Cyclopentaphosphine is the

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

with the formula . It is prepared by the hydrolysis of cyclo-. Although only of theoretical interest, is parent of many related cyclic polyphosphines that are the subject of research.

Organic cyclophosphines

Organic cyclophosphanes are a family of

organophosphorus compound Organophosphorus chemistry is the scientific study of the synthesis and properties of organophosphorus compounds, which are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbo ...

s with the formula (RP)_n where R is an organic substituent. Many examples are known. They are white, air-sensitive solids which 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: :

Isomerism

The structures are complicated by the slow

pyramidal inversion In chemistry, pyramidal inversion (also umbrella inversion) is a fluxional process in compounds with a pyramidal molecule, such as ammonia (NH3) "turns inside out". It is a rapid oscillation of the atom and substituents, the molecule or ion pass ...

at phosphorus(III). In principle, many isomers are possible for ''cyclo''-, 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 , and is often represented by the symbol Ph (archaically φ) or Ø. The phenyl group is closely related to benzene and can be viewed as a benzene ...

substituents are equatorial in ''cyclo''-.{{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 Five-membered rings