Singlet carbenes as mimics for transition metals: synthesis of an air stable organic mixed valence compound [M2(C2)+˙; M = cyclic(alkyl)(amino)carbene]

Abstract

A cyclic C-bromo-iminium bromide reacts with lithium trimethylsilyl acetylide to afford the title compound 2⁺˙ in 40% yield. In contrast to other organic mixed valence compounds, this radical cation can be stored in air. Oxidation and reduction of 2⁺˙ afford the corresponding dication 2⁺⁺ and neutral cumulene 2, respectively, in good yields.