Synthesis and characterization of some conjugated -ketoesters and their Cu(II) complexes

Abstract

Five conjugated -ketoesters (HL1 to HL5 ) with the keto group connected to carbon-carbon double bond have been prepared through the condensation of methyl acetoacetate with aromatic aldehydes (4-nitrobenzaldehyde; 4-methoxybenzaldehyde; 3,4-dihydroxybenzaldehyde; 3,4-dimethoxybenzaldehyde and indole-3-carbaldehyde). Structural characterization by physicochemical techniques indicated the occurrence of HL1 in the keto form and HL2 to HL5 in the intra-molecularly hydrogen bonded enol form. Details on the formation and nature of bonding in the [Cu(HL)(OAc)2] complex of HL1 and [CuL2] complexes of HL2 to HL5 are confirmed by analytical and spectral techniques.