铜（Ⅱ）－4－（吡啶－2′－甲基）－1，4，7，10－四氮杂环十三烷－11，13－二酮－α－氨基酸（5－取代邻菲罗啉）三元配合物的稳定性研究

用ｐＨ法在２５．０±０．１℃，Ｉ＝０．１ｍｏｌ·ｄｍ－３ＫＮＯ３条件下，测定铜（Ⅱ）－４－（吡啶－２′－甲基）－１，４，７，１０－四氮杂环十三烷－１１，１３－二酮－α－氨基酸（５－取代邻菲罗啉）三元配合物的稳定常数；比较了带吡啶甲基二氧四胺大环配体和二氧四胺大环配体与Ｃｕ（Ⅱ）的配位能力、配位方式；研究了该三元体系配合物稳定性与配体α－氨基酸酸碱强度之间的直线自由能关系；探讨了Ｃｕ（Ⅱ）和５－取代邻菲罗啉之间的ｄ－ｐ反馈π键以及邻菲罗啉取代基Ｈａｍｍｅｔｔ诱导效应与该三元配合物稳定性之间的关系。讨论了４－（吡啶－２′－甲基）－１，４，７，１０－四氮杂环十三烷－１１，１３－二酮和４－（喹啉－２′－甲基）－１，４，７，１０－四氮杂环十三烷－１１，１３－二酮与Ｃｕｘｐｈｅｎ所形成配合物的不同空间结构及其对配合物稳定性产生的影响。     

钴(Ⅱ)-5-取代邻菲罗啉-α-氨基酸三元配合物的稳定性研究

本文在25.0±0.1℃,I=0.1mol·dm^-3KNO₃存在下,采用pH法测得了5-取代邻菲罗啉的质子化常数以及钴(Ⅱ)与5-取代邻菲罗啉、α-氨基酸的二元、三元配合物的稳定常数。结果表明三元配合物的稳定性与5-取代邻菲罗啉的质子化常数、取代基常数均存在直线自由能关系。并用三元配合物稳定性的表征值logK_M、△logK,讨论了三元配合物的稳定性,发现钴(Ⅱ)与配体5-取代邻菲罗啉之间也存在着d-p反馈π键。该π健的强度对三元配合物稳定性有着显著影响。     

钴(II)-联吡啶-α-氨基酸的热力学和动力学研究

关于联吡啶为第一配体的二元、三元配合物的热力学和动力学性质的研究,以铜（Ⅱ）作为中心离子最为多见,而以钴（Ⅱ）作为中心离子的报导较少．实验表明,过渡金属钻（Ⅱ）能与大多数的生物配体、大π共轭体系形成相当稳定的二元、三元配合物,是生物功能模拟的一个具有应用价值的中心离子·钴（Ⅱ）卟啉可以代替铁（Ⅱ）卟啉,模拟血红蛋白、肌红蛋白[1],在生物体内起到输送氧的作用．为了充分了解钴（Ⅱ）与生物配体的配伍能力、配位方式以及其配位过程的动态行为,为推动钴（Ⅱ）配合物及其生物功能的模拟研究,本文分别采用PH电位法…     

铜(Ⅱ)-4-(喹啉-8′-甲基)-1,4,7,10-四氮杂环十三烷-11,13-二酮-α-氨基酸或5-取代邻菲罗啉两类三元配合物的稳定性研究

用 p H法在 (2 5.0± 0 .1 )℃ ,I=0 .1 mol· dm-3 KNO3 条件下 ,测定 Cu( ) - 4 - (喹啉 - 8′-甲基 ) - 1 ,4,7,1 0 -四氮杂环十三烷 - 1 1 ,1 3-二酮 -α-氨基酸或 5-取代邻菲罗啉两类三元配合物的稳定常数 ;研究了带甲基喹啉侧基大环多胺配体与 Cu( )离子的配位能力、配位方式 ;发现这两类三元体系配合物有特殊的稳定性 ;而且它们的稳定性与配体α-氨基酸及 5-取代邻菲罗啉酸碱强度之间的直线自由能关系的变化趋势相反 ;探讨了 Cu( )和 5-取代邻菲罗啉之间的 d- p反馈π键及其取代基 Hammett诱导效应的关系。     

配合物的生成热与配体的质子化热之间的直线焓关系——Ⅶ. 镍(Ⅱ)-2,2′联吡啶-N,N′-双(对位取代苯基)乙二胺的二元及三元体系

使用MS 80型Calvet微量热计, 在25 ℃, 0.1mol·dm~(-3)(NaClO_4)的50%(V/V)二氧六环溶液中, 测定了镍(Ⅱ)-N,N′-双(对位取代苯基)乙二胺二元及镍(Ⅱ)-2,2′-联吡啶-N,N′-双(对位取代苯基)乙二胺三元体系的生成热和N,N′-双(对位取代苯基)乙二胺的质子化热, 发现在二元和三元配合物的生成热、生成熵与配体的质子化热及质子化熵之间存在较好的线性关系。     

Design of Two Pyrazole-Based Sensors with Similar Configuration and Different Fluorescent Response to Anions

Two simple fluorescent anion receptors based on 1-phenyl-3-methylpyrozole-5-one-4-one phenylhydrazone (L1) and 1-phenyl-3-methylpyrozole-5-one-4-one p-nitrophenylhydrazone (L2) were designed, synthesized and characterized with ¹H NMR, COSY spectrum, ¹³C NMR, ESI-mass and elemental analyse. Interestingly, two receptors with similar configuration exhibited different anion binding behaviors in DMSO solution. The results of Job plots and ESI-mass spectrum indicate that L1 bind anions such as F⁻, AcO⁻, H₂PO₄⁻ to form 2:1 host-guest complexation, while L2 bind anions to form 1:1 host-guest complexation in the solution.     

Ratiometric and Selective Fluorescent Sensor for F<Superscript>−</Superscript> Based on Intramolecular Charge Transfer (ICT)

A simple colorimetric and ratiometric fluorescent anion sensor 1, was rationally designed and synthesized by facile one-step condensation on basis of the mechanism of intramolecular charge transfer (ICT). The sensor 1 shows more highly and selectively ability to F⁻ that induced the color changes from little yellow to purple, absorption-transferred to long wavelength and emission-transferred to short wavelength. Accordingly, ¹H NMR analysis reveals that the F⁻-induced colorimetric and fluorometric responses of 1 are simply driven by hydrogen bonding interaction between the NH protons and F⁻ ions.     

Studies of artificial hydrolytic metalloenzymes: The catalyzed carboxyester hydrolysis by copper(II), zinc(II) and cobalt(II) complexes of the tripod ligand tris(2-benzimidazylmethyl)amine

The hydrolysis kinetics of p-nitrophenyl acetate (NA) catalyzed by Cu^II, Zn^II and Co^II complexes of tris(2-benzimidazylmethyl)amine (NBT) have been studied. The hydrolysis rate is first-order in both metal(II) complex and NA. The second-order rate constants, k_cat are 0.083, 0.241 and 0.285mol^–1Ls^–1 (298K, I = 0.10molL^–1 KNO₃, 0.02molL^–1 tris buffer, 40% MeCN aqueous solution) for Zn–NBT, Co–NBT and Cu–NBT complexes, respectively. The result indicates that the hydrolytic metalloenzyme activity of different metal complexes increases with the electrophilicity of the metal ions and that the complexes, in this paper, constitute that most efficient hydrolytic metalloenzyme models reported to date. An increase in MeCN content in the solution greatly reduces the hydrolytic activity of the nucleophiles.     

A colorimetric sensor for the recognition of biologically important anions

A colorimetric anion sensor 1 based on 3-phthaloyl-N-4-nitrophenylhydrozone was synthesized and characterized. The binding ability evaluated by UV?Cvis experiment reveals that 1 can selectively recognize fluoride. Further insights into the nature of interactions between sensor 1 and anions were investigated by H NMR titrations experiments. In addition, the color changes induced by fluoride can provide a way of detection by ??naked-eye??.     

Study of kinetics and mechanism of the acid dissociation of copper(II) complex of novel C-functionalized macrocyclic dioxotetraamines

The kinetics of the acid dissociation of copper(II) complexes of novel C-functionalized macrocyclic dioxotetraamines has been studied by means of a stopped-flow spectrophotometer. The acid dissociation rate follows the law V_d = C_comkK₁K₂H ²/(1+K₁H+K₁K₂H ²). From the experimental facts we have obtained, the dissociation kinetics are interpreted by a mechanism involving the negatively charged carbonyl oxygen of the complex being rapidly protonated in a pre-equilibrium step, the rate-determining step being intramolecular hydrogen (enolic tautomer) migration (to imine nitrogen). The dissociation rate reached a plateau in the strongly acidic solution. By means of temperature coefficient method, ΔH ^φ, ΔS ^φ of the pre-equilibrium step and ΔH ^≠, ΔS^≠ of the rate-determining step were obtained. The results of 13-membered macrocyclic dioxotetraamines have been discussed. The influence of the substituents to the acid dissociation rates has also been discussed. The Bronsted type linear free energy relationships do also exist in these C-functionalized dioxotetraamine copper(II) complexes.