New Cyclopentadienyl-N-Silylphosphazene Complexes of Rare-Earth Metals Yttrium and Lutetium

作者：Hillesheim Nina S; Elfferding Michael; Linder Thomas; Sundermeyer Joerg^*

来源：Zeitschrift fur Anorganische und Allgemeine Chemie, 2010, 636(9-10): 1776-1782.

DOI：10.1002/zaac.201000078

• Constrained Geometry complexes
• Cyclopentadienyl ligands
• Phosphazenes
• Rare earths
• Silicon

We report the investigation of four new monoanionic cyclopentadienyl-N-silylphosphazene ligands [C(5)R(4)-SiMe(2)-NPR'(3)](-) (CpSiNP(-)) 1-4. In this system the amido moiety of the classical dianionic dictate ligand (CpSiN(2-)) is displaced by an isoelectronic phosphazene donor CpSiNP(-)). The iminophosphorane-functionalized tetramethylcyclopentadiene ligands have been prepared by the reaction of two equivalents of tris(tert-butyl)iminophosphorane or tris(dimethylamino)iminophosphorane with tetramethyl or tert-butyl-substituted chlorodimethylsilyl-1,3-cyclopentadiene. The molecular structures of the protonated species of two representatives 1-H and 2-H were established by X-ray diffraction analysis. Furthermore the metallation of the ligand [C(5)R(4)-SiMe(2)-NPtBu(3)]H (2-H) was explored by the aryl elimination pathway using chelate stabilized arene complexes of rare-earth metals (RE) [RE(dmba)(3)][RE = Y, Lu; (dmba(-)) = ortho-metalated N,N-dimethylbenzylamine]. The resulting cyclopentadienyl diaryl complexes of the type [eta(5)-C(5)Me(4)-SiMe(2)-NPtBu(3))RE(dmba)(2)] [RE = Y (5); Lu(6)] were completely characterized by NMR spectroscopy, elemental analysis and X-ray diffraction analysis. The coordination number of the central atom in each case is nine. Five RE-C bonds to the Cp fragment, two RE-C bonds to the aryl-carbon atom and two RE-N bonds to the chelating amino function are realized. The phosphazene unit with uncommonly large Si-N-P angles of 173 degrees (5) and 166 degrees (6) do not form a bond in terms of the Constrained-Geometry ligand concept at least in these complexes. It seems that on the one hand the high coordination number and on the other hand the stable chelate structure of the coordinated amino-aryl ligand is responsible for this result.

• 出版日期2010