Аннотация:The recent detection of benzonitrile (C6H5CN) in theinterstellar medium is one of the most fascinating discoveries in astrochemistry and molecular astrophysics. However, the mechanism of its formation in interstellar ices remains unclear. Here, we reportthe first evidence for the direct synthesis of benzonitrile through the radiation-induced transformations of an isolated C6H6···HCN complex in inert rigid media at cryogenic temperature (4.5 K), asmonitored by Fourier transform infrared (FTIR) spectroscopy. The complex was prepared in a solid krypton matrix and characterized by the experimentally observed complexation-induced shifts in the FTIRspectra on the basis of comparison with the results of ab initio calculations. The formation of benzonitrile was revealed through the observation of its three fundamentals and partially confirmed by experiments with deuterated benzene. Presumably, C6H5CN results from the dehydrogenation of complex excited states followed by prompt radical−radical recombination within the matrix cage. The proposed route may be relevant to the formation of C6H5CN both in the bulky astrophysical ices and on the surface of interstellar dust grains.
