Issue 20, 2024

Unlocking room-temperature bistable spin transition at the nanoscale: the synthesis of core@shell [Fe(NH2trz)3(NO3)2]@SiO2 nanoparticles

Abstract

In this work, we address the synthesis of stable spin-crossover nanoparticles capable of undergoing a hysteretic spin transition at room temperature. For this purpose, we use the reverse-micelle protocol to prepare naked [Fe(NH2trz)3](NO3)2 and core@shell [Fe(NH2trz)3](NO3)2@SiO2 nanoparticles. Through meticulous adjustment of synthetic parameters, we achieved nanoparticle sizes ranging from approximately 40 nm to 60 nm. Our findings highlight that [Fe(NH2trz)3](NO3)2 presents a modest thermal hysteresis of 7 K, which decreases by downsizing. Conversely, silica-coated nanoparticles with sizes of ca. 60 and 40 nm demonstrate a remarkable hysteretic response of approximately 30 K, switching their spin state around room temperature. Moreover, the presence of a SiO2 shell substantially enhances the nanoparticles’ stability against oxidation. In this context, the larger 60 nm [Fe(NH2trz)3](NO3)2@SiO2 hybrid remains stable in water for up to two hours, enabling the observation of an unreported water-induced spin transition after 30 min. Therefore, this work also introduces an intriguing avenue for inducing spin transitions through solvent exchange, underscoring the versatility and potential of these nanoparticles.

Graphical abstract: Unlocking room-temperature bistable spin transition at the nanoscale: the synthesis of core@shell [Fe(NH2trz)3(NO3)2]@SiO2 nanoparticles

Supplementary files

Article information

Article type
Paper
Submitted
27 mar 2024
Accepted
29 apr 2024
First published
30 apr 2024
This article is Open Access
Creative Commons BY license

Dalton Trans., 2024,53, 8764-8771

Unlocking room-temperature bistable spin transition at the nanoscale: the synthesis of core@shell [Fe(NH2trz)3(NO3)2]@SiO2 nanoparticles

A. Regueiro, M. Martí-Carrascosa, R. Torres-Cavanillas and E. Coronado, Dalton Trans., 2024, 53, 8764 DOI: 10.1039/D4DT00911H

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