Structural, magnetic and Mössbauer spectroscopic studies of the [Fe(3-bpp)2](CF3COO)2 complex: role of crystal packing leading to an incomplete Fe(<scp>ii</scp>) high spin ⇋ low spin transition

Sugiyarto, Kristian Handoyo; Onggo, Djulia; Akutsu, Hiroki; Reddy, ‬V. Raghavendra; Sutrisno, Hari; Nakazawa, Yasuhiro; Bhattacharjee, A.

doi:10.1039/d0ce01687j

Cited by 8 publications

(9 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the spectrum of the latter, this is the main species (81%) with an isomer shift of 0.44 mm s –1 along with a quadrupole splitting of 0.43 mm s –1 and a set of two minor signals with isomer shifts of 1.28 and 1.05 mm s –1 and quadrupole splittings with 3.24 and 2.86 mm s –1 . The observed data for the main species and the species observed for the dissolved crystals are in accordance to values reported for low-spin iron(II) species with a {N 6 }-coordination indicating that the bis(acetonitrile) species is dominant in acetonitrile solution. ,− …”

Section: Resultssupporting

confidence: 85%

Triflate vs Acetonitrile: Understanding the Iron(II)-Based Coordination Chemistry of Tri(quinolin-8-yl)amine

et al. 2023

View full text Add to dashboard Cite

In this study, a synthesis route of tri(quinolin-8yl)amine (L), a recent member of the tetradentate tris(2pyridylmethyl)amine (TPA) ligand family, is reported. With the neutral ligand L bound to an iron(II) center in κ 4 mode, two cisoriented coordination sites remain vacant. These can be occupied by coligands such as counterions and solvent molecules. How sensitive this equilibrium can be is most evident if both triflate anions and acetonitrile molecules are available. All three combinations�bis(triflato), bis(acetonitrile), and mixed coligand species�could be characterized by single-crystal X-ray diffraction (SCXRD), which is unique so far for this class of ligand. While at room temperature, the three compounds tend to crystallize concomitantly, the equilibrium can be shifted in favor of the bis(acetonitrile) species by lowering the crystallization temperature. Removed from their mother liquor, the latter is very sensitive to evaporation of the residual solvent, which was observed by powder X-ray diffraction (PXRD) and Mossbauer spectroscopy. The solution behavior of the triflate and acetonitrile species was studied in detail using time-and temperature-resolved UV/vis spectroscopy, Mossbauer spectroscopy of frozen solution, NMR spectroscopy, and magnetic susceptibility measurements. The results indicate a bis(acetonitrile) species in acetonitrile showing a temperature-dependent spin-switching behavior between highand low-spin. In dichloromethane, the results reveal a high-spin bis(triflato) species. In pursuit of understanding the coordination environment equilibria of the [Fe(L)] 2+ complex, a series of compounds with different coligands was prepared and analyzed with SCXRD. The crystal structures indicate that the spin state can be controlled by changing the coordination environment�all of the {N 6 }-coordinated complexes display geometries expected for low-spin species, while any other donor atom in the coligand position induces a shift to the high-spin state. This fundamental study sheds light on the coligand competition of triflate and acetonitrile, and the high number of crystal structures allows further insights into the influence of different coligands on the geometry and spin state of the complexes.

show abstract

Section: Resultssupporting

confidence: 85%

Triflate vs Acetonitrile: Understanding the Iron(II)-Based Coordination Chemistry of Tri(quinolin-8-yl)amine

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Confirmation of the virtually spin-state transition in [Fe(paptH)2] 2+ was clearly demonstrated by measurements of Mössbauer spectroscopy (Sugiyarto et al, 2003;Sugiyarto et al, 2021;Ritter et al, 1978). In this work, the study of Mössbauer spectra for the nitroprusside salt, [Fe(paptH)2][Fe(NO)5NO] .…”

Section: Mössbauer Effectsupporting

confidence: 66%

“…It is clear from Figure 3B that doublet I certainly corresponds to low-spin iron(II) in the nitroprusside anion (Sugiyarto et al, 2003). Doublet II is then due to the iron(II) cationic site; its parameters, quadrupole splitting, EQ = 2.37 mm s -1 , and isomer shift,  is = 1.23 mm s -1 , are assigned as high-spin iron(II) (Sugiyarto et al, 2021). Somewhat asymmetric of the doublet is diagnostic, and it is presumably associated with the presence of a very small fraction of singlet state iron(II), as indicated by the room temperature magnetic moment.…”

Section: Mössbauer Effectmentioning

confidence: 99%

See 1 more Smart Citation

Preparation of [Fe(paptH)2] (CF3SO3)2 and [Fe(paptH)2] [Fe(CN)5NO] (paptH = bis(2-(pyridin-2-ylamino)-4-(pyridin-2-yl)thiazole: Magnetic, Mössbauer, and Electronic Spectral Properties

Sugiyarto

Goodwin

2022

molekul

View full text Add to dashboard Cite

Complexes of [Fe(paptH)2][X]2.nH2O, (paptH = 2-(pyridin-2-ylamino)-4-(pyridin-2-yl)- thiazole, X = CF3SO3 and n = 1.5, and X2 = [Fe(CN)5NO] and n = 3) have been characterized in magnetic, Mössbauer, and electronic spectral properties. The studies reveal that the two complexes are predominantly quintet state at room temperature, but singlet at low temperature (below 91K). The change is assigned as a thermally spin state transition, singlet 1A1g (LS, low-spin) ↔ quintet 5T2g (HS, high-spin), in iron(II), being gradual, continuous, and incomplete at the experimental temperature range, and without hysteresis in these instances. The two complexes were yellowish brown at room temperature (~ 298K) but darkening to reddish brown at the lower temperatures.

show abstract

“…While the distortion is most prevalent in [Fe(bpp) 2 ] 2+ chemistry, it also occurs in high-spin iron(II) complexes of other tris -heterocyclic ligands, − and in related complexes of high-spin iron(III), − manganese(II), − cobalt(II), − and zinc(II). − In high-spin iron(II) complexes, the distortion electronically resembles a Jahn–Teller distortion of a 5 E ground state (in D 2d symmetry), which is favored in complexes of tridentate ligands with a narrow bite angle. , However, distortion also occurs in complexes with an orbital singlet ground state. In that case, the absence of a ligand field stabilization energy makes their coordination geometry more susceptible to deformations induced by crystal packing.…”

Section: Introductionmentioning

confidence: 99%

A Survey of the Angular Distortion Landscape in the Coordination Geometries of High-Spin Iron(II) 2,6-Bis(pyrazolyl)pyridine Complexes

Capel Berdiell,

Michaels,

Munro

et al. 2024

Inorg. Chem.

View full text Add to dashboard Cite

Reaction of 2,4,6-trifluoropyridine with sodium 3,4dimethoxybenzenethiolate and 2 equiv of sodium pyrazolate in tetrahydrofuran at room temperature affords 4-(3,4-dimethoxyphenylsulfanyl)-2,6-di(pyrazol-1-yl)pyridine (L), in 30% yield. The iron(II) complexes [FeL 2 ][BF 4 ] 2 (1a) and [FeL 2 ][ClO 4 ] 2 (1b) are high-spin with a highly distorted six-coordinate geometry. This structural deviation from ideal D 2d symmetry is common in highspin [Fe(bpp) 2 ] 2+ (bpp = di{pyrazol-1-yl}pyridine) derivatives, which are important in spin-crossover materials research. The magnitude of the distortion in 1a and 1b is the largest yet discovered for a mononuclear complex. Gas-phase DFT calculations at the ω-B97X-D/6-311G** level of theory identified four minimum or local minimum structural pathways across the distortion landscape, all of which are observed experimentally in different complexes. Small distortions from D 2d symmetry are energetically favorable in complexes with electron-donating ligand substituents, including sulfanyl groups, which also have smaller energy penalties associated with the lowest energy distortion pathway. Natural population analysis showed that these differences reflect greater changes to the Fe−N{pyridyl} σ-bonding as the distortion proceeds, in the presence of more electron-rich pyridyl donors. The results imply that [Fe(bpp) 2 ] 2+ derivatives with electron-donating pyridyl substituents are more likely to undergo cooperative spin transitions in the solid state. The high-spin salt [Fe(bpp) 2 ][CF 3 SO 3 ] 2 , which also has a strong angular distortion, is also briefly described and included in the analysis.

show abstract

Structural, magnetic and Mössbauer spectroscopic studies of the [Fe(3-bpp)₂](CF₃COO)₂ complex: role of crystal packing leading to an incomplete Fe(ii) high spin ⇋ low spin transition

Abstract: Single crystal X-ray diffraction, magnetic and 57Fe Mӧssbauer spectroscopic studies of a new iron(II)-based spin transition complex - [Fe(3-bpp)2](CF3COO)2 (bpp = 2,6-bis(pyrazol-3-yl)pyridine) are reported. The complex exhibits an incomplete thermal...

Cited by 8 publications

References 46 publications

Triflate vs Acetonitrile: Understanding the Iron(II)-Based Coordination Chemistry of Tri(quinolin-8-yl)amine

Triflate vs Acetonitrile: Understanding the Iron(II)-Based Coordination Chemistry of Tri(quinolin-8-yl)amine

Preparation of [Fe(paptH)2] (CF3SO3)2 and [Fe(paptH)2] [Fe(CN)5NO] (paptH = bis(2-(pyridin-2-ylamino)-4-(pyridin-2-yl)thiazole: Magnetic, Mössbauer, and Electronic Spectral Properties

A Survey of the Angular Distortion Landscape in the Coordination Geometries of High-Spin Iron(II) 2,6-Bis(pyrazolyl)pyridine Complexes

Contact Info

Product

Resources

About

Structural, magnetic and Mössbauer spectroscopic studies of the [Fe(3-bpp)2](CF3COO)2 complex: role of crystal packing leading to an incomplete Fe(ii) high spin ⇋ low spin transition

Abstract: Single crystal X-ray diffraction, magnetic and 57Fe Mӧssbauer spectroscopic studies of a new iron(II)-based spin transition complex - [Fe(3-bpp)2](CF3COO)2 (bpp = 2,6-bis(pyrazol-3-yl)pyridine) are reported. The complex exhibits an incomplete thermal...

Cited by 8 publications

References 46 publications

Triflate vs Acetonitrile: Understanding the Iron(II)-Based Coordination Chemistry of Tri(quinolin-8-yl)amine

Triflate vs Acetonitrile: Understanding the Iron(II)-Based Coordination Chemistry of Tri(quinolin-8-yl)amine

Preparation of [Fe(paptH)2] (CF3SO3)2 and [Fe(paptH)2] [Fe(CN)5NO] (paptH = bis(2-(pyridin-2-ylamino)-4-(pyridin-2-yl)thiazole: Magnetic, Mössbauer, and Electronic Spectral Properties

A Survey of the Angular Distortion Landscape in the Coordination Geometries of High-Spin Iron(II) 2,6-Bis(pyrazolyl)pyridine Complexes

Contact Info

Product

Resources

About

Structural, magnetic and Mössbauer spectroscopic studies of the [Fe(3-bpp)₂](CF₃COO)₂ complex: role of crystal packing leading to an incomplete Fe(ii) high spin ⇋ low spin transition