925462-56-2Relevant academic research and scientific papers
Trinuclear alkyl hydrido rare-earth complexes supported by amidopyridinato ligands: Synthesis, structures, C-Si bond activation and catalytic activity in ethylene polymerization
Lyubov, Dmitry M.,Cherkasov, Anton V.,Fukin, Georgy K.,Ketkov, Sergey Yu.,Shavyrin, Andrey S.,Trifonov, Alexander A.
, p. 14450 - 14460 (2014)
The reaction of Ap9MeLu(CH2SiMe3)2(thf) (Ap9Me= (2,4,6-trimethylphenyl)[6-(2,4,6-triisopropylphenyl)pyridine-2-yl]amido ligand) with two molar equivalents of PhSiH3affords a trinuclear alkyl-hydrido cluster [(Ap9MeLu)3(μ2-H)3(μ3-H)2(CH2SiMe3)(thf)2]. The analogous reactions with Ap9MeLn(CH2SiMe3)2(thf) (Ln = Y, Yb) are more complex and result in the formation of mixtures of two types of trinuclear alkyl-hydrido complexes [(Ap9MeLn)3(μ2-H)3(μ3-H)2(CH2SiMe3)(thf)2] and [(Ap9MeLn)3(μ2-H)3(μ3-H)2(CH2SiH2Ph)(thf)2] differing in the alkyl group. The DFT calculations of [(ApY)3(μ2-H)3(μ3-H)2(CH2SiMe3)(thf)2] (Ap = (2,6-diisopropylphenyl)[6-(2,4,6-triisopropylphenyl)pyridine-2-yl]amido ligand) confirm localization of the HOMO on the Ap-Y(1A)-CH2SiMe3fragment, thus explaining its enhanced reactivity. Analysis of the electron density distribution reveals the Y-H and H-H bonding interactions in the (Y)3(μ2-H)3(μ3-H)2moiety. The NMR studies of diamagnetic complexes [(Ap9MeLu)3(μ2-H)3(μ3-H)2(CH2SiMe3)(thf)2] and [(ApY)3(μ2-H)3(μ3-H)2(CH2SiMe3)(thf)2] demonstrated that the trinuclear cores are retained in the solution and revealed exchange between μ3- and μ2-bridging hydrido ligands. Complexes [(ApLn)3(μ2-H)3(μ3-H)2(CH2SiMe3)(thf)2], the cationic yttrium hydrido cluster [(ApY)3(μ2-H)3(μ3-H)2(thf)3]+[B(C6F5)4]-as well as [(Ap9MeLn)3(μ2-H)3(μ3-H)2(CH2SiMe3)(thf)2] proved to be active in catalysis of ethylene polymerization under mild conditions.
Scandium, yttrium, and ytterbium bisalkyl complexes stabilized by monoanionic amidopyridinate ligands
Lyubov,Rad’kov, V. Yu.,Cherkasov,Fukin,Trifonov
, p. 2594 - 2600 (2017/05/19)
A reaction of Sc, Y, and Yb amidopyridinate dichlorides with the corresponding amount of LiCH2SiMe3 was used to synthesize bis(trimethylsilylmethyl) complexes (Ap)Ln(CH2SiMe3)2-(THF) (Ap is N-mesityl-6-(2,4,6-triisopropylphenyl)pyridine-2-amide (Ap9Me), Ln = Y (2); Ap is N-(2,6-diisopropylphenyl)-6-(2,4,6-triisopropylphenyl)pyridine-2-amide (Ap*), Ln = Sc (3), Yb (4)). An exchange reaction of yttrium amidopyridinate dichloride derivative 1 with 4 equiv. of ButLi in hexane gave the corresponding di-tert-butyl derivative Ap9MeY(But)2(THF) (5). Molecular structures of complexes 3 and 4 were established by X-ray diffraction. A method of the ligand solid angles was used to calculate the completion degree of the metal atom coordination sphere for the series of isomorphic derivatives (Ap*)Ln(CH2SiMe3)2(THF) containing the central metal ions with different ionic radii (Sc, Y, Yb, Lu). According to this method, the amidopyridinate ligand solid angle in these complexes virtually does not vary, while the solid angles of coordinated THF molecule and alkyl ligands vary within a wide range.
