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Regueiro A, Martí-Carrascosa M, Torres-Cavanillas R, Coronado E. Unlocking room-temperature bistable spin transition at the nanoscale: the synthesis of core@shell [Fe(NH 2trz) 3(NO 3) 2]@SiO 2 nanoparticles. Dalton Trans 2024; 53:8764-8771. [PMID: 38712733 DOI: 10.1039/d4dt00911h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
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.
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Affiliation(s)
- A Regueiro
- Instituto de Ciencia Molecular, Universitat de València, Catedrático José Beltrán 2, 46980, Paterna, Spain.
| | - M Martí-Carrascosa
- Instituto de Ciencia Molecular, Universitat de València, Catedrático José Beltrán 2, 46980, Paterna, Spain.
- Universitat Politecnica de Valencia, Nanophotonics Technology Center, Valencia, Spain
| | - R Torres-Cavanillas
- Instituto de Ciencia Molecular, Universitat de València, Catedrático José Beltrán 2, 46980, Paterna, Spain.
- Department of Materials, Oxford University, 21 Banbury Rd, Oxford OX2 6NN, UK.
| | - E Coronado
- Department of Materials, Oxford University, 21 Banbury Rd, Oxford OX2 6NN, UK.
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Kilic MS, Brehme J, Pawlak J, Tran K, Bauer FW, Shiga T, Suzuki T, Nihei M, Sindelar RF, Renz F. Incorporation and Deposition of Spin Crossover Materials into and onto Electrospun Nanofibers. Polymers (Basel) 2023; 15:polym15102365. [PMID: 37242940 DOI: 10.3390/polym15102365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 05/28/2023] Open
Abstract
We synthesized iron(II)-triazole spin crossover compounds of the type [Fe(atrz)3]X2 and incorporated and deposited them on electrospun polymer nanofibers. For this, we used two separate electrospinning methods with the goal of obtaining polymer complex composites with intact switching properties. In view of possible applications, we chose iron(II)-triazole-complexes that are known to exhibit spin crossover close to ambient temperature. Therefore, we used the complexes [Fe(atrz)3]Cl2 and [Fe(atrz)3](2ns)2 (2ns = 2-Naphthalenesulfonate) and deposited those on fibers of polymethylmethacrylate (PMMA) and incorporated them into core-shell-like PMMA fiber structures. These core-shell structures showed to be inert to outer environmental influences, such as droplets of water, which we purposely cast on the fiber structure, and it did not rinse away the used complex. We analyzed both the complexes and the composites with IR-, UV/Vis, Mössbauer spectroscopy, SQUID magnetometry, as well as SEM and EDX imaging. The analysis via UV/Vis spectroscopy, Mössbauer spectroscopy, and temperature-dependent magnetic measurements with the SQUID magnetometer showed that the spin crossover properties were maintained and were not changed after the electrospinning processes.
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Affiliation(s)
- Maximilian Seydi Kilic
- Institute of inorganic Chemistry, Leibniz Universität Hannover, Callinstraße 7, 30167 Hannover, Germany
| | - Jules Brehme
- Institute of inorganic Chemistry, Leibniz Universität Hannover, Callinstraße 7, 30167 Hannover, Germany
- Faculty II, Hochschule Hannover, University of Applied Science an Arts, Ricklinger Stadtweg 120, 30459 Hannover, Germany
- Hannover School for Nanotechnology, Laboratorium für Nano-und Quantenengineering (LNQE), Leibniz Universität Hannover, Schneiderberg 39, 30167 Hannover, Germany
| | - Justus Pawlak
- Institute of inorganic Chemistry, Leibniz Universität Hannover, Callinstraße 7, 30167 Hannover, Germany
- Hannover School for Nanotechnology, Laboratorium für Nano-und Quantenengineering (LNQE), Leibniz Universität Hannover, Schneiderberg 39, 30167 Hannover, Germany
| | - Kevin Tran
- Institute of inorganic Chemistry, Leibniz Universität Hannover, Callinstraße 7, 30167 Hannover, Germany
- Hannover School for Nanotechnology, Laboratorium für Nano-und Quantenengineering (LNQE), Leibniz Universität Hannover, Schneiderberg 39, 30167 Hannover, Germany
| | - Friedrich Wilhelm Bauer
- Faculty II, Hochschule Hannover, University of Applied Science an Arts, Ricklinger Stadtweg 120, 30459 Hannover, Germany
| | - Takuya Shiga
- Graduate School of Pure and Applied Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8577, Ibaraki, Japan
| | - Taisei Suzuki
- Graduate School of Pure and Applied Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8577, Ibaraki, Japan
| | - Masayuki Nihei
- Graduate School of Pure and Applied Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba 305-8577, Ibaraki, Japan
| | - Ralf Franz Sindelar
- Faculty II, Hochschule Hannover, University of Applied Science an Arts, Ricklinger Stadtweg 120, 30459 Hannover, Germany
- Hannover School for Nanotechnology, Laboratorium für Nano-und Quantenengineering (LNQE), Leibniz Universität Hannover, Schneiderberg 39, 30167 Hannover, Germany
| | - Franz Renz
- Institute of inorganic Chemistry, Leibniz Universität Hannover, Callinstraße 7, 30167 Hannover, Germany
- Hannover School for Nanotechnology, Laboratorium für Nano-und Quantenengineering (LNQE), Leibniz Universität Hannover, Schneiderberg 39, 30167 Hannover, Germany
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