A Germapyramidane Switches Between 3D Cluster and 2D Cyclic Structures in Single‐Electron Steps.

Coburger, Peter; Masero, Fabio; Bösken, Jonas; Mougel, Victor; Grützmacher, Hansjörg

Reaction of the imidazolium‐substituted iphosphate‐diide, (Ipr)2C2P2 (IDP), with GeCl2 ⋅ dioxane and KBArF24 [(BarF24)−=tetrakis[(3,5‐trifluoromethyl)phenyl]borate)] afforded the dicationic spherical‐aromatic nido‐cluster [Ge(η4‐IDP)]2 ([1]2 ) (Ipr=1,3‐bis(2,6‐diisopropylphenyl)imidazolium‐2‐ylidene). This complex is a rare heavy analogue of the elusive pyramidane [C(η4‐C4H4)]. [1]2 undergoes two reversible one‐electron reductions, which yield the radical cation [2]⋅ and the neutral GeII species 3. Both [2]⋅ and 3 rearrange in solution forming the 2D aromatic and planar imidazolium‐substituted digermolide [4]2 and germole‐diide 5, respectively. Both planar species can be oxidized back to [1]2 using AgSbF6. These redox‐isomerizations correspond to the fundamental transformation of a 3D aromatic cluster into a 2D aromatic ring compound upon reduction and vice versa. The mechanism of these reactions was elucidated using DFT calculations and cyclic voltammetry experiments.

RADICAL cations; CYCLIC compounds; CYCLIC voltammetry; AROMATIC compounds; DIOXANE

Angewandte Chemie, 2022, Vol 134, Issue 47, p1

0044-8249

Academic Journal

10.1002/ange.202211749