The permethylcyclosilanes I [R = Me (II), R2 = SiMe2SiMe2 (III)], IV and V, all of which exhibit low 1st ionization potentials, were oxidized with AlCl3 in CH2Cl2 to form the 1st examples of delocalized, s-electron radical cations, which were studied by ESR spectroscopy. Unlike the well-known radical anion of II, the radical cation gives an ESR spectrum which can be simulated only by assuming 2 sets of 18 equiv. protons, corresponding to 6 axial and 6 equatorial Me groups which do not become equiv. on the ESR time scale. The high g value of 2.0093 obsd. for the radical cation suggests a considerable spin population in the Si6 ring skeleton. The radical cations of III, IV and V show only overlapping signals in the ESR, but their resp. g values of 2.010, 2.0105 and 2.0063 are also consistent with spin delocalization into the sSi-Si system. [on SciFinder(R)]
%0 Journal Article
%1 Bock.1979
%A Bock, H.
%A Kaim, W.
%A Kira, M.
%A West, R.
%D 1979
%J Journal of the American Chemical Society
%K ESR ESR;ionization ESR;photoelectron MO;oxidn cyclopentasilane cyclopoly cyclopolysilane deriv;silane permethyl permethylcyclopolysilane permethylcyclopolysilane;permethylcyclopolysilane potential radical spectrum
%N 26
%P 7667--7670
%R 10.1021/ja00520a006
%T Novel organosilicon radical cations. One-electron oxidation of permethylcyclopolysilanes
%V 101
%X The permethylcyclosilanes I [R = Me (II), R2 = SiMe2SiMe2 (III)], IV and V, all of which exhibit low 1st ionization potentials, were oxidized with AlCl3 in CH2Cl2 to form the 1st examples of delocalized, s-electron radical cations, which were studied by ESR spectroscopy. Unlike the well-known radical anion of II, the radical cation gives an ESR spectrum which can be simulated only by assuming 2 sets of 18 equiv. protons, corresponding to 6 axial and 6 equatorial Me groups which do not become equiv. on the ESR time scale. The high g value of 2.0093 obsd. for the radical cation suggests a considerable spin population in the Si6 ring skeleton. The radical cations of III, IV and V show only overlapping signals in the ESR, but their resp. g values of 2.010, 2.0105 and 2.0063 are also consistent with spin delocalization into the sSi-Si system. [on SciFinder(R)]
@article{Bock.1979,
abstract = {The permethylcyclosilanes I [R = Me (II), R2 = SiMe2SiMe2 (III)], IV and V, all of which exhibit low 1st ionization potentials, were oxidized with AlCl3 in CH2Cl2 to form the 1st examples of delocalized, \textgreek{s}-electron radical cations, which were studied by ESR spectroscopy. Unlike the well-known radical anion of II, the radical cation gives an ESR spectrum which can be simulated only by assuming 2 sets of 18 equiv. protons, corresponding to 6 axial and 6 equatorial Me groups which do not become equiv. on the ESR time scale. The high g value of 2.0093 obsd. for the radical cation suggests a considerable spin population in the Si6 ring skeleton. The radical cations of III, IV and V show only overlapping signals in the ESR, but their resp. g values of 2.010, 2.0105 and 2.0063 are also consistent with spin delocalization into the \textgreek{s}Si-Si system. [on SciFinder(R)]},
added-at = {2019-07-15T13:41:23.000+0200},
author = {Bock, H. and Kaim, W. and Kira, M. and West, R.},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/20c728207ab0839636e69629dc167434a/b_schwederski},
doi = {10.1021/ja00520a006},
interhash = {b4b86a6c16e9ddf169e24f5a079a3d2e},
intrahash = {0c728207ab0839636e69629dc167434a},
issn = {0002-7863},
journal = {Journal of the American Chemical Society},
keywords = {ESR ESR;ionization ESR;photoelectron MO;oxidn cyclopentasilane cyclopoly cyclopolysilane deriv;silane permethyl permethylcyclopolysilane permethylcyclopolysilane;permethylcyclopolysilane potential radical spectrum},
number = 26,
pages = {7667--7670},
timestamp = {2019-07-15T11:42:10.000+0200},
title = {Novel organosilicon radical cations. One-electron oxidation of permethylcyclopolysilanes},
volume = 101,
year = 1979
}
