Analytical applications of picolinealdehyde salicyloylhydrazone: II. Extraction and spectrophotometric determination of vanadium(V)

Picolinealdehyde salicyloylhydrazone reacts with vanadium(V) to produce a yellow 1:1 complex (λ_max = 400 nm, ? = 2.17 × 10⁴ liters · mol^?1 cm^?1) in aqueous ethanolic solution. The yellow complex can be extracted into chlorobenzene (λ_max = 425 nm, ? = 2.16 × 10⁴ liters · mol^?1 cm^?1) and used for the spectrophotometric determination of trace amounts of vanadium. Interferences have been investigated. The method has been applied to the determination of vanadium in steel and in lead concentrates.     

2,2′-Dihydroxybenzophenone thiosemicarbazone as a spectrophotometric reagent for the determination of copper,cobalt, nickel,and iron trace amounts in mixtures without previous separations

2,2′-Dihydroxybenzophenone thiosemicarbazone forms complexes with Cu(II) (λ_max = 385 nm, ? = 8.60 × 10³ liter · mol^?1 · cm^?1); Ni(II) (λ_max = 380 nm, ? = 15.4 × 10³ liter · mol^?1 · cm^?1); Co(II) (λ_max = 380 nm, ? = 12.3 × 10³ liter · mol^? · cm^?1); and Fe(III) (λ_max = 365 nm, ? = 7.9 × 10³ liter · mol^?1 · cm^?1) and have been applied to the analysis of these metal ions in binary, ternary, and quaternary mixtures. The determination procedures are based exclusively on the different pH values of the formation complexes, hence the extraction step is not necessary.     

DI-2-Pyridyl ketone thiosemicarbazone as an analytical reagent

The synthesis, characteristics and analytical reactions of di-2-pyridyl ketone thiosemicarbazone are described. This compound reacts with iron(II) (λ_max=410mm, ε = 9.3 · 10³ 1 mol^?1 cm^?1), nickel(II) (λ_max =395 mm ε =19.6·10³ 10 mol ^?1 cm ^-1), cobalt(II) (λ_max = 415 nm. ε = 1.0 · 10⁴ mol^?1 cm^?1 ) and copper(I) (λmax =395mm ε = 11.3 · 10³ mol^?1 cm^?1) A critical comparison of di-2-pyridyl ketone, picolinaldehyde and bipyridylglyoxal thiosemicarbazones as analytical reagents is given.     

Analytical applications of 3-(2′-thiazolylazo)-2,6-diaminopyridine: Spectrophotometric determination of palladium

3-(2′-Thiazolylazo)-2,6-diaminopyridine reacts with palladium(II) in strongly perchloric acid media, to produce a blue 1:1 complex (λ_max = 665 nm, ? = 1.37 × 10⁴ liters · mol^?1 · cm^?1), which allows the spectrophotometric determination of 0.6 to 4.5 ppm of palladium. The method is applied to the determination of palladium in small samples of hydrogenation catalysts.     

Structure and properties of 2-[(E)-2-(4-dipropylaminophenyl)-1-ethenyl]-1,3,3-trimethyl-3H-indolium chloride

The structure of styryl dye, 2-[(E)-2-(4-dipropylaminophenyl)-1-ethenyl]-1,3,3-trimethyl-3H-indolium chloride (I), was investigated using methods such as UV-VIS, fluorescence spectroscopy, and NMR (¹H, ¹³C, APT, HMQC, COSY) and also by examining its electrochemical properties. A study of the acid-base properties revealed the existence of three different forms of the dye. The mechanisms of protolysis and hydrolysis are discussed. The reagent exists in a reactive single-charged form I ⁺ over a wide range of acidity (pH 4–11). The optimum analytical wavelength of the singlecharged form is 550 nm, where the molar absorptivity is 5.51 × 10⁴ L mol^?1 cm^?1. The values of the optimum analytical wavelength and molar absorptivity of the protolysed and hydrolysed forms are: λ _max(I-H²⁺) = 380 nm, ?(I-H²⁺) = 2.01 × 10⁴ L mol^?1 cm^?1; λ _max(I-OH) = 320 nm, ?(I-OH) = 1.12 × 10⁴ L mol^?1 cm^?1. A theoretical study of the spectral and chemical properties of I was carried out by performing quantum chemical calculations.     

Spectrophotometric study of 1,2,5,8-tetrahydroxyanthraquinone-In(III) complex: Determination of In (III)

The 1,2,5,8-tetrahydroxyanthraquinone (quinalizarin) forms a colored complex with the ion In(III) in dimethylformamide-water solution. The 3:1 (R:In(III)) complex shows a λ_max of 565 nm and a molar absorptivity of 4.59 × 10⁴ liters mol^?1 cm^?1. A new method for the spectrophotometric determination of In(III) between 0.2 and 2.2 ppm with a relative error of 1.57% is proposed.     

Spectrophotometric Study of 1, 3-Cyclohexanedione Bisthiosemicarbazone Monohydrochloride -Bi (III) Complex. Determination of Bi (III)

Abstract

The spectrophotometric study was made of red-violet 1, 3-cyclohexanedione bis-thiosemicarbazone-Bi (III) in an acidic dimethylformamide-water solution (λ_max = 540 nm, ? = 3.3 × 10^?4 1. mol^?1. cm^?1, stoichiometry 3:1, apparent stability constant (6.0 × 10¹⁰). A new method for the spectrophotometric determination of Bi (III) is proposed for concentrations between 0.7 and 7.4 ppm. The relative error (95 % confidence level) is 0.5 % for 3.7 ppm of Bi (III).

The extraction with methyl isobutyl ketone of the red-violet complex was also studied spectrophotometrically (λ_max = 550 nm, ? = 3.34 × 10⁴ 1. mol^?1.cm^?1, stoichiometry 2:1). A new method for the extraction-spectrophotometric determination of Bi (III) is proposed for concentrations, in aqueous phase, between 0.2 and 1.2 ppm. The relative error (95 % confidence level) is 0.8 % for 0.9 ppm of Bi (III).     

Analytical applications of picolinealdehyde salicyloylhydrazone: Spectrophotometric determination of nickel and zinc

With a view to the use of picolinealdehyde salicyloylhydrazone as analytical reagent, a study of the physical properties and chemical reactions of this substance has been carried out. It reacts with nickel (λ_max = 375 nm, ? = 3.9 × 10⁴M^?1cm^?1) or zinc (λ_max = 365 nm, ? = 4.8 × 10⁴M^?1cm^?1) to produce a yellow 1:2 complex in both cases. Spectrophotometric determinations of trace amounts of nickel and zinc have been established.     

Extraction and spectrophotometric determination of trace amounts of tin(II) with diphenylglyoxal bis(2-hydroxybenzoylhydrazone)

Diphenylglyoxal bis(2-hydroxybenzoylhydrazone) has been used as a sensitive reagent for the spectrophotometric determination of tin. This reagent forms an orange-yellow complex with stannous ion at pH 3.5–7.0 (λ_max = 455 nm, ? = 2.25 × 10⁴ liter mol^?1/cm^?1 while no reaction is observed with quadrivalent tin. The colored complex extracted into isobutyl methyl ketone has been used for the spectrophotometric determination of trace amounts of tin(II). The molar absorption in the organic solvent is 3.54 × 10⁴ liter mol^?1 cm^?1 and the compound shows its maximum absorbance at 455 nm. The interferences of foreign ions have been determined.     

Sensitive spectrophotometric determination of La(III) with 1-(2-pyridylazo)-2-naphthol

A simple and sensitive method for spectrophotometric determination of lanthanum has been developed. At pH 9.6, in presence of 50% ethanol, lanthanum reacts with 1-(-2-pyridylazo)-2-naphthol (PAN) to form a red complex which has two absorption maxima, at 545 and 510 nm. The molar absorptivity at 545 nm is 0.55 × 10⁴ liters · mol^?1 cm^?1. On the other hand, lanthanum reacts with PAN in pure ethanol to form a red complex at 530 nm, with high molar absorptivity (8 × 10⁴ liters · mol^?1 cm^?1).     

Analytical applications of 4-(4′-methyl-2′-thiazolylazo)-2-methyl-resorcinol: Spectrophotometric determination of vanadium

4-(4′-Methyl-2′-thiazolylazo)-2-methyl-resorcinol reacts with vanadium (V) to produce a bluish-violet 1:1 complex (λ_max = 560 nm, ? = 2.50 × 10⁴M^?1 · cm^?1, 50% methanol-water medium), which allows the spectrophotometric determination of 0.1 to 1.4 ppm of vanadium. The method has been applied to the determination of vanadium in several low-alloy steels.     

Extractive spectrophotometric determination of nitrite in polluted waters

Nitrite is diazotised with p-nitroaniline in hydrochloric acid and coupled with 8-quinolinol in alkaline medium to give a purple azo dye (λ_max = 550 nm, ? = 3.88 × 10⁴ l mol^-1 cm^-1). Extraction of the dye into 3-methyl-1-butanol shifts the absorption maximum to 570 nm and improves the apparent molar absorptivity to 5.852 × 10⁴ l mol^-1 cm^-1. Beer's law is obeyed for 0.01–0.06 ppm nitrite. The Sandell sensitivity is 0.00078 μg cm^-2. The method is applicable to polluted waters.     

1,3-Cyclopentanedione bis(4-methylthiosemicarbazone) monohydrochloride as a spectrophotometric reagent for the determination of lodate in acetic and perchloric acid media

1,3-Cyclopentanedione bis(4-methylthiosemicarbazone) monohydrochloride produces colored solutions with iodate ions in acid medium. The yellow color obtained has been used to proposed Spectrophotometric methods for determination of IO₃^? in the concentration range 1.0–11.0 ppm in acetic acid medium (molar absorptivity 1.08 × 10⁴ liters mol^?1 cm^?1 at a wavelength of 415 nm) and 0.5–8.0 ppm in perchloric acid medium (molar absorptivity 2.05 × 10⁴ liters mol^?1 cm^?1 at a wavelength of 400 nm).     

TETRAETHYLPHYROPHOSPHITE AS A BRIDGING LIGAND IN A BIMETALLIC RUTHENIUM(II) - RUTHENIUM(II) COMPLEX

Abstract

The complex μ-TEPP-trans-bis[P(OEt)₃Ru(NH₃)₄]₂(PF₆)₄ has been prepared and characterized by microanalysis, vibrational and electronic spectroscopy (λ_max=299 nm, ?=6.4 × 10² M^?1 cm^?1; λ_max=262 nm, ?=8.6 × 10² M^?1 cm^?1), and cyclic voltammetry (E°'=+0.64 V versus S.C.E., 25°, μ=0.10 M NaCf₃COO, C_H+=1 × 10^?3 M). In aqueous solutions, ([H⁺] > 1 × 10^?4 M), the binuclear species undergoes hydrolysis yielding the mononuclear species trans-(Ru(NH₃)₄P(OEt)₃(H₂O)]²⁺ with a specific rate constant of 2.4 × 10^?5 sec^?1 at 25° δH^#=84.5 kJ mol^?1; δS^#=?49.4 J mol^?1 K^?1.     

Analytical study of the phenyl-2-pyridyl ketone azine-palladium system. Photometric determination of palladium

Phenyl-2-pyridyl ketone azine reacts with palladium(II) to produce a yellow 1:1 complex (λ_max = 425 nm, ? = 10.4 × 10³M^?1 cm^?1 in aqueous ethanolic solution) and a red-violet 3:1 complex (λ_max = 530?540 and 380?390 nm). The yellow complex in aqueous ethanolic solution has been used for the spectrophotometric determination of trace amounts of palladium. The method has been applied to the determination of palladium in some catalysts and one mineral.     

Spectrophotometric determination of zinc in pharmaceutical preparations with biacetyl mono(2-pyridyl)-hydrazone

The biacetyl mono(2-pyridyl)hydrazone (BPH) spectrophotometric procedure for zinc (λ_max = 440 nm, ? = 52,100 liters mol^?1 cm^?1, 1 ml BPH at 0.25% in ethanol/25 ml, 20% of ethanol as medium, boric acid/sodium hydroxide, pH 10, buffer) has been applied to the determination of zinc in pharmaceutical preparations (ophthalmic solutions, mouthwash liquids, and cream ointments) with good results.     

The tris(picolinate)vanadate(II) ion: Redox properties and electron transfer kinetics with cobalt(III) amines

Vanadium(II) ions form with the pyridine-2-carboxylate ligand a deep blue, tris-substituted complex absorbing at 660 nm (ε = 7.2 × 10³ M^?1) cm^?1) with a shoulder at 450 nm. Reversible spectroelectrochemistry and cyclic voltammetry were observed for this complex, with E_{$\text{1}\text{2}$} = ?0.448 V vs NHE, and ΔS_rc^θ = ?6 cal · mol^?1 · deg^?1. Electron transfer kinetics with [CO(en)₃]³⁺ led to k₁₂ = 3100 M^?1 s^?, ΔH^≠ = 12.4 kcal · mol^?1 and ΔS^≠ = ?0.9 cal · mol^?1 · deg^?1 (I = 0.10 M). For the related [Co(NH₃)₆]³⁺ complex, k₁₃ = 1.9 × 10⁴ M^?1 s^?1. The self-exchange rate constant and activation parameters were analysed in terms of relative Marcus theory.     

A Simple Synthetic Method of a 1,3,5‐Triazine UV Absorbent CGL‐479 and Its Characterization

As a novel ultraviolet (UV) absorbent with excellent performance in UVA section (320 ~ 400 nm), 2‐{2‐hydroxy‐4‐[(octyloxycarbonyl)ethylideneoxy]phenyl}‐4,6‐Bis(4‐biphenylyl)‐1,3,5‐triazine (CGL‐479) was synthesized in a simple method with a total yield of 45.3% in four steps. Its outstanding UV absorption capability (λ_max = 326 nm, ε_max = 4.15 × 10⁴ L?mol^?1?cm^?1), high thermostability [T₅ (the temperature of losing 5% in weight) = 385 °C], and compatibility with polymer materials make it a potential substitute of the traditional UV absorbents.     

Spectrophotometric determination of titanium with Chrome Azurol S (or Eriochrome Cyanine R) in the presence of some cationic surfactants

A new sensitive spectrophotometric method for titanium determination, based on the ternary Ti-Chrome Azurol S (CAS)-cetyltrimethylammonium (CTA) system, was developed. The molar absorptivity is 7.3 × 10⁴ liters mol^?1 cm^?1 at λ_max = 565 nm. The maximum absorbance is attained in 5 min at pH 1.3 ± 0.1 and at CAS and CTA concentrations of 1.5 × 10^?4 and 5 × 10^?4M, respectively. Zirconium and hafnium in the presence of ascorbic acid are the only interfering metals. Hydrogen peroxide and EDTA interfere with the titanium determination as well. The proposed method was applied to the determination of titanium (about 1 × 10^?2%) in aluminum metal. The method, based on the Ti-Eriochrome Cyanine R-CTA system, is similar to the above method. Among other cationic surfactants, cetylpyridinium chloride (CP) and zephiramine were examined. The color effects when using CP, and especially zephiramine, are worse than in the presence of CTA.     

Sensitive spectrophotometric determination of gallium with bromopyrogallol red in the presence of surfactants

Gallium in the presence of surfactants (NTGE and CTA) forms with BPR a violet ternary complexes with λ_max at 615 and 625 nm, respectively, with molar absorptivities of 7.0 × 10⁴ and 1.3 × 10⁵ liters mol^?1 cm^?1. These complexes can be advantageously used for the determination of gallium. The molar ratio of gallium to BPR, which is 1:1 in the binary complex, increases to 1:3 in the ternary complex. The presence of surfactants changes the number of BPR molecules bonded to gallium. This is the main factor in the increase in color intensity. Numerous metals interfere. Gallium can be separated by extraction of gallium from 7 M hydrochloric acid with diisopropyl ether.