title: A Two-Coordinate Cyclic (Alkyl)(amino)silylene: Balancing Thermal Stability and Reactivity.
abstract: A crystalline two-coordinate cyclic (alkyl)(amino)silylene (1) was successfully synthesized and isolated. Its29Si NMR and UV/Vis spectra indicate that the electronic properties of 1 fall between those of cyclic dialkylsilylenes and diaminosilylenes. At very low temperature, the color of a solution of 1 turned from colorless to yellow, which was monitored by UV/Vis spectroscopy. DFT calculations supported the hypothesis that head-to-head dimers (disilenes) with a very long Si-Si distance are formed at such low temperatures. Although 1 is thermally stable, it readily undergoes cycloadditions, Si-H insertions, and photochemical reactions with benzene similar to dialkylsilylenes. At higher temperatures, 1 is also susceptible to intermolecular benzylic C-H insertion reactions, as well as unprecedented dehydrogenation reactions with cyclohexa-1,4-diene and 9,10-dihydroanthracene to afford benzene and anthracene, respectively.
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai, 980-8578, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kosai
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai, 980-8578, Japan.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Ishida
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai, 980-8578, Japan.
authors.forename: Takeaki
authors.initials: T
authors.lastname: Iwamoto
keywords: X-ray diffraction; carbenes; photochemistry; silicon; structure elucidation