Monitoring of Fe(II) Spin Transition in Cu(II)-Doped Spin-Crossover Nanoparticles

Experimental protocols based on Electron Paramagnetic Resonance (EPR) and Raman spectroscopy are presented for the investigation of the Fe(II) spin transition in Cu(II)-doped 1-D spin-crossover (SCO) nanoparticles of the type [Fe<sub>1−x</sub>Cu<sub>x</sub>(NH<sub>2<...

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Main Authors: Alexander Charitos, Vassilis Tangoulis, John Parthenios, Ondrej Malina, Radim Mach, Nikolaos Ioannidis, Nikolia Lalioti
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/30/6/1258
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author Alexander Charitos
Vassilis Tangoulis
John Parthenios
Ondrej Malina
Radim Mach
Nikolaos Ioannidis
Nikolia Lalioti
author_facet Alexander Charitos
Vassilis Tangoulis
John Parthenios
Ondrej Malina
Radim Mach
Nikolaos Ioannidis
Nikolia Lalioti
author_sort Alexander Charitos
collection DOAJ
description Experimental protocols based on Electron Paramagnetic Resonance (EPR) and Raman spectroscopy are presented for the investigation of the Fe(II) spin transition in Cu(II)-doped 1-D spin-crossover (SCO) nanoparticles of the type [Fe<sub>1−x</sub>Cu<sub>x</sub>(NH<sub>2</sub>trz)<sub>3</sub>]Br<sub>2</sub> where x = 0.03 and 0.06 and NH<sub>2</sub>trz = 4-amino-1, 2, 4-triazole. The resulting nanoparticles were characterized using Transmission Electron Microscopy (TEM), Infrared (IR) spectroscopy, and powder X-ray diffraction (p-XRD). Magnetic susceptibility measurements revealed a dependence on the scan rate, with critical temperatures and hysteresis widths varying accordingly. EPR spectroscopy provided insights into the doped nanoparticles’ structural changes and spin-state transitions. The Cu(II) dopants exhibited significant g-factor anisotropy and hyperfine structure, indicative of a distorted octahedral coordination. The EPR spectra indicated that the spin transition occurs in domains populated by ions of the same spin state. Cu(II) ions show different spectral characteristics depending on whether they are in high-spin or low-spin domains of Fe(II). Changes in Raman bands induced by laser power reveal structural and electronic rearrangements during the LS to HS transition. The findings provide insights into metal–ligand interactions and the molecular mechanisms underlying the SCO process.
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spelling doaj-art-596f60260636495ab8a9a9bdf2b573e12025-08-20T01:48:48ZengMDPI AGMolecules1420-30492025-03-01306125810.3390/molecules30061258Monitoring of Fe(II) Spin Transition in Cu(II)-Doped Spin-Crossover NanoparticlesAlexander Charitos0Vassilis Tangoulis1John Parthenios2Ondrej Malina3Radim Mach4Nikolaos Ioannidis5Nikolia Lalioti6Laboratory of Inorganic Chemistry, Department of Chemistry, University of Patras, 26504 Patras, GreeceLaboratory of Inorganic Chemistry, Department of Chemistry, University of Patras, 26504 Patras, GreeceInstitute of Chemical Engineering Sciences (ICE-HT), Foundation for Research and Technology-Hellas (FORTH), 26504 Patras, GreeceRegional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech RepublicRegional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech RepublicInstitute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 15310 Athens, GreeceLaboratory of Inorganic Chemistry, Department of Chemistry, University of Patras, 26504 Patras, GreeceExperimental protocols based on Electron Paramagnetic Resonance (EPR) and Raman spectroscopy are presented for the investigation of the Fe(II) spin transition in Cu(II)-doped 1-D spin-crossover (SCO) nanoparticles of the type [Fe<sub>1−x</sub>Cu<sub>x</sub>(NH<sub>2</sub>trz)<sub>3</sub>]Br<sub>2</sub> where x = 0.03 and 0.06 and NH<sub>2</sub>trz = 4-amino-1, 2, 4-triazole. The resulting nanoparticles were characterized using Transmission Electron Microscopy (TEM), Infrared (IR) spectroscopy, and powder X-ray diffraction (p-XRD). Magnetic susceptibility measurements revealed a dependence on the scan rate, with critical temperatures and hysteresis widths varying accordingly. EPR spectroscopy provided insights into the doped nanoparticles’ structural changes and spin-state transitions. The Cu(II) dopants exhibited significant g-factor anisotropy and hyperfine structure, indicative of a distorted octahedral coordination. The EPR spectra indicated that the spin transition occurs in domains populated by ions of the same spin state. Cu(II) ions show different spectral characteristics depending on whether they are in high-spin or low-spin domains of Fe(II). Changes in Raman bands induced by laser power reveal structural and electronic rearrangements during the LS to HS transition. The findings provide insights into metal–ligand interactions and the molecular mechanisms underlying the SCO process.https://www.mdpi.com/1420-3049/30/6/1258Fe-triazolespin crossoverEPRRamanthermal hysteresis
spellingShingle Alexander Charitos
Vassilis Tangoulis
John Parthenios
Ondrej Malina
Radim Mach
Nikolaos Ioannidis
Nikolia Lalioti
Monitoring of Fe(II) Spin Transition in Cu(II)-Doped Spin-Crossover Nanoparticles
Molecules
Fe-triazole
spin crossover
EPR
Raman
thermal hysteresis
title Monitoring of Fe(II) Spin Transition in Cu(II)-Doped Spin-Crossover Nanoparticles
title_full Monitoring of Fe(II) Spin Transition in Cu(II)-Doped Spin-Crossover Nanoparticles
title_fullStr Monitoring of Fe(II) Spin Transition in Cu(II)-Doped Spin-Crossover Nanoparticles
title_full_unstemmed Monitoring of Fe(II) Spin Transition in Cu(II)-Doped Spin-Crossover Nanoparticles
title_short Monitoring of Fe(II) Spin Transition in Cu(II)-Doped Spin-Crossover Nanoparticles
title_sort monitoring of fe ii spin transition in cu ii doped spin crossover nanoparticles
topic Fe-triazole
spin crossover
EPR
Raman
thermal hysteresis
url https://www.mdpi.com/1420-3049/30/6/1258
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