Magnetic and Luminescent Properties of Isostructural 2D Coordination Polymers Based on 2-Pyrimidinecarboxylate and Lanthanide Ions

Amalia García-García,José M Seco,Ainhoa Goñi-Cárdenas,Duane Choquesillo-Lazarte,Javier Cepeda,Alfonso Salinas-Castillo,Antonio Rodríguez-Diéguez,Andoni Zabala-Lekuona

doi:10.3390/cryst10070571

Amalia García-García, José M Seco + Show 6 more

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https://doi.org/10.3390/cryst10070571

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Journal: Crystals	Publication Date: Jul 2, 2020
Citations: 5	License type: CC BY 4.0

Affiliation: University of Granada, University of the Basque Country

Abstract

A couple of isostructural coordination polymers with the general formula [Ln4(pymca)4(AcO)8]n have been obtained from reactions between pyrimidine-2-carboxylate (pymca) ligand and rare-earth ions (Ln = Dy (1), Nd (2)). These two-dimensional compounds have been characterized and the crystal structures have been solved by single-crystal X-ray diffraction technique, resulting in layers along the bc plane based on pymca and acetate anions that act as bridging ligands between metal atoms. Given that pymca and acetate anions possess carboxylate and hetero-nitrogen groups, it is possible to build a coordination polymer whose metal centers have a nine coordination. Furthermore, static and dynamic magnetic measurements of compound 1 reveal the lack of single molecule-magnet (SMM) behavior in this system due to the following two effects: (i) the ligand field does not stabilize magnetic ground states well separated from excited states, and (ii) anisotropy axes are not collinear, according to results with Magellan software. On another level, luminescent properties of compounds 1 and 2 are attributed to singlet π-π* transitions centered on pymca ligand as corroborated by time-dependent density functional theory (TD-DFT) calculations.

Highlights

Coordination polymers (CPs) are defined as infinite systems built up from metal ions and organic ligands linked via coordination bonds and other weak chemical bonds such as hydrogen bonds, π-π stacking, or van der Waals interactions [1]
Pyrimidine-2-carboxylic acid ligand allowed the formation of two isostructural coordination polymers by varying the metal center
Two isostructural coordination polymers with the general formula [Ln4(pymca)4(AcO)8]n were obtained from reactions between pyrimidine-2-carboxylate ligand and rare-earth ions obtained from reactions between pyrimidine-2-carboxylate ligand and rare-earth ions

Summary

Introduction

Coordination polymers (CPs) are defined as infinite systems built up from metal ions and organic ligands linked via coordination bonds and other weak chemical bonds such as hydrogen bonds, π-π stacking, or van der Waals interactions [1]. These materials have gained considerable attention in recent decades, in particular, lanthanide-based coordination polymers, due to their varied structures [2,3], high coordination numbers, gas storage properties [4], biochemical and medical applications [5], as well as interesting luminescent [6] and magnetic properties [7,8,9]. With the goal to achieve coordination frameworks based on f-block metal centers with local connectivity numbers larger than six, ligands containing carboxylate groups and hetero-nitrogen chemical functions frameworks based on f -block metalboth centers with local connectivity numbers larger than six, ligands have been extensively used groups in the construction of thesechemical novel systems because can containing both carboxylate and hetero-nitrogen functions have both been groups extensively coordinate metal centers in different ways [12,13,14].

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