Mechanisms of interstellar synthesis of glycine, alanine, and serine from aminonitriles, OH, and H2O

Abstract

AbstractA new potential energy surface for forming glycine in the gas phase, starting from association of aminoacetonitrile (NH2CH2CN) with OH followed by subsequent hydrolysis, was determined using CBS‐QB3 calculation. The overall activation energy was 90 kJ mol−1 or 0 without or with catalytic H2O, respectively. Alanine or serine was formed from 2‐aminopropionitrile (CH3CH(NH2)CN) or 2‐amino‐3‐hydrxypropionitrile (HOCH2CH(NH2)CN) instead of aminoacetonitrile with the overall activation energies of 89 or 49 kJ mol−1, respectively. When an additional H2O was involved in each reaction as a catalyst, barrierless reaction pathways were obtained. These results suggest that it is possible for investigated reactions to occur in interstellar ices along the proposed pathways, taking kinetic aspects into account.