Synthesis and properties of the ditelluroethers m- and p-C6 H4(CH2TeMe)2

Article abstract of DOI:10.1016/j.jorganchem.2003.12.033

The new ditelluroethers m-C₆H₄(CH₂TeMe) ₂ and p-C₆H₄(CH₂TeMe) ₂ have been prepared in good yield from nucleophilic reaction of m- or p-C₆H₄(CH

Full text of DOI:10.1016/j.jorganchem.2003.12.033

Journal of Organometallic Chemistry 689 (2004) 1006–1013
www.elsevier.com/locate/jorganchem
Synthesis and properties of the ditelluroethers
m- and p-C6H4(CH2TeMe)2 and their Te(IV) derivatives: crystal
structures of PhTeI2(CH2)3TeI2Ph, m-C6H4(CH2TeI2Me)2 and
p-C6H4(CH2TeI2Me)2
*
Matthew J. Hesford, Nicholas J. Hill, William Levason, Gillian Reid
Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK
Received 20 October 2003; accepted 8 December 2003
Abstract
The new ditelluroethers m-C6H4(CH2TeMe)2 and p-C6H4(CH2TeMe)2 have been prepared in good yield from nucleophilic re-
action of m- or p-C6H4(CH2Br)2 and LiTeMe in THF solution. Reaction of the new ditelluroethers with MeI or I2 affords the light
yellow m- or p-C6H4(CH2TeMe2I)2 or the red/orange m- or p-C6H4(CH2TeI2Me)2, respectively in high yield. These compounds have
1
been characterised by IR, H, 13C{1H} and 125Te{1H} NMR spectroscopy and EI mass spectrometry as appropriate. The crystal
structures of the di-iodo derivatives m-C6H4(CH2TeI2Me)2, p-C6H4(CH2TeI2Me)2 and the related PhI2Te(CH2)3TeI2Ph (prepared
from PhTe(CH2)3TePh and diiodine in THF solution) are described. In each compound the TeI2 units are axial and significant
ꢀ
intermolecular Teꢀ ꢀ ꢀI secondary contacts (ꢁ3.6–4.1 A) are evident, which link these covalent compounds into extended networks
with each Te atom in a distorted 6-coordinate environment.
Ó 2004 Elsevier B.V. All rights reserved.
Keywords: Tellurium; X-ray structures; Secondary interactions
1. Introduction
characterisation of new telluroethers we often prepare
methiodide or diiodide Te(IV) derivatives, since these
are air-stable and therefore more easily handled, e.g. the
macrocyclic Te(IV) di-iodides [11]aneS2TeI2 (1,4-dithia-
8,8-diiodo-8-telluracycloundecane) and [12]aneS2TeI2
(1,5-dithia-9,9-diiodo-9-telluracyclododecane) and the
telluronium species [9]aneS2TeMeI (1,4-dithia-7-methyl-
7-iodo-7-telluracyclononane), [11]aneS2TeMeI (1,4-di-
thia-8-methyl-8-iodo-8-telluracycloundecane) and [12]
aneS2TeMeI (1,5-dithia-9-methyl-9-iodo-9-telluracyclod-
odecane) [7] and IMeRTe(CH2)3}2TeMeI (R ¼ Me or
Ph) [6].
Several classes of organotelluronium halide com-
pounds are known, including species of general formula
RTeX3, R2TeX2 and R3TeX and these have been
reviewed [9]. In addition to their value in providing
supporting spectroscopic characterisation for the tellu-
roethers, these Te(IV) compounds are themselves often
structurally very interesting, owing to the occurrence of
secondary Teꢀ ꢀ ꢀX bonding interactions which can result
We have been interested for some time in the syn-
thesis and coordination chemistry of polydentate and
macrocyclic telluroether ligands with transition metal
and p-block ions [1–8]. Unlike thioether chemistry,
where the ligand synthesis is not affected significantly by
the inter-donor linkage, in telluroethers the choice of
inter-donor linkage can play an important role in de-
termining the course of the organotellurium reaction
chemistry and thus, only a restricted range of linking
units have been incorporated to-date [1]. However, the
inter-donor unit can also influence considerably the
metal binding properties of the ligands, hence we wish to
extend the range of di- and poly-tellurother compounds
to investigate these factors further. In the course of our
* Corresponding author. Tel.: +44-238-059-3609; fax: +44-238-059-
3781.
E-mail address: gr@soton.ac.uk (G. Reid).
0022-328X/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2003.12.033

M.J. Hesford et al. / Journal of Organometallic Chemistry 689 (2004) 1006–1013
1007
in dimeric or higher oligomeric assemblies [9,10].
We have previously examined the structure adopted by
the telluronium derivative of the xylyl-linked o-C6H4
(CH2TeMe)2 [11]. The crystal structure of o-C6H4
(CH2TeMe2I) shows a weakly associated dimer, assem-
bled through a series of secondary Teꢀ ꢀ ꢀI interactions to
give a pseudo-cubane Te4I4 core, involving 3-coordinate
(pyramidal) iodine and 6-coordinate (distorted octahe-
dral) tellurium. The o-xylyl backbone units are oriented
across the diagonal of two opposite faces of the cubane.
The unusual motif in this species prompted us to probe
the occurrence of secondary bonding interactions in
other Te(IV) iodide compounds derived from related
xylyl-based ditelluroethers.
poorly soluble in chlorocarbon solvents, hence NMR
measurements were made using solutions in d6-dmso.
The H NMR spectra show resonances consistent with
conversion of Te(II) to Te(IV). The 13C{1H} NMR
spectra show significant high frequency shifts in d(Me)
[7.1 ppm and 6.9 ppm, respectively], and a high fre-
quency shift in the 125Te{1H} NMR resonance to 531
and 537 ppm for the m- and p-derivatives, respectively
(compare 526 for o-C6H4(CH2TeMe2I)2) [11].
1
The o-, m- and p-C6H4(CH2TeMe)2 also react with
di-iodine in THF solution to give the Te(IV) halide
compounds o-, m- or p-C6H4(CH2TeI2Me)2 as red/or-
ange solids in good yield. These assignments follow from
1
microanalytical, IR and H NMR spectroscopic data.
In this paper we describe preparations for the new
ditelluroethers m- and p-C6H4(CH2TeMe)2 which in-
corporate linkages likely to lead to extended networks
upon coordination to metal ions. The preparation and
spectroscopic characterisation of the tellurium(IV) de-
rivatives m- and p-C6H4(CH2TeMe2I)2 and m- and
p-C6H4(CH2TeI2Me)2 are also described. Crystal struc-
tures of the di-iodo Te(IV) species, m- and p-C6H4
(CH2TeI2Me)2 and the related PhTeI2(CH2)3TeI2Ph,
are presented and the structures compared with relevant
literature examples.
The o-C6H4(CH2TeI2Me)2 decomposes appreciably
over an hour or so in solution, hence 13C{1H} and
125Te{1H} NMR data were not obtained for this species.
However, 13C{1H} NMR data for m- and p-C6H4
(CH2TeI2Me)2 are in accord with expectations. Most
notable is the high frequency shift in d(Me) and d(CH2)
which accompanies the conversion from Te(II) to
Te(IV). Also, d(125Te{1H}) for the m- and p-C6H4
(CH2TeI2Me)2 (738 ad 739 ppm) lie to higher frequency
than for the Te(IV) methiodide derivatives above, con-
sistent with other diorgano-Te(IV)-diiodide compounds,
cf. PhMeTeI2 698 ppm [12].
In order to examine the occurrence and extent of
Teꢀ ꢀ ꢀI secondary interactions, and the effect of these on
the environment at tellurium, crystallographic analy-
ses of certain of the Te(IV) derivatives were sought.
Single crystals of m-C6H4(CH2TeI2Me)2, p-C6H4
(CH2TeI2Me)2 and the related PhI2Te(CH2)3TeI2Ph
were obtained as described in Section 3. The crystal
structure of m-C6H4(CH2TeI2Me)2 (Fig. 1, Table 1)
confirms that this is an essentially covalent compound
with two iodines coordinated to each Te atom in an
axial arrangement (hence Te(IV) formally), with the
–CH2TeI2Me units lying directed on opposite sides of the
arene unit. The geometry at each Te is pseudo-trigonal
bipyramidal, with the Te-based lone pair assumed to
occupy the vacant equatorial vertex. The primary Te–I
2. Results and discussion
The new xylyl-based ditelluroether compounds m-
and p-C6H4(CH2TeMe)2 were obtained in good yield by
reaction of freshly ground elemental tellurium with
MeLi at 77 K in THF, which upon warming to room
temperature produces MeTeLi. Addition of 0.5 mol.
equivs. of m-C6H4(CH2Br)2 or p-C6H4(CH2Br)2 to this
at 77 K and warming to RT affords the two new tellu-
roethers m-C6H4(CH2TeMe)2 or p-C6H4(CH2TeMe)2
respectively as air-sensitive, yellow solids in good yield.
These formulations follow from their H and 13C{1H}
1
NMR spectra, with the latter showing the diagnostic
d(TeMe) at ca. )20 ppm. These compounds also show a
single 125Te{1H} resonance, coincidentally both occur at
311 ppm. These compare with d 264 in the related o-
C6H4(CH2TeMe)2 [3]. The substitution patterns in the
xylyl linkages of these compounds would suggest that
they are less likely to chelate to metal ions than the
o-C6H4(CH2TeMe)2.
Reaction of these compounds with excess MeI in
CH2Cl2 solution affords the telluronium salts m- or p-
C6H4(CH2TeMe2I)2 (from microanalytical data) as light
yellow powdered solids in good yield. Electrospray mass
spectrometry (MeCN) shows the dicationic [m-/p-C6H4
(CH2TeMe2)2]2þ as the major species, with minor frag-
ments involving loss of Me units also evident. Unlike the
corresponding o-C6H4(CH2TeMe2I)2 which shows rea-
sonable solubility in CHCl3, the m- and p-analogues are
ꢀ
bonds lie in the range ¼ 2.870(2)–2.997(2) A, in accord
with d(Te–I) in other Te(IV) iodide compounds such as
ꢀ
[12]aneS2TeI2 (2.8990(9), 2.9179(9) A) [7] and 1,1-dii-
ꢀ
odo-3,4-benzo-1-telluracyclopentane (2.928, 2.900 A)
[13]. Examination of the crystal packing in m-C6H4
(CH2TeI2Me)2 also shows significant longer range
(secondary) Teꢀ ꢀ ꢀI interactions (Te1ꢀ ꢀ ꢀI40 ¼ 3.760(2),
00
ꢀ
Te2ꢀ ꢀ ꢀI2 ¼ 3.686 A) between adjacent molecules which
link them into an infinite array. There is a further long
intermolecular Teꢀ ꢀ ꢀI contact to each Te atom (Te1–
I2000 ¼ 4.110(2), Te2–I30000 ¼ 4.059(2) A). The van der
ꢀ
ꢀ
Waals radii for Te and I are 2.20 and 2.15 A, respec-
tively [14], hence these too may be considered as weak
contacts. In addition to the four primary bonds at each
Te centre (2C and 2I) there are therefore two secondary

1008
M.J. Hesford et al. / Journal of Organometallic Chemistry 689 (2004) 1006–1013
Fig. 1. View of the structure of m-C6H4(CH2TeI2Me)2 with numbering scheme ad0opted showing the coordi0n0 ation environment at each Te, including
1
2
1
2
000
the secondary (intermolecular) Teꢀ ꢀ ꢀI contacts (symmetry operations: ¼ 1 ꢂ x; y ꢂ 12 ; ꢂz þ ;
¼ x; 1 12 ꢂ y; z þ ;
¼ 1 ꢂ x; 1 ꢂ y; ꢂz;
0000
¼ ꢂx; 1 ꢂ y; 1 ꢂ z). Ellipsoids are drawn at 40% probability and H atoms are omitted for clarity.
Table 1
pattern has on the gross structure. The structure of this
compound is centrosymmetric, with an inversion centre
at the mid-point of the arene ring (Fig. 2, Table 2), with
trans, axial iodines bound to each Te centre. A conse-
quence of the centre of symmetry is that the
–CH2TeI2Me units lie on opposite sides of the aromatic
unit. The primary Te–I bond distances of 2.8967(8)
ꢀ
Selected bond lengths (A) and angles (°) for m-C6H4(CH2TeI2Me)2
ꢀ
Bond lengths (A)
Te1–C8 ¼ 2.12(2)
Te1–I1 ¼ 2.892(2)
Te1–C1 ¼ 3.10(2)
Te2–C10 ¼ 2.08(2)
Te2–I3 ¼ 2.870(2)
Te2–C5 ¼ 3.11(2)
Te1–I2000 ¼ 4.110(2)
Te1–C7 ¼ 2.20(2)
Te1–I2 ¼ 2.938(2)
Te1–I40 ¼ 3.760(2)
Te2–C9 ¼ 2.18(3)
Te2–I4 ¼ 2.997(2)
Te2–I200 ¼ 3.686(2)
Te2–I30000 ¼ 4.059(2)
ꢀ
and 2.9309(7) A are similar to those in m-C6H4
(CH2TeI2Me)2 above. In this species there are two sig-
nificant intermolecular secondary bonding interactions
to each Te, Te1ꢀ ꢀ ꢀI2000 ¼ 3.6519(8), Te1ꢀ ꢀ ꢀI100 ¼ 3.7979(7)
Bond angles (°)
C8–Te1–C7 ¼ 99.0(9)
C7–Te1–I1 ¼ 87.3(6)
C7–Te1–I2 ¼ 87.1(6)
C8–Te1–I40 ¼ 166.0(7)
I1–Te1–I40 ¼ 101.24(6)
C10–Te2–C9 ¼ 102.0(9)
C9–Te2–I3 ¼ 89.4(7)
C9–Te2–I4 ¼ 84.2(7)
C10–Te2–I200 ¼ 170.0(7)
I3–Te2–I200 ¼ 99.15(6)
C8–Te1–I1 ¼ 89.4(7)
C8–Te1–I2 ¼ 90.1(7)
I1–Te1–I2 ¼ 174.20(7)
C7–Te1–I40 ¼ 72.8(6)
I2–Te1–I40 ¼ 78.41(5)
C10–Te2–I3 ¼ 90.1(7)
C10–Te2–I4 ¼ 89.7(7)
I3–Te2–I4 ¼ 173.41(8)
C9–Te2–I200 ¼ 74.6(6)
I4–Te2–I200 ¼ 80.62(5)
ꢀ
A, which result in a complicated infinite array. Overall
each Te1 atom is again in a very distorted octahedral
environment comprising two Te–C bonds, two primary
Te–I bonds and two secondary Teꢀ ꢀ ꢀI bonds.
Although the secondary Teꢀ ꢀ ꢀI contacts are at similar
distances, the extended structures identified in these m-
and p-xylyl species are quite different from the weakly
associated dimer observed in o-C6H4(CH2TeMe2I). This
is almost certainly in part due to the different architec-
tures of the units linking the Te atoms, which prevent
simple dimer formation.
Symmetry operations: ¼ 1 ꢂ x; y ꢂ 12 ; ꢂz þ ; ¼ x; 1 21 ꢂ y; z þ ;
0
1
2
00
1
2
000
0000
¼ 1 ꢂ x; 1 ꢂ y; ꢂz; ¼ ꢂx; 1 ꢂ y; 1 ꢂ z).
interactions, giving a distorted octahedral environment
at Te.
The crystal structure of the para-substituted ana-
logue, p-C6H4(CH2TeI2Me)2, was also determined to
allow us to probe the influence that the substitution
The related ditelluroether PhTe(CH2)3TePh reacts
similarly with excess I2 in THF solution to give
PhTeI2(CH2)3TeI2Ph as a red-black powder in moderate
yield. The 125Te{1H} NMR spectrum of this product

M.J. Hesford et al. / Journal of Organometallic Chemistry 689 (2004) 1006–1013
1009
Fig. 2. (a) View of the centrosymmetric structure of p-C6H4(CH2TeI2Me)2 with numbering scheme adopted. Ellipsoids are drawn at 40% probability
0
(symmetry operation: ¼ 1 ꢂ x; ꢂy; 1 ꢂ z); (b) diagram showing the coordination environment at Te1, including the secondary (intermolecular)
00
000
1
2
Teꢀ ꢀ ꢀI contacts (symmetry operations: ¼ 2 ꢂ x; ꢂy; 2 ꢂ z; ¼ x; 12 ꢂ y; z þ ).
ꢀ
shows a singlet at 651 ppm, once again significantly to
high frequency of the parent telluroether (466 ppm).
The crystal structure of PhTeI2(CH2)3TeI2Ph (Fig. 3,
Table 3) adopts crystallographic 2-fold symmetry, with
C1, the central carbon in the trimethylene linkage, oc-
cupying a 2-fold symmetry site (0, y, 3/4). A similar saw-
horse geometry is observed at tellurium, like in the
structures above, with the iodines axial and the Te-
bonded C atoms equatorial. The primary Te–I bonds lie
in the range 2.883(4)–2.938(3) A, in accord with both m-
and p-C6H4(CH2TeI2Me)2 above. Closer inspection of
the packing of the PhTeI2(CH2)3TeI2Ph units again re-
veals an extended network formed through secondary
Te1ꢀ ꢀ ꢀI100 interactions of 3.702(4) A, giving weakly
ꢀ
bound chains with the linear I–Te–I units in adjacent
molecules aligned parallel and Te2I2 rhomboid units.
Further, weaker Te1ꢀ ꢀ ꢀI000 contacts (4.0712(6) A) be-
ꢀ
tween a Te atom within each Te2I2 rhomboid and an I

1010
M.J. Hesford et al. / Journal of Organometallic Chemistry 689 (2004) 1006–1013
Table 2
atom diagonally opposite give rise to a Ôcradle-likeÕ motif
comprised of three Te2I2 units. One face of the cradle is
shared between two units, giving an alternating Ôup-
downÕ chain arrangement, with the trimethylene linkage
between the Te atoms straddling diagonally across the
top of each cradle. Overall, the environment at each Te
centre is pseudo-six coordinate, although the bond
angles are severely distorted from regular octahedral.
A number of Te(IV) di-iodide compounds derived
from monotelluroethers have been examined crystallo-
graphically, e.g. Me2TeI2. The environment at Te in the
a-form is similar to the compounds described in this
work, and involves two axial iodines (2.885(3) and
ꢀ
Selected bond lengths (A) and angles (°) for p-C6H4(CH2TeI2Me)2
ꢀ
Bond lengths (A)
C1–Te1 ¼ 2.241(10)
C5–Te1 ¼ 2.137(8)
Te1–I1 ¼ 2.8967(8)
Te1–I2 ¼ 2.9309(7)
Te1–I2000 ¼ 3.6519(8)
Te1–I100 ¼ 3.7979(7)
Bond angles (°)
C5–Te1–C1 ¼ 100.7(3)
C5–Te1–I1 ¼ 87.8(3)
C1–Te1–I1 ¼ 89.0(2)
C5–Te1–I2 ¼ 88.1(3)
C1–Te1–I2 ¼ 88.1(2)
I1–Te1–I2 ¼ 174.48(2)
C5–Te1–I2000 ¼ 85.3(3)
C1–Te1–I2000 ¼ 173.6(2)
I1–Te1–I2000 ¼ 93.38(2)
I2–Te1–I2000 ¼ 89.914(19)
C5–Te1–I100 ¼ 162.7(3)
C1–Te1–I100 ¼ 84.0(2)
I1–Te1–I100 ¼ 109.138(18)
I2–Te1–I100 ¼ 75.272(18)
ꢀ
2.965(3) A), two cis Me groups and two weak, inter-
ꢀ
molecular Teꢀ ꢀ ꢀI contacts (3.659(3), 3.919(3) A), giving
an extended array [15]. These distances compare well
with those reported here. The b-form subsequently
turned out to be the ionic species [TeMe3][TeMeI4]
[16]. The structure of (CH2{p-(OMe)-C6H4TeI2}2)
has been described by Singh and co-workers and in-
volves long intermolecular Teꢀ ꢀ ꢀI contacts of 3.735(1)–
Symmetry operations: ¼ 2 ꢂ x; ꢂy; 2 ꢂ z; ¼ x; 12 ꢂ y; z þ .
3.879(1) A [17].
00
000
1
2
ꢀ
Fig. 3. View of the structure of PhTeI2(CH2)3TeI2Ph, with numbering scheme adopted, showing the environment at the Te centres and including
intermolecular secondary interactions. Ellipsoids are drawn at 40% probability and H atoms are omitted for clarity (symmetry operations:
0
00
000
¼ ꢂx; y; 1 12 ꢂ z; ¼ ꢂx; 2 ꢂ y; 1 ꢂ z; ¼ x; 2 ꢂ y; 12 þ z).

M.J. Hesford et al. / Journal of Organometallic Chemistry 689 (2004) 1006–1013
1011
Table 3
and PhTe(CH2)3TePh were prepared as described
previously [3,5].
ꢀ
Selected bond lengths (A) and angles (°) for PhTeI2(CH2)3TeI2Ph
ꢀ
Bond lengths (A)
I1–Te1 ¼ 2.9377(6)
I100–Te1 ¼ 3.7020(6)
I2–Te1 ¼ 2.8835(6)
I1000–Te1 ¼ 4.0712(6)
Te1–C3 ¼ 2.082(14)
Te1–C2 ¼ 2.155(6)
Te1–C3B ¼ 2.187(17)
3.1. Preparations
m-C6H4(CH2TeMe)2: Freshly ground tellurium
powder (1.59 g, 12.5 mmol) was frozen (77 K) in THF
(70 cm3) and MeLi (12.5 mmol) added. The mixture was
allowed to warm to room temperature and stirred for 30
min to form a clear yellow solution of MeTeLi. The
mixture was then refrozen (77 K) and a solution of m-
C6H4(CH2Br)2 (1.65 g, 6.25 mmol) in dry THF (30 cm3)
added. The mixture was then allowed to warm to room
temperature and stirred for 20 h, before hydrolysing (ca.
50 cm3 with degassed water) and extracting with CH2Cl2
(2 ꢃ 50 cm3). The combined organic extracts were dried
(MgSO4), filtered and the solvent removed to give a light
yellow solid. Yield 1.69 g, 69%. Melting point 64 °C.
EIMS: found 390 (m-C6H4(CH2TeMe)2). 1H NMR
(CDCl3): d 7.0–7.2 (m, 4H, m-C6H4), 4.0 (s, 4H, CH2),
1.95 (s, 6H, Me) ppm. 13C{1H} NMR (CDCl3): d 141.4
(ipso-C, m-C6H4), 128.8 (1C, m-C6H4), 128.6 (1C,
m-C6H4), 126.4 (2C, m-C6H4), 5.7 (CH2Te), )20.1
(TeMe) ppm. 125Te{1H} NMR (CDCl3): d 311 ppm. IR
(CsI disk): 3060w, 2920w, 1592w, 1584w, 1481m,
1435m, 1414m, 1263w, 1260m, 1246w, 1214m, 1150m,
1142m, 1116m, 1068m, 927w, 900w, 847m, 830m, 797m,
699m, 536m, 525w, 427w, 392w, 383w, 275w, 246w,
Bond angles (°)
C3–Te1–C2 ¼ 105.7(5)
C2–Te1–C3B ¼ 94.5(5)
C3–Te1–I2 ¼ 91.5(4)
C2–Te1–I2 ¼ 84.79(17)
C3B–Te1–I2 ¼ 88.7(4)
C3–Te1–I1 ¼ 86.5(4)
C2–Te1–I1 ¼ 95.23(17)
C3B–Te1–I1 ¼ 89.2(4)
I2–Te1–I1 ¼ 177.93(2)
C3–Te1–I100 ¼ 175.9(4)
C2–Te1–I100 ¼ 75.04(17)
C3B–Te1–I100 ¼ 169.2(5)
I2–Te1–I100 ¼ 92.576(16)
I1–Te1–I100 ¼ 89.426(15)
Symmetry operations: ¼ ꢂx; 2 ꢂ y; 1 ꢂ z; ¼ x; 2 ꢂ y; 12 þ z.
00
000
These results show that xylyl units involving different
substitution patterns can be introduced readily as link-
ing units in ditelluroethers. The crystallographic studies
reveal interesting extended structures for the di-iodo
Te(IV) complexes with significant secondary Teꢀ ꢀ ꢀI
bonding interactions linking the monomer units and
demonstrate that the xylyl substitution pattern, and
more generally the nature of the inter-donor linking unit
in these compounds also plays a significant role in de-
termining the nature of these secondary interactions and
hence the extended structures adopted.
221w cmꢂ1
.
p-C6H4(CH2TeMe)2: Method and work-up as
above, using freshly ground tellurium powder (1.59 g,
12.5 mmol), MeLi (12.5 mmol) and p-C6H4(CH2Br)2
(1.65 g, 6.25 mmol) to give a yellow solid. Yield 1.98 g,
82%. Melting point 85 °C. EIMS: found 390 (p-
C6H4(CH2TeMe)2). 1H NMR (CDCl3): d 7.05 (s, 4H, p-
C6H4), 3.9 (s, 4H, CH2), 1.75 (s, 6H, Me) ppm. 13C{1H}
NMR (CDCl3): d 138.8 (ipso-C, p-C6H4), 129.0 (p-
C6H4), 5.3 (CH2Te), )20.1 (TeMe) ppm. 125Te{1H}
NMR (CDCl3): d 311 ppm. IR (CsI disk): 3050w,
2925w, 2853w, 1600w, 1502m, 1457w, 1419m, 1364m,
1261m, 1214m, 1104m, 1018m, 861w, 830m, 614w,
3. Experimental
Infrared spectra were recorded as CsI discs using a
Perkin–Elmer 983G spectrometer over the range 4000–
200 cmꢂ1. Mass spectra were run by electron impact on
a VG-70-SE Normal geometry double focusing spec-
trometer or by positive ion electrospray (MeCN solu-
586m, 523w, 462w, 315w, 246w, 222w cmꢂ1
.
m-C6H4(CH2TeMe2I)2: MeI (ca. 1 cm3, excess) was
added to a solution of m-C6H4(CH2TeMe)2 (0.12 g, 0.31
mmol) in CH2Cl2 (50 cm3) and the mixture stirred at
room temperature for 2 h. The resulting cloudy yellow
solution was concentrated (ca. 25 cm3) and Et2O (ca. 20
cm3) added. The resultant precipitate was filtered off and
washed with Et2O to give a pale yellow powdered solid.
Yield 0.150 g, 72%. Required for C12H20I2Te2 ꢀ 1/2Et2O:
C, 23.7; H, 3.5%. Found: C, 24.5; H, 3.5%. Electrospray
MS (MeCN): found 547 ([m-C6H4(CH2TeMe2)2I]þ), 210
1
tion) using a VG Biotech platform. H NMR spectra
were recorded using a Bruker AM300 spectrometer.
13C{1H} and 125Te{1H} NMR spectra were recorded
using a Bruker DPX400 spectrometer operating at 100.6
or 126.3 MHz, respectively and are referenced to TMS
and external neat Me2Te, respectively. Microanalyses
were undertaken by the University of Strathclyde mi-
croanalytical service.
([m-C6H4(CH2TeMe2)2]2þ). H NMR (d6-dmso): d 7.0–
1
Solvents were dried prior to use and all preparations
were undertaken using standard Schlenk techniques un-
der a N2 atmosphere. The ligands o-C6H4(CH2TeMe)2
7.5 (m, 4H, m-C6H4), 4.1 (s, 4H, CH2), 1.9 (s, 12H, Me)
ppm. 13C{1H} NMR (d6-dmso): d 134.7 (ipso-C, m-
C6H4), 131.8 (1C, m-C6H4), 131.6 (1C, m-C6H4), 129.7

1012
M.J. Hesford et al. / Journal of Organometallic Chemistry 689 (2004) 1006–1013
(2C, m-C6H4), 29.1 (CH2Te), 7.1 (TeMe) ppm.
125Te{1H} NMR (d6-dmso): d 531 ppm. IR (CsI disk):
3014w, 2977w, 2922w, 2861w, 1600w, 1584w, 1483m,
1441m, 1414m, 1360m, 1227m, 1155m, 1119m, 1075w,
934w, 893w, 856m, 803m, 741w, 708m, 617w, 541m,
797w, 761m, 615w, 555m, 523w, 325w, 300w, 247w,
223w cmꢂ1
.
m-C6H4(CH2TeI2Me)2: Method as above using m-
C6H4(CH2TeMe)2 (0.10 g, 0.26 mmol) and I2 (0.13 g,
0.51 mmol). Red/orange solid. Yield 0.109 g, 47%. Re-
quired for C10H14I4Te2 ꢀ 1/2Et2O: C, 15.4; H, 2.0%.
431w, 340w, 244w, 222w cmꢂ1
.
p-C6H4(CH2TeMe2I)2: MeI (ca. 1 cm3, excess) was
added to a solution of p-C6H4(CH2TeMe)2 (0.12 g, 0.31
mmol) in CH2Cl2 (50 cm3) and the mixture stirred at room
temperature for 2 h. The resultant precipitate was filtered
off and washed with Et2O to give a pale yellow powdered
solid. Yield 0.150 g, 72%. Required for C12H20I2Te2:
C, 21.4; H, 3.0%. Found: C, 22.0; H, 3.2%. Electro-
spray MS (MeCN): found 405 ([p-C6H4(CH2TeMe)
(CH2TeMe2)]þ), 210 ([p-C6H4(CH2TeMe2)2]2þ). 1H
NMR (d6-dmso): d 7.3 (s, 4H, p-C6H4), 4.05 (s, 4H, CH2),
1.8 (s, 12H, Me) ppm. 13C{1H} NMR (d6-dmso): d 133.4
(ipso-C, p-C6H4), 130.9 (p-C6H4), 28.2 (CH2Te), 6.9
(TeMe) ppm. 125Te{1H} NMR (d6-dmso): d 537 ppm. IR
(CsI disk): 3017w, 2923w, 2858w, 1600w, 1506w, 1418m,
1358m, 1263w, 1227m, 1203w, 1128m, 1101m, 1018sh,
994m, 890w, 835m, 732w, 614w, 586m, 533w, 417w, 312w,
Found: C, 15.6; H, 1.4%. H NMR (d6-dmso): d 7.15–
1
7.65 (m, 4H, m-C6H4), 4.6 (s, 4H, CH2), 2.4 (s, 6H, Me)
ppm. 13C{1H} NMR (CDCl3): d 133.2, 130.5, 130.3
(2C), 128.1 (m-C6H4), 41.3 (CH2Te), 10.8 (TeMe) ppm.
125Te{1H} NMR (CDCl3): d 738 ppm. IR (CsI disk):
3017w, 2943w, 2858w, 1582w, 1482m, 1436w, 1406m,
1253w, 1213w, 1161m, 1150m, 1117w, 1100w, 1073m,
997w, 940w, 849m, 819w, 805m, 794m, 703m, 558w,
538sh, 531m, 394w, 348w, 324w, 300w, 224w cmꢂ1
.
p-C6H4(CH2TeI2Me)2: Method as above using p-
C6H4(CH2TeMe)2 (0.10 g, 0.26 mmol) and I2 (0.13 g,
0.51 mmol). Red/orange solid. Yield 0.092 g, 40%. Re-
quired for C10H14I4Te2: C, 13.4; H, 1.6%. Found: C,
13.9; H, 1.8%. 1H NMR (d6-dmso): d 7.5 (s, 4H, p-
C6H4), 4.65 (s, 4H, CH2), 2.35 (s, 6H, Me) ppm.
13C{1H} NMR (CDCl3): d 133.6 (ipso-C, p-C6H4), 129.4
(p-C6H4), 41.4 (CH2Te), 20.9 (TeMe) ppm. 125Te{1H}
NMR (CDCl3): d 739 ppm. IR (CsI disk): 3020w,
2940w, 2863w, 1540w, 1501w, 1420m, 1396sh, 1358m,
1262w, 1216w, 1138m, 1107m, 1081m, 1020w, 995m,
829m, 792w, 759w, 626w, 573m, 434w, 415w, 312w,
224w cmꢂ1
.
o-C6H4(CH2TeI2Me)2: To a solution of o-C6H4
(CH2TeMe)2 (0.10 g, 0.26 mmol) in dry THF (30 cm3)
was added a solution of I2 (0.13 g, 0.51 mmol) in dry
THF (10 cm3) and the solution stirred in a foil-wrapped
vessel at room temperature for 2 h. The solution volume
was reduced (ca. 5 cm3) and Et2O (ca. 10 cm3) added to
form a precipitate that was filtered off, washed with
Et2O and dried in vacuo to give a red/orange solid. Yield
0.067 g, 30%. Required for C10H14I4Te2: C, 13.4; H,
247w, 222w cmꢂ1
.
PhTeI2(CH2)3TeI2Ph: To an anhydrous THF solu-
tion (10 cm3) of PhTe(CH2)3TeMe (0.11 g, 0.12 mmol)
was added a THF solution (5 cm3) of I2 (0.2 g). The red-
black solution was stirred at room temperature for 2 h
and the solvent was removed in vacuum to leave a dark
red/orange powder, which was washed with hexane and
dried in vacuo. Yield 46%. Required for C15H16 I4Te2:
C, 18.8; H, 1.7%. Found: C, 18.5; H, 1.5%. 125Te{1H}
NMR (CDCl3): d 651.
1
1.6%. Found: C, 13.8; H, 1.5%. H NMR (d6-dmso): d
7.2–7.4 (m, 4H, o-C6H4), 4.30 (s, 4H, CH2), 2.95 (s, 6H,
Me) ppm. IR (CsI disk): 3020w, 2959w, 2925w, 2857w,
1595w, 1484m, 1446m, 1396w, 1359m, 1261w, 1220m,
1197w, 1128m, 1101sh, 1054m, 952w, 860w, 834sh,
Table 4
Crystallographic parameters
Complex
Formula
M
m-C6H4(CH2TeI2Me)2
10H14I4Te2
897.01
p-C6H4(CH2TeI2Me)2
C10H14I4Te2
897.01
PhTeI2(CH2)3TeI2Me
C15H16I4Te2
959.11
C
Crystal system
Space group
Monoclinic
P21=c (#14)
10.018(2)
9.2154(18)
20.264(4)
98.30(3)
1851.2(6)
4
Monoclinic
P21=c (#14)
10.8286(7)
9.2821(3)
9.4672(6)
104.816(2)
919.93(9)
2
Orthorhombic
Pbcn (#60)
23.6450(2)
9.0897(2)
10.1816(3)
90
ꢀ
a (A)
ꢀ
b (A)
ꢀ
c (A)
b (°)
U (A )
3
ꢀ
2188.29(5)
4
83.03
Z
l (Mo Ka)/cmꢂ1
Unique reflections
No. of parameters
R1½I0 > 2rðI0Þꢄ
wR2½I0 > 2rðI0Þꢄ
98.02
4146
98.62
2089
2496
90
145
0.0786
0.1857
74
0.0521
0.1283
0.0390
0.0978
h
i
1=2
P
P
P
P
2
R1 ¼ jjFoj ꢂ jFcjji= jFoj, wR2 ¼
wðFo2 ꢂ Fc2Þ = wFo4i
.

M.J. Hesford et al. / Journal of Organometallic Chemistry 689 (2004) 1006–1013
1013
3.2. X-ray crystallography
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Details of the crystallographic data collection and re-
finement parameters are given in Table 4. Orange plate
crystals of m-C6H4(CH2TeI2Me)2, p-6H4(CH2TeI2Me)2
and PhTeI2(CH2)3TeI2Ph were grown by slow evapora-
tion from a solution of the appropriate compound in
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fractometer (T ¼ 120 K) and with graphite-monochro-
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ꢀ
mated Mo Ka X-radiation (k ¼ 0:71073 A). Structure
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of the phenyl rings. This was modelled reasonably suc-
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each with 50% occupancy. Selected bond lengths and
angles are given in Tables 1–3.
[7] W. Levason, S.D. Orchard, G. Reid, Chem. Commun. (2001) 427;
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4. Supplementary material
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Crystallographic data for the structural analyses have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC nos. 221911-221913. Copies of this
information may be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge CD2
1EZ, UK (Fax: +44-1223-336033; email: deposit@ccdc.
cam.ac.uk or www:http://www.ccdc.cam.ac.uk).
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Oxford, 1998.
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[18] G.M. Sheldrick, SHELXS-97, program for crystal structure solu-
Acknowledgements
€
tion, University of Gottingen, 1997.
[19] G.M. Sheldrick, SHELXL-97, program for crystal structure
€
refinement, University of Gottingen, 1997.
We thank the EPSRC for support.