Selective Synthesis and Derivatization of Alkali Metal Silanides MSi(SiH₃)₃

Abstract

Greetings from silicon valley: Alkali metal silanides (H(3)Si)(3)Si(-)M(+) were shown to be selectively accessible for the first time by the reaction of neopentasilane Si(SiH(3))(4) with tBuOM or iPr(2)NLi. The method allows the convenient derivatization of higher silicon hydrides and provides a simple access for unprecedented systematic studies on the chemical behavior of hydropolysilanes (see scheme).

Branched Hydrosilane Oligomers as Ideal Precursors for Liquid‐Based Silicon‐Film Deposition

“…When a solution of (H 3 Si) 3 SiLi in diethyl ether was added to SiCl 4 at −80 °C, 3 and 4 were again obtained as the major products along with significant quantities of neo ‐Si 5 Cl 12 ( 5 ). The formation of isolable amounts of 5 starting from SiCl 4 is remarkable, since the state‐of‐the art educts for the synthesis of neo ‐Si 5 Cl 12 are Si 2 Cl 6 or Si 3 Cl 8 ,. Previously reported related reactions strongly suggest that dichlorosilylene is a likely intermediate in the course of the formation of 5 in the present case.…”

“…A plausible mechanism responsible for the unexpected formation of 5 is given in Scheme . When 1,1,1‐trichloroneopentasilane ( 6 ), prepared independently from 1,1,1‐triphenylneopentasilane and anhydrous HCl/AlCl 3 , was treated with one equivalent of 2 , exactly the same products as described above were obtained. Thus, we assume that in the first step compound 6 is formed by salt metathesis from 2 and SiCl 4 .…”

“…When we treated 1 with an ether solution of the lithium silanide LiSi(SiH 3 ) 3 ( 2 ), we detected 3 in the resulting reaction solution by 29 Si NMR spectroscopy along with Si 2 H 6 and higher perhydrosilane oligomers of unidentified composition. (Scheme ).…”

Dodecamethoxyneopentasilane as a New Building Block for Defined Silicon Frameworks

“…The reaction of 5 a – c with iodomethane yielded the expected methylisotetrasilane 6 in excellent yields. The selective formation of 6 was not surprising for us, as also 1 and 2 reacts with iodomethane to the corresponding methylisotetrasilanes [5,10] . Interestingly, the reaction with iodobenzene also gave rise to the selective formation of 7 in isolated yields >70 % (Scheme 4).…”

“…Additionally, Stueger et al . succeeded in the synthesis of perhydrogenated oligosilyl anions 2 , [10] which were used for the preparation of highly branched oligosilicon hydrides. These compounds are found to be ideal precursors for the liquid‐phase deposition of silicon films [11]…”