Progress in the tautomerism and decomposition of amino-tetrazoles

The tautomerization and decomposition channels of amino-tetrazoles, mainly 5-amino-tetrzole and 1,5-diamino-tetrzole, were reviewed. The up-to-date study shows that 1-substitute-amino-tetrazoles, 2-substitute-amino-tetrazole and 1-substitute-imino-tetrazoles are the most common isomers of amino-tetrazoles. There are basically two mechanisms for the decomposition of amino-tetrazoles. In the first mechanism the two bonds of the tetrazole ring break off, resulting in RN₃ and NH₂CN. The second decomposition channel comprises two steps. Firstly the N-N bond is cleaved, leading to RN₃. Then the produced RN₃ loses one molecule N₂. In this paper,the tautomerization mechanisms of amino-tetrazoles represented by 5-amino-tetrazole and 1,5-diamino-tetrazole were investigated by using high level quantum chemistry calculations, the results show that the active energy of the first decomposition path way is lower than that of other paths, so it is the most probable reaction path.