喹啉基对二氧四胺大环铜配合物结构和性质的影响

喹啉基对二氧四胺大环铜配合物结构和性质的影响卜显和，安道利，朱志昂，张智慧，陈荣悌（南开大学化学系，天津３００００７１）二氧四胺大环（ｍａｃｒｏｃｙｃｌｉｃｄｉｏｘｏｔｅｔｍａｍｉｎｅ）配体因其独特的结构特点和功能而受到广泛的重视和关注［１］。通过在...     

配合物的直线自由能关系（ⅩⅦ）—铜（Ⅱ）—二氧四胺大环—α—…

用ｐＨ法在２５．０±０．１℃、Ｉ＝０．１ｍｏｌ／Ｌ ＫＮＯ３条件下研究了铜（Ⅱ）与１２－（２＇－羟基－５取代苄基）－１，４，７，１０－四氮杂环十三烷－１１，１３－酮－α－氨基酸所形成的竞争性三元混配型配合物的稳定性，测定了该体系的二元、三元配合物的稳定常数，并探讨了大环配体的取代基效应及二元、三元配合物的结构。     

铜(Ⅱ)-8-羟基喹啉取代二氧四胺大环-α-氨基酸三元体系热力学稳定性研究

合成了两个8-羟基喹啉取代的双功能二氧四胺大环配体L1和L2,并在25℃下研究了Cu-大环配体-α-氨基酸三元体系的热力学稳定性.根据实验数据对滴定体系物种的构型进行了分析和指认,并发现Cu(Ⅱ)-8-羟基喹啉-α-氨基酸三元体系中也存在良好的直线自由能关系.     

7-取代-8-羟基喹啉的合成

由2-氯辛烷与8-羟基喹啉钠反应制得7-(1′-甲基庚基)-8-羟基喹啉.用长碳链脂肪醛在碱性介质中与8-羟基喹啉反应,合成了一系列7-烯基-8-羟基喹啉(1);对不同结构长碳链脂肪醛合成作了研究.     

取代8-羟基喹啉钌络合物催化Friedl?nder反应合成喹啉衍生物

Friedl?nder喹啉合成法是以邻胺基芳基醛或酮与有α-亚甲基的酮环化制备喹啉的反应,报道了一种喹啉钌络合物催化Friedl?nder法合成喹啉的方法.首先,以8-羟基喹啉钌络合物为催化剂,对模板反应邻氨基苯甲醇和苯乙酮合成2-苯基喹啉进行了反应条件优化实验.重点对比研究了8-羟基喹啉钌络合物配体上不同取代基对反应收率的影响,其中5-甲基-8-羟基喹啉(1e)钌络合物催化邻氨基苯甲醇和苯乙酮合成2-苯基喹啉获得了73%的最高收率.结合IR, UV以及密度泛函理论(DFT)计算讨论了配体结构与催化性能之间的关系.提出了β-H消除形成醛过渡态,交叉aldol反应再亚胺环化,最后脱水生成目标产物的可行机理.以(1e)₃Ru为催化剂,在优化的反应条件下进行了底物扩展研究,以69%～94%的收率合成了32个不同取代的喹啉衍生物,验证了方法的普适性.     

配位化学中的直线自由能关系XXII: 铜(II)-α-氨基酸-二氧四胺大环三元体系

用pH法在25.0±0.1℃, I=0.1 mol.dm^-^3 KNO3条件下研究了铜(II)-α-氨基酸-13-(2'-羟基-3', 5'-取代苄基)-1, 4,8, 11-四氮杂环十四烷-12, 14-二酮竞争性三元混配型配合物的稳定性。测定了该体系的三元配合物的稳定常数, 并讨论了二氧四胺大环配体的环空腔大小对三元配合物的构型及稳定性的影响以及大环配体上取代基对三元配合物的影响。     

功能取代二氧四胺大环金属超分子配合物的溶液热力学性质研究

利用简单步骤合成了8-羟基喹啉取代的二氧四胺大环配体,此类配体含有两个独立的螯合基团,在适当情况下能分别与金属离子配位.在(25.0±0.1)℃,I=0.1mol/LNaNO₃条件下,用pH法测定了n(配体):n(金属离子)=2:3的二元配合物的稳定常数,并从滴定数据讨论了物种的可能构型.     

配位化学中的直线自由能关系XXII: 铜(II)-α-氨基酸-二氧四胺大环三元体系

用pH法在25.0±0.1℃, I=0.1 mol.dm^-^3 KNO3条件下研究了铜(II)-α-氨基酸-13-(2'-羟基-3', 5'-取代苄基)-1, 4,8, 11-四氮杂环十四烷-12, 14-二酮竞争性三元混配型配合物的稳定性。测定了该体系的三元配合物的稳定常数, 并讨论了二氧四胺大环配体的环空腔大小对三元配合物的构型及稳定性的影响以及大环配体上取代基对三元配合物的影响。     

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pH法在(25.0±0.1)℃,I=0.1mol·dm^-3KNO₃条件下,测定Cu(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常数;研究了带甲基喹啉侧基大环多胺配体与Cu(Ⅱ)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(Ⅱ)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。     

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.     

The determination of the second dissociation constant of sulfuric acid

The second dissociation constant of sulfuric acid is determined in 1M NaClO₄ at 25°C using an electrochemical cell without liquid junction consisting of a glass and a perchlorate electrode. By taking into account the association between the Na⁺ and SO ₄ ^2– ions an average value of 0.0184±0.0005 is found using three different methods. This corresponds with an apparent acidity constant KA ₂ ^* of 0.095±0.003     

Hydrothermal reactions of lactic acid catalysed by group: VIII Metal complexes

At 220–250°C, in the presence of [PtH(PEt₃)₃]⁺ in aqueous solution, α-hydroxypropanoic acid (lactic acid) is converted into propanoic, propenoic, β-hydroxypropanoic, pyruvic and acetic acids. The reactions catalysed by [PtH(PEt₃)₃]⁺ appear to be double bond hydration and hydrogenation, alcohol dehydration, transfer hydrogenation, decarbonylation and the water-gas shift reaction. Propenoic acid under similar conditions gives similar products. Attempts to catalyse the dehydrocarboxylation of lactic acid using PdCl₂, [PtCl₂(PPh₃)₂], [IrH(CO)(PPh₃)₃] and [Ni(CO)₂(PPh₃)₂] were partially successful, although competing disproportionation gave a wide range of products.     

Syntheses,structures and catalytic activity for Friedel-Crafts reactions of substituted indenyl rhenium carbonyl complexes

The complexes [(η⁵-C₉H₆R)Re(CO)₃] [R = ⁿBu (8), ^tBu (9), CH(CH₂)₄ (10), Ph (11), Bz (12), 4-methoxyphenyl (13), 4-chlorophenyl (14)] were synthesized by refluxing substituted indenyl ligands [C₉H₇R] [R = ⁿBu (1), ^tBu (2), CH(CH₂)₄ (3), Ph (4), Bz (5), 4-methoxyphenyl (6), 4-chlorophenyl (7)], and Re₂(CO)₁₀ in decalin. The molecular structures of 9, 10, 12, and 13 were determined by X-ray diffraction analysis. These four crystals have similar molecular structures of the mononuclear carbonyl complex. In each of these molecules, Re is η⁵-coordinated to the five-membered ring of the indenyl group. Complexes 8–14 have catalytic activity for Friedel-Crafts reactions of aromatic compounds with a variety of alkylation and acylation reagents. Compared with traditional catalysts, these mononuclear metal carbonyl complexes have obvious advantages such as high activities, mild reaction conditions, high selectivity, and environmentally friendly chemistry.     

Determination of the degree of electrolytic dissociation of perchloric acid by vapor pressure

Analysis of the published data on the vapor pressure and degree of electrolytic dissociation of perchloric acid revealed that the molar fraction of nondissociated HClO₄ is determined by the Raoult—Henry law in a wide range of acidimetric concentrations and temperatures. The degree of dissociation of perchloric acid was calculated from its thermodynamic activity. The results of calculations agree satisfactorily with the known spectroscopic data.     

Monitoring of enzyme catalysed reactions by Fourier transform Raman spectrometry

Esterification of mandelic acid catalysed by Candida antarctica lipase B was studied by Fourier transform (FT) Raman spectrometry in non-aqueous medium. It was found that there is a strict correlation between the intensity of the Raman scattering and the activity of the enzyme. FT-Raman spectrometry seems to be a fast and reliable method for selecting the appropriate enzyme and for determining the optimal enzyme water content. In addition, valuable information can be obtained from the spectra regarding the mechanism of enzyme–substrate bonding.     

乙酸和一氯乙酸电离常数的高效毛细管区带电泳法测定

首次建立了测定一氯乙酸和乙酸的电离常数的高效毛细管区带电泳新方法.该方法利用中性标记物和电流突跃两种方法来标记电渗流,通过测定乙酸和一氯乙酸在一定pH的缓冲溶液中的电泳淌度,结合数据回归分析拟合,求得乙酸和一氯乙酸的电离常数;所得数据和文献报道值较为接近.总体而言,毛细管区带电泳法可简单、快速、可靠地用于测定待测化合物的电离常数.     

Thermal dissociation of iron carbonyls during growth of iron whiskers

Methods for the preparation of iron whiskers in chemical transport reactions of thermal dissociation of iron penta- and dodecacarbonyls and carbidocarbonyl clusters Fe₅C(CO)₁₅ were described. The morphology, structure, and chemical composition of the whiskers were studied. The main factors determining the growth rate and mechanical properties of the whiskers were revealed. A model for the mechanism of thermal dissociation of iron carbonyls was proposed. This process was shown to be a chain radical ion reaction initiated via the scheme of activating complex formation. Analogies between the thermal dissociation of iron carbonyls in the adsorption layer and the known radical ion processes in the liquid and gas phases were found.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1826–1836, September, 2004.     

Synthesis and electrochemical studies of phenylazo substituted tetraaza macrocyclic complexes of Ni(II)

Synthesis and characterization of some phenyl azo substituted tetraaza macrocyclic complexes of Ni(II) are reported. Electrochemical behaviour of these macrocyclic complexes has been examined using polarographic, voltammetric and spectroscopic techniques. These studies show that both the ligand and the metal are electrochemically active. The electrochemical behaviour of the azo function has been shown to occur through a single four-electron process. When a nitro group is also present, the nitro function of the azo moiety is reduced in a six-electron cathodic wave.     

Structure and dissociation energy of weakly bound H (n = 5−8) complexes

The geometrical parameters, vibrational frequencies, and dissociation energies for H (n = 5–8) clusters have been investigated using high level ab initio quantum mechanical techniques with large basis sets. The highest level of theory employed in this study is TZ2P CCSD(T). The C₁ structure of H is predicted to be a global minimum, while the C_s structure of H is calculated to be a transition state. Harmonic vibrational frequencies are also determined at the DZP and TZ2P CCSD levels of theory. The dissociation energies, D_e, for H (n = 5–8) have been predicted using energy differences at each optimized geometry, and zero‐point vibrational energies (ZPVEs) are considered to compare with experimental values. The dissociation energies (D_o) have been predicted to be 1.69, 1.65, 1.65, and 1.46 kcal · mol for H, H, H (C₁ symmetry) and H, respectively, at the TZ2P CCSD(T) level of theory. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007