Substituent‐Influenced Spin Cross­over in Fe<sup>III</sup> Quinolylsalicylaldimin­ates

Sertphon, Darunee; Harding, David J.; Harding, Phimphaka; Murray, Keith S.; Moubaraki, Boujemaa; Adams, Harry; Alkaş, Adil; Telfer, Shane G.

doi:10.1002/ejic.201501188

Cited by 14 publications

(15 citation statements)

References 39 publications

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“…These complexes, although not isolated in the solid state, represent interesting model complexes of the potential spin crossover (SCO) behavior. In order to model the possible electron configurations, both the HS ( S = 5/2, sixtuplet) and LS ( S = 1/2, doublet) configurations were modeled for the three Fe III complexes. The optimized structures of complexes 1c + –3c + show the central ion in a distorted octahedral coordination achieved by the two N1 and N2 atoms and by the O atoms (Figure S8 for 1c + in the HS state).…”

Section: Resultsmentioning

confidence: 99%

Structural Diversity in a New Series of Halogenated Quinolyl Salicylaldimides-Based Fe^III Complexes Showing Solid-State Halogen-Bonding/Halogen···Halogen Interactions

Sahadevan

Cadoni

Monni

et al. 2018

Crystal Growth & Design

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A new series of tridentate N-8-quinolyl-salicylaldimine ligands, Hqsal-5,7-X 2 [X = Cl(1), Br(2), I(3)], halosubstituted at the 5,7 position of the aminoquinoline moiety and their corresponding complexes with Fe III were synthesized and formulated as [Fe(qsal-5,7-X 2)(NCS)(MeO)] 2 •solv. (X = Cl (1a), Br (2a), I (3a, solv = 1 / 2 MeOH), [Fe 4 (qsal-5,7-X 2) 4 (NCS) 2-(MeO) 2 ]•solv. (X = Br (2b), I (3b; solv = 4CH 2 Cl 2)) by singlecrystal X-ray diffraction analysis. 1a and 2a are isostructural dimers where each Fe III metal ion, showing a distorted octahedral environment, is bound by a N,N,O tridentate (qsal-5,7-X 2) − (X = Cl and Br) ligand, a N-coordinated SCN − anion, and a bridging methanolate anion. 2b and 3b are centrosymmetric tetramers where each Fe III is bound by three nitrogen atoms and three oxygen atoms derived from a tridentate (qsal-5,7-X 2) − (X = Br and I), a SCN − , a bridging methanolate anion, and a bridging μ 2oxy moiety. In 3b, the iodine atoms dominate the packing interactions through the establishment of a halogen-bonding network. The magnetic behavior of 1a−3a dimers and 2b−3b tetramers indicate the presence of strong antiferromagnetic interactions between Fe III centers (S = 5/2), mediated by the alkoxy bridges. Experimental data can be modeled with an isotropic Hamiltonian, H = −2J(S 1 • S 2) for dimers (J = −15 cm −1) and H = −2J(S 2 • S 3) − 2J′(S 1 • S 2 + S 3 • S 4), for tetramers (J = −24 cm −1 , J′ = −11 cm −1). The magnetic behavior of 1a−3a dimers indicates the presence of strong antiferromagnetic interactions between Fe III centers (S = 5/2), mediated by the alkoxy bridges. 2b and 3b show the same magnetic behavior since they contains analogous bridges between paramagnetic centers, but for a linear tetramer. Density functional theory (DFT) calculations, based on hybrid functional mPW1PW paralleled by the Def2SVP all-electron split-valence basis sets, support the experimental results, showing that monomers could possibly show a spin crossover (SCO) behavior, even though the formation of complexes with an even number of metal ions results in the strong antiferromagnetic interactions. Accordingly, broken symmetry DFT calculations carried out on 1a clearly show that the antiferromagnetic coupling of the two HS Fe III centers results in the lowest energy electron configuration of the complex.

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Section: Resultsmentioning

confidence: 99%

Structural Diversity in a New Series of Halogenated Quinolyl Salicylaldimides-Based Fe^III Complexes Showing Solid-State Halogen-Bonding/Halogen···Halogen Interactions

Sahadevan

Cadoni

Monni

et al. 2018

Crystal Growth & Design

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“…In addition to the halogen-substituted Hqsal ligands, the MeO-substituted Hqsal ligands have also been explored a lot. Besides the LS complex [Fe(qsal-3-OMe) 2 ]PF 6 · n H 2 O, related complexes [Fe(qsal-5-OMe) 2 ]Y·sol (Y = Cl – , NCS – , BF 4 – , PF 6 – , BPh 4 – ) with the MeO– group substituted in the 5-position all exhibit SCO, in three cases with hysteresis, while complexes [Fe(qsal-4-OMe) 2 ]Y (Y = ClO 4 – , NO 3 – , PF 6 – , OTf – ) with substituent in the 4-position are mostly HS complexes with the exception of the OTf – derivative exhibiting a gradual 25% SCO . Magneto-structural analysis revealed that the distortion of the qsal-4-OMe – ligand and intermolecular C–H···O interactions seem to be responsible for the loss of SCO .…”

Section: Introductionmentioning

confidence: 99%

Anion Modified Spin Crossover in [Fe(qsal-4-F)]⁺ Complexes with a 4-Position Substituted Qsal Ligand

et al. 2022

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Four iron(III) complexes, [Fe(qsal-4-F)2]Y·sol (Hqsal-4-F = 4-fluoro-N-(8-quinolyl)salicylaldimine; Y = NO3 –, sol = 0.91MeOH·0.57H2O (1NO3 ); Y = PF6 – (2PF6 ); Y = BF4 – (3BF4 ); Y = OTf–, sol =1.5MeOH (4OTf )), with a new 4-position substituted qsal type ligand Hqsal-4-F have been synthesized and structurally and magnetically characterized. Complexes 1NO3 –3BF4 consist of 1D chains formed by the [Fe(qsal-4-F)2]+ cations connected by π–π and C–H···O interactions, which are further linked by more weak interactions to form 2D layers and 3D networks. On the other hand, complex 4OTf has a structure of nearly isolated 1D column where the [Fe(qsal-4-F)2]+ cations are connected by π–π, C–H···π, and C–F···π interactions. Magnetic studies revealed the occurrence of two-step symmetry-breaking SCO in 1NO3 and two-step gradual SCO in 2PF6 . Complex 3BF4 undergoes a gradual SCO, whereas 4OTf remains almost high-spin. The smaller anions tend to stabilize the low-spin state, while larger anions tend to stabilize the high-spin state. In addition, the intermediate spin state of 1NO3 could be thermally trapped by quenching from the high temperature, thereby kinetically suppressing the spin transition to the full low-spin state. This work represents a good example that the position of the substituent and the anions plays critical roles in the preparation of SCO materials with tunable properties.

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“…Here we apply this approach to the Fe(III) SCO active metal complex [Fe(qsal-5-OMe) 2 ]NCS ,− and show that this material can be tuned to produce three different spin-switching temperatures, leading to solvatomorphic triple hysteresis and six different stable magnetic states resulting from a single-crystal-to-single-crystal transformation.…”

Section: Introductionmentioning

confidence: 99%

Three-Way Switchable Single-Crystal-to-Single-Crystal Solvatomorphic Spin Crossover in a Molecular Cocrystal

et al. 2020

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The Fe(III) spin-switching complexes [Fe(qsal-5-Y)2]X (where Y = F, Cl, Br, I or OMe; X = NCS–, Cl–, OTf–, NO3 –, BF4 –, PF6 –, or BPh4 –) display a variety of thermal spin transition profiles, including abrupt, stepped, and hysteretic, with potential applications as temperature- or gas-dependent switches or memory/storage devices. Here, the complex [Fe(qsal-OMe)2]NCS is encased within discrete anionic supramolecular motifs in cocrystalline [Fe(qsal-OMe)2][(1,3,5-triiodotrifluorobenzene)(NCS)]·MeOH/H2O (1·IFB·solvent). The MeOH and H2O solvate within these robust crystals can be reversibly exchanged, giving an artificial triple hysteresis, with six different stable magnetic states and a ΔT 1/2 of 95 K (MeOH versus H2O solvatomorphs), which represent the workings of a stimulated logic gate that can be reset with heat or vacuum. Variable-temperature single-crystal X-ray diffraction (VT-SCXRD) elucidated the entire spin transition profile of the parent complex [Fe(qsal-OMe)2](NCS)·MeCN (1·MeCN) and the anionic supramolecular framework-like adducts [Fe(qsal-OMe)2][(1,3,5-triiodotrifluorobenzene)(NCS)] (1·IFB), [Fe(qsal-OMe)2][(1,3,5-triiodotrifluorobenzene)(NCS)]·MeOH (1·IFB·MeOH) and [Fe(qsal-OMe)2][(1,3,5-triiodotrifluorobenzene)(NCS)]·H2O (1·IFB·H 2 O), with full structures collected every 5 or 10 K (total of 202 individual structures) over a temperature range of 100–450 K. The reversible solvent exchange and magnetic changes suggest that crystalline 1·IFB may be used as a specialized molecular magnetic sensor for MeOH and H2O.

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Substituent‐Influenced Spin Crossover in Fe^III Quinolylsalicylaldiminates

Cited by 14 publications

References 39 publications

Structural Diversity in a New Series of Halogenated Quinolyl Salicylaldimides-Based Fe^III Complexes Showing Solid-State Halogen-Bonding/Halogen···Halogen Interactions

Structural Diversity in a New Series of Halogenated Quinolyl Salicylaldimides-Based Fe^III Complexes Showing Solid-State Halogen-Bonding/Halogen···Halogen Interactions

Anion Modified Spin Crossover in [Fe(qsal-4-F)]⁺ Complexes with a 4-Position Substituted Qsal Ligand

Three-Way Switchable Single-Crystal-to-Single-Crystal Solvatomorphic Spin Crossover in a Molecular Cocrystal

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Substituent‐Influenced Spin Cross­over in FeIII Quinolylsalicylaldimin­ates

Cited by 14 publications

References 39 publications

Structural Diversity in a New Series of Halogenated Quinolyl Salicylaldimides-Based FeIII Complexes Showing Solid-State Halogen-Bonding/Halogen···Halogen Interactions

Structural Diversity in a New Series of Halogenated Quinolyl Salicylaldimides-Based FeIII Complexes Showing Solid-State Halogen-Bonding/Halogen···Halogen Interactions

Anion Modified Spin Crossover in [Fe(qsal-4-F)]+ Complexes with a 4-Position Substituted Qsal Ligand

Three-Way Switchable Single-Crystal-to-Single-Crystal Solvatomorphic Spin Crossover in a Molecular Cocrystal

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Substituent‐Influenced Spin Crossover in Fe^III Quinolylsalicylaldiminates

Structural Diversity in a New Series of Halogenated Quinolyl Salicylaldimides-Based Fe^III Complexes Showing Solid-State Halogen-Bonding/Halogen···Halogen Interactions

Structural Diversity in a New Series of Halogenated Quinolyl Salicylaldimides-Based Fe^III Complexes Showing Solid-State Halogen-Bonding/Halogen···Halogen Interactions

Anion Modified Spin Crossover in [Fe(qsal-4-F)]⁺ Complexes with a 4-Position Substituted Qsal Ligand