Silicon–silicon π single bond

Soichiro Kyushin, Yoshikuni Kurosaki, Kyohei Otsuka, Haruna Imai, Shintaro Ishida, Toru Kyomen, Minoru Hanaya, Hideyuki Matsumoto

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


A carbon–carbon double bond consists of a σ bond and a π bond. Recently, the concept of a π single bond, where a π bond is not accompanied by a σ bond, has been proposed in diradicals containing carbon and heteroatom radical centers. Here we report a closed-shell compound having a silicon–silicon π single bond. 1,2,2,3,4,4-Hexa-tert-butylbicyclo[1.1.0]tetrasilane has a silicon−silicon π single bond between the bridgehead silicon atoms. The X-ray crystallographic analysis shows that the silicon−silicon π single bond (2.853(1) Å) is far longer than the longest silicon−silicon bond so far reported. In spite of this unusually long bond length, the electrons of the 3p orbitals are paired, which is confirmed by measurement of electron paramagnetic resonance, and magnetic susceptibility and natural bond orbital analysis. The properties of the silicon−silicon π single bond are studied by UV/Vis and 29Si NMR spectroscopy, and theoretical calculations.

Original languageEnglish
Article number4009
JournalNature Communications
Issue number1
Publication statusPublished - 2020 Dec 1


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