Spectroscopic studies on Co(II) and Cu(II) complexes of 6-amino-1-methyl-5-nitrosouracil and its 6-methylamine derivative

Four complexes are obtained during the reactions of 6-amino-1-methyl-5-nitrosouracil and its 6-methylamine derivative with Co(II) and Cu(II) ions. Theses complexes were characterized through their elemental, thermal analysis, infrared and H-1 NMR spectroscopes. The obtained results indicate that, the exocyclic oxygen and nitrogen atoms are the most probable binding sites rather than ring nitrogen atoms. For cobalt complexes, the two pyrimidine bases act as bidentate ligands in the anionic form with the dissociation of iminic or N(3) proton depending upon the nature of substituents on the pyrimidine ring. For copper complexes, the pyrimidine bases interact in the neutral form as monodentate ligands. Octahedral geometries are proposed for all of these complexes. (C) 2004 Elsevier B.V. All rights reserved.