Acetylacetonatobis(2-phenylpyridine)iridium
[CAS# 337526-85-9]

Identification

• Classification: Pharmaceutical intermediate >> OLED material intermediate
• Name: Acetylacetonatobis(2-phenylpyridine)iridium
• Synonyms: Bis(2-phenylpyridine) (acetylacetonate) iridium(III)
• Molecular Formula: C₂₇H₂₃IrN₂O₂
• Molecular Weight: 599.71
• CAS Registry Number: 337526-85-9
• EC Number: 803-559-6
• SMILES: C/C(=C/C(=O)C)/O.C1=CC=C([C-]=C1)C2=CC=CC=N2.C1=CC=C([C-]=C1)C2=CC=CC=N2.[Ir]

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H315-H319-H335
• Precautionary Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin irritation	Skin Irrit.	2	H315

Discovory and Applicatios

Acetylacetonatobis(2-phenylpyridine)iridium is an organometallic complex featuring iridium as the central metal atom coordinated to two 2-phenylpyridine ligands and one acetylacetonate ligand. The chemical formula can be expressed as Ir(acac)(ppy)₂, where acac stands for acetylacetonate (a bidentate β-diketonate ligand) and ppy represents 2-phenylpyridine, a cyclometalating ligand that binds through carbon and nitrogen atoms.

This complex belongs to the family of cyclometalated iridium(III) compounds that have attracted significant interest due to their photophysical and catalytic properties. The octahedral coordination environment around the iridium center typically comprises the acetylacetonate ligand chelating via two oxygen atoms, and two 2-phenylpyridine ligands each binding through a carbon atom of the phenyl ring and a nitrogen atom of the pyridine ring, resulting in robust metal–ligand bonds.

The synthesis of acetylacetonatobis(2-phenylpyridine)iridium generally involves the reaction of an iridium precursor, such as iridium trichloride hydrate, with 2-phenylpyridine under reflux in an appropriate solvent to form a chloro-bridged dimer intermediate. This is followed by treatment with acetylacetone in the presence of a base, which substitutes chloride ligands with the acetylacetonate ligand, yielding the desired complex as a stable compound.

One of the primary applications of this complex is in the field of organic electronics, particularly as a phosphorescent emitter in organic light-emitting diodes (OLEDs). The complex exhibits strong photoluminescence with high quantum efficiency due to the heavy-atom effect of iridium, which facilitates efficient intersystem crossing to the triplet excited state, enabling phosphorescence at room temperature. The acetylacetonate ligand plays a role in stabilizing the complex and tuning its electronic properties, while the 2-phenylpyridine ligands contribute to the emission wavelength and color.

In addition to OLEDs, acetylacetonatobis(2-phenylpyridine)iridium is investigated for use in photocatalysis, where its ability to absorb visible light and transfer energy or electrons enables a range of chemical transformations under mild conditions. It can act as a sensitizer in photoredox catalysis, promoting reactions such as C–C bond formation, oxidation, and reduction with improved selectivity and efficiency.

The complex is also utilized in sensing applications due to its luminescent properties, where changes in emission intensity or wavelength can indicate the presence of certain analytes or environmental conditions. Its stability and tunable photophysical characteristics make it a versatile candidate for such technologies.

From a structural perspective, acetylacetonatobis(2-phenylpyridine)iridium features strong metal–ligand coordination bonds that confer high thermal and chemical stability, which is essential for device fabrication and catalytic applications. The complex is generally a crystalline solid with good solubility in common organic solvents such as dichloromethane, chloroform, and toluene, facilitating its processing.

Safety considerations when handling this complex include avoiding prolonged exposure and inhalation of dust or vapors, as with many organometallic compounds. Standard laboratory practices such as working in a fume hood and wearing appropriate personal protective equipment are recommended.

In summary, acetylacetonatobis(2-phenylpyridine)iridium is a robust and efficient organoiridium complex with significant applications in organic electronics, photocatalysis, and sensing. Its design combines cyclometalated ligands and a β-diketonate ligand to afford excellent photophysical properties and chemical stability, making it a valuable compound in modern materials science and synthetic chemistry.

References

2011. Spiro-Configured Bipolar Host Materials for Highly Efficient Electrophosphorescent Devices. Chemistry � An Asian Journal, 6(10).
DOI: 10.1002/asia.201100467