Photochemistry
Eu(II) cryptate photocatalyzes bibenzyl coupling
Open access · cc by · source: Europe PMC
A visible-absorbing Eu(II) azacryptate, assembled in situ from EuCl3, ligand and Zn0, reductively couples benzyl chloride to 1,2-diphenylethane with an excited-state potential near −3 V.
How this study connects
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A visible-absorbing Eu(II) azacryptate, assembled in situ from EuCl3, ligand and Zn0, reductively couples benzyl chloride to 1,2-diphenylethane with an excited-state potential near −3 V.
Evidence for the claim as stated.
Study at a glance
- Design
- Animal / in-vitro — In situ Eu(II) azacryptate photoredox coupling of benzyl chloride under blue light
- N
- Stoichiometric and 0.5–5 mol% catalytic loadings with photophysical replicates
- Population
- Visible-light reductive coupling in methanol, including wet EuCl3·6H2O conditions
- Outcome
- Eu(II) photoredox gives bibenzyl in 60–85% yield with an excited-state potential near −3 V vs Ag/AgCl
Structured fields used in claim comparison tables when every cited study has a complete layer.
Inspect source passages
Eu(II) cryptate photocatalyzes bibenzyl coupling
These passages occur verbatim in the stored paper text. They support the points listed below; they do not verify every statement in the explanation.
Stoichiometric irradiation gave 85±2% 1,2-diphenylethane within 30 minutes.
We observed the formation of 1,2-diphenylethane (85 ± 2%) and toluene (4.7 ± 0.4%) within 30 minutes ().
At 5, 1, and 0.5% catalyst, bibenzyl yields were 71±5%, 70±5%, and 60±3%.
Yields of 1,2-diphenylethane of 71 ± 5% (∼14 turnovers), 70 ± 5% (∼70 turnovers), and 60 ± 3% (∼120 turnovers), respectively, were observed.
Key findings
Stoichiometric irradiation gave 85±2% bibenzyl in 30 min. Catalytic loadings of 5/1/0.5 mol% gave 71/70/60% bibenzyl (~14–120 turnovers). Excited-state E* ≈ −3.0 V vs Ag/AgCl; τ = 0.98 μs; Φ = 37% in MeOH. The system tolerates some water.
Methodology
Authors encapsulated Eu(II) in octaazacryptand 1, measured absorption/emission, lifetime, quantum yield and electrochemistry, then ran blue-light couplings of benzyl chloride with sacrificial Zn0, including wet EuCl3·6H2O conditions.
Limitations
Scope on unactivated aryl bromides is proposed, not demonstrated; E1/2 was measured in DMF not methanol.
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