Hexanuclear 3d–4f complexes as efficient catalysts for converting CO2 into cyclic carbonates

A series of novel hexanuclear 3d-4f complexes formulated as {[Ln2Zn4(μ3-OH)2L4(AcO)2(NO3)2(DMF)2]·2(CH3OH), LnIII = Dy3+ (1), Nd3+ (2), Tb3+ (3)} have been synthesized and characterized. These complexes 1-3 show excellent catalytic performance for the cycloaddition of CO2 and epoxides to obtain cyclic carbonates. The catalytic system has a wide substrate scope with high turnover numbers (9700) and high turnover frequencies (808 h-1) under mild conditions. Additionally, the catalysts could be conveniently prepared on a large scale and recycled.