Chlorosilanes experimental conditions

In order to probe the effect of junction point functionality on chain conformation and morphology of miktoarm star block copolymer architectures, a series of PI PS (n = 2, 4, 16) was synthesized [166]. A single batch of both living PS and PI arms have been used, in order to ensure that all chemically identical arms (either A or B) have the same molecular weights. The living A and B chains were reacted with the appropriate chlorosilane, under appropriate experimental conditions, to produce the corresponding //-stars, as shown in Scheme 88. 

The experimental conditions were essentially those already reported for the synthesis of the corresponding AB block copolymers. The only differences were the difunctional initiator (9) and the use of a difunctional rather than monofunctional chlorosilane for reaction with the... 

This cyclotrisilane was prepared through the reaction of NajAs with tris(trimethylsilyl)chlorosilane at 0°C in hexane. The carefully chosen experimental conditions led to the isolation of colorless crystals which could be purified by vacuum sublimation and recrystallization in -hexane. 

The direct formation of carbanion adjacent to amide nitrogen and further electrophilic substitution is a well-documented process in the synthesis of N-silylmethylamides, -carbamates, and ureas (38,119—138). Usually, the introduction of a silyl moiety to the a-position of a nitrogen atom occurs via the interaction of a-nitrogen carbanion with chlorosilane (Scheme 24.22). The compounds and experimental conditions for their synthesis by this method are shown in Table 24.8. 

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