Direct Evidence For A Radiation-Induced Synthesis Of Acetonitrile And Isoacetonitrile From A 1: 1 Ch4midline Horizontal Ellipsishcn Complex At Cryogenic Temperatures: Is It A Missing Link Between Inorganic And Prebiotic Astrochemistry?

Nitriles are important constituents of extraterrestrial media. Nitriles are supposed to play a crucial role in prebiotic chemistry occurring in the interstellar medium. In this work, we have investigated the low-temperature radiation-induced transformations of a 1 : 1 CH4MIDLINE HORIZONTAL ELLIPSISHCN complex as a plausible precursor of the simplest nitriles using the matrix isolation approach with FTIR spectroscopic detection. The parent complexes isolated in a noble gas (Ng) matrix were obtained by deposition of the CH4/HCN/Ng gaseous mixture and characterized by comparison of experimental complexation-induced shifts of the HCN fundamentals with the results of the ab initio calculations. It was found that the X-ray irradiation of low-temperature matrices containing the isolated 1 : 1 CH4MIDLINE HORIZONTAL ELLIPSISHCN complex resulted in the formation of acetonitrile (CH3CN) and isoacetonitrile (CH3NC) and it appears to be the first experimental evidence for the formation of C-2 nitriles (acetonitrile and isoacetonitrile) from such a "building block". Additionally, a 1 : 1 CH4MIDLINE HORIZONTAL ELLIPSISHNC complex was tentatively assigned to the irradiated Ar and Kr matrices. It is demonstrated that the matrix has a strong effect on the CH3CN/CH3NC yield ratio, which dramatically increases in the row Ar < Kr < Xe. Also, the efficiency of the radiation-induced formation of the CH4MIDLINE HORIZONTAL ELLIPSISHNC complex was shown to decrease from Ar to Kr. It is believed that the proposed pathway for acetonitrile formation may be a significant step in the radiation-induced evolution leading to complex organic molecules and biomolecules under astrochemical conditions. Furthermore, the obtained results provide a prominent example of the impact of very weak intermolecular interactions on the radiation-induced transformations in cold media.