The Substitutional Effects on the Carbonyl and Metal -Oxygen Stretching Frequencies of Some 4-Acyl Functional Derivatives of 1-Phenyl-3-Methyl -4- Acyl Pyrazol -5- ones and Thier Divalent Metal Chelates

Abstract

The divalent  metal complexes of Mg (II), Co (II), Cu (II) and Zn (II) ions with some 1-phenyl-3-methyl-4-acyl pyrazolone-5 have been synthesized and characterized by physical methods such as elemental analysis , U.V, and I.R spectral analyses. The corroborative evidences from elemental analysis and spectral data show that complexes are neutral dihydrated  bischelates  conforming to the general formula ML₂.2 H₂O , where  M= Mg²⁺,Co²⁺,Cu²⁺ and Zn²⁺ ions and L= anions of  the 4-acyl pyrazolone ligand. Infrared spectral assignments(4000 -  400cm?1) were made and interpretation  of the spectral data revealed that the stability of C=O bond increased while that of the M=O bond decreased with increase in the number of carbon atoms of the 4-acyl substituent.

Keywords:  Stretching frequencies, 4 – acylpyrazolon-5 ,divalent metal chelates.