| Abstract: | Synthesis and Properties of Partially Silylated Tri- and Tetraphosphanes. Reaction of Lithiated Diphosphanes with Chlorophosphanes The reactions of Li(Me3Si)P? P(SiMe3)(CMe3) 1 , Li(Me3Si)P? P(CMe3)2 2 , and Li(Me3C)P? P(SiMe3)(CMe3) 3 with the chlorophosphanes P(SiMe3)(CMe3)Cl, P(CMe3)2Cl, or P(CMe3)Cl2 generate the triphosphanes (Me3C)(Me3Si)P]2P(SiMe3) 4 , (Me3C)(Me3Si)P? P(SiMe3)? P(CMe3)2 6 , (Me3C)2P]2P(SiMe3) 7 , and (Me3C)(Me3Si)P? P(SiMe3)? P(CMe3)Cl 8 . The triphosphane (Me3C)2P? P(SiMe3)? P(SiMe3)2 5 is not obtainable as easily. The access to 5 starts by reacting PCl3 with P(SiMe3)(CMe3)2, forming (Me3C)2 P? PCl2, which then with LiP(SiMe3)2 gives (Me3C)2 P? P(Cl)? P(SiMe3)2 11 . Treating 11 with LiCMe3 generates (Me3C)2P? P(H)? P(SiMe3)2 16 , which can be lithiated by LiBu to give (Me3C)2P? P(Li)? P(SiMe3)2 13 and after reacting with Me3SiCl, finally yields 5 . 8 is stable at ?70°C and undergoes cyclization to P3(SiMe3)(CMe3)2 in the course of warming to ambient temperature, while Me3SiCl is split off. 7 , reacting with MeOH, forms (Me3C)2P]2PH. (Me3C)2P? P(Li)? P(SiMe3)2 18 , which can be obtained by the reaction of 5 with LiBu, decomposes forming (Me3C)2P? P(Li)(SiMe3), P(SiMe3)3, and LiP(SiMe3)2, in contrast to either (Me3C)2P? P(Li)? P(SiMe3)(CMe3) 19 or (Me3C)2P]2PLi, which are stable in ether solutions. The Li phosphides 1 , 2 , and 3 with BrH2C? CH2Br form the n-tetraphosphanes (Me3C)(Me3Si)P? P(SiMe3)]2? P(SiMe3)(CMe3) 23 , (Me3C)2P? P(SiMe3)]2? P(CMe3)2 24 , and (Me3C)(Me3Si)P? P(CMe3)]2? P(SiMe3)(CMe3) 25 , respectively. Li(Me3Si)P? P(SiMe3)2, likewise, generates (Me3Si)2P? P(SiMe3)]2? P(SiMe3)2 26 . Just as the n-triphosphanes 4 , 5 , 6 , and 7 , the n-tetraphosphanes 23 , 24 , and 25 can be isolated as crystalline compounds. 23 , treated with LiBu, does nor form any stable n-tetraphosphides, whereas 24 yields (Me3C)2P? P(Li)? P(SiMe3)? P(CMe3)2, that is stable in ethers. With MeOH, 24 , forms crystals of (Me3C)2P? P(H)? P(SiMe3)? P(CMe3)2. |
