Cage-fluorination during deboronation of meta-carboranes

Geometries of 11‐Vertex Carborane Monoanion Radicals with 2n+3 Skeletal Electron Counts

“…As the 2 n +2 geometries 4 – 6 are structurally similar to the radical anions [ 4 – 6 ] · – , the alternative geometries of the radicals [ 4A – 6A ] · – are unlikely to exist in solutions kinetically as well as thermodynamically on reduction. However, the alternative 2 n +4 dianion geometries [ 4A – 6A ] 2– are more stable than the dianion geometries [ 4 – 6 ] 2– described earlier, so these results support the observed vertex flip process taking place via the dianion intermediate in some deboronation–substitution reactions of 12‐vertex closo ‐carboranes with alkoxides and fluorides . The BH flipping energy barriers in these 2 n +4 dianions are substantial at 23.0 to 24.7 kcal mol –1 , thus severe reaction conditions (e.g.…”

“…Some studies report the unusual formation of substituted 11-vertex nido-monoanions from deboronation-substitution of 12-vertex closo-carboranes with alkoxides [30,31] and fluorides. [31,32] Flipping of the BH vertex has been proposed to explain these and other 11-vertex nido-cluster rearrangements. [33] The fluoride ion deboronations of 1,7-(diaryl) 2 -meta-carboranes are examples of the vertex-flipping process as shown in Figure 7.…”

“…Largest Averaged Largest [4A-6A] 2are more stable than the dianion geometries [4-6] 2described earlier, so these results support the observed vertex flip process taking place via the dianion intermediate in some deboronation-substitution reactions of 12-vertex closocarboranes with alkoxides and fluorides. [30][31][32] The BH flipping energy barriers in these 2n+4 dianions are substantial at 23.0 to 24.7 kcal mol -1 , thus severe reaction conditions (e.g. reflux) would be required for the BH flip processes to occur in the dianions of 4-6.…”

Synthesis and crystal structure of an assembly of three ortho‐carborane cages linked via para‐phenylene units: effect of aryl orientation on cage CC bond lengths in C‐aryl‐ortho‐carboranes

“…Peak assignments of cage boron, hydrogen and carbon atoms were determined with the aid of selective 1 H{ 11 B}, correlated 1 H-13 C spectra and comparison with literature values of related aryl carboranes. 59,60 Mass spectra were recorded on a VG Micromass 7070E instrument under electron impact conditions at 70 eV.…”

Ruthenium carboranyl complexes with 2,2′-bipyridine derivatives for potential bimodal therapy application

“…3 These species have two moderately acidic C-H vertices that are easily deprotonated with strong bases and functionalized using electrophiles. 4 On the other hand, the anionic nido-carborane ([C 2 B 9 H 12 ] À and [C 2 B 9 H 11 ] 2À ) derivatives result from the known as "partial deboronation process", which takes place by the attack of a nucleophile [5][6][7][8][9][10][11][12][13] to the corresponding closo-C 2 B 10 H 12 cluster resulting in the loss of a B vertex. Metallacarboranes, neutral half-sandwich [M(C 2 B 9 H 11 ) LL 0 L 00 ] (L, L 0 , L 00 being anionic and/or neutral ligands) and the anionic sandwich metallabisdicarbollides [M(C 2 B 9 H 11 ) 2 ] À , are derivatives of boron hydrides that contain carbon and metal atoms into the fragment.…”