Spectrophotometric study of the acid-base and optical properties of the 5-bromo and 5-chloro derivatives of 2-(2-pyridylazo)-5-(diethylamino)phenol (BrPADAP, ClPADAP) and their complexation equilibria with zinc(II) ions

1982 ◽  
Vol 47 (10) ◽  
pp. 2676-2691 ◽  
Author(s):  
Miroslav Macka ◽  
Vlastimil Kubáň
Keyword(s):  
Equilibrium Constants ◽  
Spectrophotometric Study ◽  
Graphical Analysis ◽  
Alkaline Media ◽  
Acid Base ◽  
Ethanol Medium ◽  
Triton X ◽  
Mixed Water ◽  
Derivatives Of

The optical and acid-base characteristics of BrPADAP and ClPADAP were studied in mixed water-ethanol and water-DMF media and in 10% ethanol medium in the presence of cationic, anionic and nonionic tensides. The composition, optical characteristics, molar absorption coefficients and equilibrium constants of the ML and ML2 complexes with zinc(II) ions were found by graphical analysis and numerical interpretation of the absorbance curves by the modified SQUAD-G program. Optimal conditions were found for the spectrophotometric determination of Zn(II) in the presence of 0.1% Triton X-100 or 1% Brij 35 in alkaline media with pH = 6.5-10. BrPADAP and ClPADAP are the most sensitive reagents (ε = 1.3-1.6 . 105 mmol-1 cm2 at 557 and 560 nm, respectively) for the determination of zinc with high colour contrast of the reaction (Δλ = 104 nm) and selectivity similar to that for the other N-heterocyclic azodyes (PAN, PAR, etc.).

Spectrophotometric study of the complexation equilibria of cadmium ions with 5-bromo and 5-chloro derivatives of 2-(2-pyridylazo)-5-diethylaminophenol (BrPADAP, ClPADAP)

1983 ◽  
Vol 48 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Vlastimil Kubáň ◽  
Miroslav Macka
Keyword(s):  
Equilibrium Constants ◽  
Spectrophotometric Study ◽  
Graphical Analysis ◽  
Optimal Conditions ◽  
Cadmium Ions ◽  
Brij 35 ◽  
Ethanol Medium ◽  
Triton X ◽  
Derivatives Of

The composition, optical characteristics, molar absorption coefficients and equilibrium constants of the reactions of formation of the ML and ML2 complexes of both reagents with cadmium(II) ions were determined by graphical analysis and numerical interpretation of the absorbance-pH curves by the modified SQUAD-G program. Optimal conditions were proposed for the spectrophotometric determination of Cd in 10% v/v ethanol medium in the presence of 0.1% w/v Triton X-100 or 1% w/v Brij 35. BrPADAP and ClPADAP are the most sensitive spectrophotometric reagents for the determination of cadmium(II) ions (ε = 1.28-1.44 . 105 mmol-1 cm2 at 560 nm and pH 8.0-9.5) with a high colour contrast in the reaction (Δλmax ~117 nm) and a selectivity similar to that of other N-heterocyclic azodyes (PAR, PAN, etc.).

Spectrophotometric study of the interaction of Chromazurol S and Eriochromazurol B with surface active substances - tensides

1981 ◽  
Vol 46 (5) ◽  
pp. 1090-1106 ◽  
Author(s):  
Irena Burešová ◽  
Vlastimil Kubáň ◽  
Lumír Sommer
Keyword(s):  
Critical Micellar Concentration ◽  
Spectrophotometric Study ◽  
Conditional Stability ◽  
Acid Base ◽  
Binary Complexes ◽  
Chromazurol S ◽  
Acid Base Equilibrium ◽  
Poorly Soluble ◽  
Conditional Stability Constants ◽  
Triton X

The acid-base and optical properties of Chromazurol S and Eriochromazurol B in the presence of 1 . 10-6 - 2 . 10-2M solutions of cetylpyridinium bromide, cetyltrimethylammonium bromide and 1-ethoxycarbonylpentadecyltrimethylammonium bromide (Septonex) and 0.001-1.0% w/v solutions of octylphenolpolyethylene glycol ether (Triton X-100), polyoxyethylenemonolauryl ether (Brij 35) and lauryl sulphate sodium salt were determined by graphical and numerical interpretation of absorbance curves. The poorly soluble ion associates, which can be extracted into chloroform and which have the defined composition [LH4-nn-.n T+] or [LH3-nn-.n T+] are formed at submicellar concentration of the tenside. In regions close to the critical micellar concentration of the tenside, soluble binary complexes of the acid-base forms of the reagent are formed with tenside micelles. The conditional stability constants of the reagent acid-base equilibrium depend on the type and concentration of the tenside, on the reagent concentration, on the concentration and type of inorganic acid anions and on the ionic strength of the solution. The mechanism of interaction of the reagent with the tenside and the probable structure of the binary species are discussed.

Spectrophotometric study of reaction of sodium 6-hydroxy-5-dibenzo(a,j)phenoxazone-11,13-disulfonate with aluminium ions in the presence of cationoid tensides

1980 ◽  
Vol 45 (4) ◽  
pp. 1227-1235
Author(s):  
Nguyen Truong Son ◽  
Jan Lasovský ◽  
Eduard Ružička
Keyword(s):  
Acidic Medium ◽  
Equilibrium Constants ◽  
Ternary Systems ◽  
Photometric Determination ◽  
Spectrophotometric Study ◽  
Ternary Complexes ◽  
Medium Ph ◽  
Binary And Ternary Systems

In weakly acidic medium, pH 3.5-6.5, the title dye forms with aluminium ions a complex with the Al : L ratio 1 : 1. In the presence of cetylpyridinium or carbethoxypentadecyltrimethylammonium, ternary complexes AlL3Sr (r = 6 or 9, respectively) are formed. The equilibrium constants of the complexing equilibria in the binary and ternary systems concerned were calculated, and a method of photometric determination of aluminium has been suggested.

Spectrophotometric study of the reaction of dyes of the alizarin green series with indium(III) ions in the presence of cationic tensides

1980 ◽  
Vol 45 (3) ◽  
pp. 703-714 ◽  
Author(s):  
Nguyen Truong Son ◽  
Eduard Ružička
Keyword(s):  
Equilibrium Constants ◽  
Ternary Systems ◽  
Spectrophotometric Study ◽  
Ternary Complexes ◽  
Conditional Stability ◽  
Acid Media ◽  
Weakly Acid ◽  
Cetyl Pyridinium ◽  
Conditional Stability Constants

The reactions of four dyes of the alizarin green series with indium(III) ions were studied. In weakly acid media of pH 4-6.5, binary InL and InL2 complexes are formed in solution. In the presence of cationic tensides containing cetyltrimethylammonium and cetyl pyridinium, defined ternary complexes, InL3S6, are formed in the solution. The conditional stability constants of the binary In-L complexes and the equilibrium constants of the studied complexing ternary systems were calculated and a procedure for the photometric and chelometric determination of indium was proposed.

Spectrophotometric study of complexation equilibria and of a method for the determination of Fe(III) ions with 4-(2-pyridylazo)resorcinol and 4-(2-thiazolylazo)resorcinol

1979 ◽  
Vol 44 (2) ◽  
pp. 374-392 ◽  
Author(s):  
Ellena Russeva ◽  
Vlastimil Kubáň ◽  
Lumír Sommer
Keyword(s):  
Stability Constants ◽  
Spectrophotometric Determination ◽  
Equilibrium Constants ◽  
Spectrophotometric Study ◽  
Component Concentration ◽  
Optimum Conditions ◽  
Ferric Ions ◽  
Absorption Coefficients ◽  
Basic Parameters

The composition, molar absorption, coefficients, equilibrium constants and stability constants for the MLH, ML, M(LH)2 and ML2 complexes have been determined graphically using slope-intercept transformations and numerically from the absorbance-pH curves and from the absorbance dependence on the component concentration, using the PRCEK III and SPEKTFOT programs, or from the continuous variation plots using the JOBCON program. The optimum conditions were found for a spectrophotometric determination of ferric ions with TAR and PAR reagents in pure solutions. The basic parameters of the analytical curves were evaluated using the STAT program.

scholarly journals SYNTHESIS, COORDINATION AND ACID-BASE PROPERTIES OF MESO-DINITROSUBSTITUTED DERIVATIVES OF 5,15-DIPHENYL-β-OCTAALKYLPORPHINE

2018 ◽  
Vol 61 (6) ◽  
pp. 17
Author(s):  
Svetlana G. Pukhovskaya ◽  
Yulia B. Ivanova ◽  
Dmitry A. Erzunov ◽  
Aleksander S. Semeykin ◽  
Sergei A. Syrbu
Keyword(s):  
Spectral Characteristics ◽  
Spectrophotometric Titration ◽  
Basicity Constant ◽  
Acidity Constant ◽  
Electronic Effects ◽  
Acid Base ◽  
Electronic Effects Of Substituents ◽  
Derivatives Of ◽  
Base Properties

Presented work shows results of synthesis and spectrophotometric researches on properties of meso-dinitrosubstituted derivatives of 5,15-diphenyl-β-octaalkylporphyrin nitroderivatives in comparison with 2,8,12,18,3,7,13,17-octaethylporphyrin and 2,3,7,8,12,13,17,18-octaethyl-5,15-dinitroporphyrin. The method of spectrophotometric titration with perchloric acid (for determining the basicity constant) and 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) was used in order to study the acid-base properties of porphyrins, namely to determine the acidity constant. The spectral characteristics of the ionized forms of 5,15-dinitro-10,20-diphenyl-3,7,13,17-tetramethyl-2,8,12,18-tetraethylporfin-F (I) and 5,15-dinitro-10,20-bis(4-nitrophenyl)-2,8,12,18-tetramethyl-3,7,13,17-tetraethylporphyrin (II) and the corresponding total constants of the acidic (pKa (I) = 6.00 and pKa (II) = 5.27) and the basic (pKb (I) = 19.78 and pKb (II) = 19.83) ionization were provided. The reaction of complexation of porphyrins with zinc acetate was studied by spectrophotometric method in pure acetonitrile and in mixed AN + DBU solvent. The influence of the degree of deformation of the tetrapyrrole macroring, the electronic effects of substituents and the acidity of the medium on the coordination and acid-base properties of porphyrins was analyzed. It was shown that the reactions of formation of metalloporphyrins with anionic porphyrin forms proceed with much higher rates compared to molecular ones, that is accompanied with a decrease in the energy parameters of the reaction. This is evidently due to the absence of energy costs for the deformation and cleaving N-H bonds of the reaction center, as well as the stronger polarization of the molecule, and as a consequence, the higher degree of solvation of anionic forms of porphyrins in the transition state. Thus, the determination of the conditions for the existence of dianionic forms of porphyrins gives grounds for the development of new sensor systems for the recognition and determination of the concentration of metal cations in liquid media due to a sharp increase in the rate of formation of metalloporphyrins in the presence of an organic base.Forcitation:Pukhovskaya S.G., Ivanova Yu.B., Erzunov D.A., Semeykin A.S., Syrbu S.A. Synthesis, coordination and acid-base properties of meso-dinitrosubstituted derivatives of 5,15-diphenyl-β-octaalkylporphine. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 6. P. 17-28

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