ISSN 1070-3632, Russian Journal of General Chemistry, 2007, Vol. 77, No. 4, p. 648.
Pleiades Publishing, Ltd., 2007.
Original Russian Text
V.S. Tkach, D.S. Suslov, A.V. Rokhin, F.K. Shmidt, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77, No. 4, p. 694.
LETTERS
TO THE EDITOR
Selective Dimerization of Styrene in the Presence of Catalysts
of the Type [(Acac)Pd(PR3)2]BF4 + nBF3 OEt2
V. S. Tkach, D. S. Suslov, A. V. Rokhin, and F. K. Shmidt
Irkutsk State University,
ul. K. Marksa 1, Irkutsk, 664003 Russia
e-mail: tkach_vs@bk.ru
Received October 2, 2006
DOI: 10.1134/S107036320704024X
We have developed a simple method for preparing
cationic palladium complexes [(Acac)Pd(PR3)2]BF4
(I) starting from Pd(Acac)2, PR3, and BF3 OEt2 by
the following general equation: Pd(Acac)2 + 2PR3 +
palladium analogs [1 4] and reaches 153000 mol of
styrene per g-atom of Pd in 7 h, with up to 91% con-
tent of dimers and up to 9% content of trimers.
The NMR spectra were recorded on a Varian VXR-
500S spectrometer, solvent (CD3)2CO. Ampules were
filled in an argon atmosphere. Benzene was dehy-
drated by the standard procedure [5]. Argon was
thoroughly dried and deoxygenated according to [6].
Styrene dimers (100% 1,3-diphenyl-1-butene) were
separated by vacuum distillation; the cis/trans ratio,
2BF3 OEt2
[(Acac)Pd(PR3)2]BF4 + 2OEt2 +
BF2Acac (Acac is acetylacetonate; R = phenyl, o-tol-
yl, or p-tolyl).
Below we give as example the synthesis protocol
for [(Acac)Pd(PPh3)2]BF4 (II). A three-necked flask
was successively charged at 20 C in an argon atmos-
phere with 1.641 mmol of bis(acetylacetonato)palla-
dium, 3.282 mol of triphenylphosphine, and 40 ml of
benzene. Then 3.282 mmol of BF3 OEt2 was added
dropwise with vigorous stirring. A light yellow pre-
cipitate formed; it was filtered off, washed with ben-
zene, and dried in a vacuum (10 mm Hg, 2 h, 20 C).
Yield 91%, mp 174 176 C. Found, %: C 61.2; H
4.24; B 1.1; F 8.25; O 3.92; P 7.1; Pd 12.8. PdC41
H37O2P2BF4. Calculated, %: C 60.3; H 4.53; B 1.35;
1
according to H NMR, was 95/5.
REFERENCES
1. French Patent 2193803, 1974, Chem. Abstr., 1975,
vol. 82, no. 8, 44004b.
2. Jiang, Z. and Sen, A., Organometallics, 1993, vol. 12,
no. 4, p. 1406.
3. Jiajian Peng, Jiayun Li, Huayu Qiu, Jianxiong Jiang,
Kezhi Jiang, Jianjiang Mao, and Guoqiao Lai, J. Mol.
Catal. A: Chem., 2006, vol. 255, nos. 1 2, p. 16.
1
F 9.3; O 3.92; P 7.6; Pd 13.0. NMR spectra: H, ,
ppm: 1.5 (CH3), 5.6 (CH), 7.2 7.8 (CH arom.); 13C,
C, ppm: 27.5 (CH3), 102.3 (CH), 128 136 (arom.),
188.4 (C=O); 19F, F, ppm: 146.1 (BF4); 11B,
ppm: 0.56 (BF4); 31P, P, ppm: 36 (PPh3).
,
4. Myagmarsuren, G., Tkach, V.S., Shmidt, F.K., Me-
syef, M., and Suslov, D.S., J. Mol. Catal. A: Chem.,
2005, vol. 235, nos. 1 2, p. 154.
B
The other cationic complexes of type I (R = o-tol-
yl, p-tolyl) were prepared and characterized similarly.
5. Gordon, A.J. and Ford, R.A., The Chemist’s Com-
panion. A Handbook of Practical Data, Techniques,
and References, New York: Wiley, 1972.
We examined the dimerization of styrene in the
presence of catalytic systems [(Acac)Pd(PR3)2]BF4
BF3 OEt2. Under optimal reaction conditions (B/Pd
8, 75 C, R = Ph), the conversion of styrene into the
target products exceeds that attained on the known
6. Rapoport, F.M. and Il’inskaya, A.A., Laboratornye
metody polucheniya chistykh gazov (Laboratory
Methods for Preparing Pure Gases), Moscow: Izd.
Khimicheskoi Literatury, 1963.
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Tkach
