Hexasilylbenzene, C₆(SiH₃)₆

Abstract

The title compound was obtained in a four-step synthesis start-central benzene ring intact. LiAIHl reduction of the resulting ing from (4-methoxypheny1)silane. Owing to the presence of hexakis[(trifluoromethylsulfonyloxy)silyl]benzene (5) finally activating p-methoxy groups in the key intermediate hexa-leads to crystalline, sublimable, air-stable C6(SiH3j6 (S), m.p. kis[(4-methoxyphenyl)silyl]benzene (4), the peripheral aryl 165°C. In the crystals (triclinic, space group Pi) the structure groups can be cleaved selectively from the silicon atoms with of the centrosymmetrical molecules approaches very closely trifluoromethanesulfonic acid, leaving the Si -C bonds to the point group D3dr as predicted from theoretical considerations.We report on the synthesis of hexasilylbenzene, C6(SiH3)6 (6). This molecule is of considerable interest regarding its structure and energy characteristics, but also as a precursor for cation and anion radicals, as an electron-rich ligand for organometallic compounds, as a multi-silicon-functional synthon, and as a single-component source of silicon and carbon for the deposition of silicon carbide. The compound is expected to suffer from very little, if any, sterical crowding as compared to the partially or fully methylated homologues Cb(SiMe& and C6(SiMe3)6, which were shown to have extremely puckered benzene ringsL',21. Though not prepared previously, the compound has been included in patents for chemical uapour deposition of surface coatings[31.Recent attempts to synthesize C6(SiH3)6 starting from phenyl-or (4-methylpheny1)silane were unsuccessful, since in the critical step (below) random cleavage by acid occurred with the key intermediates C6(SiH2Ph)6 and C6(SiH2C6H4-4-Me)6[41. Therefore, in a new effort, aryl groups with more strongly activating substitutents were chosen for the protecting aryl groups, which were expected to favour peripheral cleavage over "central" cleavage.Trichloro(4-methoxypheny1)silane (1) is prepared and converted into (4-methoxypheny1)silane (2)

Synthesis and functionalization of Poly[5,5′-(silylene)-2,2′-dithienylene]s using silyl triflate intermediates†

“…The ease of replacement of Y by OTf decreases in the order (Y substituent) of NEt 2 [41][42][43][44] Phenylsilanes, which are highly reactive towards the protodesilylation reaction, are ideal starting materials for the synthesis of novel silyl triflates. Eaborn and coworkers 45 studied the effects of the substituents Z on the rate of acid cleavage of p-Z-C 6 H 4 SiR 3 (Scheme 1) and found that the reaction rates fell significantly in the order (Z substituent) of OCH 3 …”

1,2-Di(silyl)benzene and 1,4-Dibromo-2,5-di(silyl)benzene

“…All attem pts to obtain l,2,4,5-tetra(silyl)benzene gave only the disilylated species with two of the four halogen atoms of the starting material remaining in the product. This result is surprising since the structural situation appears to be very similar for each substitution step in 1,2-dibromo-and in 1,2,4,5-tetrabromo-benzene, and also since even complete substitution was possible in hexachlorobenzene (to give hexa(silyl)benzene) [13], The structural data for 4 and 6 give no indication of any steric congestion, which could make steric ef fects responsible for the failure of the synthetic work. The orientation of the tolyl groups is also such that no covering of the reaction center is ex pected.…”

“…Depending on the substitution pattern of the monomers, different kinds of cross-linking are to be expected, which are leading to simple oligomers, rings, chains, or polydimensional networks [1]. Simple poly(silyl)-arenes bearing solely hydrogen at the silicon sub stituents were largely unknown until some very re cent studies, which have shown the way to at least a few of the possible poly(silyl)benzenes and their isomers [2], Following our own work on poly(silyl)alkanes [3][4][5][6][7], -alkenes [8][9][10], -alkynes [11,12], and -arenes [12], including hexa(silyl)benzene [13] and l,8-di(silyl)naphthalene [14], we now report the first synthesis of the title compounds, the silicon analogue of o-xylene and one of its brom inated derivatives.…”

Synthese, Funktionalisierung und Vernetzung Siliciumorganischer Polymere mit Hilfe von Silyltriflat-Intermediaten

“…Die Darstellung von Silyltriflaten durch Spaltung verschiedener Silicium-Element-Bindungen in Monosilanen mittels Trifluormethansulfonsäure wurde von Bassindale [43], Schmidbaur [44,45] und im eigenen Arbeitskreis [46 -50] …”