Lanthanoid Coordination Polymers Based on Homoditopic Picolinate Ligands: Synthesis, Structure and Magnetic Properties

A ditopic ligand (H<sub>2</sub><b>L<sub>1</sub></b>), containing picolinate subunits segmented by ethynylene bridges, has been used in the synthesis of a series of isostructural coordination polymers, formulated as [(CH<sub>3</sub>)<sub>2</sub...

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Bibliographic Details
Main Authors: Verónica Jornet-Mollá, Carlos J. Gómez-García, Miquel J. Dolz-Lozano, Francisco M. Romero
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Magnetochemistry
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Online Access:https://www.mdpi.com/2312-7481/11/4/31
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Summary:A ditopic ligand (H<sub>2</sub><b>L<sub>1</sub></b>), containing picolinate subunits segmented by ethynylene bridges, has been used in the synthesis of a series of isostructural coordination polymers, formulated as [(CH<sub>3</sub>)<sub>2</sub>NH<sub>2</sub>][Ln(<b>L<sub>1</sub></b>)<sub>2</sub>]·H<sub>2</sub>O·CH<sub>3</sub>COOH, where Ln = Eu (<b>1</b>), Gd (<b>2</b>), Tb (<b>3</b>), Dy (<b>4</b>) and Ho (<b>5</b>). The single-crystal structures show that these compounds crystallise in the orthorhombic <i>Pna</i>2<sub>1</sub> space group and form 3D anionic lattices with triangular cavities. AC magnetic susceptibility measurements show that the Gd, Tb and Dy derivatives (<b>2</b>–<b>4</b>) present a slow relaxation in their magnetisation under an applied DC magnetic field. The detailed study of the AC susceptibility in compounds <b>2</b> and <b>4</b> shows that they relax following direct and Orbach mechanisms under these conditions. The Dy derivative (<b>4</b>) retains this behaviour in the absence of an external field, relaxing via quantum tunnelling and Orbach mechanisms. Compound <b>2</b> is one of the very few reported Gd(III) compounds showing slow relaxation in its magnetisation.
ISSN:2312-7481