An unexpected cluster opening upon the formation of electronically unsaturated η3-(cyclooctenyl)metallacarboranes of rhodium(III) and iridium(III) with sterically reduced [(PhCH2)2C2B9H9]2− ligand

Novel 16-electron pseudocloso rhoda- and iridacarboranes with C,C′-dibenzylsubstituted {C2B9}-carborane ligand were synthesized and characterized by a combination of NMR and single-crystal X-ray diffraction data as well as Bader's topological analysis based on solid-state DFT calculations. Possible mechanism of stabilization of 16-electron metal (III) centers in these complexes via donating to metals of electron density released from the polyhedral C-C bond cleavage is discussed.