[FES FES(2)] - A REDOX SYSTEM FOR THE ORIGIN OF LIFE - (SOME EXPERIMENTS ON THE PYRITE-HYPOTHESIS)/

The FeS/FeS2 redox system, whose importance is stressed in recent theo ries on the origin of life, has been tested experimentally. In this pa per it is demonstrated by thermodynamical calculations as well as by e xperiments, that cyclohexanone, which served as model compound, can be reduced by the aforementioned redox system. Reactions were carried ou t in methanol and DMF at 25-degrees-C and at 100-degrees-C. Besides pr oducts that were synthesised in both solvents, like cyclohexanethiol a nd dicyclohexyldisulphide, special compounds were obtained in methanol and in DMF, because of the involvement of the respective solvent in t he reaction. Yields of reduced compounds were lower in methanol owing to a compound that hindered the reduction (cyclohexylketal). With incr easing temperature and duration the amount of reduced compoinds increa sed. Further experiments have shown that 1,1-cyclohexanedithiol is lik ely to be a necessary intermediate for the reduced products. The exper iments give evidence to the 'pyrite hypothesis', which postulates that the FeS/FeS2 redox system was of importance for the origin of life.