Tetrazenes reaction mechanisms

The reaction between [Ir(Cl)(CO)(PPh3)2] and diazonium ions in the presence of ethanol or propan-2-ol affords the o-metallated diazene (112)276 and the iridium(III) tetrazene complex (113).277 A mechanism for the synthesis of (113) has been presented.278... 

The mechanism of nucleophilic amination presented by Eq. (73) seems very unlikely at first because of the instability of the azolyl cation and the low basicity of the N-amino group in Af-aminoazoles. However, the previously mentioned formation of arylazides from 1-aminobenzimidazole and aryldiazonium salts [Eq. (64)] is concerned, in fact, with such a process. Probably, the course of this reaction is governed also by the elimination of the azolyl fragment as the anion, which is due to the primary deprotonation of tetrazene 260. 

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