The bimetallic hexanuclear cluster [Mn4Ni2O2（Cl-Sao）6.（CH3OH）8].10CH3OH （1） was synthesized. Single-crystal X-ray analysis reveals that 1 consists of two [Mn2Ni（μ3-O）（Cl-Sao）3] subunits linked together via ...The bimetallic hexanuclear cluster [Mn4Ni2O2（Cl-Sao）6.（CH3OH）8].10CH3OH （1） was synthesized. Single-crystal X-ray analysis reveals that 1 consists of two [Mn2Ni（μ3-O）（Cl-Sao）3] subunits linked together via two pairs of long Ni-O bonds involving two oximate oxygen atoms and two phenolate oxygen atoms. Each Mn and Ni center achieves six-coordination with axial methanol molecules. The spin centers of the Mnm and Niu ions exchange magnetic coupling through O2-, O-phenolate and -N-O- bridges. The magnetic properties of the cluster have been investigated.展开更多
The lowest-energy structures and properties of neutral nickel clusters Nin（n=31―35） were studied by a combination method of genetic algorithm（GA） searching with a tight-binding potential and the density functiona...The lowest-energy structures and properties of neutral nickel clusters Nin（n=31―35） were studied by a combination method of genetic algorithm（GA） searching with a tight-binding potential and the density functional theory（DFT） calculations.Structural candidates obtained from our GA search were further optimized with first-principles calculations.Four typical isomers of lower-energy neutral Nin（n=31―35） clusters were shown,as well as their binding energies per atom（Eb）,second differences in energy and magnetic moment.The medium-sized nickel clusters in a size range from 31 atoms to 35 atoms were found to favor the distorted double-icosahedron-like structures.The fragments composed of the central atoms appear as some small stable clusters.展开更多
Based on spin-polarized density functional theory (DFT) calculations, the interaction between nickel cluster decorated single-wall carbon nanotube (CNT) and CO molecule has been investigated. DFT calculations are perf...Based on spin-polarized density functional theory (DFT) calculations, the interaction between nickel cluster decorated single-wall carbon nanotube (CNT) and CO molecule has been investigated. DFT calculations are performed with generalized gradient approximation (GGA) using Perdew-Burke-Ernzerhof (PBE) functional. Interaction of CNT and cluster induces spin polarization in the CNT. Nickel decorated CNT has a large magnetic moment of 4.00 μB which decreases to 0.10 μB when CO molecule is absorbed to it. Such a drastic reduction in magnetization may be detected by SQUID magnetometer. Hence by measuring magnetization change, CNT-cluster system may be used as gas detectors. The charge transfer between the systems has been discussed through Mulliken charge analysis for different orientations of the adsorbed CO molecule. We observed that CNT-cluster system acts as electron donor and CO molecule acts as electron acceptor in this study.展开更多
Two mononuclear metal-organic complexes, [Co（Hmpdc）2（H2O）4]·4H2O 1 and [Ni（Hfmpdc）2（H2O）4]·6H2O 2, were prepared from 2,6-dimethylpyridine-3,5-dicarboxylic acid （Hzmpdc） and 4-furyl-2,6-dimethylpyr...Two mononuclear metal-organic complexes, [Co（Hmpdc）2（H2O）4]·4H2O 1 and [Ni（Hfmpdc）2（H2O）4]·6H2O 2, were prepared from 2,6-dimethylpyridine-3,5-dicarboxylic acid （Hzmpdc） and 4-furyl-2,6-dimethylpyridine-3,5-dicarboxylic acid （H2fmpdc） with M（NO3）2 salts, respectively, and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectroscopy, and photoluminescent measurement. Complex 1 crystallizes in triclinic, space group P1 with a = 7.634（5）, b = 8.695（5）, c = 10.757（6）A, α = 69.647（7）, β = 69.957（8）, γ = 83.733（7）°, V = 628.9（7）A^3, Dc = 1. 561 g/cm^3,μ（MoKa） = 0.763 mm^-1, F（000） = 309, Z = 1, the final R = 0.0553 and wR = 0.1469 for 1909 observed reflections （Ⅰ 〉 2σ（Ⅰ））. Complex 2 crystallizes in monoclinic, space group P21/n with a = 9.5934（16）, b = 12.422（2）, c = 14.826（3） A, β = 105.201（2）°, V = 1705.0（5）A3, Dc = 1. 479 g/cm^3,μ（MoKa） = 0.655 mm^-1, F（000） = 796, Z = 2, the final R= 0.0351 and wR = 0.0889 for 2387 obsevved reflections （Ⅰ 〉 2σ（Ⅰ））. In the crystal structures of 1 and 2, diverse supramolecular motifs from 1-D chains/ladders to 3-D networks are constructed from corresponding distinct [M^Ⅱ（H2O）8] ion clusters as the second building units, respectively. The solid state compounds of 1 and 2 show similar photoluminescent spectra with emission maximum at ca.展开更多
降低芯片背面金属-半导体欧姆接触电阻是有效提高器件性能的方式之一。采用650 V SiC肖特基势垒二极管(SBD)工艺,使用波长355 nm不同能量的脉冲激光进行退火实验,利用X射线衍射(XRD)和探针台对晶圆背面镍硅合金进行测量分析,得出最佳能...降低芯片背面金属-半导体欧姆接触电阻是有效提高器件性能的方式之一。采用650 V SiC肖特基势垒二极管(SBD)工艺,使用波长355 nm不同能量的脉冲激光进行退火实验,利用X射线衍射(XRD)和探针台对晶圆背面镍硅合金进行测量分析,得出最佳能量为3.6 J/cm^(2)。退火后采用扫描电子显微镜(SEM)观察晶圆背面碳团簇,针对背面的碳团簇问题,在Ar;气氛下对晶圆进行了表面处理,使用SEM和探针台分别对两组样品的表面形貌和电压-电流特性进行了对比分析。实验结果表明,通过表面处理可以有效降低表面的碳含量,并且使器件正向压降均值降低了6%,利用圆形传输线模型(CTLM)测得芯片的比导通电阻为9.7×10^(-6)Ω·cm^(2)。器件性能和均匀性都得到提高。展开更多
用非限制性密度泛函方法UBP86泛函结合def2-TZVP基组获得了Ni2～6团簇的几何结构并用ELF(ElectronLocalized Function)和LOL(Localized Orbital Locator)函数对小镍团簇的电子结构进行拓扑分析.研究结果表明,除Ni2团簇外,团簇中Ni—Ni...用非限制性密度泛函方法UBP86泛函结合def2-TZVP基组获得了Ni2～6团簇的几何结构并用ELF(ElectronLocalized Function)和LOL(Localized Orbital Locator)函数对小镍团簇的电子结构进行拓扑分析.研究结果表明,除Ni2团簇外,团簇中Ni—Ni键的成键临界点不在键轴上,为弯曲键.镍团簇中Ni—Ni间的金属键为部分共价键,其价层Basin的布局数均小于1e,并且团簇中存在多个多中心价层Basin.团簇中各个化学键均强烈离域化.团簇中的单电子主要位于内层轨道,并没有参与成键.展开更多
The double crown hexakis[(di-μ-benzylthio)nickel]cluster,[Ni_(6)(SCH_(2)C_(6)H_(5))_(12)]·C_(2)H_(5)OH,was obtained by reacting C_(6)H_(5)CH_(2)SNa with[(CH_(3))_(2)CHOCS_(2)]_(2)Ni in EtOH.The results of electr...The double crown hexakis[(di-μ-benzylthio)nickel]cluster,[Ni_(6)(SCH_(2)C_(6)H_(5))_(12)]·C_(2)H_(5)OH,was obtained by reacting C_(6)H_(5)CH_(2)SNa with[(CH_(3))_(2)CHOCS_(2)]_(2)Ni in EtOH.The results of electrochemical studies show that[Ni_(6)(SCH_(2)C_(6)H_(5))_(12)]is a quasi-reversible process.The crystal structure of[Ni_(6)(SCH_(2)C_(6)H_(5))_(12)]·C_(2)H_(5)OH is composed of discrete[Ni_(6)(SCH_(2)C_(6)H_(5))_(12)]and C_(2)H_(5)OH solvent molecules.Each Ni atom is surrounded by four S atoms of theµ2-SCH_(2)C_(6)H_(5)ligands in a distorted square-planar structure.The C_(6)H_(5)CH_(2)S-side chains are arranged in the axial and equatorial positions,alternately,concerning the pseudo-hexagonal axis of the molecule.Strongπ-πand C-H···πeffects form the supramolecular nano-channel along the a-axis in the crystal,which wraps the solvent ethanol molecules in it.In addition,a wall is formed along the b-and c-axes,so that the ethanol molecules can freely enter and leave along the a-axis.These effects result in the ability of the title compound to adsorb and desorb ethanol molecules.Thermogravimetric analysis and powder X-ray diffraction at different temperature are provided to demonstrate this point.展开更多
Two primitive metal-organic frameworks(MOFs),Ni L1 and Ni L2,based on Ni_(8)O_(6)-cluster and ditopic pyrazolate linkers,L1(with rigid alkyne arms)and L2(with flexible alkyne chains),were prepared.The proton conductiv...Two primitive metal-organic frameworks(MOFs),Ni L1 and Ni L2,based on Ni_(8)O_(6)-cluster and ditopic pyrazolate linkers,L1(with rigid alkyne arms)and L2(with flexible alkyne chains),were prepared.The proton conductivities of these MOFs in pristine form and imidazole-encapsulated forms,Im@Ni L1 and Im@Ni L2,were measured and compared.Upon introduction of imidazole molecules,the proton conductivity could be increased by 3 to 5 orders of magnitude and reached as high as 1.72×10^(-2)S/cm(at 98%RH and 80℃).Also,whether imidazole molecules were introduced or not,Ni_(8)O_(6)-based MOFs with L2 in general gave better proton conductivity than those with L1 signifying that flexible side arms indeed assist proton conduction probably via establishment of efficient proton-conducting channels along with formation of highly ordered domains of water/imidazole molecules within the network cavities.Beyond the active Ni_(8)O_(6)-cluster,tuning flexibility of linker pendants serves as an alternative approach to regulate/modulate the proton conductivity of MOFs.展开更多
Nickel-based single-crystal superalloys are the key materials for the manufacturing and development of advanced aeroengines. Rhenium is a crucial alloying element in the advanced nickel-based single-crystal superalloy...Nickel-based single-crystal superalloys are the key materials for the manufacturing and development of advanced aeroengines. Rhenium is a crucial alloying element in the advanced nickel-based single-crystal superalloys for its special strengthening effects. The addition of Re could effectively enhance the creep properties of the single-crystal superalloys; thus, the content of Re is considered as one of the characteristics in different-generation single-crystal superalloys. Owing to the fundamental importance of rhenium to nickel-based single-crystal superalloys, much progress has been made on understanding of the effect of rhenium in the single-crystal superalloys. While the effect of Re doping on the nickelbased superalloys is well documented, the origins of the socalled rhenium effect are still under debate. In this paper,the effect of Re doping on the single-crystal superalloys and progress in understanding the rhenium effect are reviewed. The characteristics of the d-states occupancy in the electronic structure of Re make it the slowest diffusion elements in the single-crystal superalloys, which is undoubtedly responsible for the rhenium effect, while the postulates of Re cluster and the enrichment of Re at the c/c0 interface are still under debate, and the synergistic action of Re with other alloying elements should be further studied.Additionally, the interaction of Re with interfacial dislocations seems to be a promising explanation for the rhenium effect. Finally, the addition of Ru could help suppress topologically close-packed（TCP） phase formation and strengthen the Re doping single-crystal superalloys.Understanding the mechanism of rhenium effect will be beneficial for the effective utilization of Re and the design of low-cost single-crystal superalloys.展开更多
The title compound, [NiL]5[V34O82·8H2O （1, L=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane）, has been synthesized under hydrothermal conditions and structurally characterized by EA, IR, XPS, TG an...The title compound, [NiL]5[V34O82·8H2O （1, L=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane）, has been synthesized under hydrothermal conditions and structurally characterized by EA, IR, XPS, TG and single-crystal X-ray diffraction. It crystallizes in the monoclinic system, space group C2/c with a=33.061（4）, b=15.3457（17）, c=33.902（4）, β=101.930（2）°, Mr=4904.08, V=16828（3）3 , Z=4, Dc=1.936 g/cm3 , F（000）=9832, μ=2.425 mm-1 , the final R=0.0402 and wR=0.0969. The mixed valence vanadium clusters of [V34O82]10- bridges [NiL]2＋ to form a one-dimensional chain in 1. To the best of our knowledge, the title complex is the first example of organic-inorganic hybrid material involving the largest vanadium cluster of [V34O82]10-.展开更多
基金support from the Natural Science Foundation of China(NSFC)(No.21171021)Beijing National Laboratory for Molecular Sciences(BNLMS)Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘The bimetallic hexanuclear cluster [Mn4Ni2O2（Cl-Sao）6.（CH3OH）8].10CH3OH （1） was synthesized. Single-crystal X-ray analysis reveals that 1 consists of two [Mn2Ni（μ3-O）（Cl-Sao）3] subunits linked together via two pairs of long Ni-O bonds involving two oximate oxygen atoms and two phenolate oxygen atoms. Each Mn and Ni center achieves six-coordination with axial methanol molecules. The spin centers of the Mnm and Niu ions exchange magnetic coupling through O2-, O-phenolate and -N-O- bridges. The magnetic properties of the cluster have been investigated.
基金Supported by the National Natural Science Foundation of China(Nos.21043001 and 20773047)
文摘The lowest-energy structures and properties of neutral nickel clusters Nin（n=31―35） were studied by a combination method of genetic algorithm（GA） searching with a tight-binding potential and the density functional theory（DFT） calculations.Structural candidates obtained from our GA search were further optimized with first-principles calculations.Four typical isomers of lower-energy neutral Nin（n=31―35） clusters were shown,as well as their binding energies per atom（Eb）,second differences in energy and magnetic moment.The medium-sized nickel clusters in a size range from 31 atoms to 35 atoms were found to favor the distorted double-icosahedron-like structures.The fragments composed of the central atoms appear as some small stable clusters.
文摘Based on spin-polarized density functional theory (DFT) calculations, the interaction between nickel cluster decorated single-wall carbon nanotube (CNT) and CO molecule has been investigated. DFT calculations are performed with generalized gradient approximation (GGA) using Perdew-Burke-Ernzerhof (PBE) functional. Interaction of CNT and cluster induces spin polarization in the CNT. Nickel decorated CNT has a large magnetic moment of 4.00 μB which decreases to 0.10 μB when CO molecule is absorbed to it. Such a drastic reduction in magnetization may be detected by SQUID magnetometer. Hence by measuring magnetization change, CNT-cluster system may be used as gas detectors. The charge transfer between the systems has been discussed through Mulliken charge analysis for different orientations of the adsorbed CO molecule. We observed that CNT-cluster system acts as electron donor and CO molecule acts as electron acceptor in this study.
基金supported by the NNSFC (No. 20701041)the Key Project of Chinese Ministry of Education (No. 208116)+1 种基金the Natural Science Foundation of CQ CSTC (No. 2007BB5228)the Scientific and Technological Project of CQEC (No. KJ080829).
文摘Two mononuclear metal-organic complexes, [Co（Hmpdc）2（H2O）4]·4H2O 1 and [Ni（Hfmpdc）2（H2O）4]·6H2O 2, were prepared from 2,6-dimethylpyridine-3,5-dicarboxylic acid （Hzmpdc） and 4-furyl-2,6-dimethylpyridine-3,5-dicarboxylic acid （H2fmpdc） with M（NO3）2 salts, respectively, and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectroscopy, and photoluminescent measurement. Complex 1 crystallizes in triclinic, space group P1 with a = 7.634（5）, b = 8.695（5）, c = 10.757（6）A, α = 69.647（7）, β = 69.957（8）, γ = 83.733（7）°, V = 628.9（7）A^3, Dc = 1. 561 g/cm^3,μ（MoKa） = 0.763 mm^-1, F（000） = 309, Z = 1, the final R = 0.0553 and wR = 0.1469 for 1909 observed reflections （Ⅰ 〉 2σ（Ⅰ））. Complex 2 crystallizes in monoclinic, space group P21/n with a = 9.5934（16）, b = 12.422（2）, c = 14.826（3） A, β = 105.201（2）°, V = 1705.0（5）A3, Dc = 1. 479 g/cm^3,μ（MoKa） = 0.655 mm^-1, F（000） = 796, Z = 2, the final R= 0.0351 and wR = 0.0889 for 2387 obsevved reflections （Ⅰ 〉 2σ（Ⅰ））. In the crystal structures of 1 and 2, diverse supramolecular motifs from 1-D chains/ladders to 3-D networks are constructed from corresponding distinct [M^Ⅱ（H2O）8] ion clusters as the second building units, respectively. The solid state compounds of 1 and 2 show similar photoluminescent spectra with emission maximum at ca.
文摘降低芯片背面金属-半导体欧姆接触电阻是有效提高器件性能的方式之一。采用650 V SiC肖特基势垒二极管(SBD)工艺,使用波长355 nm不同能量的脉冲激光进行退火实验,利用X射线衍射(XRD)和探针台对晶圆背面镍硅合金进行测量分析,得出最佳能量为3.6 J/cm^(2)。退火后采用扫描电子显微镜(SEM)观察晶圆背面碳团簇,针对背面的碳团簇问题,在Ar;气氛下对晶圆进行了表面处理,使用SEM和探针台分别对两组样品的表面形貌和电压-电流特性进行了对比分析。实验结果表明,通过表面处理可以有效降低表面的碳含量,并且使器件正向压降均值降低了6%,利用圆形传输线模型(CTLM)测得芯片的比导通电阻为9.7×10^(-6)Ω·cm^(2)。器件性能和均匀性都得到提高。
文摘用非限制性密度泛函方法UBP86泛函结合def2-TZVP基组获得了Ni2～6团簇的几何结构并用ELF(ElectronLocalized Function)和LOL(Localized Orbital Locator)函数对小镍团簇的电子结构进行拓扑分析.研究结果表明,除Ni2团簇外,团簇中Ni—Ni键的成键临界点不在键轴上,为弯曲键.镍团簇中Ni—Ni间的金属键为部分共价键,其价层Basin的布局数均小于1e,并且团簇中存在多个多中心价层Basin.团簇中各个化学键均强烈离域化.团簇中的单电子主要位于内层轨道,并没有参与成键.
基金supported by the Research Initiation Fund for Distinguished Professors (13510007) of Henan University of Science and Technology and Luoyang Heluo Talents Plan Fund
文摘The double crown hexakis[(di-μ-benzylthio)nickel]cluster,[Ni_(6)(SCH_(2)C_(6)H_(5))_(12)]·C_(2)H_(5)OH,was obtained by reacting C_(6)H_(5)CH_(2)SNa with[(CH_(3))_(2)CHOCS_(2)]_(2)Ni in EtOH.The results of electrochemical studies show that[Ni_(6)(SCH_(2)C_(6)H_(5))_(12)]is a quasi-reversible process.The crystal structure of[Ni_(6)(SCH_(2)C_(6)H_(5))_(12)]·C_(2)H_(5)OH is composed of discrete[Ni_(6)(SCH_(2)C_(6)H_(5))_(12)]and C_(2)H_(5)OH solvent molecules.Each Ni atom is surrounded by four S atoms of theµ2-SCH_(2)C_(6)H_(5)ligands in a distorted square-planar structure.The C_(6)H_(5)CH_(2)S-side chains are arranged in the axial and equatorial positions,alternately,concerning the pseudo-hexagonal axis of the molecule.Strongπ-πand C-H···πeffects form the supramolecular nano-channel along the a-axis in the crystal,which wraps the solvent ethanol molecules in it.In addition,a wall is formed along the b-and c-axes,so that the ethanol molecules can freely enter and leave along the a-axis.These effects result in the ability of the title compound to adsorb and desorb ethanol molecules.Thermogravimetric analysis and powder X-ray diffraction at different temperature are provided to demonstrate this point.
基金the National Natural Science Foundation of China(No.21871061)the Foundation of Basic and Applied Basic Research of Guangdong Province(No.2021A1515010274)+2 种基金the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01Z032)the Science and Technology Planning Project of Guangdong Province(No.2021A0505030066)the Science and Technology Program of Guangzhou(No.201807010026)。
文摘Two primitive metal-organic frameworks(MOFs),Ni L1 and Ni L2,based on Ni_(8)O_(6)-cluster and ditopic pyrazolate linkers,L1(with rigid alkyne arms)and L2(with flexible alkyne chains),were prepared.The proton conductivities of these MOFs in pristine form and imidazole-encapsulated forms,Im@Ni L1 and Im@Ni L2,were measured and compared.Upon introduction of imidazole molecules,the proton conductivity could be increased by 3 to 5 orders of magnitude and reached as high as 1.72×10^(-2)S/cm(at 98%RH and 80℃).Also,whether imidazole molecules were introduced or not,Ni_(8)O_(6)-based MOFs with L2 in general gave better proton conductivity than those with L1 signifying that flexible side arms indeed assist proton conduction probably via establishment of efficient proton-conducting channels along with formation of highly ordered domains of water/imidazole molecules within the network cavities.Beyond the active Ni_(8)O_(6)-cluster,tuning flexibility of linker pendants serves as an alternative approach to regulate/modulate the proton conductivity of MOFs.
基金financially supported by the National Basic Research Program of China(No.2009CB623701)the National Natural Science Foundation of China(Nos.11374174,50971075 and 51390471)
文摘Nickel-based single-crystal superalloys are the key materials for the manufacturing and development of advanced aeroengines. Rhenium is a crucial alloying element in the advanced nickel-based single-crystal superalloys for its special strengthening effects. The addition of Re could effectively enhance the creep properties of the single-crystal superalloys; thus, the content of Re is considered as one of the characteristics in different-generation single-crystal superalloys. Owing to the fundamental importance of rhenium to nickel-based single-crystal superalloys, much progress has been made on understanding of the effect of rhenium in the single-crystal superalloys. While the effect of Re doping on the nickelbased superalloys is well documented, the origins of the socalled rhenium effect are still under debate. In this paper,the effect of Re doping on the single-crystal superalloys and progress in understanding the rhenium effect are reviewed. The characteristics of the d-states occupancy in the electronic structure of Re make it the slowest diffusion elements in the single-crystal superalloys, which is undoubtedly responsible for the rhenium effect, while the postulates of Re cluster and the enrichment of Re at the c/c0 interface are still under debate, and the synergistic action of Re with other alloying elements should be further studied.Additionally, the interaction of Re with interfacial dislocations seems to be a promising explanation for the rhenium effect. Finally, the addition of Ru could help suppress topologically close-packed（TCP） phase formation and strengthen the Re doping single-crystal superalloys.Understanding the mechanism of rhenium effect will be beneficial for the effective utilization of Re and the design of low-cost single-crystal superalloys.
基金supported by the Science and Technology Planning Project of Hunan Province (2012FJ3050, 2012NK3067)the Construct Program of the Key Discipline in Hunan Province (2011–76)the Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province (2012–318)
文摘The title compound, [NiL]5[V34O82·8H2O （1, L=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane）, has been synthesized under hydrothermal conditions and structurally characterized by EA, IR, XPS, TG and single-crystal X-ray diffraction. It crystallizes in the monoclinic system, space group C2/c with a=33.061（4）, b=15.3457（17）, c=33.902（4）, β=101.930（2）°, Mr=4904.08, V=16828（3）3 , Z=4, Dc=1.936 g/cm3 , F（000）=9832, μ=2.425 mm-1 , the final R=0.0402 and wR=0.0969. The mixed valence vanadium clusters of [V34O82]10- bridges [NiL]2＋ to form a one-dimensional chain in 1. To the best of our knowledge, the title complex is the first example of organic-inorganic hybrid material involving the largest vanadium cluster of [V34O82]10-.
