The complexes of adenosine and organocobalamins with palladium (II)

The complexes of adenosine, methylcobalamin, adenosylcobalamin and the derivatives of adenosylcobalamin with tetrachloropalladate (II) are described. The compositions of the complexes were established by means of spectrophotometric titration. Depending on the structure of organocobalamins, three types of complexes with tetrachloropalladate (II) are formed. In the case of methylcobalamin, the palladium (II) is coordinated at the "lower" benzimidazole ligand. In adenosylcobalamin, palladium (II) coordinates the "upper" adenosyl ligand. The N-7-position in adenosine ligand and N-3-position in 5,6-dimethylbenzimidazolyribotide are the most probable coordination sites of palladium (II).