Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, LMU München, Oettingenstr. 67, D-80538 München, Germany.
Phys Chem Chem Phys. 2009 Dec 28;11(48):11596-607. doi: 10.1039/b915451e. Epub 2009 Nov 5.
The formation and decay of a ketene intermediate photochemically formed from o-nitrobenzaldehyde has been studied by femtosecond UV/Vis and IR spectroscopy. The ketene is formed predominantly within a few 100 fs and to a minor extent within approximately 200 ps via the recombination of a triplet phased bi-radical. In tetrahydrofuran solution the ketene intermediate is seen to form a secondary intermediate with biphasic kinetics. The first phase of this decay occurs within a few picoseconds. It can be attributed to the reaction of vibrationally excited ketenes. The second phase characterized by a time constant of 2 ns is due to the reaction of thermalized molecules. In 2-butanol solution the lifetime of the thermalized ketene is only approximately 60 ps and the rapid and the slow phases of the decay start to merge.
通过飞秒紫外/可见和红外光谱研究了邻硝基苯甲醛光化学形成的烯酮中间体的形成和衰减。烯酮主要在几百飞秒内形成，次要地在大约 200 皮秒内通过三重态相双自由基的重组形成。在四氢呋喃溶液中，烯酮中间体被观察到形成具有两相动力学的次级中间体。该衰减的第一阶段在几皮秒内发生。它可以归因于振动激发的烯酮的反应。第二阶段的特征是 2 ns 的时间常数，这是由于热化分子的反应。在 2-丁醇溶液中，热化的烯酮的寿命仅约为 60 皮秒，衰减的快速和缓慢阶段开始合并。
