 1〜4 that exhibit an obvious catalytic activity for hydrogen production in aqueous solution using fluorescein(FL)and triethanolamine(TEOA)as photosensitizer and electron donor,respectively.The complexes display the capability of splitting of water for H2 evolution.Under optimized conditions,complex 3 shows better properties for photocatalysis,25 mg of which can release 152.3μmol of H_(2) after irradiation for 3 h.The mechanism for light-driven H_(2) production was explored by experiments and density functional theory(DFT).Meanwhile,the reason of releasing hydrogen was explained theoretically in detail.The research results will help to understand the interaction of cobalt complexes with the photosensitizer and design new photocatalysis for the future.
文摘Two cobalt（Ⅱ） complexes 1 and 2 of Schiff bases derived from amino acids were synthesized and used for oxidation of benzyl alcohol with molecular oxygen at different conditions of pH,solvent,temperature and complex/alcohol molar ratio to optimize reaction conditions and to evaluate the catalytic efficiency of new cobalt Schiff base complexes.Under obtained optimum conditions,various alcohols were oxidized to corresponding aldehydes and ketones.
文摘The title nickel complex I and cobalt complex II were obtained separately from the direct reaction of D-（＋）-leucinol with Ni（II） chloride and L-（-）-leucinol with Co（II） acetate tetra- hydrate in anhydrous methanol. The crystal structures of I and II were determined by single-crystal X-ray diffraction and further characterized by elemental analysis and IR. For I： [Ni（C18H45N3O3）]Cl2, orthorhombic, P212121, a = 11.2807（9）, b = 14.7115（11）, c = 16.3580（13） A, V = 2714.7（4） A3, Z = 4, Pcalcd = 1.177 Mg/m3, the final R = 0.0407, and 16539 reflections observed with I 〉 2σ（/）; For II： [Co（C45HI08N6015）], trigonal, R3：H, a = 23.981（3）, b =23.981（3）, c = 10.8925（15） A, γ = 120°, V = 5425.1（14） A3, Z = 3, Pcalcd = 1.002 Mg/m3, the final R = 0.0625 for 16556 observed reflections with I 〉 2σ（I）. The complexes were then used to catalyze the Henry reaction and obtained good catalytic results. The catalytic activity of the complexes was determined by IH NMR. And research is going towards the application to other organic reactions such as cyanosilylation reaction.
基金financially supported by the National Key R&D Program of China (No.2017YFB0307100 (2017YFB0307103))National Basic Research Program of China (No.2015CB654700 (2015CB654702))
文摘A series of mono-and binuclear Co（Ⅱ） complexes （Col-Co7） supported by quinoline-2-imidate ligands were synthesized and thoroughly characterized. Measured by single crystal X-ray crystallography, complexes Col and Co3 adopted distorted tetrahedral structures around the cobalt center. Upon activation by ethylaluminium sesquichloride （EASC）, these cobalt complexes exhibited high catalytic activity and cis-l,4-selectivity towards 1,3-butadiene polymerization. The effects of ligand environment, polymerization temperature, and cocatalyst types on the polymerization were investigated in detail. Interestingly, the binuclear Co（Ⅱ） complexes exhibited high thermal stability, and the polymer yields were up to 97.2% even at a high temperature of 70 ℃.
基金Project supported by the National Natural Science Foundation of China （No. 50073019）.
文摘Cobait（Ⅱ） nitrate reacted with 1,10-phenanthroline （phen） and 5-sulfosaiicylic acid （H3ssal） to yield the cobait（Ⅰ） complex [Co（phen）2（H2O）2]（Hssal）o4H2O （1） and the reaction of 1 with copper acetate led to a novel complex [Co（phen）（H2O）4][Cu2（ssal）2（phen）2]·5H2O （2）. These two complexes were cationanion species and the cationic motif [Co（phen）2（H2O）2]^2＋of 1 could be converted to [Co（phen）（H2O）4]^2＋ in the formation process of new anion [Cu2（phen）2（ssal）2]^2- of 2. In both complexes abundant hydrogen bonds construct different supramolecular architectures, thus the conversion reaction can provide a new path to create novel supramolecular network.
基金Supported by NNSFC (20771038)Shanghai Leading Academic Discipline Project (B409)
文摘Two complexes with a zwitterionic dicarboxylate ligand,Mn（L）2（H2O）4 1 and Co（L）2（H2O）4 2（L = 1-carboxymethylpyridinium-4-carboxylate）,were synthesized and structurally characterized.Complex 1 crystallizes in monoclinic,space group P21 with a = 6.490（2）,b = 19.210（7）,c = 7.813（3） ,β = 92.716（5）o,V = 972.9（6） 3,Z = 2,Mr = 487.28,Dc = 1.663 g/cm3,F（000） = 502,μ = 0.749 mm-1,S = 1.060,the final R = 0.0377 and wR = 0.0893 for 3292 observed reflections with I 2σ（I）.Complex 2 is isomorphous with 1,with a = 6.478（2）,b = 19.052（7）,c = 7.742（3） ,β = 92.690（4）o,V = 954.6（6） 3,Z = 2,Mr = 491.28,Dc = 1.709 g/cm3,F（000） = 506,μ = 0.971 mm-1,S = 1.035,the final R = 0.0425 and wR = 0.0809 for 3289 observed reflections with I 2σ（I）.In the compounds,the mononuclear [M（L）2（H2O）4] units with trans-octahedral coordination geometry are linked into 3D architectures via hydrogen bonding（or second-sphere coordination） involving carboxylate groups and coordinated water molecules.The 3D networks illustrate a 3,8-connected net with Schlfli symbol（4·62）2（42·623·83）.
基金supported by the National Natural Science Foundation of China(No.21571093)the Program for Science&Technology Innovation Talents in Universities of Henan Province(No.14HASTIT017)+1 种基金the Program for Innovative Research Team(in Science and Technology)in University of Henan Province(No.14IRTSTHN008)the Foundation of Education Committee of Henan Province(No.142300410301)
文摘Two new Co（Ⅱ） coordination polymers,{[Co_3（Hchda）_2（chda）_2（bpp）_2（H_2O）_2]}_n 1 and {[Co（chda）（bpe）（H_2O）]·3H_2O}_n 2（H_2chda = 1,1-cyclohexanediacetic acid,bpp = 1,3-bis（4-pyridinyl）propane and bpe = 1,2-bis（4-pyridinyl）ethylene）,were hydrothermally synthesized and then characterized by elemental analysis,IR spectroscopy,thermogravimetric analysis（TGA）,and single-crystal X-ray diffraction.Complex 1 possesses an infinite metal-organic layer based on triply bridged linear trinuclear subunits and complex 2 exhibits a square（4,4） grid layer with dangling lateral arms resulting from eight-membered rings above and below the layer.In addition,magnetic properties of complexes 1 and 2 are also given.
基金Supported by the National Natural Science Foundation of China (No. 60978059)Program for New Century Excellent Talents in University (NCET-10-0176)the Natural Science Foundation of Jilin Province (No. 20090527)
文摘Two new metal-organic complexes,{[Co2（bptc）（DPPZ）2（H2O）2]·H2O}n 1 and {[Co2（ccm）2（DPPZ）2]·2H2O}n 2,were obtained by the hydrothermal reactions of Co（NO3）2·6H2O with chelating ligand dipyrido[3,2-a：2＇,3＇-c]phenazine（DPPZ） and the corresponding carboxylic acid,namely,3,3＇,4,4＇-benzophenonetetracarboxylic acid（H4bptc） or 2-carboxycinnamic acid（H2ccm）,respectively.The complexes were structurally characterized by single-crystal X-ray diffraction,elemental analyses,IR spectra,and thermal gravimetry.1 presents unique chiral chain structures,which are further consolidated into three-dimensional supramolecular frameworks via noncovalent bonds,such as hydrogen bonding and π-π interactions.2 features infinite double-chain structures,which are connected by strong π-π interactions to result in three-dimensional supramolecular architectures.
基金Prgject supported by the National Natural Science Foundation of China （No. 29572059, and Key Project of Sichuan Province Education 0ffice （No. 2005D007）.
文摘Novel unsymmetrical bissalicylaldimine bis-Schiff bases with a benzo-10-aza-15-crown-5 pendant and their cobalt complexes have been synthesized via condensation of 3 or 5-[（benzo-10-aza-15-crown-5）-10-ylmethyl] salicylaldehyde with the half unit Schiff bases and characterized by ^1H NMR, IR, mass spectroscopy, elemental analysis, molar conductances and molar magnetic susceptibility.
基金Supported by Shandong University Youth Scientific Foundation
文摘Introduction The compounds that can take up and release molecular oxygen reversibly is of significance because they can be used as model compounds for the study of the reversible oxygenation mechanisms involved in the very complex natural oxygen carriers, e.g., the hemoglobins and hemocyanins, and as the means of separating molecular oxygen from the air. The dioxygen carriers extensively studied are the Cobalt
基金This work was financially support by NNSFC (No. 20231020), NSF of Fujian Province and the Key Project from CAS
文摘Reactions of 1,3-bis（pyridyl-4-ylthio）propan-2-one L and COCl2·6H2O under different conditions gave two new cobalt（Ⅱ）-chloride-L complexes with distinct structures. Complex [Co（L）2Cl2]·0.5CH3OH}n 1 prepared by solvothermal treatment is a 3D network, whereas complex {[Co3（L）2Cl6（DMF）4]·2CH3OH·H2O} 2 obtained in DMF-diethyl ether system is a discrete acyclic trimer. Crystal data for 1： space group lbca, a = 15.993（4）, b = 18.454（5）, c = 21.506（6）A, V= 6347（3） ,A^3, Z = 8, Dc = 1.462 g/cm^3,μ = 1.005 mm^-1, F（000） = 2864, C26.5H26Cl2CoN4O2.5S4, Mr = 698.58, the final R = 0.0499 and wR = 0.1024. Crystal data for 2： space group P1^-, a = 9.9177（6）, b = 11.0871 （4）, c = 15.5490（12） ,A, α = 83.1834（14）,β = 88.910（13）, γ = 71.096（ 11 ）°, V = 1605.8（2） A^3, Z = 1, Dc = 1.362 g/cm^3,μ= 1.194 mm^-1, F（000） = 677, C40H62Cl6Co3N8O9S4, Mr = 1316.71, the final R = 0.0666 and wR =0.1575.
基金Supported by the National Natural Science Foundation of China(No.2 0 1730 0 6 )
文摘Complexes [MCl 2{CH 3N(CH 2CH 2N[CDS1]CR 1R 2) 2}]((3, M=Co, R 1=H, R 2=Ph ; 4, M=Fe, R 1=H, \{R 2=Ph\}; 5, M=Co, R 1=R 2=Ph) were prepared and characterized by IR spectra and elemental analysis. The combination of each of complexes 3-5 with ethylaluminoxane(EAO), respectively, was found to be moderately active for ethylene oligomerization to low carbon olefins. The activity of 113 kg oligomers·mol -1 Co·h -1 for complex 3(100 mol of EAO, 180 ℃ and 1 8 MPa ethylene) was observed with a selectivity of 93% to C 4-10 olefins, of which 96% were linear C4 10 olefins. The catalytic properties of complexes 3-5 were compared with those of analogous P,P coordinated complexes [MCl 2{CH 3N(CH 2CH 2PPh 2) 2}](1, M=Co; 2, \{M=\}Fe).
基金financially supported by the National Natural Science Foundation of China (20973174)the Project of Fujian Province (2007F3115 and 2006F3133)
文摘Two new cobalt（II） supramolecular complexes [Co（4,4＇-bipy）2（H2O）4]·[Co2（4,4＇-bipy）3（H2O）8]·2TST·2（4,4＇-bipy）·4H2O 1 and [Co（4,4＇-bipy）2（H2O）4]DSNT·4,4＇-bipy 2 based upon the assembly of Co（II）, 4,4＇-bipyridine （4,4＇-bipy） and two new multifunctional organic ligands, 2,4,6-tris（4-sulfophenyl- amino）-1,3,5-triazine （H3TST） and 2,4-bis（p-sulfanilato）-6-diethylamino-1,3,5-triazine （H2DSNT）, have been prepared by hydrothermal method and characterized by elemental analysis, IR spectrum, and single-crystal X-ray diffraction. The crystal structure of 1 is of monoclinic, space group P21/n with a = 13.599（4）, b = 18.988（6）, c = 22.995（7） A, β = 90.273（6）°, V = 5938（3）A^3, Z = 4, C56H59Co1.5N13O17S3, Mr = 1370.74, Dc = 1.533 g/cm^3, μ = 0.613 mm^-1, F（000） = 2842, GOOF = 1.018, the final R = 0.0796 and wR = 0.1498 for 9019 observed reflections with I 〉 2σ（I）. The crystal structure of 2 belongs to the monoclinic system, space group C2/c with a = 18.864（6）, b = 14.283（5）, c = 20.246（7）A, β = 107.799（6）°, V = 5194（3）A^3, Z = 4, C49H52CoN12O10S2, Mr = 1092.08, Dc = 1.397 g/cm^3, μ = 0.480 mm^-1, F（000） = 2276, GOOF = 1.059, the final R = 0.0665 and wR = 0.1900 for 4887 observed reflections with I 〉 2σ（I）. The results of X-ray crystal structure analysis revealed that complexes 1 and 2 exhibit layered supramolecular frameworks stabilized by electrostatic interactions, π-π interactions and hydrogen bonds.
文摘Two novel L-amino alcohol coordination cobalt and copper complexes I and Ⅱ were obtained separately from the direct reaction of L-plenylglycinol with Co（Ⅱ） acetate tetrahydrate in anhydrous ethanol and L-leucinol with Cu（Ⅱ） chloride dihydrate in anhydrous methanol. The structures of I and Ⅱ were determined by single-crystal X-ray diffraction and further characterized by elemental analysis and IR. For I： [Co3（C51H66N3O16）]2（OAc）, monoclinic, space group P21, a = 15.022（3）, b = 14.242（3）, c = 28.922（6） A, β = 98.944（4）°, V = 6112（2） A3, Z = 4, Dc = 1.339 g/cm^3, the final R = 0.0860 for 21906 observed reflections with I 〉 2（I）. For Ⅱ： Cu2[C24H58N4O7Cl]Cl, orthorhombic, space group P212121, a = 6.1861（13）, b = 20.838（4）, c = 28.274（6） , V = 3644.6（13） 3, Z = 4, Dc = 1.310 g/cm^3, the final R = 0.0642 for 11106 observed reflections with I 〉 2（I）. The complexes were then used to catalyze the Henry reaction and catalytic activity determined by 1H NMR.
基金supported by the National Natural Science Foundation of China(Nos.21988101 and 22201013)Beijing Natural Science Foundation(No.2222008)supported by the High-performance Computing Platform of Peking University。
文摘A nonsymmetrical PNN pincer ligand[6-(^(t)Bu_(2)PNH)C_(5)H_(4)N-2-(3-Mes)C_(3)H_(2)N_(2)]and its corresponding cobalt-N_(2)complex were synthesized and characterized.By the stoichiometric reaction of the PNN ligand lithium salt with CoCl_(2),the complex 3,(PNN)CoCl,was obtained.Then,reduction of 3 with NaBHEt3under a dinitrogen atmosphere yielded complex 5,(PNN)Co(Ⅰ)(η^(1)-N_(2)).Single-crystal X-ray analysis,IR spectrum,and DFT calculations revealed that the dinitrogen in 5 was only weakly reduced by the cobalt center.The reactions of 5 with carbon monoxide and 2,6-dimethylphenyl isocyanide gave carbonyl and isocyanide complexes 6 and 7 with the release of N_(2),respectively.Furthermore,these cobalt complexes,especially complex 5,demonstrated the capacity to convert dinitrogen to N(TMS)_(3)with moderate efficiency.
