Russian Chemical Bulletin, International Edition, Vol. 53, No. 2, pp. 481—482, February, 2004
481
Letters to the Editor
Formation of dibenzenevanadium by the reaction of
dysprosium diiodide with vanadocene in benzene
M. N. Bochkarev,ꢀ M. E. Burin, and V. K. Cherkasov
G. A. Razuvaev Institute of Organometallic Chemistry of the Russian Academy of Sciences,
4
9 ul. Tropinina, 603950 Nizhny Novgorod, Russian Federation.
Fax: +7 (831 2) 12 7497. Eꢀmail: mboch@imoc.sinn.ru
1
Recently, we have found that diiodides DyI (1) and
system
analogous
to
the
Fischer
system
2
2
NdI possessing strong reducing properties can successꢀ
(Al—AlCl —VCl —C H ) failed. An attempt to use comꢀ
2
3 4 6 6
fully be used as an alternative to alkali metals in the synꢀ
thesis of vanadocene (2) and cobaltocene. As part of our
continuing investigations of the properties of these salts,
in the present study we demonstrated that diiodide 1 can
also be used for the preparation of dibenzenevanadium (3).
Heating of a mixture of 1 and 2 in benzene at 85 °C was
accompanied by a gradual change in the color of the
solution from violet to redꢀbrown. After separation of the
precipitate and removal of benzene in vacuo, we obtained
a solid darkꢀbrown substance. The major portion of this
substance is soluble in hexane. Study by ESR spectroꢀ
scopy demonstrated that only traces of 2 were present in
the hexane solution. However, heating of a brown crystalꢀ
line substance, which was obtained after removal of hexꢀ
ane, in vacuo to 60 °C led to sublimation of compound 2
in an amount of >35% of that introduced into the reacꢀ
tion. Upon further heating of the residue to 110 °C, comꢀ
pound 3 was sublimed in a yield of 15% with respect to the
amount of compound 2 used in the reaction. In benzene,
pound 2 instead of VCl under these conditions was also
unsuccessful.
3
The aboveꢀdescribed reaction is unsuitable for
preparative purposes because of a low yield of the
product. However, the results of the present study are
of basic importance, because they demonstrated that
the reactions of "new" diiodides of divalent lanꢀ
thanides (Nd, Dy, and Tm) with substrates can be carried
3
out not only in solvating ethereal solutions but also in
benzene.
The synthesis and isolation of compound 3 were carried out
under conditions precluding exposure to atmosphere. Diiodide 1
(97%) was purchased from SINOR (Nizhny Novgorod, Russia).
A solution of compound 2 (0.265 g, 1.46 mmol) in benzene
(10 mL) was added to a powder of 1 (1.224 g, 2.94 mmol) at
∼
20 °C. The reaction mixture was heated with stirring to 85 °C
for 10 h. The solution was separated from the precipitate, the
benzene was removed in vacuo, and the residue was extracted
with hexane (2×10 mL). The extract was placed into a sublimaꢀ
tion apparatus, the solvent was removed at room temperature,
and the residue was heated in vacuo by gradually raising the
temperature to 110 °C. A mixture of violet and brown crystals in
a receiver was subjected to repeated sublimation. At 50—60 °C,
diiodide 1 readily reacts with VCl , but this reaction reꢀ
4
sults only in reduction of the latter to VCl . An attempt to
3
synthesize compound 3 in the Dy—DyI —VCl —C H
6
3
4
6
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, p. 459, February, 2004.
066ꢀ5285/04/5302ꢀ0481 © 2004 Plenum Publishing Corporation
1
Bochkarev
