Lanthanoid Tetramethylaluminates and Their Paramagnetic NMR Parameters

作者：Nieland Anja; Mix Andreas; Neumann Beate; Stammler Hans Georg; Mitzel Norbert W^*

来源：European Journal of Inorganic Chemistry, 2014, 2014(1): 51-57.

DOI：10.1002/ejic.201301266

• Lanthanoids
• Aluminum
• Holmium
• Magnetic properties
• NMR spectroscopy

Tris(tetramethylaluminate)s of the lanthanoids cerium (1), holmium (2), and erbium (3) were synthesized by treating lanthanoid amide complexes of the type [Ln(NMe2)(3)(LiCl)(3)] with an excess amount of AlMe3. These compounds were characterized by single-crystal X-ray diffraction, elemental analysis, and NMR spectroscopy. Paramagnetic NMR spectroscopic studies were undertaken to investigate the influence of the compounds on the solvent chemical shifts. NMR parameters for the H-1, C-13, and Al-27 nuclei of all the reported lanthanoid tris(tetramethylaluminate)s were measured. The reactions of tris(tetramethylaluminate)s of samarium and holmium with an excess amount of tetrahydrofuran led to [LnMe(2)(thf)(5)][AlMe4] {Ln = Ho (4), Sm (5)}. NMR spectroscopic investigations of the paramagnetic holmium and samarium methyl compounds (i.e., 4, 5) as well as the known diamagnetic analogue [YMe2(thf)(5)][AlMe4] revealed methyl group exchange processes in solution.

• 出版日期2014-1