Synthesis and molecular structures of YbII and Ca bis(amidinate) complexes containing the tridentate amidinate ligand [2,6-Pri2C6H3NC(But)NC6H4OMe-2]

Lyubov, Dmitry M.; Basalov, Ivan V.; Cherkasov, Anton V.; Fukin, Georgy K.

doi:10.1007/s11172-018-2092-9

“…The hydride resonance of the major species displays a significant upfield shift (7.52 ppm, 1 J Yb-H = 398 Hz) in comparison to related Yb(II) hydride derivatives such as the (THF)-coordinated, [BDI Dipp YbH(THF)] 2 (9.92 ppm, 1 J Yb-H = 369 Hz) 31 , and the tris(pyrazolyl)borate derivative, [{(Tp tBu,Me ) YbH} 2 ] (Tp tBu,Me = [HB(3-tBu-5-Me-C 3 N 2 ) 3 ] -) (10.5 ppm, 1 J Yb-H = 369 Hz) 34 . The low frequency of this hydride resonance is, however, closely comparable with that of [{[t-BuC(NDipp) 2 ]Yb(μ-H)} 2 ] (7.74 ppm, 1 J Yb-H = 460 Hz), in which the amidinate ligands are bound to each Yb(II) centre via a κ 1 -N,η 6 -Dipp chelate and which display a similar arene interaction 29 . Based on this precedent, therefore, we ascribe the major species observed in the solution spectra of 2 to reflect a similar augmentation of the electron density at Yb and the maintenance of the polyhapto engagement of the aromatic π-system observed in its solid-state structure 35 .…”

Section: Resultsmentioning

confidence: 51%

“…Each Yb(II) centre binds to the β-diketiminato-N atoms and interacts in a η 6 -coordination mode (Yb1-Ar cent 2.7099(9) Å) with a Dipp substituent of a second BDI-Dipp YbH unit of the dimer. The η 6 -coordination of 2 is significantly weaker than in other ytterbium(II) complexes with a Yb(II) κ 1 -N, η 6 -Dipp chelate (2.424-2.520 Å) [28][29][30] , suggesting that the solidstate structure may not be retained in solution. This geometry contrasts significantly with both of the related dimeric (THF)coordinated complexes, [BDI Dipp MH(THF)] 2 (M = Yb or Ca) [31][32][33] , and the solvent-free calcium analogue, [BDI Dipp CaH] 2 6 , in which the μ 2 -hydride ligands provide the sole bridging interactions.…”

Section: Resultsmentioning

confidence: 88%

Hydroarylation of olefins catalysed by a dimeric ytterbium(II) alkyl

Richardson¹,

Douair²,

Cameron³

et al. 2021

Preprint

0

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Although the nucleophilic alkylation of aromatics has recently been achieved with a variety of potent main group reagents, all of this reactivity is limited to a stoichiometric regime. We now report that the ytterbium(II) hydride, [BDI YbH] (BDI = CH[C(CH )NDipp] , Dipp = 2,6-diisopropylphenyl), reacts with ethene and propene to provide the ytterbium(II) n-alkyls, [BDI YbR] (R = Et or Pr), both of which alkylate benzene at room temperature. Density functional theory (DFT) calculations indicate that this latter process operates through the nucleophilic (S 2) displacement of hydride, while the resultant regeneration of [BDI YbH] facilitates further reaction with ethene or propene and enables the direct catalytic (anti-Markovnikov) hydroarylation of both alkenes with a benzene C-H bond. Dipp Dipp Dipp Dipp 2 3 2 2 N 2

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“…The hydride resonance of the major species displays a significant upfield shift (7.52 ppm, 1 J Yb-H = 398 Hz) in comparison to related Yb(II) hydride derivatives such as the (THF)-coordinated, [BDI Dipp YbH(THF)] 2 (9.92 ppm, 1 J Yb-H = 369 Hz) 31 , and the tris(pyrazolyl)borate derivative, [{(Tp tBu,Me ) YbH} 2 ] (Tp tBu,Me = [HB(3-tBu-5-Me-C 3 N 2 ) 3 ] -) (10.5 ppm, 1 J Yb-H = 369 Hz) 34 . The low frequency of this hydride resonance is, however, closely comparable with that of [{[t-BuC(NDipp) 2 ]Yb(μ-H)} 2 ] (7.74 ppm, 1 J Yb-H = 460 Hz), in which the amidinate ligands are bound to each Yb(II) centre via a κ 1 -N,η 6 -Dipp chelate and which display a similar arene interaction 29 . Based on this precedent, therefore, we ascribe the major species observed in the solution spectra of 2 to reflect a similar augmentation of the electron density at Yb and the maintenance of the polyhapto engagement of the aromatic π-system observed in its solid-state structure 35 .…”

Section: Resultsmentioning

confidence: 53%

“…Each Yb(II) centre binds to the β-diketiminato-N atoms and interacts in a η 6 -coordination mode (Yb1-Ar cent 2.7099(9) Å) with a Dipp substituent of a second BDI-Dipp YbH unit of the dimer. The η 6 -coordination of 2 is significantly weaker than in other ytterbium(II) complexes with a Yb(II) κ 1 -N, η 6 -Dipp chelate (2.424-2.520 Å) [28][29][30] , suggesting that the solidstate structure may not be retained in solution. This geometry contrasts significantly with both of the related dimeric (THF)coordinated complexes, [BDI Dipp MH(THF)] 2 (M = Yb or Ca) [31][32][33] , and the solvent-free calcium analogue, [BDI Dipp CaH] 2 6 , in which the μ 2 -hydride ligands provide the sole bridging interactions.…”

Section: Resultsmentioning

confidence: 88%

Hydroarylation of olefins catalysed by a dimeric ytterbium(II) alkyl

Richardson

¹

,

Douair

²

,

Cameron

³

et al. 2021

View full text Add to dashboard Cite

Although the nucleophilic alkylation of aromatics has recently been achieved with a variety of potent main group reagents, all of this reactivity is limited to a stoichiometric regime. We now report that the ytterbium(II) hydride, [BDIDippYbH]2 (BDIDipp = CH[C(CH3)NDipp]2, Dipp = 2,6-diisopropylphenyl), reacts with ethene and propene to provide the ytterbium(II) n-alkyls, [BDIDippYbR]2 (R = Et or Pr), both of which alkylate benzene at room temperature. Density functional theory (DFT) calculations indicate that this latter process operates through the nucleophilic (SN2) displacement of hydride, while the resultant regeneration of [BDIDippYbH]2 facilitates further reaction with ethene or propene and enables the direct catalytic (anti-Markovnikov) hydroarylation of both alkenes with a benzene C-H bond.

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