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Issue 38, 2014
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Trinuclear alkyl hydrido rare-earth complexes supported by amidopyridinato ligands: synthesis, structures, C–Si bond activation and catalytic activity in ethylene polymerization

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Abstract

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 PhSiH3 affords a trinuclear alkyl-hydrido cluster [(Ap9MeLu)32-H)33-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)32-H)33-H)2(CH2SiMe3)(thf)2] and [(Ap9MeLn)32-H)33-H)2(CH2SiH2Ph)(thf)2] differing in the alkyl group. The DFT calculations of [(Ap*Y)32-H)33-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)32-H)33-H)2 moiety. The NMR studies of diamagnetic complexes [(Ap9MeLu)32-H)33-H)2(CH2SiMe3)(thf)2] and [(Ap*Y)32-H)33-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 [(Ap*Ln)32-H)33-H)2(CH2SiMe3)(thf)2], the cationic yttrium hydrido cluster [(Ap*Y)32-H)33-H)2(thf)3]+[B(C6F5)4] as well as [(Ap9MeLn)32-H)33-H)2(CH2SiMe3)(thf)2] proved to be active in catalysis of ethylene polymerization under mild conditions.

Graphical abstract: Trinuclear alkyl hydrido rare-earth complexes supported by amidopyridinato ligands: synthesis, structures, C–Si bond activation and catalytic activity in ethylene polymerization

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Publication details

The article was received on 18 Mar 2014, accepted on 04 Jun 2014 and first published on 13 Jun 2014


Article type: Paper
DOI: 10.1039/C4DT00806E
Citation: Dalton Trans., 2014,43, 14450-14460
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    Trinuclear alkyl hydrido rare-earth complexes supported by amidopyridinato ligands: synthesis, structures, C–Si bond activation and catalytic activity in ethylene polymerization

    D. M. Lyubov, A. V. Cherkasov, G. K. Fukin, S. Yu. Ketkov, A. S. Shavyrin and A. A. Trifonov, Dalton Trans., 2014, 43, 14450
    DOI: 10.1039/C4DT00806E

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