Abstract: There is an increasing interest for the study of NO affinity of organic nitrite, for the biological and physiological effects of organic nitrites seem to be due to their ability releasing NO. In this paper, NO chemical affinities of ten benzyl nitrites were determined respectively by titration calorimetry and from a thermodynamic cycle in acetonitrile solution. The results show that ΔH_het of O—NO in the O-nitroso compounds were substantially larger than the corresponding ΔH_homo of O—NO in the same compounds, suggesting that these O-nitroso compounds were much easier release NO radical by the O—NO bond homolytic cleavage. It is believed that the structural and energetic information disclosed in this work should be useful in understanding chemical and biological functions of organic nitrites.

Key words: Benzyl nitrite, Chemical affinity, O—NO bond energy, Titration calorimetry