- (1) University of Southern Denmark, grid.10825.3e, SDU
- (2) National University of Singapore, grid.4280.e
- (3) RIKEN Center for Emergent Matter Science, grid.474689.0
- (4) University of Mons, grid.8364.9
The neutral ethenediselone, Se=C=C=Se, has been characterised by neutralisation–reionisation mass spectrometry, which implies a minimum lifetime of the order of microseconds. Tetraselenafulvalene 1 and tetramethyltetraselenafulvalene 2 were used as precursor molecules. Flash vacuum thermolysis (FVT) of these compounds with isolation of the products in Ar matrices permitted the identification of ethyne, 2-butyne, CSe2, and selenoketene, H2C=C=Se, but at best traces of Se=C=C=Se survived the FVT/matrix isolation experiment. Multiconfigurational calculations indicate that Se=C=C=Se is a ground state triplet molecule with a very small singlet-triplet gap.