Bis(silylene)‐Stabilized Monovalent Nitrogen Complexes

Abstract

The first series of bis(silylene)‐stabilized nitrogen(I) compounds is described. Starting from the 1,2‐bis(N‐heterocyclic silylenyl) 1,2‐dicarba‐closo‐dedocaborane(12) scaffold 1, [1,2‐(LSi) ₂C ₂B ₁₀H ₁₀; L=PhC(N ^tBu) ₂], reaction with adamantyl azide (AdN ₃) affords the terminal N‐μ ₂‐bridged zwitterionic carborane‐1,2‐bis(silylium) AdN ₃ adduct 2 with an open‐cage dianionic nido‐C ₂B ₁₀ cluster core. Remarkably, upon one‐electron reduction of 2 with C ₈K and liberation of N ₂ and adamantane, the two silylene subunits are regenerated to furnish the isolable bis(silylene)‐stabilized N ^I complex as an anion of 3 with the nido‐C ₂B ₁₀ cluster cage. On the other hand, one‐electron oxidation of 2 with silver(I) yields the monocationic bis(silylene) N ^I complex 4 with the closo‐C ₂B ₁₀ cluster core. Moreover, the corresponding neutral N ^I radical complex 5 results from single‐electron transfer from 3 to 4.

Abstract

Starting from the unusual end‐on neutral bis(silylium) nido‐carborane N ₃Ad adduct 1, one‐electron reduction with KC ₈ in the presence of 18‐c‐6 leads to the K(18‐C‐6) salt 2 with the first anionic N ^I complex and a bis(silylenyl) nido‐carborane ligand scaffold. One‐electron oxidation of 1 with silver(I) affords the cationic N ^I complex 3, which features a bis(silylenyl) closo‐carborane ligand. Ad=adamantyl; 18‐C‐6=18‐crown‐6.