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Borabenzene is a hypothetical
The borabenzene-pyridine adduct behaves like a 
organoboron compound
Organoboron chemistry or organoborane chemistry studies organoboron compounds, also called organoboranes. These chemical compounds combine boron and carbon; typically, they are organic derivatives of borane (BH3), as in the trialkyl boranes.
Or ...
with the formula C5H5B. Unlike the related but highly stable benzene molecule, borabenzene would be electron-deficient. Related derivatives are the boratabenzene anions, including the parent 5H5BHsup>−.
Adducts
Adducts of borabenzene withLewis base
A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any sp ...
s are isolatable. Since borabenzene is unavailable, these adducts require indirect methods. 4-Silyl-1-methoxyboracyclohexadiene is used as a precursor to the borabenzene:
: + → + MeOSiMe3
The pyridine adduct is structurally related to biphenyl
Biphenyl (also known as diphenyl, phenylbenzene, 1,1′-biphenyl, lemonene or BP) is an organic compound that forms colorless crystals. Particularly in older literature, compounds containing the functional group consisting of biphenyl less one ...
. It is a yellow whereas biphenyl is colorless, indicating distinct electronic structures. The pyridine ligand is tightly bound: no exchange is observed with free pyridine, even at elevated temperatures.
:
The borabenzene-pyridine adduct behaves like a diene
In organic chemistry, a diene ( ); also diolefin, ) or alkadiene) is a covalent compound that contains two double bonds, usually among carbon atoms. They thus contain two alk''ene'' units, with the standard prefix ''di'' of systematic nome ...
, not an analog
Analog or analogue may refer to:
Computing and electronics
* Analog signal, in which information is encoded in a continuous variable
** Analog device, an apparatus that operates on analog signals
*** Analog electronics, circuits which use analog ...
of biphenyl
Biphenyl (also known as diphenyl, phenylbenzene, 1,1′-biphenyl, lemonene or BP) is an organic compound that forms colorless crystals. Particularly in older literature, compounds containing the functional group consisting of biphenyl less one ...
, and will undergo Diels-Alder reactions.
:
See also
* 6-membered aromatic rings with one carbon replaced by another group: silabenzene, germabenzene, stannabenzene,pyridine
Pyridine is a basic (chemistry), basic heterocyclic compound, heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom . It is a highly flammable, weak ...
, phosphorine
Phosphorine (IUPAC name: phosphinine) is a heavier Chemical element, element analog of pyridine, containing a phosphorus atom instead of an aza- moiety. It is also called phosphabenzene and belongs to the phosphaalkene class. It is a colorless li ...
, arsabenzene, stibabenzene, bismabenzene, pyrylium
Pyrylium is a cation (positive ion) with formula , consisting of a six-membered ring of five carbon atoms, each with one hydrogen atom, and one positively charged oxygen atom. The bonds in the ring are conjugated as in benzene, giving it an aroma ...
, thiopyrylium
Thiopyrylium is a cation with the chemical formula C5H5S+. It is analogous to the pyrylium cation with the oxygen atom replaced by a sulfur atom.
Thiopyrylium salts are less reactive than the analogous pyrylium salts due to the higher polarizabi ...
, selenopyrylium
Selenopyrylium is an aromatic compound, aromatic heterocyclic compound consisting of a six-membered ring with five carbon atoms and a positively charged selenium atom.
Naming and numbering
Formerly it was named selenapyrylium. However, this is mi ...
, telluropyrylium
Telluropyrylium is an aromatic heterocyclic compound consisting of a six member ring with five carbon atoms, and a positively charged tellurium atom. Derivatives of telluropyrylium are important in research of infrared dyes.
Naming and numbering ...
* Borazine
Borazine, also known as borazole, inorganic benzene, is an inorganic compound with the chemical formula B3H6N3. In this cyclic compound, the three BH units and three NH units alternate. The compound is isoelectronic and isostructural with benz ...
References