Synthese des Cyclotetrasiloxans [(Me)(C6H4CH2NMe2-2)-SiO]4 und dessen strukturanalytische Untersuchung

The cyclotetrasiloxane [(Me)(C6H4CH2NMe2-2)SiO]4 (2) can be synthesized by hydrolysis of the pentacoordinated silicon compounds (C6H4CH2NMe2-2)MeSiCl2 (1) or (C6H4CH2NMe2-2)MeSi(OR)2 (3a, R=CH2CHCH2; 3b, R=CH2CCH) in quantitative yield. The solid-state structure of 2 is reported. Compound 2 crystallizes in the triclinic space group P-1 with the following cell parameters: a=9.575(2), b=15.018(3), c=16.021(4) Å; α=94.72(12), β=90.96(2), γ=103.75(2)°; V=2228.5(9) Å3 and Z=2. Due to sterical hindrance the silicon atoms in 2 are tetra-coordinated, which differs from the starting materials 1, 3a and 3b, where hypervalent silicon centers exist.