Heteroarylazo derivatives of cyclohexane-1,3-dione and their metal complexes

The coupling of diazotized 2-aminothiazole and 2-aminobenzothiazole with cyclohexane-1,3-dione yielded a new type of tridentate ligand system (HL). Analytical, IR, H-1-NMR, C-13-NMR and mass spectral data indicate the existence of the compounds in the intramolecularly hydrogen bonded azo-enol tautomeric form. Monobasic tridentate coordination of the compounds in their [CuL(OAc)] and [ML2)] complexes [M = Ni(II) and Zn(II)] was established based on the analytical and spectral data. The Zn(II) chelates are diamagnetic while the Cu(II) and Ni(II) complexes showed a normal paramagnetic moment.