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E. Faoro et al. / Journal of Organometallic Chemistry 691 (2006) 5867–5872
drugs for a wide range of diseases [4–6]; on the other side,
iodine-125 and iodine-131 are very important in the radio-
therapy, as well as radioactive tracers in diagnostic tech-
niques of nuclear medicine [7].
system was stirred for 2 h and a red precipitate of (PyH)-
[mesTeI2] [1] was formed. At this point the addition of
two and five equivalents of I2 (0.6 and 1.5 mmol) leads to
the formation of 2 and 3, respectively. After 1/2 h stirring
the products (red precipitates) were filtered and dissolved
in CH2Cl2. Monocrystals of 2 and 3 were obtained by
recrystallization in CH2Cl2 at ꢀ18 ꢁC.
If the reaction milieu – in the synthesis of the two series
of compounds described in the begin of this report – is any-
way disturbed by using appropriated reagents, the final
products can be essentially different, structurally as well
as chemically. We report now on the effects of these con-
trolled ‘‘disturbances’’ on the intermediary mesTeI and
the structural characterization of the new organotellurium
iodides [mesTeI(l-I)2(TeImes)2]n (mes = mesityl) (1),
(C5H6N)4[mesTeI2]2 (I3)2 (2) and {(C5H6N)3[(mesTeI3)(l-
Iꢀ)(TeI3mes)](I3)2} n (3). All the three complexes show unu-
sual compositions and configurations: 2 (TeII) and 3 (TeIV)
attain secondary, interanionic Iꢀ3 ꢁ ꢁ ꢁ I–Teꢀ bonds and N+–
Hꢁ ꢁ ꢁI–Teꢀ interactions; N+–Hꢁ ꢁ ꢁ Iꢀ3 contacts are present
only in 3. Complex 2 form single dimers, but 1 and 3
assemble onedimensional, polymeric chains. The neutral
complex [mesTeI(l-I)2(TeImes)2]n (1) represents one spe-
cific example of organochalcogen halides with the chalco-
gen atoms presenting mixed valence states – TeII and
TeIV – in the same molecule.
(C5H6N)4[mesTeI2]2(I3)2 (2): hygroscopic, rectangular
black crystals. C19H23I5N2Te (1041.49). Yield: 90.0% based
on (mesTe)2; Melting point: 152.8–154.2 ꢁC. C, H, N-anal-
ysis, Found: C, 21.54; H, 2.46; N, 2.89. Calc.: C, 21.91; H,
2.23; N, 2.69%.
IR (KBr): 3198.5, 3142.3 [m(N–H)], 3052.5 [m(C–H)ar],
2961.8 [m(C–H)me], 1626.5 [m(C@C)], 1593.6 [m(C@N)],
1522.9 [d(C–C–H)], 1475.0 [d(C–N–H)], 856.5 [dout pl. (C–
C–H)mes], 736.2, 666.6 cmꢀ1 [dout pl. (C–C–H)pyr].
{(C5H6N)3[(mesTeI3)(l-Iꢀ)(TeI3mes)](I3)2}n (3): hygro-
scopic, rectangular black crystals. C33H40I13N3Te2
(2383.58). Yield: 88.0% based on (mesTe)2; Melting point:
143.8–145.5 ꢁC. C, H, N-analysis, Found: C, 15.75; H,
1.95; N, 2.05. Calc.: C, 16.63; H, 1.69; N, 1.76%.
IR (KBr): 3215.0 [m(N–H)], 3152.4 [m(C–H)ar], 3057.2
[m(C–H)me], 1627.7 [m(C@C)], 1595.0 [m(C@N)], 1524.1
[d(C–C–H)], 1475.7 [d(C–N–H)], 837.4 [dout
(C–C–
pl.
H)mes], 726.5, 662.3 cmꢀ1 [dout pl. (C–C–H)pyr].
2. Experimental
All manipulations were conducted under argon by use
of standard Schlenk techniques. The solvents were dried
(toluene with sodium/benzophenone, CH2Cl2 with CaCl2)
and distilled before use.
2.3. Crystallography
Single crystals fixed on a glass fiber were used for the
X-ray data collection. Data were collected with a Bruker
APEX II CCD area-detector diffractometer and graphite-
monochromatized Mo Ka radiation. Computing data
reduction and absorption correction [8]. The structures of
[mesTeI(l-I)2(TeImes)2]n (1), (C5H6N)4[mesTeI2]2 (I3)2 (2)
and {(C5H6N)3[(mesTeI3)(l-Iꢀ)(TeI3mes)](I3)2}n (3) were
solved by direct methods [9] and refined on F2 with aniso-
tropic temperature parameters for all non H atoms [10]. H
atoms of the mesityl groups were positioned geometrically
2.1. [mesTeI(l-I)2(TeImes)2]n (1)
To a solution of (mesTe)2 (0.148 g, 0.3 mmol) in 5 ml of
toluene, 0.077 g (0.3 mmol) of resublimated iodine were
added. The color of the solution turned blue (formation
of the intermediary mesTeI). To this mixture KI (0.050 g,
0.3 mmol) was added as seed crystal (the alternative addi-
tion of 0.3 mmol of CsI or CsCl do not change the end
results). After 5 h stirring the solution was concentrated
and allowed to recrystallize at ꢀ18 ꢁC.
2
˚
(C–H = 0.93 A for Csp atoms) and treated as riding on
their respective C atoms, with Uiso(H) values set at
1.2UeqCsp2. The hydrogen atom (N–H) of the pyridonium
ion was located in a difference-Fourier map and refined iso-
tropically. The crystallographic parameters and details of
data collection and refinement are given in Table 1.
Properties: air stable, cubic blue crystals. C27H33I5Te3
(1374.83). Yield: 90.0% based on (mesTe)2; Melting point:
159.9–161.2 ꢁC. C, H, N-analysis, Found: C, 23.49; H,
2.55; N, 0.00. Calc.: C, 23.59; H, 2.42; N, 0.00%.
IR (KBr): 2961.8 [m(C–H)ar], 2908.8 [m(C–H)me], 1588.2
[m(C@C)], 1436.1 [d(C–C–H)], 848.6 cmꢀ1 [dout pl. (C–C–
H)mes.].
3. Results and discussion
Crystal data and experimental conditions are given in
Table 1. Selected bond distances and angles of [mesTeI(l-
I)2(TeImes)2]n (1), (C5H6N)4[mesTeI2]2 (I3)2 (2) and
{(C5H6N)3[(mesTeI3)(l-Iꢀ)(TeI3mes)] (I3)2}n (3) are listed
in Tables 2–4, with dashed lines representing the secondary
bonds. Fig. 1 represents the unidimensional assembling of
complex 1 in the ab plane; Fig. 2 shows the dimeric associ-
ation of 2. Fig. 3 displays the asymmetric unit of 3, with the
secondary interactions and charge delocalization in dashed
2.2. (C5H6N)4[mes TeI2]2(I3)2 (2),
{(C5H6N)3[(mesTeI3)(l-Iꢀ)(TeI3mes)](I3)2}n(3)
To a solution of (mesTe)2 (0.148 g, 0.3 mmol) in 5 ml of
toluene, 0.077 g (0.3 mmol) of resublimated iodine were
added. The color of the solution turned immediately blue.
After addition of pyridinium iodide (0.096 g, 0.6 mmol) the