Synthesis and Structural Characterization of a Series of Tetranuclear Lanthanide Clusters

Abstract

Tetranuclear lanthanide clusters of composition [Ln 4 (µ 3 -OH) 2 (Ph 2 acac) 10 ] (Ln ϭ Pr, Nd, and Sm) (Ph 2 acac ϭ dibenzoylmethanide) were prepared starting from [LnCl 3 ·(n H 2 O)] (n ϭ 6, 7) with 2.5 equivalents dibenzoylmethane in presence of triethylamine. Single crystals X-ray analyses of compounds 1 -3 revealed that each cluster consists of four lanthanide atoms, two µ 3 -oxygen atoms, and ten Ph 2 acac ligands, which make up the peripheral part , 2782Ϫ2785 of the cluster. Three types of coordination modes (η 2 -, (µ-O)-η 2 -, and µ-O) 2 -η 2 ) are observed for the Ph 2 acac ligation to the metal centers.

Synthesis and Structural Characterization of Tetra‐ and Pentanuclear Lanthanide Hydroxido Clusters

“…Two types of coordination modes are observed for the ligation of Ph 2 acac to the metal centers in the clusters. Of the eight Ph 2 acac ligands, six chelate the metal centers in η 2 fashion, and two more both chelate and bridge two metal centers, thus they are (µ-O) 2 10 ] (Ln = Pr, Nd, and Sm) [15] shows the same interesting features as those observed for compounds 1 and 2. The tetranuclear Ln core in [Ln 4 (µ 3 -OH) 2 A significant difference arises with respect to the ionic radius of the center metal.…”

“…[13] In contrast, by using the larger lanthanides, tetranuclear clusters of composition [Ln 4 (µ 3 -OH) 2 (Ph 2 acac) 10 ] (Ln = Pr, Nd, and Sm) were obtained in a similar manner. [15] Single-crystal X-ray analysis of these compounds revealed that each cluster consists of four lanthanide atoms, two µ 3 -oxygen atoms, and ten Ph 2 acac ligands, which make up the peripheral part of the cluster. Three types of coordination modes [η 2 -, (µ-O)-η 2 -, and (µ-O) 2 -η 2 ] are observed for the ligation of Ph 2 acac to the metal centers.…”

“…A comparable Ln 4 core was observed earlier in [Nd 4 (µ 3 -OH) 2 (µ 2 -,µ 1 -acac) 6 -(acac) 4 ] (acac = acetylacetonate) [28] and [Ln 4 (µ 3 -OH) 2 -(Ph 2 acac) 10 ] (Ln = Pr, Nd, and Sm). [15] Compounds 3 and 4 are pseudopolymorphic to each other, because the amount of noncoordinated solvent (toluene) in the unit cell differs for each compound. Two types of coordination modes are observed for the ligation of Ph 2 acac to the metal centers in the clusters.…”

Luminescent Polymeric Dispersions and Films Based on Oligonuclear Lanthanide Clusters

“…The latter pathway for example involves the reaction of [LnCl 3 Á(n H 2 O)] (n ¼ 6, 7) with a suitable ligand in the presence of a base to give nanoscaled cluster compounds. [10,[15][16][17][18] In general, the cage dimensions depend on the sizes of both the lanthanide(III) ion (Ln 3þ ) and the ligand. In this context, we and others have reported the synthesis and structure of pyramidally shaped pentanuclear lanthanide clusters, [Ln 5 (OH) 5 The successful embedding of different amounts and types of hydrophobic rare earth clusters (Ln ¼ Y, Pr, Eu, Sm, Nd) in various polymer matrices via miniemulsion polymerization is presented.…”

“…[16,22] Single crystal X-ray analysis of these compounds revealed that each cluster consists of four lanthanide atoms, two m 3 -oxygen atoms, and ten Ph 2 acac ligands which make up the peripheral part of the cluster. Three coordination modes (h 2 -, (m-O)-h 2 -, and (m-O) 2 -h 2 ) are observed for the Ph 2 acac ligation to the metal centers.…”