# H/D exchange under mild conditions in arenes and unactivated alkanes with CDand DO using rigid, electron-rich iridium PCP pincer complexes.
> 電子豊富なイリジウムPCPピンセット錯体を用いた穏和条件下でのアレーンおよび非活性化アルカンのH/D交換反応


## Abstract

An iridium polyhydride complex bearing an electron-rich PCP pincer ligand was synthesized and fully characterized. At room temperature, the complex readily releases molecular hydrogen, enabling rapid hydrogen isotope exchange (HIE) at hydridic and α-C-H positions with deuterated solvents. Sequential loss of one or two equivalents of H2 generates unsaturated iridium carbene trihydride or monohydride intermediates capable of reversible hydride transfer to the carbene carbon, creating additional coordinative unsaturation. These intermediates function as highly active HIE catalysts using CD4 or D2O as deuterium sources, enabling deuteration of diverse substrates including arenes and unactivated alkanes. Reaction conditions can be tuned to achieve either exhaustive or sterically selective deuteration. Preparative-scale deuterations afforded target compounds with greater than 95% deuterium incorporation in excellent isolated yields. The catalyst is recoverable and remains active after regeneration by treatment with H2.

### Mechanism

The iridium PCP pincer complex releases H2 to form unsaturated carbene intermediates that undergo reversible oxidative addition and reductive elimination at substrate C-H bonds, using CD4 or D2O as deuterium sources to catalyze hydrogen isotope exchange.

## Bibliographic

- **Authors**: Smith JD, Durrant G, Ess DH, Gelfand BS, Piers WE
- **Journal**: Chem Sci
- **Year**: 2020 (2020-06-16)
- **PMID**: [34094323](https://pubmed.ncbi.nlm.nih.gov/34094323/)
- **DOI**: [10.1039/d0sc02694h](https://doi.org/10.1039/d0sc02694h)
- **PMC**: [PMC8162389](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8162389/)
- **Study type**: other
- **Delivery route**: in vitro
- **Effect reported**: not assessed

## Delivery context

This is basic research at the cellular or molecular level. For human application, inhalation is the most promising delivery route, but inhalation carries explosion risk and concentration matters (empirical LFL of 10%; high-concentration devices are not recommended).

## Safety notes

This is basic research at the cellular or molecular level. For human application, inhalation is the most promising delivery route, but inhalation carries explosion risk and concentration matters (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)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 34094323. https://h2-papers.org/en/papers/34094323
> **Source**: PubMed PMID [34094323](https://pubmed.ncbi.nlm.nih.gov/34094323/)