含酚羟基席夫碱的合成及其阴离子识别

设计和合成一个基于3,5-二叔丁基水杨醛-p-硝基苯腙含酚羟基的新型阴离子受体1. 在加入AcO^-和F^-后,受体1发生从深黄色到紫色的颜色变化. 然而,在加入其它阴离子(H₂PO₄^-, Cl^-, Br^-, I^-)没有明显的颜色变化. 通过紫外和荧光滴定研究了受体与AcO^-和F^-结合的性质.     

Au(111)上过氧化氢在碱性介质中氧化反应的pH效应

本文经过系统地研究Au(111)上过氧化氢在pH值从10到13的不同碱性溶液体系中氧化反应(HPOOR),发现随着溶液pH的增大,HPOOR的活性增大,电流电势i-iE极化曲线的斜率减小. HO₂^-是碱性溶液中HPOOR的主要反应物种,在高pH溶液下有很快的动力学反应主要是由于电极表面的正电荷与体系中的阴离子HO₂^-和OH^-等有静电相互作用的原因. 因此在溶液反应物随pH增大的时候,热力学的驱动力也加快了HO₂^-的氧化过程.     

Experimental and Theoretical Study of Hydrogen Atom Abstraction from C2H6 and C4H10 by Zirconium Oxide Clusters Anions

使用配有团簇产生和化学反应源的飞行时间质谱装置,研究了锆氧阴离子团簇Zr_xOy^-与乙烷和丁烷的反应. 在反应中发现了Zr₂O₅H^-和Zr₃O₇H^-产物. 用密度泛函理论研究了乙烷在Zr₂O₅^-上的反应通道,发现乙烷脱氢反应可以发生,从而证明观察到的产物是源于脱氢反应. 该工作揭示了锆氧负离子团簇与烷烃反应中的新通道.     

钼、钒的单一及混合溶液中离子存在形态的拉曼光谱研究

利用拉曼光谱研究了钼、钒单一及混合溶液在pH=10.0~1.0时的离子分布行为. 钼、钒离子在存在形式上存在着差异：当pH=9.0~7.5时钒主要以(VO₃)_n^n-形式存在,而钼主要为MoO₄^2-. 这一差异是目前现有的许多钼钒分离方法的基本原理. 通过将混合溶液体系的拉曼光谱与单一体系进行对比,分析得出了混合体系中离子的存在形式. 当pH低于6.5时,部分V-O-V基团中的V原子会被Mo原子取代,从而形成了钼钒杂多酸离子. 当pH=6.0~2.0时,钒主要以十聚钒酸盐形式存在;当pH=2.0~1.0时,混合溶液中的钼主要以具有七钼酸盐结构的杂多酸离子存在,而在相同pH的单一溶液中,钼的存在形式主要为Mo₈O₂₆^4-和Mo₃₆O₁₁₂^8-.     

Preparation and Characterization of Storage and Emission Functional Material of Chlorine Anion: [Ca24Al28O64]4+·(Cl-)3.80(O2-)0.10

通过碳酸钙、γ-三氧化二铝、氯化钙在氯气/氩气混合气气氛下的固态反应制备了一种氯负离子存储-发射功能材料[Ca₂₄Al₂₈O₆₄]⁴⁺·(Cl^-)_3.80(O^2-)_0.10(C12A7-Cl^-)．通过离子色谱、电子顺磁共振、拉曼光谱验证,C12A7-Cl^-材料中存储的负离子主要是氯负离子,浓度为(2.21±0.24)×10²¹ cm^-3,此外还有小部分的氧二价负离子、氧负离子、氧分子负离子．这与通过飞行时间质谱得到的结果一致：从C12A7-Cl^-材料表面发射出的负离子主要是氯负离子(大约90%),还有小部分的氧负离子和电子．材料结构和表观变化分别由X射线衍射和场发射扫描电子显微镜表征     

Br2+分子离子[1+1]双光子解离动力学

本文利用最近研制的低温离子阱-离子速度成像谱仪在冷离子束中研究了同位素质量分辨的⁷⁹Br₂⁺分子离子的[1+1]双光子激光解离动力学. 借助其1⁴Σ^-_u,3/2态为中间态使⁷⁹Br₂⁺共振吸收两个光子至4∽5 eV区域的高激发态并发生解离. 利用离子速度成像技术获得了光解产物⁷⁹Br⁺的二维速度分布和平动能释放谱. 通过平动能释放谱确定了不同解离能量处量子态分辨的解离产物通道分支比. 光碎片产物的角分布表明⁷⁹Br₂⁺分子离子的双光子解离是1⁴Σ^-_u,3/2态的ΔΩ=0平行跃迁至一个Ω=3/2高解离态发生的. 由于分子激发态中的强自旋-轨道耦合作用,高激发的四重态很可能参与到实验观测的光解过程.     

钒氧卟啉正负离子的结构畸变与电子-振动耦合的DFT研究

用PBE1PBE方法研究了钒氧卟啉一价阴离子([VOP]^-)、一价阳离子([VOP]⁺)的单态和三重态结构. 结果表明[VOP]^-和[VOP]⁺的最稳定电子态均为三重态,其未配对电子一个占据钒的d_xy轨道,另一个占据卟啉环的π轨道,因此两者均为π-自由基. 中性分子(VOP)的双重态最稳定,其未配对电子占据钒的d_xy轨道. 双重态VOP具有较高的C_4v对称性,而三重态[VOP]^- 离子由于发生姜-泰勒效应对称性降低为C_2v. 计算了[VOP]^-姜-泰勒活性振动模式的电子-振动耦合常数,并用前线KS轨道的节面分布解释了姜-泰勒畸变沿特定简正模式发生的原因. 三重态[VOP]⁺ 阳离子的卟啉环发生键长交替变化,构型畸变起源于电子态近简并引起的赝姜-泰勒效应,导致其对称性从C_4v降低为C₄,其结构变化可以用重组的前线KS轨道的节面分布解释.     

2-溴丁烷在约265 nm光解离的离子速度成像

用离子速度成像结合共振增强多光子电离技术研究了2-溴丁烷分子在264.77和264.86 nm(约265 nm)的光解离动力学．从获得的离子速度图像确定了光解产物Br和Br*碎片的速度分布和角度分布．其速度分布可以由一个窄的高斯分布拟合得到,它对应于沿着C-Br伸缩模式的直接解离．2-溴丁烷在约265nm的光解离中¹Q₁←³Q₀的非绝热跃迁在Br离子碎片的产生中起到非常重要的作用, 确定Br(²P_3/2)的相对量子产额为0.621．通过约265和约234 nm处2-溴丁烷光解的比较发现,各向异性参数和相对量子产率随着波长增加而下降,³Q₀和¹Q₁态势能面交叉几率随着波长增加而降低     

Ti+(CO2)2Ar和Ti+(CO2)n(n=3-7)络合物离子的红外光解离光谱 (cited: 1)

利用脉冲激光溅射-超声分子束载带方法制备了气相Ti⁺(CO₂)₂Ar和Ti⁺(CO₂)_n(n=3-7)络合物离子．采用红外光解离光谱研究了这些选定的质量离子的振动光谱． 对于每一种络合物离子, 在CO伸缩振动频率范围都观察到了振动峰,表明这些离子具有插入的OTi⁺CO(CO₂)_n-1结构． 对于n≦5的OTi⁺CO(CO₂)_n-1离子,其CO振动和CO₂的反对称伸缩振动频率都比自由的CO和CO₂的频率要高,表明CO和CO₂配体与中心金属离子之间主要是静电相互作用．实验结果还表明TiO⁺可以直接络合五个配体(1个CO和4个CO₂分子)．对于n=2络合物体系,除了插入的OTi⁺CO(CO₂)结构以外,还观察到了具有弯曲结构的OCO-Ti⁺-OCO异构体的存在     

化学计量的氧化钠团簇阳离子结构的离子迁移质谱法研究

本文通过离子迁移质谱法研究了氧化钠团簇阳离子(Na_nO_m⁺,n≤11)的稳定结构. 质谱结果表明化学计量组成Na(Na₂O)_(n-1)/2⁺ (n=3、5、7、9和11)系列是稳定的,并且NaO(Na₂O)_(n-1)/2⁺ (n=5、7、9和11)系列作为二级稳定系列. 为了获得这些团簇离子的结构,通过离子迁移率测量实验测定离子和氦缓冲气体之间的碰撞截面. 同时计算了这些组合物优化结构的理论碰撞截面. 结果表明,Na(Na₂O)_(n-1)/2⁺和NaO(Na₂O)_(n-1)/2⁺的结构除了n=9之外,其它具有相似结构框架. Na(Na₂O)_(n-1)/2⁺所有的化合键位于钠和氧之间. 另一方面,NaO(Na₂O)_(n-1)/2⁺中除了Na-O键之外,还存在一个O-O氧键,表明NaO(Na₂O)_(n-1)/2⁺具有过氧化物离子(O₂^2-)作为Na(Na₂O)_(n-1)/2⁺的氧化物离子(O^2-) 的替代物. Na(Na₂O)_(n-1)/2⁺和NaO(Na₂O)_(n-1)/2⁺两种稳定系列都是闭壳组合物. 这些闭壳特征对氧化钠簇阳离子的稳定性具有强烈影响.     

Recognition of H<Subscript>2</Subscript>PO<Stack><Subscript>4</Subscript><Superscript>-</Superscript></Stack> and Cu<Superscript>2+</Superscript> in Water by Luminescent Terbium Silica Xerogel

Terbium silica hybrid material with imidazole ring that can be emissive in water has been designed and showed host-guest interactions with specific ions (cations and anions). In detail, we studied the sensing abilities of this material by addition of the anions H₂PO₄^-, HSO₄^-, F^-, Cl^-, Br^- and I^- to water suspension of the derived powders. Only dihydrogen phosphate resulted in the quenching of the lanthanide luminescence (detection limit 10^-5 M). The same way was found in Cu²⁺ ions which also gave rise to luminescence quenching (detection limit 10^-5 M). More interestingly, luminescent sol-gel films were successfully prepared by the same materials and exhibited emission responses to H₂PO₄^- and Cu²⁺. For the sake of improving its mechanical property, the robust and flexible inorganic/PMMA hybrid material with sensing capability was also developed for future use.     

A Simple and Neutral Receptor Acting as a Sensitive and Switch-on Fluorescent Chemosensor for H<Subscript>2</Subscript>PO<Stack><Subscript>4</Subscript><Superscript>−</Superscript></Stack>

A novel artificial anion chemosensor 1 based on 2, 2′-di (4-nitrophenylurea-β-N-yl) -1, 1′-binaphthyl is designed and synthesized for sensing anions including halide ions and oxoanions. The fluorescent emission of the binaphthyl of receptor 1, forming the hydrogen bonding with anions as the sensing mechanism, is monitored in DMSO for detecting anions. In brief, while most of the anion chemosensors are switch-off fluorescent chemosensor, or non-fluorescent sensor, receptor 1 exhibits obviously the switch-on emission during the complexation with H₂PO₄⁻.     

Oxidation of silicon surface with atomic oxygen radical anions

The surface oxidation of silicon （Si） wafers by atomic oxygen radical anions （O- anions） and the preparation of metal-oxide-semiconductor （MOS） capacitors on the O-oxidized Si substrates have been examined for the first time. The O- anions are generated from a recently developed O- storage-emission material of [Ca24Al2sO64]^4＋·4O^- （Cl2A7-O^- for short）. After it has been irradiated by an O- anion bean： （0.5 μA/cm^2） at 300℃ for 1-10 hours, the Si wafer achieves an oxide layer with a thickness ranging from 8 to 32 nm. X-ray photoelectron spectroscopy （XPS） results reveal that the oxide layer is of a mixture of SiO2, Si2 O3, and Si2O distributed in different oxidation depths. The features of the MOS capacitor of 〈Al electrode/SiOx/Si〉 are investigated by measuring capacitance-voltage （C - V） and current-voltage （I - V） curves. The oxide charge density is about 6.0 × 10^1 cm^-2 derived from the （C - V curves. The leakage current density is in the order of 10^-6 A/cm^2 below 4 MV/cm, obtained from the I - V curves. The O- anions formed by present method would have potential applications to the oxidation and the surface-modification of materials together with the preparation of semiconductor devices.     

Negative ion photoelectron spectroscopy of 2,2’-bithiophene cluster anions, (2T)n - (n = 1–100)

Cluster anions of 2,2’-bithiophene, (2T)_n^-, were produced up to n ∼500 in the gas-phase. The energetics of the excess electron in the (2T)_n^- clusters with n =1-100 were explored by negative ion photoelectron spectroscopy. When the vertical detachment energies (VDEs) obtained from the photoelectron spectra were analyzed by a plot against n^-1/3, it has been revealed that the excess electron trapping level thus extrapolated is located at ∼0.8 eV below the conduction band minimum (i.e. LUMO) of the 2T thin film. The large slope of the VDEs vs. n^-1/3 plot suggests that the neutral 2T molecules surrounding the anion core take non-planar twisted conformations with permanent dipole moments, resulting in the exceedingly deep trapping of the excess electron in the 2T cluster anions.     

MO study of counter anions of TMTSF: Electronic structure of NO−3, BF−4, ClO−4 and FSO−3

The electronic structure and geometrical structure of NO^-₃, BF^-₄, ClO^-₄ and FSO^-₃ anions are studied by means of the ab initio molecular orbital method. According to the results obtained, the central atoms of these anions are all positively charged and the surrounding atoms negatively charged. The bonding nature of ClO^-₄ and FSO^-₃ is similar to that of XF^-₆ (X = P, As and Sb) previously studied, and has a coordination-like character. However, BF^-₄ and NO^-₃ show a covalent-like character. The ion radii of these anions are determined from the total density contour maps obtained by the calculation.     

Rational Design of Novel Benzimidazole-Based Sensor Molecules that Display Positive and Negative Fluorescence Responses to Anions

Two novel and neutral benzimidazole derivatives-based anion receptors bearing a 1,10-phenanthroline fluorophore, N,N′-di-(2′-benzimidazolyl-methylene)-1, 10-phenanthroline-2,9-diamide (1) and N,N′-di-[2′-(benzimidazolyl-2′-) ethyl-]-1,10-phenanthroline-2,9-diamide (2), which exhibited turn-on and turn-off fluorescence responses to various anions, were rationally designed and synthesized and their fluorescent response toward anions was investigated in DMSO solution. In the process of anions binding, there were two different fluorescent responses in presence of anions: a quenching of the fluorescence emission for F^- and AcO^- and an enhancement of the fluorescence emission for Cl⁻, Br⁻ and I⁻. Two different luminescent mechanisms of the receptors 1 and 2 resulting from various anions were exploited to rationalize quenching and enhancement of the fluorescence emission: a photo-induced electronic transfer mechanism (PET) and the increase of the rigidity of the host molecules, respectively. In particular, chloride could be recognized selectively from the anions tested according to changes of fluorescence spectrum. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Theory and experiment: Anion binding property of novel phenanthroline or aromatic bridged compounds

A series of artificial compounds, phenanthroline or aromatic bridged indoline derivatives, have been designed and synthesized. The interaction of these compounds with biologically important anions fluoride (F^?), acetate (AcO^?), dihydrogen phosphate (H₂PO₄^?), chloride (Cl^?), bromide (Br^?) and iodide (I^?) was determined by UV–vis, fluorescene titration and theoretical experiments. Results indicate that compound 1 (Di((1″,2″-dihydro-indol-3″-one-2″-hydrazone-1′-hydrazyl)-2′-methylene)-1,3-did-ehydebenzo) and 2 (Di((1″,2″-dihydro-indol-3″-one-2″-hydrazone-1′-hydrazyl)-2′-methylene)-1,3-didehyde-5-nitrobenzo) containing aromatic bridge do not show binding ability for various anions, and that compound 3 (Di((1″,2″-dihydro-indol-3″-one-2″-hydrazone-1′-hydrazyl)-2′-methylene)-2,9-dial-dehyde-1,10-phenanthroline) containing phenanthroline bridge shows the strongest binding ability for F^? among various anions, the moderate binding ability for AcO^? and H₂PO₄^?, and almost no binding ability for Cl^?, Br^?, I^?. The different binding ability of aromatic and phenanthroline bridged compounds may be related to the conjugative effect. What's more, the binding ability of compound 3 with F^? is not interfered by the existence of other anions. Hence, theoretical investigations explore the reasons of different binding ability between compound 3 and anions.     

Crystal structure analysis of novel complex hydrides formed by the combination of LiBH4 and LiNH2

Combination of LiBH₄ and LiNH₂ by ball milling forms the series of novel complex hydrides Li₂BNH₆, Li₃BN₂H₈ and Li₄BN₃H₁₀, depending on the combination ratios. The crystal structure of Li₄BN₃H₁₀ analyzed by synchrotron X-raydiffraction measurements is determined to be a cubic system (space group: I2₁3) with the lattice constant of a=10.673(2)Å. It should be emphasized that Li₄BN₃H₁₀ is an ionic crystal which is composed of a lithium cation Li⁺ and two different kinds of the complex anion [BH₄]^- and [NH₂]^-. These anions are located in the vertex and face-center of the cubic sub-lattice, and the lithium cation Li⁺ in the interstitial site between the anions, respectively. The other series of complex hydrides, Li₂BNH₆ and Li₃BN₂H₈, are also predicted to possess similar structures composed of a lithium cation Li⁺ and two different kinds of the complex anion [BH₄]^- and [NH₂]^-.