Lithium phosphide complexes

Figures 12.2.7(e)-(g) show the core structures of three lithium phosphide complexes. Li(l t20)2(P Bu)2(Ga 2Bu3) has a puckered Ga2P2 four-membered ring, in which one Ga atom is four- and the other three-coordinated, as shown in Fig. 12.2.7(e). The Li-P bond length is 266 pm(av.).

In 1989 we reported on the synthesis and structure of the first l,3-diphospha-2-sila-allylic anion 3a [4], mentioning its value as a precursor for phosphino-silaphosphenes. In analogy to 3a we obtained the anions 3b-f [5] by treatment of 4 equivalents of the lithium phosphide 1 with the adequately substituted RSiC, of which 3b and 3c were investigated by X-ray analyses. The very short P-Si bond lengths (2.11-2.13 A) of 3a-c and the almost planar arrangement of Pl-Sil-P2-Lil indicate the cr-character of the Lithium P-Si-P allyl complex. 

Wright et al. have reported two cases where LiPHCy acts as a precursor to main group phosphinidine complexes. Reaction of the primary lithium phosphide with [AlMe N(mes) ]4 gives the heterometallic cage complex Li(THF) 4[ (AlMe)(ja-PCy) 2(ju.-PCy)]2 C6H5Me (95) (Fig. 12a). Reaction of [SnNBut]4 with 6 equiv of LiPHCy yields the complex cluster [ Sn2(PCy)3 2 Li(THF) 4], 2THF (96) (Fig. 12b). 

Heterometallic alkali metal phosphide complexes with transition metals have also been reported. The complex [(Cy2P)3Hf(ju.-PCy2)2Li (DME)] results from the reaction of LiPCy2 with HfCl4(THF) (98). This complex persists in solution. Jones et al. have reported the synthesis and reactivity toward a range of electrophiles of a series of lithium di-t-butylphosphido(alkyl)cuprates [RCu(PBu2)Li] (R = Me,... 

Ethylphosphorus reacts with various amounts of phenyl-lithium to give the lithium phosphides (8), which are more reactive than ethylphosphorus towards phenyl-lithium and can react further to give complex mixtures of other lithium phosphides. Unsaturated phosphines (9) have been prepared with high stereospecificity by the addition of di-t-butylphosphine to... 

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