Field-Induced SMM and Vis/NIR Luminescence on Mononuclear Lanthanide Complexes with 9-Anthracenecarboxylate and 2,2′:6,2″-Terpyridine

Mohamed Salah El Fallah,Saskia Speed,Oriol Porcar,Berta Casanovas,Ramon Vicente,Mercè Font-Bardía

doi:10.3390/magnetochemistry7090124

Abstract

Five new mononuclear lanthanide complexes are synthesized by adding the several lanthanide nitrate hexahydrate salts, which for lanthanide (Ln) are Eu, Tb, Dy, Er, and Yb, with 9-anthracenecarboxylic acid (9-Hanthc) and 2,2′:6,2″-terpyridine (TPY) in mixed solution of methanol and dimethylformamide (DMF). The general formula is [Eu(9-anthc)3(TPY)(DMF)]·H2O (1Eu) where Eu(III) is ennea-coordinated or [Ln(9-anthc)3(TPY)(H2O)]·H2O·DMF (Ln = Tb (2Tb), Dy (3Dy), Er (4Er), and Yb (5Yb)) where Ln(III) is octa-coordinated. For compounds 3Dy, 4Er, and 5Yb, the dynamic ac magnetic study indicated field-induced single molecule magnet (SMM) behavior. The photoluminescence studies in the solid state of these complexes show the sensitization of 4f-4f transitions for 4Er and 5Yb in the NIR region.

Highlights

In recent years, coordination complexes with lanthanide ions have been extensively studied because of their interesting magnetic and luminescent properties
The magnetic interest arises from the high magnetic momentum of the lanthanide ions and strong magnetic anisotropy of its ground state widely used in the molecular magnetism area to design single-molecule magnets (SMMs) that provide potential in information storage, quantum computation, and spintronics [1,2,3,4,5,6,7,8]
The magnetic relaxation occurs through different process such as Orbach one, direct relaxation, Raman mechanism, or Quantum Tunneling of the Magnetization (QTM)

Summary

Introduction

Coordination complexes with lanthanide ions have been extensively studied because of their interesting magnetic and luminescent properties. In SMMs lanthanide compounds, the energy needed to reverse the magnetization, and the gaps energy between the emission contributions, result in the sublevel structure of the Stark components. The magnetic relaxation occurs through different process such as Orbach one, direct relaxation, Raman mechanism, or Quantum Tunneling of the Magnetization (QTM). In many cases, these processes can occur conjunctly. One of the used strategies to better understand the magnetic properties is to take advantage of the correlation between the magnetic and optical properties of the luminescent SMM compounds

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Conclusion