N-chlorophthalimide as a new oxidant for direct titrations in aqueous acetic acid medium

A stable new oxidimetric titrant, N-chlorophthalimide in anhydrous acetic acid, is proposed for direct titrations of a variety of simple and complex reductants such as As(III), Sb(III), Fe(II), ferrocyanide, iodide, ascorbic acid, hydroquinone, hydrazine, phenylhydrazine, benzhydrazide, isonicotinic acid hydrazide, semicarbazide, thiourea, aniline, phenol, oxine and its metal complexes, and anthranilic acid and its metal complexes.     

Infrared spectra of metal anthranilates

The infrared spectra of the sodium salts and the Mn(II), Co(II), Ni(II), Cu(II) and Zn(Il) chelates of anthranilic acid and 5-methyl-, 5-chloro-, 5-bromo-and 5-iodo-anthranilic acid are discussed. ¹⁵N-Labelling of sodium anthranilate and the complexes of anthranilic acid provides assignments of the ligand vibrations involving the amino group. The metal-ligand stretching frequencies (vM-N and vM-O) are assigned by observing the effects on the spectra caused by ¹⁵N-labelling, metal ion substitution and ligand substitution. The vCu-O bands are split by tetragonal distortion in the Cu(II) complex which involves elongation of the axial Cu~O bonds. The metal ion dependence of vM-N and vM-O parallels the Irving-Williams stability sequence. The ligand substituents shift vM-O in accordance with their inductive effects while vM-N exhibits a substituent dependence which is roughly the opposite of that shown by vM-O.     

The thermal behaviour of some Co(II) complex combinations with schiff bases

In order to evidence the ligand influence on the thermal stability for Co(II) complex combinations, we have synthesized five complex combinations of this metal with Schiff bases obtained by condensation of ethylenediamine with acetylacetone and benzoylacetone; phenylenediamine with benzoylacetone and also anthranilic acid with benzaldehyde. This revised version was published online in July 2006 with corrections to the Cover Date.     

Mononuclear and homobinuclear cobalt(II), nickel(II) and copper(II) complexes with mono and bis-azocompounds derived from 2,7-dihydroxynaphthalene and anthranilic acid or o-aminophenol

Two new series of mononuclear and homobinuclear Co(II), Ni(II) and Cu(II) complexes with mono- and bis-azo compounds derived from 2,7-dihydroxynaphthalene and anthranilic acid or o-aminophenol are prepared and characterized by elemental and thermal analyses, conductance, IR, electronic, ESR spectra and magnetic moment measurements. The ligand field splitting parameters and Racah constant are calculated. The spectral and magnetic results obtained are utilized to determine the geometries around the metal(II) ion. The geometry of the complex formed depends on the structure of the ligand and the type of metal(II) ion. The mode of bonding of the ligand with the metal ions is deduced from IR spectra.     

Modification of carbon nanofibres for the immobilization of metal complexes: a case study with rhodium and anthranilic acid

The immobilisation of the rhodium/anthranilic acid complex onto fishbone carbon nanofibres (CNFs) was executed by means of the following steps: 1) surface oxidation of the fibres, 2) conversion of the oxygen-containing surface groups into acid chloride groups, 3) attachment of anthranilic acid and 4) complexation of rhodium by the attached anthranilic acid. The immobilisation process was followed and the resulting surface species were characterised by IR, X-ray absorption fine structure (XAFS) and X-ray photoelectron spectroscopy (XPS), and by molecular modelling. Anthranilic acid bonds to the CNFs by an amide linkage to the carboxyl groups that are present after surface oxidation of the fibres. The immobilised anthranilic acid coordinates to rhodium through the nitrogen atom and the carboxyl group. The assynthesised RhIII complex itself is not active in the liquid-phase hydrogenation of cyclohexene. Reduction with sodium borohydride yields small particles (d = 1.5-2 nm) of rhodium metal that are highly active. The results indicate that different activation procedures for the immobilised Rh/anthranilic acid system should be applied, such as reduction with a milder reducing agent or direct complexation of the rhodium in the RhI state.     

Radical scavenging and catalytic activity of metal-phenolic complexes

A series of metal-ligand complexes were prepared by the reaction of various metal ions, namely, Cu(II), Mn(II), or Fe(II) with phenolic derivatives of [catechol, chlorogenic acid (CGA), n-propyl gallate (nPG), 3-hydroxy anthranilic acid, resveratrol, and rutin] and characterized by UV-vis spectroscopy. The metal/ligand complexing ratio and complexation constants have been determined. The complexes were probed for their reactivity toward various free radicals (e aq-, CO2*-, and O2*-). Pulse radiolysis studies showed that the one-electron reduction of metal/phenol complexes by CO2*- radicals was metal-centered, and this was confirmed by the formation of an initial adduct with CO2*- radicals. Rate constants for the scavenging of superoxide anions with metal complexes ranged between 10(7)-10(9) dm3 mol(-1) s(-1) and those for the reaction of e aq- with the metal complexes were in the range of (1-5) x 10(9) dm3 mol(-1) s(-1), depending on the pH of the solution. Cyclic and differential pulse voltammetric studies showed that the reduction potential of the complexes are found to range between -0.022 to 0.45 V vs normal hydrogen electrode.     

Thermal decomposition kinetics and mechanism of Cu(II), Zn(II) and Cd(II) complexes derived from fluorenone anthranilic acid

Copper(II), zinc(II) and cadmium(II) complexes of the Schiff base, fluorenone anthranilic acid were prepared and characterized by elemental analysis, magnetic measurements, conductivity experiments and electronic and infrared spectral studies. The thermal decomposition kinetics and mechanism of these chelates was studied from TG data.     

Features of Cobalt(II) Complexes Formation with Pharmacophore-Modified Apple Pectin

Russian Journal of General Chemistry - Complexation of cobalt(II) chloride with apple pectin modified with organic pharmacophores (nicotinic, salicylic, 5-aminosalicylic, or anthranilic acid) has...     

Reactions of diarylamines with hexafluoroacetone

Diphenylamine reacts with hexafluoroacetone to give a mixture of products, of which 2-(1-hydroxy-1-trifluoromethyl-2,2,2-trifluoroethyl)diphenylamine (II) was isolated. N-Arylanthranilic acids modify the 1,1,1,3,3,3-hexafluoro-2-hydroxy-2-propyl group upon the reaction of its sodium salt with the hydrate of hexafluoroacetone (I) under mild conditions. This method gave 4-(1-hydroxy-1-trifluoromethyl-2,2,3-trifluoroethyl)-N-(2,3-xylyl)anthranilic acid from N-(2,3-xylyl)anthranilic acid in 93% yield.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 952–954, April, 1991.     

The determination of small quantities of metal ions using anthranilic acid

Metal ions which form insoluble anthranilates may, if present singly, be determined by dissolving the anthranilate in acid and titrating the liberated anthianilic acid with perchloratocerate. Or preferably the anthranilic acid may be determined absorptiometrically with N-(1-naphthyl) ethylenediamine hydrochloride after diazotisation. Under the conditions described quantities of the order of 1–5 micromoles of metal are conveniently determined by the volumetric method and one fifth of such amounts by absorptiometry. With the latter the use of larger Spekker cells would increase the sensitivity of the method.By making use of the insolubility of its complex in acetate buffers copper may be determined in the presence of other metals if these are not in excessive amounts. Various other determinations. are also possible.Attempts to use the fluorescence of the liberated anthranilic acid have indicated the method to be less satisfactory than absorptiometry.     

聚邻氨基苯甲酸-铜复合薄膜修饰电极的制备及其电化学性能

利用聚合物官能团对金属离子的配位作用,在电极表面原位制备了金属粒子。 首先在玻碳电极（GCE）表面电沉积聚邻氨基苯甲酸(PoABA),再化学吸附铜离子(Cu2+),用水合肼还原得到单质铜(Cu0)。 采用扫描电子显微镜和能谱分析表征了聚邻氨基苯甲酸 铜(PoABA-Cu0)复合薄膜的表面形貌和元素构成,研究了PoABA-Cu0修饰电极的电化学性能,并以其检测了过氧化氢（H2O2）。 结果表明,电极表面被修饰上了一层PoABA-Cu0复合薄膜;制备的修饰电极对H2O2具有良好的电催化性能,在邻氨基苯甲酸的聚合圈数为10、Cu2+的吸附时间为10 min、工作电压为-0.3 V时,该修饰电极对H2O2表现出了最佳的检测性能,其线性浓度范围为5.0×10-5～1.0×10-2 mol/L,灵敏度为96.3 μA·L/(mmol·cm),检测限为5.0×10-5 mol/L,且具有较好的稳定性。     

Magnetic and electronic characterization of 2:1 copper(II) complexes of a series of aminocarboxylic acids

Copper(II) complexes with L-(—)-proline, pipecolinic acid, picolinic acid, anthranilic acid, 4-chloranthranilic acid, 3,5,-dichloroanthranilic acid, 4-nitroanthranilic acid, N-phenyl-anthranilic acid, and flufenamic acid anions were prepared and characterized. The copper complexes of the anions of proline, pipecolinic acid, and picolinic acid are soluble in polar solvents and display frozen solution EPR spectra with axial resonance parameters. The copper complexes of the ring-substituted anthranilates are highly insoluble or only slightly soluble in a few solvents. The EPR spectra of the copper-doped zinc(II) analogues of these complexes display various degrees of rhombicity in their EPR parameters. The N-substituted anthranilates form insoluble complexes in aqueous solution which readily dissolve in organic solvents and undergo dimerization.     

Palladium-catalyzed mono-N-allylation of unprotected anthranilic acids with allylic alcohols in aqueous media

Palladium-catalyzed N-allylation of anthranilic acids 1a-j with allyl alcohol 2a in the presence of Pd(OAc)(2), sodium diphenylphosphinobenzene-3-sulfonate (TPPMS) in THF-H(2)O at room temperature gave only mono-N-allylated anthranilic acids 3a-j in good yields (70-98%). The reactions of 4-bromoanthranilic acid 1i with 2-methyl-3-buten-2-ol 2b showed complete chemoselectivity in N-allylation (neutral conditions) and C-vinylation (basic conditions). In our catalytic system, the keys to success are use of an unprotected anthranilic acid as a starting material and the presence of water in the reaction medium. The carboxyl group of anthranilic acid and water may play important roles for the smooth generation of the π-allyl palladium species by activation of the hydroxyl group of the allylic alcohol.     

Direct spectrophotometry of silver in a non-aqueous medium

Silver in the range 0.01–10 p.p.m. is extracted from aqueous solution containing anthranilic acid diacetic acid into methyl isobutyl ketone as silver di-n-butylammonium salicylate without interference from 10-fold amounts of Mg, Ca, Zn, Pb, Al, Cu(II), Ni Co(II), Mn(II), Fe(III), Bi or any compatible common anion. Hg(II) is co-extracted slightly but can be retained in the aqueous phase with EDTA. Spectrophotometric determination of the extracted silver is done with pyrogallol red at 390 mμ in 4-cm cuvettes. The colour system is stable and reproducible. No special purification of reagents is necessary even for the lowest concentrations of silver.     

Adsorption behaviour of metal ions on hydroximate resins

Some new chelating ion-exchange resins containing a hydroxamic acid moiety attached to a divinylbenzene styrene (DVBS) copolymer, i.e. glycine hydroximate in DVBS (GH-DVBS). anthranilic acid hydroximate in DVBS (AAHDVBS), malonic acid dihydroximate in DVBS (MAH-DVBS) and iminodiacetic acid dihydroximate in DVBS (IDAAH-DVBS). have been synthesized and their various physicochemical characteristics studied. The degree of retention of metal ions by the resins at equilibrium has been determined in terms of the molar distribution coefficient (k(d)). In general, the resins having a dihydroximate moiety are found to be more efficient compared to monohydroximate resins. However, it is of interest to note that the monohydroximate derivative of amino acid (GH-DVBS) showed better metal retention capability than the dihydroximate of carboxylic acid (MAH-DVBS). The selectivity of the resins for transition and highly charged metal ions is quite high compared to that for alkaline earth metals. All the synthesized resins can be utilized for the separation of a mixture of metal ions because the differences in the distribution coefficient values are large enough to permit good separations on columns. However, the GH-DVBS resin was tried for the separation of copper cobalt and copper nickel mixtures at pH 5.5 using the column mode of operation.     

Analytical Separation of Copper(II), Cobalt(II) and Nickel(II) Using Polymer Bound Anthrantic Acid

Abstract

The preferential complexing tendency of different nietal ions towards chelating agents anchored on a polymer has been used for separation of transition metals. the anthranilic acid group was anchored on the polymeric cellulose back-bone by successive coupling with trifunctional reagent cyanuric chloride, in diozane medium, at pH 7 and 9–10, respectively. This polymer bound chelating agent was used to separate copper(II), nickel(II) and cobalt(II) in the concentration range 1.0–0.1 mmol/L. the separation of a mixture of two components was quantitative using column chromatography.     

N-[3-nitro(amino)coumarin-4-yl]anthranilic acid amides. Synthesis of 6,7,8,13-tetrahydro[1]benzopyrano[4,3-b][1,4] benzodiazepine-6,8-dione

The reaction of 3-nitro-4-chlorocoumarin with anthranilic acid was used to synthesize N-(3-nitro-4-coumarinyl)-anthranilic acid, from which, through the acid chloride, we obtained a number of amides, which were reduced to N-(3-amino-4-coumarinyl)anthranilic acid amides The latter are cyclized under the influence of hydrochloric acid to 6,7,8,13-tetrahydro[1]benzopyrano-[4,3-b][1, 4]benzodiazepine-6,8-dione, which was also obtained from N-(3-amino-4-coumarinyl)anthranilic acid by its thermolysis or treatment with hydrochloric acid.See [1] for our preliminary communication.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1208–1212, September, 1989.     

Physicochemical Studies and Thermal Decomposition Kinetics of Co(II), Ni(II), Cu(II) and Zn(II) Complexes of Citronellal Anthranilic Acid

Cobalt(II), nickel(II), copper(II) and zinc(II) complexes of two new Schiff-bases, citronellal anthranilic acid and citronellal-5-bromoanthranilic acid have been synthesized. On the basis of spectral, magnetic and thermal data, octahedral structure was assigned to all complexes [ML₂(H₂O)₂]. Thermal decomposition of these complexes was studied by TG. Kinetic parameters, viz activation energy, E, pre-exponential factor, A, and order of reaction, n, were calculated from the TG curves using mechanistic and non-mechanistic integral equations. This revised version was published online in July 2006 with corrections to the Cover Date.     

An ion-association system for the selective extraction of mugram amounts of silver from aqueous solution

Silver can be extracted from aqueous solution into hexone as the ion-association system formed between its di-n-butylamine complex and stearic acid or salicylic acid. In the presence of an auxiliary complexing agent, anthranilic acid diacetic acid, the latter system is highly selective since only mercury(II) interferes. The procedure is sensitive and extracts silver over the range 5 mg–5μg (0.05 p.p.m.). No compatible common anion interferes. The extraction is 96–98% complete in one pass.     

Cyclopolycondensations. VII. Preparation of aromatic poly(ureido acids) by the low-temperature solution polymerization and cyclodehydration to fully aromatic polyquinazolinediones

Fully aromatic polyquinazolinediones (IV) of high molecular weight were obtained by thermal cyclodehydration of aromatic poly(uredio acids) (III) prepared by the polyaddition reaction of 4,4′-diaminobiphenyl-3,3′-dicarboxylic acid (I) with aromatic diisocyanates (II). From the kinetic study of reactions of model systems (anthranilic acid with phenyl isocyanate) in the presence of a variety of basic catalysts, it was established that tertiary amines had the highest catalytic activity for the formation of ureido linkage. The optimum polymerization conditions were determined by the study of reaction variables such as monomer concentration, polymerization temperature, monomer ratio, and catalyst concentration. The effect of polarity and purity of organic solvents and reactants was also studied.