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 (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 electr ...
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 h ...
, emitting green light. The complex is observed with the facial stereochemistry, which is chiral.
The complex is prepared by cyclometalation reactions of
2-phenylpyridine
2-Phenylpyridine is an organic compound with the formula C6H5C5H4N (or C11H9N). It is a colourless viscous liquid. The compound and related derivatives have attracted interest as precursors to highly fluorescent metal complexes of possible value ...
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 useful for preparing other iridium compounds. The anhydrous salt is a dark green crystalline solid. ...
, 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 single-electron transfer. Photoredox catalysts are generally drawn from three classes of materials: transition-metal complexes, organic dyes, and semiconductors. While organic photoredox ...
. 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