Premium
C—H bond energy of the triphenylene radical cation: a photoionization mass spectrometry study
Author(s) -
Ling Yun,
Lifshitz Chava
Publication year - 1997
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199711)32:11<1219::aid-jms581>3.0.co;2-m
Subject(s) - triphenylene , chemistry , photoionization , mass spectrometry , bond energy , radical ion , computational chemistry , ion , organic chemistry , molecule , chromatography , ionization
Unimolecular fragmentations of the triphenylene radical cation were studied by photoionization mass spectrometry in the vacuum UV region and by RRKM/QET calculations. The vibrational frequencies of the triphenylene neutral and its radical cation were calculated by density functional theory. The major reactions observed were parallel H • and H 2 losses. Activation parameters were deduced for the reactions. The H • loss reaction is characterized by a loose transition state, whereas the H 2 elimination has a much tighter transition state. The following heats of formation were deduced: Δ H f0 °([C 18 H 11 ] + )=1202.9±20 kJ mol ‐1 , Δ H f0 °([C 18 H 10 ] + • )=1397.7±20 kJ mol ‐1 . The C—H bond dissociation energy in the triphenylene radical cation is 3.73±0.2 eV (359.9±20 kJ mol ‐1 ). The effect of the triphenylene structure on the C—H bond dissociation energy deduced for the triphenylene radical cation is discussed. © 1997 John Wiley & Sons, Ltd.