The interaction of ribonucleotides with metal hexacyanochromates(III) and the relevance to chemical evolution

The interaction of ribonucleotides, namely 5'-AMP, 5'-GMP, 5'-CMP, and 5'-UMP, with cobalt(II) and cadmium(11) hexacyanochromates(III) has been studied. Maximum adsorption was observed at a neutral pH. Adsorption isotherms were found to be Langmuirian in nature. Values for Xm and KL were calculated. Purine nucleotides showed more adsorption than pyrimidine nucleotides on both the metal hex acyanochromates(III), whereas cobalt(II) hexacyanochromate(III) was found to be a better adsorbent for all of the ribonucleotides studied. Infrared spectral studies of the adsorption adducts suggested that adsorption occurs due to interactions between the phosphate moiety and base residue of the ribonucleotide molecule with outer divalent metal ions present in the lattice of metal hexacyanochromates(III). The results of the present study support the hypothesis that metal cyanogen complexes might play an important role in concentrating and stabilizing the biomonomers on their surfaces through adsorption processes during the course of chemical evolution.