Synthesis and structural characterization of a series of tetranuclear lanthanide clusters

Tetranuclear lanthanide clusters of composition [Ln(4)(mu(3)-OH)(2)(Ph(2)acac)(10)] (Ln = Pr, Nd, and Sm) (Ph(2)acac = dibenzoylmethanide) were prepared starting from [LnCl(3)(.)(n H2O)] (n = 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 mu(3)-oxygen atoms, and ten Ph(2)acac ligands, which make up the peripheral part of the cluster. Three types of coordination modes (n(2_), (mu O-_)(_)n(,)(2_) and mu-O)(2)-n(2)) are observed for the Ph(2)acac ligation to the metal centers.