Phosphanides are chemicals containing the H₂sup>− anion. This is also known as the phosphino anion or phosphido ligand. The IUPAC name can also be dihydridophosphate(1−). It can occur as a group phosphanyl -PH₂ in organic compounds or ligand called phosphanido, or dihydridophosphato(1−). A related substance has PH²⁻. Phosphinidene (PH) has phosphorus in a −1 oxidation state. As a ligand PH₂ can either bond to one atom or be in a μ₂-bridged ligand across two metal atoms. With transition metals and actinides, bridging is likely unless the metal atom is mostly enclosed in a ligand. In phosphanides, phosphorus is in the −3 oxidation state. When phosphanide is oxidised, the first step is phosphinite ( ₂POsup>−). Further oxidation yields phosphonite ( PO₂sup>2−)and

phosphite The general structure of a phosphite ester showing the lone pairs on the P In organic chemistry, a phosphite ester or organophosphite usually refers to an organophosphorous compound with the formula P(OR)3. They can be considered as esters of ...

( O₃sup>3−). The study of phosphine derivatives is unpopular, because they are unstable, poisonous and they smell bad.

Formation

Alkali metal phosphanides can be made from

phosphine Phosphine ( IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula , classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotti ...

and the metal dissolved in

liquid ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous ...

. Sodium phosphanide can also be made from phosphine and triphenylmethyl sodium. Lithium phospahnide can be made from phosphine and

butyl lithium Butyllithium may refer to one of 5 isomeric organolithium reagents of which 3 are commonly used in chemical synthesis: * ''n''-Butyllithium, abbreviated BuLi or nBuLi * ''sec''-Butyllithium, abbreviated ''sec''-BuLi or sBuLi, has 2 stereoisomers, ...

phenyl lithium Phenyllithium or lithobenzene is an organometallic agent with the empirical formula C6H5Li. It is most commonly used as a metalating agent in organic syntheses and a substitute for Grignard reagents for introducing phenyl groups in organic synthes ...

. Another way to produce -PH₂ complexes is by hydrolysis of a -P(SiMe₃)₂ compound with an alcohol, such as methanol. Yet another way is to remove a hydrogen atom from the phosphine in a phosphine complex by using a string base.

Properties

When calcium phosphanide is heated, it decomposes by releasing

and yielding the phosphanediide: CaPH. With further heating a binary

calcium phosphide Calcium phosphide (CP) is the inorganic compound with the formula Ca3P2. It is one of several phosphides of calcium, being described as the salt-like material composed of Ca2+ and P3−. Other, more exotic calcium phosphides have the formula CaP ...

is formed. Other compounds may also lose hydrogen as well as phosphine. Phosphanides can react with CCl₄ to substitute Cl for H giving a -PCl₂ compound. Similarly CBr₄ can produce -PBr₂. Also AgBF₄ can react to yield -PF₂. Sodium phosphanide can react with ethyl alcohol in a diethyl carbonate solution to yield sodium 2-

phosphaethynolate The phosphaethynolate anion, also referred to as PCO, is the phosphorus-containing analogue of the cyanate anion with the chemical formula or . The anion has a linear geometry and is commonly isolated as a salt. When used as a ligand, the phosphae ...

(NaOCP). Na(DME)₂OCP is also formed from NaPH₂ when reacted with CO in a

dimethoxyethane Dimethoxyethane, also known as glyme, monoglyme, dimethyl glycol, ethylene glycol dimethyl ether, dimethyl cellosolve, and DME, is a colorless, aprotic, and liquid ether that is used as a solvent, especially in batteries. Dimethoxyethane is misc ...

(DME) solution under pressure.

List

Derivatives

Some derivatives of phosphanides have also been studied where hydrogen is substituted by another group. They include bis(trimethylsilyl)phosphanide, bis (triisopropylsilyl) phosphanide, bis (trimethylsilyl) phosphanide, diphenyl phosphanide.

References

{{Reflist Phosphines Ligands