Chiral molecules in space and their possible passage to planetary bodies recorded by meteorites
Sandra Pizzarello, Christopher T. Yarnes
Earth and Planetary Science Letters
Volume 496, 15 August 2018, Pages 198–205
• Murchison extracts were found to contain two close derivatives of Propylene Oxide.
• Both are chiral and show (R)(+) variable enantiomer excesses averaging of ∼10%∼10%.
• Their hydrolysis produced Propylene Glycol, its homologues and polymeric materials.
• These hydrolytic products showed δD (‰) of +235 and +65, respectively.”
“We searched the ethanol extracts of the Murchison meteorite for propylene oxide (PrOx), the only chiral molecule discovered so far outside solar environments, and detected its likely derivative after isolation of the low boiling components of the extract. This compound is also chiral and, upon hydrolysis, produces propylene glycol (PrGl), the expected product of PrOx under these conditions. Both the PrOx derivative and PrGl were detected with variable enantiomeric excesses (ee) averaging at ∼10% and to have the (R)(+) configuration, i.e., for the same optical isomer as for sugars in the biosphere and sugar derivatives in meteorites. Besides PrGl, the hydrolysates also contained homologous compounds and polymeric materials with the combined δD (‰) of +235 and +65, respectively, suggesting a yet unknown compositional complexity in meteorites. The occurrence of ee in interstellar PrOx cannot be ascertained with current spectroscopic methodologies, however, the overall data reported here would allow to imply it.