On the structure and Mössbauer spectra of ferrous nitroprusside

Reguera, E.; Bertrán, José Fernández; Miranda, J.; Dago, A.

doi:10.1007/bf02320293

Cited by 14 publications

(9 citation statements)

References 11 publications

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“…IR and Mössbauer spectra of divalent transition metal nitroprussides have been reported (Reguera et al , 1993; Gómez et al , 2001, 2004). In nitroprussides the inner iron atom is always found to be in a low spin electronic configuration while the outer metal appears in high spin state.…”

Section: Resultsmentioning

confidence: 99%

Crystal structures of cubic nitroprussides: M[Fe(CN)₅NO]·xH₂O(M=Fe, Co, Ni). Obtaining structural information from the background

Gómez

Rodríguez‐Hernández

Reguera³

2007

Powder Diffr.

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A new structural model is proposed for cubic nitroprussides and the crystal structure for the complex salts of Fe(2+), Co(2+), and Ni(2+) refined in that model. In cubic nitroprussides the building unit, [Fe(CN)5NO]2−, and the assembling metal (M=Fe2+, Co2+, Ni2+), have ¾ occupancy with three formula units per cell (Z=3). This leads to certain structural disorder and to different local environments for the outer metal. The crystallographic results are supported by the Mössbauer and infrared data. The XRD powder patterns, index in a cubic cell (Fm3m space group), show a sinuous background because of diffuse scattering from positional disorder of the metal centers. Because of this, the crystal structures were refined allowing the metal centers to move from the (0,0,0) and (0,0,1/2) positions (away from positional symmetry restrictions). The refinement under these conditions leads to excellent agreement factors (Rwp, Rp, S), good pattern background fitting, and produced a refined structural model consistent with the crystal chemistry of nitroprussides. The studied materials are obtained as hydrates. On heating, the crystal water evolves, and below 100°C an anhydrous phase is obtained, preserving the framework of the original hydrates. The loss of the crystal water leads to cell contraction that represents around 2% of cell volume reduction. On cooling down from room temperature to 77 and 12 K, a slight expansion for the -M-N≡C-Fe-C≡N-M- chain length is observed, suggesting that at low temperature and reduction in the metals charge delocalization on the CN bridges takes place. For M=Fe and Co the crystal structure was also refined for the anhydrous phase at 12, 77, and 300 K.

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Section: Resultsmentioning

confidence: 99%

Crystal structures of cubic nitroprussides: M[Fe(CN)₅NO]·xH₂O(M=Fe, Co, Ni). Obtaining structural information from the background

Gómez

Rodríguez‐Hernández

Reguera³

2007

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“…Surprisingly, Prussian blue analogues of the type M[Fe(CN)5NO] xH20 (M = Mn, Fe, Co, Ni, Cu and Zn) have been investigated by a variety of spec troscopic methods, e.g. electronic absorption [4], in frared absorption [5,6], Mössbauer [7,8] and X-ray photoelectron spectroscopy [9]. However, the ther mal decomposition of M[Fe(CN)5N 0 ] jcH20 has received less attention, although a few Prussian blue analogues have been extensively studied [10].…”

Section: Introductionmentioning

confidence: 99%

Thermal Decomposition of Prussian Blue Analogues of the Type Fe[Fe(CN)₅NO]

Inoue

Narino

Yoshioka

et al. 2000

Zeitschrift Für Naturforschung B

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The structure and properties o f the thermal decomposition products of Fe[Fe(CN)sNO] • x H2O (x = 5~6 ) have been studied by M össbauer and FT-IR spectroscopy, X-ray diffraction, and conductivity measurements. The valence state and coordination environment of the iron ions change dramatically when the nitrosyl ligand is eliminated by heat-treatment under vacuum at 200 °C. The dark blue product obtained by heat-treatment under vacuum at 250 °C is characteristic of the mixed-valence state in Prussian blue analogues. The electrical conductivity of the dark blue product is higher by a factor o f 103 than that o f the starting material because of the mixed-valence state between Fe(III)[Fe(II)(CN)5] and Fe(II)[Fe(III)(CN)5]. Heat-treatment under vacuum at 350°C yields a new product Fe(II)[Fe(II)(CN)4] the crystal structure of which is different from that of the starting material. The electrical conductivity of the decomposition product obtained at 350 °C is about 105 times higher than that of the starting material.

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“…Such coordination features are supported by X-ray diffraction, thermogravimetric analysis, and Mo ¨ssbauer spectroscopy. [7][8][9][10] Magnetization measurements were performed with a superconducting quantum interference device (SQUID) magnetometer. The effective magnetic moment µ eff at 300 K was 2.94 µ B per formula unit of Ni[Fe(CN) 5 NO]‚5.3H 2 O, indicating that S Ni ) 1 and S Fe ) 0.…”

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“…In this compound, each Fe II ion is coordinated to the carbon ends of five CN ligands plus one nitrosyl group, and each Ni II ion is coordinated to the nitrogen ends of the CN ligands or to water molecules (Figure ). Such coordination features are supported by X-ray diffraction, thermogravimetric analysis, and Mössbauer spectroscopy. − Magnetization measurements were performed with a superconducting quantum interference device (SQUID) magnetometer. The effective magnetic moment μ eff at 300 K was 2.94 μ B per formula unit of Ni[Fe(CN) 5 NO]·5.3H 2 O, indicating that S Ni = 1 and S Fe = 0.…”

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Molecular-Level Design of a Photoinduced Magnetic Spin Coupling System: Nickel Nitroprusside

Sato

Iyoda

et al. 1996

J. Phys. Chem.

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Rational design of a magnetic material (nickel nitroprusside) at the molecular level allowed switching of a spin coupling by means of photoinduced metal to ligand charge transfer (MLCT). Before irradiation, spins on Ni 2+ are in a disordered state. An illumination at 375 nm induces a MLCT from Fe to NO and forms new spins on Fe and NO. The newly appearing spin on Fe orders the spins on the nearest Ni 2+ ions around Fe. In other words, one MLCT aligns five spin sources resulting in the formation of magnetic clusters with S ) 5. Furthermore, such a photoinduced spin ordering can be rerandomized by thermal treatment.One of the remaining, underlying challenges in molecularscale devices is to develop ways to establish switchable communication links between different components and to the outside world. 1,2 Much of the effort in this field has been devoted to electronic communication, most often utilizing longrange electron transfer via π-conjugated systems. 3-5 Here we introduce another potentially valuable approach to molecularlevel communications, which involves tuning the spin coupling via metal to ligand charge transfer (MLCT). The prototype system which we have used is nickel nitroprusside, Ni[Fe-(CN) 5 NO]‚5.3H 2 O (Figure 1). In this compound, randomly aligned neighboring Ni II spins can be ordered through metal (Fe II ) to ligand (NO) charge transfer via light absorption and form spin clusters. The ordered spins can then be rerandomized via thermal treatment. This strategy may also provide the basis for a wholly new approach to the fabrication of optically actuated molecular magnets, which has been identified as an important target of research in molecular magnetic materials. 6Prussian blue analogs are composed of two components, a cyanometalate and an outer cation. These compounds have a three-dimensional network structure. Every outer cation in the network can be coordinated by the nitrogen ends of up to six CN ligands. With such materials, it is possible to design the two components separately. In the present work, the pentacy- † The University of Tokyo.

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On the structure and Mössbauer spectra of ferrous nitroprusside

Cited by 14 publications

References 11 publications

Crystal structures of cubic nitroprussides: M[Fe(CN)₅NO]·xH₂O(M=Fe, Co, Ni). Obtaining structural information from the background

Crystal structures of cubic nitroprussides: M[Fe(CN)₅NO]·xH₂O(M=Fe, Co, Ni). Obtaining structural information from the background

Thermal Decomposition of Prussian Blue Analogues of the Type Fe[Fe(CN)₅NO]

Molecular-Level Design of a Photoinduced Magnetic Spin Coupling System: Nickel Nitroprusside

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On the structure and Mössbauer spectra of ferrous nitroprusside

Cited by 14 publications

References 11 publications

Crystal structures of cubic nitroprussides: M[Fe(CN)5NO]·xH2O(M=Fe, Co, Ni). Obtaining structural information from the background

Crystal structures of cubic nitroprussides: M[Fe(CN)5NO]·xH2O(M=Fe, Co, Ni). Obtaining structural information from the background

Thermal Decomposition of Prussian Blue Analogues of the Type Fe[Fe(CN)5NO]

Molecular-Level Design of a Photoinduced Magnetic Spin Coupling System: Nickel Nitroprusside

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Crystal structures of cubic nitroprussides: M[Fe(CN)₅NO]·xH₂O(M=Fe, Co, Ni). Obtaining structural information from the background

Crystal structures of cubic nitroprussides: M[Fe(CN)₅NO]·xH₂O(M=Fe, Co, Ni). Obtaining structural information from the background

Thermal Decomposition of Prussian Blue Analogues of the Type Fe[Fe(CN)₅NO]