Concept · chemistry
Photochemistry
10 studies1 discovery
Photochemistry uses absorbed light to generate excited states, radicals or catalytic redox cycles that thermal reactions cannot reach at the same temperature.
Visible-light photoredox is now core undergraduate organic chemistry, and chain vs closed-cycle behaviour changes how you count photons.
Studies
10
Findings
5
7 supporting · 0 challenging · 0 qualifying citations
Open tensions
1
Currently
What we know
- This library holds 10 empirical chemistry papers on photochemistry with isolated findings, rates or spectra rather than reviews.
- First-generation donor–acceptor Stenhouse adducts with a small N-methyl substituent switch well in chloroform; kinetics split photoisomerisation from cyclisation.
- Cyclometalated Pt(II) complexes trifluoromethylate unactivated alkenes in >82% yield under 450 nm LEDs by oxidatively quenching CF3I.
- Ir(ppy)2(NacNac) photocatalysts with BIH hydrodehalogenate unactivated aryl bromides, chlorides, fluorides, and alkyl bromides, including with green light.
- 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.
Largest unresolved question
Quantum yield, wavelength and quencher identity vary widely; a 'photocatalyst' can be a chain initiator rather than a closed cycle.
Common misconceptions
Photoredox always means one photon per product molecule.
Quantum yields above 1 show product-forming chains, not a closed photocatalytic cycle.
Related
Claim ledger
What the evidence shows
Drawn from 10 studies in this library. Mix labels say which citation roles are present; they are not a strength score. Supports means evidence for a finding; Challenges means evidence against a stated position; Qualifies marks scope.
This library holds 10 empirical chemistry papers on photochemistry with isolated findings, rates or spectra rather than reviews.
- DASA photoswitches work in chloroform if N-methyl
- Platinum photoredox catalysts for trifluoromethylation
- Strongly reducing Ir photoredox on aryl chlorides
Study Role Design N Population Outcome DASA photoswitches work in chloroform if N-methyl Supports OtherSynthesis and photoswitching kinetics/fatigue of DASA photochromes 1–14 Molecular photochrome SAR — no sample N Donor–acceptor Stenhouse adduct photoswitches Photoswitching amplitude, kinetics, and fatigue related to substituents Platinum photoredox catalysts for trifluoromethylation Supports OtherBlue-LED photoredox trifluoromethylation catalyzed by cyclometalated Pt(II) complexes Synthetic photoredox catalysis — no sample N Alkenes and heteroarenes under Pt(II)/CF3I photoredox conditions Trifluoromethylation yields and oxidative-quenching mechanism Strongly reducing Ir photoredox on aryl chlorides Supports Animal / in-vitroIr(ppy)2(NacNac) photoredox hydrodehalogenation with BIH under blue or green LEDs Substrate-scope reactions plus Stern–Volmer and quantum-yield measurements Unactivated aryl bromides, chlorides, fluorides, and alkyl bromides Strongly reducing iridium photosensitizers hydrodehalogenate unactivated substrates, including under green light First-generation donor–acceptor Stenhouse adducts with a small N-methyl substituent switch well in chloroform; kinetics split photoisomerisation from cyclisation.
Cyclometalated Pt(II) complexes trifluoromethylate unactivated alkenes in >82% yield under 450 nm LEDs by oxidatively quenching CF3I.
Ir(ppy)2(NacNac) photocatalysts with BIH hydrodehalogenate unactivated aryl bromides, chlorides, fluorides, and alkyl bromides, including with green light.
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.
Debates
Tensions and limits
Some items are genuine disagreements on the same question. Others mark different assays, populations, or outcomes.
Quantum yield, wavelength and quencher identity vary widely; a 'photocatalyst' can be a chain initiator rather than a closed cycle.
Quantum yield, wavelength and quencher identity vary widely; a 'photocatalyst' can be a chain initiator rather than a closed cycle.
- DASA photoswitches work in chloroform if N-methyl
- Platinum photoredox catalysts for trifluoromethylation
Study Role Design N Population Outcome DASA photoswitches work in chloroform if N-methyl Supports OtherSynthesis and photoswitching kinetics/fatigue of DASA photochromes 1–14 Molecular photochrome SAR — no sample N Donor–acceptor Stenhouse adduct photoswitches Photoswitching amplitude, kinetics, and fatigue related to substituents Platinum photoredox catalysts for trifluoromethylation Supports OtherBlue-LED photoredox trifluoromethylation catalyzed by cyclometalated Pt(II) complexes Synthetic photoredox catalysis — no sample N Alkenes and heteroarenes under Pt(II)/CF3I photoredox conditions Trifluoromethylation yields and oxidative-quenching mechanism
PaperFren reads this as a limit on how far one study travels — different assays, populations, or outcomes — not a forced fight between papers.
Timeline
How understanding moved
Study years are when the paper was published. Evidence edits are dated changes to this page's claims. Explanations are when PaperFren added a Discovery — not a claim that the science happened that day.
2026
Concept page published
Photochemistry
- Quantum yields of 44 and 77 say these photoredox reactions run radical chains
Change log
What changed
Dated edits to this page's evidence: studies added or removed from a claim, claims added or withdrawn, and new explanations tagged here. Coverage edits are distinct from reviewed research changes and corrections. Dates record PaperFren updates; study publication dates appear in the timeline.
- Quantum yields of 44 and 77 say these photoredox reactions run radical chainsEvidence: Strengthening
- Coverage updated · Concept page published
Papers
10 studies in this library bear on Photochemistry, ordered by citations.
- Photoredox reactions that run as radical chains
Quantum yields of 44, 77, and 18 show product-forming chains—not a closed photocatalytic cycle of Φ ≤ 1—in three visible-light reactions.
- PQ and water oxy-trifluoromethylate enynes
Sunlight-excited phenanthrenequinone turns Langlois’ CF3SO2Na into CF3· and uses water as the oxygen atom to build CF3 benzofurans, benzothiophenes and indoles.
- Platinum photoredox catalysts for trifluoromethylation
Cyclometalated Pt(II) complexes trifluoromethylate unactivated alkenes in >82% yield under 450 nm LEDs by oxidatively quenching CF3I.
- DASA photoswitches work in chloroform if N-methyl
First-generation donor–acceptor Stenhouse adducts with a small N-methyl substituent switch well in chloroform; kinetics split photoisomerisation from cyclisation.
- Strongly reducing Ir photoredox on aryl chlorides
Ir(ppy)2(NacNac) photocatalysts with BIH hydrodehalogenate unactivated aryl bromides, chlorides, fluorides, and alkyl bromides, including with green light.
- Green-light ATRP that tolerates open air
Eosin Y plus a copper ATRP catalyst polymerizes OEOMA under green light in open vials, giving low dispersity even at 1000 rpm stirring.
- Eu(II) cryptate photocatalyzes bibenzyl coupling
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.
- ML and high-throughput screens find organic H2 photocatalysts
Screening 572 then 96 organic molecules under identical HER conditions, plus ML, uncovered unexpected molecular photocatalysts rivaling conjugated polymers.
Show 2 more studiesShow fewer studies
- Benzaldehyde photoredox heteroarylates amides and ethers
Household CFL light plus benzaldehyde and APS couples heteroarene C–H bonds to amide/ether α-C–H positions without a metal photocatalyst.
- Slow photogenerated Rh–H prefers aldehydes
Proflavine plus a Cp*Rh mediator makes dilute Rh(III)–H that reduces aldehydes while ketones wait, unlike fast formate hydride transfer.
Compare studies
Select 2–10 studies. Design and N are labels, not a ranking.
Nothing selected yet.
Questions
What is still open
Quantum yield, wavelength and quencher identity vary widely; a 'photocatalyst' can be a chain initiator rather than a closed cycle.
Ask PaperFren about Photochemistry
Study this conceptflashcards and short-answer questions
What does photochemistry mean in this chemistry library?
Photochemistry uses absorbed light to generate excited states, radicals or catalytic redox cycles that thermal reactions cannot reach at the same temperature.
Name one empirical finding from the photochemistry papers.
First-generation donor–acceptor Stenhouse adducts with a small N-methyl substituent switch well in chloroform; kinetics split photoisomerisation from cyclisation.
What is a limit of photochemistry evidence here?
Quantum yield, wavelength and quencher identity vary widely; a 'photocatalyst' can be a chain initiator rather than a closed cycle.