title: Vibrational spectrum of m-benzyne: a matrix isolation and computational study.
abstract: m-Benzyne (2) was generated in low-temperature matrices and IR spectroscopically characterized from four different precursors. To assign the IR absorptions, the perdeuterated derivative 2-d(4) was also investigated. By comparison with CCSD(T) calculations all vibrations between 200 and 2500 cm(-)(1) with a predicted relative intensity >2% could be assigned. All experimental and theoretical results are in accordance with a biradicaloid structure for 2, while there is no evidence for a bicyclic closed-shell structure. While benzyne 2 is stable under the conditions of matrix isolation at low temperature, flash vacuum pyrolysis at high temperatures or UV irradiation results in the rearrangement to cis-enediyne. A mechanism involving ring opening accompanied by hydrogen migration is proposed.
authors.affiliation: Lehrstuhl für Organische Chemie II der Ruhr-Universität, D-44780 Bochum, Germany.
authors.forename: Wolfram
authors.initials: W
authors.lastname: Sander
authors.forename: Michael
authors.initials: M
authors.lastname: Exner
authors.forename: Michael
authors.initials: M
authors.lastname: Winkler
authors.forename: Andreas
authors.initials: A
authors.lastname: Balster
authors.forename: Angelica
authors.initials: A
authors.lastname: Hjerpe
authors.forename: Elfi
authors.initials: E
authors.lastname: Kraka
authors.forename: Dieter
authors.initials: D
authors.lastname: Cremer