Abstract: | Alternative Ligands. XXI. Novel Donor/Acceptor Ligands Me2PCH2CH2SiFnMe3-n, Me2PCH2CH2SiR(C6H4F)2, and (2-Me2PC6H4)SiXMe2 Donor/acceptor ligands of the type Me2PCH2CH2SiX3 [X = Cl ( 1 ), F ( 2 ), Me ( 3 ), OMe ( 4 )], (Me2PCH2CH2)2SiX2 [X = Cl ( 6 ), F ( 7 )], Me2PCH2CH2SiX(C6H4F)2 [X = F ( 5 ), Me ( 8 )], and Me2PCH2CH2SiXnMe3-n[n = 1; X = Cl ( 10 ), F ( 11 ); n = 2; X = F ( 9 )] are prepared in yields between 42 and 95% by photochemical addition of Me2PH to the corresponding vinylsilane precursors. In case of the halogen containing representatives formation of solid polyadducts, due to Lewis acid/base interaction between P-donor and Si-acceptor function, reduces the yields. Ligands of the type (2-Me2PC6H4)SiXMe2 [X = NMe2 ( 12 ), Cl ( 13 ), F ( 14 )] are obtained by two different routes (Abb. 3), using 2-chlorobromobenzene as the starting material. New compounds have been characterized by analytical (C, H) and spectroscopic (NMR, MS) investigations. In order to elucidate the associative properties compounds 2 and 9 were used for the following experiments: - – Study of the influence of dissolution on the proton and fluorine resonances of 2 and 9 ,
- – investigation of the adduct equilibrium (–H2CF3Si←PMe2CH2–)n + nBF3 → n[F3B←PMe2CH2CH2SiF3],
- – cleavage of the polyadduct of 2 using [NH4]F and [Me4N]F, respectively, for the formation of hexacoordinate complex anions [Me2PCH2CH2SiF5]2?.
The results obtained confirm the assumption that oligo- and polymerisation are due to P→Si interaction. |