Potentiometric Studies on the Complexes of Some Divalent Metal Ions and Rare Earth Metal Ions with 3-Methyl-2-thio-2,4( 1H, 3H)-quinazolinedione

Physical Chemistry Laboratory, Institute of Science, Bombay-400 032
Manuscript received 19 July 1983, revised 16 December 1983, accepted 3 May 1984

Potentiometric studies have been carried out on 3-methyl-2-thio-2,4(1H,3H)-quinazolinedione
as ligand for complexation with divalent metal ions like Zn^II, Cd^II,Ni^II, Mn^II and some rare earth metal ions like Nd^III, Sm^III, Gd^III, Dy^III, The proton-ligand and metal-ligand stability constants have been determined by Bjerrum's eng

method at 27 ± 1^o and at ionic strength 0.1 M in 3 : 1 (v /v) dioxan-water medium. The order or stability constants observed is In agreement with the order reported by previousworkers. In cue or rare earth metal ions the stability constants are higher as comparedto the divalent metal ions studied, thereby indicating more ionic character.