N-Trimethylsilyl o-methylphenyldiphenylphosphinimine, (o-MeC6H4)PPh2NSiMe3
(1), was prepared by reaction of Ph2P(Br)NSiMe3 with o-methylphenyllithium. Treatment of 1 with LiBun and then Me3SiCl afforded (o-Me3SiCH2C6H4)PPh2NSiMe3
(2). Lithiations of both 1 and 2 with LiBun in the presence of tmen gave crystalline lithium complexes [Li{CH(R)C6H4(PPh2NSiMe3)-2}·tmen]
(3, R = H; 4, R = SiMe3). From the mother liquor of 4, traces of the tmen-bridged complex [Li{CH(SiMe3)C6H4(PPh2NSiMe3)-2}]2(µ-tmen)
(5) were obtained. Reaction of 2 with LiBun in Et2O yielded complex [Li{CH(SiMe3)C6H4(PPh2NSiMe3)-2}·OEt2]
(6). Reaction of lithiated 1 with Me2SiCl2 in a 2:1 molar ratio afforded dimethylsilyl-bridged compound Me2Si[CH2C6H4(PPh2NSiMe3)-2]2
(7). Lithiation of 7 with two equivalents of LiBun in Et2O yielded [Li2{(CHC6H4(PPh2NSiMe3)-2)2SiMe2}·0.5OEt2]
(8·0.5OEt2). Treatment of 4 with PhCN formed a lithium enamide complex [Li{N(SiMe3)C(Ph)CHC6H4(PPh2NSiMe3)-2}·tmen]
(9). Reaction of two equivalents of 5 with 1,4-dicyanobenzene gave a dilithium complex [{Li(OEt2)2}2(1,4-{C(N(SiMe3)CHC6H4(PPh2NSiMe3)-2}2C6H4)]
(10). All compounds were characterised by NMR spectroscopy and elemental analyses. The structures of compounds 2, 3, 5, 6 and 9 have been determined by single crystal X-ray diffraction techniques.
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