Synthesis and properties of (trifluoromethyl)trichlorosilane, a versatile precursor for CF3Si compounds

(Trifluoromethyl)trichlorosilane (I) has been prepared for the first time by the reaction of CF3SiH(NMe2)2 (III) with HCl in dibutyl ether and, as a solution in CH2Cl2, by nucleophilic trifluoromethylation of SiCl4 with CF3Br/P(NEt2)3. From this solution, I may be isolated by HCl cleavage of its insoluble bis(pyridine) adduct (II). The aminosilane III was obtained from the reaction of HSi(Cl)(NMe2)2 with CF3Br/P(NEt2)3. Selective substitution of I without attack on the CF3Si moiety was achieved in high yields with SbF3 (→ CF3SiF3), Ag(OCN) (→ CF3Si(NCO)3 (IV)), MeOH (→ CF3Si(OMe)3 (V)), HNMe2 (→ CF3Si(NMe2)3 (VI)), LiAlH4 (→ CF3SiH3), MeMgBr (→ CF3SiMe3) and LiPh(→ CF3SiPh3 (VII)). With 2,2′-bipyridyl a 1/1 complex (VIII) was formed. The novel compounds I to VIII have been characterized by their IR, NMR and mass spectra, and for I a vibrational analysis including a normal coordinate treatment has been performed.