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

The coupling of diazotized 2-aminothiazole and 2-aminobenzo-thiazole with cyclohexane-1,3-dione yielded a new type of tridentate ligand systems (HL). Analytical, IR, 1H NMR, 13C 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)] has been established on the basis of analytical and spectral data. The Zn(II) chelates are diamagnetic while Cu(II) and Ni(II) complexes showed normal paramagnetic moment

Unsaturated b-ketoesters and their Ni(II), Cu(II) and Zn(II) complexes

A new series of b-ketoesters in which the keto group is attached to the olefinic linkage were synthesized by the reaction of methyl acetoacetate and aromatic aldehydes under specified conditions. The existence of these compounds predominantly in the intramolecularly hydrogen bonded enol form was well demonstrated from their IR, 1H-NMR and mass spectral data. Details on the formation of their [ML2] complexes with Ni(II), Cu(II) and Zn(II) and the nature of the bonding are discussed on the basis of analytical and spectral data