biostudies-literatureUnknown28(69)Eisner TAn easily isolable silacycloheptatriene (silepin) 1 b was synthesized from the reaction of a N-heterocyclic imino (IPrN) substituted tribromosilane IPrNSiBr<sub>3</sub> with the sterically congested bis(trimethylsilyl)triisopropylsilyl silanide KSi(TMS)<sub>2</sub> Si(<sup>i</sup> Pr)<sub>3</sub> (BTTPS). In solution, the Si(IV) silepin 1 b is in a thermodynamic equilibrium with the acyclic Si(II) silylene 1 a. The relative concentration of the Si(II) or Si(IV) isomers can be controlled by temperature variation and observed by variable temperature NMR and UV/Vis spectroscopy. DFT calculations show a small reaction barrier for the Si(II)⇌Si(IV) interconversion and a small energy gap between the Si(II) and Si(IV) species. The reactivity of 1 a/b is demonstrated on a variety of small molecules.Chemistry (Weinheim an der Bergstrasse, Germany)e202202330https://www.ebi.ac.uk/biostudies/studies/S-EPMC10092829biostudies-literatureRoom-Temperature-Observable Interconversion Between Si(IV) and Si(II) via Reversible Intramolecular Insertion Into an Aromatic C-C Bond.PMC10092829Inoue SHanusch FKostenko AEisner TfalseRoom-Temperature-Observable Interconversion Between Si(IV) and Si(II) via Reversible Intramolecular Insertion Into an Aromatic C-C Bond.An easily isolable silacycloheptatriene (silepin) 1 b was synthesized from the reaction of a N-heterocyclic imino (IPrN) substituted tribromosilane IPrNSiBr<sub>3</sub> with the sterically congested bis(trimethylsilyl)triisopropylsilyl silanide KSi(TMS)<sub>2</sub> Si(<sup>i</sup> Pr)<sub>3</sub> (BTTPS). In solution, the Si(IV) silepin 1 b is in a thermodynamic equilibrium with the acyclic Si(II) silylene 1 a. The relative concentration of the Si(II) or Si(IV) isomers can be controlled by temperature variation and observed by variable temperature NMR and UV/Vis spectroscopy. DFT calculations show a small reaction barrier for the Si(II)⇌Si(IV) interconversion and a small energy gap between the Si(II) and Si(IV) species. The reactivity of 1 a/b is demonstrated on a variety of small molecules.2022-01-01T00:00:00Z2022 Dec2025-04-18T21:19:57.643Z2025-04-07T09:12:00.418ZS-EPMC100928293609849110.1002/chem.202202330