Synthesis of metal complexes of heteroatom bearing ligands and investigation of the effect of surfactant micelles on complexation

In this study, the ligands of bis(2-amino-1,3,4-thiadiazole) (L1), bis(2-amino-1,3,4- thiadiazolyl)methane (L2) and bis(2-amino-1,3,4-thiadiazolyl)benzene (L3) have been synthesized via the reactions of oxalic acid, malonic acid and terepthalic acid with thiosemicarbazide. The structures of L1, L2 and L3 compounds have been elucidated, by element and spectroscopic data analyses. Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes of L1 and L2; and Ni(II) and Cu(II) complexes of L3 have been synthesized; and the structures of these complexes have been determined by elemental analysis, spectrometric and TGA/DTA methods and by magnetic susceptibility and molar conductivity measurements. Coordination numbers of monomeric L2Ni, L3Ni. L1Cd, L3Cu, L1Ni, L2Zn, L2Cd complexes and the coordination numbers of dimeric L1Zn, L1Cu, L2Cu, L1Co, L2Co complexes are 4, 4, 4, 4, 6, 5, 6 and 4, 5, 5, 6, 6; respectively.Effects of surface active agents (YA) on the formation of Cu complexes of L2 and L3 ligands were also investigated. For this purpose, effects of normal micelles of sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB) and sodium bis(2-ethylhexyl)sulfosuccinate(AOT) in water and in dimethylformamide (DMF); and the effects of the reverse micelles of AOT in AOT/heptane/DMF and AOT/heptane/water systems have been studied. It has been observed that SDS and AOT micelles enhance the complex formation while CTAB micelles have an inhibitory effect. The enhancement in AOT reverse micelles has been larger than those in the presence of normal micelles and the highest complex yield has been attained in AOT/heptane/water system, at the hydration ratio of 15. Under this condition, practical complexation yields for L2Cu and L3Cu have been increased in ratios of 20 % and 18 %; respectively.Micellar effects observed on complexation has been evaluated in terms of micellar structure and charge; as well as the of ratios of micellar solvation and hydration.