Spin Crossover Phenomenon in Nanocrystals and Nanoparticles of [Fe(3-Fpy)2M(CN)4] (MII = Ni, Pd, Pt) Two-Dimensional Coordination Polymers

The two-dimensional spin crossover (SCO) polymers [Fe(3-Fpy)2M(CN)4] (MII = Ni(1), Pd(2), Pt(3)) were nanostructured in the form of nanocrystals and nanoparticles, and their chemical, structural, and physical characterization was carried out using different experimental methods (powder X-ray diffrac...

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Bibliographic Details
Published in:Chemistry of materials 2010-07, Vol.22 (14), p.4271-4281
Main Authors: Martínez, Víctor, Boldog, Ishtvan, Gaspar, Ana Belén, Ksenofontov, Vadim, Bhattacharjee, Ashis, Gütlich, Philipp, Real, José Antonio
Format: Article
Language:English
Subjects:
Magnetic Materials
Nanomaterials (Nanops, Nanotubes, etc.)
Sensors
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Summary:The two-dimensional spin crossover (SCO) polymers [Fe(3-Fpy)2M(CN)4] (MII = Ni(1), Pd(2), Pt(3)) were nanostructured in the form of nanocrystals and nanoparticles, and their chemical, structural, and physical characterization was carried out using different experimental methods (powder X-ray diffraction, magnetic susceptibility measurements, Mössbauer and infrared spectroscopy, transmission and scanning electronic microscopy, etc.). Surfactant-free nanocrystals of average dimensions 400 × 400 × 30 nm (1a, 1a*, 2a, 3a) were synthesized from water in oil microemulsions (w/o) while nanoparticles of average size 200 × 100, 100 × 60, and 70 × 30 nm were obtained in poly(vinylpyrrolidone) (PVP) coating polymer (1b−1d, 2b, 2b′, and 3b). The spin crossover process is drastically influenced by the dimensions of the crystal/particle. Nanocrystals of 1−3 exhibit a quasi complete first-order spin transition centered within the interval 200−225 K, while PVP-coated nanoparticles undergo continuous second order spin transition at much lower temperatures (ca. 160 K).
ISSN:0897-4756
1520-5002
DOI:10.1021/cm101022u