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van‐der‐Waals‐Komplexe, Intermediate monomolekularer Reaktionen
Author(s) -
Roth Wolfgang R.,
Hunold Frank
Publication year - 1996
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199619961128
Subject(s) - chemistry , van der waals force , radical , thermal decomposition , supercritical fluid , decomposition , oxygen , photochemistry , enthalpy , thermodynamics , molecule , organic chemistry , physics
van der Waals Complexes, Intermediates in Unimolecular Reactions Thermolysis of rac ‐ and meso ‐1,1′,2,2′,3,3′ ‐hexamethyl‐1,1′‐biindenyl and (1 E , 5 E )‐1,3,4,6‐tetraphenyl‐1,5‐hexadiene in supercritical CO 2 in the presence of oxygen allows to identify three types of intermediates, the free radicals ( 2 and 5 ) and the equilibrating complexes I and II consisting of radical pairs. From the oxygen dependence of the trapping and rearrangement rates it is shown, that the complex I is the primary thermolysis product, which in contrast to the complex II does not react with oxygen. The temperature dependance of these rates allows to calculate the enthalpy well of the complex II , which agrees well with predictions of our reaction force field.