Isolation of a chloride-capped cerium polyoxo nanocluster built from 52 metal ions

Four cerium compounds - (HPy) 2 [CeCl 6 ]·2(HPyCl) ( Ce1-1 ), (HPy) 2 [CeCl 6 ] ( Ce1-2 ), (HPy) m [Ce 38 O 56− x (OH) x Cl 50 (H 2 O) 12 ]· n H 2 O ( Ce38 ), and (HPy) m [Ce 52 O 80− x (OH) x Cl 59 (H 2 O) 17 ]· n H 2 O ( Ce52 ) - were crystallized from acidic aqueous solutions using pyridinium (HPy) counterions. The latter consists of two unique cerium oxide nanoclusters that are built from 52 metal ions and represents the largest chloride capped {Ce III/IV O} and/or {M IV O} (M = Ce, Th, U, Np, Pu) nanocluster that adopts the fluorite-type structure of MO 2 that has been reported. A chloride/water terminated Ce-oxo cluster built from 52 metal ions, with the longest Ce-Ce distance measuring roughly 1.6 nm, was isolated from acidic aqueous solution using pyridinium counterions.