Structures and Physicochehical Properties of Some Azo Complexes

Abstract

The interaction of 2-carhoxyphenylazo-β-naphthylmine (CPANA, HL), 2,4-dihgdroxyphenylazo-2-hydroxybenzene (DPAHB, H₃L) and 1-(2-pyridylazo)-2-naphthol(PAN, HL), with cobalt, nickel and copper salts was investigated. CPANA gave CoL₂.2H₂O, Ni(L)Cl.H₂O and CuLCl complexes while DPAIB formed CO(H₂L)₂.4H₂O, Ni(H₂L).3H₂O, Cu(H₂L)Cl.H₂O and Cu(HL)H₂O complexes and those with PAN were MLCL-XH₂O (M[dbnd]Co, X[dbnd]2; M[dbnd]Ni, X[dbnd]l and M[dbnd]Cu, X[dbnd]0). Potentiometric and conductometric studies proved that the mechanisn of complexation was based on hydrogen ion libezation. Log β valies for copper complexes were 4.0 for CPAXA, 13.0 for DPAHB and 7.5 and 10.9 for PAN systems. The cobalt complexes and Ni(II)-DPAHB complex are of octahedral geometry. The Ni(II)-PAH, Ni(II)-CPANA and all copper complexes are of square planar stcreochenistry. The spectra data depict that DPHB and PAN complexes were predominating in the hydrazone structure rather than the azo.