Synthesis and spectral characterization of zinc(II), copper(II), nickel(II) and manganese(II) complexes derived from bis(2-hydroxy-1-naphthaldehyde) malonoyldihydrazone

The present study shows that the reaction of different salts of the same metal with sterically crowded dihydrazone bis(2-hydroxy-1-naphthaldehyde) malonoyldihydrazone (CH2LH4) in ethanol/aqueous media gives complexes of different stereochemistry. While the reaction of zinc( II) and copper(II) sulphate with dihydrazone yields tetrahedral complexes, the zinc( II) and copper( II) chlorides give square pyramidal and distorted octahedral complexes, respectively. On the other hand, nickel(II) sulphate and chloride, both give high-spin octahedral complexes with dihydrazone, manganese sulphate gives low-spin octahedral and manganese(II) chloride gives high-spin octahedral complexes. The reaction of these complexes with KF has been investigated. All of the products have been characterized by analytical, magnetic moment and molar conductivity data. The structures of the complexes have been established by spectroscopic studies.