Optical and chromaticity characteristics of palladium(II) complex with 1-nitroso-2-naphthol-3,6-disulfonic acid

Optimal conditions of complexation palladium(II) with 1-nitroso-naphthol-3,6-disulfonic acid were found by the spectrophotometric method (an optimum interval pH 1.2–3.8, a five-multiple surplus reagent). The analytical characteristics of a complex in an interval concentration of palladium(II) (0.94–8.59) × 10⁻⁵ M are determined, ɛ = (9.80 ± 0.02) × 10³ (n = 9, P = 0.95). The function and molar coefficient of chromaticity are determined. The most sensitive functions are G [(7.6 ± 0.1) × 10⁵] and Z [(5.6 ± 0.2) × 10⁵] (n = 5, P = 0.95).     

Optical and chromaticity characteristics of copper(II) complex with 1-nitroso-2-naphthol-3,6-disulfonic acid

Optimal conditions of complexation copper(II) with 1-nitroso-2-naphtol-3,6-disulfonic acid were found by the spectrophotometric method. The optimum pH interval for the formation of a complex is 6.5–7.9. A tenfold surplus of the reagent suffices for the quantitative formation of a complex. The chemical and analytical characteristics of a complex in an interval concentration of copper (1.26–6.39) × 10⁻⁵ M are determined. The molar coefficient of absorption of a complex is (1.21 ± 0.01) × 10⁴ (n = 5, P = 0.95). The function and molar coefficient of chromaticity are determined. The most sensitive functions are Z [(2.58 ± 0.04) × 10⁵] and G [(3.88 ± 0.06) × 10⁵] (n = 5, P = 0.95).     

Optical and colorimetric characteristics of a nickel(II) complex with 1-nitroso-2-naphthol-3,6-disulfonic acid

Optimal conditions for the complexation of nickel(II) with 1-nitroso-2-naphthol-3,6-disulfonic acid were found using the spectrophotometric method. The optimal pH interval for complexation was 7.2–8.8 with a fivefold excess of the reagent. The stoichiometric Me: R composition was 1: 2. The molar absorption coefficient and colorimetric characteristics of the complex were determined in the nickel(II) concentration range of (4.09–16.35) × 10⁻⁵ M. The molar absorption coefficient was (7.52 ± 0.05) × 10³ (n = 10, P = 0.95). The most sensitive chromaticity functions were B [(1.83 ± 0.04) × 10⁵] and G [(1.76 ± 0.05) × 10⁵] (n = 9, P = 0.95).     

Photometric determination of aqueous cobalt (II), nickel (II), copper (II) and iron (III) with 1-nitroso-2-naphthol-3,6-disulfonic acid disodium salt in gelatin films

Photometric determination of aqueous Co(II), Cu(II), Ni(II) and Fe(III) was performed using indicator films prepared by immobilization of 1-nitroso-2-naphthol-3,6-disulfonic acid disodium salt (NRS) into hardened photographic film. Immobilization was based on electrostatic interaction of reagent and metal complexes with the gelatin. The isoelectric point pH of hardened gelatin (4.46±0.04) was evaluated by viscometry. Co(II), Fe(III), Ni(II) form 1:3 complexes with NRS in gelatin at pH 2 and Cu(II) forms 1:2 complexes. Their log β′ values were: Co-6.7, Fe-8.6, Cu-8.0, and Ni-6.4. The absorption maxima were: 370nm for NRS, and 430nm, 470nm, 495nm and 720nm for complexes of Co(II), Ni(II), Cu(II) and Fe(III). An algorithm for their simultaneous determination using the indicator films was developed. The detection limits were: c_lim(Co²⁺) = 0.45×10⁻⁵ M, c_lim(Fe³⁺) = 0.50×10⁻⁵ M, c_lim(Cu²⁺) = 0.67×10⁻⁵ M, c_lim(Ni²⁺) = 0.75×10⁻⁵ M,; and their sum c_lim(ΣMn⁺) = 0.82×10⁻⁵ M.      

Optical and chromaticity parameters of transition metal complexes with 1-nitroso-2-naphthol-3,6-disulfonic acid in the presence of surfactants

Optimal conditions for the complexation of transition metal ions [Cu(II), Ni(II), Co(II, III), and Fe(II, III)] with 1-nitroso-2-naphthol-2,6-disulfonic acid have been determined by spectrophotometry in the presence of cationic (cetylpyridinium and cetyltrimethylammonium bromides) and nonionic (OP-10, neonol) surfactants. The introduction of nonionic surfactants does not influence the optical parameters of the system, while the introduction of cationic ones leads to hyperchromic and hypsochromic (for the system Fe(III)-NRS-surfactant) effects. The stoichiometric ratios determined by the method of isomolar series and treatment of the saturation curves of cationic surfactants at pH 4.0 are Me(II): R: surfactant = 1: 2: 4, Me(III): R: surfactant = 1: 3: 6. The molar absorption coefficients and chromaticity parameters of ternary complexes have been determined. A 2–5-fold increase in the molar absorption coefficients and chromaticity functions as compared to binary systems has been revealed.     

A selective and sensitive film for electrocatalysis of ascorbic acid based on polypyrrole doped with nitroso-R(1-nitroso-2-naphthol-3,6-disulfonic acid disodium)

An electrocatalytic detection of ascorbic acid on a nitroso-R modified polypyrrole electrode has been studied. This functionalized polypyrrole film was electropolymerized by constant potential method on a platinum electrode from solution including pyrrole as monomer and nitroso-R as anionic dopant. Electrocatalytic currents of ascorbic acid were linearly dependent on its concentration in the range of 0.12–18.54 mM, with detection limit and relative standard deviation of 0.02 mM and 1.32%, respectively. This modified electrode can be used for determination of ascorbic acid in various pharmaceutical samples. Also, electrochemical behavior of this system was studied by various methods (RDE voltammetry, chronoamperometry, hydrodynamic amperometry and cyclic voltammetry).     

Optical and chromaticity characteristics of cobalt 1-nitroso-2-naphthol-3,6-disulfonates

The optimum conditions of the complexation of cobalt with nitroso-R salt in the presence of and without ascorbic acid were found. Molar coefficients of chromaticity functions of the complexes were calculated, and it was demonstrated that cobalt(II) and cobalt(III) complexes can be distinguished only with the use of chromaticity functions, whereas their optical characteristics are nearly the same. For practical purposes, it is better to introduce ascorbic acid and to obtain the kinetically inert complex of cobalt(III) with nitroso-R salt.     

Determination of trace cadmium in waters by flame atomic absorption spectrophotometry after preconcentration with 1-nitroso-2-naphthol-3,6-disulfonic acid on Ambersorb 572

A procedure for the determination of trace amount of cadmium after adsorption of its 1-nitroso-2-naphthol-3,6-disulfonic acid chelate on Ambersorb 572 has been proposed. This chelate is adsorbed on the adsorbent in the pH range 3-8 from large volumes of aqueous solution of water samples with a preconcentration factor of 200. After being sorbed, cadmium was eluted by 5 mL of 2.0 mol L(-1) nitric acid solution and determined directly by flame atomic absorption spectrophotometery (FAAS). The detection limit (3sigma) of cadmium was 0.32 microg L(-1). The precision of the proposed procedure, calculated as the relative standard deviation of recovery in sample solution (100 mL) containing 5 microg of cadmium was satisfactory (1.9%). The adsorption of cadmium onto adsorbent can formally be described by a Langmuir equation with a maximum adsorption capacity of 19.6 mg g(-1) and a binding constant of 6.5 x 10(-3) L mg(-1). Various parameters, such as the effect of pH and the interference of a number of metal ions on the determination of cadmium, have been studied in detail to optimize the conditions for the preconcentration and determination of cadmium in water samples. This procedure was applied to the determination of cadmium in tap and river water samples.     

Atomic absorption spectrophotometric determination of trace copper in waters, aluminium foil and tea samples after preconcentration with 1-nitroso-2-naphthol-3,6-disulfonic acid on Ambersorb 572

An atomic absorption spectrophotometric method for the determination of trace copper after adsorption of its 1-nitroso-2-naphthol-3,6-disulfonic acid chelate on Ambersorb 572 has been developed. This chelate is adsorbed on the adsorbent in the pH range 1–8. The copper chelate is eluted with 5 ml of 0.1 mol l⁻¹ potassium cyanide and determined by flame atomic absorption spectrometry (FAAS). The selectivity of the proposed procedure was also evaluated. Results show that iron(III), zinc(II), manganese(II) and cobalt(II) at the 50 μg l⁻¹ level and sodium(I), potassium(I), magnesium(II), calcium(II) and aluminium(III) at the 1000 μg l⁻¹ level did not interfere. A high enrichment factor, 200, was obtained. The detection limit (3σ) of copper was 0.34 μg l⁻¹. The precision of the method, evaluated by seven replicate analyses of solutions containing 5 μg of copper was satisfactory and the relative standard deviation was 1.7%. The adsorption of copper onto Ambersorb 572 can formally be described by a Langmuir equation with a maximum adsorption capacity of 14.3 mg g⁻¹ and a binding constant of 0.00444 l mg⁻¹. The accuracy of the method is confirmed by analysing tomatoes leaves (NIST 1573a) and lead base alloy (NBS 53e). The results demonstrated good agreement with the certified values. This procedure was applied to the determination of copper in waters (tap, river and thermal waters), aluminium foil and tea samples.     

Separation and determination of metals as complexes of 1-nitroso-2-naphthol-6-sulphonic and 2-nitroso-1-naphthol-6-sulphonic acids

A sensitive ion-pair liquid-liquid extraction-spectrophotometric method has been developed for the determination of copper, palladium, iron and cobalt, based on the formation of metal complexes with 1-nitroso-2-naphthol-6-sulphonic acid or 2-nitroso-1-naphthol-6-sulphonic acid as primary ligand, and zephiramine as counter-ion. The coloured metal complexes obtained over different pH ranges are easily and quantitatively extracted into dichloromethane. The method has been tested with samples containing known amounts of copper, palladium, iron and cobalt in ultrapure water. The reagents provide a sensitive spectrophotometric method for determining these metals.     

Column chromatographic pre-concentration of iron(III) in alloys and biological samples with 1-nitroso-2-naphthol-3,6-disulphonate and benzyldimethyltetradecylammonium-perchlorate adsorbent supported on naphthalene using atomic absorption spectrometry

The solid ion-pair material produced from the reaction between benzyldimethyltetradecylammonium chloride (BDTA) and sodium perchlorate on naphthalene provides the basis for a simple, rapid and selective technique for pre-concentrating iron from up to 500 ml of aqueous solution. Iron reacts with disodium 1-nitroso-2-naphthol-3,6-disulphonate (Nitroso-R salt) to form a water-soluble coloured chelate anion. The iron chelate anion forms a water-insoluble, stable iron-Nitroso-R-BDTA complex on naphthalene packed in a column. Trace amounts of iron are quantitatively retained on naphthalene in the pH range 3.5-7.5 and at a flow-rate of 1-2 ml min-1. The solid mass is dissolved out from the column with 5 ml of N,N-dimethylformamide and iron is determined by means of an atomic absorption spectrometer at 248 nm. The calibration graph is linear for concentrations of iron over the range of 0.5-20 micrograms in 5 ml of final solution. The standard deviation and relative standard deviation were calculated. The detection limit of the method was 0.0196 micrograms ml-1 of iron. The sensitivity for 1% absorption was 0.072 microgram ml-1 (0.165 microgram ml-1 by direct atomic absorption spectrometry of aqueous solution). The proposed method was applied to the determination of iron in standard alloys and biological samples.     

7-Amino-1-naphthol-3,6-disulphonic acid (2R-acid) as a chromophoric reagent for trivalent iron

Summary 7-Amino-1-naphthol-3,6-disulphonic acid forms a stable red coloured complex with trivalent iron. Studies on the composition and stability of this complex are described.

---

Zusammenfassung 7-Amino-1-naphthol-3,6-disulfonsäure bildet mit Eisen(III) einen beständigen, rotgefärbten Komplex. Über die Untersuchungen zur Zusammensetzung und Stabilität dieses Komplexes wird berichtet.

     

New penta-nuclear and hepta-nuclear iron(II, III) complexes with ferrocenedicarboxylic acid

The reaction of [Fe₃EuO₂(O₂CCCl₃)₈(H₂O)(THF)₃] or [Fe₂CaO(O₂CCCl₃)₆(THF)₄] and [Fe₃O(O₂CCMe₃)₆(H₂O)₃]NO₃ with 1,1′-ferrocenedicarboxylic acid (fcdcH₂) yielded penta- and hepta-nuclear [Fe₄O₂(O₂CCCl₃)₆(fcdc)(THF)₂(H₂O)₂] and [Fe₆O₂(OH)₂(O₂CCMe₃)₁₀(fcdc)(H₂O)₂], respectively, which are the first X-ray structurally characterized clusters comprising Fe(III) and the ferrocenedicarboxylic organometallic ligand. Variable-temperature solid-state magnetic susceptibility measurements in the temperature range 1.8–300 K were carried out, and for both complexes a predominantly antiferromagnetic exchange interaction between the metal centres was observed. Mössbauer investigations show the presence of different environments for the Fe(III) atoms and confirm that no electron-transfer from Fe(II) of the ferrocene unit to Fe(III) of the central core occurs.     

Sectrophotometric determination of vanadium(V) with 7-amino-1-naphthol-3,6-disulphonic acid

Summary Vanadium(V) reacts with 7-amino-1-naphthol-3,6-disulphonic acid (2 R-acid) in the ratio 21, forming a red coloured chelate having maximum absorbance at 470 nm. The composition of the chelate has been found by the continuous variations and the mole ratio methods. The system obeys Beer's law between a range of 1.72 to 30.9 p. p. m. of vanadium and the sensitivity is 0.17g/cm² at pH 2.0, The reagent is found to be fairly selective for vanadium.

---

Zusammenfassung Vanadin(V) reagiert mit 7-Amino-l-naphthol-3,6-disulfonsäure im Ver-hältnis 21 und bildet ein rotes Chelat mit dem Absorptionsmaximum bei 470 nm, dessen Zusammensetzung nachJob bestimmt wurde. Zwischen 1,72 und 30,9 ppm V ist das Beersche Gesetz erfüllt. Die Empfindlichkeit beträgt 0,17g/cm² (Sandell) bei pH 2,0. Das Reagens ist für Vanadin ziemlich selektiv.

     

Separation and determination of metals as complexes of 1-nitroso-2-naphthol-6-suiphonic and 2-nitroso-1-naphthol-6-sulphonic acids. II. Liquid chromatography on c18 bonded and copolymer stationary phases

An ion-pair Chromatographic system for the separation of copper(II), palladium(II), iron(III) and cobalt(III) as ion-associates of their l-nitroso-2-naphthol-6-sulphonate and 2-nitroso-l-naphthol-6-sulphonate anionic complexes with organic ammonium compounds and inorganic cations has been studied. Isocratic and gradient elution methods were used, and the effects of column material, organic and aqueous modifiers, and pH of the eluent on the retention were examined. The elution time for the metal complex anions depends on the eluent, the proportion of organic solvent in the mobile phase, the pH of the eluent and the extraction coefficient of the compounds. The compounds were identified photometrically with a diode-array detector at wavelengths of 229, 254, 260, 298, 320 and 400 nm. The detection limits for the metals are at the ng/ml level.     

Solid complexes of iron(II) and iron(III) with rutin

Solid complex compounds of Fe(II) and Fe(III) ions with rutin were obtained. On the basis of the elementary analysis and thermogravimetric investigation, the following composition of the compounds was determined: (1) FeOH(C₂₇H₂₉O₁₆)·5H₂O, (2) Fe₂OH(C₂₇H₂₇O₁₆)·9H₂O, (3) Fe(OH)₂(C₂₇H₂₉O₁₆)·8H₂O, (4) [Fe₆(OH)₂(4H₂O)(C₁₅H₇O₁₂)SO₄]·10H₂O. The coordination site in a rutin molecule was established on the basis of spectroscopic data (UV–Vis and IR). It was supposed that rutin was bound to the iron ions via 4C=O and 5C—oxygen in the case of (1) and (3). Groups 5C–OH and 4C=O as well as 3′C–OH and 4′C–OH of the ligand participate in binding metals ions in the case of (2). At an excess of iron(III) ions with regard to rutin under the synthesis conditions of (4), a side reaction of ligand oxidation occurs. In this compound, the ligands’ role plays a quinone which arose after rutin oxidation and the substitution of Fe(II) and Fe(III) ions takes place in 4C=O, 5C–OH as well as 4′C–OH, 3′C–OH ligands groups. The magnetic measurements indicated that (1) and (3) are high-spin complexes.     

痕量铁催化对氨基二甲替苯胺-H酸显色反应

研究了在pH =5 .7混合酸 氢氧化钠缓冲介质中 ,铁 催化过氧化氢氧化对 氨基二甲替苯胺盐酸盐和H酸 钠盐的氧化偶联反应 ,考察了反应的最佳条件 ,建立了催化动力学光度法测定痕量铁 的新方法。该方法线性范围为 0 .0 0～ 0 .0 2mg L ;检出限为 2 .1× 1 0 - 7g L。直接用于自来水及湖水中铁 的测定 ,结果满意     

Gaseous iron(II) and iron(III) complexes with BINOLate ligands

Electrospray ionization (ESI) of dilute solutions of 1,1'-bi-2-naphthol (BINOL) and iron(II) or iron(III) sulfate in methanol/water allows the generation of monocationic complexes of iron and deprotonated BINOL ligands with additional methanol molecules in the coordination sphere, and the types of complexes formed can be controlled by the valence of the iron precursors used in ESI. Thus, iron(II) sulfate leads to [(BINOLate)Fe(CH3OH)n]+ complexes (n=0-3), whereas usage of iron(III) sulfate allows the generation of [(BINOLdiate)-Fe(CH3OH)n]+ cations (n=0-2); here, BINOLate and BINOLdiate stand for singly and doubly deprotonated BINOL, respectively. Upon collision-induced dissociation, the mass-selected ions with n>0 first lose the methanol ligands and then undergo characteristic fragmentations. Bare [(BINOLdiate)Fe]+, a formal iron(III) species, undergoes decarbonylation, which is known as a typical fragmentation of ionized phenols and phenolates either as free species or as the corresponding metal complexes. The bare [(BINOLate)Fe]+ cation, on the other hand, preferentially loses neutral FeOH to afford an organic C20H12O+* cation radical, which most likely corresponds to ionized 1,1'-dinaphthofurane.     

Cobalt(II) and iron(III) complexes with 2-substituted benzimidazole derivatives

Summary FeCl₃ and the primary amines 2-aminobenzimidazole (abi) and 2(2-aminophenyl)benzimidazole (apbi) give complexes for which spectroscopic and magnetic data suggest a pentacoordinate [FeCl₄].The reactions of complexes of primary amines of CoCl₂ and FeCl₃ with the carbonyl compounds acetylacetone (Hacac) and pyridylcarbaldehyde (pyc) yield complexes which contain the Schiff bases from the condensation of the amines and the carbonyl groups.Analytical data indicate formulae [CoCl₂(abiacac)₂], [CoCl₂(abipyc)], [FeCl₃(abiacac)], [FeCl₃(abipyc)₂] and [FeCl₃(apbipyc)] for the complexes. The cobalt(II) complexes are pseudo-tetrahedral, while the iron complexes are tetra-, penta-, or hexa-coordinate, as deduced from spectroscopic and magnetic measurements.     

Polarographic determination of iron(II) and iron(III) complexes with edta

The iron(II) and iron(III) complexes with EDTA can be determined separately and in mixtures in acetate-buffered medium at pH 4.0. The E_{$\text{1}\text{2}$}values are in the range ?0.105 to ?0.112 V vs. SCE. Linear calibration plots are obtained over the range 0–1.0 mM for each oxidation state. A sample-handling procedure for avoiding oxidation of iron(II) species is described. It is shown that the acetate buffer system does not affect the stability of the iron-EDTA complexes.