Relation between structure and the degree of hydration for cobalt(II) bonded to nucleoside 5′-monophosphates

Abstract

The variation of coordination geometry with degree of hydration has been studied for cobalt(II) bonded to 5′-AMP, 5′-GMP, 5′-IMP, 5′-UMP, and 5′-CMP. Pink compounds with octahedral coordination about the metal ions were isolated but partial dehydration results in conversion to blue compounds containing tetrahedral cobalt. The ease of conversion is markedly dependent on the identity of the nucleotide. In the case of Co II-5′-AMP warming in water at 34°C is sufficient to cause the change to the tetrahedral form. Spectral results are given and some possible implications to the behaviour of cobalt-containing metalloenzymes, such as Co-RNA polymerase from E. coli, are briefly discussed.