Synthesis and structural characterization of tetra- and pentanuclear lanthanide hydroxido clusters

Tetra- and pentanuclear lanthanide clusters having dibenzoylmethanido and o-nitrophenolato as ligands in the coordination sphere were prepared. Treating [LnCl(3.6)H(2)O] (Ln = Er, Tm) with dibenzoylmethane and o-nitrophenol in the presence of triethylamine yielded the pentanuclear lanthanide clusters HNEt3+[Ln(5)(mu 3-OH)(4)(mu(4)-OH)(Ph(2)acac)(7)(0-O2NC6H4O)(3)Cl](-) (Ln = Er, Tm). Under the same reaction conditions but using Yb and Lu as center metals, tetranuclear lanthanide clusters [Ln(4)(mu(3)-OH)(2)(Ph(2)acac)(8)(o-O2NC6H4O)(2)] (Ln = Yb, Lu) were obtained. The structures of all new compounds were confirmed by single-crystal X-ray diffraction. The anions of the pentanuclear lanthanide cores are square pyramidal. Each triangular face of the square pyramid is capped by one mu(3)-O moiety. In the square base, four lanthanide atoms are linked by one mu(4)-O atom. The formation of the hydroxido bridges can be explained by deprotonation of the coordinated water molecules. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)