Donor and ate-Coordination in Rare-Earth Metal Bis(dimethylsilyl)amide Complexes

• Published in: European Journal of Inorganic Chemistry 2008-04, Vol.2008 (12), p.2014-2023
• Main Authors: Meermann, Christian, Gerstberger, Gisela, Spiegler, Michael, Törnroos, Karl W., Anwander, Reiner
• Format: Article
• Language: English
• Subjects: Neodymium; Rare-earth metals; Scandium; Silylamide
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.200800050

Complete thf donor exchange is observed when complexes Ln[N(SiHMe2)2]3(thf)2 (Ln = La, Nd) are treated with the monofunctional donor molecules triphenylphosphane oxide, N‐methylimidazole, and 1,3‐dimethylimidazolin‐2‐ylidene. The resulting complexes Ln[N(SiHMe2)2]3(donor)2 exhibit a trigonal‐bipyramidal coordination geometry with the donor molecules located in the apical positions. Bifunctional chelating donors 1,10‐phenanthroline, 1,2‐bis(dimethylphosphanyl)ethane, and N,N,N′,N′‐tetramethylethylenediamine give discrete complexes Ln[N(SiHMe2)2]3(phen) (Ln = Sc, La, Nd), Nd[N(SiHMe2)2]3(dmpe), and La[N(SiHMe2)2]3(tmeda). The phen adducts are isostructural as demonstrated for the large Nd3+ and small Sc3+ centers by X‐ray structure analyses and display a distorted square‐pyramidal coordination geometry in the solid state. The distinct coordination of various donor molecules implies subtle changes of the Si–H bonding which can be straightforwardly examined by NMR and FTIR spectroscopy. Ate complex {Y[N(SiHMe2)2]4Li}2 can be isolated and crystallized from Y(OTf)3–Li[N(SiHMe2)2]–hexane reaction mixtures. Dimerization is accomplished by unusual intermolecular Li···H–Si interactions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) Monofunctional (O=PPh3, N‐MeIm, nhc) and bifunctional chelating donor molecules (phen, dmpe, tmeda) displace both thf ligands in Ln[N(SiHMe2)2]3(thf)2 (Ln = La, Nd) which sensitively affects the stereoelectronic properties of the Ln3+ centers asprobed by the SiH functionality.