Two tetranuclear Tb(III)-based clusters: Crystal structures and effectively catalyze the cycloaddition of CO2 with epoxides

Two new and interesting tetranuclear Tb(III)-based clusters [Tb4(NO3)2(acac)4(HL)2(CH3OH)2]·2(CH3CN)] (1) and [Tb4(NO3)2(acac)4(L)2(CH3CH2OH)2] (2) (H4L1 = 2-(hydroxymethyl)-2-(((2-hydroxynaphthalen-1-yl)methylene)amino)propane-1,3-diol); H3L2 = 2-(((2-hydroxynaphthalen-1-yl)methylene)amino)-2-methylpropane-1,3-diol; and Hacac = acetylacetone) have been successfully synthesized by using two polydentate Schiff base ligands (H3L2 and H4L1). The crystal structures, fluorescent properties, magnetic properties and catalytic properties of the two clusters 1 and 2 have been systematically studied. Interestingly, both clusters 1 and 2 can catalyze the cycloaddition of CO2 with epoxides with high efficiency under mild conditions; and cluster 1 as a catalyst could be reused at least three times without obvious loss of catalytic performance.