Synthesis and characterization of divalent metal complexes with ligand derived from the reaction of 3-aminopyridine and biacetyl

Divalent cobalt, nickel and copper salts reacted in situ with 3-aminopyridine and biacetyl to form complexes of the type: [M(Ap2biac)2X2], where Ap2biac is the ligand and X=Cl, Br, NO3 or NCS. The complexes were analysed and characterized as distorted octahedral by conductance, molecular weight, magnetic, electronic and IR spectral studies. The electronic spectra were interpreted and tentative aassignments made. The infrared spectral studies revealed that two molecules of 3-aminopyridine were joined by molecules of biacetyl through a two carbon atom bridge and that the ligand coordinated through azomethine nitrogen atoms, whereas the pyridine nitrogen does not participate in the coordination. In the far infrared spectra, various metal–ligand vibrations were observed and are discussed.