75749-92-7Relevant articles and documents
Intermediacy of ion neutral complexes in the fragmentation of short-chain dialkyl sulfides
Filsak,Budzikiewicz
, p. 601 - 610 (2007/10/03)
The main fragmentation processes after electron ionization of butyl methyl and butyl ethyl sulfides are rationalized by the intermediacy of the ion neutral complex [RSH · methylcyclopropane](+·) as demonstrated by extensive labeling and collision activation studies.
The Thermal Ring Opening of 3,3-Disubstituted Cyclobutenes
Curry, Michael J.,Stevens, Ian D. R.
, p. 1391 - 1398 (2007/10/02)
The rates of the thermal unimolecular isomerisation of 3-t-butyl-3-methylcyclobutene and 3-methyl-3-phenylcyclobutene have been measured in the gas phase over the temperature ranges 158-190 deg C and 120-180 deg C, respectively.They are correlated by the Arrhenius expressions k = 1014.08 +/- 0.30exp(-150.8 +/- 2.5/RT) s-1 and k = 1012.50 +/- 0.12exp(-126.15 +/- 0.95/RT) s-1, respectively.The ratio of Z- to E-isomer of the butadienes formed has been measured both for these two and for the 3-methyl-3-R-cyclobutenes, where R = isopropyl, n-propyl, cyclopropyl, pentadeuterioethyl, 4-methoxyphenyl, 3-methoxyphenyl, and 4-cyanophenyl.In each case the proportion of Z-isomer formed is much larger than would be predicted on steric grounds.For the aryl compounds an attractive interaction during the formation of the Z-diene is proposed to account for its excess formation.For the alkyl substituents, a repulsive electronic interaction between the group and the developing remote double bond should be larger for methyl than for the other alkyl groups, accounting for the observed product ratios.The rates of isomerization of the 3-aryl-3-methylcyclobutenes at 161 deg C correlate with the LUMO of the aromatic ring.The conclusions are shown to apply to results which have been reported by other authors.
