Articles you may be interested inBoron quadrupole coupling in o r t h ocarborane. NMR study of an oriented liquid sample J. Chem. Phys. 85, 3217 (1986); 10.1063/1.450990 Local space approximation for configuration interaction and coupled cluster wave functions J. Chem. Phys. 85, 2791 (1986); 10.1063/1.451036 Boron nuclear quadrupole coupling in o and mcarborane (B1 0C2H1 2) J. Chem. Phys. 85, 3136 (1986); 10.1063/1.450980 Molecular reorientation and boron nuclear quadrupole interaction in crystalline o r t h ocarboraneThe 11 B nuclear quadrupole couplings in ''o-silaborane'' ͓1,2-dimethyl-1,2disila-closo-dodeca-borane͑12͒, B 10 Si 2 ͑CH 3 ) 2 H 10 ] were measured at 77 K with a nuclear quadrupole double resonance spectrometer with rapidly switched magnet. Three 11 B transitions were found which were assigned by comparison with ab initio calculations of the electric field gradients. The surprising difference in the order of the quadrupole couplings of equivalent borons in o-silaborane and the corresponding carbon compound o-carborane ͑B 10 C 2 H 12 ) is explained by the different valence bond structures of the two boron clusters which were obtained by localization of the electronic wave functions.

No abstract

No abstract

The n B and l9F nuclear quadrupole couplings in F 3BNH V(CH3)3_;(. compounds are reported. The boron quadrupole couplings were measured by quadrupole perturbed N M R in the solid state. The fluorine quadrupole couplings were obtained by the time-differential observation of the angular distribution of the gamma radiation after excitation o f the fluorine nuclei with accelerated protons (TDPAD). The results are discussed in connection with the nitrogen quadru pole couplings in F 3BNHV R 3_* compounds, and the nitrogen and boron quadrupole couplings in H 3BNHvR 3_x: compounds which were previously determined by nuclear quadrupole double resonance. In the F 3BNHyR 3_x series of compounds, the donor-acceptor character o f the B -N bond appears to be less im portant than in the H 3BNH V R 3_^ compounds in favour of a more ionic character of the bond with a higher negative charge on nitrogen.

No abstract