Isolation of Silacycles from the Reactions of a Monochlorosilylene LSi(:)Cl (L = PhC(N t Bu)2) with Ethynyl Lithium Salts

Chenghuan Liu; Rui Liu; Chenfeng Wang; Yanyan Tang; Zheng-Feng Zhang; Ming-Der Su; Yan Li

doi:10.1021/acs.inorgchem.2c01762

Isolation of Silacycles from the Reactions of a Monochlorosilylene LSi(:)Cl (L = PhC(N t Bu)₂) with Ethynyl Lithium Salts

Inorg Chem. 2022 Oct 10;61(40):15864-15870. doi: 10.1021/acs.inorgchem.2c01762. Epub 2022 Sep 30.

Authors

Chenghuan Liu^{1

2}, Rui Liu^{1

2}, Chenfeng Wang^{1

2}, Yanyan Tang^{1

2}, Zheng-Feng Zhang³, Ming-Der Su^{3

4}, Yan Li^{1

2}

Affiliations

¹ College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, Hangzhou 311121, China.
² Key Laboratory of Silicone Materials Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou 311121, China.
³ Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan.
⁴ Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.

PMID: 36178201
DOI: 10.1021/acs.inorgchem.2c01762

Abstract

The reactions of amidinate silylene chloride LSi(:)Cl (L = PhC(NtBu)₂) with TMS- and Ph-ethynyl lithium salts gave rise to silacycles 1 and 4, respectively. The formation of 1 and 4 may undergo cyclo-condensations of transient ethynylsilylene intermidiates and the activation of an amidinate backbone. The distinct structures of 1 and 4 may be derived from the different electronic or steric properties of ethynyl substituents, and their formation mechanisms were investigated by density functional theory (DFT) calculations. Moreover, a sequential reaction of LSi(:)Cl with BH₃·SMe₂ and TMSC≡CLi as well as a reaction of LSi(:)Cl with TMSC≡CLi under O₂ exclusively obtained ethynylsilanes 2 and 3, respectively, which indicated that either blocking a lone pair of a Si(II) atom or oxidizing Si(II) to Si(IV) prevents the further conversion of ethynylsilylenes to silacycle 1. All products were characterized by NMR spectroscopy and X-ray crystallography.