THE PEROXY RADICAL AS HYDROGEN-BOND DONOR AND HYDROGEN-BOND ACCEPTOR - A MATRIX-ISOLATION STUDY

The interaction between the peroxy radical and water, hydrogen chlorid e, chlorine, and ammonia has been studied in argon matrixes. The perox y radical acts as a hydrogen bond donor toward ammonia and forms a str ong hydrogen bond to the ammonia nitrogen, significantly stronger than the corresponding water ammonia bond. Hydrogen chloride binds to the lone pair of the terminal oxygen of the peroxy radical, which in this case is a hydrogen bond acceptor. The complex shift of the hydrogen ch loride stretch indicates a slightly weaker hydrogen bond than in the h ydrogen chloride-water complex. The shift of the OH stretch of the com plexed peroxy radical suggests the presence of a weak hydrogen bond fr om the peroxy radical hydrogen to one of the lone pairs of the chlorin e atom of HCl. Water forms a cyclic complex with the peroxy radical, w ith both molecules donating and accepting hydrogen bonds. Both one wat er OH stretch and the OH stretch of the peroxy radical are strongly sh ifted in the complex. The results of this study suggest that the perox y radical is a significantly stronger acid than water and that it read ily accepts hydrogen bonds.