Cerium(IV) Hexanuclear Clusters from Cerium(III) Precursors: Molecular Models for Oxidative Growth of Ceria Nanoparticles

摘要: Reactions of cerium(III) nitrate, Ce(NO3 )3 ⋅6 H2 O, with different carboxylic acids, such as pivalic acid, benzoic and 4-methoxybenzoic in the presence a tridentate N,N,N-donor ligand, diethylenetriamine (L(1) ), under aerobic conditions yielded corresponding cerium hexamers Ce6 O8 (O2 CtBu)8 )4 (1), CC6 H5 )8 (2), H4 -4-OCH3 (3). Hexamers 1, 2, 3 contain same octahedral Ce(IV) 6 core, which all interstitial oxygen atoms are connected by μ3 -oxo bridging ligands. In contrast, treatment precursor (NH4 )2 )6 (CAN) acid ligand L(1) afforded O4 (OH)4 CtBu)12 (4), exhibiting deformed core containing -hydroxo moieties defined positions. contrast to formation 1-3, use N-methyldiethanolamine (L) reaction O previously reported Ce(III) dinuclear cluster, Ce2 CtBu)6 L2 , even dioxygen. ESI-MS analysis mixture clearly indicated importance promoting oxidation aggregates, [Cen CtBu)3n ], is necessary for hexamers.