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MO: Fachverband Molekülphysik

MO 24: Large and Reactive Systems

MO 24.5: Vortrag

Freitag, 15. März 2019, 11:30–11:45, S HS 002 Biologie

Joining Microfluidics with Infrared Photodissociation: Shedding Light on ortho-Quinone Methides, a Highly Reactive and Transient Intermediate — •Martin Mayer, Max Grellmann, and Knut R. Asmis — Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstrasse 2, D-04103 Leipzig, Germany

Chemical microreactors, such as microfluidic chips, are revolutionizing the way we can study chemical reactions by making time scales available that were not reachable with conventional techniques. Here, we combine microfluidic chips with the structure determining power of infrared photodissociation (IRPD) spectroscopy to shed light on the in-situ formation of ortho-quinone methides (o-QM). Those highly reactive, transient and therefore not isolatable intermediates occur in innumerable natural processes and have a huge potential in organic synthesis, especially regarding stereoselective reactions. The ephemerality of o-QMs often prevents their investigation by conventional analytical methods. By coupling microfluidics with IRPD spectroscopy, we are not only able to characterize the structures, but also determine E/Z ratios of o-QMs which are produced in-situ on chip. This information is given by the analysis of the IR fingerprint regions of the short-lived species. Control over stereoselectivity is achieved by introducing lewis acidic alkali metal ions into the reactions and monitoring stereoisomer-selective IR absorption bands which reflect the resulting E/Z ratio. With this multidimensional approach we are able to gain a deeper understanding and control over the formation of elusive o-QMs.