Complex formation of adenine and 9‐methyladenine with transition metal salts in ethanol

Abstract

AbstractThe coordination chemistry of adenine and 9‐methyladenine towards transition‐metal ions has been studied. Solid compounds of the formula M(AH)2X2 were isolated and characterised for M = Ni, Cu, Zn and Cd and X = Cl, Br, NO3 and ClO4; AH standing for adenine. With 9‐methyladenine (MA) solid compounds formulated as M(MA)X2(M = Co, Ni, Cu, Zn and Cd; X = Cl and Br) and formula M(MA)2(NO3)2‐nH2O (M = Co and Ni with n = 2 and M = Cu, with n = 1) have been synthesized.The compounds were characterised by chemical analysis, infrared spectra, far‐infrared spectra, ligand‐field spectra, X‐ray powder diagrams, ESR powder spectra and magnetic susceptibility measurements. Despite several attempts, no compounds containing more than two of these ligands per metal ion could be òbtained. Extensive ligand‐ligand and ligand‐anion hydrogen bonding may account for this result.With a few exceptions adenine appears to coordinate via N(9) in monomeric compounds and via N(3) and N(9) in dinuclear compounds. The respective coordination sites in 9‐methyladenine complexes are N(7) in the case of monodentate coordination, and N(1) and N(7) in the case of bidentate bridging coordination.