Gasphasen‐Reaktionen, 30. Thioacrolein: Das stabilste C ₃ H ₄ S‐Isomere und sein PE‐spektroskopischer Nachweis in der Gasphase

Das Ensemble C3H4S enthalt 13 valenz-„normale” Isomere, unter denen nach MNDO-Berechnungen Thioacrolein, H2CC(H)(H)CS, das energetisch stabilste sein sollte. Erwartungsgemas zerfallt Diallylsulfid bei 660K-Pyrolyse zu Propen und Thioacrolein, welches sich in einer Ausfrierfalle praparativ als Diels-Alder-Dimerengemisch abfangen last. Erhitzen der isomeren Dimeren fuhrt unter Retrodien-Spaltung zu reinem Thioacrolein, das sich durch sein dem Acrolein ahnliches PE-Spektrum identifizieren last. Gas Phase Reactions, 30. Thioacrolein: The Most Stable Isomer C3H4S and its PE Spectroscopic Proof in the Gas Phase The ensemble C3H4S contains 13 valence-„normal” isomers, of which according to MNDO calculations thioacrolein, H2CC(H)(H)CS, should be the energetically most stable. Expectedly, diallyl sulfide decomposes on pyrolysis at 660 K to yield propene and thioacrolein, which can be cool-trapped in a preparative way as mixture of Diels-Alder dimers. Heating of the isomeric dimers leads in a retrodiene splitting to pure thioacrolein, identified by its PE spectrum which is similar to that of acrolein.