A new look at the structure and reactivity of 10-vertex nido-dicarbaboranes

The electronic structure of nido-B10H14 and [6-Ph-nido-6-CB9H11]− in terms of Bader’s theory (AIM)

“…The absence of bond critical points (CP b (3, À1)) was found under BH ex B bridges, which seems to be typical for nido structures [6,16,17]. Also there is no CP b (3, À1) in B7-B8 and B5-B10 pairs for both species 1 and 2 which is consistent with elongated interatomic distances discussed above.…”

“…The deviation of their open faces from planarity is the reason of polyhedra splitting into two {B 6 } subclusters in 1 and {B 6 } and {CB 5 } subclusters in 2 thus achieving more favorable orbital overlapping for B-B bond. It should be noted that unlike B-B bond the deviation from planarity does not affect the formation of C-B bond as it was shown for 10-vertex dicarborane nido-5,6-C 2 B 8 H 12 studied earlier [6]. …”

“…These sites become preferable for the attack of metal fragment which can result in cleavage of one or more vertex to generate a cage contraction. The removing of extrahydrogens as it was demonstrated in [6] is able to afford the charge concentration on the open face, thus the atoms comprising the open face become practically equal for metal fragment and formation of p-complexes can occur without cage degradation.…”

“…Similarly to the polyhedron of 10-vertex dicarborane [6] not all edges of cages 1 and 2 correspond to two-center bonds. The absence of bond critical points (CP b (3, À1)) was found under BH ex B bridges, which seems to be typical for nido structures [6,16,17].…”

“…As the electron structure governs the chemical properties of any molecule, it was of interest to portray the structure of 10-vertex nido clusters in terms of Bader's theory ''Atoms in Molecules'' (AIM) [5]. Earlier, one representative of 10-vertex nidocarborane clusters with two carbon atoms in the cage, namely nido-5,6-C 2 B 8 H 12 and its anion [nido-C 2 B 8 H 11 ] À were chosen for the study [6]. It was found that computed molecular graph differs notably from the traditional depiction of this cluster.…”