Lanthanide clusters as highly efficient catalysts regarding carbon dioxide activation†
A series of tetranuclear lanthanide clusters supported by organic ligands ([Ln4L6(NO3)4]·4(MeCN), Ln = La, Nd, Sm) has been synthesized and characterized. The Lewis acidic Ln3+ sites were investigated as highly efficient catalysts regarding CO2 activation. The clusters showed significant thermal stability after 4 reaction cycles of CO2 insertion into epoxides to form cyclic carbonates, with TOF up to 6700 h−1. The catalytic system also displays a wide substrate scope and high catalytic activity. Unfortunately, the catalytic efficiency of the catalysts for some sterically hindered reaction substrates is not very satisfactory.