1592
Russ.Chem.Bull., Int.Ed., Vol. 51, No. 8, August, 2002
Magdesieva et al.
Table 2. Potentials of the oxidation (E Ox) and reduction (ERed
)
References
2
peaks in the CV curves for complexes 1, η ꢀC60Pd(dppf),
and some structures similar to the fragments in complex 1
(graphite electrode, оꢀdichlorobenzene, 0.15 М Bun4NBF4,
Ag/AgCl/KCl)
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Compound
E Ox
ERed
V
3. Q. Xie, F. Arias, and L. J. Echegoyen, J. Am. Chem. Soc.,
1993, 115, 9818.
2
η ꢀC60Pd(dppf)
1
0.87, 1.22
–0.69, –1.04, –1.52
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5. T. J. Colacot, Platinum Metals Review, 2001, 45, 22.
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Sokolov, and K. P. Butin, Elektrokhimiya, 1999, 35, 1125
[Russ. J. Electrochem., 1999, 35 (Engl. Transl.)].
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42, 392 (Engl. Transl.)].
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13. C. Amatore, A. Jutand, M. J. Medeiros, and L. Mottier,
J. Electroanal. Chem. 1997, 422, 125.
14. T. V. Magdesieva, V. V. Bashilov, D. N. Kravchuk, P. V.
Petrovskii, V. I. Sokolov, and K. P. Butin, in Recent Adꢀ
vances in the Chemistry and Physics of Fullerenes, Eds. R. S.
Ruoff and K. M. Kadish, The Electrochemical Society,
Pennington, 1998, 1322.
15. S. P. Gubin, L. I. Denisovich, N. V. Zakurin, and A. G.
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16. A. P. Tomilov, I. N. Chernykh, and Yu. M. Chernykh, in
Elektrokhimiya elementoorganicheskikh soedinenii. Elementy
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(in Russian).
1.03, 1.44, 1.62 –0.43, –0.80, –1.25
CymPPh2
[(Ph2Pꢀη ꢀC5H4)]2Fe
CpMn(CO)3
Cp2Fe 16
1.47
0.97
0.87
0.45
—
—
–2.19
–2.93
5
15
than in the case of the cymanthrenyl complex (see
Table 2). The palladium bridge in cymanthrenyl comꢀ
plex 1 is localized between two strong electronꢀwithꢀ
drawing fragments, viz., С60 and CymPPh2. Therefore,
comparison of the reduction potentials for the exohedral
complexes shows that charge transfer from the Pd atom
to fullerene in the complex 1 is less significant than that
2
in the η ꢀC60Pd(dppf) complex.
2
In the case of η ꢀC60Pd(dppf), the second redox tranꢀ
sition observed in the anodic potential region corresponds
to the electron transfer from the MO, whose formation
is mainly contributed from the orbitals in the Fe atom.7
The oxidation of the Mn atom is more difficult than the
FeII/FeIII transition in ferrocene (see Table 2). Thereꢀ
fore, analyzing the oxidation of complex 1, we have to
take into account two possibilities, namely, oxidation
involving the AO of Mn and the AO of P. The data of
quantumꢀchemical calculations (see above) indicate that
the second redox transition is mainly localized on the
orbitals mainly formed by the orbitals of the P atom.
Perhaps, the electronꢀwithdrawing CO groups in the
molecule lower the orbitals of Mn, and the orbital localꢀ
ized on the P atom becomes HOMOꢀ1.
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 01ꢀ03ꢀ
33147), the Scientific Technical Programs "Fullerenes
and Atomic Clusters" and "Fundamental Problems of
Modern Chemistry," and the Program of the Presidium
of the Russian Academy of Sciences "Lowꢀdimensional
Quantum Structures."
Received December 4, 2001;
in revised form March 4, 2002