An air-stable high-performance single-molecule magnet operating as a luminescent thermometer below its blocking temperature

abstract

The field of molecule magnets has advanced significantly in recent years. Yet, key challenges persist for their practical applications, such as achieving higher blocking temperatures and maintaining precise temperature control in air-stable magnets. This work addresses aspects related to both challenges. Thus, it presents the air-stable hexagonal bipyramidal compound {[Dy(LN6en)(OSiPh3)2](BPh4)}1.5CH2Cl2 (11.5CH2Cl2) and its diluted analogue {[Dy0.1Y0.9(LN6en)(OSiPh3)2](BPh4)}1.5CH2Cl2 (1@Y1.5CH2Cl2). Their high axiality, achieved by reducing equatorial charge, enables magnetic behaviour with energy barriers higher than 1500 K and blocking temperatures based on hysteresis (THB) of 12 and 40 K, respectively. Hence, 1@Y1.5CH2Cl2 is the SMM with the highest THB reported among air-stable uncapsulated molecule magnets. Besides, both complexes show temperature-dependent luminescence. Remarkably, 1@Y1.5CH2Cl2 stands out as the pioneering example of a bifunctional molecule magnet and luminescent thermometer with both functionalities active below its THB. This breakthrough makes it possible to monitor the temperature of a molecule in the range where it exhibits remanent magnetization for the first time. Moreover, this molecular material presents by far the best magnetic characteristics (Ueff and THB) of any SMM luminescent thermometer reported to date. Experimental magnetic and luminescent data are analysed using theoretical calculations. Notably, luminescence is interpreted via coupled cluster methods, offering a more sophisticated alternative to the traditional time-dependent DFT approach.

keywords

SLOW RELAXATION; MAGNETIZATION; EXCHANGE

subject category

Chemistry

authors

Corredoira-Vazquez, J; Gonzalez-Barreira, C; Fondo, M; Garcia-Deibe, AM; Sanmartin-Matalobos, J; Gómez-Coca, S; Ruiz, E; Brites, CDS; Carlos, LD

Groups

G2 - Photonic, Electronic and Magnetic Materials

Projects

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

acknowledgements

This work was supported by Universidade de Santiago de Compostela (2024-PU027-1), Conselleria de Cultura, Educacion, Formacion Profesional e Universidades, Xunta de Galicia (convenio 2023-1298), by Portuguese funds through the FCT/MCTES (PIDDAC) (UIDB/50011/2020, https://doi.org/10.54499/UIDB/50011/2020; UIDP/50011/2020, https://doi.org/10.54499/UIDP/50011/2020; and LA/P/0006/2020, https://doi.org/10.54499/LA/P/0006/2020 projects of the CICECO-Aveiro Institute of Materials), and by Ministerio de Ciencia, Innovacion y Universidades (PID2021-122464NB-I00 and Maria de Maeztu CEX2021-001202-M). This article is based upon work from COST Action CA22131, supported by COST (European Cooperation in Science and Technology). J. C. V. also thanks Xunta de Galicia for his postdoctoral fellowship (ED481B-2022-068). We also acknowledge the Generalitat de Catalunya for the 2021-SGR-00286 grant and E. R. for an ICREA Academia grant. We thank CSUC and BSC supercomputer centres for the computational resources.