Prebiotic polymerization:  oxidative polymerization of 2,3-dimercapto-1-propanol on the surface of iron(III) hydroxide oxide.
The oxidation of 2,3-dimercapto-1-propanol by ferric ions on the surface of iron(III) hydroxide oxide (Fe(OH)O) yielded polydisulfide oligomers.  This polymerization occurred readily at low dithiol concentration under mild aqueous conditions.  Polydisulfide polymers up to the 15-mer were synthesized from 1 mM dithiol in 5 ml water reacted with iron(III) hydroxide oxide (20 mg, 160 micromoles Fe) for 3 days under anaerobic conditions at 40 degrees C and pH 4.  About 91% of the dithiol was converted to short soluble oligomers and 9% to insoluble larger oligomers that were isolated with the Fe(OH)O phase.  Reactions carried out at the same ratio of dithiol to Fe(OH)O but at higher dithiol concentrations gave higher yields of the larger insoluble oligomers.  The relationship of these results to prebiotic polymer synthesis is discussed.
Weber
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SETI Institute, NASA Ames Research Center, Moffett Field, CA 94035-1000, USA.
D004112:Dimercaprol / Q000737:chemistry*; D004220:Disulfides / Q000138:chemical synthesis*; D019418:Evolution, Chemical; D005290:Ferric Compounds / Q000737:chemistry*; D008956:Models, Chemical; D000069497:Origin of Life; D010084:Oxidation-Reduction; D010777:Photochemistry; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D013997:Time Factors; D014050:Toluene / Q000031:analogs & derivatives* / Q000737:chemistry; D014867:Water
D004220:Disulfides; D005290:Ferric Compounds; D011108:Polymers; D014867:Water; D004112:Dimercaprol; C021024:ferric hydroxide; D014050:Toluene; C004848:dithiol