Synthesis of polyhedral phosphaboranes: crystal structure of 6-(C2H5)3N.cntdot.2-PB9H8

Indirect nuclear spin-spin coupling in tetrachlorotetraborane(4) and halogenated polyhedral phospha- and arsaboranes

“…2 An unsuccessful experiment has been reported for 1,2-P 2 B 10 H 10 ; however, the set-up of the experiment was not described. 13 Here we show that 1D homonuclear 11 Bf 11 Bg decoupling is a powerful tool, especially for high-field, NMR spectrometers. In the case of 5, a sharp singlet remains either at low or high field, depending on the decoupled 11 (Fig.…”

“…Simulations of experimental 11 B NMR spectra have been reported for 1,2-P 2 B 10 H 10 . 13 However, the complexity of the spin system was not mentioned and it is not clear how the result was achieved, since the program used does not take into account partially relaxed scalar coupling between quadrupolar nuclei. If one neglects long-range 11 B-11 B coupling, 11 B(4,6,8,11) decoupling should give rise to an A 2 X 2 spin system involving the 11 B(2,3) and the 31 P(1,7) nuclei, which is reflected by the triplet for the 11 B(2,3) resonance with 1 J 31 P, 11 B D 38.5 Hz at high field (Fig.…”

The presence of cobaltdibismuth triangular faces in the lowest energy deltahedral cobaltadibismaborane polyhedra: Major differences from their cobaltadiphosphaborane analogues

“…In all of the lowest energy CpCoP 2 B nÀ3 H ne3 structures the central CoP 2 B ne3 polyhedra are found to be the most spherical deltahedra similar to those found in the corresponding B n H 2À n dianions ( Fig. 1 for n ¼ 10, 11,12). The lowest energy CpCoP 2 B nÀ3 H ne3 structures typically but not always have the cobalt atom at a degree 5 or 6 vertex and the phosphorus atoms at degree 4 vertices.…”

“…Major differences between the preferred structures of the cobaltadiphosphaboranes CpCoP 2 B ne3 H ne3 and those of the corresponding cobaltadibismaboranes CpCoBi 2 B nÀ3 H ne3 (n ¼ 10, 11,12) are predicted from this theoretical study. In particular, the lowest energy CpCoP 2 B ne3 H ne3 structures were previously found to have the phosphorus atoms as far apart as possible [14].…”

“…In this connection replacement of two CH groups by bare phosphorus atoms in the dicarbaboranes C 2 B nÀ2 H n gives the corresponding diphosphaboranes P 2 B ne2 H ne2 . The icosahedral diphosphaborane P 2 B 10 H 10 was first synthesized in relatively low yield by Todd and co-workers in 1989 [11] and much later in better yield by Welch and co-workers [12]. An isomer of the cobalt complex CpCoP 2 B 9 H 9 has been synthesized from P 2 B 10 H 10 and structurally characterized by X-ray crystallography [13].…”