Bridging complexes of rare earth and cobalt cluster as catalyst precursors for Fischer-Tropsch synthesis

Three new bridging complexes of rare earth and cobalt cluster were synthesized and characterized via ICP, IR and TG techniques. The structure of the complexes was speculated as： two rare earth atoms were bridged with four CF3COO–, and rare earth atoms were coordinated with cobalt carbonyl clusters to form a steady structure. Application of the complexes as the catalyst precursors was explored for Fischer-Tropsch synthesis. The study showed that the bridging complexes of rare earth and cobalt cluster had large molecular size and were difficult to enter pore path of γ-Al2O3, so they were dispersed on the surface of γ-Al2O3 support. In addition, the performance of Co（Ce）/ γ-Al2O3 was the best among the catalysts with complex as precursor and maintained 77.7% CO conversion at 220 oC for 80 operation hours.

Size-dependent dissociation of small cobalt clusters on ultrathin NaCI films

Mass-selected anionic cobalt clusters of two different sizes （Co2 and Co13） were deposited onto ultrathin NaC1 films grown on an Au（111） substrate. Using scanning tunneling microscopy experiments and density functional theory simulations, we show that the deposited Co2 cluster dissociates and that the resulting Co atoms dope the NaCI surface by substituting Na ions. In contrast, the larger Co13 cluster does not dissociate and remains stable on top of the NaC1 film. The size- dependent fragmentation of clusters is an important aspect in the understanding of the chemical interaction between size-selected small aggregates of atoms and supporting surfaces.

Synthesis of Polymer-Supported Heteronuclear Rhodium- Cobalt Bimetallic Carbonyl Cluster Catalysts and Their Hydroformylation Properties

Tetranuclear Rh-Co bimetallic cluster was synthesized and characterized by IR and XPS. The properties of the anchored catalysts, its stability and the ligand effect were also studied. The experimental results show that the optimal conditions for the hydroformylation of hexene-1 are as follows: the temperature is 80℃, reaction time 8 h, pressure 5. 88×105 Pa, and molar ratio of H2/CO 1. 2/1. 0. Functional groups attached to the donor atom(N) possess more or less some influence on the catalytic behavior. Compared with the homogeneous cluster, the polymer-supported bimetallic cluster is more stable. After the catalytic reaction, the structure of the anchored catalysts was not destroyed. X-ray photoelectron spectroscopy characterization indicates that there is a weak interaction between the polymer support and the active metals.

Distinct Hydrogen-bonded M~Ⅱ(H_2O)_8 Clusters as Second Building Units for 1-D, 2-D and 3-D Supramolecular Architectures (M=Cobalt and Nickel)

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.

Quasi0—aromaticity in Cluster Chemistry III.Localized Molecular Orbita

The localized molecular orbitals and energy levels for [Co_6 (μ_3-S)_8 (PH_3)_6]￣(n+)(n=0, 1) as model molecules of the electron-rich [Co_6 (μ_3-S)_8 (PPh_3)_6]￣(n+) (n=0,1) cluster compounds have been calculated by using Edmiston-Ruedenberg energy localization scheme under the spin-unrestricted CNDO/2 approximation. It is shown that the cluster skeletons of these two isostructural molecules consist of the edge-localized two-centered two-electron (Co-S) bonds plus a pair of the skeleton electrons delocalized on the whole cluster core,leading an extra stability of the cluster core.The one-electron oxidation for the neutral molecule gives rise to a one-electron σ (Co-Co) bond.which further resonates among the three diagonal lines of the {Co_6} octahedron. The comparison between [Co_6 (μ_3-S)_8(PPh_3)_6] and [Co_6(μ_3-CO)_8(CO)_6]￣(4-) indicates that the latter possesses face-localized bridging-bonds which are further delocalized on the whole surface of the cluster octahedron by the back-donation bonds from the lone electron pairs on the Co atoms to the capping carbonyl CO ligands. The structural features of the series of the [Co6(μ_3-X)_8L_6]￣(n+)(X =S, Se; L=PPh_3,PEt_3, CO;n=0, 1) cluster compounds are briefly rationalized on the basis of the localization description as well.

Structural,Electronic and Magnetic Properties of ConO(n=2-10)Clusters:A Density Functional Study

The structural, electronic, and magnetic properties of ConO （n = 2- 10） clusters have been systematically investigated within the framework of the generalized gradient approximation density functional theory. The results indicate that the O atom occupies the surface-capped position on ConO （n = 2-10） clusters. The stabilities of the host clusters are improved by adding one O atom. Maximum peaks of the second-order difference energy of the ground-state ConO clusters are found at n = 3, 6 and 8, indicating higher stability than their neighboring clusters. Compared with corresponding pure Con clusters, the O-doped cobalt clusters have larger gaps between the HOMO and LUMO energy levels, indicating their higher chemical stabilities. In addition, the doping of O atom exhibits different influence on the magnetism of the clusters. This is also further investigated by the local magnetic moment, deformation charge density and partial local density of states analysis.

Synthesis and Characterization of Linked Clusters Capped by Alkylidyne

The lsolobal displacement reaction between the dianion {M(CO)3[(h5-C5H4) C(O)C6H4C(O)(h5-C5H4)](CO)3M}2- and two molecules of [(m3-C)CO2Et]Co3(CO)9 gave rise to the formation of terephthaloyl(biscyclopentadienyl)-bridged double cluster complexes [(h5-C5H4)C(O)C6H4C(O)(h5-C5H4)]{[(m3-C)CO2Et]Co2M(CO)8}2 (M = Mo 1, M = W, 2). In the reaction, single cluster complexes[(m3-C)CO2Et]-Co2M(CO)8[h5-C5H4C(O)C6H4CO2CH3] ( M = Mo 3, M = W, 4) were yielded as by-products. All the cluster complexes were characterized by C/H analysis, IR and 1H NMR spectroscopy, and the structure of 3 has been determined by single-crystal X-ray diffraction method. Crystal data: Mr = 750.19, monoclinic, space group P21/c, a = 22.652(5), b = 8.954 (2), c = 14.530(3) ? b = 104.00(3), V = 2859.6(10) 懦, Z = 4, Dc = 1.743 mg/m? F(000) = 1488, m = 1.644 mm-1, the final R = 0.0555 and wR = 0.1353 for 5519 observations with I > 2s(I).

Synthesis and Characterization of Rh-Co Butterfly Clusters Capped by Functionally Substituted 1-Alkynes

By the reactions of [Rh2Co2(CO)12] 1 with functionally substituted alkyne ligands HC≡CR 2 (R = FeCp2) and 3 (R = 2-OH-C6H4COOCH2), respectively in n-hexane at room temperature, two new cluster derivatives [Rh2Co2(CO)6(-CO)4(4, 2-HC≡CR)] 4 (R = FeCp2) and 5 (R = 2-OH-C6H4COOCH2) were obtained respectively. The alkyne was inserted into the CoCo bond of cluster 1 to give two butterfly clusters. Cluster 4 has been determined by single-crystal X-ray diffraction. Crystallographic data: C22H10Co2FeO10Rh2, Mr = 813.83, orthorhombic, space group P212121, a = 11.5318(7), b = 12.6572(7), c = 17.018(1) ? V = 2483.9(3) 3, Z = 4, Dc = 2.176 g/cm3, F(000) = 1568, = 3.233 mm-1, the final R = 0.0366 and wR = 0.0899 for 5367 observed reflections with I > 2(I). The two clusters have also been characterized by elemental analysis, IR and 1H-NMR spectroscopy.

杂原子掺杂钴钼氧化物复合材料的制备及电催化性能研究

利用水热合成的方式,将钴钼氧化物材料均匀地负载于碳布表面,对所得材料进行N化、P化,探究不同复合材料的电催化水分解性能,进一步探究不同杂原子的引入对于材料的电催化性能的影响。同时,利用Keggin型多金属氧酸簇(H_(3)O_(4)0PW_(12)·xH_(2)O)对CoMoOx进行掺杂,探究多金属氧簇的引入对于复合材料电催化性能的影响。研究发现,P化过后的复合材料具有优异的电化学活性,析氧反应中在电流密度为10 mA·cm^(-2)时的过电位为313 mV,析氢反应中电流密度为10 mA·cm^(-2)时的过电位为197 mV。优异的电催化性能归因于P元素的引入改善了复合材料的电子结构,促进活性位点对于活性中间体的吸附,进而促进电催化水分解过程的进行。本研究对于复合材料的优化条件进行探索,为电催化剂的改性提供了有效的策略。

Mo（W）－Co（Ni，Fe）簇合物的加氢脱硫催化活性

对线型、立方烷型和笼状３种不同构型的Ｍｏ（Ｗ）－Ｃｏ（Ｎｉ，Ｆｅ）－Ｓ（Ｏ）簇共１２种化合物进行了噻吩加氢脱硫和环己烯加氢的催化活性研究．讨论了簇合物的组成，金属原子的配比、价态与催化活性的关系．探讨了不同构型对活性的影响．

Co_3(CO)_7(μ_3-S)[μ, η~2-SCNC (O)C (R_1) (R_2)N (COR_3)]的合成和晶体结构

Co2（CO8）分别与4种硫代乙内酰脲S＝CNHC（O）C（R1）（R2）N（COR3）反应，得到4个新的含硫代乙内酰脲桥基双齿配位的三核钴羰基硫簇合物．用元素分析、IR、1HNMR和MS等手段表征了它们的结构，用X射线衍射测定了其中一个簇合物CO3（CO）7（μ3－S）［μ，η2－SCNC（O）C（CH3）（CH3）N（COCH3）］（IV）的晶体结构，晶体属三斜晶系，P1空间群，晶胞参数：a＝0．8456（3）nm，b＝1．1534（3）nm，c＝1．1990（4）nm；a＝107．36（3）°，β＝108．44（5）°，γ＝90．18（3）°；V＝1．052（6）nm3，Z＝2，F（000）＝584，Dc＝1．86g／cm3，μ＝25．71cm－1，最终偏离因子R＝0．046，Rw＝0．058．

钴原子簇化合物研究(Ⅳ)——含桥基杂环硫代酰胺基和杂环卡宾的三核钴羰基硫簇合物的合成及表征

用Co_2(CO)_3和杂环硫代酰胺SCXCH_2CH_2NH(X=NH,S,O)反应,得到两类6个新的可能具有手征性的三核钴羰基硫簇合物Co_3(CO)_7(μ_3-S)(μ-SCXCH_2CH_2N)(Ⅰ)和Co_3(CO))_6(μ_3-S)(:CXCH_2CH_2NH)(μ-SCXCH_2N)(Ⅱ).Ⅰ和Ⅱ的分子骨架Co_3S为四面体结构,其中SCXCH_2CH_2NH是通过S、N与2个Co键合的3e桥基配体,而:CXCH_2CH_2NH为2e杂环卡宾配体,对6个簇合物进行了表征,并对反应条件做了初步研究。

钴硫团簇Co_nS_(n-1)^+(n=2,3)的结构和稳定性

用 ab initio分子轨道方法 (RHF,U HF)和密度泛函 (DFT)方法研究了团簇 Co2 S+ ,Co3 S+ 2的各种可能的几何构型和电子结构 ,并计算了相应的较稳定构型的振动光谱 ,发现 Co2 S+ 和Co3 S+ 2 团簇最稳定结构均具有 Cs对称性 .

中西太平洋海山形态类型与钴结壳资源分布关系

通过对中西太平洋海山形态剖面的山体高度、山顶直径、基底直径、山顶直径与基底直径之比、山体坡度、山体高度与基底直径比值六个参数多元统计分析,发现可以根据山体高度与基底直径的比值对海山形态类型进行分类:比值小于0.10的为平顶海山(Ⅰ类),大于0.10的为尖顶海山(Ⅱ类),对于等于0.10的海山需参考平坦度和山体坡度,平坦度大和山体坡度缓的为Ⅰ类,反之为Ⅱ类。西太平洋的麦哲伦海山区、马绍尔群岛基本以平顶海山为主,介于中西太平洋之间的威克—马尔库斯海山区和中太平洋海山区、莱恩群岛平顶海山与尖顶海山共同发育。对各种类型海山上钴结壳分布研究发现,无论是在尖顶海山还是在平顶海山,板状结壳均比较发育,但砾状结壳在平顶海山比在尖顶海山的发育。中太平洋尖顶海山的结壳比平顶海山的发育,但由于山顶面积小,钴结壳资源量不大。仅从平顶海山看,在麦哲伦海山区、威克—马尔库斯海山区板状结壳比中太平洋海山区、马绍尔群岛、莱恩群岛的板状结壳发育,前者的板状结壳平均厚度大于3 cm,后者的板状结壳平均厚度小于3 cm,总体上是西太平洋平顶海山钴结壳比中太平洋平顶海山的发育。两种类型海山各方向上的资源分布明显不同,在平顶海山的西部山坡的资源比东部山坡的丰富,尖顶海山的则刚好相反。

含磷、硫、氮配原子的钴羰基簇合衍生物的合成和表征

The reaction of Co 2(CO) 8 with organic hetrocyclic dithiophosphinate,SP(Fc)(S)N(C 6H 5)NC(Me),gave three cobalt carbonyl cluster derivatives,Co 4(CO) 8(μ CO) 2(μ 4 S)[μ 4 P(Fc)]f,Co 4(CO) 10 (μ 3 S)[μ η 2 P(Fc)N(C 6H 5)NC(Me)] and Co 2(CO) 5[μ η 2 P(Fc)N(C 6H 5)NC(Me)].These clusters were characterized by elementary analysis,IR, 1HNMR and MS spectroscopy.During the reaction,the precursor was cleaved in its P=S,P S,P N and C S bonds,respectively,to give the fragments as ligands as listed above that coordinated to Co atoms to form the new cluster molecules.

四核钴羰基簇合物的合成和晶体结构

用 Co2 (CO) 8与有机杂环二硫代次膦酸盐 SP(C6 H4 OR) (S) N(C6 H5) NC(Me) (R=Me,Et)反应 ,得到两类 4个含 S,P桥基配体的四核钴羰基簇合物 Co4 (CO) 1 0 (μ4 -S) [μ4 -P(C6 H4 OR) ](1 :R=Me;3 :R=Et)和 Co4 (CO) 1 0 (μ3-S) [μ2 -P(C6 H4 OR) N(C6 H5) NC(Me) ](2 :R=Me,4:R=Et) .在反应中 ,前配体中的P S键以及 C— S,P—S,P— N键劈开 ,产生的分子片与金属钴原子配位 ,组建成新的羰基钴簇 .对这 4个簇合物进行了元素分析 ,IR,1 H NMR和 MS谱学表征 ,并测定了簇合物 4的晶体结构 ,该晶体属单斜晶系 ,P2 1 /c空间群 ,晶胞参数 a=1 .90 65 (4 ) nm,b=1 .0 0 81 (2 ) nm,c=1 .6663 (3 ) nm,β=97.3 6(3 )°,V=3 .1 70 4(1 1 ) nm3,Z=4,Dc=1 .743 g/cm3.Co1 Co3 Co4呈三角形分布 ,其中 Co— Co平均键长为 0 .2 5 1 nm,而 Co2在该三角平面的一侧 ,Co2—Co3键为 0 .2 69nm.该簇合物分子骨架为三角钉型结构 ,每个 Co原子的立体几何均为变形八面体 。

含环偶磷氮烷取代基的二核钴羰合物的合成和分子结构

用Co2(CO)8与环偶磷氮烷[cis-(tBuNP)2(tBuNH)2]反应得到了一取代产物Co2(CO)7-[cis-(tBuNP)2(tBuNH)2].对其进行了元素分析及IR、1HNMR等谱学表征,并用X-ray衍射技术测定了它的单晶结构.该晶体属三斜晶系,P1-空间群.化学式:C23H38N4O7P2Co2,Mr=662.37.晶胞参数a=15.193(2) ,b=16.350(3) ,c=14.995(2) ,α=108.311(4)°,β=89.969(7)°,γ=64.316(5)°,V=3145.8(8) 3,Z=4,Dc=1.394Mg/m3.

非晶态原子团簇Co_nP_m^+、Ni_nP_m^+的生成与结构分析

应用量子化学从头计算方法研究了激光等离子体反应生成的非晶团簇ＣｏｎＰ＋ｍ、ＮｉｎＰ＋ｍ．考查和分析了可能的几何构型及稳定性．ＣｏｎＰ＋ｍ有两条生长螺线：１）从ｍ＝４到ｍ＝８，构型变化为四边形→三角双锥→畸变八面体→双四面体；２）从ｍ＝７到ｍ＝１１，构型变化为三棱柱加帽→长方体→四棱柱加帽→五棱柱，其中Ｃｏ嵌在多面体中．ＮｉＰ＋ｍ只有一条生长螺线ＮｉＰ＋７～ＮｉＰ＋１１，Ｐｍ形成网络，Ｎｉ仅与其中部分Ｐ原子成键．

酞菁钴/铁纳米填充母粒组成的磁流变液性能

采用有机／无机原位（ｉｎ ｓｉｔｕ）复合方法制备得出酞菁钴／铁纳米填充母粒，与甲基硅油组成磁流变液（ＭＲＳ）。ＭＲＳ的附加动态剪切应力（△τ）与分散介质浓度、外加磁场强度呈正比例关系；剪切速率对△τ的影响表明磁致流变为链状结构特征；△τ对温度不敏感；ＭＲＳ对外加磁场有可逆的开／关变化特征，无记忆效应，磁流变响应时间小于０．１ｓ。

RCCo_3(CO)_9的电化学和RCCo_3(CO)_9^-的ESR谱研究

本文对三种RCCo_3(CO)_9及相应的自由基进行了电化学和ESR谱研究.电化学研究表明,RCCo_3(CO)_9被还原为自由基的难易与R的性质有关,RCCo_3(CO)_9在室温下可以稳定存在.在对分子轨道对称性分析的基础上对簇合物自由基的ESR谱进行了讨论.确定了超精细偶合常数的符号和未成对电子占据轨道的性质,计算了Co的3d轨道和4s轨道的自旋密度.