Cyclooctatetraenide-based single-ion magnets featuring bulky cyclopentadienyl ligand

Korzyński, Maciej D.; Bernhardt, Moritz; Romankov, Vladyslav; Dreiser, Jan; Matmon, Guy; Pointillart, Fabrice; Guennic, Boris Le; Cador, Olivier; Copéret, Christophe

doi:10.1039/d2sc02560d

Cited by 10 publications

(15 citation statements)

References 40 publications

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“…The characterization of 1 Er result provides a new opportunity to interpret the SMM properties with a qualitative model that considers interactions between the prolate‐shaped 4 f electron density of Er 3+ and the crystal field. Here, we use [(η 8 ‐COT)Er(η 5 ‐Cp ttt )] ( 2 , Cp ttt =1,2,4‐C 5 t Bu 3 H 2 ) as the benchmark since this SMM shows a single thermally activated Orbach process with U eff =228.26 cm −1 [14a] …”

Section: Resultsmentioning

confidence: 99%

Dynamic Magnetic Properties of Germole‐ligated Lanthanide Sandwich Complexes

Mondal

Ruan

et al. 2023

Chemistry A European J

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The first germole-ligated single-molecule magnets are reported, with contrasting properties found for the nearlinear sandwich complexes [(η 8 -COT)Ln(η 5 -Cp Ge ] À , where Ln=Dy (1 Dy ) or Er (1 Er ), COT is cyclo-octatetraenyl and Cp Ge is [GeC 4 -2,5-(SiMe 3 ) 2 -3,4-Me 2 ] 2À . Whereas 1 Er has an energy barrier of 120(1) cm À 1 in zero applied field and open hysteresis loops up to 10 K, the relaxation in 1 Dy is characterized by quantum tunneling within the ground state.

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Section: Resultsmentioning

confidence: 99%

Dynamic Magnetic Properties of Germole‐ligated Lanthanide Sandwich Complexes

Mondal

Ruan

et al. 2023

Chemistry A European J

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“…By comparison, the π-aromatic pentamethylcyclopentadienyl (Cp*) and methylcyclopentadienyl (Cp Me ) ligands have been estimated to contribute −100 and −124 ppm per ligand, respectively. , This expands the limited library of known chemical shifts contributions for 89 Y NMR data on yttrium cyclopentadienyl and cyclooctatetraenyl complexes (Table ). ,,,− …”

Section: Resultsmentioning

confidence: 99%

“…The synthesis and characterization of COT-based complexes contribute to our understanding of bonding in metal complexes . Furthermore, 1 will pave the way for heavier analogues that would be relevant for applications in areas such as catalysis, , molecular nanowires, small-molecule activation, and single-molecule magnetism. ,− In addition, compounds of this class representing polycyclic systems will be potentially relevant in photoredox chemistry …”

Section: Introductionmentioning

confidence: 99%

Linear, Electron-Rich, Homoleptic Rare Earth Metallocene and Its Redox Activity

Castellanos

Demir

2023

Inorg. Chem.

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The first homoleptic sandwich complex of dibenzocyclooctatetraene (dbCOT), representing a large cyclooctatetraene (COT) ligand with two fused benzene moieties, for any metal was accessed through salt metathesis of YCl 3 with K 2 dbCOT in the presence of 2.2.2-cryptand. Single-crystal X-ray diffraction analysis on red-brown [K(crypt-222)][Y(dbCOT) 2 ], 1, revealed a remarkably linear anionic yttrocene complex featuring a centroid−yttrium−centroid angle of 180.0°. The anionic moiety adopts a pseudo D 2d geometry, where the carbon atoms of the central COT ring exhibit a staggered geometry. In total, 36 πelectrons are stored on both dbCOT anions, rendering it the largest isolated sandwich complex containing only fused aromatic rings. The solution-state structure of 1 was probed through a series of techniques involving cyclic voltammetry, UV−vis, and 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, including 89 Y NMR. The density functional theory (DFT) and natural bond orbital (NBO) analysis uncovered an ionic bonding interaction between the (dbCOT) 2− ligands and Y III ion. NICS calculations support the experimentally observed aromatic character of 1, despite the deviation from planarity found in the dbCOT moieties. The cyclic voltammograms allude to the accessibility of a radical oxidation state, dbCOT 3−• , based on a quasi-reversible feature. Excitingly, the chemical one-electron reduction of 1 through exposure to potassium graphite yielded a paramagnetic molecule, which was detected by electron paramagnetic resonance (EPR) techniques. Notably, this EPR spectrum is the first one for any sandwich complex containing a COT radical. Remarkably, 1 is thermally stable, and its isolation may provide access to mono-and multinuclear complexes comprising heavier metals with applications in small-molecule activation, single-molecule magnetism, and molecular nanowires.

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“…7) that was reported with record SMMs properties at the time. 183 The use of heteroleptic ligands for the formation of neutral -sandwich complexes was also investigated and led to good SMMs properties, 184,185 particularly with the large monoanionic Cnt ligand. 186,187 The Cot-Er pair is highly relevant as an excellent example of the perfect adequation between the metal and the ligand coordination for maximal anisotropy: this is referred to as ligand-metal pair anisotropy.…”

Section: Single-ion Magnet Designmentioning

confidence: 99%