Trinuclear alkyl hydrido rare-earth complexes supported by amidopyridinato ligands: synthesis, structures, C-Si bond activation and catalytic activity in ethylene polymerization.
Dalton Trans
; 43(38): 14450-60, 2014 Oct 14.
Article
en En
| MEDLINE
| ID: mdl-24983231
The reaction of Ap(9Me)Lu(CH2SiMe3)2(thf) (Ap(9Me) = (2,4,6-trimethylphenyl)[6-(2,4,6-triisopropylphenyl)pyridine-2-yl]amido ligand) with two molar equivalents of PhSiH3 affords a trinuclear alkyl-hydrido cluster [(Ap(9Me)Lu)3(µ(2)-H)3(µ(3)-H)2(CH2SiMe3)(thf)2]. The analogous reactions with Ap(9Me)Ln(CH2SiMe3)2(thf) (Ln = Y, Yb) are more complex and result in the formation of mixtures of two types of trinuclear alkyl-hydrido complexes [(Ap(9Me)Ln)3(µ(2)-H)3(µ(3)-H)2(CH2SiMe3)(thf)2] and [(Ap(9Me)Ln)3(µ(2)-H)3(µ(3)-H)2(CH2SiH2Ph)(thf)2] differing in the alkyl group. The DFT calculations of [(Ap*Y)3(µ(2)-H)3(µ(3)-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)-CH2SiMe3 fragment, thus explaining its enhanced reactivity. Analysis of the electron density distribution reveals the Y-H and H-H bonding interactions in the (Y)3(µ(2)-H)3(µ(3)-H)2 moiety. The NMR studies of diamagnetic complexes [(Ap(9Me)Lu)3(µ(2)-H)3(µ(3)-H)2(CH2SiMe3)(thf)2] and [(Ap*Y)3(µ(2)-H)3(µ(3)-H)2(CH2SiMe3)(thf)2] demonstrated that the trinuclear cores are retained in the solution and revealed exchange between µ(3)- and µ(2)-bridging hydrido ligands. Complexes [(Ap*Ln)3(µ(2)-H)3(µ(3)-H)2(CH2SiMe3)(thf)2], the cationic yttrium hydrido cluster [(Ap*Y)3(µ(2)-H)3(µ(3)-H)2(thf)3](+)[B(C6F5)4](-) as well as [(Ap(9Me)Ln)3(µ(2)-H)3(µ(3)-H)2(CH2SiMe3)(thf)2] proved to be active in catalysis of ethylene polymerization under mild conditions.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Dalton Trans
Asunto de la revista:
QUIMICA
Año:
2014
Tipo del documento:
Article
País de afiliación:
Rusia
Pais de publicación:
Reino Unido