atmosphere, thus avoiding catalyst oxidation. Finally, it is known
that guanidinium ions have the ability to form complexes with
2 E. G. Kuntz, CHEMTECH, 1987, 17, 570.
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4 (a) P. B. Webb, M. F. Sellin, T. E. Kunene, S. Williamson,
A. M. Z. Slawin and D. J. Cole-Hamilton, J. Am. Chem. Soc.,
3
13
transition metal ions. The guanidinium component of PGMIL
may coordinate with the Rh catalyst in the hydroformylation
reaction, while the polyether tail of PGMIL has large steric
hindrance. The synergy of these two features effectively prevents
the formation of inactive Rh cluster species, thus stabilizing
the Rh catalyst and improving catalytic properties.
2003, 125, 15577; (b) C. P. Mehner, R. A. Cook, N. C. Dispenziere
and E. J. Mozeleski, Polyhedron, 2004, 23, 2679.
5
(a) C. C. Brasse, U. Englert, A. Salzer, H. Waffenschmidt and
P. Wasserscheid, Organometallics, 2000, 19, 3818; (b) F. Favre,
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P. Machnitzki, K. W. Kottsieper and O. Stelzer, Chem. Commun.,
In conclusion, synthesis of ILs with customized functionalized
cations or anions is a more straightforward and effective means
for immobilizing the Rh catalyst in hydroformylation reaction.
Our PGMIL combines the structural benefit of both guanidinium
salt and polyether. The resulting biphasic catalytic system showed
super long-term high activity, selectivity and very low loss of Rh or
P in the hydroformylation of higher alkenes. The turnover number
2
001, 451; (d) R. P. J. Bronger, S. M. Silva, P. C. J. Kamer and
P. W. M. N. van Leeuwen, Chem. Commun., 2002, 3044; (e) D. J.
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8
F. Kong, J. Jiang and Z. Jin, Catal. Lett., 2004, 96, 63.
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(TON) reached as high as 31 188 after thirty-five consecutive runs.
We foresee that PGMIL can also be used in other catalyzed
reactions in ILs and further research is currently underway.
We gratefully acknowledge the financial support from National
Natural Science Foundation of China (No.20976086) and Found-
ation of Key Laboratory of Oil & Gas Fine Chemicals, Ministry of
Education, China (No. XJDX0908-2010-01).
9 P. Wasserscheid, R. van Hal and A. Bo
, 400.
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1 (a) R. P. J. Bronger, S. M. Silva, P. C. J. Kamer and P. W. M.
N. van Leeuwen, Dalton Trans., 2004, 1590; (b) A. Castellanos-
´ ´
Paez, S. Castillon, C. Claver, P. W. M. N. van Leeuwen and
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4
1
1
3
W. G. J. Lange, Organometallics, 1998, 17, 2543.
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1
Notes and references
1
C. D. Frohning and C. W. Kohlpainter, in Applied Homogeneous
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W. A. Herrmann, Wiley-VCH, Weinheim, 1st edn, 1996, p. 29.
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(b) J. Huang, T. Jiang, H. Gao, B. Han, Z. Liu, W. Wu, Y. Chang
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This journal is c The Royal Society of Chemistry 2012
Chem. Commun., 2012, 48, 9017–9019 9019