四氮杂大环镍(Ⅱ)配合物[Ni(TIM)](ClO4)2催化的新型B-Z振荡反应

本文报道了一种以四氮杂大环四烯镍(Ⅱ)配合物[Ni(TIM)](ClO4)2为催化剂,柠檬酸为有机底物的硫酸环境的新型的B-Z振荡反应体系。讨论了不同浓度的溴酸钠、硫酸、柠檬酸对振荡周期(tp)、振幅(A)、振荡次数(n)的影响,发现振荡周期tp与溴酸钠、硫酸、柠檬酸的浓度有关,关系表达式:tp(s)∝C0-2.003(NaBrO3)C0-2.881(H2SO4)C0-3.16(Citric acid)。研究了各种还原剂、自由基抑制剂、Ag+、Hg2+对该振荡反应的不同程度的影响。最后提出了该反应的反应机理。     

Chiral Recognition of Racemic Proline based on Chiral Macrocyclic Nickel(II) Complex: Synthesis and Crystal Structures

The reactions of dl‐proline with chiral macrocyclic Ni^II complex [Ni(SS‐L)](ClO₄)₂ in acetonitrile/water gave a six‐coordinate enantiomer formulated as [Ni(SS‐L)(l‐Pro)](ClO₄)₂ · H₂O ( 1 ). Another enantiomer of [Ni(RR‐L)(d‐Pro)](ClO₄)₂ · H₂O ( 2 ) was obtained when [Ni(RR‐L)](ClO₄)₂ was used (L = 5,5,7,12,12,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane, Pro = proline). Single‐crystal X‐ray diffraction analyses of complexes 1 and 2 revealed that the Ni^II atom has a distorted octahedral coordination arrangement, being coordinated by four nitrogen atoms of L in a folded configuration, plus two carboxylate oxygen atoms of proline in mutually cis positions. Complexes 1 and 2 are supramolecular stereoisomers, which are constructed with hydrogen bonding linking of [Ni(SS‐L)(l‐Pro)]²⁺ and [Ni(RR‐L)(d‐Pro)]²⁺ monomers to form one‐dimensional zigzag chains. The homochiral natures of complexes 1 and 2 were confirmed by solid CD spectroscopy.     

Structures of Nickel(II) and Copper(II) Complexes of 14-Membered Macrocyclic Quadridentate Ligands

The structures of 41 Ni(II) and 17 Cu(II) complexes of macrocyclic quadridentate ligands have been analyzed, and are discussed about bond lengths, bond angles, conformations, and configurations, upon which many conclusions are formed. The inter- or intra-molecular hydrogen bonds exist among ligands and hydrates in many compounds and play an important role in the structures. There are exhibited two distinct peaks on the histogram of the average Ni-N distances, corresponding to four coordination and six coordination; these average Ni-N distances are 1.95(4) Å and 2.10(5) Å, respectively. The most probable structures of Ni(II) macrocyclic compounds have coordination number six for the metal ion, chair forms for six-membered rings, planar structure for the metal ion and the four donor atoms of the quadridentate ligand and an inversion center at the central metal ion.     

Ni2L配合物的热稳定性和电化学研究

用金属离子作模板通过N－氧化吡啶－2，6－二甲醛与1，3－丙二胺缩合得到了新型大环水溶性希夫碱金属配合物Ni2LCl6·C2H5OH·10H2O，对其进行了元素分析、红外光谱、电化学及热稳定性能的研究．结果显示：Ni2L配合物的电极反应可以认为是一个双电子传输过程，并且电极过程是一个不可逆过程，求得它的扩散系数为4．07×10－6cm2·s-1．该配合物的稳定性较好，约在563℃配合物发生分解，失去有机基因，生成氧化物．     

Kinetic Study of the Ce(III)‐, Mn(II)‐, or Ferroin‐Catalyzed Belousov‐Zhabotinsky Reaction with Allylmalonic Acid

In a stirred batch experiment and under aerobic conditions, ferroin (Fe(phen)₃²⁺) behaves differently from Ce(III) or Mn(II) ion as a catalyst for the Belousov‐Zhabotinsky (BZ) reaction with allylmalonic acid (AMA). The effects of bromate ion, AMA, metal‐ion catalyst, and sulfuric acid on the oscillating pattern were investigated. The kinetics of the reaction of AMA with Ce(IV), Mn(III), or Fe(phen)₃³⁺ ion was studied under aerobic or anaerobic conditions. The order of reactivity of metal ions toward reaction with AMA is Fe(phen)₃³⁺ > Mn(III) > Ce(IV) under aerobic conditions whereas it is Mn(III) > Ce(IV) > Fe(phen)₃³⁺ under anaerobic conditions. Under aerobic or anaerobic conditions, the order of reactivity of RCH(CO₂H)₂ (R = H (MA), Me (MeMA), Et (EtMA), allyl (AMA), n‐Bu (BuMA), Ph (PhMA), and Br (BrMA)) is PhMA > MA > BrMA > AMA > MeMA > EtMA > BuMA toward reaction with Ce(IV) ion and it is MA > PhMA > BrMA > MeMA > AMA > EtMA > BuMA toward reaction with Mn(III) ion. Under aerobic conditions, the order of reactivity of RCH(CO₂H)₂ toward reaction with Fe(phen)₃³⁺ ion is PhMA > BrMA > (MeMA, AMA) > (BuMA, EtMA) > MA. The experiment results are rationalized.     

Synthesis and Crystal Structure of Two Succinato‐Bridged Macrocyclic Nickel(II) Complexes

Two dinuclear succinato‐bridged nickel(II) complexes [Ni(RR‐L)]₂(μ‐SA)(ClO₄)₂ ( 1 ) and [Ni(SS‐L)]₂(μ‐SA)(ClO₄)₂ ( 2 ) (L = 5, 5, 7, 12, 12, 14‐hexamethyl‐1, 4, 8, 11‐tetraazacyclotetradecane, SA = succinic acid) were synthesized and characterized by EA, Circular dichroism (CD), as well as IR and UV/Vis spectroscopy. Single crystal X‐ray diffraction analyses revealed that the Ni^II atoms display a distorted octahedral coordination arrangement, and the succinato ligand bridges two central Ni^II atoms in a bis bidentate fashion to form dimers in 1 and 2 . The monomers of {[Ni(RR‐L)]₂(μ‐SA)}²⁺ and {[Ni(SS‐L)]₂(μ‐SA)}²⁺ are connected by O–H ··· O and N–H ··· O hydrogen bonds into a 1D right‐handed and left‐handed helical chain along the b axis, respectively. The homochiral natures of 1 and 2 are confirmed by the results of CD spectroscopy.     

Simultaneous Determination of Nickel(II) and Cobalt(II) by Second-Derivative Spectrophotometry

4-(2-Pyridylazo) resorcinol, PAR, is shown to be useful for simultaneous determination of cobalt(II) and nickel(II) using second-derivative spectrophotometric method with controlled experimental parameters. This method allows the determination of 0.20-1.25 ppm of nickel(II) and 0.25-1.50 ppm of cobalt(II) in mixtures with good precision and accuracy. This method has advantages of simplicity, speed and requires no prior separations.     

Synthesis,Characterization, and DNA Binding Studies of a Nickel(II) Complex Containing the 1,3‐Bis(1‐propylbenzimidazol‐2‐yl)‐2‐oxapropane

A complex of formula [Ni(pobb)₂](pic)₂, (pobb = 1,3‐bis(1‐propylbenzimidazol‐2‐yl)‐2‐oxapropane, pic = 2,4,6‐trinitrophenol), has been synthesized and structurally characterized by physico‐chemical and spectroscopic methods. The crystals crystallize in the monoclinic system, space group C2/c, a = 25.766(11) Å, b = 14.943(7) Å, c = 19.543(14) Å, α = 90°, β = 129.722(4)°, γ = 90°, Z = 4. The coordination environment around nickel(II) atom can be described as a distorted octahedral geometry. The interactions of the ligand pobb and the nickel (II) complex with calf thymus DNA (CT‐DNA) are investigated by using electronic absorption titration, ethidium bromide‐DNA displacement experiments and viscosity measurements. The experimental evidence indicated the compounds interact with calf thymus DNA through intercalation.     

Syntheses and crystal structures of nickel(II), copper(II), and zinc(II) complexes with a biphenyl-bridged bis(pyrrole-2-yl-methyleneamine) ligand

The reactions of nickel(II), copper(II), and zinc(II) acetate salts with a potentially tetradentate biphenyl-bridged bis(pyrrole-2-yl-methyleneamine) ligand yielded three complexes with different coordination geometries. X-ray crystal structural analysis reveals that in the nickel(II) complex each nickel is five-coordinate, distorted trigonal bipyramid. In the copper(II) complex, each copper is four-coordinate, between square planar and tetrahedral. In the zinc(II) complex, each zinc is four-coordinate with a distorted tetrahedral geometry and the molar ratio of the zinc and ligand is 1 : 2.     

Nickel(II) and cobalt(II) complexes of methyl(2-aminocyclopentene-1-dithiocarboxy)-S-acetate (ACDASAMe)

Nickel(II) and cobalt(II) bis-chelates of methyl(2-aminocyclopentene-1-dithiocarboxy)-S-acetate (ACDASAMe) were synthesized and characterized by spectroscopic methods and in the case of the nickel complex, X-ray single-crystal diffraction. The ligand exhibits the (N, S) coordination mode on interacting with the metal centers. The X-ray structure of the nickel(II) complex reveals a NiN₂S₂ distorted square planar coordination geometry with the ligands showing a cis configuration. There is no interaction between the –CH₂COOMe moieties of the ligand and the metal center, however intermolecular hydrogen bonds through the carbonyl group leads to the building of dimeric associations.     

Self‐Assembly,Spectroscopic and Electrochemical Studies of Nickel(II)‐4,8‐Diazaundecanediamide Complex

The self‐assembly of NiCl₂·6H₂O with a diaminodiamide ligand 4,8‐diazaundecanediamide (L‐2,3,2) gave a [Ni(C₉H₂₀N₄O₂)(Cl)(H₂O)] Cl·2H₂O ( 1 ). The structure of 1 was characterized by single‐crystal X‐ray diffraction analysis. Structural data for 1 indicate that the Ni(II) is coordinated to two tertiary N atoms, two O atoms, one water and one chloride in a distorted octahedral geometry. Crystal data for 1: orthorhombic, space group P 21nb, a = 9.5796(3) Å, b = 12.3463(4) Å, c = 14.6305(5) Å, Z = 4. Through NH···Cl–Ni (H···Cl 2.42 Å, N···Cl 3.24 Å, NH···Cl 158°) and OH···Cl–Ni contacts (H···Cl 2.36 Å, O···Cl 3.08 Å, OH···Cl 143°), each cationic moiety [Ni(C₉H₂₀N₄O₂) (Cl)(H₂O)]⁺ in 1 is linked to neighboring ones, producing a charged hydrogen‐bonded 1D chainlike structure. Thermogrametric analysis of compound 1 is consistent with the crystallographic observations. The electronic absorption spectrum of Ni(L‐2,3,2)²⁺ in aqueous solution shows four absorption bands, which are assigned to the ³A_2g → ³T_2g, ³T_2g → ¹Eg, ³T_2g → ³T_1g, and ³A_2g → ³T_1g transitions of triplet‐ground state, distorted octahedral nickel(II) complex. The cyclic volammetric measurement shows that Ni²⁺ is more easily reduced than Ni(L‐2,3,2)²⁺ in aqueous solution.     

Synthesis and Characterization of Metal Complexes of a New Unsymmetrical Tridentate NNS Schiff Base Ligand: X‐ray Crystal Structure Determination of Nickel(II) Complex

A new unsymmetrical tridentate NNS Schiff base ligand, 2‐(2‐nitrophenylthio)‐N‐((pyridine‐2‐yl)methylene)benzenamine (L), and its Mn(II ), Ni(II ), Cu(II ), and Zn(II ) complexes were synthesized. These compounds were characterized by different physicochemical and spectroscopic techniques. The molecular structure of [NiL₂ ](ClO₄ )₂ was determined by single‐crystal X‐ray diffraction. In this complex, two ligands coordinate through azomethine‐N, pyridine‐N, and thioether‐S, forming a mononuclear 6‐coordinate distorted octahedral geometry about a nickel.     

Copper(II), Cobalt(II), and Nickel(II) Complexes of two Novel Pyridine‐derived Macrocyclic Ligands bearing o‐ and pNitrobenzyl Pendant Groups

The pendant‐armed ligands L¹ and L² were synthesized by N‐alkylation of the four secondary amine groups of the macrocyclic precursor L using o‐nitrobenzylbromide (L¹) and p‐nitrobenzylbromide (L²). Nitrates and perchlorates of Cu^II, Ni^II and Co^II were used to synthesize the metal complexes of both ligands and the complexes were characterized by microanalysis, MS‐FAB, conductivity measurements, IR and UV‐Vis spectroscopy and magnetic studies. The crystal structures of L¹, [CuL¹](ClO₄)₂·CH₃CN·H₂O, [CuL²](ClO₄)₂·6CH₃CN, [CuL²][Cu(NO₃)₄]·5CH₃CN·0.5CH₃OH and [NiL²](ClO₄)₂·3CH₃CN·H₂O were determined by single crystal X‐ray crystallography. These structural analysis reveal the free ligand L¹, three mononuclear endomacrocyclic complexes {[CuL¹](ClO₄)₂·CH₃CN·H₂O, [CuL²](ClO₄)₂·6CH₃CN and [NiL²](ClO₄)₂·3CH₃CN·H₂O} and one binuclear complex {[CuL²][Cu(NO₃)₄]·5CH₃CN·0.5CH₃OH} in which one of the metals is in the macrocyclic framework and the other metal is outside the ligand cavity and coordinated to four nitrate ions.     

Synthesis, Crystal Structure and Thermal Stability of (Diacetylacetone)(diimidazole)Nickel(II) Complex

1 INTRODUCTION Acetylacetone is well known as the intermediate product of organic synthesis reaction, which can be used as annexing agent in gasoline, lubricant and desiccant in paint. Also it has been found to possess fungicidal and insecticidal activi…     

Perturbations of an Acetone‐Based Briggs–Rauscher System by α‐Tocopherol (Vitamin E)

The malonic acid (MA)‐based oscillating Briggs–Rauscher reaction (BR) in batch mode has been shown to be sensitive to various hydrophilic polyphenol antioxidants. Several of these have been shown to cause cessation of oscillations for a period of time before a restart occurs. The length of time before oscillations restart is related to the type of antioxidant and its concentration. Procedures have been devised to use this method as a tool for measuring antioxidant activity from pure compounds and from extracts of natural sources. The antioxidant activity has been related to the reaction of the antioxidants with HOO^. radicals present in the oscillating system. Vitamin E (α‐tocopherol), a typical highly lipophilic antioxidant containing an phenolic OH group, is soluble in acetone that also is a suitable substrate for the BR reaction. Perturbations of a highly concentrated acetone‐based BR oscillator by acetonic solutions of vitamin E were studied. The inhibitory effects were found similar to those provoked by hydrophilic polyphenols in the MA‐based oscillator, but to obtain reasonable inhibition times, the concentration of vitamin E must be at the mM level instead μM . However, there is a region of concentrations where there is a nearly linear relation between concentration and inhibition time. A comparison with a hydrophilic diphenol (2,6‐dihydroxybenzoic acid) in the acetone‐based oscillator showed that the inhibitory reaction is much slower in this system than in the MA one. We were able to model the perturbations by vitamin E assuming its reaction with HOO^. radicals by using the FCA mechanism previously reported with some little modifications.     

Synthesis and Structure of a Macrocyclic Dinickel Complex Incorporating a Hypercoordinated Sulfenium(II) Cation

The synthesis and structure of a macrocyclic dinickel complex incorporating a hypercoordinated sulfenium(II) cation are reported. The novel complex [Ni₂L³(Cl)]²⁺ was obtained from a reaction of the per‐hydroxyethylated N₆S₂ macrocycle H₂L² with NiCl₂(H₂O)₆ in the presence of air, and isolated as its ClO₄ or BPh₄ salt. The structure reveals a three‐coordinate sulfenium cation that is stabilized by two intramolecularly coordinating amino groups. The N–S bonds are 2.087(7) Å and 2.105(6) Å and the N–S–N bond angle is 168.2(2)°. The bonding is best described by a N,N‐chelated sulfur(II) atom (3c–4e bond) bearing two lone pairs and a formal charge of +1.     

The Effect of Sodium Dodecylbenzenesulfonate (SDBS) Micelles on a BelousovZhabotinsky Oscillating System Catalyzed with a Tetraazamacrocyclic Copper(II) Complex

This article deals with the influence of micelles of the anionic surfactant sodium dodecyl benzene sulfonate (SDBS) on the Belousov? Zhabotinsky (B? Z) oscillating reaction catalyzed by a tetraazamacrocyclic copper(II) complex [CuL](ClO₄)₂, an enzyme‐like catalyst (L=5,7,7,12,14,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradeca‐4,11‐diene). Unlike the classical B? Z oscillator in which malonic acid is usually used as a substrate, malic acid (an intermediate in the Krebs cycle) is involved in this oscillating system. Experiments reveal that formation of the SDBS micelles markedly affects the behavior of the oscillating reaction. It is found that there is a linear relationship between the change in the oscillation amplitude (ΔA) and the concentration of SDBS, whereas the change in the oscillation period (ΔT) is linearly proportional to the SDBS concentration. The most likely mechanism that involves the formation of the SDBS micelles and the effects of the micelles on the oscillating chemical system can be rationalized by assuming that the SDBS micelles are so negatively charged that they attract more [CuL]³⁺ than [CuL]²⁺. This hypothesis was confirmed by UV/VIS spectrophotometric measurements of a constant concentration of [CuL](ClO₄)₂ in different concentrations of SDBS; as the SDBS concentration increased, the absorbance of [CuL](ClO₄)₂ increased, while the maximum absorption wavelength for [CuL](ClO₄)₂ remained at 502 nm.     

Synthesis and Characterization of New Macrocyclic Cu（Ⅱ） Complexes from Various Diamines, Copper（Ⅱ） Nitrate and 1,4-Bis（2-formylphenoxy）butane

Six new macrocyclic complexes were synthesized by a template reaction of 1,4-bis（2-formylphenoxy）butane with diamines and Cu（NO3）2·3H2O and their structures were proposed on the basis of elemental analysis, FT-IR, UV-Vis, magnetic susceptibility measurements, molar conductivity measurements and mass spectra. The metal to ligand molar ratios of the Cu（Ⅱ） complexes were found to be 1 ： 1. The Cu（Ⅱ） complexes are 1 ： 2 electrolytes as shown by their molar conductivities （∧m） in DMF at 10^-3 mol·L^-1. Due to the existence of free ions the Cu（Ⅱ） complexes are electrically conductive. Their configurations were proposed to be probably distorted octahedral.