1070-4272/05/7804-0559 C 2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 4, 2005, pp. 559!564. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005,
Original Russian Text Copyright + 2005 by Kuz’min, Borovkov, Kolker, Brazhyunas.
AND CORROSION PROTECTION OF METALS
Synthesis of Metallofullerenes by Electric-Arc Method
with a Surface-Modified Electrode
S. M. Kuz’min, N. Yu. Borovkov, A. M. Kolker, and V. L. Brazhyunas
Institute of Chemistry of Solutions, Russian Academy of Sciences, Ivanovo, Russia
Ivanovo State University of Chemical Technology, Ivanovo, Russia
Received September 30, 2004; in final form, February 2005
Abstract-A method for synthesis of metallofullerenes by electric-arc sputtering of graphite, in which lan-
thanum compounds are deposited on the surface of a graphite electrode, was suggested. The influence exerted
by the amount of deposited lanthanum on the yield of lanthanum was studied.
At present, endohedral complexes of fullerenes 
and higher fullerenes attract researchers’ attention as
potential objects of nanotechnologies , which pos-
sess nonlinear optical characteristics  and unique
physicochemical properties . Synthesis and identi-
fication of new forms of endofullerenes (various iso-
mers, bi- and trinuclear complexes in encapsulation
of the whole variety of the available elements in the
void in the fullerene molecule) have been extensively
studied . The known methods for synthesis of
metallofullerenes consist in bombardment of a ful-
lerene-containing substrate with metal ions  or
in evaporation of a metal3carbon composite in the
atmosphere of an inert gas . The composites
are evaporated with lasers [21, 22] or by electric-arc
sputtering [16, 22, 23].
Commonly, the composite is prepared as follows.
A hole bored in a graphite rod is filled with a mixture
of a metal oxide, powdered graphite, and binder res-
ins. Then the rod (electrode) is annealed in a vacuum
at a temperature of about 2000oC. As a result, the
carbide of the starting metal is formed and fixed in
the bulk of the electrode.
It should be noted that C
are formed in
synthesis of metallofullerenes. There is evidence [16,
21, 23] that the amount of a metal oxide introduced
into the electrode affects the total yield of fullerenes.
The ratio of yields of hollow fullerenes and metallo-
fullerenes [16, 21, 24] suggests that the formation of
an endocomplex is, in fact, the side process in syn-
thesis of hollow fullerenes.
Use of a combined electrode results in that metal
atoms are introduced into the discharge zone in sput-
tering of the electrode. Having a low ionization po-
tential, metal atoms markedly change the discharge
parameters, and, primarily, make lower the tempera-
ture of electrons in the arc and of the gas . Using
a combined electrode, as a rule, leads to a decrease
in the yield of fullerenes [16, 25, 26].
The yield of metallofullerenes in synthesis is low
and the procedure for preparing a composite is pro-
longed and complicated. This results in that the prob-
lem of obtaining industrial samples of metallofuller-
enes remains unsolved. The efficiency of synthesis
of metallofullerenes is raised by varying the compos-
ition of the composite  and by improving the de-
sign of the reactors used for this purpose .
The aim of this study was to examine specific
features of synthesis of metallofullerenes with a sur-
The experimental installation for synthesis of ful-
lerenes by electric-arc sputtering of graphite is shown
schematically in Fig. 1. A combined electrode was
fabricated from 10-cm-long rectangular graphite rods
with a cross-section of 204to406 mm. The elec-
trode was prepared by depositing an aqueous suspen-
sion of lanthanum carbonate on its surface. The de-
posited layer was dried in air to constant mass and
then the electrode mounted into the reactor was an-