The reaction of trinuclear molybdenum cluster{Mo_3S_4(μ-dtp)(dtp)_3(H_2O)}1[dtp= S_2P(OEt)_2]with RCO_2Na(R=H,CH_3)in the presence of Py gave the black compounds{Mo_3S_4(μ- O_2CR)(dtp)_3(Py)}(2,R=H,3,R=CH_3).Both co...The reaction of trinuclear molybdenum cluster{Mo_3S_4(μ-dtp)(dtp)_3(H_2O)}1[dtp= S_2P(OEt)_2]with RCO_2Na(R=H,CH_3)in the presence of Py gave the black compounds{Mo_3S_4(μ- O_2CR)(dtp)_3(Py)}(2,R=H,3,R=CH_3).Both compounds are characterized by X-ray crystallo- graphy.It is shown that crystals 2 and 3 belong to space group P with Z=2 and a=10.519(2),b= 12.121(2),c=15.757(2),α=93.27(1),β=94.63(1),γ=105.22(1)°,V=1925~3 for crystal 2,whereas a=9.556(2),b=14.067(7),c=15.914(9),α=101.41(4),β=101.44(4),γ=74.26(3)°,V=1994~3 for crystal 3.The final R factors are 0.041 and 0.048 for crystal 2 and 3 respectively.The structure analysis indicates that(O_2CR)^- ligand selectively substitutes the bridging(dtp)ligand.This type of Mo_3 cluster molecule where structure contains two species of bidentate ligand is for the first time to be obtained by us.展开更多
A systematic investigation of oxidation on a superconductive Fe Te_（0.5）Se_（0.5）thin film,which was grown on Nb-doped SrTiO_3（001） by pulsed laser deposition,has been carried out.The sample was exposed to ambien...A systematic investigation of oxidation on a superconductive Fe Te_（0.5）Se_（0.5）thin film,which was grown on Nb-doped SrTiO_3（001） by pulsed laser deposition,has been carried out.The sample was exposed to ambient air for one month for oxidation.Macroscopically,the exposed specimen lost its superconductivity due to oxidation.The specimen was subjected to in situ synchrotron radiation photoelectron spectroscopy（PES） and x-ray absorption spectroscopy（XAS） measurements following cycles of annealing and argon ion etching treatments to unravel what happened in the electronic structure and composition after exposure to air.By the spectroscopic measurements,we found that the as-grown FeTe_（0.5）Se_（0.5）superconductive thin film experienced an element selective substitution reaction.The oxidation preferentially proceeds through pumping out the Te and forming Fe–O bonds by O substitution of Te.In addition,our results certify that in situ vacuum annealing and low-energy argon ion etching methods combined with spectroscopy are suitable for depth element and valence analysis of layered structure superconductor materials.展开更多
A copper-catalyzed stereoselective 1,3-dipolar cycloaddition of methyleneindolinones and N,N0-cyclic azomethine imines has been developed under mild reaction conditions.The spiro[pyrazolidin-3,30-oxindoles] were obtai...A copper-catalyzed stereoselective 1,3-dipolar cycloaddition of methyleneindolinones and N,N0-cyclic azomethine imines has been developed under mild reaction conditions.The spiro[pyrazolidin-3,30-oxindoles] were obtained in moderate to high isolated yields（up to 82%） with good stereoselevtivities（up to 15：1） in the presence of 5 mol% of Cu（OAc）2at room temperature.展开更多
文摘The reaction of trinuclear molybdenum cluster{Mo_3S_4(μ-dtp)(dtp)_3(H_2O)}1[dtp= S_2P(OEt)_2]with RCO_2Na(R=H,CH_3)in the presence of Py gave the black compounds{Mo_3S_4(μ- O_2CR)(dtp)_3(Py)}(2,R=H,3,R=CH_3).Both compounds are characterized by X-ray crystallo- graphy.It is shown that crystals 2 and 3 belong to space group P with Z=2 and a=10.519(2),b= 12.121(2),c=15.757(2),α=93.27(1),β=94.63(1),γ=105.22(1)°,V=1925~3 for crystal 2,whereas a=9.556(2),b=14.067(7),c=15.914(9),α=101.41(4),β=101.44(4),γ=74.26(3)°,V=1994~3 for crystal 3.The final R factors are 0.041 and 0.048 for crystal 2 and 3 respectively.The structure analysis indicates that(O_2CR)^- ligand selectively substitutes the bridging(dtp)ligand.This type of Mo_3 cluster molecule where structure contains two species of bidentate ligand is for the first time to be obtained by us.
基金Project supported by the Chinese Academy of Sciences(Grant No.1G2009312311750101)the National Natural Science Foundation of China(Grant Nos.11375228,11204303,and U1332105)
文摘A systematic investigation of oxidation on a superconductive Fe Te_（0.5）Se_（0.5）thin film,which was grown on Nb-doped SrTiO_3（001） by pulsed laser deposition,has been carried out.The sample was exposed to ambient air for one month for oxidation.Macroscopically,the exposed specimen lost its superconductivity due to oxidation.The specimen was subjected to in situ synchrotron radiation photoelectron spectroscopy（PES） and x-ray absorption spectroscopy（XAS） measurements following cycles of annealing and argon ion etching treatments to unravel what happened in the electronic structure and composition after exposure to air.By the spectroscopic measurements,we found that the as-grown FeTe_（0.5）Se_（0.5）superconductive thin film experienced an element selective substitution reaction.The oxidation preferentially proceeds through pumping out the Te and forming Fe–O bonds by O substitution of Te.In addition,our results certify that in situ vacuum annealing and low-energy argon ion etching methods combined with spectroscopy are suitable for depth element and valence analysis of layered structure superconductor materials.
基金the National Natural Science Foundation of China (No.21172023)Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) and STD of Jiangsu Province for their financial supports
文摘A copper-catalyzed stereoselective 1,3-dipolar cycloaddition of methyleneindolinones and N,N0-cyclic azomethine imines has been developed under mild reaction conditions.The spiro[pyrazolidin-3,30-oxindoles] were obtained in moderate to high isolated yields（up to 82%） with good stereoselevtivities（up to 15：1） in the presence of 5 mol% of Cu（OAc）2at room temperature.
