Anderson型和Waugh型杂多阴离子的电子结构及其催化性…

使用ＳＣＣ－ＤＶ－Ｘａ法研究了两种杂多阴离子－－（ＩＭｏ６Ｏ２４）＾５－（Ａｎｄｅｒｓｏｎ型）和（ＮｉＭｏ９Ｏ３２）＾６－（Ｗａｕｇｈ型）的电子结构，并探讨了它们的催化性能。结果表明，两类杂多阴离子均具有催化活性，但不如Ｋｅｇｇｉｎ结构强，（ＩＭｏ＾Ｏ２４）＾５－的催化活性中心是端氧Ｏｔ和中心八面体氧Ｏｔ（ＮｉＭｏ９Ｏ２４）＾６－的催化活性中心是一配位端氧Ｏｔ、四配位中心氧中心杂原子Ｎｉ，两类杂多     

Dawson结构硫钼杂多阴离子的电子结构

使用第一原理密度泛函理论中的离散变分方法（DFT-DVM）对（S2Mo18O62）4-的电子结构进行了理论计算,并与Keggin结构（SMo12O40）2-的电子结构作了比较分析,结果表明,（S2Mo18O62）中的电子离域地分布在整个阴离子骨架中,但极位和赤道位原子的电荷分布有明显差异。端氧与Mo之间的键均较强,中心氧与Mo之间形成的键最弱。（S2Mo18O62）4-的化学行为的活性中心是赤道位钼Moe、极位端氧Opt、极位共顶桥氧Opea、赤道位端氧Oet和赤道位共边桥氧Oeb。与（SMo12O40）2-相比,（S2Mo18O62）4-的稳定性和氧化性均较弱。但在两种类型的硫钼杂多阴离子中,Mo对其氧化性的产生起了重要的作用。     

[SiMo_2~(Ⅴ)Mo_(10)~(Ⅵ)O_(40)]~(6-)及其钒取代物的量子化学研究

采用SCC－DV－Xα方法对α－Keggin结构硅钼二电子还原态杂多蓝阴离子［SiMo2（V）Mo10（VI）O40］6-和它的混合型钒取代物［SiV2（V）Mo10（VI）O40］6-进行了量子化学计算，获得了轨道能级、费米能级、各原子价电子布居、自由价态密度分析和分子轨道成分等信息．理论分析表明该杂多阴离子中所有原子Si、Mo、V、Oa、Ob、Oc和Od都参与反应，Oc和Od的成键能力较强，化学活性较大，有力地支持了实验结果．中心硅氧四面体结构发生畸变很小，但构成三金属簇的八面体结构都发生了较明显的畸变，其整体仍然保持α－Keggin结构．钒的取代增强了Mo2VO13三金属族中Od的活性．预测这两种杂多阴离子都有被继续还原和取代的趋势，[SiMo2(V)Mo10(VI)O40]6-的趋势更强．     

Ni-V-O催化剂的合成、表征及其催化性能

制备了Ni3V2O8, Ni2V2O7, NiV2O6催化剂, 进行了XRD, BET, H2-TPR, XPS和电导等表征, 并测试了这三种结构催化剂对丙烷氧化脱氢制丙烯反应的催化性能, 分析了影响催化性能的因素. 实验结果表明, 当丙烷的转化率为10%时, 在p-型半导体Ni3V2O8和Ni2V2O7催化剂上丙烯的选择性为69.13%和70.21%, 而在n-型半导体NiV2O6上, 丙烯的选择性为64.41%, 表明p-型半导体Ni3V2O8和Ni2V2O7的催化性能优于n-型半导体NiV2O6的催化性能. XPS实验结果表明, 这可能与p-型半导体正钒酸镍(Ni3V2O8)和焦钒酸镍(Ni2V2O7)催化剂表面含较多O-氧物种和V4+有关.     

乙烷部分氧化超细Fe－Mo－O催化剂的研究

采用溶胶-凝胶法制备了Fe－Mo－O催化剂，用XRD、TEM、BET、IR、TPR、TPD和微反等技术研究了催化剂晶体结构、表面构造、晶格氧活泼性、化学吸附和乙烷部分氧化反应性能。Fe－Mo－O复合氧化物催化剂是由超细微粒组成，微粒粒径约10 nm～20 nm，比表面积为48.1 m2/g。催化剂表面由Lewis碱位（Mo=O键的端氧和Fe－O－Mo键中的桥氧）及Lewis酸位构成。乙烷能以甲基中的H原子吸附在催化剂表面Lewis碱位Mo=O的端氧上形成分子吸附态，其部分氧化产物主要是C2H4和少量的CH3CHO。     

PEO／V2O5复合薄膜中Li^＋的位置与电子结构研究

采用自洽场离散变分Xα（SCC-DV-Xα）方法对纯V2O5及夹层V2O5的能带结构、态密度、键强度、电子集居数等进行了研究，结果表明，Li^ 引入V2O5层间的最佳位置在在双键氧之下（或之上），且靠近层的中心位置，此时它与周围原子间的作用力非常微弱，并且材料的导电性增强，使夹层复合材料Li^ 注入／脱出具有很好的可逆性和较好的光学性质。     

铕缔合物(C34H54N2O10)［Eu(NO3)5］的合成和晶体结构

在乙腈溶液中合成了标题化合物,（C(34)H(54)N2O10）[Eu（NO3）5]（C(34)H(52)H2O(10)＝1,2-二（2,3-苯并-10－氮杂-15-冠-5－N-乙氧基）乙烷）并用X射线衍射分析测定了它的结构。该晶体属单斜晶系,P21／c空间群,晶胞参数：a＝1．1801（2）nm,b＝2．3560（5）nm,c＝1．7025（3）nm,β=99．67（3）°。V＝4．6662（16）nm',Z＝4,Dc=1．581g·cm(－3)。Eu(3 )与5个NO3的10个O配位。大环化合物上无论是O还是N都未与Eu(3 )成键。     

三苯基锡与邻氨基苯甲酸型Schif碱配合物的合成及表征

合成了两种新的三苯基锡与邻氨基苯甲酸型Ｓｃｈｉｆ碱的配合物，经元素分析、ＵＶ、ＩＲ、１ＨＮＭＲ测定，对其结构进行了表征。结果表明，两种配合物具有不同的结构。在三苯基锡与水杨醛缩邻氨基苯甲酸Ｓｃｈｉｆ碱的配合物中，锡原子是六配位的，存在着酚羟基氧和亚氨基氮与锡的配键。在三苯基锡与２－羟基－１－萘醛缩邻氨基苯甲酸Ｓｃｈｉｆ碱的配合物中，锡原子是五配位的，酚羟基氧和亚氨基氮均未与锡配位，但存在着羰基氧与锡的配键     

[Zn2（C7H8O6）2（bipy）2（H2O）2]·4H2O手性配位聚合物的合成与晶体结构

采用溶剂热技术合成了一种新型手性配位聚合物[Zn2（C7H8O6）2（bipy）2（H2O）2]·4H2O（C7H8O6=2,3-氧-异丙叉基-L-酒石酸根,bipy=4,4′-联吡啶）,并通过单晶X射线衍射结构分析、元素分析、热重分析以及红外光谱进行了表征.结构分析数据表明,该化合物属单斜晶系,C2空间群,晶胞参数a=2.02334（14）nm,b=1.13896（4）nm,c=1.01094（6）nm,β=117.366（3）°,V=2.0689（2）nm^3.两个晶体学独立的Zn原子均为八面体构型,其中Zn1原子赤道配位点被2个酒石酸根中的4个羧酸根氧螯合配位,2个酒石酸根中剩下的4个羧酸根氧中的2个分别与2个Zn2原子连接形成无限一维链,Zn2原子的另外2个反式赤道配位点被2个水分子氧占据,同时这两种Zn原子的轴向配位点均被4,4′-联吡啶的氮原子占据,形成具有矩形格子[0.51165（3）nm×1.13896（5）nm]的二维层状结构,游离的2个水分子通过氢键作用形成二聚体,并与酒石酸根中未与Zn配位的羧酸氧连接,把二维层状结构连接成三维网状的超分子结构.     

取代基对咔咯锰(V)-氧配合物Mn―O的成键影响

用密度泛函理论(DFT)方法对一系列A₃型咔咯锰(V)氧配合物进行了理论计算. 结果表明: 咔咯锰(V)-氧配合物中Mn―O键是由1 个σ键和2 个π键构成的叁键结构; 当咔咯中位取代基由推电子过渡到拉电子性质时, 咔咯骨架紧缩, Mn―O键缩短, 其拉曼光谱的伸缩振动峰往高波数移动; 取代基与氧原子的静电作用模式由正-负吸引转化为负-负排斥, 导致Mn―O键解离能ΔE减少, 即拉电子基团有利于增强咔咯锰(V)-氧配合物氧原子的活泼性.     

Density functional theory study of small vanadium oxide clusters

Density functional theory is employed to study structure and stability of small neutral vanadium oxide clusters in the gas phase. BPW91/LANL2DZ level of theory is used to obtain structures of VOy (y=1-5), V2Oy (y=2-7), V3Oy (y=4-9), and V4Oy (y=7-12) clusters. Enthalpies of growth and fragmentation reactions of the lowest energy isomers of vanadium oxide molecules are also obtained to study the stability of neutral vanadium oxide species under oxygen saturated gas-phase conditions. Our results suggest that cyclic and cage-like structures are preferred for the lowest energy isomers of neutral vanadium oxide clusters, and oxygen-oxygen bonds are present for oxygen-rich clusters. Clusters with an odd number of vanadium atoms tend to have low spin ground states, while clusters with even number of vanadium atoms have a variety of spin multiplicities for their ground electronic state. VO2, V2O5, V3O7, and V4O10 are predicted to be the most stable neutral clusters under the oxygen saturated conditions. These results are in agreement with and complement previous gas-phase experimental studies of neutral vanadium oxide clusters.     

二维层状铈配合物｛[Ce(aip)(Haip)(H_2O)_2]·H_2O｝n的水热合成及其晶体结构

在水热条件下,以Ce(NO3)3.6H2O和5-氨基间苯二甲酸为原料,合成了一种具有二维层状结构的铈配合物{[Ce(aip)(Haip)(H2O)2].H2O}n(H2aip=5-aminoisophthalic acid).利用红外光谱和X射线单晶衍射分析表征了其结构.结果表明,标题配合物属于三斜晶系,P-1空间群,晶胞参数为:a=0.697 70(8)nm,b=1.928 8(13)nm,c=1.196 26(14)nm,α=90.209(2)°,β=97.388(2)°,γ=93.246(2)°,V=0.903 07(18)nm3,Z=2,Dc=2.032mg/m3,F(000)=544,R1=0.024 5,wR2=0.062 2.在该配合物中,中心金属离子Ce(Ⅲ)与氧相连形成九配位构型,并通过π…π堆积和氢键形成三维扩展结构.     

基于氨三乙酸和钕的三维金属有机框架物的合成及结构表征(英文)

利用水热法合成了三维网状金属有机框架物[Nd(NTA)(H2O)]∞[其中NTA指氨三乙酸根(nitrilotriacetate anion)];采用元素分析仪、红外光谱仪和X射线单晶衍射仪等分析了产物的组成以及化学结构和晶体结构。结果表明,目标配合物中的NTA为四齿配体,Nd(III)原子采取八配位模式(NdN1O7)形成十二面体立体结构。与此同时,[Nd(NTA)(H2O)]∞以菱形四面体Nd8C14O28为构筑块,通过桥连羧基和分子间氢键组装成为三维超分子网络结构。     

二正丙基胂酸合六聚钼酸四胍盐(CN3H6)4[(n-C3H7As)2Mo6O24]的晶体和分子结构

一种新型有机胂合聚钼酸盐(CN_3H_6)_4[(n-C_3H_7As)_2Mo_6O_(24)]的晶体属于正交晶系, 空间群为Cmca, 晶胞参数为: a=1.3938(1), b=1.6350(2), c=1.6173(2) nm直接法得出所有钼、砷原子的位置, 再由差值Fourier合成得到全部其他非氢原子位置。采用全矩阵最小二乘法精修, 最后的R因子为0.047。在该结构中, 阴离子呈笼状结构并具有较高的C_(2h)的对称性。键长数值在正常的范围内, 配位氧与钼原子的键角呈有规律的变化。氢键联结阴、阳离子并纵横于整个空间的各个方向, 形成网状分布, 对晶体的稳定起着重要的作用。     

二聚体有机锡配合物{[n-Bu2Sn(O2CCH2CS2NC4H8)]2O}2的合成，表征及晶体结构(英)

The title compound, {[n-Bu₂Sn(O₂CCH₂CS₂NC₄H₈)]₂O}₂, has been synthesized by the reaction of (tetrahydro-pyrrodithiolocarbamoylthio)acetic acid with the di-n-bubyltin oxide in 1∶1 molar ratio. The complex has been characterized by elemental analysis, IR and NMR. The crystal structure of it has been determined by X-ray single crystal diffraction. And the results showed that the crystal belongs to triclinic system with space group P1 and some crystal parameters: a=1.220 2(9) nm, b=1.315 8(10) nm, c=1.380 4(10) nm, α=111.215(9)°， β=99.357(9)°， γ=96.075(10)°, V=2.006(2) nm³, Z=1, F(000)=908, μ=1.489 mm^-1, D_c=1.474 g·cm^-3, R₁=0.037 5, wR₂=0.0839. The complex has a centrosymmetric dimer structure mode with a four-membered central endo-cyclic Sn₂O₂ unit in which two bridged oxygen atoms both connect with an exo-cyclic tin atom which has a distorted octahedron. Each of the endo-cyclic tin atoms exhibits a distorted trigonal bipyramid coordination geometry with an additional weak coordination carboxylate oxygen. Four carboxylate ligands are divided into two types. And two of them are bidentate and connecting to each of exo-cyclic tin atoms by using both oxygen atoms, whereas the others bridge to each pair of exo-and endo-cyclic tin atoms utilizing one oxygen atom only. CCDC: 220513.     

Near-edge X-ray absorption fine structure study of disordering in Gd2(Ti1-yZry)2O7 pyrochlores

Disorder in Gd2(Ti(1-y)Zry)2O7 pyrochlores, for y = 0.0-1.0, is investigated by Ti 2p and O 1s near-edge X-ray absorption fine structure spectroscopy. Ti(4+) ions are found to occupy octahedral sites in Gd2Ti2O7 with a tetragonal distortion induced by vacant oxygen sites. As Zr substitutes for Ti, the tetragonal distortion decreases, and Zr coordination increases from 6 to 8. The migration of oxygen ions from 48f or 8b sites to vacant 8a sites compensate for the increased Zr coordination, thereby reducing the number of vacant 8a sites, which further reduces the tetragonal distortion and introduces more disorder around Ti. This is evidence for simultaneous cation disorder with anion migration.     

由Keggin型簇和过渡金属配合物构筑的杂多钨酸盐锯齿链的合成和结构

采用水热法合成了一维锯齿链状的有机-无机杂化杂多钨酸盐[Cu（en）2（H2O）]{[Cu（en）2（H2O）][Cu（en）2]（α-SiW12O40）}（OH）2·H2O（记作1;en=1,2-乙二胺）;利用元素分析、红外光谱和X射线单晶衍射对其结构进行了表征.结果表明,化合物1属于三斜晶系,P-1空间群;其晶格参数为：a=1.297 6（6）nm,b=1.473 5（7）nm,c=1.909 9（9）nm,α=86.736（8）°,β=88.833（8）°,γ=74.840（8）°,V=3.519（3）nm3,Z=2.就分子结构而言,化合物1由一个常见的Keggin型多阴离子[α-SiW12O40]4-、两个不同的铜配位阳离子[Cu（en）2（H2O）]2＋和[Cu（en）2]2＋、一个游离的铜配位阳离子[Cu（en）2（H2O）]2＋、两个氢氧根离子和一个结晶水组成;相邻的[α-SiW12O40]4-多阴离子通过两个配位阳离子[Cu（en）2）]2＋相连,形成一维锯齿链状结构.     

Elucidation of the molecular structure of hydrated vanadium oxide species by X-ray absorption spectroscopy: correlation between the V...V coordination number and distance and the point of zero charge of the support oxide

The effect of the point of zero charge (PZC) of the support oxide (Al(2)O(3), Nb(2)O(5), SiO(2) and ZrO(2)) on the molecular structure of hydrated vanadium oxide species has been investigated with EXAFS spectroscopy for low-loaded vanadium oxide catalysts. It was found that the degree of clustering (i.e., the V[dot dot dot]V coordination number) and the V...V distance increase with decreasing PZC of the support oxide; i.e., Al(2)O(3) (8.7) < ZrO(2) (7) < Nb(2)O(5) (3.3) < SiO(2) (2). Upon hydration the silica-supported vanadium oxide exhibited a clear alteration in the position of the oxygen atoms surrounding the central vanadium atom and the number of oxygen atoms around vanadium increased to five. In contrast, only minor changes in the molecular structure were detected for the alumina-, niobia- and zirconia-supported vanadium oxide catalysts. Based on a detailed analysis of the EXAFS data a semi-quantitative distribution of vanadium oxide species present on the surface of the different support oxides can be obtained, which is in good agreement with earlier characterization studies primarily making use of Raman spectroscopy.     

X-ray crystal structure of azoxybenzene oxotetrachlorotungsten(VI), (C6H5N)2OWVIOCl4

The crystal and molecular structure of azoxybenzene oxotetrachlorotungsten(VI) has been determined from X-ray diffractometer data. The structure was solved by Patterson and Fourier methods and refined by least-squares techniques to R = 0.058 for 1869 independent reflections.The crystals are monoclinic, space group P2₁/c, with Z = 4, in a unit cell of dimensions: a = 8.314(3), b = 15.100(5), c = 12.901(7) Å, α = 95.31(5)°. The azoxybenzene residue, the structure of which resembles that of free trans azobenzene, is linked to the tungsten atom through its oxygen atom. The coordination at the metal (two oxygen atoms and four chlorine atoms) corresponds to a distorted octahedron.This distortion is very similar to those observed in similar tungsten compounds. There is a intramolecular C?O distance of 2.77 Å between two atoms four bonds apart, of the azoxybenzene residue.