Aroylthioureas: new organic ionophores for heavy-metal ion selective electrodes

Abstract

Thiourea derivatives (46 aroylthioureas) having different substituents close to the sulfur atom were synthesized and their ionophore potential in ion selective electrodes (ISEs) was examined. Structural considerations were taken into account based on the corresponding heavy-metal ISE parameters. As ionophores, some 1-furoyl-3-substituted thioureas (series 2) gave the best results in Pb(), Hg() and Cd() ISEs. The strong intramolecular hydrogen bond in series 2 allows ligand interaction only through the C᎐ ᎐ S group. Substituents on the furan and phenyl rings give rise to low solubility in the membrane plasticizer. 3-Alkyl substituted furoylthioureas improve solubility but enhance oxidative processes with chain length. New X-ray diffraction (XRD) structures and theoretical DFT calculations were considered in the analysis of the substituent influence on the selectivity of ISEs. These new ionophores have advantages because of their stability, simple synthesis and easy modification of the sulfur binding ability resulting from substitution.

Synthesis, X-ray crystal structure, thermal behavior and spectroscopic analysis of 1-(1-naphthoyl)-3-(halo-phenyl)-thioureas complemented with quantum chemical calculations

“…Finally, the m(C@S) stretching mode (thioamide band IV) of 1-acylthiourea compounds is found around in the 600-800 cm À1 range [3,4,59,60], but higher wavenumbers values (up to 1100 cm À1 ), are also reported [44,48]. These differences suggest that the m(C@S) stretching mode is very sensitive to the presence of an intermolecular interactions involving the C@S group [41], which originates an intense Raman dispersion due to the polarizability of the C@S bond [61].…”

Mesoporous silica functionalized with 1-furoyl thiourea urea for Hg(II) adsorption from aqueous media

“…Secondly, we have studied the applicability of these hybrid materials for removal of Hg(II) from aqueous solutions. As already reported, due to the presence of three heteroatoms (S, O, N) and accordingly several functional groups, thiourea derivatives (unsupported or grafted on silica) are able to complex Hg(II) or other metallic ions [24,[36][37][38][39][40], as well as to catalyse organic reactions [41,42].…”

Crystal structure of cis-copper(II) complex with N-(di-n-propylcarbamothioyl)cyclohexanecarboxamide ligand

“…These ligand systems of thioureas are attractive scaffolds for several reasons (I) potential applications in a wide range of fields are being investigated and (II) these compounds are easily synthesized in high yields. Many acyl thiourea derivatives are well known as collectors in froth flotation processes [2,3] and as ionophores in ion-selective electrodes [4][5][6]. At the same time some of them are display a wide range of biological activity including insecticidal, herbicidal, antibacterial, antifungal, antitubercular, antithroid, antihelmintic, rodenticidal and plant-growth regulator properties [7][8][9][10].…”