Infra-Red Assisted Synthesis of Prebiotic Glycine

In the present study, we have shown for the first time how glycine can be synthesized under prebiotic-like conditions using an Infra-Red laser to trigger the reaction. In particular, we observed that in the low-density conditions it can be obtained from simple ion-molecule reactions of acetic acid and protonated hydroxylamine. This reaction, studied years ago in more dense conditions [J. Am. Chem. Soc. 2007, 129, 9910-9917R], was the center of a controversy, since accurate quantum chemistry calculations have shown that it is not barrierless [Astrophys. J. 2012, 748, 99] such that a source of energy is needed. In space, and more in general in prebiotic conditions (interstellar medium, comets, asteroids) temperature is very low but the photon density can be important. Here we propose a way of synthesizing such complex organic molecule in a very low-pressure environment (about 10^-3 mbar). This way of forming complex organic molecule is of relevance also beyond the prebiotic interest of finding a scenario which was at the origin of the synthesis of such molecules. In fact our work proposes a new way of assisting reactions using IR radiation. Only few cases were found in which IR can trigger complex reactions (i.e. not simple dissociations) while there is a clear interest of using such low-energy radiation. This study will be at the basis of new researches devoted to find other reactions which can be assisted by IR laser.