The remarkably stable catenated hexa-nitrogen chain in bis(benzotriazene-4-one) is structurally, theoretically, and spectroscopically characterized to illustrate the durability of the central N-N bond in this hexaazo chain. The reactions of this species illustrate the potential of these nitrogen catenates for the preparation of other condensed heterocycles, such as bispyrazolones, by thermal nitrogen exclusion or by trapping the single ring-opened Dimroth intermediates. In these latter reactions, 2-naphtholate anion condenses with bis(benzotriazene-4-one) to trap and retain a zwitterionic diazonium intermediate as an isolated diazo product, whereas transition metals ring effect ring-extrusion of dinitrogen from the Dimroth intermediate to generate chelating σ-aryls. The catenated nitrogen species can be stabilized by incorporating strong formal sp(2)-sp(2) N-N σ bonds with orthogonal orientations. Extending these stabilization and activation principles may allow these types of nitrogen catenates to be useful synthons for other polyaza species.
Keywords: Dimroth rearrangement; azo compounds; catenation; nitrogen; ring opening.
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