Cyclopentaphosphine is the

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemi ...

with the formula (PH)₅. It is prepared by the hydrolysis of cyclo- SiMe₃sub>4 (Me = methyl). Although only of theoretical interest, (PH)₅ is parent of many related cyclic polyphosphines that are the subject of research.

Organic cyclophosphines

Organic cyclophosphanes are a family of

organophosphorus compound Organophosphorus compounds are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective in ...

s with the formula (RP)_n where R is an organic substituent. Many examples are known. They are white, air-sensitive solids with have good solubility in organic solvents. Well-characterized examples are known for ring sizes 3–6. The three-membered rings feature bulky substituents, e.g., 'tert''-BuPsub>3. The cyclophosphines can be prepared by several methods, one involves reductive coupling of dichlorophosphines: :5PhPCl₂ + 5 Mg → hPsub>5 + 5MgCl₂

Isomerism

The structures are complicated by the slow pyramidal inversion at phosphorus(III). In principle, many isomers are possible for ''cyclo''-P₅R₅, but usually only one is observed. All

phenyl In organic chemistry, the phenyl group, or phenyl ring, is a cyclic group of atoms with the formula C6 H5, and is often represented by the symbol Ph. Phenyl group is closely related to benzene and can be viewed as a benzene ring, minus a hydroge ...

substituents are equatorial in ''cyclo''-P₆(C₆H₅)₆.{{cite journal , doi=10.1080/10426509308034357, title=Transformations of Difluorophosphines: The Influence of Solvent on the Reaction Pathway and Ring Size in Cyclopolyphosphines , year=1993 , last1=Schmutzler , first1=Reinhard , last2=Heuer , first2=Lutz , last3=Schomburg , first3=Dietmar , journal=Phosphorus, Sulfur, and Silicon and the Related Elements , volume=83 , issue=1–4 , pages=149–156

References

Phosphines Cyclic compounds Five-membered rings