Issue 41, 2018

Synthesis and molecular structure of pentadienyl complexes of the rare-earth metals

Abstract

The coordination chemistry of the sterically encumbered pentadienyl ligand pdl′ (pdl′ = 2,4-(Me3C)2C5H5) towards a series of rare-earth metals was systematically explored and the resulting metal complexes were fully characterized by several techniques including X-ray diffraction, elemental analysis, NMR spectroscopy and solid-state magnetic susceptibility studies. Three different reaction products were isolated depending on the redox-potentials and ionic radii of the metal atoms. They can be classified as (a) salt-metathesis, (b) metal reduction–ligand oxidation and (c) ligand deprotonation products. While for the larger and difficult to reduce metal ions, M = La, Ce, Pr and Nd, trivalent compounds [(η5-pdl′)3M] (1-M) were isolated, for the more readily reduced metal ions the corresponding divalent compounds [[(η5-pdl′)2M(thf)n] (2-M; with M = Sm (n = 2); Eu, Yb (n = 1)) were formed. A more complex structural motif was observed for the smaller and also difficult to reduce metal ions, M = Sc, Y, Gd, Tb, Dy, Ho, Er, Tm and Lu, which yielded the bimetallic complexes of the type [(pdl′)(pdl′−1H)(pdl′−2H)M2(thf)2] (3-M). In these dimeric complexes the pdl′ ligand acts as a result of deprotonation reactions not only as a monoanionic [pdl′], but also as a dianionic [pdl′−1H]2− and a trianionic [pdl′−2H]3− ligand scaffold, which form unusual structural motifs including a six-membered metallacycle. Solid-state magnetic susceptibility studies revealed the expected free-ion magnetic moments at T = 300 K for all investigated compounds, whereas at lower temperatures crystal-field effects dominate. Furthermore, for 3-Gd, 3-Tb, 3-Dy and 3-Er weak ferromagnetic exchange interactions were observed at low temperature.

Graphical abstract: Synthesis and molecular structure of pentadienyl complexes of the rare-earth metals

Supplementary files

Article information

Article type
Paper
Submitted
31 ጁላይ 2018
Accepted
29 ኦገስ 2018
First published
07 ሴፕቴ 2018

Dalton Trans., 2018,47, 14468-14482

Synthesis and molecular structure of pentadienyl complexes of the rare-earth metals

J. Raeder, M. Reiners, R. Baumgarten, K. Münster, D. Baabe, M. Freytag, P. G. Jones and M. D. Walter, Dalton Trans., 2018, 47, 14468 DOI: 10.1039/C8DT03123A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements