Study of Proton-Ligand and Metal-Ligand Stability Constants of Some Substituted Isoxazolines

S. R. Dighade¹, M. L. Narwade²* and M .M. Chincholkar²*

¹Department of Chemistry, R.D.I.K. College,Badnera (India) 444701 ²Vidarbha Mahavidyalaya, Amravati (India) 444604

The interactions of Cu (II) and Ni (II) metal ions with I) 3-(2-hydroxy-5-methylphenyl)-4-benzoyl-5(3-nitrophenyl)-isoxazoline (Ligand No.1), ii) 3-(2-hydroxy-5-methylphenyl)-5(3-nitrophenyl)isoxazoline (Ligand No.2), iii) 3-(2-hydroxy-5-methylphenyl)-5-(4-methoxyphenyl)-isoxazoline (Ligand No.3) have been studied at 0.1 M ionic strength. It is observed that Cu(II) and Ni(II) metal ions from 1:1 and 1:2 complexes with L1,L2 and L3 (Substituted isoxazolines). The ligands L2 and L3 are more chelating agents than L1 synthesised from 3-aroylflavanone. The substituted isoxazolines show formation of stepwise complexes. The order of proton-ligand stability constant is as pk L3> pk L2> pk L1. The data obtained pK and logK are used i) to see the effect of substituents ii) to check the validity of logK = a pK + b. Here proton-ligand and metal-ligand stability constants have been studied pH-metrically by Calvin-Bjerrum titration technique.

Proton-ligand and metal ligand stability