Studies in influence of ionic strength of medium on the complex equilibria of substituted hydroxy-1,3-popandiones with CIII and LaIII metal ions pH metrically

R.D.I.K. & N.K.D. CoiJege, Badnera (Riy.), Amravati-444 701, Maharashtra, India

E-mail : sdthakur1968@indiatimes.com

S.P.M. College, Ghatanji, Dist. Yavatmal, Maharashtra, India

Manuscript received 26 September 2011, revised 30 January 2012, accepted 31 January 2012

The solution studies (the proton-ligand stability constant pK and metal-ligand stability constants log K) of binary (1 : 1) complexes or Cr^Ill and La^llI with 1-(2'-hydroxy-S'-bromophenyl)-3-(2'-chlorophenyl)-1,3-propanedione [HB2CP] [L₁] and 1-(2'-hydroxy-S'-bromophenyl), 3-(4'-nilrophenyl)-1,3-propanedione [HB4NP] [L₂] have been performed at 0.02 to 0.1 mol dm^-3 ionic strength at (29 ± 0.1 °C) in 70% dioxane-water mixture pH-metrically. The pK and log K values are utilized to estimate the thermodynamic stability constants at zero ionic strength and to know the exact nature or complexation equilibria.