40422-15-9Relevant articles and documents
Protonated 1,3,5-cycloheptatriene and 7-alkyl-1,3,5-cycloheptatrienes in the gas phase: Ring contraction to the isomeric alkylbenzenium ions
Mormann, Michael,Kuck, Dietmar
, p. 384 - 394 (2007/10/03)
1,3,5-Cycloheptatriene (1) and various 7-alkyl-1,3,5-cycloheptatrienes (3, 6, 9, 13, and 16-19) were subjected to gas-phase protonation under CI(CH4) and CI(iC4H10) conditions and the MIKE spectra of their [M + H]+ ions were measured. Loss of CH4 from the parent ion [1 + H]+ and almost exclusive loss of C2H4 from the methyl derivative [3 + H]+ indicate ring contraction of the dihydrotopylium ions to protonated toluene (toluenium ions) and protonated ethylbenzene (ethylbenzenium ions), respectively, prior to fragmentation. With increased exothermicity of protonation, ions [3 + H]+ also isomerize to xylenium ions. Similarly, higher protonated n-alkylcycloheptatrienes undergo skeletal isomerization to the corresponding 'chain-elongated' (n + 1)-alkylbenzenium and to the corresponding n-alkyltoluennium ions. Starting with ethyldihydrotropylium ions, a competing isomerization channel is opened giving rise to expulsion of C2H4 from the constituents of the seven-membered ring, as evidenced by deuterium labelling and an unusually high kinetic energy release. Isoalkyl analogues behave in a similar manner with increased hydrogen exchange between the α position of the side chain and the ring.
THE rs STRUCTURES OF PROPYL FLUORIDE AND DIFFERENCES IN STRUCTURES BETWEEN ROTATIONAL ISOMERS
Hayashi, Michiro,Fujitake, Masaharu
, p. 9 - 24 (2007/10/02)
Microwave spectra of trans and gauche propyl fluoride and its isotopically substituted species have been measured.The rs structures of the trans and gauche isomers of this molecule are determined from the observed moments of inertia.It is found that the CCC angle values are largely different between two isomers, while the CCF angle values stay unchanged.The rs structures of ethyl fluorosilane and ethylmethyl sulfide are re-examined in order to compare the results with those of propyl fluoride.The differences in the structural parameter values between the rotational isomers are discussed for the present molecules and the analogous molecules such as ethanethiol and ethaneselenol.
