Synthesis of heteroleptic yttrium and dysprosium 1,2,4-tris(trimethylsilyl)cyclopentadienyl complexes

Corner, Sophie C.; Goodwin, Conrad A. P.; Ortu, Fabrizio; Evans, Peter; Zhang, Hongrui; Gransbury, Gemma K.; Whitehead, George F. S.; Mills, David P.

doi:10.1071/ch21314

Cited by 3 publications

(7 citation statements)

References 80 publications

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“…Isolated dysprosocenium cations have a maximum cluster size of 7.1% SA and a mean largest cluster size of 3.2% SA, reflecting their highly sterically hindered geometries. Fragments with a single equatorial coordination site, n = 1, have binding sites of 14.5–20.4% SA, enabling the coordination of a single halide (Cl, Br, I) or borohydride ligand; these compounds are often used as precursors to isolated dysprosocenium cations. − ,, Dysprosocenium fragments that allow for the coordination of multiple ligands or multidentate ligands ( n ≥ 2) have a minimum largest cluster of 20.8% SA. Hence, the threshold for single equatorial interactions from this data set is between 7.1 and 14.5% SA, and ∼20.5% SA is the threshold for multiple equatorial interactions.…”

Section: Resultsmentioning

confidence: 99%

“…The solid-state structures of 1–4-Ln , 5%Dy@4-Y , 5, and 6-Dy were determined by SCXRD; the structures of 1-Ln have also recently been reported by Price et al (the SIP 3-Dy·C 6 H 6 and CIP 4-Dy are depicted in Figure and selected metrical parameters are compiled in Table ; see Figures S64–S72 and Tables S8–S13 for all other structures and supporting crystallographic data). As 1–4-Y are structurally analogous to Dy homologues, numerous similar complexes to 1-Ln and 2-Ln are known in the literature, ,,− and the 5%Dy@4-Y SCXRD data set represents a P 1̅ polymorph present only as a minor CIP phase in bulk 5%Dy@4-Y , we limit our discussion to 3-Dy·C 6 H 6 and 4-Dy here for brevity. The SIP 3-Dy·C 6 H 6 cocrystallizes with benzene in the Pbca space group, while no lattice solvent is present for the CIP 4-Dy , which crystallizes in P 2 1 / c .…”

Section: Resultsmentioning

confidence: 99%

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AtomAccess: A Predictive Tool for Molecular Design and Its Application to the Targeted Synthesis of Dysprosium Single-Molecule Magnets

Gransbury,

Corner,

Kragskow

et al. 2023

J. Am. Chem. Soc.

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Isolated dysprosocenium cations, [Dy(CpR)2]+ (CpR = substituted cyclopentadienyl), have recently been shown to exhibit superior single-molecule magnet (SMM) properties over closely related complexes with equatorially bound ligands. However, gauging the crossover point at which the CpR substituents are large enough to prevent equatorial ligand binding, but small enough to approach the metal closely and generate strong crystal field splitting has required laborious synthetic optimization. We therefore created the computer program AtomAccess to predict the accessibility of a metal binding site and its ability to accommodate additional ligands. Here, we apply AtomAccess to identify the crossover point for equatorial coordination in [Dy(CpR)2]+ cations in silico and hence predict a cation that is at the cusp of stability without equatorial interactions, viz., [Dy(Cpttt)(Cp*)]+ (Cpttt = C5H2 t Bu3-1,2,4, Cp* = C5Me5). Upon synthesizing this cation, we found that it crystallizes as either a contact ion-pair, [Dy(Cpttt)(Cp*){Al[OC(CF3)3]4-κ-F}], or separated ion-pair polymorph, [Dy(Cpttt)(Cp*)][Al{OC(CF3)3}4]·C6H6. Upon characterizing these complexes, together with their precursors, yttrium and yttrium-doped analogues, we find that the contact ion-pair shows inferior SMM properties to the separated ion-pair, as expected, due to faster Raman and quantum tunneling of magnetization relaxation processes, while the Orbach region is relatively unaffected. The experimental verification of the predicted crossover point for equatorial coordination in this work tests the limitations of the use of AtomAccess as a predictive tool and also indicates that the application of this type of program shows considerable potential to boost efficiency in exploratory synthetic chemistry.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

AtomAccess: A Predictive Tool for Molecular Design and Its Application to the Targeted Synthesis of Dysprosium Single-Molecule Magnets

Gransbury,

Corner,

Kragskow

et al. 2023

J. Am. Chem. Soc.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Fragments with a single equatorial coordination site, n = 1, have binding sites of 14.5-20.4% SA, enabling the coordination of a single halide (Cl, Br, I) or borohydride ligand; these compounds are often used as precursors to isolated dysprosocenium cations. [14][15][16][17][18][19]22,48 Dysprosocenium fragments that allow the coordination of multiple ligands or multi-dentate ligands (n ≥ 2) have a minimum largest cluster of 20.8% SA. Hence, the threshold for single equatorial interactions from this dataset is between 7.1 and 14.5% SA, and ~20.5% SA is the threshold for multiple equatorial interactions.…”

Section: Atomaccess Calculationsmentioning

confidence: 99%

“…Axial complexes featuring {Ln(Cp ttt )(Cp*)} motifs were prepared by multistep procedures that adapted a combination of literature protocols (Scheme 1). 18,19,48,[50][51][52][53][54] The separate salt…”

Section: Synthesismentioning

confidence: 99%

AtomAccess: A predictive tool for molecular design and its application to the targeted synthesis of dysprosium single-molecule magnets

Gransbury

Corner

Kragskow

et al. 2023

Preprint

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Isolated dysprosocenium cations, [Dy(CpR)2]+ (CpR = substituted cyclopentadienyl), have recently been shown to exhibit superior single-molecule magnet (SMM) properties over closely related complexes with equatorially-bound ligands. However, gauging the crossover point at which the CpR substituents are large enough to prevent equatorial ligand binding, but small enough to approach the metal closely and generate strong crystal field splitting, has required laborious synthetic optimization. We therefore created the computer program, AtomAccess, to predict the accessibility of a metal binding site and its ability to accommodate additional ligands. Here we apply AtomAccess to rapidly screen a series of derivatized dysprosium metallocene fragments of varying steric bulk in silico, allowing us to identify the crossover point for equatorial coordination in [Dy(CpR)2]+ cations, and hence predict a cation that is at the cusp of stability without equatorial interactions, viz. [Dy(Cpttt)(Cp*)]+ (Cpttt = C5H2tBu3-1,2,4, Cp* = C5Me5). Upon synthesizing this cation we found it crystallizes as either a contact ion-pair, [Dy(Cpttt)(Cp*){Al[OC(CF3)3]4-k-F}], or separated ion-pair polymorph, [Dy(Cpttt)(Cp*)][Al{OC(CF3)3}4]C6H6. These complexes, together with their precursors and yttrium analogs, have been characterized by NMR and ATR-IR spectroscopy, elemental analysis, powder and single crystal X-ray diffraction, SQUID magnetometry and ab initio calculations. We find that the contact ion-pair shows inferior SMM properties to the separated ion-pair, as expected, due to faster Raman and quantum tunneling of magnetization relaxation processes. The experimental verification of the predicted crossover point for equatorial coordination in this work indicates that programs like AtomAccess have significant potential to boost efficiency in exploratory synthetic chemistry.

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“…Lanthanide-centered single-ion magnets (SIMs) have been a growing research field mainly due to the success of lanthanocenium chemistry. − These moieties are designed around heavily substituted bis -capped cyclopentadienyl [Ln(Cp R ) 2 ] + (R = alkyl, − ,,− aryl, , and silyl , ) complexes targeting several single-molecule magnet (SMM) metrics, such as large effective anisotropic energy barrier to the reversal of magnetization ( U eff ), high magnetic blocking temperature ( T B ), and hysteretic temperature ( T H ). The current state-of-the-art complexes show a vast improvement since the discovery of SMM behavior in polymetallic transitional metal clusters .…”

Section: Introductionmentioning

confidence: 99%

Increasing the Symmetry around Lanthanide Ions: The Effect on Single-Ion Magnet Behavior and Electronic Structure

Thomas,

Giansiracusa,

Mole

et al. 2023

Crystal Growth & Design

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Bis-capped lanthanide compounds have dominated the single-ion magnet (SIM) field with little variation in design. Herein, we report the new synthesis of the lanthanide compounds [Ln(Tp 2-py ) 2 ](BPh 4 ) (1-Ln; Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, and Dy), which employ the use of the hexadentate hydrotris[3-(2′pyridyl)-pyrazol-1-yl]borate (Tp 2-py ) ligand to encapsulate lanthanide ions in pseudo-icosahedral crystal fields. The extension of the latter lanthanide ions yields the hydrated compounds [Ln(κ 4 -Tp 2-py ) 2 (OH 2 )](BPh 4 ) (2-Ln; Ln = Dy, Y, Ho, Er, Tm, Yb, and Lu) instead due to the decrease in the ionic radii of the lanthanide and steric demand of the ligand. Alternating current magnetometry studies on 1-Ce, 1-Tb, 1-Dy, 2-Dy, and [Dy(Tp 2-py ) 2 Cl] (3) revealed slow magnetic relaxation in applied magnetic fields for all compounds, with 1-Tb revealing an extractable Orbach regime with U eff = 46(2) cm −1 , while the remaining compounds are dominated by Raman relaxation mechanisms. The complexity and size of Tp 2-py likely afford many low energy vibrational modes which would be responsible for an increase in spin-phonon coupling and the observed dominance of Raman relaxation. CASSCF calculations on the compounds showed that the ground state purity is heavily dependent on the lanthanide; however, all easy axes are aligned with the B•••B axis (or pseudo B•••B axis for the case of 3) except for 2-Dy, where the easy axis aligns with the Dy−OH 2 bond. The resonant nature of the tris-(pyrazolyl)borate ligands results in diffusely spread charge distribution, minimizing the influence of the axially located boron atoms, resulting in the lanthanide ion being encapsulated in a "pseudosphere" of negative charge, impacting the overall crystal field splitting. The magnetic behavior and electronic structure of 1-Ln highlight the importance of low energy vibrational modes to mitigate spin-phonon coupling, charge distribution, and geometry of ligands when designing lanthanide-based SIMs.

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Synthesis of heteroleptic yttrium and dysprosium 1,2,4-tris(trimethylsilyl)cyclopentadienyl complexes

Abstract: Synthesis of heteroleptic yttrium and dysprosium 1,2,4-tris(trimethylsilyl)cyclopentadienyl complexes

Cited by 3 publications

References 80 publications

AtomAccess: A Predictive Tool for Molecular Design and Its Application to the Targeted Synthesis of Dysprosium Single-Molecule Magnets

AtomAccess: A Predictive Tool for Molecular Design and Its Application to the Targeted Synthesis of Dysprosium Single-Molecule Magnets

AtomAccess: A predictive tool for molecular design and its application to the targeted synthesis of dysprosium single-molecule magnets

Increasing the Symmetry around Lanthanide Ions: The Effect on Single-Ion Magnet Behavior and Electronic Structure

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