Synthesis and characterization of piperazino-bis(methylantipyrine) and its complexes with chromium(III), manganese(II), cobalt(II), copper(II), zinc(II) and cadmium(II) ions

Abstract

A new Mannich base, piperazino-bis(methylantipyrine) (PBMA), was synthesized and characterized by spectral studies. Chelates of PBMA with chromium(III), manganese(II), cobalt(II), copper(II), zinc(II) and cadmium(II) ionswere prepared and characterized by elemental analyses and IR, UV and 1 H NMR spectral studies. PBMA was found to act as a hidentate ligand bonding through one of the carbonyl oxygens of antipyrine and one of the C-N-C groups of piperazine moiety. Based on the magnetic moment values and UV-Vis spectral data, trigonal bipyramidal geometry for chromium(III), distorted octahedral geometry for copper(II) chloro and bromo complexes and tetrahedral geometry for cobalt(II), zinc(ll) and cadmium(II) chloro and bromo complexes were assigned. TG and DTA studies show a double stage decomposition pattern for PBMA and its chromium(III), cobalt(II) and cadmium(ll) chloro complexes and a single stage decomposition pattern for zinc(II) hromo complex. The kinetic and thermodynamic parameters for the thermal decomposition of the metal chelates were evaluated using equations based on integral methods. The antimicrobial studies show that the zinc(II) complexes are more active than the other complexes.