Crystalline <scp>Germanium‐Dipyrromethene</scp> Radicals: from a Delocalized Neutral to a Localized Cation
Yuyang Dai, Manling Bao, Wenjuan Wang, Zhuofeng Xie, Chunmeng Liu, Yuanting Su
Abstract
Comprehensive Summary Both dipyrromethene complexes and radicals of heavier main group elements have been of high interest. However, cationic germanium radicals and dipyrromethene‐based radicals of heavier main group elements are still escaped to be isolated. Herein, we report the isolation and full characterization of a neutral Ge(I)‐masked dipyrromethene‐based radical 3 and the first cationic Ge(III)‐centered radical 5 ·+ as stable crystalline solids. 3 behaves as a germanium(I) radical in its reaction with diphenyl disulfide to form the Ge—S bond, although X‐ray crystallographic, EPR spectroscopic, computational studies revealed that the unpaired electron of 3 is mainly delocalized over the C 9 N 2 Ge backbone and the allylic radical character is also significant in 3. In contrast to 3, the spin density of 5 ·+ is mainly localized at the Ge center with minor contribution from the dipyrromethene ligand. Moreover, reduction of 5 ·+ with potassium graphite quantitatively regenerates 5, illustrating a reversible one‐electron redox pair.