摘要:
KR*Si-3(4), 2, (R* = SitBu(3)), formed by the reaction of R*Si-4(4) with 2 KC8, is an orange red solid stable at r.t. but decomposes in solution into R*Si-4(4) and a compound that reacts with excess Me3SiCl to form (Me3Si)(4)R*3ClSi8. Compound 2 is very sensitive to air and moisture. Its alcoholysis does not stabilize the protonated species HR*Si-3(4) and ends up in R*3Si3H3. Compound 2 reacts with 1/2 equivalent ICl to form a violet solid R*Si-6(8). A 1:1 reaction of 2 with SiBr4 runs differently to form ditetrahedranyl, R*Si-3(4)-Si4R*(3) which is stable at r.t. but transforms into its violet isomer R*Si-6(8) at higher temperatures. Compound 2 crystallizes as R*3Si4K(18-crown-6) and its crystal structure shows a Si-4-cage with a short Si-K linkage. It opens up at higher temperatures to acquire a unique structure in which a -CH2-CH2-group detaches itself from an ether to insert into Si-Si linkage of Si-4-unit to form a bicyclic ring. The residual chain (CH2)(10)O-6 closes itself on to a Si atom to form R*Si-3(3)(CH2-CH2)Si(C10H20O6)K(18-C-6). (C) 2009 Elsevier B.V. All rights reserved.