Liquid-liquid extraction of ion-association complexes of cobalt(II)-4-(2-pyridylazo)resorcinol with ditetrazolium salts

Abstract

The formation and liquid-liquid extraction of ion-association complexes between Co(II)-4-(2-pyridylazo)resorcinol (Co(II)-PAR) anionic chelates and cations of three ditetrazolium chlorides (DTC), i.e., blue tetrazolium chloride (BTC), neotetrazolium chloride (NTC) and nitro blue tetrazolium chloride (NBTC), were studied. The optimum conditions for the formation and solvent extraction of the ion-association complex chelates were determined. It has been found that in the Co(II)-PAR-DTC systems, the reactants are present in the mole ratio 1:2:1 and the general formula of complexes was suggested. The extraction equilibria were investigated and quantitatively characterized by the equilibrium constants and the recovery factors. The analytical characteristics of the complexes were calculated.

First Synthesis of 2-Amino-5-hydroxy-4H-chromene-3-carbonitriles from 4-(2-Pyridylazo)resorcinol

“…4-(2-Pyridylazo)resorcinol (PAR, 4), available in the form of sodium salt monohydrate, has long been actively used in analytical chemistry as a non-selective tridentate complexing agent for the extraction and concentration of heavy metal ions, as a metallochromic indicator for complexometric titration, reagent for the photometric determination of analytes (for reviews, see [19][20][21][22][23]). In recent years, PAR has been actively used to create optical sensors and test materials for the determination and extraction of heavy metals [24][25][26][27], spectrophotometric analysis of transition metals in catalysts [28], extraction of Rh 3+ [29], Ga 3+ [30], Ir 4+ [31], and Co 2+ ions [32], obtaining charge-transfer complexes with aromatic nitro compounds [33], etc. However, as far as we know, 4-(2-pyridylazo)resorcinol has not yet been used as a reagent for fine organic synthesis.…”

Complex Formation in a Liquid-Liquid Extraction System Containing Co(II), 4-(2-Thiazolylazo)resorcinol and Monotetrazolium Salt

“…In our previous research the ion associates of cobalt(II) were described by spectrophotometric investigation of eight different liquid-liquid extraction systems. [23][24][25][26] The extraction equilibria were characterized quantitatively (association constant, distribution constant, extraction constant and recovery factor) and the analytical characteristics (molar absorptivity, Sandell's sensitivity, Divarova et al : Complex Formation in a Liquid-Liquid Extraction ... adherence to Beer's law, limit of detection, limit of quantification) were calculated. The present work is a part of a thorough and comprehensive study on the ion-associated complexes of cobalt(II) with azo derivatives of resorcinol and mono-or ditetrazolium salts.…”