Alkylidyne(carbaborane) complex of the group 6 metals. 3. Facile transformations of 12- and 13-vertex tungstacarborane polyhedra reversible. Framework rearrangement and acid-induced ejection of a cage vertex

Selenium and tellurium derivatives of a monocarbon platinacarbaborane complex †

“…Moreover, B(2), the atom of the carbaborane group to which the SePh group is attached, is located in an α site with respect to the carbon in the CBBBB ring ligating the platinum. The Se(2)᎐B(2) distance [1.984(9) Å] in 2a is somewhat shorter than those [2.016 (15) and 2.023 (16) Å] in the salt [NEt 4 ] 2 [Se 3 B 11 H 9 ], a disubstituted derivative of [closo-B 11 H 11 ] 2Ϫ in which an Se 3 chain bridges two boron atoms. 2 The Pt᎐Se(1) separation [2.4438(8) Å] lies within the range [2.376(2)-2.590 (7) Å] observed in various complexes containing Pt᎐Se bonds.…”

Alkyne‐Promoted H2Loss in a Metallaborane:Nido‐to‐ClosoCluster Transformation and sp CH Bond Oxidative Addition

“…Although several 12‐vertex metallacarboranes containing Mη 2 ‐alkyne linkages have been reported,4–6 to our knowledge, no rhodaheteroboranes (including rhodacarboranes) have to date been crystallographically characterised that exhibit Rhη 2 ‐alkyne bonds. Compound 3 crystallises in the triclinic system with two molecules in the unit cell.…”

Transition Metal Metallacarbaboranes

“…317 In a departure f r o m 12-vertex chemistry, protonation o f the 13-vertex alkylidyne metallacarbaboranes often leads to facile loss of the protonated boron vertex, generating an icosahedral MC 2 B 9 cluster. 244 (Figure 24). 319 The propensity of some 13-vertex metallacarbaboranes to undergo low-energy rearrangement involving separation of the cage carbon atoms, 244 ' 321 in some cases reversibly, 244 is a notable feature of these systems, reminiscent of previously observed reversible isomerizations in small metallacarbaboranes.…”

“…244 (Figure 24). 319 The propensity of some 13-vertex metallacarbaboranes to undergo low-energy rearrangement involving separation of the cage carbon atoms, 244 ' 321 in some cases reversibly, 244 is a notable feature of these systems, reminiscent of previously observed reversible isomerizations in small metallacarbaboranes. 98d A rare example of an open 13-vertex cage is afforded by the gold complex 322 mVfo-(Ph3P)Au(7,9-Me 2 C 2 B 1 0 H 1 0 )~ in which the metal is coordinated to just three borons on the six-membered open face of the carbaborane ligand.…”

“…Rearrangements entailing separation of the cage carbon atoms can occur at relatively low energy, as shown in the conversions of 3,1,2-to 3,1,1 l-PtC 2 B 9 icosahedra at 25-55 °C and of several alkylidyne-tungstacarboranes at temperatures as low as -78 OQ 244 ' 245 ' 273 in one case, reversibility was observed. 244 (Reversible cage isomerizations have been long known in 6-to 9-vertex cobaltacarbaboranes. 98d ) The bis(phosphino)hydridoiridacarbaboranes 3,l,2-(Ph 3 P) 2 HIr(RC 2 B 9 H 10 ) (R = H, Ph) were readily converted to the corresponding 2,1,8-isomers on reflux in benzene.…”