Complex Formation of Nucleosides with HgCl₂ and CdCl₂

Abstract

Through the observation of chemical shifts in nuclear magnetic resonance spectra, formation constants of 1 : 1 metal complexes with nucleosides were found in dimethyl sulfoxide at room temperature. The complex formation constants of CdCl₂-adenine and CdCl₂-benzyladenine are 1.6-1.7 times larger than the values for the HgCl₂ complexes of adenine and benzyladenine. On the other hand, the formation constant of HgCl₂-6-mercaptopurine is larger than the value of CdCl₂-6-mercaptopurine. 6-Methylmercaptopurine did not complex with HgCl₂ or CdCl₂. In nucleosides, the complex formation constant with HgCl₂ is in the order of 4-thiouridine, cyclocytidine, and cytidine. The complex formation with HgCl₂ or CdCl₂ was not observed with nucleoside analogs prepared from 5, 6-diamino-1, 3-dimethyluracil with D-glucose or D-galactose.