Premium
Structures and Properties of Phenylene‐Bridged 1,3‐Diaza‐2‐silole and Related 2 H ‐Azasilirenes Obtained by the Reactions of a Dialkylsilylene with Arylnitriles
Author(s) -
Ishida Shintaro,
Uchida Kenya,
Mori Maiko,
Iwamoto Takeaki
Publication year - 2019
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201900590
Subject(s) - chemistry , silylene , cycloaddition , nitrile , carbene , phenylene , photochemistry , dimethyl acetylenedicarboxylate , medicinal chemistry , computational chemistry , silicon , organic chemistry , catalysis , polymer
Cycloadditions of silylenes (silicon analogues of carbene) have been extensively explored as convenient and efficient routes to silacycles. Among these, reactions of silylenes with nitriles are still limited and the electronic properties of the resulting azasilacycles such as 2 H ‐azasilirene and 1,3‐diaza‐2‐siloles are less examined. We report herein synthesis of a phenylene‐bridged 1,3‐diaza‐2‐silole and C ‐aryl 2 H ‐azasilirenes using cycloaddition reactions of a silylene as well as their structures and UV/Vis absorption spectra. Treatment of an isolable dialkylsilylene with o ‐phthalonitrile afforded a phenylene‐bridged 1,3‐diazasilole and an isomeric dearomatized product. Similar reactions with p ‐substituted benzonitriles gave new 2 H ‐azasilirenes. UV/Vis absorption spectra and theoretical calculations showed that high‐lying n(C=N) orbitals in 1,3‐diaza‐2‐siloles and 2 H ‐azasilirenes and low‐lying π*(1,3‐diaza‐2‐silole) orbitals are important for their electronic characters. Computational studies revealed that 1,3‐dipolar cycloaddition of silylene nitrile complexes (nitrile silaylides) with the second nitrile and an aromatic C=C bond of 2‐cyanopheyl group are key steps for the cycloaddition.