Schiff碱配合物的研究——Ⅸ.表面Schiff碱配合物对H2O2分解的催化作用

制备了两种表面Schiff碱及其Cu²⁺、Co²⁺、Ni²⁺、Zn²⁺配合物,考察了它们对H₂O₂分解的催化性能,其活性顺序为:Co²⁺>Cu²⁺>Ni²⁺>Zn²⁺,且与金属离子氧化还原电位有关。溶液的pH值增加有利于催化反应,有机配体的加入则对反应有所抑制。     

Graft copolymerization to cellulose by the metallic ion–hydrogen peroxide initiator system

The decomposition of hydrogen peroxide and the graft copolymerization of methyl methacrylate has been investigated by use of cellulose samples adsorbing various metallicions. Metallic ions generally accelerate the decomposition of hydrogen peroxide, increase the number of grafts, and lower the average molecular weight. However their effects are much influenced by the range of pH values. It is clear that the amount of grafts formed is not necessarily proportional to the amount of decomposed hydrogen peroxide and is dependent upon a function peculiar to each metallic ion. The effective metallic ions in the neutral system were Cu²⁺, Ag⁺, Fe²⁺, Co²⁺, Cr³⁺, and Zn²⁺. The effects of Ce³⁺, Mg²⁺, Hg³⁺, Cd²⁺, Ni²⁺ and Mn²⁺ were either negligible or negative. Comparative studies on various conditions confirmed that Fe²⁺ in the neutral system gives graft copolymer having a minimum average molecular weight and the greatest number of grafts.     

Chelation ion-exchange properties of salicylic acid-urea-formaldehyde copolymers

Chelation ion-exchange properties of copolymers prepared from salicylic acid, urea and formaldehyde by condensation in presence of acid catalyst were studied for Cu²⁺, Fe³⁺, UO²⁺, Mn²⁺,Zn²⁺ and Co²⁺ ions. A batch equilibration method was adopted to study the selectivity of metal ion uptake. This method involved the measurement of distribution of a given metal between the copolymer sample and a solution containing the metal ions. The study was carried out over a wide pH range and in media of various ionic strengths. The copolymer showed a higher selectivity for UO₂ ²⁺, Cu²⁺ and Fe³⁺ ions than Mn²⁺, Co²⁺ and Zn²⁺ ions.     

Study on the synthesis of novel fluorescent macrocyclic sensors and their sensitive properties for Cu2+ and Fe3+ in aqueous solution

In this work, we synthesised and characterised three novel fluorescence macrocyclic sensors containing optically active dansyl groups. The studies for the interaction of the synthesised compounds with various mental ions (Li⁺, Na⁺, K⁺, Ag⁺, Mg²⁺, Ca²⁺, Ba²⁺, Pb²⁺, Zn²⁺, Co²⁺, Cd²⁺, Hg²⁺, Ni²⁺, Cu²⁺, Mn²⁺, Cr³⁺, Al³⁺, Fe³⁺) were performed by fluorescence titration, Job’s plot, ESI-MS and DFT calculations. The results showed that the sensors 1a–1c displayed selective recognition for Cu²⁺ and Fe³⁺ ions and formed stoichiometry 1:1 complex through PET mechanism in DMSO/H₂O solution (1:1, v/v, pH 7.4 of HEPES). The binding constant (K) and detection limit were calculated.     

1-(d-Glucopyranosyl-2′-deoxy-2′-iminomethyl)-2-hydroxynaphthalene as chemo-sensor for Fe in aqueous HEPES buffer based on colour changes observable with the naked eye

A new glucose-based C2-derivatized colorimetric chemo-sensor (L₁) has been synthesized by a one-step condensation of glucosamine and 2-hydroxy-1-naphthaldehyde for the recognition of transition metal ions. Among the eleven metal ions studied, viz., Mg²⁺, Ca²⁺, Mn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺ and Hg²⁺, L₁ results in visual colour change only in the presence of Fe²⁺, Fe³⁺and Cu²⁺ in methanol. However, in an aqueous HEPES buffer (pH 7.2) it is only the Fe³⁺ that gives a distinct visual colour change even in the presence of other metal ions, up to a concentration of 280 ppb. The changes have been explained based on the complex formed, and the composition has been determined to be 2:1 between L₁ and Fe³⁺ based on Job’s plot as well as ESI MS. The structure of the proposed complex has been derived based on HF/6-31G calculations.     

Vibrational and scanning electron microscopy study of the mordenite modified by Mn, Co, Ni, Cu, Zn and Cd

The mordenite samples loaded with divalent nitrates of Mn, Co, Ni, Cu, Zn and Cd were investigated using FTIR and scanning electron microscopy (SEM) methods. It was found from FTIR spectra that in 3000-4000 cm⁻¹ region of mordenite samples with similar water concentration ions, Mn²⁺, Co²⁺, Cu²⁺, and Zn²⁺ tend to break hydrogen bonds formed between water molecules and zeolite framework, whereas Ni²⁺ and Cd²⁺ accommodate to hydrogen bonds. From SEM results it was concluded, that ions Mn²⁺, Co²⁺, Zn²⁺ form innersphere complexes with oxygens from Brönsted acid sites, whereas Ni²⁺ and Cd²⁺ associate with Brönsted acid sites without exchange of protons.     

Chemiluminescence of CdTe quantum dots using K3Fe(CN)6 as oxidant and its capping ligand-dependent effect

Water-soluble CdTe quantum dots (QDs) capped with three different thioalkyl acids (mercaptoacetic acid, cysteine and glutathione) were synthesized in aqueous solution. In basic media, K₃Fe(CN)₆ could directly oxidize the water-soluble CdTe QDs to produce strong CL emission. It was found that the CL intensity depended on the capping ligand and size of CdTe QDs. CL spectra and fluorescence spectra of the system were measured to investigate the CL reaction mechanism. Moreover, the effects of 17 metal ions on the CL system were carefully investigated. Ca²⁺, Co²⁺, Mn²⁺, Hg²⁺, Mg²⁺, Cu²⁺, Ni²⁺, Cr³⁺ and Fe³⁺ could markedly inhibit the CL signal of the K₃Fe(CN)₆–CdTe QDs system, which makes it applicable for the detection of such ions. This work is of importance for gaining a better understanding of the unique optical and physical chemistry properties of QDs, and it is also helpful to find more practical applications of QDs.     

Synthesis and characterization of 2, 4-dihydroxy-benzaldehydeoxime-formaldehyde polymers and their application as ion-exchangers

Polymers were prepared by the condensation of 2, 4-dihydroxybenzaldehydeoxime (2, 4-DBO) and formaldehyde (F) in the presence of oxalic acid as catalyst with varying molar ratios of reacting monomers. Polymers were characterized by their IR spectra, elemental analyses, TGA and M_n as determined by vapour pressure osmometry as well as by non-aqueous conductometric titrations. Viscosity measurements of the solutions of polymer samples were carried out in dimethylformamide. Chelation ion-exchange properties have also been studied employing the batch equilibration method. This method involved the measurement of distribution of a given metal between the polymer sample and a solution containing metal ions. The study was carried out over a wide pH range and in media of various ionic strengths. The polymer showed a higher selectivity for UO ₂ ²⁺ and Fe³⁺ ions than for Cu²⁺, Ni²⁺, Co²⁺ and Mn²⁺ ions.     

Die gravimetrische Halbmikro-Bestimmung des Palladiums mit Violursäure

Zusammenfassung Die Fällung des Palladiums als Violurat eignet sich zur Bestimmung des als Chlorid vorliegenden Metalls neben Pt⁴⁺, Co²⁺, Ni²⁺, Fe³⁺, Cu²⁺, Mn²⁺, Zn²⁺, Ca²⁺, den Alkalien und neben größeren Mengen von Pb²⁺-Ionen.

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Summary The precipitation of palladium as violurate is suitable for the determination of the metal present as chloride even in the presence of: Pt⁴⁺, Co²⁺, Ni²⁺, Fe³⁺, Cu²⁺, Mn²⁺, Zn²⁺, Ca²⁺, the alkalis and also considerable amounts of Pb²⁺ ions.

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Résumé Le précipité de violurate de palladium convient pour le dosage de cet élément préexistant sous forme de chlorure, en présence de Pt⁴⁺, Co²⁺, Ni²⁺, Fe³⁺, Cu²⁺, Mn²⁺, Zn²⁺, Ca²⁺, des métaux alcalins et de grandes quantités d'ions Pb²⁺.

     

Cleavage of Qinghaosu (Artemisinin) Induced by Non‐Iron Transition‐Metal Ions in the Presence of Excess Cysteine

In the presence of an excess of cysteine, a catalytic amount of a non‐iron transition‐metal ion (Co²⁺, Cu²⁺, Ni²⁺, Ti⁴⁺, and Mn²⁺) may also induce cleavage of qinghaosu (artemisinin; 1 ) to give those end products previously reported for Fe²⁺‐mediated degradation.     

Studying the photophysical properties of a polymerizable 1,8‐naphthalimide dye and its copolymer with styrene as potential fluorescent sensors for metal cations

The photophysical characteristics of a polymerizable 1,8‐naphthalimide dye and its copolymer with styrene have been investigated. The functional properties of both low and high molecular weight fluorophores in the presence of different metal cations have been discussed with regard to their potential application as fluorosensors for the metal cations and protons. In acetonitrile solution the monomeric 1,8‐naphthalimide enhances its fluorescence emission in the presence of metal cations (Zn²⁺, Fe³⁺, Co²⁺, Pb²⁺, Cu²⁺, Ni²⁺, and Mn²⁺). In aqueous media the poly(St‐co‐MD) exhibits a selective response to Fe³⁺ cations. The monomeric and polymeric fluorophores also exhibit a considerable increase in their fluorescence intensity at acidic pH values (pH < 6) which suggest that they could be used as ON–OFF probes in analytical devices for signaling the presence of protons. Copyright © 2008 John Wiley & Sons, Ltd.     

Thermodynamic investigation of the binary and ternary complexes involving 1-aminocyclopropane carboxylic acid with reference to plant hormone

Complex formation equilibria of 1-aminocyclopropane carboxylic acid (ACC) and 3,3-bis(1-methylimidazol-2-yl) propionic acid (BIMP) with metal ions Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺, Mn²⁺ and Fe²⁺ were investigated. ACC forms 1:1 and 1:2 complexes in addition to the hydrolysed form of the 1:1 complex, except in the case of Mn²⁺ and Fe²⁺, where the hydrolysed complex is not formed. BIMP forms 1:1 and 1:2 complexes in addition to the hydrolsed form of the 1:1 complex in the case of Mn²⁺ and Cu²⁺, however the hydrolysed complex is not detected for Ni²⁺, Co²⁺, Zn²⁺ and Fe²⁺. The concentration distribution diagrams of the complexes were determined. The Fe²⁺-complex with BIMP is exothermic and the thermodynamic parameters were calculated. The effect of organic solvent on the acid dissociation constants of 1-aminocyclopropane carboxylic acid (ACC) and 3,3-bis(1-methylimidazol-2-yl) propionic acid (BIMP) and the formation constants of Fe²⁺ complexes were investigated. Fe²⁺ forms a mixed-ligand complex with ACC and BIMP with stoichiometric coefficients 1:1:1. The formation constant was determined. The ternary complex is enhanced by back donation from the negatively charged 1-aminocyclopropane carboxylate to the π-system of BIMP. From the concentration distribution diagram, the ternary complex prevails in the physiological pH range.      

Complexes of hydroxamic acid of carboxyethyl dextran with ions of some <Emphasis Type="Italic">d</Emphasis>-elements

Complexing capacity of carboxyethyldextranhydroxamic acid with respect to the metal cations Fe³⁺, Cu²⁺, Ni²⁺, Co²⁺, and Mn²⁺ was studied. A procedure for synthesis of the complexes being formed was suggested and the compounds obtained were analyzed by IR and electronic absorption spectroscopies.     

Synthesis and characterization of graphene oxide‐based hybrid ligand and its metal complexes: Highly efficient sensor and catalytic properties

A new graphene oxide‐based hybrid material (HL) and its Co(II), Cu(II) and Ni(II) metal complexes were prepared. Firstly, graphene oxide and (3‐aminopropyl)trimethoxysilane were reacted to give graphene oxide–3‐(aminopropyl)trimethoxysilane (GO‐APTMS) hybrid material. After that, hybrid material HL was synthesized from the reaction of GO‐APTMS and 2,6‐diformyl‐4‐methylphenol. Finally, Co(II), Cu(II) and Ni(II) complexes of HL were obtained. All the materials were characterized using various techniques. The chemosensor properties of HL were investigated against Na⁺, K⁺, Cd²⁺, Co²⁺, Cu²⁺, Hg²⁺, Ni²⁺, Zn²⁺, Al³⁺, Cr³⁺, Fe³⁺ and Mn³⁺ ions and it was found that HL has selective chemosensing to Fe³⁺ ion. All the graphene oxide‐supported complexes were used as heterogeneous catalysts in the oxidation of 2‐methylnaphthalene (2MN) to 2‐methyl‐1,4‐naphthoquinone (vitamin K₃, menadione) in the presence of hydrogen peroxide, acetic acid and sulfuric acid. The Cu(II) complex showed good catalytic properties compared to the literature. The selectivity of 2MN to vitamin K₃ was 60.23% with 99.75% conversion using the Cu(II) complex.     

Extraction-photometric determination of vanadium(V) with N-hydroxy-N-m-tolyl-N′-(2-methyl-5-chloro)phenyl-p-toluamidine hydrochloride in the presence of acetic,monochloroacetic, and phenylacetic acids

N-Hydroxy-N-m-tolyl-N′-(2-methyl-5-chloro)phenyl-p-toluamidine hydrochloride (HTMCPTH), a monobasic and bidentate chelating agent which reacts with vanadium(V) in carboxylic acid media to develop a blue-violet complex, has been employed as a highly selective reagent for extraction and direct photometric determination of the metal. Solvent extraction experiments indicate that from aqueous acetic acid (1.0–10.0 M), monochloroacetic acid (0.1–10.0 M), and phenylacetic acid (at pH 0.5–6.0) vanadium(V) is quantitatively extracted into chloroform. Almost all common ions including Fe³⁺, Cu²⁺, Ni²⁺, Co²⁺, Mn²⁺, Cr³⁺, Ti⁴⁺, Zr⁴⁺, and Mo⁶⁺ do not interfere with the proposed method. The procedure has been utilized for accurate determination of vanadium in standard steels.     

The spectrophotometric and titrimetric determination of gold with ferroin as reagent

A spectrophotometric and a photometric titration method in a two-phase system for the determination of gold with ferroin is reported. Both methods are rapid and reproducible with an accuracy of ±1%. In the spectrophotometric determination Co²⁺, Cu²⁺, Ni²⁺ , Fe³⁺, Zn²⁺, Mn²⁺ and Cr³⁺ do not interfere with the determination of gold and Pt⁴⁺, Pd²⁺, Hg²⁺, Ir⁴⁺ and Os⁴⁺ can be tolerated up to a ratio of 1:1. The titrations can also be carried out in the presence of a number of diverse ions, e.g. Ni²⁺, Cu²⁺, Co²⁺, Fe³⁺, Zn²⁺, Cr³⁺, Mn²⁺, without interference; the platinum metals and Hg²⁺ cause interference but, by the use of the spectrophotometric procedure, this can be reduced.     

Photo-Physical Properties of a New Norfloxacin-Containing Polymer for Protons and Fe3+ Sensing

A novel norlfoxacin-containing fluorescent polymer was synthesized via copolymerization of two derivatives of norfloxacin and methylmetacrylate (MMA). It could emit blue fluorescence in both the solution and film states. Fluorescence characteristics of the polymer as a function of pH were investigated in aqueous solution. The polymer solution showed weaker fluorescence between pH 5-9. When the pH of the solution was higher than 9 or lower than 5, stronger fluorescence could be seen. Responses of metal cations (Mn^{2 +}, Fe^{3 +}, Co^{2 +}, Ni^{2 +}, Cu^{2 +} and Zn^{2 +}) to the fluorescence intensity of this polymer were obtained that only Fe^{3 +} could quench efficiently the fluorescence intensity of the polymer in solution and film state. The results suggested the possibility that this newly synthesized compound might work as a polymeric sensor responding to water polluted by protons and Fe^{3 +}.     

Electrically induced fluorescence Fe sensing behavior of nanostructured Tiron doped polypyrrole

Nanostructured polypyrrole (PPy) film doped with Tiron was electrodeposited from aqueous solution on the surface of transparent electrode and used for sensitive, selective and rapid electrically controlled fluorescence detection of Fe³⁺ in aqueous media. The fluorescence intensity of PPy-Tiron film decreases linearly in the presence of Fe³⁺ by applying negative potential over a concentration range from 5.0 × 10⁻⁸ to 1.0 × 10⁻⁶ mol L⁻¹, with a relatively fast response time of less than 30 s at pH 7.4. The detection is not affected by the coexistence of other competitive metal ions such as Al³⁺, Ce³⁺, Tl³⁺, La³⁺, Bi³⁺, Cr²⁺, Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Pb²⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, Sr²⁺ and Ba²⁺. The proposed electro-fluorescence sensor has a potential application to the determination of Fe³⁺ in environmental and biological systems. The fluorescent thin film sensor was also used as a novel probe for Fe³⁺/Fe²⁺ speciation in aqueous solution.     

Synthesis of new benzimidazolium salts with tunable emission intensities and their application as fluorescent probes for Fe in pure aqueous media

A series of novel, water-soluble benzimidazolium salts with common ‘fluorophore–spacer–receptor’ PET design has been synthesized. Despite the common PET scaffold these benzimidazolium salts displayed diverse emission intensities in pure aqueous solutions. The observed emission intensities were found to be influenced by the functionalized alkyl side arms present on the benzimidazolium ring. These benzimidazolium salts were also found to act as selective sensors for Fe³⁺ ions over other metal ions like Na⁺, K⁺, Ca²⁺, Mg²⁺, Ba²⁺, Al³⁺, Cr³⁺, Co²⁺, Ni²⁺, Mn²⁺, Zn²⁺, Pb²⁺, Ag⁺, Cu²⁺ and Hg²⁺ in pure aqueous media.     

Tridentate benzimidazole ligand and its metal complexes: Synthesis,characterization, photo physical and sensor properties

A tridentate bisbenzimidazole-pyridine ligand (L-C⁵) with two pentyl side-units and its metal complexes with Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺ metal ions were synthesized and characterized. The structures of the ligand (L-C⁵) and its five coordinate [Mn(L-C⁵)Cl₂] were elucidated by single crystal X-ray diffraction studies. The absorption and photoluminescence properties of the compounds were studied in solution media. The ligand is highly fluorescent, and binding of the metal ions to the ligand has caused significant changes in the emission band (shift or quenching). Moreover, the effect of aggregation on UV–Vis. absorption and emission properties was examined in MeOH-water mixtures. The ligand was found to show aggregation-induced quenching in the MeOH-water mixture. The ligand was also screened for its colorimetric and fluorometric sensing ability of several metal ions [Na⁺, K⁺, Mg²⁺, Al³⁺, Ca²⁺, Mn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Hg²⁺, Pb²⁺]. The ligand showed selective sensing ability towards Zn²⁺, and the limit of detection was calculated as 3.09 × 10⁻⁷ m . The ligand also showed a distinguishable color change in the presence of Fe²⁺ under daylight.