Bulk spin-crossover in the complex [FeL(NCS)<sub>2</sub>] of a tris(pyridyl)ethane-derived N<sub>4</sub>-ligand—a temperature-dependent crystallographic study

Wiedemann, Dennis; Grohmann, Andreas

doi:10.1039/c3dt53070a

Cited by 8 publications

(9 citation statements)

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“…The best fit was obtained for Δ H = 19.1 kJ · mol –1 , Δ S = 77 J · mol –1 · K –1 , ε HS = 850 M –1 · cm –1 and ε LS = 4560 M –1 · cm –1 (red line in Figure ). The obtained Δ H and Δ S values are in the typical range for iron(II) SCO systems in solution , , . Using the relation Δ H = T ½ · Δ S , the SCO temperature can be determined to T ½ = 248 K in EtCN.…”

Section: Resultsmentioning

confidence: 85%

“…The obtained ΔH and ΔS values are in the typical range for iron(II) SCO systems in solution. [22,23,29] Using the relation ΔH = T ½ ·ΔS, the SCO temperature can be determined to T ½ = 248 K in EtCN. With the respective ε HS and ε LS values the mole fraction of molecules in the high-spin state at a given temperature can be calculated according to Equation (1) (Figure 7, bottom).…”

Section: Articlementioning

confidence: 99%

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Spin State Variations and Spin‐Crossover in Diiron(II) Complexes of Bis(pentadentate) Pyrazolate‐Based Ligands

Schober

Demeshko

Meyer

2018

Zeitschrift anorg allge chemie

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Compartmental pyrazolato‐bridged ligands [LPy]− and [LIm]−, each providing two {N5} binding sites but differing in the terminal N‐donors (pyridine vs. imidazole), were used to prepare a set of diferrous complexes; the ligand HLIm is new and its synthesis is reported. Complexes [LPyFe2(MeCN)2](OTf)3, (1OTf), [LPyFe2(MeCN)2](BF4)3 (1BF4), [LImFe{Fe(MeCN)}](OTf)3 (2OTf), and [LImFe{Fe(MeCN)}](BF4)3 (2BF4) were characterized by single‐crystal X‐ray diffraction, revealing a MeCN coligand at both (1OTf, 1BF4) or at only one (2OTf, 2BF4) of the two accessible Fe coordination sites that are directed into the bimetallic cleft. Magnetic measurements (SQUID) and 57Fe Mößbauer spectroscopy indicate low‐spin states for the six‐coordinate FeII ions in 1OTf and 1BF4 that are based on [LPy]−, but two high‐spin FeII ions in 2BF4 that is based on [LIm]−, in agreement with structural data. Complex 2OTf shows abrupt spin‐crossover (SCO) from a mixed high‐spin/low‐spin to an all high‐spin state at T½ = 264 K, which appears to be correlated with the Fe–N≡C(Me) bonding angle. SCO, though gradual, is observed for 2OTf also in solution (T½ = 273 K in MeCN, 248 K in EtCN), which was studied by Mössbauer spectroscopy of frozen solution samples, variable temperature UV/Vis spectroscopy and SQUID magnetometry; the latter methods consistently gave thermodynamic parameters ΔH = 24.2 kJ·mol–1, ΔS = 89 J·mol–1·K–1 for the SCO of 2OTf in MeCN, and ΔH = 19.1 kJ·mol–1, ΔS = 77 J·mol–1·K–1 in EtCN.

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Section: Resultsmentioning

confidence: 85%

Section: Articlementioning

confidence: 99%

Spin State Variations and Spin‐Crossover in Diiron(II) Complexes of Bis(pentadentate) Pyrazolate‐Based Ligands

Schober

Demeshko

Meyer

2018

Zeitschrift anorg allge chemie

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“…b) Estimation using a spin‐only model: μ eff ≈ 2[ S ( S + 1)] ½ . c) Data have been published3b,5 before and are included for comparison.…”

Section: Resultsmentioning

confidence: 99%

“…The bis(thiocyanato) complex [Fe II L(NCS) 2 ] ( 2d ), when deposited as a submonolayer on graphite, undergoes thermally induced, fully reversible, gradual one‐step spin‐crossover (SCO) without hysteresis; it is one of very few compounds known to date, which are capable of such transitions in direct contact with a surface 4. The SCO correlates with structural features in solutions, powders, and crystals of 2d , and comparison with the complexes [Fe II Cl 2 L] ( 2a ) and [Fe III Cl 2 L]PF 6 ( 2b ) elucidated further details 5. Why the transition temperature in 2d is relatively high has, however, remained an open question; also, the coordination chemistry of this ligand with other transition metal ions has been largely unexplored.…”

Section: Introductionmentioning

confidence: 99%

3d‐ and 4d‐Metal(II) Complexes of a Tris(pyridyl)ethane‐Derived N₄ Ligand – A Structural Study and Reactivity Remarks

Wiedemann

Grohmann

2014

Zeitschrift anorg allge chemie

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Dennis Wiedemann, Andreas Grohmann 3d-and 4d-metal(II) complexes of a tris(pyridyl)ethane-derived N-4 ligand -a structural study and reactivity remarks Article, Postprint versionThis version is available at http://dx.doi.org/10.14279/depositonce-5486. This is the peer reviewed version of the following article:Wiedemann, Dennis; Grohmann, Andreas: 3d-and 4d-metal(II) complexes of a tris(pyridyl)ethane-derived N-4 ligand -a structural study and reactivity remarks. -Zeitschrift für anorganische und allgemeine Chemie. -ISSN: 1521-3749 (online), 0044-2313 (print). -640 (2014), 8-9 -pp. 1632-1640. -DOI: 10.1002 which has been published in final form at https://dx.doi.org/10.1002/zaac.201400047. This article may be used for noncommercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. Terms of UseCopyright applies. A non-exclusive, non-transferable and limited right to use is granted. This document is intended solely for personal, non-commercial use.

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“…Attemptstos ynthesize 1 and 2 with non-coordinating solvents such as CH 2 Cl 2 and CHCl 3 yielded bis-complexes of the type [(L) 2 Fe](SO 3 CF 3 ) 2 .T his is not surprising since the formation of bis-complexesb ys tructurally similar ligandsh as been reported for Cu II ,F e II ,R u II ,C o II ,N i II ,Z n II and Mn II complexes, [12] and the formationo fb is-complexes was only avoided in af ew cases by the substitution at the orthopositiono ft he pyridyl arms of the ligand. [13] The solutionm agnetic susceptibilities of 1 and 2 (Evans method) are m eff = 5.1-5.3 m B ,t hat is, close to the spin-only value for ah igh-spin Fe II center. Thati s, in solutiont he Fe II centers have high-spin electronic configuration as in the enzyme.…”

Section: Syntheses and Characterizationmentioning

confidence: 61%

A Structural and Functional Model for the Tris‐Histidine Motif in Cysteine Dioxygenase

Anandababu

Ramasubramanian

Wadepohl

et al. 2019

Chemistry A European J

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The iron(II) complexes [Fe(L)(MeCN) 3 ](SO 3 CF 3 ) 2 (L are two derivativeso ft ris(2-pyridyl)-based ligands) have been synthesized as modelsf or cysteined ioxygenase (CDO). The molecular structure of one of the complexesexhibits octahedral coordination geometry and the FeÀN py bond lengths [1.953(4)-1.972(4) ]a re similar to those in the Cysbound Fe II -CDO;F e ÀN His :1 .893-2.199 .T he iron(II) centers of the model complexes exhibit relatively highF e III/II redox potentials (E 1/2 = 0.988-1.380V vs. ferrocene/ferrocenium electrode, Fc/Fc + ), within the range for O 2 activation and typical for the corresponding nonheme iron enzymes.T he reaction of in situ generated [Fe(L)(MeCN)(SPh)] + with excess O 2 in acetonitrile (MeCN) yields selectively the doubly oxygenated phenylsulfinic acid product. Isotopic labeling studies using 18 O 2 confirm the incorporation of both oxygen atomso fO 2 into the product. Kinetic and preliminary DFT studies revealthe involvement of an Fe III peroxido intermediate with ar hombic S = 1 = 2 Fe III center( 687-696 nm; g % 2.46-2.48, 2.13-2.15, 1.92-1.94), similar to the spectroscopic signature of the low-spin Cys-bound Fe III CDO (650 nm, g % 2.47, 2.29, 1.90). The proposed Fe III peroxido intermediates have been trapped, and the OÀOs tretching frequencies are in the expected range (approximately 920 and 820 cm À1 for the alkyl-and hydroperoxido species, respectively). The model complexesh ave as tructure similart ot hat of the enzyme and structural aspects as well as the reactivity are discussed.Scheme1.Chemical structures of the CDO active site and the CDO-Cys adduct.

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Bulk spin-crossover in the complex [FeL(NCS)₂] of a tris(pyridyl)ethane-derived N₄-ligand—a temperature-dependent crystallographic study

Cited by 8 publications

References 34 publications

Spin State Variations and Spin‐Crossover in Diiron(II) Complexes of Bis(pentadentate) Pyrazolate‐Based Ligands

Spin State Variations and Spin‐Crossover in Diiron(II) Complexes of Bis(pentadentate) Pyrazolate‐Based Ligands

3d‐ and 4d‐Metal(II) Complexes of a Tris(pyridyl)ethane‐Derived N₄ Ligand – A Structural Study and Reactivity Remarks

A Structural and Functional Model for the Tris‐Histidine Motif in Cysteine Dioxygenase

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Bulk spin-crossover in the complex [FeL(NCS)2] of a tris(pyridyl)ethane-derived N4-ligand—a temperature-dependent crystallographic study

Cited by 8 publications

References 34 publications

Spin State Variations and Spin‐Crossover in Diiron(II) Complexes of Bis(pentadentate) Pyrazolate‐Based Ligands

Spin State Variations and Spin‐Crossover in Diiron(II) Complexes of Bis(pentadentate) Pyrazolate‐Based Ligands

3d‐ and 4d‐Metal(II) Complexes of a Tris(pyridyl)ethane‐­Derived N4 Ligand – A Structural Study and Reactivity ­Remarks

A Structural and Functional Model for the Tris‐Histidine Motif in Cysteine Dioxygenase

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Bulk spin-crossover in the complex [FeL(NCS)₂] of a tris(pyridyl)ethane-derived N₄-ligand—a temperature-dependent crystallographic study

3d‐ and 4d‐Metal(II) Complexes of a Tris(pyridyl)ethane‐Derived N₄ Ligand – A Structural Study and Reactivity Remarks