Synthesis of Rare-Earth-Metal Iminopyrrolyl Complexes from Alkyl Precursors: Ln→Al N‑Ancillary Ligand Transfer

• Published in: Organometallics 2013-03, Vol.32 (5), p.1199-1208
• Main Authors: Kaneko, Hiroshi, Dietrich, H. Martin, Schädle, Christoph, Maichle-Mössmer, Cäcilia, Tsurugi, Hayato, Törnroos, Karl W, Mashima, Kazushi, Anwander, Reiner
• Format: Article
• Language: English
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om301002n

Protonolysis of [YMe3] n with 2-{(N-2,6-dialkylphenyl)iminomethyl)}pyrroles (alkyl = iPr (L1), Me (L2)) gave homoleptic iminopyrrolyl complexes YL1 3 and YL2 3 as well as the complex [L2YL2,Me]2 containing a dianionic pyrrolaldiminato ligand, formed via methylation of the imino backbone. Treatment of the half-sandwich complex [(C5Me5)YMe2]3 and yttrocene (C5Me5)2YMe(THF) with either 2 or 1 equiv of HL afforded the monomeric complexes (C5Me5)YL2 and (C5Me5)2YL, respectively. The complex (C5Me5)YL2 2 readily underwent Ln→Al iminopyrrolyl ligand transfer in the presence of trimethylaluminum, producing the known (C5Me5)Y(AlMe4)2. Salt metatheses of homoleptic Ln(AlMe4)3 (Ln = Y, La) with KL gave complicated reaction mixtures from which the η5/η1:κ1 pyrrolaldiminato-bridged complex [L1,MeLa(AlMe4)]2 and bis(tetramethylaluminate) complex L2Y(AlMe4)2 could be isolated and crystallographically characterized. Moreover, the solid-state structures of YL2 3, [L2YL2,Me]2, (C5Me5)YL1 2, (C5Me5)2YL1, and L2AlMe2 are presented.