The largest Se-4f cluster incorporated polyoxometalate with high Lewis acid–base catalytic activity

A 4p-4f cluster incorporated polyoxometalate (POM), namely, H18{[(H4pic)4Eu10Se13O28(H2O)12](α-GeW9O34)4·40H2O (1-Eu, H4pic = isonicotinic acid), has been first synthesized and characterized. 1-Eu features an interesting four-shell structure, representing the largest Se-4f cluster incorporated POM known to date. Besides, 1-Eu exhibits excellent Lewis acid-base catalytic activity and reusablity in catalyzing the gram-scale dehydration condensation reaction of hydrazines and 1,3-diketones to synthesize polysubstituted pyrazoles.