SYNTHESIS AND CHARACTERIZATION OF Cr(III), Mn(II), Co(II), Ni(II), Cu(II) AND Zn(II) COMPLEXES WITH NEW MANNICH BASE DERIVED FROM QUINOXALINE-2-ONE

New transition metal complexes of the type [M(L)2(H2O)2]Cl2, [Cr(L)2(H2O)Cl]Cl, [Ni(L)2]Cl2 and ZnLCl2 were constructed with the Mannich base, which was formed by condensation reaction of 3-ethyl-7-methyl-quinoxalin-2-one with piperidine in the presence of formaldehyde. The Mannich base and it’s complexes were characterized by elemental analysis, conductance measurements and infrared, ultraviolet visible and 1H, 13C nuclear magnetic resonance spectroscopy. Monomer structures were proposed from the spectral measurements, with a bi dentate form. The octahedral structure was proposed for all the prepared complexes whereas the zinc(II) complex assigned as tetrahedral geometry. However the diamagnetic properties and electronic spectra of nickel(II) complex revealed the square planer geometry.