Monoanionic hexaborate cluster radicals B6HalnHal'6-n.bul.- with mixed halogen substitution were prepd. from oxidizable dianionic precursors and were characterized by vibrational and UV-visible spectroscopy. EPR studies of these and the structurally established homoleptic species B6Hal6.bul.- (Hal = Cl, Br, I) reveal strongly increasing g anisotropy and relaxation rate on replacing Cl by Br and esp. I substituents; the very stable B6I6.bul.- ion (g1 = 2.04, g2 = 1.66, g3 = 1.15) thus exhibits an EPR spectrum only at 4 K. The extent of these effects is attributed to the Jahn-Teller situation in B6X6.bul.- with only partial occupancy of a degenerate MO. Both the absence of B-H bonds and the evidently strong participation of the halogen substituents in the singly occupied MO contribute to the extraordinary stability of these cluster radicals. on SciFinder(R)
%0 Journal Article
%1 Lorenzen.1998
%A Lorenzen, Volker
%A Preetz, Wilhelm
%A Baumann, Frank
%A Kaim, Wolfgang.
%D 1998
%J Inorganic Chemistry
%K ESR;radical cluster cluster;Raman cluster;magnetic cluster;perhalogenated dianionic electrochem hexaborate monoanionic oxidn perhalogenated prepn property stabilization
%N 16
%P 4011--4014
%R 10.1021/IC9802698
%T Paramagnetic Cluster Ions B6HalnHal'6-n.bul.- (Hal, Hal' = Cl, Br, I). EPR Evidence for Radical Stabilization through Electronic Effects of the Halogen Substituents
%V 37
%X Monoanionic hexaborate cluster radicals B6HalnHal'6-n.bul.- with mixed halogen substitution were prepd. from oxidizable dianionic precursors and were characterized by vibrational and UV-visible spectroscopy. EPR studies of these and the structurally established homoleptic species B6Hal6.bul.- (Hal = Cl, Br, I) reveal strongly increasing g anisotropy and relaxation rate on replacing Cl by Br and esp. I substituents; the very stable B6I6.bul.- ion (g1 = 2.04, g2 = 1.66, g3 = 1.15) thus exhibits an EPR spectrum only at 4 K. The extent of these effects is attributed to the Jahn-Teller situation in B6X6.bul.- with only partial occupancy of a degenerate MO. Both the absence of B-H bonds and the evidently strong participation of the halogen substituents in the singly occupied MO contribute to the extraordinary stability of these cluster radicals. on SciFinder(R)
@article{Lorenzen.1998,
abstract = {Monoanionic hexaborate cluster radicals [B6HalnHal'6-n].bul.- with mixed halogen substitution were prepd. from oxidizable dianionic precursors and were characterized by vibrational and UV-visible spectroscopy. EPR studies of these and the structurally established homoleptic species [B6Hal6].bul.- (Hal = Cl, Br, I) reveal strongly increasing g anisotropy and relaxation rate on replacing Cl by Br and esp. I substituents; the very stable B6I6.bul.- ion (g1 = 2.04, g2 = 1.66, g3 = 1.15) thus exhibits an EPR spectrum only at 4 K. The extent of these effects is attributed to the Jahn-Teller situation in [B6X6].bul.- with only partial occupancy of a degenerate MO. Both the absence of B-H bonds and the evidently strong participation of the halogen substituents in the singly occupied MO contribute to the extraordinary stability of these cluster radicals. [on SciFinder(R)]},
added-at = {2019-07-15T13:41:23.000+0200},
author = {Lorenzen, Volker and Preetz, Wilhelm and Baumann, Frank and Kaim, Wolfgang.},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/22f1f08e3a9b5c7fe5ef2f269d92fb22c/b_schwederski},
doi = {10.1021/IC9802698},
interhash = {16bd4f3fd8a973bb3cb496b9846146c1},
intrahash = {2f1f08e3a9b5c7fe5ef2f269d92fb22c},
issn = {0020-1669},
journal = {Inorganic Chemistry},
keywords = {ESR;radical cluster cluster;Raman cluster;magnetic cluster;perhalogenated dianionic electrochem hexaborate monoanionic oxidn perhalogenated prepn property stabilization},
number = 16,
pages = {4011--4014},
timestamp = {2019-07-15T11:42:10.000+0200},
title = {Paramagnetic Cluster Ions [B6HalnHal'6-n].bul.- (Hal, Hal' = Cl, Br, I). EPR Evidence for Radical Stabilization through Electronic Effects of the Halogen Substituents},
volume = 37,
year = 1998
}
