A comparative study of the metal binding behavior of alanine based bis-thiourea isomers

Abstract

Two new symmetrical bis-thiourea, 2,2'-[((terephthaloylbis(azanediyl)bis(carbonothioyl) bis(azanediyl))dipropanoic acid] (1A) and 3,3'-[((terephthaloylbis(azanediyl)bis (carbonothioyl)bis(azanediyl)) dipropanoic acid] (1B) were synthesized by the reaction of terephthaloyl chloride with α- and β-alanine in good yields. Their binding properties were investigated with various metal cations using UV-Vis titration experiments. Both isomers exhibited effective binding with Ag+, Cu2+, Hg2+, Pb2+, Fe2+ and Fe3+ cations. However, in the presence of other cations, such as Na+, Ni2+, Co2+, Cd2+, Zn2+, Mn2+, Mg2+, Ca2+, Sn2+, Al3+, and anions tetrabutylammonium Cl- and H2PO4-, no interaction occurred. Both isomers displayed similar trends towards binding with metal cations.