Syntheses and crystal structures of triindenyllanthanide complexes (η 5-C 9H 7) 3Ln · OC 4H 8 (Ln  Nd, Gd, Er)

Abstract

The complexes named in the title (η 5-C 9H 7) 3Ln·OC 4H 8 (Ln  Nd, Gd, Er) were synthesized by the reaction of anhydrous lanthanide trichlorides with indenyl potassium and cyclooctadienyl potassium (1:2:1 molar ratio) in THF. The complexes were characterized by elemental analysis, infrared and 1H-NMR spectroscopy, and mass spectrometry. In addition, the crystal structures of (η 5-C 9H 7) 3Nd·OC 4H 8 ( 1) and (η 5-C 9H 7) 3Gd·OC 4H 8 ( 2) were determined by an X-ray diffraction study. Complexes 1 and 2 belong to hexagonal space group P6 3 with unit cell parameters a = b = 11.843(3), c = 10.304(4) Å, V = 1251.7(9) Å 3, D c = 1.49 g·cm −, Z = 2 for 1, and a = b = 11.805(2), c = 10.236(2) Å, V = 1235.4(6) Å 3, D c = 1.54 g· −3, Z = 2 for 2. The structures were solved by Patterson and Fourier techniques and refined by least-squared to final discrepancy indices of R = 0.049, R w = 0.053 using 925 independent reflections with I ⩾ 3σ( I for 1, and R = 0.23, R w = 0.025 using 1327 independent reflections with I ⩾ 3σ( I) for 2. Coordination numbers for Nd 3+ and Gd 3+ are 10; the average bond lengths NdO and GdO are 2.557(21) and 2.459(13) Å, respectively. The structural studies showed the complexes to have 3-fold symmetry, but the THF molecule has no such symmetry; consequently the arrangement of carbon atoms in the THF molecule are disordered.