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TYUKALOVA et al.
are similar to triphenylphosphine ones (i.e., they VII, too, occur through formation of such complexes.
contain two C3-bound ligands or acetylacetonate
anions) but are less active. On the other hand, the low
oxidation rates can also associated with the inactivity
The other complexes ( complex VI) are inactive in
the catalytic oxidation of the phosphine. They are
stable in solutions, and their formation is confirmed
by spectral data.
of
complexes VI partially formed in the first stage.
Attempted oxidation of PC18H13 at 5:1 and 9:1
EXPERIMENTAL
P:Pd ratios in benzene and acetonitrile containing
traces of water and at high reactant concentrations
(CPd 0.04 M), used for registration of IR spectra, gave
results differing from those obtained at 1:1 and 3:1
P:Pd ratios. The IR spectra show (Tables 3 and 4)
that initially the reaction solution contains C3-bound
and chelate forms of the acetylacetonate ligands, but
the amount of both species decreases with time, and
free acetylacetone appears in the solution (more than
50%). This follows from the appearance of three
The UV spectra were recorded on a Specord UV
VIS spectrophotometer in the range 50000
15000 cm . Solutions for spectral measurements
were prepared in picnometers (5 ml in volume) so that
the concentrations of Pd(acac)2 were in the range
0.005 0.001 M.
1
The IR spectra were measured on a Specord M-80
1
spectrometer in the range 4000 200 cm . The con-
centrations of Pd(acac)2 in the working solutions were
0.015 0.045 M.
1
absorption bands, , cm : 1730, 1712, and 1600
1615 (in benzene, a broad band) or 1620 (in aceto-
nitrile). The solution gets dark brown. Here, evidently,
the reduction of Pd(II) to Pd(0) takes place to give a
REFERENCES
zero-valent complex Pd(PC18H13) (VII):
4
1. Ratovskii, G.V., Tyukalova, O.V., Tkach, V.S., and
Shmidt, F.K., Zh. Obshch. Khim., 1996, vol. 66, no. 11,
pp. 1791 1795.
Pd(acac)2 + 5PC18P13 + H2O
Pd(PC18H13)4 + 2acacH + P(O)C18H13.
2. Tyukalova, O.V., Ratovskii, G.V., and Shmidt, F.K.,
Koord. Khim., 1997, vol. 23, no. 4, pp. 288 292.
The zero-valent complex is unstable in the presence
of oxygen and decomposes to phosphine oxide and
brown products. With PPh3, such reduction reaction
proceeds only in an inert atmosphere, while in the
presence of air oxygen the competing process of ca-
talytic oxidation of PPh3 with subsequent regeneration
of complex I and Pd(acac)2 takes place [6]. Evidently,
with PC18H13, at high concentrations and large
excesses of the phosphine, the redox process accord-
ing to above equation is preferred even in the presence
of oxygen. It is known that zero-valent palladium
complexes like VII catalyze oxidation of phosphines.
Probably, complex VII formed in the presence of
oxygen is to a certain extent involved in oxidation of
the phosphine and then decomposes.
3. Ratovskii, G.V., Tyukalova, O.V., Tkach, V.S., and
Shmidt, F.K., Zh. Obshch. Khim., 1996, vol. 66, no. 5,
pp. 708 715.
4. Ratovskii, G.V., Tyukalova, O.V., Tkach, V.S., and
Shmidt, F.K., Zh. Obshch. Khim., 1998, vol. 68, no. 10,
pp. 1660 1668.
5. Davydov, S.N., Rodionov, A.N., Shigorin, D.N., Syut-
kina, O.P., and Krasnova, T.L., Zh. Fiz. Khim., 1980,
vol. 54, no. 2, pp. 506 508.
6. Tyukalova, O.V., Ratovskii, G.V., Belykh, L.B., and
Shmidt, F.K., Zh. Obshch. Khim., 1997, vol. 67, no. 1,
pp. 58 92.
7. Garnovskii, A.D., Sadimenko, A.P., Vasil’chenko, I.S.,
and Garnovskii, D.A., Abstracts of Papers, XIX Vseros-
siiskoe Chuguevskoe soveshchanie po khimii kom-
pleksnykh soedinenii (XIX All-Russia Chuguev Conf.
on Chemistry of Complex Compounds), Ivanovo, 1999,
p. 9.
Hence, 9-phenyl-9-phosphafluorene forms two
types of complexes with Pd(acac)2. The first ones are
analogous to triphenylphosphine complexes I V.
They undergo rearrangements with time and are active
in the catalytic oxidation of the phosphine. The reduc-
tion of Pd(II) to Pd(0) and the formation of complex
8. Nief, F. and Ricard, L., J. Organomet. Chem., 1994,
vol. 464, no. 2, pp. 149 154.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 6 2001
Tyukalova
