Thermal- and light-induced spin transition in [Fe(mtz)6](BF4)2: first successful formation of a metastable low-spin state by irradiation with light at low temperatures

Poganiuch, P.; Decurtins, Silvio; Guetlich, P.

doi:10.1021/ja00165a003

Cited by 144 publications

(70 citation statements)

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“…The expression (1) shows that for large n the desired parameter Γ has the order of magnitude of 2RT n . Some features of the HS ↔ LS2 transition under hydrostatic pressure investigated in (2Me-5Et-PyH)[Fe(Th-5Cl-Sa) 2 ], crossover effect itself, incompleteness of transition, and varying density of the LS complexes in the domains of a new phase are of similar character to those observed and discussed previously in some other Fe(III) thiosemicabazonates [16,17,23]. Let us consider the newly discovered phenomena: the existence of the additional pressure induced metastable LS phase and temperature independence of the pressure inducing the LS1 ↔ LS2 transition.…”

Section: Discussionsupporting

confidence: 69%

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EPR Discovery of a New Pressure-Induced Low-Spin Phase in (2Me-5Et-PyH)[Fe(Th-5Cl-Sa)₂]

et al. 2006

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Electron paramagnetic resonance studies of the high-spin (HS) ↔ low--spin (LS) transition in 2-methyl-5-ethyl-pyridine-5-chloro-salicylalthiosemicarbazonatoferrate(III) performed under hydrostatic pressure up to 500 MPa in a temperature range of 80-310 K have revealed two modifications of the low spin complexes: low-pressure (LS1) and high-pressure (LS2) ones. Under atmospheric pressure LS1 appears on cooling and disappears on heating at 220 K. The hydrostatic pressure shifts the transition to higher temperatures. Below 275 K an increase in pressure to 410 MPa results in abrupt changes in the g-factor and width ∆B of the EPR line indicating a transition to a new phase. The pressure-induced transition LS1 ↔ LS2 is almost independent of T up to 275 K, where at a pressure of 420 MPa a triple point is observed. The LS1 ↔ LS2 and HS ↔ LS2 (at T > 260 K) transitions occur with a large hysteresis of about 95 MPa. The process of the spin transition has been shown to begin with the formation of domains of LS complexes in the matrix of HS ones. The response of the domains to external factors has been studied.

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Section: Discussionsupporting

confidence: 69%

“…The compounds with thermal or pressure hysteresis of the spin transition are the most attractive as this phenomenon indicates that the complexes are able to exist in two different electronic states at the same temperature or pressure (bistability phenomenon potentially important for molecular electronics) [17,18].…”

Section: A Lot Of the 3dmentioning

confidence: 99%

EPR Discovery of a New Pressure-Induced Low-Spin Phase in (2Me-5Et-PyH)[Fe(Th-5Cl-Sa)₂]

et al. 2006

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“…It is therefore important to identify and understand the nature of the parameters affecting the stability of the photo-induced state, [5,6] and indeed many different complexes have been studied for the LIESST effect. Of those containing iron(ii), however, the majority use terminal ligands [3,[7][8][9] and are thus only able to form mononuclear complexes. Notable exceptions involve dimers [10,11] and a mixed-metal bridging system with a 2D layered structure.…”

Section: Introductionmentioning

confidence: 99%

“…Iron(ii) spin-crossover compounds have been produced with many different N-coordinating heterocyclic ligands, such as triazoles, [13] tetrazoles [3,[7][8][9]14] and imidazoles. [15] In Abstract: A new series of [m-tris-{1,nbis(tetrazol-1-yl)alkane-N4,N4'}iron(ii)] bis(perchlorate) spin-crossover coordination polymers ([Fe(nditz) 3 ](ClO 4 ) 2 ]; n = 4-9) has been synthesised and characterised.…”

Section: Introductionmentioning

confidence: 99%

Both Spacer Length and Parity Influence the Thermal and Light‐Induced Properties of Iron(II) α,ω‐Bis(tetrazole‐1‐yl)alkane Coordination Polymers

Absmeier

Bartel

Carbonera

et al. 2006

Chemistry A European J

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A new series of [mu-tris-{1,n-bis(tetrazol-1-yl)alkane-N4,N4'}iron(II)] bis(perchlorate) spin-crossover coordination polymers ([Fe(nditz)3](ClO4)2]; n = 4-9) has been synthesised and characterised. The ditetrazole bridging ligands provide octahedral symmetry at the iron(II) centres while allowing the distance between iron(II) centres to be varied. These polymers have therefore been investigated to determine the effects of spacer length on their thermal and light-induced spin-transition behaviour. An increase in the number of carbon atoms in the spacer (n) raises the thermal spin-crossover temperature, while decreasing the stability of the light-induced metastable state generated through the light-induced excited spin state trapping (LIESST) effect by irradiating the sample at 530 nm. Remarkably, however, the parity of the spacer also has an effect, enabling the series of complexes to be divided into two sub-series depending on whether the bridging ligand possesses an even or an odd number of carbon atoms. An explanation at the molecular level using the single configurational coordinate (SCC) model is presented.

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“…The alkyltetrazole ligands were prepared as described by Franke et al [6] and the complexes themselves were prepared by the method of Poganiuch et al [7]. The crude (polycrystalline) products were recrystallized from nitromethane to obtain single crystals.…”

Section: Methodsmentioning

confidence: 99%

Ortho-Positronium Lifetime As a Detector of Spin-Crossover

et al. 1999

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Positron lifetime parameters were measured for the spin-crossover complexes [Fe(R-1H-tetrazole)6](BF 4 ) 2 (R = 1-ethyl, 1-n-propyl) and for the diamagnetic [Zn(1-n-propyl-1H-tetrazole)6](BF 4 )2. Positronium forms with significant intensity in the studied compounds. The ortho-para conversion of ortho-positronium was used to follow the spin-crossover. Changes of the dynamic structure were found in the propyltetrazole complex between 150 K and 90 K.

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Thermal- and light-induced spin transition in [Fe(mtz)6](BF4)2: first successful formation of a metastable low-spin state by irradiation with light at low temperatures

Cited by 144 publications

References 0 publications

EPR Discovery of a New Pressure-Induced Low-Spin Phase in (2Me-5Et-PyH)[Fe(Th-5Cl-Sa)₂]

EPR Discovery of a New Pressure-Induced Low-Spin Phase in (2Me-5Et-PyH)[Fe(Th-5Cl-Sa)₂]

Both Spacer Length and Parity Influence the Thermal and Light‐Induced Properties of Iron(II) α,ω‐Bis(tetrazole‐1‐yl)alkane Coordination Polymers

Ortho-Positronium Lifetime As a Detector of Spin-Crossover

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Thermal- and light-induced spin transition in [Fe(mtz)6](BF4)2: first successful formation of a metastable low-spin state by irradiation with light at low temperatures

Cited by 144 publications

References 0 publications

EPR Discovery of a New Pressure-Induced Low-Spin Phase in (2Me-5Et-PyH)[Fe(Th-5Cl-Sa)2]

EPR Discovery of a New Pressure-Induced Low-Spin Phase in (2Me-5Et-PyH)[Fe(Th-5Cl-Sa)2]

Both Spacer Length and Parity Influence the Thermal and Light‐Induced Properties of Iron(II) α,ω‐Bis(tetrazole‐1‐yl)alkane Coordination Polymers

Ortho-Positronium Lifetime As a Detector of Spin-Crossover

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EPR Discovery of a New Pressure-Induced Low-Spin Phase in (2Me-5Et-PyH)[Fe(Th-5Cl-Sa)₂]

EPR Discovery of a New Pressure-Induced Low-Spin Phase in (2Me-5Et-PyH)[Fe(Th-5Cl-Sa)₂]