Multifunctional luminescent magnetic cryocooler in a Gd₅Mn₂ pyramidal complex

Abstract

Magnetic cooling is a highly efficient refrigeration technique with the potential of replacing expensive and rare helium-3 in the field of ultra-low temperature cooling. However, the visualization of a cryogen at an extremely low temperature and in a strong magnetic field is challenging, but it is crucial for the precise positioning and in situ thermal probe measurements in potential practical applications. Here, the activation of a red-emissive Mn(ii) ion using 3d/4f chemistry produces a luminescent molecule cooler, [Gd5Mn2(LOMe)2(OH)4(Ac)6(MeOH)10Cl2]Cl3·2MeOH (1), with the core of an Mn(ii)-anchored heptanuclear [GdIII5MnII2] pyramid. The photoluminescence (PL) of the Mn2+ emission, with a large Stokes shift (λem ∼ 690 nm) from 4T1(4G) → 6A1(6S), shows not only a sensitive temperature sensing property but also reversible mechanoluminescence (ML). More attractively, these findings reveal a considerable magnetocaloric effect (MCE) coupled with a tunable emission window, opening up new opportunities in the multifunctional applications of PL, ML, and the MCE involving red-light sources, thermometers, and stress imaging. In particular, this provides a novel resolution to design visualized PL coolers.

Hexanuclear Co4Dy2, Zn4Dy2, and Co4Y2 Complexes with Defect Tetracubane Cores: Syntheses, Structures, and Magnetic Properties

“…The chemistry of polynuclear 3d–4f clusters continues to be an active research field. The motivations of the scientists are mainly driven by the aesthetically pleasing structures of these compounds, [1–6] and their potential applications in catalysis, electrochemistry, and luminescence materials [7–15] . In recent years, particular attention has been devoted to 3d–4f single molecule magnets (SMMs) [16–19] .…”

Selective Coordination of Self-Assembled Hexanuclear [Ni4Ln2] and [Ni2Mn2Ln2] (Ln = DyIII, TbIII, and HoIII) Complexes: Stepwise Synthesis, Structures, and Magnetic Properties

“…In recent years, the incorporation of multiple spin carriers within a single molecular entity is a useful approach to obtaining a new family of single-molecule magnets (SMMs). − Such complexes can be obtained from binucleating ligand systems having dissimilar and adjacent coordination pockets. , The synthesis and study of such coordination complexes comprising different 3d metal ions have generated huge interest over the last three decades. − Among the multinuclear 3d metal-ion-based SMMs, the phenoxido-bridged high-spin Mn III and Ni II aggregates are interesting, where high-spin octahedral Mn III complexes usually exhibit significant magnetic anisotropy upheld by Jahn–Teller distortion. Thus, the involvement of these two 3d metal ions within a single molecular entity can establish a new identity with promise for molecular magnetism. − Over the past 20 years, the involvement of 4f metal ions along with the 3d metal ion, using terminal −OMe functionalities bearing Schiff bases, has attracted huge attention for the synthesis of a new family of 3d–4f complexes. − These groups of multinuclear coordination aggregates of different 3d and 4f ions have potential applications such as high-density information storage, quantum computing, luminescence, and molecular spintronics . Often high-nuclearity aggregates achieve high ground-state spin ( S ) but show poor magnetic anisotropy ( D ), resulting in the absence of SMM behavior .…”

“…11−13 Over the past 20 years, the involvement of 4f metal ions along with the 3d metal ion, using terminal −OMe functionalities bearing Schiff bases, has attracted huge attention for the synthesis of a new family of 3d−4f complexes. 14−17 These groups of multinuclear coordination aggregates of different 3d and 4f ions have potential applications such as high-density information storage, 18 quantum computing, 19 luminescence, 20 and molecular spin-tronics. 21 Often high-nuclearity aggregates achieve high ground-state spin (S) but show poor magnetic anisotropy (D), resulting in the absence of SMM behavior.…”

Structural Complexity and Magnetic Orderings in a Large Family of 3d–4f Heterobimetallic Sulfates

“…The investigation of 3d−4f heterobimetallic materials is of scientific and industrial interest due to their potential applicability in a variety of fields, including magnetism, 1 catalysis, 2 photoluminescence, 3 gas storage, 4 and optical sensing. 5 The high magnetic anisotropy and large spin−orbit coupling of lanthanide ions in combination with their ability to engage in strong magnetic exchange interactions with itinerantly ferromagnetic transition metals make them particularly ideal for developing 3d−4f materials with interesting magnetic properties.…”