Trilithium Heptaphosphide

The reaction of trilithium heptaphosphide with bromomethane in THF at — 60 °C leads to trimethylheptaphosphane, P7(CH3)3. Yield 93%. The condensation of Li3 7 with the diphosphane Cl(t-C4H9)P—P(t-C4H9)C1 yields the tetracyclic nonaphosphide LiP9(t-C4H9)2, which has a skeleton analogous to that of the hydrocarbon deltacyclane.  

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TRILITHIUM HEPTAPHOSPHIDE, DILITHIUM HEXADECAPHOSPHIDE, AND TRISODIUM HENICOSAPHOSPHIDE... 

Trilithium heptaphosphide, dilithium hexadecaphosphide, and trisodium henicosaphosphide are polyphosphides with isolated anions in the solid state as well as in solution. These metalated poly phosphorus compounds are of interest because of their structural relationship to the phosphorus hydrides (phosphanes) and organophosphanes P.R and particularly because of their potential use as building blocks for the syntheses of polyphosphorus compounds. 

The structural peculiarity of trilithium heptaphosphide is its fluctuating anion.On account of the structural similarity to the hydrocarbon bullvalene, the P7 ion is capable of a degenerate Cope rearrangement and at room temperature has to be described by 1680 valence-tautomeric forms of equal structure. 

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