Persistent and Predominantly Localized Boron Radical from the Reduction of a Three‐Dimensional Analogue of NHC‐Stabilized Borafluorenium

Abstract

In this contribution, we reported the three-dimensional (3D) analogues of N-heterocyclic carbene (NHC)stabilized 9-borafluorenium and 9-borafluorene radical. The radical was fully characterized by cyclic voltammetry (CV), UV-Vis absorption spectroscopy, electron paramagnetic reso-nance (EPR) and single-crystal X-ray diffraction analyses. The distinct boron-centered radical character of 9-borafluorene radical was corroborated by DFT calculations and EPR analysis.

Reactivity study of Lewis superacidic carborane-based analogue of 9-bromo-9-borafluorene towards Lewis bases

“…4 b Moreover, the chloro derivative reacts with N-heterocyclic carbenes (NHCs), resulting in the formation of either an NHC adduct (Fig. 1b, middle), 8 or an NHC-stabilized 3D 9-borafluorenium cation. 8 Additionally, the first 3D 9-borafluorene radical could be attained upon single-electron reduction of the 3D 9-borafluorenium cation (Fig.…”

Avenue to novel o-carboranyl boron compounds – reactivity study of o-carborane-fused aminoborirane towards organic azides

“…9 Additionally, owing to the unique hyperconjugation between carborane cluster and outer-cage groups, 10–12 the 3D carborane cages hold substantial promise in replacing conventional 2D aromatic aryl groups for the construction of optoelectronic materials. 3,13–16 However, despite these intriguing aspects, research on carboranyl boranes is still relatively lagging compared to traditional organoboranes.…”

Full Electron Delocalization across the Cluster in 1,12-bisBMes2-p-carborane Radical Anion

“…This would allow electron delocalization through the cluster and make it potentially useful for constructing conjugated materials. However, both experimental and theoretical studies show weak communication between 2D π-systems and 3D carborane cages. − Hawthorne, Low, and co-workers reported complexes 1 – 3 (Scheme ) with two metal centers separated by p -carborane and concluded that the coupling between the metal centers is weak. − Further studies on the photophysics of dicarbazole-substituted m - and p -carboranes indicate that m - and p -carboranes are insulators that completely separate the two carbazole electronic systems. , …”