(enH2)5[(VO)12O6B18O36(OH)6]·2(H3O)·6H2O的水热合成和晶体结构

以NH4VO3,H3BO3,乙二胺,MoO3,H2O为原料,按物质的量比2∶20∶9∶3∶222,在180℃条件下晶化,得到黑色棱形晶体(enH2)5[(VO)12O6B18O36(OH)6].2(H3O).6H2O.单晶结构分析结果表明该化合物属三斜晶系,Pī空间群,晶胞参数a=1.336 8(3)nm,b=1.599 8(3)nm,c=1.663 4(3)nm,α=94.040(1)°,β=91.530(1)°,γ=95.830(1)°,V=3.528 1(12)nm3,Z=2,Dc=2.099 g/cm3,μ=1.649 mm-1,F(000)=2 228,15 641个可观察独立衍射点射点(I>2σ(I)),最后结构精修到偏离因子R1=0.047 5,wR2=0.150 4,S=1.039.该化合物的结构主要由阴离子簇[(VO)12O6B18O36(OH)6]12-构成.该阴离子簇由B18O36(OH)6十八元环夹在两个以共边交替相连形成的V6O18簇中间,通过共用氧原子形成三明治式结构新颖的硼-钒-氧离子簇,簇间填充了一些(enH2)2+离子和水分子.     

Co(III)离子在二氧化铅电极上的阳极形成

文献上曾报导过Co(Ⅱ)离子具有加速PbO_2电极上氧阳极析出过程的作用,并表明当Co(Ⅱ)离子存在时,氧的析出过程有可能通过表面吸附的高价钴氧化物氧化水分子而形成.本文通过浓硫酸溶液中Co(Ⅱ)阳极氧化为Co(Ⅲ)以及O_2阳极析出动力学的研究,表明了O_2的析出和Co(Ⅲ)的形成是通过吸附在电极表面的高价钴(Ⅳ)的OH 基配合物分别氧化水分子和Co(Ⅱ)离子形成的,它与Cr(Ⅲ)、Mn(Ⅱ)离子的阳极氧化过程相类似,而不是通过Co(Ⅱ)离子直接放电形成的.本文利用文献所述的研究方法.在固定硫酸浓度(3.4mol·kg~(-1))下,研究CoSO_4浓度(0.05—0.35mol·drn~(-3))对于O_2和Co(Ⅲ)阳极形成过程分别的影响.在固定CoSO_4(0.2mol·     

Combination of Lindqvist-type Tungstovanadates and Transition Metal Clusters under Hydrothermal Conditions

<正>Two novel organic-inorganic heteropolyoxometalate compounds [{Cu(1,10- phen)OH}_2]_2[V_2W_4O_19]·6H_2O (1) and [Co(1,10-phen)_3]_2[V_2W_4O_(19)]·5H_2O (2) (1,10-phen = 1,10- phenanthroline) were hydrothermally synthesized and characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. Compound 1 contains a di-V substituted classical Lindqvist-type polyanion [V_2W_4O_(19)]~(4-), two dinuclear copper cations [{Cu(1,10-phen)OH}_2]~(2+) and six water molecules of crystallization. Two dinuclear copper cations [{Cu(1,10-phen)OH}_2]~(2+) consist of four transition metal coordination cations {Cu(1,10-phen)}~(2+), bridged by four hydroxyl groups. Meanwhile, both two dinuclear cations are grafted on the Lindqvist polyanion [V_2W_4O_(19)]~(4-) through two terminal oxygen (O(9)) and two μ_2-oxygen (O(6)) atoms. Such an unusual linking fashion is unique in the polyoxometalate chemistry. The basic framework of 2 is similar to that of 1 and contains one Lindqvist-type polyanion [V_2W_4O_(19)]~(4-), two six-coordinated cobalt cations [Co(1,10-phen)_3]~(2+) and five free water molecules.     

单斜Li3V2(PO4)3/C复合材料的制备及其电化学性能

以LiOH·H2O、V2O5、H3PO4和蔗糖为原料,采用软化学法制备了锂离子电池正极材料Li3V2(PO4)3/C.通过X射线衍射(XRD)、扫描电镜(SEM)对产物的结构和形貌进行表征,采用恒电流充放电、电化学阻抗考察了产物的电化学性能.结果表明.当煅烧温度达到700℃时,杂质相衍射峰消失,所得的样品为纯相的单斜Li3V2(PO4)3.颗粒粒度为1～2 μm;在3.0～4.5 V电压范围内以0.2C倍率充放电,首次放电比容量达到148.2 mAh·g-1,第50次循环比容量仍为144 mAh·g-1,容量保持率为97%,具有良好的循环性能;另外,样品还具有很好的倍率性能和高温性能.     

A Layered Vanadium Oxide with Cobalt（Ⅱ） Coordination Complex： Hydrothermal Synthesis and Crystal Structure of （py）5Co2（H2O）3[V4O12]

A novel layered mixed metal vanadium-cobadt complex, （py）5Co2（H2O）3[V4O12] 1 （py = pyridine）, was hydro（solvo）thermally synthesized and characterized by single-crystal X-ray diffraction. It crystallizes in orthorhombic, space group Pca21 with a = 17.473（4）, b = 11.447（2）, c = 17.509（4）A^°, V = 5005.3（7）A^°3, Z = 4, Mr = 3502.1（12）, Z = 4, Dc = 1.827 g/cm^3,μ（MoKα） = 2.023 mm^-1, F（000） = 1928, S = 1.020, the final R = 0.0400 and wR= 0.1063 for 6035 observed reflections with I 〉 2σ（I） and 460 variables. Complex 1 consists of tetrahedral VO4 groups to form the large layers which are alternately bonded by two cobalt complex species Co（py）2（H2O）2 and Co（py）3（H2O）.     

A Density Functional Theory Study of the Hydrates of 2NH_3:H_2SO_4 and Its Implications for the Formation of Atmosphere Particles

Density functional theory was used at the B3LYP/6-311++G(d,p) level of theory to study the hydrates of 2NH3:H2SO4:nH2O for n = 0～4. Neutrals of the most stable clusters, when n = 0 and 1, spontaneously formed and were determined to be hydrogen-bonded molecular complexes of monomeric species. Double ions (clusters containing a NH4+ cation and a HSO4- anion) or even ternary ions (clusters with two NH4+ cations and one SO42- anion) spontaneously formed in the most stable clusters of 2NH3:H2SO4:nH2O (n = 2, 3, 4). The energetics of binding and incremental association was also calculated. Double ions are not energetically favorable until 2NH3:H2SO4:2H2O because of the about equal free energies for forming the neutral (the most stable) and double ion (the second stable) isomers. The free energy of incremental association from free H2O and 2NH3:H2SO4:nH2O has a maximum at n = 2 at room temperature with ΔG ≈ -2 kcal/mol. The comparison of incremental association energies between 2NH3:H2SO4:nH2O, NH3:H2SO4:nH2O and H2SO4:nH2O clusters revealed that NH3 plays an important role in the atmospheric particle nucleation.     

Copper Carboxylate-phosphonates: Syntheses,Crystal Structures and Magnetic Properties

Two novel copper carboxyly-phosphonates, namely, Cu_(2.5)(5-pnc)(SO_4)_(0.5)(OH)(H_2O)_(0.5)(1) and Cu_(0.5)(5-pncH_2)(H_2O)_(1.5)(2)(5-pncH_3 = 5-phosphono-1-naphthalenecarboxylic acid), have been synthesized and characterized by X-ray diffraction, infrared spectroscopy, elemental analysis, and thermogravimetric analysis. In compound 1, each {PO_3C} tetrahedron is corner-shared with two {Cu(1)O_4}, two {Cu(2)O_5} and one {Cu(3)O_5},thus forming a one-dimensional inorganic chain along the c axis containing 8-membered rings of [Cu_3O_4S] and 19-membered cages of [Cu_5O_(10)P_4]. The inorganic chains are further connected by a 5-pnc~(3-) ligand to generate a three-dimensional framework. Compound 2 exhibits a one-dimensional structure, in which the inorganic chains of [Cu-O-Cu]_n are connected by the organic ligands through hydrogen bonding interactions, forming an infinite two-dimensional layer. Magnetic measurements of 1 indicate that dominant antiferromagnetic interactions are mediated between the Cu~(2+) centers.     

水溶性双甲基化大豆苷元磺酸钴的合成及其晶体结构

以大豆苷元为先导化合物,合成了水溶性异黄酮衍生物--4′,7-二甲氧基异黄酮磺酸钴{[Co(H_2O)_6](C_(17)H_(13)O_4SO_3)_2·8H_2O(1)},其结构经~1H NMR,IR,元素分析和X-射线单晶衍射表征.1属单斜晶系,空间群P21/c,晶胞参数a=18.697(4)(A),b=7.358(2)(A),c=18.368(4)(A),β=116.223(1)°,Z=2.1的Co(Ⅱ)位于对称中心并被6分子水所配位;[Co(H_2O)_6]~(2+),[C_(17)H_(13)O_4SO_3]~- 和H_2O之间存在多种氢键,形成晶体结构中的亲水区.异黄酮骨架间反平行排列,存在着π┈π堆积作用,构成晶体结构中的疏水区.磺酸根是连接亲水区和疏水区的桥梁.氢键、π┈π堆积以及阴阳离子之间的静电引力作用共同将1组装成具有三维网络结构的超分子.     

CdS纳米棒/酞菁氧钛复合光导体的光电导性能

采用以溶剂热方法合成的CdS纳米棒与酞菁氧钛复合制备的复合光导体,在570nm光照下其光电导性能明显提高,将质量分数为5%的CdS纳米棒与TiOPc复合使光敏性能提高32%.电子结构的数据和表面光电压谱分析结果表明,复合体系中存在从CdS纳米棒到TiOPc的光致空穴转移,TiOPc因被CdS纳米棒敏化而表现出高的光电导性能.     

硫物种对负载型钯催化剂上氢吸附性质的影响

用X光光电子能谱(XPS)分析了负载型Pd/Al_2O_3催化剂上硫和钯的状态。以程序升温脱附-质谱(TPD-MS)方法研究了不同硫物种及不同气氛对催化剂氢吸附性质的影响。结果表明: 硫物种对氢吸附的影响按S_2~(2-)、S~(2-)、SO_4~(2-)的顺序减小, 且前两者的影响远比SO_4~(2-)的大。这与催化剂在H_2-O_2反应中的抗硫性评价结果一致。并用原子分子轨道理论对上述结果进行了讨论。     

V2O5在硅胶表面的分散及助剂K2SO4作用的研究

用原位XRD方法证明V_2O_5能在硅胶表面自发分散, 但所需温度较高. 水汽对V_2O_5的分散有一定的阻碍作用. K_2SO_4可显著加快V_2O_5在SiO_2表面的分散速度, 并能降低V_2O_5/SiO_2的表面酸性. 被中和的主要是强酸位. 这可能是K_2SO_4能够改善V_2O_5/SiO_2催化剂在选择氧化反应中选择性的重要原因之一.     

气相中Fe~(2+)和H_2O_2作用生成OH自由基的理论研究

利用B3LYP方法，在6-311G基组下研究了气相中Fe~(2+)与H_2O_2作用生成OH自 由基的反应途径，探讨了铁离子对生成羟基自由基所起的作用。结果表明反应的途 径为：Fe~(2+)与H_2O_2首先形成中间体（FeO_2H_2）~(2+)，然后能过O-O键的断 裂生成中间体（HOFeOH）~(2+)，再断Fe-OH键生成羟基自由基，Fe~(2+)和H_2O_2 的电荷强烈相互作用以及Fe~(2+)的d轨道上的电子促进H_2O_2中的O-O键断裂，生 成羟基自由基。     

五元体系Li~+,K~+//CO_3~(2-),SO_4~(2-),B_4O_7~(2-) -H_2O在288 K时的介稳相平衡研究

采用等温蒸发法研究了五元体系Li~+,K~+//CO_3~(2-),SO_4~(2-),B_4O_7~(2-) -H_2O在288 K时的介稳相平衡关系,测定了该五元体系在288 K条件下的介稳平衡的溶解度和溶液密度,根据实验数据绘制了相应的介稳平衡相图和水图,相平衡研究结果表明该五元体系介稳相平衡中有复盐K_2SO_4·Li_2SO_4生成,其介稳相图(Li_2CO_3饱和)有4个共饱和点,9条单变量曲线,6个Li_2CO_3饱和的结晶区分别为LiBO_2·8H_2O,K_28_4O_7·4H_2O,K_2CO_3·3/2H_2O,K_2SO_4,Li_2SO_4·H_2O和复盐K_2SO_4·Li_2SO_4.     

固体超强酸SO_4~(2-)/TiO_2对酯化反应的催化作用

1979年Hino等首先合成了SO_4~(2-)/TiO_2,SO_4~(2-)/ZrO_2等新型固体超强酸,它们有特殊的催化性能,且具有不怕水,可在高温下使用、制备方便、减少三废等优点,因此有广泛的应用前景,引起国内外催化工作者的兴趣和重视. 我们仿照Hino法合成了SO_4~(2-)/TiO_2体超强酸催化剂,测定了酸强度和比表面.本研究着眼点是取代有严重腐蚀作用的浓H_2SO_4催化剂,选用两类酯化反应考察了SO_4~(2-)/TiO_2的催     

两类稀土钒酸盐的合成与结构

通过（１）ＬｎＯＣｌ／Ｖ＿２Ｏ＿５，（２）ＬｎＣｌ３／Ｖ及（３）ＬｎＯＣｌ／ＬｎＣｌ／Ｖ＿２Ｏ＿５／Ｖ的高温固态化学反应，得到两种稀土钒酸盐：Ｌｎ＿６Ｖ＿３Ｃｌ＿（１０）Ｏ＿（１２）（Ｌｎ＝Ｌａ）及Ｌｎ＿４Ｖ＿５Ｓｉ＿４Ｏ＿（２２）（Ｌｎ＝Ｌａ～Ｎｄ）。Ｌａ＿６Ｖ＿３Ｏ＿（１０）Ｏ＿（１２）晶体呈浅色透明片状，其结构可认为是由［Ｌａ＿３（ＶＯ＿４）＿３Ｃｌ］单元插入到ＬａＣｌ３结构单元中而形成的，在结构中沿ｃ轴方向存在一系列截面积为１９．１的空洞。Ｌｎ＿４Ｖ＿５Ｓｉ＿４Ｏ＿（２２）（Ｌｎ＝Ｌａ，Ｃｅ，Ｐｒ，Ｎｄ）晶体呈，黑色针状，其结构可认为是由交替的稀土钒硅酸盐薄层及钒氧金红石层沿ｃ轴堆叠而表现为准二维Ｃｈｅｖｋｉｎｉｔｅ型结构。     

羟基磷灰石中氢键的XPS考察

Several calcium orthophosphates (tricalcium phosphate, monocalcium dihydropho-sphate, dicalcium hydrophosphate, and hydroxyapatite) are characterized by XPS and IR method. The P2p electron binding energies follow the order Ca(H_2PO_4)_2>CaHPO_4>Ca_(10)(OH)_2(PO_4)_6>Ca_3(PO_4)_2. It is expounded that there is hydrogen bonding of (OH...OPO_3) between the OH~- ion and the neighbour oxygen of the phosphate in hydroxyapatite.     

没食子酸丙酯Fe(Ⅲ)、Cr(Ⅲ)、Cu(Ⅱ)配合物的合成、表征及模拟超氧化物歧化酶

研究了没食子酸丙酯在水溶液中分别与Fe3+、Cr3+、Cu2+生成没食子酸丙酯-铁(PG-Fe)、没食子酸丙酯-铬(PG-Cr)、没食子酸丙酯-铜(PG-Cu)这3种金属配合物(PG-M)的反应。 通过紫外光谱、核磁共振、红外光谱、质谱、元素分析、摩尔电导率和循环伏安法等测试技术对3种金属配合物进行了表征。 确定3种金属配合物的分子式分别为[C10H10O5]2Fe·H2O、[C10H10O5]3Cr·2H2O、[C10H10O5]2Cu·2H2O。 红外光谱分析表明,中心金属原子与酚羟基发生配位,形成Ar-O-M键。 电化学数据显示,PG-M的抗氧化性优于PG配体,且PG-Cu＞PG-Cr＞PG-Fe。 用改进的核黄素光还原NBT法检测了3种金属配合物的模拟超氧化物歧化酶(SOD)活性。 结果表明,3种金属配合物均有一定的催化歧化超氧阴离子自由基(O-2·)活性,均可被称作超氧化物歧化酶活性中心的模拟配合物。     

The catalytic effect of bismuth for VO_2~+/VO~(2+) and V~(3+)/V~(2+) redox couples in vanadium flow batteries

The effect of bismuth(Bi) for both VO_2~+/VO2+ and V~(3+)/V~(2+) redox couples in vanadium flow batteries(VFBs) has been investigated by directly introducing Bi on the surface of carbon felt(CF).The results show that Bi has no catalytic effect for VO_2~+/VO2+ redox couple.During the first charge process,Bi is oxidized to Bi~(3+)(never return back to Bi metal in the subsequent cycles) due to the low standard redox potential of 0.308 V(vs.SHE) for Bi3+/Bi redox couple compared with VO_2+/VO2+ redox couple and Bi~(3+)exhibit no(or neglectable) electro-catalytic activity.Additionally,the relationship between Bi loading and electrochemical activity for V~(3+)/V~(2+) redox couple was studied in detail.2 wt%Bi-modified carbon felt(2%-BiCF) exhibits the highest electrochemical activity.Using it as negative electrode,a high energy efficiency(EE) of 79.0%can be achieved at a high current density of 160mA/cm~2,which is 5.5%higher than the pristine one.Moreover,the electrolyte utilization ratio is also increased by more than 30%.Even the cell operated at 140mA/cm2 for over 300 cycles,the EE can reach 80.9%without obvious fluctuation and attenuation,suggesting excellent catalytic activity and electrochemical stability in VFBs.     

原位漫反射红外光谱法研究SO2对Ag/Al2O3选择性催化丙烯还原NOx反应的影响

 以Ag/Al2O3为催化剂,采用原位漫反射傅里叶变换红外光谱法研究了SO2对C3H6选择性还原NOx反应的影响. 结果表明, SO2在催化剂表面转化为硫酸盐,并且随着硫酸盐累积量的增加,其主要红外特征吸收峰由低波数向高波数漂移. 高浓度表面硫酸盐的存在不仅抑制了催化剂表面硝酸盐的生成,而且抑制了硝酸盐与表面烯醇式物种(RCH=CH-O-)或乙酸盐物种进一步反应,生成活泼的反应中间体异氰酸酯(-NCO), 这是导致Ag/Al2O3催化剂上C3H6选择性还原NOx活性降低的主要原因.