Supersilyl substituents

Supersilyl substituents also stabilize negative charges extremely well In the radical anion of 1,4-di(tris(trimethylsilyl)silyl)benzene - as proven by ESR/ENDOR coupling constants [5a,c] augmented by HMO estimates for the "blind" centers (2 O) [5a,c] - more than half of the it spin population p is located in its Si(SiR3)3 groups. 

Summarizing, both the steric and electronic effects of supersilyl substituents, which stabilize radical cations as donors (1) and radical anions as acceptors (2), are recommended for further investigation. 

The chemistry of supersilyl substituents has been reviewed Wiberg, N. Coord. Chem. Rev. 1997, 163, 217. 

Supersilyl substituents are also well-suited to stabilize negative charges leading to Gui-nesss Book of Records results ... 

Therefore, NaBr elimination must produce a disilene with /rara-configured supersilyl groups, which cannot have any tendency for dimerization because of its overloaded supersilyl substituents. Its... 

Sterically Overloaded Silanes, Silylenes and Disilenes with Supersilyl Substituents tBuaSi... 

The highly strained tetrasilatetrahedrane structure can only be stabilized using extremely bulky substituents like the tri-i-butylsilyl (= supersilyl) group. Thus the only tetrasilatetrahedrane derivative known so far has been synthesized by coupling (t-Bu)3SiSiBr2SiBr2Si(Bu-t)3 with two equivalents of (i-Bu SiNa92 (equation 24). 

The synthetic potential of silicon substituents in organic and organometallic chemistry has by far not been fully exploited, which is evidenced by the numerous contributions in this chapter. This is examplified for the description of the silyl group as a substituent and as a functional group in carbene and carbenoid chemistry, for the function of the trimethylsilyl substituent in the synthesis of low-valent compounds containing elements ofgroup 15 andfor the influence of a supersilyl ligand to a phosphorous center. 

In this connection, we asked ourselves if disilyne with overloaded substituents has a linear structure analogous to acetylenes and if such an unsaturated system could be chemically demonstrated as a reaction intermediate or could even be isolated in substance. As overcrowded substituents we chose supersilyl groups, and as the method of preparation thermal salt elimination. 

Tetrasilatetrahedrane is accessible if the appropriate substituent is selected. As found in the case of the octasilacubane (/frr-BuMe2SiSi)s (15), silyl substituents decrease the strain in the polyhedrane (14). Thus, the synthesis of tetrasilatetrahedrane has been accomplished by use of the supersilyl group (/ert-BusSi) (10). 

The supersilyl- Si(CMe3)3 and the hypersilylgroup Si(SiMe3)3 are exceptionally well suited to stabilize unusual structures that are otherwise prone to chemical attack. Here we report on the synthesis of some new cyclic and cage-like structures from elements of group 15 stabilized by the hypersilyl substituent. 

As substituent R in 1 we used the tri-tert-butylsilyl group SitBua, which we call supersilyl and symbolize as R. And indeed, this moiety is an overcrowded one three bulky tertiary butyl groups fully shield a silicon atom on one side and leave only a small place for a fourth substituent on the... 

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