The stable configurations and hydrogen bond nature of （H2O）n clusters （n = 3-6） have been investigated by the B3LYP method at the 6-31＋＋g^＊＊ level. Upon calculation, four conclusions have been drawn： （1） In...The stable configurations and hydrogen bond nature of （H2O）n clusters （n = 3-6） have been investigated by the B3LYP method at the 6-31＋＋g^＊＊ level. Upon calculation, four conclusions have been drawn： （1） In the （H2O）3-5 clusters, cyclic configurations were confirmed to be the most stable. But in the （H2O）3-4 ones, only cyclic configurations could be observed. From n = 5 （（H2O）5 clusters）, three-dimensional configuration could be found： （2） In the （H2O）6 clusters, all configurations are inclined to be three-dimensional except the most stable configuration which is cyclic; （3） The stable order of （H2O）6 clusters indicates that it is the arrangement of hydrogen bond that plays a decisive role in the cluster stabilities, the zero-point energy is also important, and cluster stabilities are independent on the number of hydrogen bonds; （4） There exist strong cooperativity and superadditivity in the （H2O）n clusters.展开更多
The microhydration structure of nickel sulfate aqueous solution has been determined via density functional theory (DFT) calculation and extended X-ray absorption fine structure (EXAFS) spectroscopy.The geometric optim...The microhydration structure of nickel sulfate aqueous solution has been determined via density functional theory (DFT) calculation and extended X-ray absorption fine structure (EXAFS) spectroscopy.The geometric optimization and energy calculation of nickel sulfate hydrated clusters of the molecular formula [NiSO4(H2O)n ]^0 (n=1-12) were determined via DFT using the B3LYP method.Several possible initial structures were considered for clusters of each size to locate the equilibrium geometry.Based on the DFT calculation,the favorable structure of Ni^2+ includes the six-coordinated form of [NiSO4(H2O)n ]^0 clusters.The results of hydration energy calculation suggest that the six-coordinated contact ion pair (CIP) is the stable configuration for small hydration clusters (n≤5),while the solvent-shared ion pair (SSIP) represents the favorable structure for medium hydration clusters (6≤n≤10).The solvent is separated by x water molecules (xSIP,x≥2 is the number of water molecule between Ni^2+ and SO4^2-) in larger hydration clusters (n≥11).The EXAFS analysis of the NiSO 4 aqueous solutions and NiSO4 ·6H2O solid established that Ni^2+ was surrounded by six water molecules tightly forming an octahedral structure in the first hydration shell,and no CIP was found from 0.70 mol/L to 2.22 mol/L (near saturation).The Ni-O distance and coordinated number were 2.040±0.020 and 6.0±1.0,respectively.These results are consistent with the DFT calculations for [NiSO4(H2O)n ]^0 clusters.DFT and EXAFS are powerful techniques that can be used to enhance the resolution of NiSO 4 solution microstructure.展开更多
The Co（II） complex I and ammonium salt II were synthesized from the direct reaction of 1,2-ethylenediamine and cobaltous acetate tetrahydrate and manganese acetate tetrahydrate in anhydrous ethanol. Treatment of N,N...The Co（II） complex I and ammonium salt II were synthesized from the direct reaction of 1,2-ethylenediamine and cobaltous acetate tetrahydrate and manganese acetate tetrahydrate in anhydrous ethanol. Treatment of N,N＇-bis（salicylidene）ethylenediamine with Cu（OAc）2·H2O results in the formation of Cu（II） complex III. C14H37CoNaO8 （I）： triclinic, space group P1, a = 8.6296（12）, b = 12.0291（17）, c = 12.1108（17） A, α = 75.335（2）, β = 69.991（2）, γ = 72.248（2）°, V= 1109.4（3） A3, Z = 2, ρcaloa = 1.342 g/cm3, the final R= 0.0342 for 4817 observed reflections with I 〉 2σ（I） and Rw = 0.1263 for all data. C6H16N204 （II）： space group P1, a = 5.5513（10）, b = 5.5589（11）, c = 7.4437（14） A, α = 94.332（4）, β = 104.497（4）, γ = 103.487（4）°,V= 214.06（7） A3, Z = 1, ρcalcd = 1.398 g/cm3, the final R = 0.0431 for 829 observed reflections with I〉 2σ（I） and Rw = 0.1263 for all data. C14H37CuN40 （III）, space group P21/n, a = 9.050（9）, b = 18.434（17）, c = 11.659（11） A, β = 107.134（19）°, V= 1859（3） A3, Z = 4, ρcalcd =1.443 g/cm3, the final R = 0.0616 for 3308 observed reflections （O 〉 2σ（I）） and Rw = 0.1229 for all data. Their structures were all determined by X-ray diffraction, elemental analysis and IR.展开更多
基金Project supported by the Natural Science Foundation of Tangshan Teacher’s College (No. 04C06)
文摘The stable configurations and hydrogen bond nature of （H2O）n clusters （n = 3-6） have been investigated by the B3LYP method at the 6-31＋＋g^＊＊ level. Upon calculation, four conclusions have been drawn： （1） In the （H2O）3-5 clusters, cyclic configurations were confirmed to be the most stable. But in the （H2O）3-4 ones, only cyclic configurations could be observed. From n = 5 （（H2O）5 clusters）, three-dimensional configuration could be found： （2） In the （H2O）6 clusters, all configurations are inclined to be three-dimensional except the most stable configuration which is cyclic; （3） The stable order of （H2O）6 clusters indicates that it is the arrangement of hydrogen bond that plays a decisive role in the cluster stabilities, the zero-point energy is also important, and cluster stabilities are independent on the number of hydrogen bonds; （4） There exist strong cooperativity and superadditivity in the （H2O）n clusters.
基金Nature Science Foundation of Qinghai Province(2018-ZJ-945Q)NSFC(21573268)+1 种基金Joint Foundation of Salt Lake Chemical(U1607106)Instrument function development and technology innovation project of Chinese academy of sciences(2018g108)
文摘The microhydration structure of nickel sulfate aqueous solution has been determined via density functional theory (DFT) calculation and extended X-ray absorption fine structure (EXAFS) spectroscopy.The geometric optimization and energy calculation of nickel sulfate hydrated clusters of the molecular formula [NiSO4(H2O)n ]^0 (n=1-12) were determined via DFT using the B3LYP method.Several possible initial structures were considered for clusters of each size to locate the equilibrium geometry.Based on the DFT calculation,the favorable structure of Ni^2+ includes the six-coordinated form of [NiSO4(H2O)n ]^0 clusters.The results of hydration energy calculation suggest that the six-coordinated contact ion pair (CIP) is the stable configuration for small hydration clusters (n≤5),while the solvent-shared ion pair (SSIP) represents the favorable structure for medium hydration clusters (6≤n≤10).The solvent is separated by x water molecules (xSIP,x≥2 is the number of water molecule between Ni^2+ and SO4^2-) in larger hydration clusters (n≥11).The EXAFS analysis of the NiSO 4 aqueous solutions and NiSO4 ·6H2O solid established that Ni^2+ was surrounded by six water molecules tightly forming an octahedral structure in the first hydration shell,and no CIP was found from 0.70 mol/L to 2.22 mol/L (near saturation).The Ni-O distance and coordinated number were 2.040±0.020 and 6.0±1.0,respectively.These results are consistent with the DFT calculations for [NiSO4(H2O)n ]^0 clusters.DFT and EXAFS are powerful techniques that can be used to enhance the resolution of NiSO 4 solution microstructure.
文摘The Co（II） complex I and ammonium salt II were synthesized from the direct reaction of 1,2-ethylenediamine and cobaltous acetate tetrahydrate and manganese acetate tetrahydrate in anhydrous ethanol. Treatment of N,N＇-bis（salicylidene）ethylenediamine with Cu（OAc）2·H2O results in the formation of Cu（II） complex III. C14H37CoNaO8 （I）： triclinic, space group P1, a = 8.6296（12）, b = 12.0291（17）, c = 12.1108（17） A, α = 75.335（2）, β = 69.991（2）, γ = 72.248（2）°, V= 1109.4（3） A3, Z = 2, ρcaloa = 1.342 g/cm3, the final R= 0.0342 for 4817 observed reflections with I 〉 2σ（I） and Rw = 0.1263 for all data. C6H16N204 （II）： space group P1, a = 5.5513（10）, b = 5.5589（11）, c = 7.4437（14） A, α = 94.332（4）, β = 104.497（4）, γ = 103.487（4）°,V= 214.06（7） A3, Z = 1, ρcalcd = 1.398 g/cm3, the final R = 0.0431 for 829 observed reflections with I〉 2σ（I） and Rw = 0.1263 for all data. C14H37CuN40 （III）, space group P21/n, a = 9.050（9）, b = 18.434（17）, c = 11.659（11） A, β = 107.134（19）°, V= 1859（3） A3, Z = 4, ρcalcd =1.443 g/cm3, the final R = 0.0616 for 3308 observed reflections （O 〉 2σ（I）） and Rw = 0.1229 for all data. Their structures were all determined by X-ray diffraction, elemental analysis and IR.
