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In chemistry
Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...
, phosphine-boranes are 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 R3−nHnPBH3. They are Lewis acid-Lewis base adducts derived from organophosphine
Organophosphines are organophosphorus compounds with the formula PR''n''H3−''n'', where R is an organic substituent. These compounds can be classified according to the value of ''n'': primary phosphines (''n'' = 1), secondary phosphin ...
s (PR3−nHn) and borane
Borane is an inorganic compound with the chemical formula . Because it tends to dimerize or form adducts, borane is very rarely observed. It normally dimerizes to diborane in the absence of other chemicals. It can be observed directly as a c ...
(BH3). They are generally colorless or white solids. Since these adducts are air-stable, they represent a protected
Protection is any measure taken to guard something against damage caused by outside forces. Protection can be provided to physical objects, including organisms, to systems, and to intangible things like civil and political rights. Although ...
form of the parent organophosphine.
Formation and decomplexation
Typically phosphine-boranes are produced by treating the parent phosphine with a source of borane: :PR3−nHn + BH3 → R3−nHnPBH3 Because borane solutions are expensive or dangerous, the borane is often generated in situ, e.g., by oxidation of borohydride with iodine.{{cite book , doi=10.1002/9780470132463.ch29, chapter=Methyldiphenylphosphine-Borane and Dimethylphenylphosphine-Borane, series =Inorganic Syntheses, year=2007, last1=Mathur, first1=M. A., last2=Myers, first2=W. H., last3=Sisler, first3=H. H., last4=Ryschkewitsch, first4=G. E., title=Inorganic Syntheses , pages=128–133, volume=15, isbn=9780470132463 Deprotection to liberate the phosphine is often achieved by treatment with atertiary amine
In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of elec ...
:
:R3−nHnPBH3 + R'3N → R'3NBH3 + R3−nHnP
See also
*Frustrated Lewis pair
A frustrated Lewis pair (FLP) is a compound or mixture containing a Lewis acid and a Lewis base that, because of steric hindrance, cannot combine to form a classical adduct. Many kinds of FLPs have been devised, and many simple substrates exhibit ...
, where the borane is often tris(pentafluorophenyl)borane
* Ammonia borane
Ammonia borane (also systematically named ammoniotrihydroborate), also called borazane, is the chemical compound with the formula . The colourless or white solid is the simplest molecular boron-nitrogen-hydride compound. It has attracted attention ...
, related to phosphine-borane but with ammonia or amines in place of organophosphines
References