Synthesis, structures and reactions of lithium complexes of [(o-RCHC6H4)PPh2=NSiMe3]-(R = H, SiMe3) ligands.
N-Trimethylsilyl o-methylphenyldiphenylphosphinimine, (o-MeC6H4)PPh2=NSiMe3 (1), was prepared by reaction of Ph2P(Br)=NSiMe3 with o-methylphenyllithium. Treatment of 1 with LiBun and then Me3SiCl afforded (o-Me3SiCH2C6H4)PPh2=NSiMe3 (2). Lithiations of both 1 and 2 with LiBu(n) in the presence of tmen gave crystalline lithium complexes [Li{CH(R)C6H4(PPh(2=NSiMe3)-.tmen](3, R = H; 4, R = SiMe3). From the mother liquor of 4, traces of the tmen-bridged complex [Li{CH(SiMe3)C6H4(PPh2=NSiMe3)-2}]2(mu-tmen) (5) were obtained. Reaction of 2 with LiBun in Et2O yielded complex [Li{CH(SiMe3)C6H4(PPh2=NSiMe3)-2}.OEt2] (6). Reaction of lithiated with Me2SiCl2 in a 2:1 molar ratio afforded dimethylsilyl-bridged compound Me2Si[CH2C6H4(PPh2=NSiMe3)-2]2 (7). Lithiation of 7 with two equivalents of LiBun in Et2O yielded [Li2{(CHC6H4(PPh2=NSiMe3)-2)2SiMe2}.0.5OEt2](8.0.5OEt2). Treatment of 4 with PhCN formed a lithium enamide complex [Li{N(SiMe3)C(Ph)CHC6H4(PPh2=NSiMe3)-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(PPh2=NSiMe3)-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.
Wang
Zhong-Xia
ZX
Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China. zxwang@ustc.edu.cn
Qi
Chun-Yan
CY
D004602:Elements; D007097:Imines / Q000737:chemistry; D008024:Ligands; D008094:Lithium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010721:Phosphinic Acids / Q000737:chemistry; D012825:Silicon / Q000737:chemistry*; D014297:Trimethylsilyl Compounds / Q000138:chemical synthesis* / Q000737:chemistry* / Q000378:metabolism; D014961:X-Ray Diffraction
D004602:Elements; D007097:Imines; D008024:Ligands; D010721:Phosphinic Acids; D014297:Trimethylsilyl Compounds; D008094:Lithium; D012825:Silicon