Nanoscale Organolanthanum Clusters: Nuclearity-Directing Role of Cyclopentadienyl and Halogenido Ligands |
| |
| Authors: | Dennis A Buschmann Dr H Martin Dietrich Dr David Schneider Dr Verena M Birkelbach Dr Christoph Stuhl Prof Dr Karl W Törnroos Dr Cäcilia Maichle-Mössmer Prof Dr Reiner Anwander |
| |
| Institution: | 1. Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany;2. Department of Chemistry, University of Bergen, Allégaten 41, 5007 Bergen, Norway |
| |
| Abstract: | Tetramethylaluminato/halogenido(X) ligand exchange reactions in half-sandwich complexes CpRLa(AlMe4)2] are feasible in non-coordinating solvents and provide access to large coordination clusters of the type CpRLaX2]x. Incomplete exchange reactions generate the hexalanthanum clusters CpR6La6X8(AlMe4)4] (CpR=Cp*=C5Me5, X=I; CpR=Cp′=C5H4SiMe3, X=Br, I). Treatment of Cp*La(AlMe4)2] with two equivalents Me3SiI gave the nonalanthanum cluster Cp*LaI2]9, while the exhaustive reaction of Cp′La(AlMe4)2] with the halogenido transfer reagents Me3GeX and Me3SiX (X=I, Br, Cl) produced a series of monocyclopentadienyl rare-earth-metal clusters with distinct nuclearity. Depending on the halogenido ion size the homometallic clusters Cp′LaCl2]10 and Cp′LaX2]12 (X=Br, I) could be isolated, whereas different crystallization techniques led to the aggregation of clusters of distinct structural motifs, including the desilylated cyclopentadienyl-bridged cluster (μ-Cp)2Cp′8La8I14] and the heteroaluminato derivative Cp′10La10Br18(AlBr2Me2)2]. The use of the Cp′ ancillary ligand facilitates cluster characterization by means of NMR spectroscopy. |
| |
| Keywords: | clusters cyclopentadienyl halogenido lanthanum self-assembly |
|
|
