Taming salophen in rare earth metallocene chemistry

2023

Inorg. Chem. Front.

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Section: Resultsmentioning

confidence: 95%

From unprecedented 2,2′-bisimidazole-bridged rare earth organometallics to magnetic hysteresis in the dysprosium congener

Benner

2023

Inorg. Chem. Front.

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“…39 The TPSSh functional was chosen due to its well-established performance with Y metal complexes. 26,71 The final geometry was optimized at the def2-TZVP level of theory, 41,42 including the 28 in-core electron pseudopotential (ECP28MDF) and GD3 empirical dispersion correction. 41,44 An energetic minimum was not reached when considering the entire structure of 1, due to the large number of degrees of freedom caused by the trimethylsilyl groups.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…1 was optimized using the TPSSh hybrid meta-GGA functional . The TPSSh functional was chosen due to its well-established performance with Y metal complexes. , The final geometry was optimized at the def2-TZVP level of theory, , including the 28 in-core electron pseudopotential (ECP28MDF) and GD3 empirical dispersion correction. , An energetic minimum was not reached when considering the entire structure of 1 , due to the large number of degrees of freedom caused by the trimethylsilyl groups. To reduce the number of degrees of freedom, a simplified structure was defined where each trimethylsilyl group was replaced by a methyl unit.…”

Section: Resultsmentioning

confidence: 99%

“…Such compounds are highly profitable for insertion, salt metathesis, − and small-molecule activation , reactions. The isolation of mononuclear heteroleptic compounds has been carried out containing ligands such as ammonia, 2,2′-azobispyridine, and dibenzocyclooctatetraene and multinuclear complexes with diamagnetic or paramagnetic bridges derived from 2,2-bipyrimidine, , bisbenzimidazole, bismuth, dinitrogen, hexaazatrinaphthylene, phenazine, salophen, phosphaalkenes, and tetrapyridylpyrazine …”

Section: Introductionmentioning

confidence: 99%

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Guanidinate Rare-Earth Tetraphenylborate Complexes and Their Prospects in Single-Molecule Magnetism

Delano

Crystal Growth & Design

2023

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The pursuit of higher-nuclearity rare-earth-metal clusters necessitates adequate ancillary ligand scaffolds as well as easily dissociable counterions. To this end, guanidinate anions are advantageous owing to their highly customizable, sterically encumbering, anionic charged framework. Here, we present the two mononuclear guanidinate rare-earth complexes [{(Me3Si)2NC(NiPr)2}2RE][(μ-η6-Ph)(BPh3)], (RE = Y (1), Dy (2)), featuring inner-sphere tetraphenylborate anions. Each complex is sterically congested and comprises a metal ion that is ligated by two ancillary guanidinate ions and one tetraphenylborate ligand. The isostructural compounds, 1 and 2, were synthesized from a protonolysis reaction between guanidinate alkyl complexes and [HNEt3][BPh4]. The isolated molecules were characterized by X-ray crystallography and IR, NMR, and UV–vis spectroscopy. The crowded coordination sphere around each metal ion implemented by the ancillary guanidinate ligands causes the tetraphenylborate ion to adopt a rare η6-binding mode where the metal center interacts asymmetrically with the carbon atoms of one phenyl ring. DFT and NBO calculations carried out on 1 provide insight into a complicated bonding picture between one of the phenyl rings of the BPh4 – moiety and the rare-earth ion. Furthermore, the dysprosium congener, 2, is a single-molecule magnet displaying slow magnetic relaxation under the application of a static dc field.

“…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%

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

Castellanos

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.