Metal Complexation with Adenine and Thymine

Abstract

Metal complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with adenine and thymine were synthesized from aqueous ethanol solutions at ∼ pH 7. The new complexes involve 2:1:1 metal to adenine to thymine molar ratios. The complexes are polymeric in nature involving adenine as well as hydroxyl group bridges between metal ions and hydrogen bonds between adenine and thymine molecules. Spectral studies suggest that adenine is coordinated to metal ions through the N(3) and N(7) nitrogens whereas thymine is coordinated through the C₍₂₎ = O group. All the metal ions are in the hexa-coordinate state in the complexes. Powder X-ray diffraction studies indicate ortho-rhombic symmetry for Co(II)-ADN-THY and Cu(II)-ADN-THY complexes.