四-对磺酸基-苯基卟啉铁(Ⅲ)的轴向配位快速反应动力学研究

用UnionGikenRA-410温度跃变紫外可见分光光度计研究了二聚的四-对磺酸基-苯基卟啉铁[Fe(Ⅲ)TPPS₄)_D]与咪唑(Im)、2-甲基咪唑(MeIm)、2-乙基-4-甲基咪唑(EMIm)轴向配位快速反应动力学。提出了反应机理,研究了轴向配体和温度对反应的影响,应用Gauss-Newton-Marquardt方法求得基元反应的速率常数及活化参数。     

对位取代四苯基卟啉铜(Ⅱ)的生成动力学及其它金属离子的影响

本文用Shimadzu UV-240紫外可见分光光度计对Cu(Ⅱ)与对位取代四苯基卟啉H_2(p-X)TPP(X=NO_2,(Cl,H,CH_3,OCH_3)在二甲亚砜溶剂中的生成动力学及镉(Ⅱ)离子对该反应的催化作用进行了系统研究,提出了反应机理,并观察了Hg(Ⅱ)、Pb(Ⅱ)等其它金属离子对此反应的影响。发现反应速率常数及平衡常数与Hammett取代常数σ值之间呈现良好的直线自由能关系。     

尾式卟啉铁配合物与有机碱的加合作用

本文用分光光度法研究了一种新的尾式卟啉铁氯化meso-[邻-(4-二乙氨基丁酰氨基)苯基]三苯基卟啉合铁(III)[PFe(III)Cl与咪唑、苯骈咪唑、吡啶、3,5-二甲基吡啶、三乙胺、二乙胺、正丁胺的加合作用,测定了这些有机碱同卟啉铁的加合平衡常数,实验结果表明:咪唑类与卟啉铁作用一步生成2:1的加合物;吡啶类与卟啉铁作用分步生成1:1和2:1的加合物;胺类与卟啉铁作用只生成1:1的加合物,同时还发现胺类的平衡常数K与BH[+]的酸常数K之间的关系式为logK=6.45Pk-66.87。     

Ni[(C6H11O)2PS2]2与氮碱加合反应的研究

用光谱法研究了Ni[(C_6H_(11)O)_2PS_2]_2与咪唑,4-甲基吡啶,2,4-二甲基吡啶,2,2＇-联吡啶,乙胺,正丙胺,正丁胺和二乙胺的加合反应,测定了加合反应的平衡常数。平衡常数随着氮碱分子碱度增加而增大,随着氮碱分子空间位阻的增加而减小。讨论了几类氮碱加合反应平衡常数测定的处理方法。     

尾式金属卟啉配合物的研究——Ⅳ.含氮配体与尾式铁(Ⅲ)卟啉轴向配位反应热力学及其配位模式

用分光光度法研究了咪唑或吡啶类配体与5-[邻-(4-(1-咪唑基)丁氧基)苯基]-10,15,20-三苯基卟唑合铁(Ⅲ)氯化物[[Fe~Ⅲ(ImTPP)]Cl]和5-[对-(4-(3-吡啶氧基)丁氧基)苯基]-10,15,20-三苯基卟啉合铁(Ⅲ)氯化物[[Fe~Ⅲ(PyTPP)]Cl]两种尾式铁(Ⅲ)卟啉的轴向加合作用,测定了平衡常数、热力学参数及含氮配体的加合分子数.结果表明,[Fe~Ⅲ(PyTPP)Cl与[Fe~Ⅲ(TPP)]Cl相类似,均与咪唑、吡啶类配体生成1:2低自旋六配位加合物.含氮配体与[Fe~Ⅲ(ImTPP)]Cl的轴向加合反应平衡常数比与[Fe~Ⅲ(TPP)]Cl相应的平衡常数大10～10~3倍,这是因为含氮配体与[Fe~Ⅲ(ImTPP)]Cl的轴向配位诱导了尾端咪唑基与配合物中的Fe~Ⅲ离子的轴向配位,这种配位模式增强了含氮配体与Fe~Ⅲ离子的键合;尾端咪唑基与配合物中的Fe~Ⅲ离子配位的模式得到了UV—vis、~1H NMR及EPR实验数据的进一步证实.     

二乙胺基尾式卟啉锰(Ⅲ)的性质研究(Ⅱ)——含氮有机碱与尾式卟啉锰(Ⅲ)配合物的轴向反应

采用光谱技术研究了一种新型尾式锰(Ⅲ)卟啉--氯化meso--[邻-(4-二乙胺基丁酰胺基)苯基]三苯基卟啉合锰(Ⅲ)[筒作PMn(Ⅲ)Cl]与有机碱的轴向反应,通过光谱滴定法测定了轴向反应在苯溶剂中的平衡常数.讨论了影响反应的因素.结果表明,这种尾式锰(Ⅲ)卟啉与脂肪胺的反应是氧化还原反应,与吡啶的反应是不完全的氧化还原反应,与咪唑的反应是轴向加合反应.     

8-(4-取代苯基)-10,10-二甲基-6-苯基-10 H-吡啶并[1,2-a]吲哚盐的合成

2,3,3-三甲基-3H-吲哚高氯酸盐与取代查耳酮在异戊醇中反应,得到五种新的8-(4-取代苯基)-10,10-二甲基-6-苯基-10 H-吡啶并[1,2-a]吲哚盐[R=Me_2N-(3a),R=MeO-(3b);R=Br-(3c),R=H-(3d);R=O_2N-(3e)]通过元素分析和光谱测定确证了产物的结构。紫外光谱表明,λ_(max)与R有关,其次序为Me_2N—>MeO—>Br—>H—>O_2N—     

对位取代四苯基卟啉铜(II)的生成动力学及其它金属离子的影响

本文用Shimadzu UV-240紫外可见分光光度计对Cu(Ⅱ)与对位取代四苯基卟啉H_2(p-X)TPP(X=NO_2, (Cl,H,CH_3,OCH_3)在二甲亚砜溶剂中的生成动力学及镉(Ⅱ)离子对该反应的催化作用进行了系统研究, 提出了反应机理, 并观察了Hg(Ⅱ)、Pb(Ⅱ)等其它金属离子对此反应的影响。发现反应速率常数及平衡常数与Hammett取代常数σ值之间呈现良好的直线自由能关系。     

锌卟啉-蒽醌-2-磺酸酯轴向配位性能研究

本文以三种锌卟啉-蒽醌-2-磺酸酯为主体化合物,利用紫外-可见光谱法研究主体化合物与客体咪唑、吡啶、N-甲基咪唑进行的轴向配位反应,结果表明:①对于同一主体,客体的配位能力为:N-甲基咪唑咪唑吡啶;②对于同一客体,主体的配位能力是5-(苯基-4-(蒽醌-2-磺酸酯))-10,15,20-三(4-氯苯基)卟啉锌5-(苯基-4-(蒽醌-2-磺酸酯))-10,15,20-三苯基卟啉锌5-(苯基-4-(蒽醌-2-磺酸酯))-10,15,20-三(4-甲氧基苯基)卟啉锌;③实验结果经计算表明主客体之间以摩尔比1∶1配位,随着温度的升高反应的平衡常数逐渐减小,焓变Δ_rH_m~Θ0,反应是放热反应。     

辅酶B_(12)模型化合物的研究(V)RCo(Salen)L配合物Co—C键断裂的动力学

运用光度法研究了RCo(Salen)L配合物在甲醇中热分解反应动力学;测定了Co—C键断裂的速率常数及活化能,得到表观速率常数顺序为i-C3H7>i-C4H9>n-C4H9>n-C3H7>C2H5,活化能顺序为i-C3H7相似文献   

一个纳入活化络合非平衡效应的TST公式体系

在唯象理论的层次上评述了活化络合体系的非平衡性引起的非平衡统计问题;通过分析活化络合过程的耗散与涨落对反应速度的影响,提出了一个纳入了活化络合过程非平衡效应的TST公式体系代替活化络合平衡常数,建立了活化络合耗散函数与反应速度的关系.同时讨论了影响反应活化络合进程耗散-涨落的诸因素所导致的速度常数统计漂移     

Tetrahydroxyazon SCl as a new analytical reagent for determining copper(II)

2,2′,3,4-Tetrahydroxy-3′-sulfo-5-chloroazobenzene was synthesized from pyrogallol and 2-aminophenol-5-chlorobenzenesulfonic acid. The complexation of copper(II) with this reagent was studied. A homoligand compound of the stoichiometry 1: 1 was obtained at pH 2. The optimum conditions for complexation were found and the equilibrium constant of the reaction was calculated. The selectivity of the reaction was studied and the stability constant of the complex was evaluated. Procedures were developed for the photometric determination of copper in alloys and soils.     

Dynamic study of interaction between beta-cyclodextrin and aspirin by the ultrasonic relaxation method

A single ultrasonic relaxational phenomenon was observed in aqueous solutions containing both beta-cyclodextrin (beta-CD) as host and nonionized or ionized acetylsalicylic acid (aspirin) as guest. The observed relaxation was responsible for a dynamic complexation reaction between beta-CD and aspirin molecules, concomitant with a volume change during the reaction. The kinetic and equilibrium constants for the complexation in the acid (nonionized) form of the aspirin system were derived from the guest concentration dependence of the relaxation frequency. The equilibrium constant for the carboxylate (ionized) form of aspirin was determined from the concentration dependence of a maximum absorption per wavelength, and the rate constants were calculated by using the determined equilibrium constant and the observed relaxation frequencies, which remained nearly almost constant over the concentration range studied. The results showed that the effect of charge on the aspirin molecule was reflected only in the dissociation process from the beta-CD cavity, while no remarkable change was seen in the association process whose rate was diffusion controlled. The results could be explained on the basis of the difference of the hydrophobic moieties in the two guests that were included in the host cavity. The results of the standard volume change for the complexation reaction were closely related to the number of expelled water molecules originally located in the beta-CD cavity and the volume of the aspirin molecule incorporated into the beta-CD cavity.     

Influence of ligand structure and solvent effects on complexation of neutral guests by several crown ethers

The formation of complexes between crown ethers and acetonitrile, chloroform, and nitromethane were investigated in carbon tetrachloride at 25°C. A significant influence of the ring size on the selectivity of the host is evident. The host 18-crown-6 forms complexes for which the reaction enthalpy and entropy are quite high. Host molecules with benzene side groups form complexes of lower reaction enthalpy and entropy and therefore the complexes formed are less stable than that of the analogous crown ethers without aromatic groups. Solvent effects on the stability constant K, the reaction enthalpy H, and the reaction entropy S were studied for the complexation of malonitrile by 18-crown-6. The reaction enthalpy and entropy values change in accordance with the dielectric constant of the solvent used, but no overall effect on complex stability with change in solvent dielectric constant was observed.     

Equilibrium constants between boron trifluoride etherate and carbonyl compounds in chloroform solution

[reaction: see text] Equilibrium constants for boron trifluoride complexation with carbonyl compounds relative to diethyl ether were determined in CDCl(3). With benzaldehyde the equilibrium constant is 0.208. There is a 1.28-fold preference for BF(3) bonding to benzaldehyde-D over benzaldehyde-H. The rho(+) value for complexation with substituted benzaldehydes is -2.0. Equilibrium constants with cyclohexanone and isobutyraldehyde were found to be not very different from those predicted from the heats of addition of BF(3) relative to that for diethyl ether. The heats of addition can be correlated with Taft's beta values and with beta' values.     

Kinetic studies of complexation reactions of water-soluble hydrazones with nickel(II) and palladium(II) ions

The kinetics of complexation reactions of five water-soluble heterocyclic hydrazones with nickel(II) and palladium(II) ions have been investigated by stopped-flow spectrophotometry. Rates of complexations with nickel(II) and palladium(II) in the absence of chloride ion were found to be proportional to the first order of the ligand and metal ion concentrations and to the inverse first order of the hydrogen ion concentration except for the complexation of alpha-(2-benzimidazolyl)-alpha-(5-nitro-2-pyridyl)hydrazono-3-toluenesulfonic acid with palladium(II). Rates of complexation with palladium(II) in the presence of chloride ion were best described by a two-term expression, both terms being first order in the palladium ion and ligand concentrations and inverse first order in the hydrogen ion concentration. The first term has zero dependence of the chloride ion concentration, whereas the second is first order with respect to the chloride ion concentration. The rate constant for each complexation reaction was determined. The complexation of the hydrazones with nickel(II) was estimated to go according to an Eigen mechanism and that with palladium (II) according to the associative mechanism.     

Kinetics of the post-column complexation reaction of Cu(II) with N-formylmethionyl chemoattractant and chemotactic peptides

The N-formylmethionyl peptides comprise an important class of peptides that activate neutrophils to attack microbial invaders. The post-column reaction of Cu(II) with peptides following their separation leads to electroactive complexes that are detectable with electrochemical detection. The need to minimize post-column band spreading puts constraints on the time allowed for the complexation reaction to occur. For most peptides, the reaction rate is rapid, however, for peptides without a free terminal amine the reaction rate is slower. In order for this detection scheme to be sensitive to so-called N-blocked peptides, the rate law and the influence of buffers need to be understood.The kinetics of the complexation of Cu(II) with several N-blocked chemoattractant and chemotactic peptides are similar. One N-blocked peptide, N-f-MLF, has been studied in detail. Two parallel paths have been found for the complexation reaction. The reaction at the amide terminus is first order in [peptide] and [OH(-)]. The reaction at the carboxylate terminus is first order in [peptide], [Cu(II)], and total carbonate at constant pH. The response of the rate as pH is changed reveals that bicarbonate ion is the active species.     

Inclusion complexes of phosphorylated daidzein derivatives with β-cyclodextrin: Preparation and inclusion behavior study

In the present work the feasibility of β-cyclodextrin in complexation was explored, as a tool for improving the solubility and biological ability of daidzein derivatives. A series of phosphorylated daidzein derivatives featuring different chain lengths were synthesized through a modified Atherton-Todd reaction and their inclusion complexes with βCD were prepared by coprecipitation method. The inclusion complexation behavior was studied by fluorescence, UV, FT-IR, MS and (1)H NMR. The results showed that only phosphorylated daidzein derivative carrying small substituent group ((C(2)H(5)O)(2)PO) entered the cavity of βCD and formed 1:1 inclusion complex. The formation constant was 175(mol/L)(-1).     

Template mechanism and kinetics for the complexation of ninhydrin with copper (II) complexes of asparagine and serine

Ninhydrin has been found to form a 1:1 complex with Cu(II) complexes of asparagine and serine. The kinetics of the complexation reaction has been studied spectrophotometrically in acetate buffer. The effect of the [ninhydrin], pH, and temperature on the reaction rate of the reaction was studied. The reaction follows fractional-order kinetics with respect to ninhydrin and first-order with respect to asparagine-Cu(II) and serine-Cu(II), respectively. The reaction proceeds through the coordination of ninhydrin with the same Cu(II) of asparagine and serine complexes. The results are best accounted by the “Template mechanism” for the inner sphere complexation. The values for the inner sphere complex formation constant were also calculated from the kinetic data. The role of Cu(II) in this reaction is to inhibit the breaking of C(SINGLEBOND)C (evolution of CO₂) as well as stabilize the C(DOUBLEBOND)N of Schiff base. On the basis of observed results, probable mechanism has been proposed. © 1996 John Wiley & Sons, Inc.     

Solvent effects on SN2 reaction between substituted benzyl chloride and chloride ion

The effects of solvent on S_N2 reaction between some substituted benzyl chlorides and chloride ion have been investigated by DFT and ab initio methods using the polarizabale continuum model. The activation energies are higher in the solution media relative to the gas phase and grow by the increase in the dielectric constant of solvent. The complexation energies in solution media are smaller than those in the gas phase and reduce with increasing the dielectric constant. The energy data are in good agreement with the geometrical parameters and substituent constants. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011