The reactivity of diorganotellurium oxides towards phenol and o-nitrophenol. Hypervalent and secondary bonding of four different product classes

Article abstract of DOI:10.1071/CH07329

The reaction of the diorganotellurium oxides R₂TeO (R ≤ Ph, p-MeOC₆H₄, p-Me₂NC₆H₄) with phenol and o-nitrophenol produces diorganotellurium hydroxy phenolates, R₂Te(OH)OPh (1, R ≤ Ph; 2, R ≤ p-MeOC₆H₄; 3, R ≤ p-Me₂NC₆H₄), diorganotellurium bis(phenolates) R₂Te(OPh)₂ (4, R ≤ Ph; 5, R ≤ p-MeOC₆H₄; 6, R ≤ p-Me₂NC₆H ₄), tetraorganoditelluroxane bis(o-nitrophenolates), (R?O)R ₂TeOTeR₂(OR?) (7, R ≤ p-MeOC₆H₄; 8, R ≤ p-Me₂NC₆H₄; R? ≤ o-NO ₂C₆H₄), and a hexaphenyltritelluroxane bis(o-nitrophenolate) (R?O)Ph₂TeOTePh₂OTePh ₂(OR?) (9, R? ≤ o-NO₂C₆H₄), respectively. The redistribution reactions of R₂Te(OPh)₂ (4, R ≤ Ph; 5, R ≤ p-MeOC₆H₄; 6, R ≤ p-Me ₂NC₆H₄) with the corresponding diorganotellurium oxides R₂TeO and diorganotellurium dichlorides R₂TeCl₂ (R ≤ Ph, p-MeOC₆H₄, p-Me₂NC₆H₄) give rise to the formation of moisture sensitive tetraorganoditelluroxane bis(phenolates) (PhO)R ₂TeOTeR₂(OPh) (10, R ≤ Ph; 11, R ≤ p-MeOC ₆H₄; 12, R ≤ p-Me₂NC₆H ₄) and diorganotellurium chloro phenolates, R₂Te(Cl)OPh (13, R ≤ Ph; 14, R ≤ p-MeOC₆H₄; 15, R ≤ p-Me ₂NC₆H₄), respectively. The reaction of the diorganotellurium oxides R₂TeO with the corresponding diorganotellurium dichlorides R₂TeCl₂ (R ≤ Ph, p-MeOC₆H₄, p-Me₂NC₆H₄) affords tetraorganoditelluroxane dichlorides ClR₂TeOTeR₂Cl (16, R ≤ Ph; 17, R ≤ p-MeOC₆H₄; 18, R ≤ p-Me₂NC₆H₄) as air-stable solid materials. The reactivity of 1?18 can be rationalized by the kinetic lability of the Te?O and Te?Cl bonds. Compounds 1?18 have been characterized by solution and solid-state ¹²⁵Te NMR spectroscopy and 2, 4, 6, 7, 9, 17, and 18 have also been analyzed by X-ray crystallography. CSIRO 2008.

Full text of DOI:10.1071/CH07329

Full Paper
CSIRO PUBLISHING
Aust. J. Chem. 2008, 61, 172–182
www.publish.csiro.au/journals/ajc
The Reactivity of Diorganotellurium Oxides Towards Phenol
and o-Nitrophenol. Hypervalent and Secondary Bonding
of Four Different Product Classes
Jens Beckmann,A,C Jens Bolsinger,A and Andrew DuthieB
AInstitut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstrasse 34/36,
14195, Berlin, Germany.
BSchool of Life and Environmental Sciences, Waurn Ponds, Vic. 3216, Australia.
CCorresponding author. Email: Beckmann@chemie.fu-berlin.de
The reaction of the diorganotellurium oxides R2TeO (R = Ph, p-MeOC6H4, p-Me2NC6H4) with phenol and o-
nitrophenol produces diorganotellurium hydroxy phenolates, R2Te(OH)OPh (1, R = Ph; 2, R = p-MeOC6H4; 3, R = p-
Me2NC6H4), diorganotellurium bis(phenolates) R2Te(OPh)2 (4, R = Ph; 5, R = p-MeOC6H4; 6, R = p-Me2NC6H4),
tetraorganoditelluroxane bis(o-nitrophenolates), (RꢀO)R2TeOTeR2(ORꢀ) (7, R = p-MeOC6H4; 8, R = p-Me2NC6H4;
Rꢀ = o-NO2C6H4), and a hexaphenyltritelluroxane bis(o-nitrophenolate) (RꢀO)Ph2TeOTePh2OTePh2(ORꢀ) (9, Rꢀ = o-
NO2C6H4), respectively. The redistribution reactions of R2Te(OPh)2 (4, R = Ph; 5, R = p-MeOC6H4; 6, R = p-
Me2NC6H4) with the corresponding diorganotellurium oxides R2TeO and diorganotellurium dichlorides R2TeCl2 (R = Ph,
p-MeOC6H4, p-Me2NC6H4) give rise to the formation of moisture sensitive tetraorganoditelluroxane bis(phenolates)
(PhO)R2TeOTeR2(OPh) (10, R = Ph; 11, R = p-MeOC6H4; 12, R = p-Me2NC6H4) and diorganotellurium chloro pheno-
lates, R2Te(Cl)OPh (13, R = Ph; 14, R = p-MeOC6H4; 15, R = p-Me2NC6H4), respectively. The reaction of the
diorganotellurium oxides R2TeO with the corresponding diorganotellurium dichlorides R2TeCl2 (R = Ph, p-MeOC6H4,
p-Me2NC6H4)affordstetraorganoditelluroxanedichloridesClR2TeOTeR2Cl(16, R = Ph;17, R = p-MeOC6H4;18, R = p-
Me2NC6H4) as air-stable solid materials. The reactivity of 1–18 can be rationalized by the kinetic lability of the Te–O
and Te–Cl bonds. Compounds 1–18 have been characterized by solution and solid-state 125Te NMR spectroscopy and 2,
4, 6, 7, 9, 17, and 18 have also been analyzed by X-ray crystallography.
Manuscript received: 16 September 2007.
Final version: 8 February 2008.
O
Introduction
Te
Although the first diorganotellurium oxides, R2TeO (R = alkyl,
aryl), were described by Lederer more than 90 years ago,[1] for a
long time little attention was directed to the structure and reactiv-
ity of this compound class, presumably because of the common
misconception that tellurium chemistry closely resembles sele-
nium chemistry. In solution, diorganotellurium oxides, such as
Ph2TeO and (p-MeOC6H4)2TeO, are only very slightly asso-
ciated and comprise mostly monomers that have polar Te=O
double bonds.[2] However, in the solid-state diorganotellurium
oxides aggregate and show surprisingly diverse structures, as
opposed to their lighter group 16 congeners. For instance,
crystalline Ph2TeO consists of two conformers with slightly
elongated Te=O double bonds, which are connected by short
secondary Te· · ·O bonds, which gives rise to asymmetric dimers
(Scheme 1).[3] The closely related (p-MeOC6H4)2TeO contains
a one-dimensional polymer with two Te–O single bonds in the
solid-state and lacks any secondary interactions (Scheme 1).[2]
Recently, we have demonstrated that diorganotellurium
oxides, such as (p-MeOC6H4)2TeO, show potential for the
preparation of binary element oxides and for applications
in the fixation of carbon dioxide.[4] In the present work,
we report on the reaction of the diorganotellurium oxides
R2TeO (R = Ph, p-MeOC6H4, p-Me2NC6H4) with phenol
R
R
in solution
R
R
R
R
Te
O
Te
O
R
R
O
O
Te
Te
Te
O
Te
O
Te
O
R
R
R
R
R
R
R
R
R ϭ p-MeOC6H4
R ϭ Ph
in the solid state
Scheme 1.
and o-nitrophenol, which provides access to four different
compound classes, namely diorganotellurium hydroxy pheno-
lates, diorganotellurium bis(phenolates), and tetraorganoditel-
luroxane and hexaorganotritelluroxanes bis(o-nitrophenolates).
The reactivity of the Te=O double bond sharply contrasts that
© CSIRO 2008
10.1071/CH07329
0004-9425/08/030172

The Reactivity of Diorganotellurium Oxides Towards Phenol and o-Nitrophenol
173
O
ϩ n PhOH
Te
O1
R
R
H1
C10
n ϭ 1
n ϭ 2
ϪH2O
Te1
OH
Te
OPh
Te
R
R
R
R
C20
OPh
OPh
C30
1 R ϭ Ph
2 R ϭ p-MeOC6H4
3 R ϭ p-Me2NC6H4
4 R ϭ Ph
5 R ϭ p-MeOC6H4
6 R ϭ p-Me2NC6H4
O2
Scheme 2.
of most light p-block element oxides that have polar E–O
double bonds (e.g., Ph3PO, Ph3AsO, Ph2SO, Ph2SeO), which
form hydrogen-bonded complexes with phenol and related
compounds.[5] A few diorganotellurium dialcoholates, such as
Ph2Te(OMe)2, had been prepared previously by metathesis reac-
tions, however, their characterization remained incomplete at the
time.[6] During the course of this work, Srivastava et al. reported
on tetramethylditelluroxane bis(o,p,oꢀ-trinitrophenolate), which
was fully characterized by X-ray crystallography.[7]
Fig. 1. Molecular structure of (p-MeOC6H4)2Te(OPh)OH (2) showing
30% probability displacement ellipsoids and the crystallographic num-
bering scheme. Symmetry operation used to generate equivalent atoms:
a = x, 0.5 − y, −0.5 + z. Selected bond parameters [Å, ◦]: Te1–O1 1.980(4),
Te1–C20 2.102(6), Te1–C10 2.113(5), Te1–O2 2.209(4), O1–H1 0.69(8),
H1· · ·O2a 2.05(8), O1· · ·O2a 2.733(6), O1–Te1–C20 87.5(2), O1–Te1–
C10 89.3(2), C20–Te1–C10 96.9(2), O1–Te1–O2 168.6(2), C20–Te1–O2
82.6(2), C10–Te1–O2 86.1(2), O1–H1–O2a 175(8).
Results and Discussion
Synthetic Aspects and Structural Characterization
The reaction of the diorganotellurium oxides, R2TeO (R = Ph,
p-MeOC6H4, p-Me2NC6H4), with one and two equivalents
of phenol, PhOH, in refluxing toluene produced diorgano-
tellurium hydroxy phenolates R2Te(OH)OPh (1, R = Ph; 2,
R = p-MeOC6H4; 3, R = p-Me2NC6H4) and diorganotellurium
bis(phenolates) R2Te(OPh)2 (4, R = Ph; 5, R = p-MeOC6H4;
6, R = p-Me2NC6H4), respectively, as colourless crystalline or
microcrystalline compounds in high yields (Scheme 2).
O1a
C10
Te1
The molecular structures of (p-MeOC6H4)2Te(OH)OPh (2),
Ph2Te(OPh)2 (4), and (p-Me2NC6H4)2Te(OPh)2 (6) are shown
in Figs 1–3. Selected crystal and refinement data are collected in
Table 1 and selected bond parameters are listed in the captions
of the figures. Bearing in mind the sterically active lone pair,
the spatial arrangement around the Te atoms is best described
as distorted trigonal bipyramidal. Consistent with Bent’s rule,
the equatorial positions are occupied by two C atoms and the
lone pair, whereas the more electronegative O atoms are sit-
uated in the axial positions. In compounds 4 and 6, the Te
atoms lie across crystallographic centres of inversion. As often
observed for hypervalent main group compounds with trigo-
nal bipyramidal structures,[8] the axial Te–O bond lengths of
2 (1.980(4), 2.209(4) Å) are somewhat different, whereas those
of 4 (2.074(2) Å) and 6 (2.111(2) Å) are equal owing to the
centrosymmetry. The Te–O bond lengths of 2, 4, and 6 com-
pare well with those found for the (p-MeOC6H4)2TeO polymer
(2.025(2) and 2.100(2) Å).[2] It has previously been proposed
that π-electron delocalization might be operative in organotel-
lurium compounds that contain p-dimethylaminophenyl groups
and that besides an aromatic resonance structure (A), a second
quinoidresonancestructure(B)maycontributetothedescription
of the electron distribution (Scheme 3).[9]
C10a
O1
C20
Fig. 2. Molecular structure of Ph2Te(OPh)2 (4) showing 30% probabil-
ity displacement ellipsoids and the crystallographic numbering scheme.
Symmetry operation used to generate equivalent atoms: a = −x, y, 1.5 − z.
Selected bond parameters [Å, ◦]:Te1–O1 2.074(2),Te1–C10 2.106(4), C10–
C15 1.373(5), C10–C11 1.385(5), C15–C14 1.380(5), C14–C13 1.382(5),
C13–C12 1.379(6), C12–C11 1.376(5), O1–Te1–O1a 166.0(2), O1–Te1–
C10a 84.9(1), O1–Te1–C10 86.0(1), C10–Te1–C10a 98.2(2).
In an effort to evaluate if quinoid π-electron delocalization
is operative in 6, the quinoid character Q has been calcu-
lated from the C–C bond lengths and compared with that
of 4.[10] For Ph2Te(OPh)2 (4) Q is 0.003 Å, which indicates

174
J. Beckmann, J. Bolsinger, and A. Duthie
sidebands, which have been analyzed using the Herzfeld Berger
approach.[12] For all compounds except 5, whose signal was
too broad, the three independent tensor components have been
obtained. The absolute anisotropy of 1–6 varies between ζ 292
and 619, whereas the asymmetry ranges from η 0.30 to 0.80.
Compounds 1–6 are reasonably soluble in moderately polar
solvents, such as toluene and chloroform. The 125Te NMR spec-
tra (CDCl3) reveal sharp resonances for the diorganotellurium
hydroxo phenolates R2Te(OH)OPh at δ 1035.8 (1, R = Ph),
1038.5 (2, R = p-MeOC6H4), and 1056.0 (3, R = p-Me2NC6H4)
and for the diorganotellurium bis(phenolates) R2Te(OPh)2 at δ
1067.0 (4, R = Ph), 1074.6 (5, R = p-MeOC6H4), and 1102.8 (6,
R = p-Me2NC6H4), which are low-field shifted compared with
the 125Te NMR chemical shifts of the corresponding diorgano-
tellurium dichlorides Ph2TeCl2 (δ 919.7), (p-MeOC6H4)2TeCl2
(δ 933.1), and (p-Me2NC6H4)2TeCl2 (δ 960.9).[13]
O1a
C10a
C10
Te1
C20
O1
Thereactionofthediorganotelluriumoxides, R2TeO (R = Ph,
p-MeOC6H4, p-Me2NC6H4), with o-nitrophenol in reflux-
ing toluene proceeds with condensation and produces the
tetraorganoditelluroxane
bis(o-nitrophenolates)
(RꢀO)R2
TeOTeR2(ORꢀ) (7, R = p-MeOC6H4; 8, R = p-Me2NC6H4;
Rꢀ = o-NO2C6H4) and the hexaphenyltritelluroxane bis(o-
nitrophenolate) (RꢀO)Ph2TeOTePh2OTePh2(ORꢀ) (9, Rꢀ = o-
NO2C6H4) as yellow and orange microcrystalline solids in very
good yield (Scheme 4). The yields of 7 and 8 are best when the
ratio of the o-nitrophenol and diorganotellurium oxides R2TeO
(R = p-MeOC6H4, p-Me2NC6H4) is 1:2. At a ratio of 1:1 the
yield of 8 is substantially lower and a second unaccounted prod-
uct is also obtained, which could not be purified. In case of 7
only a mixture of inseparable products is obtained.
Fig. 3. Molecular structure of (p-Me2NC6H4)2Te(OPh)2 (6) showing
30% probability displacement ellipsoids and the crystallographic numbering
scheme. Symmetry operation used to generate equivalent atoms: a = 1 − x,
0.5 − y, z. Selected bond parameters [Å, ◦]: Te1–C10 2.096(3), Te1–O1
2.111(2), C13–C12 1.402(4), C13–C14 1.407(5), C10–C11 1.388(4), C10–
C15 1.387(4), C12–C11 1.381(4), C14–C15 1.379(4), C13–N1 1.355(3),
C10–Te1–C10a 95.0(2), C10–Te1–O1 86.6(1), C10–Te1–O1a 89.2(1), O1–
Te1–O1a 173.8(1).
Regardless of the stoichimetric ratio the reaction of diphenyl-
tellurium oxide, Ph2TeO, with o-nitrophenol gives rise to
the formation of hexaphenyltritelluroxane bis(o-nitrophenolate)
(RꢀO)Ph2TeOTePh2OTePh2(ORꢀ)(9, Rꢀ = o-NO2C6H4)thatwas
isolated in good yields (Scheme 4).
almost no contribution of the resonance structure B. For (p-
Me2NC6H4)2Te(OPh)2 (6) the parameter Q is 0.016 Å, which
is approximately half the value observed for p-H2NC6H4NO2
(0.032 Å). The idea of a bipolar resonance structure contribu-
tion is also supported by the C13–N1 bond length of 1.355(3) Å,
which is significantly shorter than the expected value (d(C sp2–
N sp3) = 1.44–1.45 Å). However, the Te1–C10 bond length of 6
(2.096(3) Å) is only 0.010 Å shorter than that of 4 (2.106(4) Å),
which points to a disruption of the π-electron delocalization
and to a poor or no involvement of the Te atom. Like the (p-
MeOC6H4)2TeO polymer,[2] the solid-state structures of 2, 4,
and 6 lack any secondary Te–O interactions. In the crystal lat-
tice, (p-MeOC6H4)2Te(OH)OPh (2) is associated by hydrogen
bonding, whereby the phenolate group of an adjacent molecule
acts as the hydrogen acceptor. The donor acceptor O1· · ·O2a
distance of 2.733(6) Å is indicative of a weak hydrogen bridge
(symmetry code: a = x, 0.5 − y, −0.5 + z).[11] The infrared (IR)
spectra (KBr pellets) of the diorganotellurium hydroxo pheno-
lates R2Te(OH)OPh exhibit bands at 3410 (1, R = Ph), 3388
(2, p-MeOC6H4), and 3414 cm−1 (3, R = p-Me2NC6H4) that
are assigned to OH stretching vibrations. The position of these
bands is consistent with weak hydrogen bonding. Compounds
1–6 have been characterized by 125Te MAS NMR spectroscopy.
All compounds give rise to a single resonance between δiso
930 and 1184. Notably, the variation of the organic substituents
in R2Te(OH)OPh and R2Te(OPh)2 (R = Ph: δiso 1046 (1) and
1111(4); R = p-MeOC6H4: δiso 991 (2) and 930 (5); R = p-
Me2NC6H4: δiso 1028 (3) and 1184 (6)) seems to have a larger
effect on the 125Te MAS NMR chemical shift than the num-
ber of phenolate groups. Owing to the rather large chemical
shift anisotropy, the centre bands are accompanied by spinning
The formation of tetraorganoditelluroxanes and hexaorgano-
tritelluroxanes rather than diorganotellurium hydroxy o-
nitrophenolate or diorganotellurium bis(o-nitrophenolates) is
tentatively explained by the coordination strength, which is
greater for the phenolate ion than the o-nitrophenolate ion
owing to the more effective delocalization of the negative charge
across the aromatic π-system. The molecular and crystal struc-
tures of (RꢀO)R2TeOTeR2(ORꢀ) (7, R = p-MeOC6H4; Rꢀ = o-
NO2C6H4) and (RꢀO)Ph2TeOTePh2OTePh2(ORꢀ) (9, Rꢀ = o-
NO2C6H4) are shown in Figs 4–7. Selected crystal and refine-
ment data are collected in Table 1 and selected bond param-
eters are listed in the caption of the figures. Like in com-
pounds 2, 4, and 6, the spatial arrangement (first coordination
sphere) around the Te atoms of 7 and 9 is distorted trigo-
nal bipyramidal with the expected occupancy of the ligand
atoms. However, unlike the mononuclear compounds, the axial
distortion of dinuclear species 7 is more pronounced, with
the Te1–O1 and Te2–O1 bond lengths of the oxygen bridge
(2.018(2) and 2.024(2) Å) being somewhat shorter than the
Te1–O4 and Te2–O2 bond lengths for the o-nitrophenolate
coordination (2.236(2) and 2.244(2) Å). However, the mean
Te–O distance of the o-nitrophenolate anions to the Te atoms
of 7 (av. 2.240 (6) Å) is still shorter than those of related
tetraorganoditelluroxanes that contain other oxygen anions,
e.g., (RO)Me2TeOTeMe2(OR) (av. 2.365(3) Å; R = o,p,oꢀ-
trinitrophenyl),[7] (F3CCO2)Ph2TeOTePh2(O2CCF3)·0.5H2O
(av. 2.352(10) Å),[14] (Ph2PO2)R2TeOTeR2(O2PPh2)·2Ph2PO2H
(2.440(2) Å;
R = p-MeOC6H4),[15]
(NO3)Ph2TeOTePh2

The Reactivity of Diorganotellurium Oxides Towards Phenol and o-Nitrophenol
175

176
J. Beckmann, J. Bolsinger, and A. Duthie
12
14
11
15
OPh
Te
OPh
10
Ϫ
Te
13
ϩ
N
N
N
N
OPh
OPh
A
B
Scheme 3.
O
m
ϩ n RЈOH
Te
R
R
N1
N2b
O7
O6
O8b
n ϭ m ϭ 1
ϪH2O
m ϭ 3, n ϭ 2
O4
ϪH2O
O9b
Te1
R
R
R
R
R
O
ORЈ
O
R
R
R
Te
Te
Te
R
O1
O6a
Te
Te
RЈO
O
R
RЈO
ORЈ
Te2
7
8
R = p-MeOC6H4
R = p-Me2NC6H4
9
R ϭ Ph
O9
O8
O2
RЈ ϭ o-O2NC6H4
N1a
N2
O7a
Scheme 4.
Fig. 5. Perspective view of (RꢀO)R2TeOTeR2(ORꢀ) (7, R = p-MeOC6H4,
Rꢀ = o-O2NC6H4) showing the supramolecular association of individual
molecules by secondary Te· · ·O interactions. Symmetry operation used
to generate equivalent atoms: a = 1 − x, 1 − y, −z, b = 1 − x, 2 − y, −z.
Selected bond parameters [Å]: Te1· · ·O8b 3.078(5), Te1· · ·O9b 3.414(6),
Te2· · ·O6a 3.671(6), Te2· · ·O7a 3.341(5), Te2· · ·O9b 3.303(9).
C40
C20
Te1
O1
Te atoms (Te2–O1 1.963(2) Å/Te2–O3 2.310(2) Å, Te3–O2
1.945(2) Å/Te3–O4 2.397(2) Å) than at the central Te atom
(Te1–O1 2.082(2) Å/Te1–O2 2.102(2) Å). Besides the primary
coordination sphere, the crystal structures of 7 and 9 reveal
several secondary Te· · ·O interactions (Figs 5 and 7) that are
shorter or slightly longer than the sum of the van der Waals radii
(3.58 Å). For the tetraorganoditelluroxane 7 these contacts are a
result of the intermolecular coordination of two adjacent nitro
groups that increase the coordination number of Te1 and Te2
by 2 and 3 secondary contacts, respectively. In hexaorganotritel-
luroxane 9 the secondary interactions from the coordination of
two nitro groups and one phenolate group increase the coordi-
nation number of Te2 and Te3 by 2 and of Te1 by 3. Attempts
were also made to characterize compounds 7–9 by 125Te MAS
NMR spectroscopy; however, a reasonable spectrum was only
obtained for 9, which shows three signals of equal intensity at
δiso 1060, 1137, and 1176. The large chemical shift anisotropy
was also investigated by an Herzfeld Berger analysis.[12] The
absolute anisotropies of the three signals being ζ 332, 366, and
373 are very similar, whereas the asymmetry (η 0.00) of the
central tellurium (δiso 1060) is significantly lower than the outer
Te atoms (η 0.70 and 0.90). In CDCl3 solution, the tetraorgano-
ditelluroxanes 7 and 8 give rise to broad 125Te NMR resonances
at δ 1098.3 and 1117.0, whereas the hexaorganotritelluroxane 9
shows only one broad signal at δ 1095.3. The single broad 125Te
NMR signal for 9 is indicative of a dynamic process that com-
promises the configurational stability of theTe atoms in solution.
C10
Te2
O2
C30
O4
C70
Fig. 4. Molecular structure of (RꢀO)R2TeOTeR2(ORꢀ) (7, R = p-
MeOC6H4, Rꢀ = o-O2NC6H4) showing 30% probability displacement ellip-
soids and the crystallographic numbering scheme. Selected bond parameters
[Å, ◦]: Te1–O1 2.018(2), Te1–C20 2.111(3), Te1–C10 2.131(3), Te1–O4
2.236(2), Te2–O1 2.024(2), Te2–C40 2.117(3), Te2–C30 2.128(3), Te2–
O2 2.244(2), O1–Te1–C20 91.5(1), O1–Te1–C10 89.5(1), C20–Te1–C10
95.2(1), O1–Te1–O4 173.0(1), C20–Te1–O4 82.5(1), C10–Te1–O4 87.4(1),
O1–Te2–C40 88.0(1), O1–Te2–C30 92.6(1), C40–Te2–C30 97.0(1), O1–
Te2–O2 171.4(1), C40–Te2–O2 86.0(1), C30–Te2–O2 82.0(1),Te1–O1–Te2
115.7(1).
(NO3) Ph2Te(OH)NO3 (av.Te–O: 2.452(3) Å),[16] and (F3CSO3)
R2TeOTeR2(O3SCF3) (av. 2.619(6) Å; R = p-MeOC6H4).[15]
The molecular structure of hexaorganotritelluroxane 9 and the
ligand occupancies around the Te atoms resembles that of
7. The axial distortion is more pronounced at the terminal

The Reactivity of Diorganotellurium Oxides Towards Phenol and o-Nitrophenol
177
O4
O3
Te3
C50
Te2
C40
C60
Te1
O1
C30
O2
C20
C10
Fig. 6. Molecular structure of (RꢀO)Ph2TeOTePh2OTePh2(ORꢀ) (9, Rꢀ = o-O2NC6H4) showing 30% probability displacement
ellipsoids and the crystallographic numbering scheme. Selected bond parameters [Å, ◦]: Te1–O1 2.082(2), Te1–O2 2.102(2), Te1–
C10 2.114(3), Te1–C20 2.133(3), Te2–O1 1.963(2), Te2–C40 2.113(3), Te2–C30 2.129(3), Te2–O3 2.310(2), Te3–O2 1.945(2),
Te3–C60 2.117(3), Te3–C50 2.126(3), Te3–O4 2.397(2), O1–Te1–O2 167.5(1), O1–Te1–C10 86.2(1), O2–Te1–C10 84.9(1),
O1–Te1–C20 87.2(1), O2–Te1–C20 85.8(1), C10–Te1–C20 100.4(1), O1–Te2–C40 90.6(1), O1–Te2–C30 88.8(1), C40–Te2–
C30 96.4(1), O1–Te2–O3 171.3(1), C40–Te2–O3 82.3(1), C30–Te2–O3 86.9(1), O2–Te3–C60 91.6(1), O2–Te3–C50 91.0(1),
C60–Te3–C50 96.9(1), O2–Te3–O4 172.6(1), C60–Te3–O4 81.5(1), C50–Te3–O4 87.1(1), Te3–O2–Te1 119.8(1), Te2–O1–Te1
123.1(1).
O5c
O7a
N1c
O6c
Te3a
O4a
O3
O2a
O1
Te2
Te1
O2
Te1a
Te2a
O1a
O6b
N1b
O3a
O4
Te3
O7
O5b
Fig. 7. Perspective view of (RꢀO)Ph2TeOTePh2OTePh2(ORꢀ) (9, Rꢀ = o-O2NC6H4) showing the supramolecular associ-
ation of individual molecules by secondary Te· · ·O interactions. Symmetry operation used to generate equivalent atoms:
a = 1 − x, 1 − y, 1 − z, b = −x, 1 − y, 1 − z. Selected bond parameters [Å]: Te2· · ·O7a 3.358(6), Te2· · ·O6b 3.153(8),
Te1· · ·O6b 3.197(4), Te1· · ·O5b 3.449(4), Te1· · ·O7a 3.592(5), Te3· · ·O4a 3.168(6), Te3· · ·O5b 3.792(8).
The number of 13C NMR resonances of 9 is indicative of only
one phenyl group (see Experimental section).
by 125Te NMR spectroscopy. The detected 125Te signals at
δ 1055.6, 1062.8, and 1082.0, have been assigned to the
tetraorganoditelluroxanes (PhO)R2TeOTeR2(OPh) (10, R = Ph;
11, R = p-MeOC6H4; 12, R = p-Me2NC6H4) (Scheme 5).
Removal of the solvent afforded moisture sensitive oils, whose
reaction with water from the air upon standing furnished
solid diorganotellurium hydroxy phenolates R2Te(OH)OPh (1,
R = Ph; 2, R = p-MeOC6H4; 3, R = p-Me2NC6H4) in nearly
quantitative yields (Scheme 5).
Insertion and Redistribution Reactions
The equimolar reaction of the diorganotellurium oxides R2TeO
(R = Ph, p-MeOC6H4, p-Me2NC6H4) with diorganotellurium
bis(phenolates) R2Te(OPh)2 (4, R = Ph; 5, R = p-MeOC6H4; 6,
R = p-Me2NC6H4) in CDCl3 at 50◦C under rigorous exclusion
of moisture provided colourless solutions that were investigated

178
J. Beckmann, J. Bolsinger, and A. Duthie
OPh
Te
O
R
R
R
R
O
ϩ
R
R
Te
Te
Te
PhO
OPh
R
R
OPh
4
5
6
R ϭ Ph
R ϭ p-MeOC6H4
R ϭ p-Me2NC6H4
10 R ϭ Ph
11 R ϭ p-MeOC6H4
12 R ϭ p-Me2NC6H4
H2O
C10
C30
OH
R
O1
Te1
Te2
Te
2
R
Cl1
Cl2
OPh
1
2
3
R ϭ Ph
R ϭ p-MeOC6H4
R ϭ p-Me2NC6H4
C20
C40
Scheme 5.
Cl
Te
Cl
OPh
Te
Cl
R
R
R
R
ϩ
Te
2
R
R
OPh
OPh
4
R ϭ Ph
13 R ϭ Ph
5
6
R ϭ p-MeOC6H4
R ϭ p-Me2NC6H4
14 R ϭ p-MeOC6H4
15 R ϭ p-Me2NC6H4
Fig. 8. Molecular structure of ClR2TeOTeR2Cl (17, R = p-MeOC6H4)
showing 30% probability displacement ellipsoids and the crystallographic
numbering scheme. Selected bond parameters [Å, ◦]: Te1–O1 1.975(3),
Te1–C20 2.098(4), Te1–C10 2.108(4), Te1–Cl1 2.736(1), Te2–O1 1.995(3),
Te2–C30 2.082(4), Te2–C40 2.111(4), Te2–Cl2 2.720(1), O1–Te1–
C20 89.0(1), O1–Te1–C10 90.7(1), C20–Te1–C10 96.2(2), O1–Te1–
Cl1 175.5(1), C20–Te1–Cl1 87.4(1), C10–Te1–Cl1 92.3(1), O1–Te2–
C30 87.5(1), O1–Te2–C40 90.7(1), C30–Te2–C40 99.1(2), O1–Te2–
Cl2 175.0(1), C30–Te2–Cl2 87.6(1), C40–Te2–Cl2 90.7(1), Te1–O1–Te2
121.0(1).
H2O
Ϫ2 PhOH
Cl
R
R
O
R
O
R
R
ϩ
Te
R
Te
Te
Te
Cl
Cl
R
R
Cl
16 R ϭ Ph
17 R ϭ p-MeOC6H4
18 R ϭ p-Me2NC6H4
the redistribution of equimolar amounts of diorganotellurium
oxidesR2TeO (R = Ph, p-MeOC6H4, p-Me2NC6H4)andthecor-
responding diorganotellurium dichlorides R2TeCl2 (Scheme 6).
Compounds 16–18 were obtained as microcrystalline solids. It
is worth mentioning that several tetraorganotelluroxane dichlo-
rides have been obtained previously by the incomplete hydrolysis
of diaryltellurium dihalides, however, their characterization
remained incomplete at that time.[17]
The molecular and crystal structures of ClR2TeOTeR2Cl
(17, R = p-MeOC6H4; 18, R = p-Me2NC6H4) are shown in
Figs 8–10. Compound 17 cocrystallizes with a molecule of phe-
nol, which fills a void in the crystal lattice. Selected crystal
and refinement data are collected in Table 1 and selected bond
parameters are listed in the captions of the figures. The Te atoms
also show trigonal bipyramidal geometries with a marked dis-
tortion of the axial ligands.[7] Thus, the average Te–Cl bond
length of 17 and 18 being 2.722(1) is slightly longer than that
observed for Ph2TeCl2 (2.506(3) Å).[18] The average Te–O bond
length of 1.980(2) Å is slightly shorter than the ‘standard’ Te–
O single bond of 4 (2.074(2) Å) and of [(p-MeOC6H4)2TeO]n
(2.063(2) Å).[2] The Te–O–Te angle of 17 is 121.0(1), and
is comparable with those of 7 (115.7(1)◦), 9 (119.8(1)◦),
(123.1(1)◦), and other tetraorganoditelluroxanes.[13–15] The
Te–O–Te angle of 18 is 131.8(2)◦ and appears to be very large
for no obvious reason. Since the O1 atom of 18 is situated on a
Scheme 6.
The equimolar reaction of diorganotellurium dichlorides
R2TeCl2 (R = Ph, p-MeOC6H4, p-Me2NC6H4) with diorgano-
tellurium bis(phenolates) R2Te(OPh)2 (4, R = Ph; 5, R = p-
MeOC6H4; 6, R = p-Me2NC6H4) in CDCl3 at room temperature
for 1 h under rigorous exclusion from moisture produced equi-
librium mixtures of the starting compounds and the diorgano-
tellurium chloro phenolates R2Te(Cl)OPh (13, R = Ph; 14,
R = p-MeOC6H4; 15, R = p-Me2NC6H4) (Scheme 6).The 125Te
NMR spectra (CDCl3) of the three equilibrium mixtures reveal
signals at δ 919.7 (integral 15%; Ph2TeCl2), 1048.6 (integral
70%; 13), and 1067.0 (integral 15%; 4), at δ 933.1 (integral
15%; (p-MeOC6H4)2TeCl2), 1060.3 (integral 70%; 14), and
1074.6 (integral 15%; 5), as well as at δ 960.9 (integral 15%;
(p-Me2NC6H4)2TeCl2), 1091.1 (integral 70%; 15), and 1102.8
(integral 15%; 6). Longer reaction times had no influence on
the integral ratios. In all cases, the removal of the solvent leaves
a colourless sensitive oil, whose reaction with moist air gives
rise to the formation of solid tetraorganotelluroxane dichlo-
rides ClR2TeOTeR2Cl (16, R = Ph; 17, R = p-MeOC6H4; 18,
R = p-Me2NC6H4) and phenol (Scheme 6).A more rational syn-
thesis of the tetraorganotelluroxane dichlorides 16–18 involves

The Reactivity of Diorganotellurium Oxides Towards Phenol and o-Nitrophenol
179
(p-MeOC6H4)2TeCl2 (δiso 979.4/1001.7), (p-Me2NC6H4)2TeCl2
(δiso 969.0),[13] Ph2TeO (δiso 1133/1103), (p-MeOC6H4)2TeO
(δiso 903),[2] and (p-Me2NC6H4)2TeO (δiso 857.5),[20] respec-
tively. The 125Te MAS NMR of 16 and 18 were suitable for a
Herzfeld Berger tensor analysis.[12] The absolute anisotropies of
ζ 277 and 344 and the asymmetries η 0.45 and 0.25 are compa-
rable with those of the starting materials.[13] Compounds 16–18
are rather poorly soluble in most organic solvents, a fact that
may be attributable to the strong supramolecular association by
secondary contacts. The 125Te NMR spectra (CDCl3) of 17 and
18 reveal one signal at δ 1092.9 and 1072.0, whereas no signal
could be obtained for 16 because of the poor solubility.
C20a
C10
O1
Te1
Te1a
Cl1
Cl1a
Conclusion
C20
C10a
The reactivity of diorganotellurium oxides towards phenol and
o-nitrophenol is surprisingly diverse and affords diorganotel-
lurium hydroxy phenolates, diorganotellurium bis(phenolates),
tetraorganoditelluroxane bis(o-nitrophenolates), and hexa-
organotritelluroxane bis(o-nitrophenolates) depending on the
stoichiometry and the reaction conditions applied (Schemes 2
and 4). In contrast, other main group element oxides, such
as Ph3PO, Ph3AsO, Ph2SO, and Ph2SeO, which have polar
E–O double bonds form hydrogen bonded complexes with phe-
nols and related compounds.[5] The behaviour of monomeric
p-(MeOC6H4)2TeO to crystallize from solution as a polymer
(Scheme 1) is reminiscent of aqueous formaldehyde solu-
tions, which deposit polymeric paraformaldehyde upon stand-
ing. Similarly, the condensation reactions of diorganotellurium
oxides with phenol resemble the acetalization of ketones with
alcohols (Scheme 2). The reactivity of the diorganotellurium
bis(phenolates) in redistribution reactions with diorganotel-
lurium oxides and diorganotellurium dichlorides can be ratio-
nalized by the kinetic lability of the Te–O and Te–Cl bonds
under laboratory conditions (Schemes 5 and 6). We are cur-
rently seeking to combine the reactivity of diorganotellurium
oxides towards phenols and with the ability to absorb carbon
dioxide.[4] The goal of this research is the synthesis of a single
source precursor that may be able to liberate diphenyl carbonate
(DPC) upon heating.
Fig. 9. Molecular structure of ClR2TeOTeR2Cl (18, R = p-Me2NC6H4)
showing 30% probability displacement ellipsoids and the crystallographic
numbering scheme. Symmetry operation used to generate equivalent atoms:
a = 1 − x, y, 0.5 − z. Selected bond parameters [Å, ◦]:Te1–O1 1.970(2),Te1–
C10 2.093(4), Te1–C20 2.124(4), Te1–Cl1 2.716(1), O1–Te1–C10 85.2(1),
O1–Te1–C20 88.9(1), C10–Te1–C20 96.0(1), O1–Te1–Cl1 172.8(1), C10–
Te1–Cl1 87.7(1), C20–Te1–Cl1 93.0(1), Te1–O1–Te1a 131.8(2).
Cl1c
Cl1b
Cl1a
Cl1
O1
Te1a
Te1
Fig. 10. Perspective view on ClR2TeOTeR2Cl (18, R = p-Me2NC6H4)
showing the supramolecular association of individual molecules by sec-
ondary Te· · ·Cl interactions. Symmetry operation used to generate equiv-
alent atoms: b = 1 − x, 1 − y, 1 − z, c = x, 1 − y, −0.5 + z. Selected bond
parameters [Å]: Te1· · ·Cl1b 3.789(5), Te1· · ·Cl1c 3.618(13).
Experimental
General
ThediorganotelluriumoxidesR2TeO (R = Ph,[2] p-MeOC6H4,[3]
p-Me2NC6H4[20]) have been prepared according to literature
procedures. The 1H, 13C, and 125Te NMR spectra were recorded
using a Jeol GX 270 and a Varian 300 Unity Plus spec-
trometers and are referenced to SiMe4 (1H, 13C) and Me2Te
crystallographic centre of inversion the related angle should be
interpreted with caution. Compound 17 and 18 are associated
by secondaryTe· · ·Cl interactions that link individual molecules
and gives rise to an infinite coordination polymer in the crystal
lattice. In this way the solid-state structures of 17 and 18 differ
from that of IR2TeOTeR2I (R = p-MeOC6H4), which adopts a
dimeric structure.[19]
The supramolecular motifs of 17 and 18 are very similar
for both compounds and are shown for 18 in Fig. 10. The
secondary Te· · ·Cl of 3.789(5) and 3.618(13) Å increase the
coordination number of the Te atom by 2. The tetraorganotel-
luroxanes ClR2TeOTeR2Cl (16, R = Ph; 17, R = p-MeOC6H4;
18, R = p-Me2NC6H4) were characterized by 125Te MAS NMR
spectroscopy. The spectra exhibit a single centre band at δiso
1149, 1154, and 1153, which are high-field shifted by com-
parison with their parent compounds Ph2TeCl2 (δiso 900.0),
(
125Te). The 125Te CP MAS NMR spectra were obtained at
126.26 MHz using a JEOL Eclipse Plus 400 MHz NMR spec-
trometer equipped with a 6 mm rotor operating at spinning
frequencies between 8 and 10 kHz. A 30 s recycle delay was
used and typically 5000 to 10000 transitions were accumulated
to obtain signal-to-noise ratios adequate for the tensor analyses.
The isotropic chemical shifts δiso were determined by com-
parison of two acquisitions measured at sufficiently different
spinning frequencies and were referenced against Me2Te using
solid Te(OH)6 as the secondary reference (δiso 692.2/685.5).
The tensor analyses were performed using DMFit 2002[21]
and are based on relative intensities of the spinning side-
bands. Definitions δiso (ppm) = −σiso = −(σ11 + σ22 + σ33)/3;
ζ (ppm) = σ33 − σiso, and η = (σ22 − σ11)/(σ33 − σiso) where

180
J. Beckmann, J. Bolsinger, and A. Duthie
σ11, σ22, and σ33 (ppm) are the principal tensor compo-
nents of the shielding anisotropy (SA), and are sorted as
follows |σ33 − σiso| > |σ11 − σiso| > |σ22 − σiso|. Microanalyses
were obtained from a Vario EL elemental analyzer.
(Found: C 61.47, H 4.27. Calc. for C24H20O2Te (468.01):
C 61.59, H 4.31%.)
Compound 5: 0.48 g, 0.91 mmol, 91% yield, mp 194–196◦C.
δH (CDCl3) 8.09 (d, 4H, p-TeoC6H4OMe), 7.17 (m, 4H, OmPh),
7.04 (d, 4H, p-TemC6H4OMe), 6.83 (t, 2H, OpPh), 6.73 (d, 4H,
OoPh), 3.83 (s, 6H, OMe). δC (CDCl3) 162.0 (OiPh), 160.4 (p-
TepC6H4OMe), 134.3 (p-TeoC6H4OMe), 129.6 (OmPh), 126.8
(p-TeiC6H4OMe), 120.5 (OoPh), 119.9 (OpPh), 115.3 (p-
TemC6H4OMe), 55.4 (OMe). δTe (CDCl3) 1074.6. 125Te CP
MAS NMR δiso: 930 (broad). (Found: C 59.34, H 4.66. Calc.
for C26H24O4Te (528.07): C 59.14, H 4.58%.)
Synthesis of Diorganotellurium Hydroxy Phenolates 1–3
A mixture of the appropriate R2TeO (0.30 g for R = Ph, 0.36 g
for R = p-MeOC6H4, 0.38 g for R = p-Me2NC6H4, 1.00 mmol)
and phenol (0.096 g, 1.0 mmol) was dissolved in toluene (50 mL)
and stirred for 12 h. The solvent was removed under vacuum to
∼25 mL and the remaining clear solution was cooled to 4◦C.
Within 24 h colourless crystals formed that were collected by
filtration.
Compound 6: 0.49 g, 0.88 mmol, 88% yield, mp 175–
178◦C (turns red). δH (CDCl3) 7.99 (d, 4H, p-TeoC6H4NMe2),
7.18 (m, 4H, OmPh), 6.78 (m, 10H, p-TemC6H4NMe2/OoPh/
OpPh), 3.00 (s, 12H, NMe2). δC (CDCl3) 160.9 (OiPh), 151.9
(p-TepC6H4NMe2), 133.7 (p-TeoC6H4NMe2), 129.4 (OmPh),
121.0 (p-TeiC6H4NMe2), 120.6 (OoPh), 119.4 (OpPh), 112.7
(p-TmC6H4NMe2), 40.0 (NMe2). δTe (CDCl3) 1102.8. 125Te
CP MAS NMR δiso: 1184, ζ: −619, η: 0.30 (σ11: −782, σ22:
−967, σ33: −1803). (Found: C 60.61, H 5.22, N 5.02. Calc. for
C28H30N2O2Te (554.15): C 60.69, H 5.46, N 5.06%.)
Compound 1: 0.33 g, 0.84 mmol, 84% yield, mp 124–128◦C
(softening at 121◦C). δH (CDCl3) 7.98 (d, 4H, TeoPh), 7.45
(m, 6H, TemPh/TepPh), 7.17 (t, 2H, OmPh), 6.78 (t, 1H, OpPh),
6.59 (d, 2H, OoPh). δC (CDCl3) 161.4 (OiPh), 137.7 (TeiPh),
132.4 (TeoPh), 130.7 (TepPh), 129.4 (TemPh), 129.3 (OmPh),
120.4 (OoPh), 118.3 (OpPh). δTe (CDCl3) 1035.8. 125Te CP MAS
NMR δiso: 1046, ζ: 372, η: 0.50 (σ11: −1325, σ22: −1139, σ33:
−674). νmax (KBr)/cm−1 ν(OH) 3410. (Found: C 55.33, H 3.88.
Calc. for C18H16O2Te (391.92): C 55.16, H 4.11%.)
Synthesis of Tetraorganoditelluroxane
Bis(o-nitrophenolates) 7 and 8
Compound 2: 0.31 g, 0.69 mmol, 69% yield, mp 141–146◦C
(softening at 132◦C). δH (CDCl3) 7.82 (d, 4H, p-TeoC6H4OMe),
7.10 (t, 2H, OmPh), 6.91 (d, 4H, p-TemC6H4OMe), 6.72
(t, 1H, OpPh), 6.52 (d, 2H, OoPh), 3.80 (s, 6H, OMe).
δC (CDCl3) 161.9 (OiPh), 161.5 (p-TepC6H4OMe), 133.8
(p-TeoC6H4OMe), 129.3 (OmPh), 128.1 (p-TeiC6H4OMe),
120.2 (OoPh), 118.0 (OpPh), 114.8 (p-TemC6H4OMe), 55.3
(OMe). δTe (CDCl3) 1038.5. 125Te CP MAS NMR δiso: 991,
ζ: 292, η: 0.80 (σ11: −1254, σ22: −1020, σ33: −699). νmax
(KBr)/cm−1 ν(OH) 3388. (Found: C 53.47, H 4.26. Calc. for
C20H20O4Te (451.97): C 53.15, H 4.46%.)
A mixture of the appropriate R2TeO (0.35 g for R = p-
MeOC6H4, 0.39 g for R = p-Me2NC6H4, 1.0 mmol) and o-
nitrophenol (0.28 g, 2.0 mmol) was dissolved in toluene (80 mL)
and heated under reflux in a Dean Stark apparatus for 12 h. The
solvent was removed under vacuum and the residue was dis-
solved in CH2Cl2/diethyl ether. Within 48 h yellow (7) or orange
(8) crystals formed that were collected by filtration.
Compound 7: 0.45 g, 0.46 mmol, 92% yield, mp
116–118◦C. δH (CDCl3) 7.81 (d, 2H, o-OmC6H4NoO2), 7.71
(d, 8H, p-TeoC6H4OMe), 7.18 (t, 2H, o-OmC6H4NpO2),
6.89 (d, 8H, p-TemC6H4OMe), 6.63 (t, 2H, o-OpC6H4NO2),
6.43 (d, 2H, o-OoC6H4NmO2), 3.80 (s, 12H, OMe). δC
(CDCl3) 161.7 (p-TepC6H4OMe), 158.1 (o-OiC6H4NO2),
139.7 (o-OoC6H4NiO2), 134.9 (o-OmC6H4NpO2), 133.9
(p-TeoC6H4OMe), 128.2 (p-TeiC6H4OMe), 125.7 (o-
Compound 3: 0.38 g, 0.79 mmol, 79% yield, mp 155–
158◦C (softening at 139◦C). δH (CDCl3) 7.75 (d, 4H,
p-TeoC6H4NMe2), 7.09 (t, 2H, OmPh), 6.75–6.57 (m, 5H, p-
TemC6H4NMe2/OpPh), 6.55(d, 2H, OoPh), 2.98(s, 12H, NMe2).
δC (CDCl3) 162.4 (OiPh), 151.7 (p-TepC6H4NMe2), 133.3
(p-TeoC6H4NMe2), 129.1 (OmPh), 122.5 (p-TeiC6H4NMe2),
120.1 (OoPh), 117.3 (OpPh), 112.4 (p-TemC6H4NMe2), 40.0
OmC6H4NoO2),
123.9
(o-OpC6H4NO2),
116.9
(o-
OoC6H4NmO2), 115.0 (p-TemC6H4OMe), 55.4 (OMe). δTe
(CDCl3) 1098.3. (Found: C 49.01, H 3.63, N 2.80. Calc. for
C40H36N2O11Te2 (975.92): C 49.23, H 3.72, N 2.87%.)
(NMe2). δTe (CDCl3) 1056.0. 125Te CP MAS NMR δiso
:
1028, ζ: −355, η: 0.80 (σ11: −708, σ22: −992, σ33:
−1383). νmax (KBr)/cm−1 ν(OH) 3414. (Found: C 55.58, H
5.34, N 5.50. Calc. for C22H26N2O2Te (478.05): C 55.27,
H 5.48, N 5.86%.)
Compound 8: 0.46 g, 0.45 mmol, 90% yield, mp
119–124◦C. δH (CDCl3) 7.80 (d, 2H, o-OmC6H4NoO2), 7.67
(d, 8H, p-TeoC6H4NMe2), 7.13 (t, 2H, o-OmC6H4NpO2),
6.64 (d, 8H, p-TemC6H4NMe2), 6.56 (t, 2H, o-OpC6H4NO2),
6.42 (d, 2H, o-OoC6H4NmO2), 2.99 (s, 24H, NMe2). δC
(CDCl3) 159.0 (o-OiC6H4NO2), 151.6 (p-TepC6H4NMe2),
140.01 (o-OoC6H4NiO2), 134.1 (o-OmC6H4NpO2), 133.6 (p-
TeoC6H4NMe2), 125.6 (o-OmC6H4NoO2), 124.2 (o-
Synthesis of Diorganotellurium Bis(phenolates) 4–6
A mixture of the appropriate R2TeO (0.30 g for R = Ph, 0.36 g for
R = p-MeOC6H4, 0.38 g for R = p-Me2NC6H4, 1.0 mmol) and
phenol (0.20 g, 2.1 mmol) was dissolved in toluene (80 mL) and
heated under reflux in a Dean Stark apparatus for 12 h. The sol-
vent was removed under vacuum to ∼25 mL and the remaining
clear solution was cooled to 4◦C. Within 24 h colourless crystals
formed that were collected by filtration.
OpC6H4NO2),
122.1
(p-TeiC6H4NMe2),
115.6
(o-
OoC6H4NmO2), 112.4 (p-TemC6H4NMe2), 40.0 (NMe2). δTe
(CDCl3) 1117.0. (Found: C 51.75, H 4.55, N 8.01. Calc. for
C44H48N6O7Te2 (1028.09): C 51.40, H 4.71, N 8.17%.)
Compound 4: 0.44 g, 0.94 mmol, 94% yield, mp 144–145◦C.
δH (CDCl3) 8.26 (m, 4H, TeoPh), 7.56 (m, 6H, TemPh/TepPh),
7.24 (m, 4H, OmPh), 6.90 (t, 2H, OpPh), 6.82 (d, 4H, OoPh).
δC (CDCl3) 160.2 (OiPh), 136.3 (TeiPh), 132.8 (TeoPh), 131.3
(TepPh), 129.8 (TemPh), 129.4 (OmPh), 120.5 (OoPh), 120.1
(OpPh). δTe (CDCl3) 1067.0. 125Te CP MAS NMR δiso: 1111,
ζ: −381, η: 0.50 (σ11: −826, σ22: −1016, σ33: −1492).
Synthesis of Hexaorganotritelluroxanes
Bis(o-nitrophenolates) 9
A mixture of Ph2TeO (0.30 g, 1.0 mmol) and o-nitrophenol
(0.15 g, 1.1 mmol) was dissolved in toluene (80 mL) and heated
under reflux in a Dean Stark apparatus for 12 h. The solvent
was removed under vacuum and the residue was dissolved

The Reactivity of Diorganotellurium Oxides Towards Phenol and o-Nitrophenol
in CH2Cl2/diethyl ether. Within 48 h yellow microcrystals (9)
181
Compound 18: 0.68 g, 0.83 mmol, 83% yield, mp 213–
formed that were collected by filtration.
216◦C (dec.). δH (CDCl3) 7.78 (d, 8H, p-TeoC6H4NMe2), 6.61
(d, 8H, p-TemC6H4NMe2), 2.95 (s, 24H, NMe2). δC (CDCl3)
152.0 (p-TepC6H4NMe2), 133.9 (p-TeoC6H4NMe2), 121.3 (p-
TeiC6H4NMe2), 112.5 (p-TeoC6H4NMe2), 40.2 (NMe2). δTe
(CDCl3) 1072.0. 125Te CP MAS NMR δiso: 1153, ζ: −324, η:
0.25 (σ11: −950, σ22: −1031, σ33: −1477). (Found: C 46.32,
H 4.51, N 6.72. Calc. for C32H40Cl2N4OTe2 (822.79): C 46.71,
H 4.90, N 6.81%.)
Compound 9: 0.30 g, 0.26 mmol, 78% yield, mp 129–134◦C.
δH (CDCl3) 7.81 (d, 2H, o-OmC6H4NoO2), 7.73 (d, 12H,TeoPh),
7.37 (m, 18H, TemPh/TepPh), 7.12 (t, 2H, o-OmC6H4NpO2),
6.58 (t, 2H, o-OpC6H4NO2), 6.32 (d, 2H, o-OoC6H4NmO2).
δC (CDCl3) 159.3 (o-OiC6H4NO2), 140.7 (o-OoC6H4NiO2),
138.1 (TeiPh), 134.3 (o-OmC6H4NpO2), 132.1 (TeoPh), 130.8
(TepPh), 129.4 (TemPh), 125.8 (o-OmC6H4NoO2), 124.8
(o-OpC6H4NO2), 115.7 (o-OoC6H4NmO2). δTe (CDCl3) 1095.3
(broad). 125Te CP MAS NMR δiso: 1060, ζ: 332, η: 0.00 (σ11:
−1227, σ22: −1227, σ33: −728) 35%, δiso: 1137, ζ: 366, η: 0.70
(σ11: −1448, σ22: −1192, σ33: −771) 34%, δiso: 1176, ζ: 373,
η: 0.90 (σ11: −1530, σ22: −1195, σ33: −803) 31%. (Found:
C 49.99, H 3.14, N 2.40. Calc. for C48H38N2O8Te3 (1153.62):
C 49.97, H 3.32, N 2.43%.)
Crystallography
Single crystals suitable for X-ray crystallography were grown
from toluene (2, 4, 6), CH2Cl2/diethyl ether (7, 9), and CHCl3
(17, 18). Intensity data were collected on a Bruker SMART
1000 CCD diffractometer with graphite-monochromated MoKα
(0.7107 Å) radiation. Data were reduced and corrected for
absorption using the programs SAINT and SADABS.[22] The
structures were solved by direct methods and difference Fourier
synthesis using SHELXS-97 implemented in the programWinGX
2002.[23] Full-matrix least-squares refinements on F2, using all
data, were carried out with anisotropic displacement parameters
applied to all non-hydrogen atoms. Disorder was resolved for
O4 and C26 of 2 and C16 of 7, which were refined over two
positions with an occupancy ratio of 0.60:0.40 and over three
positionswithanoccupancyratioof0.33:0.33:0.33, respectively.
Hydrogen atoms were included in geometrically calculated
positions using a riding model and were refined isotropically.
Figures were created using DIAMOND.[24] Crystallographic
data (excluding structure factors) for the structural analyses have
been deposited with the Cambridge Crystallographic Data Cen-
tre, CCDC nos. 676121 (2), 676122 (4), 676123 (6), 676124
(7), 676125 (9), 676126 (17) and 676127 (18). Copies of
this information may be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, UK
(Fax: +44-1223-336033; Email: deposit@ccdc.cam.ac.uk or
http://www.ccdc.cam.ac.uk).
Redistribution Reaction of R2TeO and R2Te(OPh)2.
Preparation of Tetraorganoditelluroxane
Bis(phenolates) 10–12
A mixture of the appropriate R2TeO (0.30 g for R = Ph, 0.36 g
for R = p-MeOC6H4, 0.38 g for R = p-Me2NC6H4, 1.0 mmol)
and R2Te(OPh)2 (0.47 g for R = Ph, 0.53 g for R = p-MeOC6H4,
0.54 g for R = p-Me2NC6H4, 1.0 mmol) was dissolved in CHCl3
(50 mL) under a dry argon atmosphere and heated at 50◦C for
1 h. The solvent was removed under vacuum to form a brown oil.
Compound 10: δTe (CDCl3) 1055.6.
Compound 11: δTe (CDCl3) 1062.8.
Compound 12: δTe (CDCl3) 1082.0.
Redistribution Reaction of R2TeCl2 and R2Te(OPh)2.
Preparation of Tetraorganoditelluroxane Dichlorides 13–15
A mixture of the appropriate R2TeCl2 (0.35 g for R = Ph, 0.41 g
for R = p-MeOC6H4, 0.44 g for R = p-Me2NC6H4, 1.0 mmol)
and R2Te(OPh)2 (0.47 g for R = Ph, 0.53 g for R = p-MeOC6H4,
0.54 g for R = p-Me2NC6H4, 1.0 mmol) was dissolved in CDCl3
(6 mL) under a dry argon atmosphere and heated to 50◦C for 1 h.
Compound 13: δTe (CDCl3) 1048.6.
Acknowledgement
Mrs. Irene Brüdgam (Freie Universität Berlin) is thanked for the X-ray
data collection. The Deutsche Forschungsgemeinschaft (DFG) is gratefully
acknowledged for financial support.
Compound 14: δTe (CDCl3) 1060.3.
Compound 15: δTe (CDCl3) 1091.1.
References
Synthesis of Tetraorganoditelluroxane Dichlorides 16–18
[1] (a) K. Lederer, Ann. Chem. 1912, 391, 326.
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The diorganotellurium oxide R2TeO (0.30 g for R = Ph, 0.36 g
for R = p-MeOC6H4, 0.38 g for R = p-Me2NC6H4, 1.0 mmol)
and R2TeCl2 (0.35 g for R = Ph, 0.41 g for R = p-MeOC6H4,
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rately in CHCl3 (25 mL) and combined. After a short time white
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OM021024C
Compound 16: 0.61 g, 0.94 mmol, 94% yield, mp 232–
237◦C. δH (CDCl3) 7.81 (d, 8H, TeoPh), 7.36 (m, 12H,
TemPh/TepPh). 125Te CP MAS NMR δiso: 1149, ζ: −277, η: 0.45
(σ11: −948, σ22: −1073, σ33: −1426). (Found: C 44.06, H 2.73.
Calc. for C24H20Cl2OTe2 (650.52): C 44.31, H 3.10%.)
Compound 17: 0.59 g, 0.75 mmol, 75% yield, mp 198–
200◦C. δH (CDCl3) 7.74 (d, 8H, p-TeoC6H4OMe), 6.81 (d,
8H, p-TemC6H4OMe), 3.75 (s, 12H, OMe). δC (CDCl3)
161.3 (p-TepC6H4OMe), 134.7 (p-TeoC6H4OMe), 128.3 (p-
TeiC6H4OMe), 114.7 (p-TemC6H4OMe), 55.1 (OMe). δTe
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0.45 (σ11: −905, σ22: −1059, σ33: −1498). (Found: C 43.45, H
3.43. Calc. for C28H28Cl2O5Te2 (770.62): C 43.64, H 3.66%.)
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:
857.5 ppm, ζ: 206 ppm, η: 0.00, σ11: −961, σ22: −961, σ33: −652) is
[10] The quinoid character is defined as Q = [d(C10–C11) + d(C12–
C13) + d(C13–C14) + d(C15–C10)]/4 − [d(C12–C11) + d(C14–
C15)]/2. Definition range: 0 < Q < 0.138 Å. One of the largest Q val-
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most likely a polymer in the solid state. See ref. 2.
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[24] K. Brandenburg, M. Berndt, DIAMOND V2 1d, Crystal Impact.
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