A systematic investigation of electron abstraction reactions of triplet duroquinone (DQT) has been carried out. A 347.1-nm laser photolysis technique combined with fast conductance measurements and kinetic spectroscopy were used to monitor its reactions with various donor molecules (D). In mixtures of water/ethanol (2:1 v/v) DQT abstracts electrons from a variety of substrates such as Fe2+, Fe(CN)64-, CO32-, diphenylamine, and 1,3,5-trimethoxybenzene. Thereby durosemiquinone (DQ") and oxidized donor (D+) is formed. The rate constants for these redox processes are close to the diffusion-controlled limit (109-10m M_l s_1) except for D = CO32-, where k = 7 X 107 M_l s_l. With all donors conversion of DQT into DQ" was quantitative. DQT in the H20/EtOH mixture also abstracts electrons from ethanol itself. This quenching reaction occurs at a relatively slow rate and yields only ca. 20% DQ".

Ahstir(ltionss(lakrren, sidirhuv und ulrr~i~iolerr Fwit, Rorfikale 1 PhorochPmk3-nitropyrene was exposed to a 347.2 nm laser flash in dilute solutions of organic solvents and in aqueous micellar solutions. It was found that the triplet state is formed with a quantum yield of 0.6. The triplet absorption spectrum shows a red shift with increasing polarity of the solvent. Triplet-triplet energy transfer experiments with anthracene, pyrene and perylene were performed to obtain both the energy (190 & 10 kJ/mol) and the absolute extinction coefficient ((1.0 f 0.1) lo4 M -' cm-' at 530 nm in benzene) of the 3-nitropyrene triplet. Diffusion-controlled triplet-triplet annihilation occurs in ethanol, benzene and hexane solutions. In some micellar solutions and in glycerol, where the bimolecular triplet-triplet interaction is retarded, the triplet was found to disappear in a first order process with a half lifetime of 230 ps. -The triplet state of 3-nitropyrene abstracts a hydrogen atom from diphenylamine with k = 2.9. lo9 M -' s-'. Electron abstraction from Fez+ and CO:-, which should be possible from the point of energetics, could not be observed. 3-Nitropyren wurde in verschiedenen organischenLosungsmitteln und in waDrigen mizellaren Losungen mit einein 347,2 nm-Blitz eines Lasers bestrahlt. Der Triplettzustand wird init einer Quantenausbeute von O,6 gebildet. Sein Absorptionsspektrum zeigt eine Rotverschiebung in Losungsmitteln hoherer Polaritat. Experimente zur Triplett-Triplett-Energieubertragung mit Anthrazen, Pyren und Perylen lieferten die Energie (190 k 10 kJ/mol) und den absoluten Extinktionskoeffizienten ((1,O f 0,l) lo4 M -' cm-' b el ' 530 nm in Benzol) des 3-Nitropyren-Tripletts. Die Triplett-Triplett-Loschung geschieht diffusions-kontrolliert in Athanol, BenzoI nnd Hexan. In einigen mizellaren Losungen sowie in Glycerol, wo die bimolekulare Triplett-Triplett-Wechselwirkung verzogert ist, verschwindet das Triplett nach erster Ordnung mit einer Halbwertszeit von 230 vs. -Der Triplett-Zustand des 3-Nitropyrens abstrahiert ein H-Atom von Diphenylamin mit k = 2 . 9 . 1 0 9~-' s -~ . Elektronen-Aufnahme aus Fez+ und COi-, die in energetischer Hinsicht inoglich sein sollte, wurde nicht beobachtet.

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In einer laserphotolytischen Untersuchung wird gezeigt, daß CO32‐‐Anionen in wäßrigen Lösungen von Dodecyltrimethylammoniumchloridmizellen in der sehr schnellen Reaktion A (<15 ns) durch Durochinon‐Tripletts (DQT) oxidiert werden.

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