ALTERNATIVE LIGANDS .21. 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 Me2PCH2CH2SiX(n)Me3-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: investigation of the adduct equilibrium (-H2CF2Si-PMe2CH2-)n + nBF3 greater than n[F3B2-PMe2CH2CH2SiF2], cleavage of the polyadduct of 2 using [NH4]F and [Me4N]F, respectively, for the formation of hexacoordinate complex anions [Me3PCH2CH2SiF5]3-. The results obtained confirm the assumption that oligo- and polymerization are due to P-Si interaction.