Characterization of C₂S₄^·+ isomers by mass spectrometry and ab initio molecular orbital calculations

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• 作者：Gerbauxa ; Pascal ; Flammanga ; Robert ; et. al.
• 关键词：Mass spectrometry ; Collisional activation ; Neutralization&ndash ; reionization ; Ion/molecule reactions ; C₂S₄ radical cations
• 刊名：International Journal of Mass Spectrometry
• 出版年：2001
• 出版时间：September 14, 2001
• 年：2001
• 卷：210-211
• 期：Complete
• 页码：31-42
• 全文大小：206 K

文摘

Isomeric C₂S₄^·+ radical cations, a dimer (CS₂)CS₂^·+ and a covalently bounded C₂S₄^·+ species, are generated by chemical ionization (self-chemical ionization conditions) of carbon disulfide or by dissociative electron ionization of 1,3,4,6-tetrathiapentalene-2,5-dione and 1,2-dithiolo[4,3-c][1,2]dithiole-3,6-dione, respectively. These ions are structurally characterized making use of mass spectrometric methodologies such as collisional activation, neutralization–reionization and ion–molecule reactions performed in a hybrid tandem mass spectrometer of sector–quadrupole–sector configuration. These experimental results are supported by ab initio calculations of the relative energies of 19 possible isomers indicating that the most stable C₂S₄^·+ structure corresponds to a CS₂ dimer with a C₂ symmetry, 52 kJ mol⁻¹ more stable than the lowest-energy covalently bound structure consisting of a four-membered ring thioketene species.