MOLECULAR-COMPLEXES OF NITRIC-ACID WITH VARIOUS BASES STUDIED BY MATRIX-ISOLATION INFRARED-SPECTROSCOPY

The interaction of nitric acid with a number of bases has been investigated by infrared spectroscopy in low-temperature matrices (principally argon). The spectra show that nitrogen interacts strongly and specifically with nitric acid in argon matrices. Carbon monoxide behaves in a similar manner to nitrogen, forming complexes with the structure O=C C...H-ONO2. With water and dimethyl ether, hydrogen-bonded complexes of the type R2O...H-ONO2 were formed, and with ammonia a similar complex H3N...H-ONO2 was apparent. The strength of interaction, as evidenced by the shifts in the O-H vibrational modes of the nitric acid, increased from nitrogen, through carbon monoxide, water and dimethyl ether, to ammonia.