Phosphorus reaction with phosphide anions

In some cases, the phosphide anions produced in reactions also contain hydrogen atoms boimd to the structure. Thus, a recent example has shown that direct reduction of white phosphorus with sodium in liquid ammonia generates the catena-trihydrogen triphosphide... 

The generation of phosphine (and the phosphide anion) from elemental phosphorus for use in this type of reaction is common. While unreactive with neutral water (although undergoing rapid oxidation with oxygen at 34 °C), elemental phosphorus (white, P4) generates phosphine readily in basic medium. On heating above 400 °C, white phosphorus [P4] generates a different allotropic form known as red phosphorus in which a P-P bond within the fundamental P4 tetrahedron is broken and individual tetrahedra are linked in a polymeric chain. This form of elemental phosphorus is less reactive that white phosphorus, but still is quite useful for synthetic purposes. 

The reactivity of metal phosphide cations [MPJ+, and anions [MPJ , may also be studied in the gas phase. Laser ablation of mixtures of cobalt or nickel metal powders with red phosphorus gave a range of anions M PJ and cations [MPJ+ (185). The anions were unreactive, but the cations have been reacted with several neutral molecules. The ions [MPJ+, where M = Co, Ni and x = 2,4, 8, undergo five types of reactions. 

Because of the solubility of alkali metals in NH3 (1), some alkali metal phosphides have been prepared from NH3(1). Reactions in solvents, either by using compounds containing polyanions or, in the course of suitable syntheses, from compounds starting with isolated phosphorus anions or from... 

This was accomplished by coupling either an amine or a phosphide with a silyl halide, followed by metalation. In the case of the obtained aminosilane, the subsequent metalation proceeded smoothly resulting in a stable aminosilylanion. In the case of phosphorus, we observed the formation of the phosphinosilyl anion by NMR, but the compound was not stable under the reaction conditions and rearranged to give the potassium phosphide. 

Up to now, metal phosphides have mainly been obtained either by solid-state synthetic techniques, under extreme conditions with long reaction times, or via the molecular phase to enable their use in the preparation of new materials. However, the renaissance and subsequent development of the chemistry of catenated oligophosphanide anions and their metal complexes may open up novel routes for the preparation of metal phosphides by thermal treatment of phosphorus-rich metal complexes. 

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