Synthesis and characterisation of two Cu(I) metalloligands based on tetradentate tripodal ligands

Li, Li; Craze, Alexander R.; Fanna, Daniel J.; Brock, Aidan J.; Clegg, Jack K.; Lindoy, Leonard F.; Aldrich‐Wright, Janice R.; Reynolds, Jason K.; Li, Feng

doi:10.1016/j.poly.2016.08.049

“…The complex may act as a metalloligand towards further metal ions, similar to our previous work. [38][39][40][41][42][43] Figure 1. Schematic of the proposed mechanism for fast and slow cooling routes in 1.…”

Section: Hs-hs] [Hs-ls]/[ls-hs] and [Ls-ls] The Physical Bridging Of ...mentioning

confidence: 99%

Unique Spin Crossover Pathways Differentiated by Scan Rate in a New Dinuclear Fe(II) Triple Helicate: Mechanistic Deductions Enabled by Synchrotron Radiation Studies

Wallis

¹

,

Craze

²

,

Zenno

³

et al. 2022

Preprint

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The achievement of targeted properties in spin crossover (SCO) materials is complicated by often unpredictable cooperative interactions in the solid state. Herein, we report a dinuclear Fe(II) triple helicate 1, which is a rare example of a SCO material possessing two distinct magnetic behaviors that depend upon the thermal scan rate. Desolvated 1 was seen to undergo spin transition (ST) which was complete following slow cooling (1 K min-1), but incomplete ST (corresponding to 50% conversion) on fast cooling (10 K min-1). The incomplete ST observed in the latter case was accompanied by a higher temperature onset of ST, differing from TIESST (Temperature-Induced Excited Spin-State Trapping) materials. The two SCO pathways have been shown to arise from the interconversion between two structural phases (a and b), with both phases having associated high spin (HS) and low spin (LS) states. SCXRD (Single Crystal X-ray Diffraction) experiments using controlled cooling rates and a synchrotron light source enabled short collection times (2-3 minutes per dataset) which has enabled the identification of a mechanism by which the slow-cooled material may fully relax. In contrast, fast-cooled materials exhibit disordered arrangements of multiple structural phases, which has in turn revealed that the [HS-LS] ↔ [LS-HS] equilibria are controllable in the solid by varying the scan rate. Such behavior has been previously observed in solution studies, but its control in solids has not been reported up to now. This study demonstrates how intermolecular cooperativity can allow multiple distinct magnetic behaviors, and provides some insight into how [HS-LS] ↔ [LS-HS] equilibria can be controlled in the solid state, which may assist in the design of next-generation logic and signaling devices.

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“…The similarity of this spectrum with that of the free ligand suggests that these two bands are assigned to the intraligand transitions n→ 𝜋* and 𝜋 → 𝜋* respectively [23,28,34]. In the visible range, the spectrum shows the presence of three lowintensity bands at 403, 536, 606 nm which can be attributed to the LMCT or MLCT transitions [59,60]. The spectrum also shows the presence of a band at 699 nm characteristic of a d-d electronic transition of a Cu(II) ion of configuration d 9 electronics adopting octahedral coordination geometry [61].…”

Section: (B) C•••h/h•••c 246 (C) N•••h/h•••n 179 (D) S•••h/h•••s 164 (E) C•••c 80 (F) H•••h 58 (G) S•••cu/cu•••s 57 (H) N•••cu/cu••mentioning

confidence: 72%

Unusual mixed-valence CuII/CuI coordination polymer based on 2,5-bis(pyridine-2-yl)-1,3,4-thiadiazole and thiocyanate: Synthesis, structural characterization and antimicrobial in vitro activity assessment

Laachir

¹

,

Zine

²

,

Guesmi

³

et al. 2021

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“…The complex may act as a metalloligand towards further metal ions, similar to our previous work. [38][39][40][41][42][43] Two distinct SCO pathways were observed in single crystals with the former dependent on the scan rate of the temperature (Figure 1). Structural reorientation of key chemical moieties in the three semirigid linker ligands L upon SCO produces steric interactions, whereby adjacent helicate molecules in the lattice impose steric influences on one another.…”

Section: Hs-hs] [Hs-ls]/[ls-hs] and [Ls-ls] The Physical Bridging Of ...mentioning

confidence: 97%

Unique Spin Crossover Pathways Differentiated by Scan Rate in a New Dinuclear Fe(II) Triple Helicate: Mechanistic Deductions Enabled by Synchrotron Radiation Studies

Wallis

¹

,

Craze

²

,

Zenno

³

et al. 2022

Preprint

0

View full text Add to dashboard Cite

The achievement of targeted properties in spin crossover (SCO) materials is complicated by often unpredictable cooperative interactions in the solid state. Herein, we report a dinuclear Fe(II) triple helicate 1, which is a rare example of a SCO material possessing two distinct magnetic behaviors that depend upon the thermal scan rate. Desolvated 1 was seen to undergo spin transition (ST) which was complete following slow cooling (1 K min-1), but incomplete ST (corresponding to 50% conversion) on fast cooling (10 K min-1). The incomplete ST observed in the latter case was accompanied by a higher temperature onset of ST, differing from TIESST (Temperature-Induced Excited Spin-State Trapping) materials. The two SCO pathways have been shown to arise from the interconversion between two structural phases (a and b), with both phases having associated high spin (HS) and low spin (LS) states. SCXRD (Single Crystal X-ray Diffraction) experiments using controlled cooling rates and a synchrotron light source enabled short collection times (2-3 minutes per dataset) which has enabled the identification of a mechanism by which the slow-cooled material may fully relax. In contrast, fast-cooled materials exhibit disordered arrangements of multiple structural phases, which has in turn revealed that the [HS-LS] ↔ [LS-HS] equilibria are controllable in the solid by varying the scan rate. Such behavior has been previously observed in solution studies, but its control in solids has not been reported up to now. This study demonstrates how intermolecular cooperativity can allow multiple distinct magnetic behaviors, and provides some insight into how [HS-LS] ↔ [LS-HS] equilibria can be controlled in the solid state, which may assist in the design of next-generation logic and signaling devices.

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Synthesis and characterisation of two Cu(I) metalloligands based on tetradentate tripodal ligands

Abstract: This paper is a contribution to a Special Issue concerned with the applications of tridentate and tetradentate tripodal ligands.

Cited by 6 publications

References 23 publications

Unique Spin Crossover Pathways Differentiated by Scan Rate in a New Dinuclear Fe(II) Triple Helicate: Mechanistic Deductions Enabled by Synchrotron Radiation Studies

Unique Spin Crossover Pathways Differentiated by Scan Rate in a New Dinuclear Fe(II) Triple Helicate: Mechanistic Deductions Enabled by Synchrotron Radiation Studies

Unusual mixed-valence CuII/CuI coordination polymer based on 2,5-bis(pyridine-2-yl)-1,3,4-thiadiazole and thiocyanate: Synthesis, structural characterization and antimicrobial in vitro activity assessment

Unique Spin Crossover Pathways Differentiated by Scan Rate in a New Dinuclear Fe(II) Triple Helicate: Mechanistic Deductions Enabled by Synchrotron Radiation Studies

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