Synthesis of cyclotetrasiloxane [(Me)(C6H4CH2NMe2-2)-SiO](4) and its structural analysis

The cyclotetrasiloxane [(Me)(C6H4CH2NMe2-2)SiO](4) (2) can be synthesized b y hydrolysis of the pentacoordinated silicon compounds (C6H4CH2NMe2-2)MeSiC l2 (1) or (C6H4CH2NMe2-2)MeSi(OR)(2) (3a, R=CH2CH=CH2; 3b, R=CH2C=CH) in qu antitative yield. The solid-state structure of 2 is reported. Compound 2 cr ystallizes in the triclinic space group P-1 with the following cell paramet ers: a = 9.575(2), b = 15.018(3), c = 16.021(4) Angstrom; alpha = 94.72(12) , beta = 90.96(2), gamma = 103.75(2)degrees; V = 2228.5(9) Angstrom (3) and Z = 2. Due to sterical hindrance the silicon atoms in 2 are tetra-coordina ted, which differs from the starting materials 1, 3a and 3b, where hyperval ent silicon centers exist. (C) 2001 Elsevier Science B.V. All rights reserv ed.