Synthesis, Molecular Structure, and Physical Properties of the Complexes [{PhB(pz)2(CH2SMe)}2M] (M = MnII, FeII; pz = pyrazol‐1‐yl) Containing a Novel [N,N,S]‐Heteroscorpionate Ligand

Reus, Christian; Ruth, Kai; Tüllmann, Sandor; Bolte, Michael; Lerner, Hans‐Wolfram; Weber, Birgit; Holthausen, Max C.

doi:10.1002/ejic.201000552

Cited by 9 publications

(10 citation statements)

References 69 publications

(72 reference statements)

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“…The average Fe-N bond length of 1.990 Å and Fe-S bond length of 2.264 Å in C1 (@173 K) are in accordance with those reported in literature and account for an iron(II) ion in the [LS] state [23][24][25][26][27][28][29]. Figure S7 shows the crystal structure/asymmetric unit of C1 (@173 K).…”

Section: Crystal Structuressupporting

confidence: 85%

First Cobalt(II) Spin Crossover Compound with N4S2-Donorset

et al. 2020

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Herein we report the synthesis and characterization of a novel bis-tridentate 1,3,4-thiadiazole ligand (L = 2,5-bis[(2-pyridylmethyl)thio]methyl-1,3,4-thiadiazole). Two new mononuclear complexes of the type [MII(L)2](ClO4)2 (with M = FeII (C1) and CoII (C2)) have been synthesized, containing the new ligand (L). In both complexes the metal centers are coordinated by an N4S2-donorset and each of the two ligands is donating to the metal ion with just one of the tridentate pockets. The iron(II) complex (C1) is in the low spin [LS] state below room temperature and shows an increase in the magnetic moment only above 300 K. In contrast, the cobalt(II) complex (C2) shows a gradual spin crossover (SCO) with T1/2 = 175 K. To our knowledge, this is the first cobalt(II) SCO complex with an N4S2-coordination.

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Section: Crystal Structuressupporting

confidence: 85%

First Cobalt(II) Spin Crossover Compound with N4S2-Donorset

et al. 2020

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“…Similarly, in toluene solution it undergoes only partial SCO, as monitored by NMR (203− 298 K) and by UV−vis (283−343 K) spectroscopy. 30 To summarize, five of these six examples of structurally characterized, SCO-active N 4 S 2 -coordinated iron(II) complexes are mononuclear and one is a 1D polymer. All six feature thioether S donors.…”

Section: ■ Introductionmentioning

confidence: 97%

“…Prior to those reports, Britovsek and co-workers reported that the closely related N 4 S 2 -coordinated iron(II) complexes [Fe II ( bpte )(MeCN) 2 ] and [Fe II ( bptPh )(MeCN) 2 ] undergo a gradual, almost complete SCO below room temperature in acetonitrile solution . Finally, the N 4 S 2 -coordinated iron(II) complexes [Fe II ( [9]aneN 2 S ) 2 ][ClO 4 ] 2 and {[ PhB(pz) 2 (CH 2 SMe) ] 2 Fe II }, by Gahan and co-workers and by Weber, Holthausen, Wagner, and co-workers, respectively, were both reported to undergo gradual, incomplete SCO. The former complex, [Fe II ( [9]aneN 2 S ) 2 ][ClO 4 ] 2 , transitions between LS in the 4–150 K range and approximately 30% HS at 300 K (see Supporting Information) in the solid state and also shows temperature-dependent magnetic susceptibility in solution .…”

Section: Introductionmentioning

confidence: 99%

Spin Crossover in Dinuclear N₄S₂ Iron(II) Thioether–Triazole Complexes: Access to [HS-HS], [HS-LS], and [LS-LS] States

et al. 2016

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Access to a new family of thioether-linked PSRT ligands, 4-substituted-3,5-bis{[(2-pyridylmethyl)sulfanyl]methyl}-4H-1,2,4-triazoles (analogues of the previously studied amino-linked PMRT ligands), has been established. Four such ligands have been prepared, PSPhT, PS(i)BuT, PS(t-Bu)PhT, and PS(Me)PhT, with R = Ph, (i)Bu, (t-Bu)Ph, and (Me)Ph, respectively. Three dinuclear colorless to pale green iron(II) complexes, [Fe(II)2(PSRT)2](BF4)4·solvent, featuring N4S2 donor sets, were prepared. Single-crystal structure determinations on [Fe(II)2(PSPhT)2](BF4)4·2MeCN·H2O, [Fe(II)2(PSPhT)2](BF4)4·2(1)/2MeCN·(1)/2H2O·THF, [Fe(II)2(PS(Me)PhT)2](BF4)4·2MeCN, and [Fe(II)2(PS(i)BuT)2](BF4)4·4MeCN reveal that all four are stabilized in the [HS-HS] state to 100 K and that both possible binding modes of the bis-terdentate ligands, cis- and trans-axial, are observed. Variable-temperature magnetic susceptibility studies of air-dried crystals (solvatomorphs of the single crystal samples) reveal the first examples of spin crossover (SCO) for a dinuclear iron(II) complex with N4S2 coordination. Specifically, [Fe(II)2(PSPhT)2](BF4)4·2(1)/2H2O undergoes a multistep but complete SCO from [HS-HS] to [LS-LS], whereas [Fe(II)2(PS(Me)PhT)2](BF4)4·1(1)/2MeCN·2H2O exhibits a half-SCO from [HS-HS] to [HS-LS]. In contrast, [Fe(II)2(PS(i)BuT)2](BF4)4·MeCN·H2O remains [HS-HS] down to 50 K. The reflectance spectrum of pale green [Fe(II)2(PSPhT)2](BF4)4·(1)/2CHCl3·2(1)/2H2O (solvatomorph A) reveals a trace of LS character (572 nm band (1)A1g → (1)T1g). Evans' (1)H NMR method and UV-vis spectroscopy studies revealed that on cooling dark green acetonitrile solutions of these complexes from 313 to 233 K, all three undergo SCO centered at or near room temperature. The tendency of the complexes to go LS in solution reflects the electronic impact of R on the σ-donor strength of the PSRT ligand, whereas the opposite trend in stabilization of the LS state is seen in the solid state, where crystal packing effects, of the R group and solvent content, dominate the SCO behavior.

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“…The most widely studied SCO system is iron(II) complexes where the metal centre is surrounded by six nitrogen donors, however there are fewer examples of other metal centres and geometries [13–16] . In addition to the N 6 coordination sphere, recently, it has been demonstrated that N 4 S 2 systems can produce iron(II) SCO‐active complexes, with only a handful of ligands that can provide the right ligand field for SCO to occur, [17–23] Figure 1. All the S‐based ligands contain the same thioether functional group, in combination with amine, pyridine, triazole or pyrazole nitrogen donors, and some of them contain NCE (E=S, Se or BH 3 ) co‐ligands.…”

Section: Introductionmentioning

confidence: 99%

Spin Crossover vs. High‐Spin Iron(II) Complexes in N₄S₂Coordination Sphere Containing Picolyl‐Thioether Ligands and NCE (E=S, Se and BH₃) Co‐Ligands

2021

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To study the effect of the chelate ring size on the magnetic properties of thioether‐based iron(II) metal complexes, two ligands have been envisaged, synthesised and characterised. The two ligands correspond to the bidentate benzylpicolylthioether (PySBn) and tetradentate 2,3‐bis(((2‐pyridylmethyl)thio)methyl)quinoxaline (QuinoxS). Five iron(II) complexes have been synthesised, containing either two bidentate ligands or one tetradentate ligand, and two N‐bond NCE co‐ligands (E=S, Se or BH3): trans‐[FeII(PySBn)2(NCE)2] (1 a–b) and cis‐[FeII(QuinoxS)(NCE)2] (2 a–c), a for E=S, b for E=Se and c for E=BH3. The iron(II) complexes have been characterised by standard techniques, X‐ray crystallography (except for complex 1 a) and VT‐magnetic measurements in the solid state. X‐ray crystallography showed that all the complexes are isolated in the high spin (HS) state, based on the relatively long Fe−L bond lengths, Fe−N>2.0 Å and Fe−S≈2.5–2.6 Å. VT‐magnetic measurements demonstrated that complexes 1 a and 2 a‐c are stabilised in the HS‐state, showing orbital contribution to g and zero field splitting. However, complexes 1 b shows a relatively abrupt, hysteretic, and incomplete at the low‐end spin conversion, with T1/2↓=92, T1/2↑=98 K and ΔT1/2=6 K at 5 K min−1, moreover, the hysteresis loop is scan rate dependent increasing up to 11 K at 10 K min−1. An analysis of structural and electronic parameters has been performed to rationalise the differing magnetic properties of the metal complexes, such as metallacycle size, bond lengths and angles, and cis‐ vs. trans‐coordination mode. A comparison with the literature‐reported spin crossover iron(II) complexes in N4S2 coordination sphere containing NCE co‐ligands has been conducted as well, finding that, as previously reported, the Fe−N−C(E) bond angle is diagnostic for determining the spin lability of the metal complexes, and in addition we have found that the N−C(E) bond length is too useful.

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Synthesis, Molecular Structure, and Physical Properties of the Complexes [{PhB(pz)₂(CH₂SMe)}₂M] (M = Mn^II, Fe^II; pz = pyrazol‐1‐yl) Containing a Novel [N,N,S]‐Heteroscorpionate Ligand

Cited by 9 publications

References 69 publications

First Cobalt(II) Spin Crossover Compound with N4S2-Donorset

First Cobalt(II) Spin Crossover Compound with N4S2-Donorset

Spin Crossover in Dinuclear N₄S₂ Iron(II) Thioether–Triazole Complexes: Access to [HS-HS], [HS-LS], and [LS-LS] States

Spin Crossover vs. High‐Spin Iron(II) Complexes in N₄S₂Coordination Sphere Containing Picolyl‐Thioether Ligands and NCE (E=S, Se and BH₃) Co‐Ligands

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Synthesis, Molecular Structure, and Physical Properties of the Complexes [{PhB(pz)2(CH2SMe)}2M] (M = MnII, FeII; pz = pyrazol‐1‐yl) Containing a Novel [N,N,S]‐Heteroscorpionate Ligand

Cited by 9 publications

References 69 publications

First Cobalt(II) Spin Crossover Compound with N4S2-Donorset

First Cobalt(II) Spin Crossover Compound with N4S2-Donorset

Spin Crossover in Dinuclear N4S2 Iron(II) Thioether–Triazole Complexes: Access to [HS-HS], [HS-LS], and [LS-LS] States

Spin Crossover vs. High‐Spin Iron(II) Complexes in N4S2Coordination Sphere Containing Picolyl‐Thioether Ligands and NCE (E=S, Se and BH3) Co‐Ligands

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Synthesis, Molecular Structure, and Physical Properties of the Complexes [{PhB(pz)₂(CH₂SMe)}₂M] (M = Mn^II, Fe^II; pz = pyrazol‐1‐yl) Containing a Novel [N,N,S]‐Heteroscorpionate Ligand

Spin Crossover in Dinuclear N₄S₂ Iron(II) Thioether–Triazole Complexes: Access to [HS-HS], [HS-LS], and [LS-LS] States

Spin Crossover vs. High‐Spin Iron(II) Complexes in N₄S₂Coordination Sphere Containing Picolyl‐Thioether Ligands and NCE (E=S, Se and BH₃) Co‐Ligands