Homoleptic organolanthanide compounds supported by the bis(dimethylsilyl)benzyl ligand

Boteju, Kasuni C.; Ellern, Arkady; Sadow, Aaron D.

doi:10.1039/c6cc09304c

Cited by 15 publications

(13 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Compound 1b is a precursor for the zwitterionic complex Ce{C(SiHMe 2 ) 3 } 2 HB(C 6 F 5 ) 3 ; the latter compound catalyzes hydrosilylation of acrylates to give α-silyl esters . We also recently reported an alkyl ligand that combines features of benzyl and the β-SiHMe 2 , namely C(SiHMe 2 ) 2 Ph, and a series of its homoleptic lanthanide compounds in which the LnC 3 core is trigonal planar …”

Section: Introductionmentioning

confidence: 92%

“…37 In addition, we reported an alkyl ligand that combines features of benzyl and the β-SiHMe 2 , namely C(SiHMe 2 ) 2 Ph and a series of its homoleptic lanthanide compounds in which the LaC 3 core is trigonal planar. 38 Here, we report the full synthesis of the lightest and largest homoleptic tris(alkyl) complexes (La, Ce, Pr, and Nd). We sought easily synthesized, solvent-free, homoleptic compounds of the early rare earth elements.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Homoleptic Trivalent Tris(alkyl) Rare Earth Compounds

et al. 2017

Self Cite

View full text Add to dashboard Cite

Homoleptic tris(alkyl) rare earth complexes Ln{C(SiHMe)} (Ln = La, 1a; Ce, 1b; Pr, 1c; Nd, 1d) are synthesized in high yield from LnITHF and 3 equiv of KC(SiHMe). X-ray diffraction studies reveal 1a-d are isostructural, pseudo-C-symmetric molecules that contain two secondary Ln↼HSi interactions per alkyl ligand (six total). Spectroscopic assignments are supported by comparison with Ln{C(SiDMe)} and DFT calculations. The Ln↼HSi and terminal SiH exchange rapidly on the NMR time scale at room temperature, but the two motifs are resolved at low temperature. Variable-temperature NMR studies provide activation parameters for the exchange process in 1a (ΔH = 8.2(4) kcal·mol; ΔS = -1(2) cal·molK) and 1a-d (ΔH = 7.7(3) kcal·mol; ΔS = -4(2) cal·molK). Comparisons of lineshapes, rate constants (k/k), and slopes of ln(k/T) vs 1/T plots for 1a and 1a-d reveal that an inverse isotope effect dominates at low temperature. DFT calculations identify four low-energy intermediates containing five β-Si-H⇀Ln and one γ-C-H⇀Ln. The calculations also suggest the pathway for Ln↼HSi/SiH exchange involves rotation of a single C(SiHMe) ligand that is coordinated to the Ln center through the Ln-C bond and one secondary interaction. These robust organometallic compounds persist in solution and in the solid state up to 80 °C, providing potential for their use in a range of synthetic applications. For example, reactions of Ln{C(SiHMe)} and ancillary proligands, such as bis-1,1-(4,4-dimethyl-2-oxazolinyl)ethane (HMeC(Ox)) give {MeC(Ox)}Ln{C(SiHMe)}, and reactions with disilazanes provide solvent-free lanthanoid tris(disilazides).

show abstract

Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Homoleptic Trivalent Tris(alkyl) Rare Earth Compounds

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…The cation Ce 3+ is covalently bound to the benzhydryl ligands via the central methanide carbons; the Ce–CH bond lengths in 2 (2.571(2), 2.563(3), 2.583(2) Å) are close to each other. These bond distances are much longer than that in the three-coordinate complex [(Me 3 Si) 2 CH] 3 Ce (2.475(7) Å) and significantly shorter than that in the homoleptic complexes with [C(SiHMe 2 ) 3 ] ligands (for comparison, see: 2.672(2) Å in Ce[C(SiHMe 2 ) 3 ] 3 , , 2.671(2) Å in Ce[C(SiHMe 2 ) 2 Ph] 3, and 2.617(3) Å in Ce[Me 2 NCHC 6 H 5 ] 3 ). At the same time, the Ce–CH bond length in 2 is close to the value measured in the six-coordinate tris(benzyl) complex (C 6 H 5 CH 2 ) 3 Ce(THF) 3 (2.600(2)–2.614(2) Å) .…”

Section: Resultsmentioning

confidence: 73%

Thermally Stable Cationic Bis(benzhydryl) Complexes of Early Lanthanides (La, Ce, Nd)

2022

View full text Add to dashboard Cite

A series of base-free Ln(III) tris(benzhydryl) complexes [(p-tBu-C6H4)2CH]3Ln (Ln = La (1), Ce (2), Nd (3)) were synthesized by the salt metathesis reactions of LnCl3(THF)3.5 and [(p-tBu-C6H4)2CH]K. Cerium complex 2 similarly to the previously published congeners 1 and 3 features η4-type of coordination of benzhydryl ligands. The reactions of equimolar amounts of 1–3 and Brønsted acid [NHEt3][B(C6H5)4] allowed for the synthesis of cationic bis(alkyl) complexes of large lanthanides [{(p-tBu-C6H4)2CH}2Ln(TMEDA)][BPh4] (Ln = La (4), Ce (5), Nd (6)), which were isolated as separated ion pairs containing one TMEDA molecule coordinated with a Ln ion. In contrast, the reaction of 2 with Lewis acid B(C6F5)3 affords a base-free cationic complex [{(p-tBu-C6H4)2CH}2Ce][μ-{(p-tBu-C6H4)2CH}B(C6F5)3] (7), which adopts the structure of a contact ion pair with μ-η1:η6-bridging benzhydryl ligand. Cationic complexes 4–7 proved to be thermally stable: no decomposition was observed even after heating their solutions in toluene at 80 °C for 72 h.

show abstract

“…Similarly, the dimethylsilylbenzyl 2Ln compounds contain Ln↼H–Si interactions, which are sufficiently labile to be disrupted mechanically in a hydraulic press, as evidenced by IR experiments . The three phenyl groups coordinate to the Ln center on one side of the equatorial plane.…”

Section: Introductionmentioning

confidence: 97%

Structure and Magnetic Properties of Homoleptic Trivalent Tris(alkyl)lanthanides

et al. 2023

Self Cite

View full text Add to dashboard Cite

Six new solvent-free, homoleptic paramagnetic tris(alkyl)lanthanides Ln{C(SiHMe2)3}3 (1Ln) and Ln{C(SiHMe2)2Ph}3 (2Ln) (Ln = Gd, Dy, and Er) were synthesized to investigate the magnetic properties of 4f organometallic compounds stabilized by secondary Ln↼H–Si and benzylic interactions. The unit cell of 1Gd contains one independent molecule (Z = 2), while 1Dy and 1Er crystallize with four independent isostructural molecules per unit cell (Z = 16). In all molecules, as in other 1Ln compounds, the three tris(dimethylsilyl)methyl ligands form a trigonal planar LnC3 core, and six secondary interactions involving Ln↼H–Si bonding in Ln{C(SiHMe2)3}3 form above and below the equatorial plane. Two and five crystallographically independent molecules of each 2Ln (2Gd, Z = 8; 2Dy, Z = 20) form with three π-coordinated phenyl groups in addition to either one or two secondary Ln↼H–Si interactions per molecule. The packing of these midseries organolanthanide compounds contrasts the single crystallographically unique molecules in previously reported La{C(SiHMe2)3}3 (1La, Z = 2, Z′ = 1) and La{C(SiHMe2)2Ph}3 (2La, Z = 2, Z′ = 1/3). 2La doped with 2Dy can adopt the crystallographic structure of 2La, which promotes magnetic properties, namely a higher χm T value at low temperatures as well as stronger magnetic anisotropy. The ac susceptibility data for 10% 2Dy doped into 2La suggests slow relaxation at low temperatures with a relaxation barrier of ∼45 K. The computed saturated magnetization of 1Er (M ≈ 4.5 μB) and 1Dy (M ≈ 6 μB) matches the experimental values, while the computed value for 2Dy better matches the value measured for 2Dy diluted in 2La (M ≈ 5 μB). Gas-phase calculations predict that the ground-state and first excited-state multiplet separations are larger for 1Er than 2Er, while the ordering for dysprosium is 1Dy > 2Dy.

show abstract

Homoleptic organolanthanide compounds supported by the bis(dimethylsilyl)benzyl ligand

Cited by 15 publications

References 32 publications

Homoleptic Trivalent Tris(alkyl) Rare Earth Compounds

Homoleptic Trivalent Tris(alkyl) Rare Earth Compounds

Thermally Stable Cationic Bis(benzhydryl) Complexes of Early Lanthanides (La, Ce, Nd)

Structure and Magnetic Properties of Homoleptic Trivalent Tris(alkyl)lanthanides

Contact Info

Product

Resources

About