A Germapyramidane Switches Between 3D Cluster and 2D Cyclic Structures in Single‐Electron Steps
Peter Coburger, Fabio Masero, Jonas Bösken, Victor Mougel, Hansjörg Grützmacher
Abstract
Abstract Reaction of the imidazolium‐substituted iphosphate‐diide, (Ipr) 2 C 2 P 2 ( IDP ), with GeCl 2 ⋅ dioxane and KBArF 24 [(BarF 24 ) − =tetrakis[(3,5‐trifluoromethyl)phenyl]borate)] afforded the dicationic spherical‐aromatic nido ‐cluster [Ge(η 4 ‐ 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(η 4 ‐C 4 H 4 )]. [ 1 ] 2+ undergoes two reversible one‐electron reductions, which yield the radical cation [ 2 ]⋅ + and the neutral Ge II 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 AgSbF 6 . 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.