Copper(II) Complexes of Acyldihydrazones

Abstract

Copper(II) complexes of disalicylaldimine oxamide (H₄A), malonamide (H₄B), succinamide (H₄C), glutaramide (H₄D), adipamide (H₄E), and phthalamide (H₄F) have been synthesized in aqueous-alcoholic media and characterized by elemental analyses, thermoanalytical data, decomposition temperature, magnetic moments, infrared and electronic and electron spin resonance spectral studies. All the complexes were found to have the compositions Cu₂(L)nH₂O (where H₄L = H₄A, H₄B, H₄C, H₄D, H₄E, and H₄F, n = 2 and 4). These complexes possess square pyramidal configuration except disalicylaldimine oxamido and phthalamido complexes which possess tetragonally distorted octahedral stereochemistry. All the complexes show sub-normal magnetic moments. The magnetic moments coupled with powder ESR spectra in the solid state at room temperature indicate strong metal-metal interaction. The infrared spectra reveal that the ligands react in the enol form as tetrabasic hexadentate ligands. On the basis of the magnitude of shift in μ(C-O) (phenolic) the effect of increasing length of methylene chains and phenyl group on the formation of bridge structure has been discussed.