Partially cyclopentadienyl-substituted tetranuclear lanthanide Schiff base complexes

Treatment of Cp3Ln (Ln=Pr, Nd) with an equimolar amount of the Schiff base bis(acetylacetone)ethylenediamine (H2acacen) half hydrate (H2L1·1/2H2O) or bis(salicylidene)trimethylenediamine (H2saltn) half hydrate (H2L2·1/2H2O) in THF affords three novel μ-hydroxo-bridged tetranuclear organolanthanide complexes [η5-CpLn2L2(μ-OH)]2·nTHF, L=L1, n=4, Ln=Pr (1), Nd (2); L=L2, n=2, Ln=Nd (3). A reaction scheme was proposed in which the cyclopentadienyl lanthanide coordination motif [CpLnL] (A) and the hydroxyl lanthanide motif [LnL(OH)] (B) cross-reacted and then dimerized through the μ-hydroxo bridges to give the tetranuclear Ln complexes containing an Ln4O8 skeleton with two reciprocally oriented face-sharing defect cubanes. In each monomeric species [CpLn2L2(OH)] (C) the Ln atoms are 8- or 9-coordinated. All complexes have been characterized by EA, IR and Mass spectroscopy.