We next evaluated the reactivity of 2 towards CO2 (Scheme 4). The addition of CO2 (1.3 bar, excess) to a solution of 2 in toluene led to an immediate reaction at room temperature. After work-up, red crystals of 9 suitable for XRD studies were obtained in good yield (71%) from a concentrated pentane solution. The molecular structure of the complex is depicted in Figure and reveals the formation of an unexpected product in which C-H activation at the para position of the toluene solvent occurred, yielding an unprecedented polyoxygenated ligand framework. In the resulting tetranuclear Tm(III) complex, only six Cp ttt ligands are present, suggesting that two Cp ttt ligands have been released in their protonated form.