Cerium oxide nanoclusters: commensurate with concepts of polyoxometalate chemistry?

Abstract

The mixed-valent cerium(III/IV) oxide clusters {Ce(10)} and {Ce(22)}, derived from condensation reactions of cerium carboxylate coordination polymers, exhibit molecular growth tendencies similar to those of 'classical' group V and VI polyoxometalates, but with increasing nuclearity approach the structure of the parental oxide, CeO(2).

Influence of the pH on the Condensation of Tetravalent Cerium Cations in Association with [α‐SiW9O34]10– Leading to the Formation of a Ce6O4(OH)4 Core

“…Some rare examples of POMs stabilizing trimeric or hexameric condensed zirconium or hafnium cations were also synthesized by other research groups , . From a synthetic point of view, these polynuclear tetravalent compounds are relatively difficult to isolate as they tend to form oligomers that precipitate in solution and are usually obtained by combination of organic and inorganic chelating agents . A recent exploration of this behavior for hafnium cations was also proposed by Nyman and co‐workers …”

Magnetic Properties of 3D Heptanuclear Lanthanide Frameworks Supported by Mixed Ligands

“…4 As a result, a lot of pure lanthanide clusters, such as Ln 3 −Ln 10 , 5 Ln 12 −Ln 15 , 6 Ln 20 , 7 Ln 22 , 8 Ln 24 , 9 Ln 36 , 10 Ln 38 11 Ln 48 , 11,12 Ln 60 , 13 and Ln 104 , 14 have been documented. Recently, Yaghi et al proposed that metal cluster units may self-assemble into coordination polymers, 15 which will bring about the particular characteristics of the clusters into the obtained frameworks.…”

“…Herein, we report two new 3D frameworks [Ln 7 (DPA) 5 (NA) 3 (μ 3 -OH) 8 Pale-yellow crystals 1 and 2 can be obtained from the hydrothermal reaction of Ln 2 O 3 , HNA, and H 2 DPA. Singlecrystal X-ray diffraction analyses reveal 1 and 2 are isostructural and crystallize in the triclinic space group P1̅ .…”

“…Thus, only the structure of 1 will be discussed in detail. The asymmetrical unit of 1 consists of a neutral heptanuclear [Ln 7 (DPA) 5 (NA) 3 (μ 3 -OH) 8 (H 2 O) 3 ] cluster and 2.5 lattice water molecules. The heptanuclear [Gd 7 (μ 3 -OH) 8 ] 13+ core can be regarded as two vertex-sharing tetrahedra fused to each other through the Gd4 ion ( Figure 1), which is similar to the reported Ln 7 cores.…”

“…The asymmetrical unit of 1 consists of a neutral heptanuclear [Ln 7 (DPA) 5 (NA) 3 (μ 3 -OH) 8 (H 2 O) 3 ] cluster and 2.5 lattice water molecules. The heptanuclear [Gd 7 (μ 3 -OH) 8 ] 13+ core can be regarded as two vertex-sharing tetrahedra fused to each other through the Gd4 ion ( Figure 1), which is similar to the reported Ln 7 cores. 16c Gd1−Gd4 compose one tetrahedron with Gd···Gd separations in the range of 3.712−3.774 Å, and Gd4−Gd7 make up the other tetrahedron with Gd···Gd separations in the range of 3.663−3.848 Å.…”