Structure and Magnetization Dynamics of Dy−Fe and Dy−Ru Bonded Complexes

Burns, Corey P.; Yang, Xin; Wofford, Joshua D.; Bhuvanesh, Nattamai; Hall, Michael B.; Nippe, Michael

doi:10.1002/anie.201803761

Cited by 41 publications

(24 citation statements)

References 55 publications

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“…The equatorial coordination sites comprises the ligands X, whose presence diminish the axiality, meaning that the SMM properties vary to an extent that depends on the μ-bridging ligand. The results of our studies are consistent with those reported by others on related metallocene SMMs, notably Long, Nippe, and Gao and Wang. − …”

Section: Magnetic Properties Of Dysprosium Metallocene Smmsmentioning

confidence: 82%

Cyclopentadienyl Ligands in Lanthanide Single-Molecule Magnets: One Ring To Rule Them All?

2018

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The discovery of materials capable of storing magnetic information at the level of single molecules and even single atoms has fueled renewed interest in the slow magnetic relaxation properties of single-molecule magnets (SMMs). The lanthanide elements, especially dysprosium, continue to play a pivotal role in the development of potential nanoscale applications of SMMs, including, for example, in molecular spintronics and quantum computing. Aside from their fundamentally fascinating physics, the realization of functional materials based on SMMs requires significant scientific and technical challenges to be overcome. In particular, extremely low temperatures are needed to observe slow magnetic relaxation, and while many SMMs possess a measurable energy barrier to reversal of the magnetization ( U), very few such materials display the important properties of magnetic hysteresis with remanence and coercivity. Werner-type coordination chemistry has been the dominant method used in the synthesis of lanthanide SMMs, and most of our knowledge and understanding of these materials is built on the many important contributions based on this approach. In contrast, lanthanide organometallic chemistry and lanthanide magnetochemistry have effectively evolved along separate lines, hence our goal was to promote a new direction in single-molecule magnetism by uniting the nonclassical organometallic synthetic approach with the traditionally distinct field of molecular magnetism. Over the last several years, our work on SMMs has focused on obtaining a detailed understanding of why magnetic materials based on the dysprosium metallocene cation building block {CpDy} display slow magnetic relaxation. Specifically, we aspired to control the SMM properties using novel coordination chemistry in a way that hinges on key considerations, such as the strength and the symmetry of the crystal field. In establishing that the two cyclopentadienyl ligands combine to provide a strongly axial crystal field, we were able to propose a robust magneto-structural correlation for understanding the properties of dysprosium metallocene SMMs. In doing so, a blueprint was established that allows U and the magnetic blocking temperature ( T) to be improved in a well-defined way. Although experimental discoveries with SMMs occur more rapidly than quantitative theory can (currently) process and explain, a clear message emanating from the literature is that a combination of the two approaches is most effective. In this Account, we summarize the main findings from our own work on dysprosium metallocene SMMs, and consider them in the light of related experimental studies and theoretical interpretations of related materials reported by other protagonists. In doing so, we aim to contribute to the nascent and healthy debate on the nature of spin dynamics in SMMs and allied molecular nanomagnets, which will be crucial for the further advancement of this vibrant research field.

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Section: Magnetic Properties Of Dysprosium Metallocene Smmsmentioning

confidence: 82%

Cyclopentadienyl Ligands in Lanthanide Single-Molecule Magnets: One Ring To Rule Them All?

2018

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“…The recent emergence of coordination compounds containing metal–metal bonds between transition metals (TMs) and rare earth (RE) elements, that is, the group 3 metals and the lanthanides (Ln), has inspired their use in diverse applications. − For example, TM–RE bonded complexes are currently being explored for single-molecule magnetism. , In the realm of catalysis, multimetallic cooperativity between rare earth ions and transition metals can elicit beneficial activity in both heterogeneous , and cluster − systems by affecting the catalyst stability, electronics, and/or substrate binding affinity. Even so, direct TM–RE bonds, especially those involving lanthanides, are rarely seen in homogeneous catalysis.…”

Section: Introductionmentioning

confidence: 99%

Rare-Earth Supported Nickel Catalysts for Alkyne Semihydrogenation: Chemo- and Regioselectivity Impacted by the Lewis Acidity and Size of the Support

Ramirez

2020

J. Am. Chem. Soc.

108

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Bimetallic catalysts of nickel(0) with a trivalent rare-earth ion or Ga(III), NiML3 (where L is [iPr2PCH2NPh]−, and M is Sc, Y, La, Lu, or Ga), were investigated for the selective hydrogenation of diphenylacetylene (DPA) to (E)-stilbene. Each bimetallic complex features a relatively short Ni–M bond length, ranging from 2.3395(8) Å (Ni–Ga) to 2.5732(4) Å (Ni–La). The anodic peak potentials of the NiML3 complexes vary from −0.48 V to −1.23 V, where the potentials are negatively correlated with the Lewis acidity of the M(III) ion. Three catalysts, Ni–Y, Ni–Lu, and Ni–Ga, showed nearly quantitative conversions in the semihydrogenation of DPA, with NiYL3 giving the highest selectivity for (E)-stilbene. Initial rate studies were performed on the two tandem catalytic reactions: DPA hydrogenation and (Z)-stilbene isomerization. The catalytic activity in DPA hydrogenation follows the order Ni–Ga > Ni–La > Ni–Y > Ni–Lu > Ni–Sc. The ranking of catalysts by (Z)-stilbene isomerization initial rates is Ni–Ga ≫ Ni–Sc > Ni–Lu > Ni–Y > Ni–La. In operando 31P and 1H NMR studies revealed that in the presence of DPA, the Ni bimetallic complexes supported by Y, Lu, and La form the Ni(η2-alkyne) intermediate, (η2-PhCCPh)Ni(iPr2PCH2NPh)2M(κ2-iPr2PCH2NPh). In contrast, the Ni–Ga resting state is the Ni(η2-H2) species, and Ni–Sc showed no detectable binding of either substrate. Hence, the mechanism of Ni-catalyzed diphenylacetylene semihydrogenation adheres to two different kinetics: an autotandem pathway (Ni–Ga, Ni–Sc) versus temporally separated tandem reactions (Ni–Y, Ni–Lu, Ni–La). Collectively, the experimental results demonstrate that modulating a base-metal center via a covalently appended Lewis acidic support is viable for promoting selective alkyne semihydrogenation.

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“…In our previous communications, we reported characterization and analysis of PyCp 2 Dy-TMCp(CO) 2 (TM = Fe, Ru; PyCp 2 2– = [2,6-(CH 2 C 5 H 3 ) 2 C 5 H 3 N] 2– ) and the (thf)Ce–Fe analogue from both experiment and theory. , Since this ligand system is apparently capable of supporting other Ln–TM complexes, we investigated Ln to TM bonds in PyCp 2 Ln-TMCp(CO) 2 (TM = Fe, Ru) ( 9 ) with detailed theoretical analyses of the La–Fe, Dy–Fe, and Lu–Fe bonds. To distinguish the nature of these unconventional Ln–Fe bonds, comparisons are made with relevant analogues, for which the bonding characteristics are more generally accepted.…”

Section: Introductionmentioning

confidence: 99%

Unsupported Lanthanide–Transition Metal Bonds: Ionic vs Polar Covalent?

et al. 2021

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Lanthanide−transition metal complexes continue to be of interest, not only because of their synthetic challenge but also of their promising magnetic properties. Computational work examining the chemical bonding between lanthanides and transition metals in PyCp 2 Ln-TMCp(CO) 2 (DyPyCp 2 2− = [2,6-(CH 2 C 5 H 3 ) 2 C 5 H 3 N] 2− ) reveals strong Ln−TM dative bonds. Gasphase optimized geometries are in good agreement with experimental structures at the density functional theory (DFT) level with large-core pseudopotentials. From La to Lu, there is a small increase in the bond dissociation energy, as well as a decrease in Ln−Fe bond lengths. Energy decomposition analyses attribute this trend to an increase in the electrostatic contribution from the decreasing bond length and a modest increase in the orbital contribution. The natural bond orbital analysis clearly indicates that 3d 6 "lone pairs" in the [FeCp(CO) 2 ] − fragment act as a Lewis bases donating nearly 0.5 electron to Ln virtual orbitals of mainly d character. The interfragment bonding was also quantified by the quantum theory of atoms in molecules, which indicates that the Ln−Fe bond is more covalent than the Ca−Fe bond in the hypothetical CpCa-FeCp(CO) 2 but less covalent than the Zn−Fe bond in the hypothetical CpZn−FeCp(CO) 2 . Further comparisons suggest that to the [PyCp 2 Ln] + cation the [FeCp(CO) 2 ] − anion appears much like a halide. Overall, these Ln−TM dative bonds appear to have strong electrostatic contributions as well as significant orbital mixing and dispersion contributions.

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Structure and Magnetization Dynamics of Dy−Fe and Dy−Ru Bonded Complexes

Cited by 41 publications

References 55 publications

Cyclopentadienyl Ligands in Lanthanide Single-Molecule Magnets: One Ring To Rule Them All?

Cyclopentadienyl Ligands in Lanthanide Single-Molecule Magnets: One Ring To Rule Them All?

Rare-Earth Supported Nickel Catalysts for Alkyne Semihydrogenation: Chemo- and Regioselectivity Impacted by the Lewis Acidity and Size of the Support

Unsupported Lanthanide–Transition Metal Bonds: Ionic vs Polar Covalent?

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