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Russ.Chem.Bull., Int.Ed., Vol. 61, No. 12, December, 2012
Chimitov et al.
used as the starting compounds. Potassium acetylacetonate was
synthesized according to the procedure described earlier:16 stoꢀ
ichiometric amount of acetylacetone was added dropwise to
a solution of potassium hydroxide in ethanol with heating and
constant stirring; after the reaction reached completion, a pearl
precipitate formed was filtered off using paper filter and dried in
air. According to the IR spectroscopic data and elemental analyꢀ
sis, the product under these conditions is semi hydrated potassiꢀ
um acetylacetonate (Kacac•0.5H2O). Found (%): C, 40.5;
H, 5.6. C5H8O2.5K. Calculated (%): C, 40.8; H, 5.4. Ketoimine
was synthesized according to the known procedure12 by the reꢀ
action of acetylacetone with aqueous solution of ammonia, the
ketoimine formed was extracted with toluene.
The reaction systems were activated on a CEM Explorer 48
MWꢀinstallation (USA), which was a combination of a Discover
Sꢀclass reaction module and automatic sample loadingꢀunloadꢀ
ing module.
The installation was additionally equipped with a digital video
camera for the visual monitoring and video recording reaction
systems in the process of the MWꢀirradiation. The operating
system also contained 10ꢀ and 35ꢀmL vials (miniꢀreactors) to
function at an increased (up to 20 atm) pressure.
pule, which was placed into the reactor of a MWꢀoven, followed
by the addition of excess of ketoimine dissolved in water, and the
mixture was subjected to MWꢀirradiation. After an appropriate
time (see Table 2), the experiment was stopped and the product
was isolated either by filtration, or by extraction with toluene
with subsequent evaporation of the solvent.
Identification of products. Analysis by TLC was carried out
on Silufol plates precoated with SiO2, eluent chloroform—diꢀ
ethyl ether (19 : 1). The comparison compounds were M(acac)3
(M = Rh, Ru) or Pd(iꢀacac)2 obtained by us according to the
procedures developed in the A. V. Nikolaev Institute of Inorganꢀ
ic Chemistry, Siberian Branch of the Russian Academy of Sciꢀ
ences8—11 and subjected to purification by sublimation in vacuum
gradient oven at P = 10–2 Torr and T = 150—180 C. Elemental
analysis was carried out on a Euro EA 3000 CHNꢀanalyzer.
This work was financially supported by the Governꢀ
ment of the Russian Federation (Program of State Supꢀ
port of Scientific Studies Supervised by Leading Scientists
in Russian Educational Institutions of Higher Professional
Education, November 24, 2010, Grant 11.G34.31.0033).
The maximal power of the MWꢀirradiation was 300 W, the
power was regulated with the discreteness of 1 W. An IR sensor
of temperature with the range of measured temperatures up to
300 C was incorporated into the system, the compositions under
study could be magnetically stirred with different intensity, that
increased homogeneity of the MWꢀheating of reaction mixtures.
The system had convenient for users interface, was connectꢀ
ed through a network cable to computer with the Synergy liꢀ
censed software to control the experiment and record the experꢀ
imental data. The simultaneous control of MWꢀpower, temperꢀ
ature, and pressure enabled one to accurately reproduce condiꢀ
tions of the MWꢀreaction in subsequent experiments.
In the case of solidꢀphase systems (see Table 1), a mixture of
solid MCl3•xH2O and Kacac•0.5H2O was placed into an amꢀ
pule with a heatꢀproof stopper and subjected to MWꢀactivaꢀ
tion. After that, the product of the synthesis was extracted with
chloroform.
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Synthesis of M(acac)3 in aqueous solutions (see Table 2, enꢀ
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Received March 23, 2012;
in revised form September 17, 2012