Thermodynamic study of the binding of hexathia-18-crown-6-tetraone with some transition and heavy metal ions in dimethyl sulfoxide solution

Abstract

A conductance study of the interaction between CO2`, Ni2`, Cu2`, Zn2`, Cd2`, Pb2`and Hg2`ions with hexathia-18-crown-6-tetraone in dimethyl sulfoxide solution has been carried out at various temperatures. Formation constants of the resulting 1 : 1 complexes were determined from the molar conductanceÈmole ratio data and found to vary in the order Hg2` [ Pb2`[ Cd2`[ Cu2`[ Ni2`[ Co2`[ Zn2`. The enthalpy and entropy of complexation were determined from the temperature dependence of the formation constants. All complexes formed were enthalpy stabilized but entropy destabilized.

Novel Dy(III) Sensor Based on a New Bis‐Pyrrolidene Schiff's Base

“…The results showed that, in all cases, the ligand to cation mole ratio was 1. The formation constants (K f ) of the resulting 1 : 1 complexes were evaluated by the computer fitting of the molar conductance-mole ratio data to appropriate equations [20,21].The stability of the resulting complexes were varied in the order of:…”

Ultra-trace monitoring of copper in environmental and biological samples by inductively coupled plasma atomic emission spectrometry after separation and preconcentration by using octadecyl silica membrane disks modified by a new schiff's base

“…Thus, in preliminary experiments, the complexation of SBTD with a number of alkali, alkaline earth, transition and heavy metal ions was studied conductometrically in acetonitrile solution at 25±0.05 °C 24,25 , in order to obtain information about the stability and selectivity of the resulting complexes. The complex formation constant, K f , of the resulting 1:1 complexes were evaluated by computer fitting of the molar conductance-mole ratio data to appropriate equations 24,25 , and the results are summarized in Table 1. As can be seen, the SBTD could act as a suitable complexing agent for pre-concentration and separation of copper ions via solid extraction, by using octadecyl bonded silica membrane disks.…”

“…The break-through volume of sample solution by dissolving 2 µg of copper in 25,50,100,250,500,750,1000,1250,1500,1750,2000,2250,2500, 3000 and 3500 mL of water, was tested and the recommended procedure was followed and the results showed that the extraction by modified membrane disk was found to be quantitative, up to 2500 mL. Thus, the break-through volume for the method is more than 2500 mL.…”

Quantitative Analysis of Holmium Ion by a Ho3+ Ion‐Selective Sensor Based on a Symmetric Thio‐Schiff's Base

“…[27][28][29][30][31] The complex formation constant, K f , shows the selectivity of the used ionophore toward Ho 3＋ ions (K f 5.7×10 6 ) among the all other cations tested.…”