Article
Li et al.
and L1J were reacted with PdCl2, rufous precipitates were ob-
tained. But these material could not be easy characterized due to
its insolubility in most solvents tested (water, methanol, methy-
lene chloride, DMSO).
cenylimine were designed and prepared from ferrocenyl-
imine ligands with hydrophilic functional group. These
catalysts could effectively catalyze Suzuki cross-coupling
reaction of aryl bromide and phenylboronic acid in neat
water. Although catalyst (C2D) exhibited high activity, re-
cycling of catalyst could not be proceeded because that a
large amount of palladium black precipitates were formed
after reaction at experiment condition, which indicates that
the C2D was sensitive to temperature in water. For C2D-
H2O-C2H5OH catalytic system, not only higher yields of
coupling products with a wide range of substrates could be
obtained at ambient, but also 6 times recycling could be
achieved, in which suggested that the recylablity of the cat-
alyst C2D for Suzuki coupling reaction was determined by
solvent and temperature.
Compound C1D: rust solid; m.p.: >200 oC. IR (KBr): 2932,
1583, 1402, 1190, 1136, 1021, 836 cm-1; MS: 992 [M+H]+. Com-
pound C1J: rust solid; m.p.: >200 oC. IR (KBr): 3002, 1639, 1379,
1138, 1121, 1025, 879, 796, 701 cm-1; MS: 992 [M+H]+. Com-
pound C2D: Atropurpureus Solid; m.p. >250 °C. IR (KBr): 2920,
1579, 1400, 1187, 1126, 1008, 833 cm-1; 1H NMR (DMSO-d6, 400
MHz): d 8.40 (s, 2H), 7.60, 7.58 (d, J = 8.0 Hz, 4H), 7.09, 7.07 (d,
J = 8.4 Hz, 4H), 4.82 (d, J = 1.2 Hz, 2H), 4.54 (s, 2H), 4.43, 4.40
(d, J = 12.9 Hz, 2H), 4.28 (s, 10H); MS: 1080 [M+H2O]. Com-
pound C2J: Atropurpureus Solid; m.p. >250 °C. IR (KBr): 2943,
1546, 1385, 1174, 1109, 1001, 815 cm-1; MS: 1080 [M+H2O].
General procedure for the Suzuki coupling reaction of aryl
bromides with phenyl boronic acid. Aryl bromides (0.5 mmol),
phenylboronic acid (0.75 mmol), Base (1 mmol), PEG 2000 (0.5
mmol), catalyst C2D (0.5 mol %) and H2O (3.0 mL) were stirred 4
h at 60 °C, Or Aryl bromides (0.5 mmol), PhB(OH)2 (0.75 mmol),
NaOH (1.0 mmol), C2D (0.1% mol) and CH3CH2OH/H2O (2:1) (3
mL) were stirred 1 h at room temperature. The reaction mixture
was stirred to complete reaction, and then diluted with water and
ethyl acetate. The organic layer was separated and the aqueous
layer was extracted with ethyl acetate for three times. The com-
bined organic phase was dried with MgSO4, filtrate, solvent was
removed on a rotary evaporator, and the product was isolated by
thin layer chromatography. The purified products were identified
ACKNOWLEDGMENTS
We are grateful to the National Natural Science Foun-
dation of China (No. 20973157) and the Innovation Fund
for Graduate student of Zhengzhou University (No.
2013xjxm020) for their financial support.
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CONCLUSION
A series of new water-soluble cyclopalladated ferro-
402
© 2014 The Chemical Society Located in Taipei & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
J. Chin. Chem. Soc. 2014, 61, 397-403