Role of sulfur in proton-induced collisions of RNA prebiotic precursors.

A main objective in the synthesis of prebiotic compounds is to remain consistent with reasonable geochemical scenarios, while avoiding concomitant formation of undesirable by-products. In this context, 2-aminothiazole has shown enhanced selectivity in the addition reaction with sugars promoting interest in this sulfur species compared to its oxygenated analogue, 2-aminooxazole. More generally, the role of sulfur in prebiotic chemistry needs to be widely investigated with regard to the numerous sulfur-containing molecules detected recently in different astrophysical environments. However, in parallel to the problematic formation of building blocks of life, how prebiotic molecules could survive under extreme astrophysical conditions remains an open question. Intense UV radiation or ion bombardment may indeed lead to fragmentation and the specific behaviour of sulfur compounds has to be addressed. Focusing on its potentiality in prebiotic multistep synthesis, a detailed analysis of the proton impact on 2-aminothiazole has been investigated theoretically in a wide collision energy range chosen to model various astrophysical environments. The comparison with its oxygenated analogue may suggest qualitative trends on their respective stability under such processes which could be of crucial interest for prebiotic synthesis.