meso-四(3-氟-4-磺酸基苯基)卟啉的合成及微分分光光度法同时测定痕量铜锌

本文报道一种新的高灵敏度水溶性卟啉显色剂meso-四(3-氟-4-磺酸基苯基)卟啉的合成方法. 研究了该试剂与Cu(II)、Zn(II)的反应条件. 在PH6.4的HOAc-NaOAc缓冲介质中, Hg(II)催化下, 室温反应30min即完成. 采用四阶微分分光光度法可同时测定痕量Cu(II)、Zn(II). 表观微分摩尔吸光系数分别达8.13×10^5和1.59×10^6. 本方法灵敏度高, 选择性好, 可不用分离直接测定茶叶、血液等样品中痕量Cu(II)、Zn(II), 操作简便.     

萃取体系二相界面荷电物质传输的电化学研究 I: 邻菲咯啉体系中Ni(II)、Co(II)相转移的电化学性质

用线性电流扫描极谱、恒电流单阶跃计时电位法及等电流双阶跃计时电位法, 研究了Ni(II)、Co(II)-邻菲咯啉(phen)体系在1,2-二氯乙烷(DCE)/水界面相转移的电化学行为。同时, 研究了相转移过程的机理。结果表明, 电解前, Phen与Ni(II)或Co(II)同时在水相时, Ni(II)、Co(II)行为类同; 若电解前Phen在有机相时, Ni(II)、Co(II)的行为截然不同, 原因在于两者与Phen配位反应的动力学的差异。     

萃取体系二相界面荷电物质传输的电化学研究 I: 邻菲咯啉体系中Ni(II)、Co(II)相转移的电化学性质

用线性电流扫描极谱、恒电流单阶跃计时电位法及等电流双阶跃计时电位法, 研究了Ni(II)、Co(II)-邻菲咯啉(phen)体系在1,2-二氯乙烷(DCE)/水界面相转移的电化学行为。同时, 研究了相转移过程的机理。结果表明, 电解前, Phen与Ni(II)或Co(II)同时在水相时, Ni(II)、Co(II)行为类同; 若电解前Phen在有机相时, Ni(II)、Co(II)的行为截然不同, 原因在于两者与Phen配位反应的动力学的差异。     

萃取体系二相界面荷电物质传输的电化学研究——Ⅰ. 邻菲咯啉体系中Ni(Ⅱ)、Co(Ⅱ)相转移的电化学性质

用线性电流扫描极谱、恒电流单阶跃计时电位法及等电流双阶跃计时电位法,研究了Ni(II)、Co(II)-邻菲咯啉(Phen)体系在1,2-二氯乙烷(DCE)/水界面相转移的电化学行为.同时,研究了相转移过程的机理.结果表明,电解前,Phem与Ni(II)或Co(II)同时在水相时,Ni(II)、Co(II)行为类同;若电解前Phen在有机相时,Ni(II)、Co(II)的行为截然不同,原因在于两者与Phen配位反应的动力学的差异.     

水溶性Pt(Ⅱ)-Salen配合物的合成、表征和光催化制氢研究

本文合成了一种水溶性的Pt(II)-Salen配合物(Salen=双5-磺酸钾水杨醛合邻苯二胺席夫碱),将其用于光催化制氢.研究发现在光催化制氢体系中仅存在Pt(II)-Salen配合物和三乙胺(TEA)而没有额外加入催化剂时,在可见光照射下有氢气产生.进一步的研究表明,Pt(II)-Salen配合物在体系中既是光敏剂,又是催化剂Pt纳米粒子的前体.同时,制氢体系中除了TEA外没有使用有机溶剂.该结果为简化多组分制氢体系提供了新思路.     

Cu(II), Fe(III)与人血清白蛋白相互作用的荧光光谱研究

通过研究Cu(II),Fe(III)对人血清白蛋白(HSA)内源荧光的猝灭,探讨了Cu(II),Fe(III)与人血清白蛋白的结合机理。基于Forster非辐射能量转移机理。获得了人血清白蛋白第一类Cu(II)结合部位与214位色氨酸残基间的距离为1.8nm,并讨论了Cu(II),Fe(III)与HSA结合的差异。     

Cu(II), Fe(III)与人血清白蛋白相互作用的荧光光谱研究

通过研究Cu(II),Fe(III)对人血清白蛋白(HSA)内源荧光的猝灭,探讨了Cu(II),Fe(III)与人血清白蛋白的结合机理。基于Forster非辐射能量转移机理。获得了人血清白蛋白第一类Cu(II)结合部位与214位色氨酸残基间的距离为1.8nm,并讨论了Cu(II),Fe(III)与HSA结合的差异。     

新型支化聚乙烯亚胺螯合树脂的制备及吸附性能研究

在聚乙烯亚胺(PEI)的胺基上接枝4种不同的侧链,制备出4种新型的螯合树脂。研究这些螯合树脂对重金属离子Hg(II)、Cd(II)、Co(II)、Cu(II)、Zn(II)、Pb(II)、Mg(II)的吸附性能以及选择性吸附,并对温度对Cu(II)的最大吸附量的影响进行了研究。结果表明:新型的螯合树脂对Hg(II)有很好的吸附性能和吸附选择性,对Cu(II)、Cr(III)重金属离子也有较好的吸附性能,随着温度的升高,树脂对金属离子的吸附量逐渐上升。     

胺基酚醛型吸附树脂对染料废水的吸附与脱色

研究了胺基酚醛型吸附树脂对4种水溶性染料酸性橙II,活性红R-3B、活性黑KN-B、活性翠蓝KN-G的吸附性能。探讨了浓度、温度等因素对染料吸附性能的影响。结果表明,吸附树脂对酸性橙II具有较好的吸附;升高温度有利于吸附;随染料浓度的增大,树脂的吸附量增加。吸附树脂对4种水溶性染料的吸附速率较快,达到吸附平衡所用时间较短。对模拟废水的脱色率均达到了95.7%以上。     

钌(II)-吡啶基NNN配合物催化酮的室温(不对称)氢转移反应

合成了一种基于吡啶骨架含有苯并咪唑和手性咪唑啉基团的三齿NNN配体及其二价钌(II)配合物,通过核磁共振波谱学和X射线单晶晶体结构测定确认了钌(II)配合物的分子结构.这些配合物在室温下催化酮的氢转移反应,表现出了优异的催化活性,收率和ee值最高分别可达99%和97%.     

Analysis of ketones by selected ion flow tube mass spectrometry

A selected ion flow tube mass spectrometry (SIFT-MS) study of the reactions of H3O+, NO+ and O2+* ions with the ketones (M) 2-heptanone, 2-octanone, 2-nonanone, 2-undecanone and 2-aminoacetophenone has been conducted in preparation for studies of volatile emissions from bacteria. The H3O+ reactions all proceed rapidly via exothermic proton transfer, producing only MH+ ions that form their monohydrates when water vapour is present in the helium carrier gas. The O2+* reactions proceed rapidly via dissociative charge transfer producing parent cations M+* and some fragment ions. The NO+ reactions form the NO+M adduct ions at rates which are dependent on the pressure of the helium carrier gas. Combining the present NO+ kinetic data with those available from previous SIFT studies, the phenomenon of charge transfer complexing is clearly demonstrated. This results in adduct formation in these NO+/ketone reactions at or near the collisional rate. SIFT-MS spectra are presented to illustrate the simplicity of SIFT-MS analysis of ketones using both H3O+ and NO+ precursor ions.     

C60与甲基醚CH3OCnH2n+1的气相离子分子反应研究

自宏观量合成和分离C₆₀以来,人们不断地合成各种功能化的C₆₀衍生物.在对C₆₀化学性质的认识过程中,气相离子化学一直起着十分重要的作用。     

薄层循环伏安法研究硝基苯/水界面上离子诱导的电子转移反应

应用薄层循环伏安法研究了硝基苯/水两相界面间,且有共同离子四丁基铵TBA+存在于两相中,在有机相中的四氰化二甲基苯醌(TCNQ)与水相中的K4Fe(CN)6之间发生的反向电子转移反应。在直径为0.64cm的裂解石墨电极上用2μL硝基苯溶液使之自然扩散在电极表面形成薄层的有机相,并以此作为工作电极。对电极为铂丝(0.5mm),参比电极为Ag/AgCl电极,均置于总体积为2mL的水相中。由于共同离子TBA+的诱导,在硝基苯/水界面间,在已氧化的TCNQ+阳离子(在有机相中)与[Fe(CN)6]4-阴离子(在水相中)之间发生了反向电子转移反应。试验证明:在一定条件下,通过改变两相中共同离子的浓度,可使一些不能发生的两相界面的电子转移反应得以发生;这类电子转移反应系受界面电位差所控制。此外,还测得了在恒定的共同离子浓度比值的条件下,此两相界面电子转移反应的表观速率常数(k)为0.135cm.s-1.mol-1。     

Heavy water reactions with atomic transition-metal and main-group cations: gas phase room-temperature kinetics and periodicities in reactivity

Reactions of heavy water, D(2)O, have been measured with 46 atomic metal cations at room temperature in a helium bath gas at 0.35 Torr using an inductively coupled plasma/selected ion flow tube tandem mass spectrometer. The atomic cations were produced at ca. 5500 K in an ICP source and were allowed to decay radiatively and thermalize by collisions with Ar and He atoms prior to reaction. Rate coefficients and product distributions are reported for the reactions of fourth-row atomic cations from K+ to Se+, of fifth-row atomic cations from Rb+ to Te+ (excluding Tc+), and of sixth-row atomic cations from Cs+ to Bi+. Primary reaction channels were observed leading to O-atom transfer, OD transfer, and D2O addition. O-Atom transfer occurs almost exclusively (>or=90%) in the reactions with most early transition-metal cations (Sc+, Ti+, V+, Y+, Zr+, Nb+, Mo+, Hf+, Ta+, and W+) and to a minor extent (10%) with one main-group cation (As+). OD transfer is observed to occur only with three cations (Sr+, Ba+, and La+). Other cations, including most late transition and main-group cations, were observed to react with D2O exclusively and slowly by D2O addition or not at all. O-Atom transfer proceeds with rate coefficients in the range of 8.1 x 10(-13) (As+) to 9.5 x 10(-10) (Y+) cm3 molecule(-1)(s-1) and with efficiencies below 0.1 and even below 0.01 for the fourth-row atomic cations V+ (0.0032) and As+ (0.0036). These low efficiencies can be understood in terms of the change in spin required to proceed from the reactant to the product potential energy surfaces. Higher order reactions are also measured. The primary products, NbO+, TaO+, MoO+, and WO+, are observed to react further with D(2)O by O-atom transfer, and ZrO+ and HfO+ react further through OD group abstraction. Up to five D(2)O molecules were observed to add sequentially to selected M+ and MO+ as well as MO2+ cations and four to MO(2)D+. Equilibrium measurements for sequential D(2)O addition to M+ are also reported. The periodic variation in the efficiency (k/k(c)) of the first addition of D(2)O appears to be similar to the periodic variation in the standard free energy (DeltaG degrees) of hydration.     

中性载体ETH129推动金属离子在水/硝基苯界面的转移

本文用循环伏安法发现了中性载体ETH129(N, N, N', N'-四环己基-3-氧杂-戊二酰胺)在水/硝基苯界面推动H^+, Li^+, Na^+, Zn^2^+, Mg^2^+, Cu^2^+的离子转移,对推动离子转移过程的机理进行了探讨, 测定了相应离子的扩散系数和其配合物的稳定常数。     

Lead and mercury sensing by calixarene-based fluoroionophores bearing two or four dansyl fluorophores

A detailed study on the photophysical and complexing properties of calixarenes bearing two and four dansyl derivatives (Calix-DANS2 and Calix-DANS4) in a CH3CN/H2O mixture (60:40 v/v) is reported. Calix-DANS2 shows a high selectivity towards Hg2+ over interfering cations (Na+, K+, Ca2+, Cu2+, Zn2+, Cd2+ and Pb2+) and a sensitivity in the 10(-7) mol L(-1) concentration range. The complexation of mercury ion induces a strong fluorescence quenching due to a well-defined electron transfer process from the fluorophore to the metal center. Calix-DANS4 exhibits an extremely high affinity for Pb2+ with a high selectivity over various competing ions. The unprecedented detection limit (4 microg L(-1)) is fully compatible with the level defined by the World Health Organisation. The affinity of Calix-DANS4 for Pb2+ can be rationalized by the activation of the inert pair of electrons on Pb2+. The number of fluorophores involved in the complexation can be determined from a careful time-resolved fluorescence characterization.     

γ-Al2O3/SiO2纳米颗粒混合体系表面的酸碱性质及其对重金属离子的吸附行为

运用电位滴定技术研究了γ-Al2O3/SiO2纳米颗粒混合体系的表面酸碱性质;依据滴定数据及表面配位理论恒电容模式,利用WinSGW软件计算得出了γ-Al2O3/SiO2纳米颗粒混合体系表面的酸碱反应平衡常数:≡XOH+H+≡XOH2+(lgK1=5.06±0.05);≡XOH≡XO-+H+(lgK2=-8.45±0.10);在此基础上研究了不同pH条件下重金属离子Cu2+,Pb2+,Zn2+在γ-Al2O3/SiO2纳米颗粒混合体系表面的吸附行为,并用WinSGW软件模拟得出了Cu2+,Pb2+,Zn2+在该混合悬浮液体系中的表面配位常数:≡XOH+M2+≡XOM++H+[lgK=-2.20,-1.72,-2.90(M=Cu,Pb,Zn)].     

Ozone reactions with alkaline-earth metal cations and dications in the gas phase: room-temperature kinetics and catalysis

Room-temperature rate coefficients and product distributions are reported for the reactions of ozone with the cations and dications of the alkaline-earth metals Ca, Sr, and Ba. The measurements were performed with a selected-ion flow tube (SIFT) tandem mass spectrometer in conjunction with either an electrospray (ESI) or an inductively coupled plasma (ICP) ionization source. All the singly charged species react with ozone by O-atom transfer and form monoxide cations rapidly, k = 4.8, 6.7, and 8.7 x 10(-10) cm3 molecule(-1) s(-1) for the reactions of Ca+, Sr+, and Ba+, respectively. Further sequential O-atom transfer occurs to form dioxide and trioxide cations. The efficiencies for all O-atom transfer reactions are greater than 10%. The data also signify the catalytic conversion of ozone to oxygen with the alkaline-earth metal and metal oxide cations serving as catalysts. Ca2+ reacts rapidly with O3 by charge separation to form CaO+ and O2+ with a rate coefficient of k = 1.5 x 10(-9) cm3 molecule(-1) s(-1). In contrast, the reactions of Sr2+ and Ba2+ are found to be slow and add O3, (k >/= 1.1 x 10-11 cm3 molecule-1 s-1). The initial additions are followed by the rapid sequential addition of up to five O3 molecules with values of k between 1 and 5 x 10(-10) cm3 molecule(-1) s(-1). Metal/ozone cluster ions as large as Sr2+(O3)5 and Ba2+(O3)4 were observed for the first time.     

Synthesis and complexation properties of DTPA-N,N''-bis[bis(n-butyl)]-N'-methyl-tris(amide). Kinetic stability and water exchange of its Gd3+ complex

A novel DTPA-tris(amide) derivative ligand, DTPA-N,N'-bis[bis(n-butyl)]-N'-methyl-tris(amide)(H2L3) was synthesized. With Gd3+, it forms a positively charged [Gd(L3)]+ complex, whereas with Cu2+ and Zn2+ [ML3], [MHL3]+ and [M2L3]2+ species are formed. The protonation constants of H2L3 and the stability constants of the complexes were determined by pH potentiometry. The stability constants are lower than those for DTPA-N,N'-bis[bis(n-butyl)amide)](H3L2), due to the lower negative charge and reduced basicity of the amine nitrogens in (L3)2-. The kinetic stability of [Gd(L3)]+ was characterised by the rates of metal exchange reactions with Eu3+, Cu2+ and Zn2+. The exchange reactions, which occur via proton and metal ion assisted dissociation of [Gd(L3)]+, are significantly slower than for [Gd(DTPA)]2-, since the amide groups cannot be protonated and interact only weakly with the attacking metal ions. The relaxivities of [Gd(L2)] and [Gd(L3)]+ are constant between 10-20 degrees C, indicating a relatively slow water exchange. Above 25 degrees C, the relaxivities decrease, similarly to other Gd3+ DTPA-bis(amide) complexes. The pH dependence of the relaxivities for [Gd(L3)]+ shows a minimum at pH approximately 9, thus differs from the behaviour of Gd3+-DTPA-bis(amides) which have constant relaxivities at pH 3-8 and an increase below and above. The water exchange rates for [Gd(L2)(H2O)] and [Gd(L3)(H2O)]+, determined from a variable temperature (17)O NMR study, are lower than that for [Gd(DTPA)(H2O)]2-. This is a consequence of the lower negative charge and decreased steric crowding at the water binding site in amides as compared to carboxylate analogues. Substitution of the third acetate of DTPA5- with an amide, however, results in a less pronounced decrease in kex than substitution of the first two acetates. The activation volumes derived from a variable pressure (17)O NMR study prove a dissociative interchange and a limiting dissociative mechanism for [Gd(L2)(H2O)] and [Gd(L3)(H2O)]+, respectively.     

α-Fe2O3、γ-Al2O3、SiO2混合体系的表面配位反应

运用自动电位滴定技术分别研究了纳米α-Fe₂O₃、γ-Al₂O₃、SiO₂单一体系及三组分混合体系中氧化物表面的酸碱性质和对重金属离子Cu²⁺、Pb²⁺、Zn²⁺的吸附行为. 依据表面配位理论恒电容模式(CCM), 计算了相应的表面酸碱配位常数. 结果表明: α-Fe₂O₃/γ-Al₂O₃/SiO₂三组分混合体系的表面化学反应并非是单一体系的简单叠加, 而是存在着不同矿物表面间复杂的交互作用. 三组分表面酸碱反应平衡式和相应的酸碱反应平衡常数分别为: ≡XOH₂⁺?≡XOH+H⁺ (lgK_a1=-4.23), ≡XOH?≡XO^-+H⁺(lgK_a2=-8.41). 根据重金属离子Cu²⁺、Pb²⁺、Zn²⁺在α-Fe₂O₃/γ-Al₂O₃/SiO₂混合体系表面的吸附行为, 计算得到Cu²⁺、Pb²⁺、Zn²⁺在混合体系表面配位反应及其平衡常数如下: ≡XOH＋M²⁺?≡XOM⁺+H⁺; lgK=-2.20, -1.90, -3.20 (M=Cu, Pb, Zn).