Triphenylamine is an
organic compound
Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...
with
formula
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...
(C
6H
5)
3N. In contrast to most
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 ...
s, triphenylamine is nonbasic. At room temperature it appears as a colorless crystalline solid, with monoclinic structure. It is well miscible in
diethyl ether
Diethyl ether, or simply ether, is an organic compound with the chemical formula , sometimes abbreviated as . It is a colourless, highly Volatility (chemistry), volatile, sweet-smelling ("ethereal odour"), extremely flammable liquid. It belongs ...
and
benzene
Benzene is an Organic compound, organic chemical compound with the Chemical formula#Molecular formula, molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal Ring (chemistry), ring with one hyd ...
, but it is practically insoluble in
water
Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...
, and partially in
ethanol
Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...
. Its derivatives have useful properties in electrical conductivity and
electroluminescence
Electroluminescence (EL) is an optical phenomenon, optical and electrical phenomenon, in which a material emits light in response to the passage of an electric current or to a strong electric field. This is distinct from black body light emission ...
, and they are used in
OLED
An organic light-emitting diode (OLED), also known as organic electroluminescent (organic EL) diode, is a type of light-emitting diode (LED) in which the emissive electroluminescent layer is an organic compound film that emits light in respon ...
s as hole-transporters.
Triphenylamine can be prepared by
Ullmann arylation of
diphenylamine
Diphenylamine is an organic compound with the formula (C6H5)2NH. The compound is a derivative of aniline, consisting of an amine bound to two phenyl groups. The compound is a colorless solid, but commercial samples are often yellow due to oxidiz ...
.
Chemical properties
Triphenylamine has three aromatic groups directly linked to the central nitrogen atom. Each aromatic group acts as an electron attractor, directing the electron cloud of the
lone pair
In chemistry, a lone pair refers to a pair of valence electrons that are not shared with another atom in a covalent bondIUPAC ''Gold Book'' definition''lone (electron) pair''/ref> and is sometimes called an unshared pair or non-bonding pair. Lone ...
of nitrogen towards it. With the delocalization of the nitrogen lone pair, a partial positive charge is conferred to nitrogen, counterbalanced by the partial negative charge localized on the aromatic groups. This arrangement prevents nitrogen
protonation
In chemistry, protonation (or hydronation) is the adding of a proton (or hydron, or hydrogen cation), usually denoted by H+, to an atom, molecule, or ion, forming a conjugate acid. (The complementary process, when a proton is removed from a Brø ...
, a key mechanism for providing basicity to a solution.
From this characteristic, moreover, it follows that the three N-C bonds all lie on the same plane and that they are located at 120° from each other, which is not the case with
aliphatic 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 ...
s and
ammonia
Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...
, where the orbitals of nitrogen are arranged in a tetrahedron. Due to steric hindrance, the phenyl groups are not on the same plane defined by the three N-C bonds, but are twisted, giving the molecule its characteristic "propeller-like" shape.
[{{cite journal , doi=10.1107/S0108270185006217 , title=Structural investigation of the triaryl derivatives of the Group V elements. IX. Structure of triphenylamine, C18H15N , date=1985 , last1=Sobolev , first1=A. N. , last2=Belsky , first2=V. K. , last3=Romm , first3=I. P. , last4=Chernikova , first4=N. Yu. , last5=Guryanova , first5=E. N. , journal=Acta Crystallographica Section C Crystal Structure Communications , volume=41 , issue=6 , pages=967–971 , bibcode=1985AcCrC..41..967S ]
See also
*
Triarylamine
*
Triphenylphosphine
References
External links
International Chemical Safety Card 1366SDS sheet at www.sigmaaldrich.comSpectroscopy of triphenylamine (gas phase neutral, radical cation, protonated)
Tertiary amines
Phenyl compounds