Microwave spectrum, structure, and dipole moment of 1,6-dicarbanonaborane(9)

Molecular structure of 1-thia-closo-dodecaborane(II) studied by electron diffraction complemented by ab initio calculations

“…There is an excellent agreement of the first two parameters with the corresponding GED ones. The IGLO values (DZ// 6-31G*, in ppm) are (BM) -0.7, (B7_n) -10.0, and (B12) 23.1 ppm, quite similar to the DZ//GED and DZ//3-21G(*) results.…”

“…1.98 and 1.99 Á for 1,6-C2B7H9. 23 The axial sulfur placement leads to a substantial lengthening of the B-B linkages in the pentagonal belt adjacent to sulfur. This also is obvious in the theoretical structures (see Table IV).…”

Azacarbaborane chemistry. Butyl nitrite synthesis of the new eight-, nine- and ten-vertex azacarbaboranes exo- and endo-7-CH3-hypho-7,8-NCB6H11, nido-6,8,9-NC2B7H10, arachno-6,5,9-NC2B7H12 and arachno-6,5,10-C2NB7H12

“…Nevertheless, values of similar magnitude, 1.976 and 1.995 Å, were established, e.g., in the microwave study of closo-1,6-C 2 B 7 H 9 . 23 The GIAO-HF results for all molecules suggest that the corresponding MP2/6-31G* geometries can be deemed reasonably good representations of the geometries of relatively free molecules in solution. Comparison between theoretical and experimental 11 B chemical shifts in Table 1 generally reveals reasonable agreement, at least the calculated values follow the general trends in experimental shifts.…”

Interaction of Trimethylamine and closo-1,6-C2B7H9. Evidence for an “Open” Cage C2B7H9/Amine Adduct

“… a 13 C NMR shifts are relative to tetramethylsilane; 11 B NMR shifts are relative to Et 2 O·BF 3 ; negative values are to high field. To within 0.4 ppm, the δ(rt) chemical shift values of C 2 B 7 H 9 in trimethylamine are the same as those in either CCl 4 , hexane, Freon-12 (CCl 2 F 2 ), or in Freon-22 (HCClF 2 ). , …”

“…No information is available, to our knowledge, on the interaction of the closo -carborane 1,6-C 2 B 7 H 9 with trimethylamine. Another Lewis base, the F - ion, is known to react with 1,6-C 2 B 7 H 9 to yield a carborane anion that is the result of partial cage degradation of the starting material .…”