Proton Ligand Formation Constants of 4-Hydroxy-5-Carboxy- 4'-Methoxy-Azo-Benzene and Formation Constants of Its Complexes with Cu(ll), Zn(ll), Ni(II) and Co(II)

School of Studies in Chemistry, Vikram University, Ujjain (M.P.)

Manuscript received 28 November 1975 ; accepted 30 March 1976

The proton-ligand formation constants of 4-hydroxy-5-carboxy-4'-methoxy-axo-benzene and formation constants of its complexes with Cu(II), Zn(II), Ni(II) and Co(II) have been determined by various computational methods. The order of stability (of log K₁) is found to be Cu(II)>Zn(II) >Ni(II)>Co(II). The results indicate chelation through 4-hydroxy and 5-carboxy groups of the salicylic residue.