D2EHPA和D2EHDTPA萃取银的研究

本文研究了D₂EHPA和D₂EHDTPA在硝酸体系中萃取和反萃取银的条件,并用饱和法和连续变量法测定了革合物的组成,以红外光谱和核磁共振谱探讨革合物的成键情况,通过EHMO计算结果说明了上述两种革取剂对Ag⁺萃取能力异同的原因。     

A self-catenated network containing unprecedented 0D + 2D → 2D polycatenation array

Herein, we report a new acylamide ligand and its application in the construction of a metal-organic framework. The resultant acylamide metal-organic framework, namely [Zn(2)(L)(OH)(btc)](n) (1, L = N(1),N(4)-bis(pyridin-3-ylmethyl) naphthalene-1,4-dicarboxamide, H(3)btc = benzene-1,3,5-tricarboxylic acid), was obtained by hydrothermal synthesis. The outstanding structural feature of it is the 0D + 2D → 2D polycatenation array containing a self-catenated feature which has never previously been observed. To the best of our knowledge, the coexistence of self-catenation and polycatenation phenomena is highly exceptional.     

D2EHDTPA和D2EHPA萃取汞(Ⅱ)的研究

等曾研究二(2-乙基已基)二硫代磷酸(D2EHDTPA)对多种金属离子的萃取。国内也有人研究它对一些金属离子的萃取。但该萃取剂在硝酸体系中萃取汞(Ⅱ)的研究未见报道。D2EHDTPA与D2EHPA[二(2-乙基己基)磷酸]比较,由于它们形成萃合物时键合原子不同(S-M和O-M),对相同金属离子的萃取能力相差甚大。本文在萃取实验基础上,以量子化学计算结果和有关光谱数据为理论解释了这种现象。     

Novel Hydrogen-bonded Three-dimensional Supramolecular Architectures Containing 2D Honeycomb Networks or 2D Grids

Two new supramolecular complexes,[Cu(H_2dhbd)(3-pyOH)(H_2O)]_2·3-pyOH·2H_2O(1)and[Cu_2(dhbd)(dpa)_2-(H_2O)]·6H_2O(2)(H_4dhbd=2,3-dihydroxybutanedioic acid,3-pyOH=3-hydroxypyddine,dpa=2,2'-dipyridylamine),have been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction,elemental analyses,UV-Vis and IR spectra,and TGA analysis.X-ray structural analysis revealed that,through four pairs of strong O…H—O hydrogen bonds,the cyclic dinuclear units in 1 together with four adjacent neighbors are connected into a 2Dhoneycomb network encapsulating free 3-pyOH ligands.Unexpectedly,the water-dimers are fixed in interlayers of2D honeycomb network and act as hydrogen-bond bridging to further extend these 2D networks into 3D hydro-gen-bonded framework.Complex 2 includes interesting 2D grids constructed from chiral dinuclear units throughstrong O…H—O and O…H—N hydrogen bonding,which are extended through other crystallization water mole-cules into three dimension with channels.Variable-temperature magnetic susceptibility measurements for bothcomplexes indicate the presence of weak antiferromagnetic exchange interactions between adjacent copper(Ⅱ)ions.     

D2HEDTPA和D2EHPA萃取汞(II)的研究

The extration of Hg2+ from HNO3 solution with (D2EHPA) and bis(2-ethylhexyl dithiophosphate (D2EHDTPA) was studied. The composition of extracted complex was determine by saturation and mol. ratio methods. The bonding of the extracted species is discussed on the basis of IR and NMR data. EHMO calcns. show that the extration capacities of the 2 extractants for Hg2+ are quite different.     

1D + 1D → 1D polyrotaxane, 2D + 2D → 3D interpenetrated, and 3D self-penetrated divalent metal terephthalate bis(pyridylformyl)piperazine coordination polymers

Divalent metal coordination polymers containing terephthalate (tere) and bis(4-pyridylformyl)piperazine (bpfp) show diverse and interesting two-dimensional (2D) interpenetrated, three-dimensional (3D) self-penetrated, or one-dimensional (1D) polyrotaxane topological features. Isostructural {[M(tere)(bpfp)(H(2)O)(2)]?4H(2)O}(n) phases (1, Zn; 2, Co) exhibit mutually inclined 2D + 2D → 3D interpenetration of gridlike layers. {[Cd(4)(tere)(4)(bpfp)(3)(H(2)O)(2)]·8H(2)O}(n) (3) possesses a novel 3,4,8-connected trinodal self-penetrated network with (4.6(2))(2)(4(2)6(16)8(7)10(3))(4(2)6(4))(2) topology. [Zn(2)Cl(2)(tere)(bpfp)(2)](n) (4) is the first example of a 1D + 1D → 1D polyrotaxane coordination polymer, to the best of our knowledge. Metal coordination geometry plays a crucial role in dictating the overall dimensionality in this system. Thermal decomposition behavior and luminescent properties of the d(10) configuration metal derivatives are also presented herein.     

富含缺陷的2D/2D异质结促进光催化清洁能源转化

正低维纳米材料因其特有的厚度尺寸和低维结构等特点,使其具有相应块状材料所不具备的独特性能。低维材料的显著特征就是至少有一个维度低于100 nm;零维材料,如零维纳米颗粒、量子点;一维材料,如纳米棒、纳米线和纳米纤维;二维材料如纳米片、纳米盘等。催化材料维度的降低将显著改善其量子限域效应和电子结构,进而改善其催化性能~(1–4)。基于这些思路,研究者们开始致力于研究用于光催化作用的新型二维半导体超薄材料。研究表明,     

Neutron diffraction study of uranyl oxalate [UO2(C2O4)(D2O)] · 2D2O

A powdered sample of uranyl oxalate [UO₂(C₂O₄)(D₂O)] · 2D₂O (compound I) is studied using neutron diffraction. The crystals are monoclinic, space group P2₁/c, with a = 5.608(1) Å, b = 17.016(3) Å, c = 9.410(2) Å, β = 98.9369(2)°, Z = 4, R _f = 0.042, R _I = 0.054, x ² = 1.5. The main structural units of the crystals are [UO₂(C₂O₄)(D₂O)] chains. These chains, which belong to the AK⁰²M¹ (A = UO ₂ ²⁺ ) crystal-chemical group of the uranyl complexes, lie parallel to [101]. The water molecules in the crystals of I are hydrogen-bonded into zigzag chains running along [100]. Since each third oxygen atom of the chain formed of water molecules is coordinated to the uranium atom, the uranyl oxalate chains are linked into {[UO₂(C₂O₄)(D₂O)] · 2D₂O} layers that lie normal to [010]. The layers are linked into the framework through interlayer hydrogen bonds (D₂O)O-D···O (oxalate).     

Crystal-plane-dependent photoluminescence of pentacene 1D wire and 2D disk crystals

Down to the wire: Pentacene exhibits crystal-plane-dependent photoluminescence (PL) activity, as demonstrated in highly crystalline 1D?wires and 2D?disks, which were selectively synthesized using the vaporization-condensation-recrystallization (VCR) process. Although pentacene 1D?wires and 2D?disks have identical triclinic crystal structures, PL?activity is observed only from pentacene 1D?wires owing to the presence of "PL-active" (010) planes.     

单猪屎豆碱的2D NMR

H、13C和DEPT及2DNMR(gCOSY、NOESY、gHSQC和gHMBC)方法,进一步对单猪屎豆碱的核磁共振谱进行了全归属。     

2D/2D BiOBr/g-C3N4 S型异质结光催化性能

近年来,能源短缺和环境污染严重威胁人类的可持续发展.光催化技术具有绿色环保、成本低等优势,被认为是解决上述问题的最佳途径之一,其实用化的核心是开发高效可见光催化材料.石墨相氮化碳(g-C3N4)因其物理化学性质稳定、无毒、廉价及能带适宜等特点,广泛应用于光催化领域.然而,光生载流子易复合、比表面积小等问题不利于其实际应用,构建g-C3N4基2D/2D异质结不仅能促进载流子有效分离,而且能为反应提供更多表面空间环境,是提高g-C3N4催化活性的有效途径.目前,I型和II型异质结虽能促进电荷分离,但降低了电荷参与表面反应的电势;而S型异质结电荷转移机制遵循热力学和动力学规律,能很好保留高氧化还原能力的电子和空穴,因而备受关注.当前,开发S型g-C3N4基2D/2D异质结有助于发展高效光催化体系.本文首先以三聚氰胺为前驱体,通过二次高温煅烧得到2D g-C3N4纳米片;随后,以Bi(NO3)3·5H2O和KBr为反应物,乙二胺和水为溶剂,借助室温原位自组装法获得一系列不同质量比的BiOBr/g-C3N4异质结.研究表明,BiOBr均匀分布于g-C3N4表面形成具有良好接触界面的2D/2D异质结,而且BiOBr/g-C3N4比表面积可提高至g-C3N4的2.4倍.当BiOBr与g-C3N4质量比为1.5:1时,可见光照射30 min,30 mg复合样品可将浓度为10 mg·L-1的RhB(100 mL)几乎全部降解,降解过程符合一级反应动力学,降解速率是g-C3N4的48.2倍.此外,该体系具有一定的光催化析氢活性及良好的循环稳定性.X射线光电子能谱、紫外光电子能谱、莫特肖特基、电化学阻抗谱分析及活性物种捕获等实验结果表明,由于还原性半导体g-C3N4与氧化型半导体BiOBr费米能级不同,二者接触时,电子从费米能级高的g-C3N4转移至费米能级低的BiOBr,在复合材料界面产生强的内建电场,借助带边弯曲和库仑力共同作用,形成了具有S型电荷转移途径的2D/2D BiOBr/g-C3N4异质结.在光照条件下,g-C3N4价带空穴能与BiOBr导带电子快速复合(一般认为是无用的电荷),从而使具有高反应活性的g-C3N4导带电子与BiOBr价带空穴参与表面反应,有效提高了体系的催化活性.综合本文及其他相关研究可知,在由氧化型和还原型半导体组成的异质结中,S型电荷转移机制具有一定普适性,可指导开发高效光催化体系以解决能源和环境问题.     

2D钙钛矿太阳能电池的能带调控

经过短短十年的发展,钙钛矿太阳能电池效率已经超过25%,极具商业化价值,这得益于三维(3D)钙钛矿材料具有合适的带隙、吸光系数高、电子迁移距离长等优点。但3D钙钛矿的稳定性依然是其亟待解决的问题。二维(2D)钙钛矿器件除了兼具3D钙钛矿的优异光电性质之外,其稳定性良好,是解决3D钙钛矿太阳能电池稳定性问题的一个可行方案。2D钙钛矿晶格中的疏水性大烷基胺阳离子能阻止湿气侵入的可能路径,使其成为光电器件的备选材料。由于2D钙钛矿对许多不同的有机和无机成分具有较高的耐受性,使其组成具有多样性,进而影响其能带变化。本文对2D钙钛矿的带隙调控及能带调控进行总结,希望对制备高效、稳定的低维度钙钛矿太阳能电池具有一定的指导意义。     

2D/3D ZnIn2S4/TiO2复合物的原位构筑及其提高的光催化性能

通过高温煅烧和油浴的方法构筑二维/三维(2D/3D) ZnIn₂S₄/TiO₂异质结, 应用于光催化降解罗丹明B (RhB)和四环素(TC), 来研究异质结的构筑对TiO₂可见光响应范围和光生载流子对分离效率的影响. 结果表明, TiO₂维持了MOFs的形貌, 显示窄的可见光响应范围和高的光生电荷复合率, 与ZnIn₂S₄纳米片复合后, TiO₂的比表面积增大, 光催化活性位点增多. 带隙宽度也由TiO₂的3.23 eV减小到ZnIn₂S₄/TiO₂-II的2.52 eV, 从而获得了更宽的可见光响应范围. 能带结构表明ZnIn₂S₄/TiO₂是type II型异质结, 提高了光生载流子对的分离与转移效率. 在可见光照射下, ZnIn₂S₄/TiO₂-II显示了最高的RhB光催化降解效率(93%), 分别是TiO₂和ZnIn₂S₄的18和2倍. 同时, ZnIn₂S₄/TiO₂-II也显示出比TiO₂和ZnIn₂S₄更高的TC降解效率(90%). 循环实验表明ZnIn₂S₄/TiO₂-II能保持良好的稳定性, 经5次循环实验后仍能降解83%的RhB. 研究表明基于MOFs衍生的TiO₂构筑2D/3D ZnIn₂S₄/TiO₂异质结是提高TiO₂光催化性能的一条有效途径.     

Neutron diffraction study of UO2SeO4 · 2D2O

A powdered sample of deuterated uranyl selenate dihydrate UO₂SeO₄ · 2D₂O is studied by neutron diffraction. This compound crystallizes in monoclinic space group P2₁/c; a = 6.974(1) Å, b= 8.289(2) Å, c = 11.664(2) Å, β=92.319(6)°, Z = 4, R _f = 3.14, R _I = 5.53, gC² = 2.82. The main structural units of the compound are [UO₂SeO₄(D₂O)₂] chains propagating along [100]. These chains are linked into a framework group (A = UO ₂ ²⁺ , T³ = SeO ₄ ^2? , and M¹ = D₂O) of uranyl complexes. These chains are linked into a framework by a system of hydrogen bonds formed by water hydrogen atoms of one chain and uranyl oxygen atoms of another.     

C2D2和C2H2分子键-键耦合研究

采用Morse根于描述C_2D_2分子中C－D键的伸缩振动，用谐振子描述C－C键伸缩振动，更新构造了C2D2分子的振动哈密顿，自行设计了非线性最小二乘拟合程序，并用它对C2D2分子的伸缩振动能级进行拟合，得到了基本的势能参数．理论计算与实验结果符合得很好，拟会的标准差为1.14cm－1；利用这些参数进一步计算了C2H2和C2D2的振动能级．     

Ten-Dimensional Quantum Dynamics Study of H+CH3D→H2+CH2D Reaction

The mode selectivity of the H+CH3D→H2+CH2D reaction was studied using a recently developed ten-dimensional time-dependent wave packet method.The reac-tion dynam...     

S(1D)+D2反应的立体动力学理论研究

在abinitio势能面上利用非含时量子反应散射理论研究了S(1D) D2反应在散射能为22.18kJ·mol-1时的立体动力学.计算的微分反应截面呈现弱反对称的前向后向散射,这一结果与以前的准经典结果和实验结果相一致.态分辨的极化依赖的微分反应截面和极化参数显示产物极化并非各向异性分布,这意味着在反应过程中由于势能面上存在一个深势阱从而形成了长寿命的复合物.     

S(1D)+D2反应的立体动力学理论研究

在ab initio 势能面上利用非含时量子反应散射理论研究了S(1D)+D2反应在散射能为22.18 kJ·mol-1时的立体动力学. 计算的微分反应截面呈现弱反对称的前向后向散射, 这一结果与以前的准经典结果和实验结果相一致. 态分辨的极化依赖的微分反应截面和极化参数显示产物极化并非各向异性分布, 这意味着在反应过程中由于势能面上存在一个深势阱从而形成了长寿命的复合物.