J. Olliges et al., BORON NUCLEAR-QUADRUPOLE COUPLINGS AND LOCALIZED ELECTRONIC WAVE-FUNCTIONS IN THE BORON CLUSTERS O-CARBORANE AND O-SILABORANE, The Journal of chemical physics, 103(22), 1995, pp. 9568-9573
The B-11 nuclear quadrupole couplings in ''o-silaborane'' [1,2-dimethy
l-1,2- disila-closo- dodecaborane(12), B10Si2(CH3)(2)H-10] were measur
ed at 77 K with a nuclear quadrupole double resonance spectrometer wit
h rapidly switched magnet. Three B-11 transitions were found which wer
e assigned by comparison with ab initio calculations of the electric f
ield gradients. The surprising difference in the order of the quadrupo
le couplings of equivalent borons in o-silaborane and the correspondin
g carbon compound o-carborane (B10C2H12) is explained by the different
valence bond structures of the two boron clusters which were obtained
by localization of the electronic wave functions. (C) 1995 American I
nstitute of Physics.