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Rare-earth dichloro and bis(alkyl) complexes supported by bulky amidoimino ligand. Synthesis, structure, reactivity and catalytic activity in isoprene polymerizationElectronic supplementary information (ESI) available. CCDC 915562915569. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c3dt33108c
A monoanionic amidoimino ligand system [(2,6- i Pr 2 C 6 H 3 )N&z.dbd;C(Me)C(&z.dbd;CH 2 )N(C 6 H 3 -2,6- i Pr 2 )] was successfully employed for the synthesis of monomeric dichloro [(2,6- i Pr 2 C 6 H 3 )N&z.dbd;C(Me)C(&z.dbd;CH 2 )N(C 6 H 3 -2,6- i Pr 2 )]LnCl 2 (THF) 2 (Ln = Y, 2Y...
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| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Online Access: | Get full text |
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| Summary: | A monoanionic amidoimino ligand system [(2,6-
i
Pr
2
C
6
H
3
)N&z.dbd;C(Me)C(&z.dbd;CH
2
)N(C
6
H
3
-2,6-
i
Pr
2
)]
was successfully employed for the synthesis of monomeric dichloro [(2,6-
i
Pr
2
C
6
H
3
)N&z.dbd;C(Me)C(&z.dbd;CH
2
)N(C
6
H
3
-2,6-
i
Pr
2
)]LnCl
2
(THF)
2
(Ln = Y,
2Y
; Lu,
2Lu
) and bis(alkyl) [(2,6-
i
Pr
2
C
6
H
3
)N&z.dbd;C(Me)C(&z.dbd;CH
2
)N(C
6
H
3
-2,6-
i
Pr
2
)]Ln(CH
2
SiMe
3
)
2
(THF) (Ln = Y,
4Y
; Lu,
4Lu
) species of yttrium and lutetium. Dichloro complexes
2Y
and
2Lu
turned out to be unstable in aromatic solvents. The ligand symmetrization reaction in the case of
2Y
affords the yttrium complex coordinated by dianionic [(2,6-
i
Pr
2
C
6
H
3
)NC(&z.dbd;CH
2
)C(&z.dbd;CH
2
)N(C
6
H
3
-2,6-
i
Pr
2
)]
2
ligand, (2,6-
i
Pr
2
C
6
H
3
)N&z.dbd;C(Me)C(Me)&z.dbd;N(C
6
H
3
-2,6-
i
Pr
2
) and YCl
3
. On the contrary, bis(alkyl) species
4Y
and
4Lu
are rather stable and do not undergo such a transformation or thermal decomposition. The treatment of complex
4Y
with DME resulted in CO bond cleavage and the formation of a dimeric methoxy-alkyl species {[(2,6-
i
Pr
2
C
6
H
3
)N&z.dbd;C(Me)C(&z.dbd;CH
2
)N(C
6
H
3
-2,6-
i
Pr
2
)]Y(CH
2
SiMe
3
)(-OMe)}
2
(
5
). The ternary systems
4Ln
/Al
i
Bu
3
/borate (borate = [HNMe
2
Ph][B(C
6
F
5
)
4
] and [CPh
3
][B(C
6
F
5
)
4
]; molar ratio 1:10:1) performed high catalytic activity in isoprene polymerization and ability to convert into polymer 10005000 equivalents of isoprene in 20120 min with quantitative conversion. The obtained polyisoprenes possessed high molecular weights (2.9 10
4
4.1 10
4
) and moderate polydispersities (2.143.52). Predominant 3,4-regioselectivity (up to 78%) was observed.
LLn(CH
2
SiMe
3
)
2
(THF) + AliBu
3
+ borane (1:10:1) efficient catalytic systems for isoprene polymerization. |
|---|---|
| ISSN: | 1477-9226 1477-9234 |
| DOI: | 10.1039/c3dt33108c |