Bimetallic synergy enables silole insertion into THF and the synthesis of Erbium single‐molecule magnets

De, Siddhartha, Mondal, Arpan, Giblin, Sean R. ORCID: https://orcid.org/0000-0003-1876-8619 and Layfield, Richard A. 2024. Bimetallic synergy enables silole insertion into THF and the synthesis of Erbium single‐molecule magnets. Angewandte Chemie International Edition 63 (13) , e202317678. 10.1002/anie.202317678

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Abstract

The potassium silole K2[SiC4‐2,5‐(SiMe3)2‐3,4‐Ph2] reacts with [M(η8‐COT)(THF)4][BPh4] (M=Er, Y; COT=cyclo‐octatetraenyl) in THF to give products that feature unprecedented insertion of the nucleophilic silicon centre into a carbon‐oxygen bond of THF. The structure of the major product, [(μ‐η8 : η8‐COT)M(μ‐L1)K]∞ (1M), consists of polymeric chains of sandwich complexes, where the spiro‐bicyclic silapyran ligand [C4H8OSiC4(SiMe3)2Ph2]2− (L1) coordinates to potassium via the oxygen. The minor product [(μ‐η8 : η8‐COT)M(μ‐L1)K(THF)]2 (2M) features coordination of the silapyran to the rare‐earth metal. In forming 1M and 2M, silole insertion into THF only occurs in the presence of potassium and the rare‐earth metal, highlighting the importance of bimetallic synergy. The lower nucleophilicity of germanium(II) leads to contrasting reactivity of the potassium germole K2[GeC4‐2,5‐(SiMe3)2‐3,4‐Me2] towards [M(η8‐COT)(THF)4][BPh4], with intact transfer of the germole occurring to give the coordination polymers [{η5‐GeC4(SiMe3)2Me2}M(η8‐COT)K]∞ (3M). Despite the differences in reactivity induced by the group 14 heteroatom, the single‐molecule magnet properties of 1Er, 2Er and 3Er are similar, with thermally activated relaxation occurring via the first‐excited Kramers doublet, subject to effective energy barriers of 122, 80 and 91 cm−1, respectively. Compound 1Er is also analysed by high‐frequency dynamic magnetic susceptibility measurements up to 106 Hz.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy
Additional Information:	License information from Publisher: LICENSE 1: URL: http://creativecommons.org/licenses/by/4.0/
Publisher:	Wiley
ISSN:	1433-7851
Funders:	Engineering and Physical Sciences Research Council
Date of First Compliant Deposit:	23 February 2024
Date of Acceptance:	1 February 2024
Last Modified:	04 Apr 2024 14:10
URI:	https://orca.cardiff.ac.uk/id/eprint/166511

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