Molecular complexes of nitric acid with N2, CO and NO studied by matrix isolation IR spectroscopy

Abstract

The interaction of nitric acid with dinitrogen, carbon monoxide and nitric oxide has been investigated by IR spectroscopy in low-temperature argon matrices. The spectra show that under these conditions N₂ interacts strongly and specifically with HNO₃, forming several distinct 1:1 complexes. The probable structures of these complexes are discussed. CO behaves in a similar manner to N₂, forming complexes of the type OC⋯H—ONO₂; weak bands due to a CO⋯H—ONO₂ complex were generated by photolysis. For NO, complexes of HNO₃ were observed with both monomeric and dimeric NO. The strength of interaction with HNO₃ was found to increase in the order N₂ < NO < CO.