Unique properties of C,C′-linked nido-biscarborane tetraanions. Synthesis, structure and bonding of ruthenium monocarbollide via unprecedented cage carbon extrusion

Abstract

Four reaction pathways have been found in the reaction of a C,C′-linked nido-biscarborane tetraanionic salt with [Ru(p-cymene)Cl₂]₂, leading to the isolation and structural characterization of redox, triple cage B–H oxidative addition, cage expansion and cage carbon extrusion products. Among these, the unprecedented cage carbon extrusion results in the formation of a new 6π-electron carboranyl ligand [C₂B₁₀H₁₀]²⁻. The bonding interactions between this ligand and the Ru(II) center have also been discussed on the basis of DFT calculations.