# Insertion of Unsaturated C-C Bonds into the O-H Bond of an Iridium(III)-Hydroxo Complex: Formation of Phosphorescent Emitters with an Asymmetrical β-Diketonate Ligand.
> イリジウム(III)ヒドロキソ錯体のO-H結合への不飽和C-C結合挿入による非対称β-ジケトナート配位子を持つリン光発光体の合成


## Abstract

A new synthetic route to iridium(III) phosphorescent complexes of the [3b+3b+3b'] class, incorporating two cyclometalated 1-phenylisoquinoline units and an asymmetric β-diketonate ligand, was established. Starting from a chloride-bridged dimer, chloride abstraction with AgBF4 in acetone followed by water addition yielded a mononuclear water solvate. Subsequent treatment with KOH produced a dihydroxo-bridged dimer, which upon reaction with dimethyl acetylenedicarboxylate or α,β-unsaturated ketones underwent O-H bond addition across C-C triple or double bonds, respectively, generating asymmetric β-diketonate chelates. In the case of α,β-unsaturated ketones, molecular hydrogen loss drove aromatization of the chelate ring. The resulting complexes exhibited red-region phosphorescence (599–672 nm) in doped PMMA films (5 wt%) and in 2-methyltetrahydrofuran at room temperature and 77 K, with emission lifetimes of 0.8–2.5 μs and quantum yields ranging from approximately 0.35 to 0.6 depending on β-diketonate substitution.

### Mechanism

The O-H bond of a mononuclear iridium hydroxo fragment adds across C-C triple bonds of alkynes or C-C double bonds of α,β-unsaturated ketones; subsequent carbonyl coordination to iridium and loss of molecular hydrogen drives aromatization to form asymmetric β-diketonate chelate ligands.

## Bibliographic

- **Authors**: Boudreault PT, Esteruelas MA, López A, Oñate E, Raga E, Tsai JY
- **Journal**: Inorg Chem
- **Year**: 2020 (2020-11-02)
- **PMID**: [33059453](https://pubmed.ncbi.nlm.nih.gov/33059453/)
- **DOI**: [10.1021/acs.inorgchem.0c02395](https://doi.org/10.1021/acs.inorgchem.0c02395)
- **Study type**: other
- **Delivery route**: not specified
- **Effect reported**: not assessed

## Delivery context

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

## Safety notes

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)

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> **Cite as**: H2 Papers — PMID 33059453. https://h2-papers.org/en/papers/33059453
> **Source**: PubMed PMID [33059453](https://pubmed.ncbi.nlm.nih.gov/33059453/)