0000000000030861

AUTHOR

Hermann Rau

showing 2 related works from this author

Photokinetic examination of (Z,E,E)-4,4′-distyrylazobenzene

1995

Abstract 4,4′-Distyrylazobenzenes demonstrate a photokinetic equilibrium and a superimposed thermal backward reaction in which the absorption coefficient of one of the partners in the equilibrium is principally unknown. Using the dependence of the photostationary state on the irradiation intensity, the photochemical quantum yields ϕ 1 A and ϕ 2 B were determined, as well as the thermal rate constant k , as a function of the irradiation and observation wavelengths. Experimental difficulties and the wavelength dependence of ϕ 1 A and ϕ 2 B are discussed.

business.industryChemistryGeneral Chemical EngineeringGeneral Physics and AstronomyQuantum yieldGeneral ChemistryMolecular electronic transitionWavelengthOpticsReaction rate constantPhotostationary stateAttenuation coefficientAbsorptanceIrradiationAtomic physicsbusinessJournal of Photochemistry and Photobiology A: Chemistry
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4,4′‐Distyrylazobenzol als Chromophor

1992

4,4′-Distyrylazobenzene as Chromophore 4,4′-Distyrylazobenzenes are prepared from 4,4′-dimethylazobenzene. Whereas the Siegrist method furnishes stereoselectively the (E,E,E) configuration, a Wittig olefination leads to a mixture of (Z,E,Z), (Z,E,E) and (E,E,E) isomers which can be easily separated. Irradiation of the intense absorption at λ ≈ 400 nm causes a selective (E) (Z) isomerization of the N = N bond of all three isomers. The reverse reaction takes part in the photochemical equilibration, moreover, it is a thermal process with a relatively low activation barrier.

Inorganic Chemistrychemistry.chemical_compoundAzo compoundchemistryWittig reactionStereoselectivityIrradiationAbsorption (chemistry)ChromophorePhotochemistryMedicinal chemistryIsomerizationReversible reactionChemische Berichte
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