New heavy metal ion-selective macrocyclic ligands with mixed-donor atoms and their extractant properties

Complexation and Adsorption Studies of 27-Membered Dioxadiazapentathia Macrocycles with Some Transition Metals

“…(4) in Eq. (3) and taking the log of both sides give the following logarithmic expression, which is valid for the above extraction system (23)(24)(25)(26). …”

“…Picrate extraction experiments were performed according to published procedures (23)(24)(25)(26). Solvent extraction experiments were carried out using the aqueous metal picrate solutions, which were prepared from a mixture of the metal nitrates (Pb(NO 3 and picric acid in deionized water.…”

NMR study of the stoichiometry and stability of complexation reaction between Mg2+, Ca2+, Sr2+ and Ba2+ ions and 60-crown-20 in binary acetonitrile solvent mixtures

“…One reason for the interest in this field is that macrocyclic ligands have enhanced the promotion of selective binding and transformation of a large variety of substrates such as inorganic or organic cations, anionic species and neutral molecules [4][5][6]. Also the complexation reaction of macrocyclic ligands is very useful for construction of selective membrane-sensors for different metal ions [7][8][9][10]. Despite the interesting properties of large crown ethers (i.e., larger than 18-crown-6), including their highly flexible geometrics in solution, which lets them adapt their conformation for optimum complexation with guest species, there have been no considerable studies on the complexation reactions of these compounds with metal ions [11,12].…”

Synthesis, characterization, and metal extraction studies of a new macrobicyclic ligand

“…12 A series of closely related macrocyclic and macrobicyclic systems and their extractant properties were reported by Ocak et al They demonstrated that the presence of soft donor atoms in the macrocyclic system enhanced the selective extraction for soft metal ions such as silver(I) and mercury(II). 13,16,17 According to the HSAB concept, the attachment of nitrogen and sulfur donor atoms to a macrocyclic cavity increases their selectivity towards soft transition metal cations. 10 Another interesting extractant used for metal cation and anion extraction is based on the calix [4] [4]arene derivative and demonstrated that it was an excellent copper selective chemsensor.…”