Palladium(II)-rare-earth metal(III) paddlewheel carboxylate complexes: Easy total acetate to pivalate metathesis

Bis-paddlewheel heterobimetallic complexes in which palladium(II) is connected to the rare-earth metals(III) [Pd(mu-OOCMe)(4)Ln(OH2)(mu,eta(2)-OOCMe)](2) x 2HOOCMe (Ln = Nd, Sm, Eu, Yb and Tm) by four acetate bridges were synthesised by the reaction of Pd-3(mu-OOCMe)6 with the Ln(III) acetates. The tetraacetate-bridged complexes were unexpectedly found to be readily transformed by the stoichiometric amount of pivalic acid into the mono-paddlewheel tetrapivalate-bridged analogues in which the paddlewheel structure [Pd(mu-OOCR)(4)Ln] maintains as established by X-ray crystallography. The role of the intra-and intermolecular H-bonding in these complexes is discussed. (C) 2008 Elsevier Ltd. All rights reserved.