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Oligomerization of N‐Heterocyclic Silylene into Zwitterionic Silenes
Author(s) -
Zabula Alexander V.,
Guzei Ilia A.,
West Robert,
Li Jingbai,
Rogachev Andrey Yu.
Publication year - 2016
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201606915
Subject(s) - silylene , diradical , carbene , singlet state , germanium , chemistry , atom (system on chip) , double bond , photochemistry , crystallography , computational chemistry , silicon , catalysis , organic chemistry , physics , atomic physics , computer science , embedded system , excited state
N‐Heterocyclic carbenes (NHC's) are known to serve as efficient substrates for the stabilization of various transient species possessing low‐valent Group 14 elements and for the generation of double E=C bonds. Herein, we report that the thermal tri‐ and tetramerizations of pyridoannulated silylene 1 lead to the formation of remarkably stable silenes 2 and 3 featuring zwitterionic distribution of electron density. Co‐oligomerization of 1 and its germanium analogue gives a related tetrameric product 4 containing low‐valent germanium atom stabilized by binding with the partial carbene‐character C atom. Bonding situations in 2 – 4 are best described as silene or germene with the significant zwitterionic distribution of electron density. The singlet diradical electronic state of 2 is 10 kcal mol −1 higher than the ground state configuration.