'Triplet-Triplet Absorption Spectra

Acetophenone

Alfimov, M.V.; Buben, N.Ya.; Glagolev, V.L.; Kuyumdzhi, E.S.; Pomazan, Yu.V.; Shamshev, V.N.
Triplet-triplet absorption of some carbonyl-containing compounds.
Opt. Spectrosc. 42: 267-70 (1977)

Acetophenone
Solvent : ?, 81 K

wave length (nm) at maximum, extinction coefficient = 330, 1300

Triplet state population method: Flash photolysis
Extinction coefficient estimation method: Singlet depletion
Lifetime = (1 ± 0.1) x 10⁴ micro sec.
Comments: ^*Phosphorescence decay; glass was either 1:3:3 1-methylPrOH to Et₂O to isooctane or 1:9 MCH to mixture of EtOH and MeOH

Lutz, H.; Breheret, E.; Lindqvist, L.
Effects of solvent and substituents on the absorption spectra of triplet acetophenone and the acetophenone ketyl radical studied by nanosecond laser photolysis.
J. Phys. Chem. 77: 1758-62 (1973)

Acetophenone
Solvent : Acetonitrile

wave length (nm) at maximum, extinction coefficient = 320^a, 12600^a

Triplet state population method: Pulsed laser photolysis
Extinction coefficient estimation method: Relative actinometry
Comments: epsilon relative to benzophenone in cyclohexane (epsilon₅₃₃ = 7630 L mol^–1 cm^–1, assuming no solvent effect from benzene), and taking all the triplet yields to be unity

Lutz, H.; Lindqvist, L.
Nanosecond laser photolysis of acetophenone in organic solvents.
J. Chem. Soc. D : 493-4 (1971)

Acetophenone
Solvent : Cyclohexane

wave length (nm) at maximum, extinction coefficient = 449^a, 1800^a

406^a, 2100^a

Triplet state population method: Pulsed laser photolysis
Extinction coefficient estimation method: Energy transfer
Lifetime = 0.23 micro sec.
Comments: ^*Oxygen quenching, triplet ET to naphthalene, and quenching by piperylene; epsilon relative to naphthalene in cyclohexane (epsilon_412.5 = 22600 L mol^–1 cm^–1)

Acetophenone
Solvent : Cyclohexane

wave length (nm) at maximum, extinction coefficient = 441^a, 1900^a

401^a, 2100^a

Lutz, H.; Lindqvist, L.
Nanosecond laser photolysis of acetophenone in organic solvents.
J. Chem. Soc. D : 493-4 (1971)

Acetophenone
Solvent : EtOH

wave length (nm) at maximum, extinction coefficient = 323^a, 6300^a

Triplet state population method: Pulsed laser photolysis
Extinction coefficient estimation method: Energy transfer and relative actinometry
Lifetime = 0.14 micro sec.
Comments: epsilon relative to naphthalene in cyclohexane (epsilon_412.5 = 22600 L mol^–1 cm^–1), assuming no solvent effects, for ET method; epsilon relative to benzophenone in benzene (epsilon_532.5 = 10300 L mol^–1 cm^–1), assuming no solvent effects and taking Phi_T(acetophenone) = 1 = Phi_T(benzophenone), and epsilon relative to benz[a]anthracene in cyclohexane (epsilon₄₈₀ = 25100 L mol^–1 cm^–1), assuming no solvent effects and taking Phi_T(acetophenone) = 1 and Phi_T(benz[a]anthracene) = 0.82, for RA method; there was a shoulder at ~495^a nm.

Porter, G.; Windsor, M.W.
The triplet state in fluid media.
Proc. R. Soc. London, Ser. A 245: 238-58 (1958)

Acetophenone
Solvent : Liquid paraffin

wave length at maximum = 281.5; 265 nm

Triplet state population method: Flash photolysis
Comments: Solvent viscosity was 0.03 N•s/m²

Ledger, M.B.; Porter, G.
Primary photochemical processes in aromatic molecules. Part 15. The photochemistry of aromatic carbonyl compounds in aqueous solution.
J. Chem. Soc., Faraday Trans. 1 68: 539-53 (1972)

Acetophenone
Solvent : Water

wave length at maximum = 335 nm

Triplet state population method: Flash photolysis
Lifetime = ~100 micro sec.

Acetophenone
Solvent : Water

wave length (nm) at maximum, extinction coefficient = 337^a, 13100^a

^* Evidence supporting the assignment of the transient triplet state.
^a Data have been obtained by computer-assisted digitization from spectrum in cited reference.
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wave length (nm) at maximum, extinction coefficient =	449^a, 1800^a
	406^a, 2100^a

wave length (nm) at maximum, extinction coefficient =	441^a, 1900^a
	401^a, 2100^a