The gamma-irradiation of aqueous hydrogen cyanide in the presence of ferrocyanide or ferricyanide: implications to prebiotic chemistry.

The gamma-irradiation of 0.1 M, O2-free, aqueous HCN was studied in the presence of ferrocyanide or ferricyanide in the concentration range 10(-3) - 10(-5) M. This study was carried out in order to get an insight into the possible role that cyanocomplexes of iron may have played in promoting prebiotic syntheses via the free-radical oligomerization of HCN. It was found that ferrocyanide or ferricyanide have no effect on the irradiation of 0.1 M HCN solutions at concentrations < or = 10(-4) M. At high concentrations, 10(-3) M, they lead to a marked decrease in the conversion of HCN. There was no significant difference due to the oxidation state of iron used, particularly at high doses > or = 100 kGy.