A room-temperature organometallic magnet based on Prussian blue

Ferlay, Sylvie; Mallah, Talal; Ouahès, R.; Veillet, P.; Verdaguer, Michel

doi:10.1038/378701a0

Cited by 1,533 publications

(868 citation statements)

References 25 publications

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“…A breakthrough in this field has been the synthesis of a room-temperature magnet V[Cr(CN) 6 ] x ‚nH 2 O in 1995. 3 Surprisingly, the room-temperature magnetic behavior of this class of compounds is mainly due to antiferromagnetically coupled t 2g n -t 2g n ′ (n,n′ < 6) pairs of metal ions and a net magnetic moment imposed by mixed-valence, achieved by the control of stoichiometry.…”

Section: Introductionmentioning

confidence: 99%

DFT Studies on the Magnetic Exchange Across the Cyanide Bridge

2006

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Exchange coupling across the cyanide bridge in a series of novel cyanometalate complexes with Cu II -NC-M III (M ) Cr and low-spin Mn,Fe) fragments has been studied using the broken-symmetry DFT approach and an empirical model, which allows us to relate the exchange coupling constant with σ-, π-, and π*-type spin densities of the CN -bridging ligand. Ferromagnetic exchange is found to be dominated by π-delocalization via the CN -π pathway, whereas spin polarization with participation of σ orbitals (in examples, where the d z 2 orbital of M III is empty) and π* orbitals of CN -yields negative spin occupations in these orbitals, and reduces the Cu II -M III exchange coupling constant. When the d z 2 orbital of M III is singly occupied, an additional positive spin density appears in the σ(CN) orbital and leads to an increase of the ferromagnetic Cu-NC-M exchange constant. For low-spin [M III (CN) 6 ] 3-complexes, the d z 2 orbital occupancy results in high-spin metastable excited states, and this offers interesting aspects for applications in the area of molecular photomagnetism. The DFT values of the exchange coupling parameters resulting from different occupations of the t 2g orbitals of low-spin (t 2g 5 ) Fe III are used to discuss the effect of spin-orbit coupling on the isotropic and anisotropic exchange coupling in linear Cu-NC-Fe pairs.

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Section: Introductionmentioning

confidence: 99%

DFT Studies on the Magnetic Exchange Across the Cyanide Bridge

2006

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“…10 9,[12][13][14] The calculations on compounds II and III have been performed by employing a minimal active space for the expansion of the zeroth-order CASSCF wave function. It comprises the five 4d molybdenum orbitals among which the three valence electrons are distributed: CAS (3,5). For the dinuclear complex I, two different complete active spaces have been used as a starting point for the CASPT2 calculations.…”

Section: Computational Detailsmentioning

confidence: 99%

“…First successes in this respect were obtained for the chromovanadium Prussian blue analogues. [2][3][4][5] Later studies demonstrated that the replacement of a first-row transition metal in this kind of compound for a second-row transition metal enhances the magnetic ordering temperature because of the stronger magnetic exchange coupling, which itself is a direct consequence of the more diffuse nature of the high-energy valence 4d orbitals. 6 Recently, several compounds with an octahedral hexacyanomolybdate as a building block have been synthesized.…”

Section: Introductionmentioning

confidence: 99%

[Mo₂(CN)₁₁]:^5- A Detailed Description of Ligand-Field Spectra and Magnetic Properties by First-Principles Calculations

et al. 2005

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An ab initio multiconfigurational approach has been used to calculate the ligand-field spectrum and magnetic properties of the title cyano-bridged dinuclear molybdenum complex. The rather large magnetic coupling parameter J for a single cyano bridge, as derived experimentally for this complex by susceptibility measurements, is confirmed to a high degree of accuracy by our CASPT2 calculations. Its electronic structure is rationalized in terms of spin-spin coupling between the two constituent hexacyano-monomolybdate complexes. An in-depth analysis on the basis of Anderson's kinetic exchange theory provides a qualitative picture of the calculated CASSCF antiferromagnetic ground-state eigenvector in the Mo dimer. Dynamic electron correlations as incorporated into our first-principles calculations by means of the CASPT2 method are essential to obtain quantitative agreement between theory and experiment.

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“…10 Prussian blue (PB) is known as an artificial enzyme peroxidase with porous frameworks, which can efficiently reduce H 2 O 2 at extremely rapid catalytic rates with low overpotentials. 11 For example, molecularly imprinted PB films 12 and PB/carbon nanotubes 13 have been used for biosensing because their low overpotentials can exclude interferences from coexisting substances, such as ascorbic acid (AA), uric acid and glucose. However, previous work predominantly used PB nanocrystals that had been post-modified on flat substrates, and thus, only a limited number of crystal faces were exposed to electrolytes, which resulted in lower electrochemical responses.…”

Section: Introductionmentioning

confidence: 99%

Bio-inspired porous antenna-like nanocube/nanowire heterostructure as ultra-sensitive cellular interfaces

Kong

Tang

et al. 2014

NPG Asia Mater

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In this study, an unconventional antenna-like heterostructure comprised of arrays of nanoporous Prussian blue (PB) nanocube heads/TiO 2 nanowire (NW) arms (PB-TiO 2 ) is developed for efficient three-dimensional interfacial sensing of small molecules and cellular activities. Inspired by insect tentacles, which are comprised of both target recognition and signal transduction units, one-dimensional TiO 2 NW arrays are grown, followed by selective growth of nanoporous PB nanocubes on the tips of the NW arrays. Due to their high selectivity and bioaffinity toward cells, long biostability under a cell culture adhesion condition (up to 108 h) is obtained, and with its inherent bio-mimetic enzymatic activity, the obtained nanoporous PB nanocubes (head segment) serve as robust substrates for site-selective cell adhesion and culture, which allows for sensitive detection of H 2 O 2 . Simultaneously, the single-crystalline TiO 2 NWs (arm segment) provide efficient charge transport for electrode substrates. Compared with PB-functionalized planar electrochemical interfaces, the PB-TiO 2 antenna NW biointerfaces exhibit a substantial enhancement in electrocatalytic activity and sensitivity for H 2 O 2 , which includes a low detection limit (B20 nM), broad detection range (10 À8 to 10 À5 M), short response time (B5 s) and long-term biocatalytic activity (up to 6 months). The direct cultivation of HeLa cells is demonstrated on the PB-TiO 2 antenna NW arrays, which are capable of sensitive electrochemical recording of cellular activity in real time, where the results suggest the uniqueness of the biomimic PB-TiO 2 antenna NWs for efficient cellular interfacing and molecular recognition.

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A room-temperature organometallic magnet based on Prussian blue

Cited by 1,533 publications

References 25 publications

DFT Studies on the Magnetic Exchange Across the Cyanide Bridge

DFT Studies on the Magnetic Exchange Across the Cyanide Bridge

[Mo₂(CN)₁₁]:^5- A Detailed Description of Ligand-Field Spectra and Magnetic Properties by First-Principles Calculations

Bio-inspired porous antenna-like nanocube/nanowire heterostructure as ultra-sensitive cellular interfaces

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A room-temperature organometallic magnet based on Prussian blue

Cited by 1,533 publications

References 25 publications

DFT Studies on the Magnetic Exchange Across the Cyanide Bridge

DFT Studies on the Magnetic Exchange Across the Cyanide Bridge

[Mo2(CN)11]:5- A Detailed Description of Ligand-Field Spectra and Magnetic Properties by First-Principles Calculations

Bio-inspired porous antenna-like nanocube/nanowire heterostructure as ultra-sensitive cellular interfaces

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[Mo₂(CN)₁₁]:^5- A Detailed Description of Ligand-Field Spectra and Magnetic Properties by First-Principles Calculations