Uv photoelectron spectrum of o-xylylene — detection of a low-energy non-koopmans (shake-up) ionization

Direct Observation of para-Xylylene as the Decomposition Product of the meta-Xylyl Radical Using VUV Synchrotron Radiation

“…It is apparent that this pyrolysis product is not the m -xylylene diradical, which has a calculated adiabatic IE of 7.29 eV . Comparison with literature adiabatic IEs of the other C 8 H 8 isomers o -xylylene (7.70 eV), styrene (8.464 eV), p -xylylene (7.87 eV), and benzocylobutene (8.66 eV), confirms undoubtedly that p -xylylene is detected and that this is a product of m -xylyl decomposition. In order to further substantiate this assignment, the structure of the TPE spectrum was simulated by a FC analysis, showing mostly an activity of C–C–C bending and C–C stretching vibrations.…”

o-Quinodimethanes: Efficient Intermediates in Organic Synthesis

“…These species are particularly interesting provided that [4 + 2] cycloadditions of the Diels-Alder type are accelerated dramatically by the oxidation of one of the reactants to the radical cation. 33 Thus, reactions of oQDM radical cations (18) with alkenes are particularly well suited for the study of [3π + 2π] radical cation-mediated reactions considering that the ionization energy (IE) of oQDM (7.70 eV 34 ) is sufficiently well below the IE of alkenes to prevent charge exchange from competing radical cationmediated reactions. Gru ¨tzmacher and Barkow have studied ion-molecule reactions of oQDM +• ions (from EI-induced loss of water from 2-methylbenzyl alcohol, 17) and different alkenes by using FT-ICR 35 (Fourier transform-ion cyclotron resonance) spectrometry (Scheme 6).…”

“…Alternatively, Lenihan and Shechter have developed a methodology to obtain substituted oQDM by 1,4-elimination of R,R-disubstituted silyl sulfones (34) with tetrabutylammonium fluoride (TBAF, Scheme 14). 57 It has proved to be a mild and efficient method for generating substituted oQDM.…”

Surprisingly small effect of an .alpha.-trifluromethyl-for-.alpha.-methyl substitution on 1-(4-methoxyphenyl)ethyl cation reactivity

“…Jencks, W. P. Catalysis in Chemistry and Enzymology; McGraw Hill: New York, 1969; p 571. (7) Compound 4 was synthesized by bromination of the precursor alcohol with 3µ and purified by vacuum distillation. The NMR, IR, and elemental analysis are in agreement with the chemical structure.…”