Emil Karaev, Dorothee Schaffner, Marius Gerlach, Tobias Preitschopf, Patrick Hemberger, Ingo Fischer
{"title":"Threshold Photoelectron Spectrum of 3,4-Dimethylenecyclobutene","authors":"Emil Karaev, Dorothee Schaffner, Marius Gerlach, Tobias Preitschopf, Patrick Hemberger, Ingo Fischer","doi":"10.1002/hlca.202400197","DOIUrl":null,"url":null,"abstract":"<p>We report a study on the photoionization of the C<sub>6</sub>H<sub>6</sub> isomer 3,4-dimethylenecyclobutene, DMCB. The molecule is an intermediate in the formation of benzene from the propargyl radical self-reaction, a suggested first step in the formation of polycyclic aromatic hydrocarbons and soot. From a threshold photoelectron spectrum we determine an adiabatic ionization energy of 8.75 eV. The geometry change upon ionization is associated with considerable vibrational activity, which is assigned to a symmetric in-plane bending mode of the =CH<sub>2</sub> groups. A breakdown diagram shows that the dissociative photoionization resembles the one observed for benzene. Computations reveal that DMCB cation isomerizes to the benzene cation and dissociates from there.</p>","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"108 3","pages":""},"PeriodicalIF":1.5000,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202400197","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Helvetica Chimica Acta","FirstCategoryId":"92","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/hlca.202400197","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
We report a study on the photoionization of the C6H6 isomer 3,4-dimethylenecyclobutene, DMCB. The molecule is an intermediate in the formation of benzene from the propargyl radical self-reaction, a suggested first step in the formation of polycyclic aromatic hydrocarbons and soot. From a threshold photoelectron spectrum we determine an adiabatic ionization energy of 8.75 eV. The geometry change upon ionization is associated with considerable vibrational activity, which is assigned to a symmetric in-plane bending mode of the =CH2 groups. A breakdown diagram shows that the dissociative photoionization resembles the one observed for benzene. Computations reveal that DMCB cation isomerizes to the benzene cation and dissociates from there.
期刊介绍:
Helvetica Chimica Acta, founded by the Swiss Chemical Society in 1917, is a monthly multidisciplinary journal dedicated to the dissemination of knowledge in all disciplines of chemistry (organic, inorganic, physical, technical, theoretical and analytical chemistry) as well as research at the interface with other sciences, where molecular aspects are key to the findings. Helvetica Chimica Acta is committed to the publication of original, high quality papers at the frontier of scientific research. All contributions will be peer reviewed with the highest possible standards and published within 3 months of receipt, with no restriction on the length of the papers and in full color.