Organolanthanide chemistry with bis(trimethylsilyl)methyl- and tert-butyldimethylsilyl-substituted cyclopentadienyl ligands. Synthesis and characterisation of tris(cyclopentadienyl)lanthanide(III) complexes, including crystal structures of [Ln{#eta#~

摘要

The homoleptic tris(substituted cyclopentadienyl)lanthanide(III) complexes [LnCp_3~R] (Ln = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Gd (6), Tb (7), Dy (8), Er (9), Tm (10) and Yb (11)], [NbCp_3~t] (12), [CeCp_3~(tt)] (13) and [NdCp_3~(tt)] (14) [Cp~R = #eta#~5-C_5H_4{CH(SiMe_3)_2, Cp~t = #eta#~5-C_5H_4(SiMe_2Bu~t), Cp~(tt) = #eta#~5-C_5H_3(SiMe_2Bu~t)_2-1,3], have been synthesised by the reaction of the anhydrous lanthanide(III) halide with the appropriate sodium or potassium cyclopentadienide in THF. The characterisation of these complexes was established by ~1H-, ~(13)C- and ~(29)Si-NMR spectroscopy (for 1-5 and 12-14), elemental analysis and mass spectrometry. The early paramagnetic lanthanide complexes 2-5, and 12-14 had very sharp ~1H-NMR spectral signals, and the paramagnetic shifts were temperature-dependent. The molecular structures of 4, 10 and 13 have been determined by single crystal X-ray diffraction studies. The attempted syntheses of organoneodymium(II) and organothulium(II) complexes are also described.