Hexakis cyclotrisilane

Hexakis(2,6-dimethylphenyl)cyclotrisilane, the first known stable three-membered cyclosilane, was prepared in 1982 by Masamune and coworkers from dichlorobis(2,6-dimethylphenyl)silane by the reductive dechlorination with lithium naphthalenide in low yield34. Other cyclotrisilanes bearing substituents of comparable steric bulk have been synthesized analogously. The chemistry of the cyclotrisilanes presently known has recently been reviewed35. 

The aminofunctional cyclotrisilane derivative hexakis[2-(dimethylaminomethyl)phenyl] cyclotrisilane can be formed by the reductive dechlorination of the corresponding dichloride Ar2SiCl2 (Ar = 2-Me2NCH2C6H4) with magnesium41. 

Addition of phenylacetylene or pent-l-yne to a solution of hexakis[2-(dimethylamino-methyl)phenyl]cyclotrisilane yields spectroscopically pure 1,2-disilacyclobutenes (equation 9)41. 

The NMR resonances for the central 29Si nuclei of tetrakis(trialkylsilyl)disilene complexes in solution vary from —160 ppm for 241 to 127 ppm for 240, depending on the bonding characteristics of the disilene ligands to the metals for reference, the 29Si NMR resonances for hexakis(trialkylsilyl)cyclotrisilanes and free disilene 22 are... 

In addition, cyclotrisilane derivatives can be subjected to photolysis to generate organylsilylenes. For instance, the photolysis of hexakis-t-butylcyclotrisilane (369) in the presence of substituted acetylenes, e.g. (370) affords 1,1,4,4-tetrakis-t-butyl-2,3,5,6-tetraorganyl-l,4-disilacyclohexa-2,5-diene (371) (equation 167)190. Alternatively, thermolysis of disilanes in the presence of alkynes is a viable route to disilacyclohexane derivatives. Thus, thermolysis of l,2-dimethoxy-l,l,2,2-tetramethyldisilane (338) in the presence of diphenylacetylene (370) in a pressure vessel—via reactive intermediates and,... 

Through the reaction of (Na/K)3M (M = P, As, Sb, Bi) with XSi[Si(CH3)3]3 (X= 1, Br, Cl, F, PhS, CF3SO3) we prepared various cyclic M-Si compounds such as the P7 cage. Using suitable conditions these reactions tend to yield unexpected cyclic and cage-like structures through rearrangement, for instance hexakis(trimethylsilyl)cyclotrisilane. 

Fig. 4. Structure of hexakis(trimethylsilyl)cyclotrisilane [Si(SiMe3)2]3-Hypersilylphosphine H2PSi(SiMe3)...

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