SILOXANES AND SILYLAMINES WITH FLUOROMETHYL-METHYLSILICON GROUPS - X-RAY STUDY OF [CH2F(CH3)SIO](4)

CH(2)FMe(2)SiBr (II) was prepared by the reaction of CH(2)FMe(2)SiH wi th Br-2. The solvolysis of II with H2O and NH3 gave (CH(2)FMe(2)Si)(2) O (III) and (CH(2)FMe(2)Si)(2)NH (IV) respectively. After lithiation w ith n-BuLi and thereafter reaction with II, compound IV afforded the t risilylamine (CH(2)FMe(2)Si)(3)N (V). Hydrolysis of CH(2)FMeSiBr(2) (I ) with H2O yielded a polysiloxane oil from which 10% of a crystalline material (VI) was isolated. This was shown by analyses, mass, NMR and IR spectra to be the cyclotetrasiloxane (CH(2)FMeSiO)(4). The NMR spec tra suggest random distribution of all possible stereoisomers. Single crystals of VI were examined by X-ray diffraction. An essentially plan ar Si4O4 ring was found, the SiOSi angles averaging 157.9(5)degrees. S ince the F atoms are extensively disordered, packing requirements at a mbient temperature rather than the intrinsic conformational content of the crystal may be exerting the crystallographic inversion symmetry i mposed on the ring.