Synthesis and Structural Investigation of Some Transition Metal Complexes Derived from Assembled NO Donor Lewis Base of 6,7-Dimethyl-Quinoxaline-2,3-dione

Abstract

The synthesis of a new ligand (Z)-3-((2-aminoethyl)imino)-6,7-dimethyl-3,4-dihydroquinoxalin-2(1H)-one containing quinoxaline and aliphatic ethylene moiety subunits is described. The reaction of 6,7-dimethylquinoxaline-2,3(1H,4H)-dione with ethylenediamine in glacial acetic acid as catalyst leads to the isolation of the free ligand (L), which is a Lewis base precursor. The new transition metal complexes of (L) ligand were prepared and characterized by elemental analysis and spectroanalytical techniques. The new poly dentate L Schiff base was formed up on condensation of 6,7-dimethylquinoxaline-2,3(1H,4H)-dione with ethylenediamine in glacial acetic acid as catalyst. The free ligand was fully identified with the help of elemental analyses, mass spectra,H NMR and FTIR spectra. The direct reactions of methanolic ligand (L) with the salts of manganese(II),cobalt(II),nickel(II),copper(II),zinc(II),cadmium(II) and vanadium(IV) resulted in colored precipitated which have been characterized by elemental analyses, magnetic susceptibility, molar conductivity measurements and FTIR and UV-Visible spectroscopy. The metal to ligand ratios data concluded that all structures of complexes were in 1:1 ratio with octahedral geometry for all complexes except that nickel(II) was square planner The compounds were characterized by physical and spectroscopic measurements which indicated that the ligand is probably acting as a tridentate ON2 chelating agent.