Tris(2-phenylpyridine)iridium, abbreviated
r(ppy)3is the
organoiridium complex with the formula Ir(C
6H
4-C
5H
4N)
3. The complex, a yellow-green solid, is a derivative of Ir
3+ bound to three monoanionic 2-pyridinylphenyl
ligand
In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's el ...
s. It is
electroluminescent
Electroluminescence (EL) is an 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 resulting from ...
, emitting green light. The complex is observed with the facial stereochemistry, which is chiral.
The complex is prepared by cyclometalation reactions of
2-phenylpyridine and
iridium trichloride
Iridium(III) chloride is the inorganic compound with the formula IrCl3. The anhydrous compound is relatively rare, but the related hydrate is much more commonly encountered. The anhydrous salt has two polymorphs, α and β, which are brown and r ...
, as represented by this idealized equation:
:IrCl
3 + 3C
6H
5-C
5H
4N → Ir(C
6H
4-C
5H
4N)
3 + 3 HCl
The complex and many analogues have been investigated for application in
photoredox catalysis
Photoredox catalysis is a branch of photochemistry that uses electron transfer, single-electron transfer. Photoredox catalysts are generally drawn from three classes of materials: transition-metal complexes, organic dyes, and semiconductors. While ...
. Its excited state has a reduction potential of −2.14 V, nearly 1 V more negative than the reduction potential of excited
u(bipy)3sup>2+.
[{{cite journal , doi=10.1021/acs.accounts.6b00268, title=Fine Design of Photoredox Systems for Catalytic Fluoromethylation of Carbon–Carbon Multiple Bonds, year=2016, last1= Koike, first1=Takashi, last2=Akita, first2=Munetaka, journal= Accounts of Chemical Research, volume=49, issue=9, pages=1937–1945, pmid=27564676, doi-access=free]
References
2-Pyridyl compounds
Photochemistry
Organoiridium compounds