Equilibrium Formation of Stable All-Silicon Versions of 1,3-Cyclobutanediyl

Cem B Yildiz; Kinga I Leszczyńska; Sandra González-Gallardo; Michael Zimmer; Akin Azizoglu; Till Biskup; Christopher W M Kay; Volker Huch; Henry S Rzepa; David Scheschkewitz

doi:10.1002/anie.202006283

Equilibrium Formation of Stable All-Silicon Versions of 1,3-Cyclobutanediyl

Angew Chem Int Ed Engl. 2020 Aug 24;59(35):15087-15092. doi: 10.1002/anie.202006283. Epub 2020 Jun 15.

Authors

Affiliations

¹ Department of Aromatic and Medicinal Plants, Aksaray University, 68100, Aksaray, Turkey.
² Krupp-Chair of Inorganic and General Chemistry, Saarland University, 66123, Saarbrücken, Germany.
³ Department of Chemistry, Faculty of Science and Letters, University of Balıkesir, 10145, Balıkesir, Turkey.
⁴ Chair of Physical Chemistry and Chemical Education, Saarland University, 66123, Saarbrücken, Germany.
⁵ London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London, WC1H 0AH, UK.
⁶ Department of Chemistry, Imperial College London, MSRH, White City Campus, 80 Wood Lane, London, W12 0BZ, UK.

Abstract

Main group analogues of cyclobutane-1,3-diyls are fascinating due to their unique reactivity and electronic properties. So far only heteronuclear examples have been isolated. Here we report the isolation and characterization of all-silicon 1,3-cyclobutanediyls as stable closed-shell singlet species from the reversible reactions of cyclotrisilene c-Si₃ Tip₄ (Tip=2,4,6-triisopropylphenyl) with the N-heterocyclic silylenes c-[(CR₂ CH₂ )(NtBu)₂ ]Si: (R=H or methyl) with saturated backbones. At elevated temperatures, tetrasilacyclobutenes are obtained from these equilibrium mixtures. The corresponding reaction with the unsaturated N-heterocyclic silylene c-(CH)₂ (NtBu)₂ Si: proceeds directly to the corresponding tetrasilacyclobutene without detection of the assumed 1,3-cyclobutanediyl intermediate.

Keywords: diradicaloids; low-valent species; silicon; small ring; synthesis.

Abstract

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