Potentiometric and Theoretical Studies of Stability Constants of Glyoxime Derivatives and their Nickel, Copper,Cobalt and Zinc Complexes

摘要

The dissociation constants of l,2-bis(4-methylpiperazine)glyoxime (BMPGH2)and l,2-bis(4-benzylpiperazine)gly oxime (BBPGH2)were determined in 0.1 mol dm~(-3)NaCl and 0.001 mol dm~(-3)HC1 at 25 deg C potentiometrically.pK_a values of BMPGH2 and BBPGH2 were obtained as 2.91,6.79,7.97,10.00 and 3.46,5.89,6.77,9.76,respectively! The protonation order of nitrogen atoms in the BMPGH2 and BBPGH_2 were determined using Semi-empirical AMI method.In various pH conditions,the different complexes formulated as MH_6L_2,MH_5L_2,MH_4L_2,MH_3L_2,MH_2L_2,MHL_2,ML_2,MH_(-1)L_2,and MH_(-2)L_2 were formed with titration of ligand and Cu,Co,Ni and Zn ions.