Role of trace metal ions in chemical evolution.  The case of free-radical reactions.
We have studied the effect of iron in the free-radical oligomerization of hydrogen cyanide and acetic acid, and found that iron(II) and iron(III) readily reduces or oxidizes free radicals, respectively.  The transient species produced by these reactions do not induce a chain oligomerization process and, therefore, they protect the solute molecules from degradation.  Analysis of the available kinetic data for the reactions of a variety of transition metal ions with free radicals indicate that transition metal ions behave similarly to iron.  Since Fe, Zn and Mo are essential to all living organisms, and there seems to be no apparent difference in chemical reactivity among transition metal ions towards free radicals, we suggest that these metal ions probably protected the biomolecules from degradation induced by free-radical reactions in the later stages of chemical evolution.
Navarro-González
R
R
Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México.
Ponnamperuma
C
C
D019342:Acetic Acid / Q000737:chemistry* / Q000528:radiation effects; D001546:Bentonite / Q000737:chemistry; D002384:Catalysis; D019418:Evolution, Chemical; D005292:Ferricyanides / Q000737:chemistry; D005295:Ferrocyanides / Q000737:chemistry; D005609:Free Radicals / Q000737:chemistry*; D005720:Gamma Rays; D006856:Hydrogen Cyanide / Q000737:chemistry* / Q000528:radiation effects; D007477:Ions; D007501:Iron / Q000737:chemistry*; D008982:Molybdenum / Q000737:chemistry; D014131:Trace Elements / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry
D005292:Ferricyanides; D005295:Ferrocyanides; D005609:Free Radicals; D007477:Ions; D014131:Trace Elements; D001546:Bentonite; C007931:hexacyanoferrate III; D006856:Hydrogen Cyanide; D008982:Molybdenum; D007501:Iron; C020354:hexacyanoferrate II; D015032:Zinc; D019342:Acetic Acid