0000000000030862
AUTHOR
Günter Gauglitz
showing 3 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.
Kinetische Untersuchungen zu Diels‐Alder‐Reaktionen des Cyclooctins mit anschließender Aromatisierung
1984
Aus Cyclooctin (1) und den cyclischen Dienen 2a – g entstehen die Tricyclen 3a – g, die ganz unterschiedliche Stabilitat aufweisen. 3a, b, f und g zerfallen spontan. Unter Abspaltung von CO2, SO2, CO und N2 entstehen die aromatischen Verbindungen 4a – c. 3c eliminiert beim Erhitzen C2H4. 3e wird thermisch kaum mehr gespalten, aber ganz effizient bei der Photolyse, und 3d ist schlieslich gegenuber einer Aromatisierung stabil. Die thermische Ethylenabspaltung und die doppelte Photodecarbonylierung werden kinetisch untersucht. Kinetic Investigations of Diels-Alder-Reactions of Cyclooctyne with Consecutive Aromatization The tricyclic compounds 3a – g, generated from cyclooctyne (1) and the cycl…
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.