800
TORUBAEV et al.
On the other hand, the presence of lone electron
IR (hexane, cm–1): 2080 s (CO), 2040 s (CO), 2025
pairs on the Te atom makes ArTeX promising nucleo- s (CO).
philic reagents. That is why it was interesting to study
X-ray diffraction analysis. Selected crystallo-
the behavior of PhTeI in reactions with electron-defi-
cient carbonyl complexes of transition metals (e.g.,
iron).
graphic parameters and a summary of data collection
and refinement for structures I and II are given in
Table 1. Both structures were solved by the direct
method and refined by the least-squares method on F2
in the anisotropic (for H atoms, isotropic) approxima-
tion with the SHELXTL program package [12]. The
hydrogen atoms were located geometrically. Selected
bond lengths and angles in structures I and II are given
in Table 2. Atomic coordinates and other structural
parameters of complexes I and II have been deposited
with the Cambridge Crystallographic Data Center
(CCDC nos. 687773 (I) and 687774 (II); see
http://www.ccdc.cam.ac.uk/data_request/cif).
EXPERIMENTAL
All manipulations dealing with the synthesis and
isolation of the complexes were carried out under pure
argon in dehydrated solvents. IR spectra were recorded
on a Specord 75IR spectrophotometer for pellets with
KBr and solutions in hexane.
Synthesis of (CO)3FeI2(Ph2Te2) (I). Iodine (0.12 g,
0.5 mmol) was added at 0°C (ice bath) to a magnetically
stirred orange solution of Ph2Te2 (0.20 g, 0.5 mmol) in
diethyl ether (30 ml). The resulting black red mixture
was stirred at 0°C for 10 min and then Fe(CO)5 (0.14 ml,
1 mmol) was added in one portion. The reaction mix-
ture promptly turned dark red. Stirring was continued
for an additional 30 min, while slowly warming the
mixture to ambient temperature. Then the solution was
concentrated in a water aspirator vacuum until it
became turbid and kept at –10°ë for 12 h. A dark red
crystalline precipitate formed. The yield was 0.25 g
(30%).
RESULTS AND DISCUSSION
A direct reaction of the tetramer [PhTeI]4 with
Fe(CO)5 gave dark red crystalline monomeric complex
I. In the complex, the diphenyl ditelluride molecule is
bound to cis-tricarbonyldiiodoiron:
Te
Te
For C15H10FeI2O3Te2 (M = 803.10)
Fe(CO)5 + PhTel
0°C, Et2O
anal. calcd (%):
Found (%):
C, 22.43;
C, 21.49;
H, 1.26.
H, 1.27.
OC
OC
I
I
Fe
IR (KBr, cm–1): 2080 s, 2040 s, 2025 s, 710 s, 670 m,
580 m.
CO
(I)
Synthesis of (CO)3FeI2(PhTeI) (II). Iodine (0.19 g,
~0.75 mmol) was added at 0°C (ice bath) to a magneti-
cally stirred orange solution of Ph2Te2 (0.1 g,
0.25 mmol) in diethyl ether (30 ml). The mixture was
stirred for 30 min, while warming it to ambient temper-
ature. A solution of Fe(CO)5 (0.07 ml, ~0.5 mmol) in
ether (10 ml) was added dropwise to the dark red mix-
ture containing a red precipitate of PhTeI3. The color of
the reaction mixture deepened and the precipitate dis-
solved almost completely within an hour. Then the
reaction mixture was evaporated to dryness in a water
aspirator vacuum and the residue was dissolved in ether
(20 ml). The solution was filtered and concentrated
with hexane (10 ml) in a water aspirator vacuum to
slight turbidity. The concentrate was kept at –10°ë for
12 h. The black crystalline precipitate that formed was
filtered off, washed with hexane, and dried in vacuo.
The yield of solvate II · C6H14 was 0.15 g (36%).
According to X-ray diffraction data (Fig. 1), the
Fe−Te distance in complex I (2.5724(6) Å) is apprecia-
bly shorter than the sum of the covalent Fe and Te radii
(1.34 + 1.37 = 2.71 Å) and the Te–Te bond
(2.7705(5) Å) is only slightly longer than that in free
Ph2Te2 (2.705(1) Å). Similar bond characteristics have
been reported in [13] for a mononuclear complex of
diphenyl ditelluride with Cr(CO)5 (Cr–Te 2.679(3) Å,
Te–Te 2.737 Å). However, the torsion angle CTeTeC in
complex I is 60.26° (in Cr(CO)5(Ph2Te2), this angle is
97.19°). The intermolecular contacts Te···I and í···íÂ
in structure I (3.668 and 3.800 Å, respectively) do not
affect the geometry of the diphenyl ditelluride ligand,
although they are responsible for the crystal packing in
which the molecules of complex I are united into chains
composed of dimeric units (Fig. 2). Since the Te–Te
contact is already substantial in the starting tetramer
(PhTeI)4, the complexation involves only its decompo-
sition into two fragments (PhTeI)2 and transfer of two
iodine atoms to the Fe atom.
For C15H19FeI3O3Te (M = 811.47)
anal. calcd (%):
Found (%):
C, 22.12;
C, 22.46;
H, 2.35.
H, 0.93.
Nevertheless, complex II with PhTeI as a ligand was
obtained in a reaction of Fe(CO)5 with PhTeI3:
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 34 No. 11 2008
Torubaev
