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Radicals and Anions of Siloles and Germoles
Author(s) -
Reinhold Crispin R. W.,
Schmidtmann Marc,
Tumanskii Boris,
Müller Thomas
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202101415
Subject(s) - chemistry , radical , electron paramagnetic resonance , delocalized electron , potassium , trimethylsilyl , halide , silylation , photochemistry , medicinal chemistry , inorganic chemistry , crystallography , organic chemistry , catalysis , physics , nuclear magnetic resonance
The synthesis of persistent sila‐ and germacyclopentadienyl (silolyl‐ and germolyl‐) radicals by careful stoichiometric reduction of the corresponding halides with potassium is reported. The radicals were characterized by EPR spectroscopy and trapping reactions. The reduction of tris (trimethylsilyl)silyl‐substituted halides was successful while smaller substituents (i. e., t ‐Butyl, Ph) gave the corresponding dimers. The EPR spectroscopic parameter of the synthesized tetrolyl radicals indicate only small spin delocalization to the butadiene unit due to cross‐hyperconjugation. Silolyl‐ and germolyl anions are unavoidable byproducts and are isolated in the form of their potassium salts and characterized by X‐ray crystallography. The comparison of the molecular structures of two closely related potassium silolides provided an example for different coordination of the potassium cation to the silolyl anion (η 1 vs. η 5 coordination) that triggers the switch between delocalized and localized states.