Institut für Anorganische und Analytische Chemie, J. W. Goethe-Universität Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt (Main), Germany.
School of Chemistry and Forensic Science, University of Kent, Park Wood Rd, Canterbury, CT2 7NH, UK.
Chemistry. 2023 Jan 18;29(4):e202203119. doi: 10.1002/chem.202203119. Epub 2022 Nov 28.
The B-nucleophilic 9H-9-borafluorene dianion reacts with 9-chloro-9-silafluorene to afford air- and moisture-stable silylborate salts M[Ar (H)B-Si(H)Ar ] (M[HBSiH], M=Li, Na). Li[HBSiH] and Me SiCl give the B-pyridine adduct Ar (py)B-Si(H)Ar ((py)BSiH) or the chlorosilane Li[Ar (H)B-Si(Cl)Ar ] (Li[HBSiCl]) in C H -pyridine or THF. In both cases, the first step is H abstraction at the B center. The resulting free borane subsequently binds a py or thf ligand. While the py adduct is stable at room temperature, the thf adduct undergoes a 1,2-H shift via the cyclic B(μ-H)Si intermediate BHSi, which is afterwards attacked at the Si atom by a Cl ion to give Li[HBSiCl]. DFT calculations were employed to support the proposed reaction mechanism and to characterize the electronic structure of BHSi. Treatment of Li[HBSiCl] with the N-heterocyclic carbene IMe introduces the neutral donor at the Si atom and leads to Ar (H)B-Si(IMe)Ar (HBSi(IMe)), a donor-acceptor-stabilized silylene.
B-亲核的 9H-9-硼氟二阴离子与 9-氯-9-硅氟芴反应，生成在空气和湿气中稳定的硅硼酸盐 M[Ar(H)B-Si(H)Ar]（M[HBSiH]，M=Li，Na）。Li[HBSiH]和 MeSiCl 生成 B-吡啶加合物 Ar(py)B-Si(H)Ar((py)BSiH)或氯硅烷 LiAr(H)B-Si(Cl)Ar在 C H-pyridine 或 THF 中。在这两种情况下，第一步是在 B 中心发生 H 提取。生成的游离硼烷随后结合一个 py 或 thf 配体。虽然 py 加合物在室温下稳定，但 thf 加合物通过环状 B(μ-H)Si 中间体 BHSi 发生 1,2-H 转移，随后由 Cl 离子攻击 Si 原子得到 Li[HBSiCl]。DFT 计算被用来支持所提出的反应机制，并对 BHSi 的电子结构进行了表征。Li[HBSiCl]与 N-杂环卡宾 IMe 处理引入 Si 原子上的中性供体，并得到 Ar(H)B-Si(IMe)Ar(HBSi(IMe))，这是一种供体-受体稳定的硅烯。
