Molecular stannatelluroxanes

Article abstract of DOI:10.1021/om900189s

The syntheses and structures are described of the molecular stannatelluroxanes 2,4,6-1-Bu₃C₆H₂TeO ₂Sn-tBu₂Cl (4), 8-Me₂NC₁₀H ₆TeO₂Sn-t-Bu₂Cl (S),

Full text of DOI:10.1021/om900189s

Organometallics 2009, 28, 4225–4228 4225
DOI: 10.1021/om900189s
Molecular Stannatelluroxanes
Jens Beckmann,* Jens Bolsinger, and Malte Hesse
€
Institut fu€r Chemie und Biochemie, Freie Universitat Berlin, Germany
Received March 12, 2009
Summary: The syntheses and structures are described of the
with (p-MeOC6H4)2TeO using a Sn/Te ratio of 1:1 quan-
titatively provides the hypervalent stannatelluroxane
[p-MeOC6H4)2TeOSnt-Bu2O]2 (1).2,3 Solutions of 1 rapidly
absorb gaseous CO2, giving a tetranuclear stannatelluroxane
carbonate cluster [(p-MeOC6H4)2TeOSnt-Bu2CO3]2 (2).2
Unlike most metal carbonates, 2 possesses three unevenly
long C-O bonds due to the different coordination modes
with the Sn and Te atoms, a useful characteristic when
pursuing bond activation within carbonates. While salt-like
carbonates are often thermally very stable, 2 liberates CO2
upon heating above 90 °C. These properties make 2 a
promising candidate for applications in the fixation and
activation of CO2. Another stannatelluroxane, [(p-
MeOC6H4)2Te(OSn-t-Bu2OH)2] (3), was obtained by the
reaction of (t-Bu2SnO)3 with (p-MeOC6H4)2TeO using a
Sn/Te ratio of 2:1 in the presence of moisture.3 Two mole-
cules of 3 interacted to give dimers in the solid state. The
structural characterization of 2 and 3 has revealed the
importance of hypervalent and secondary bonding for the
fixation of CO2, the degree of aggregation, and the supra-
molecular association.
molecular stannatelluroxanes 2,4,6-t-Bu3C6H2TeO2Sn-t-
Bu2Cl (4), 8-Me2NC10H6TeO2Sn-t-Bu2Cl (5), and (2,6-
Mes2C6H3Te)2O5(Sn-t-Bu2)2 (6), which were obtained by
the reaction of (t-Bu2SnO)3 with the respective aryltellurium
trichlorides RTeCl3 (R = 2,4,6-t-Bu3C6H2, 8-Me2NC10H6,
2,6-Mes2C6H3). Compounds 4-6 were characterized by mul-
tinuclear NMR spectroscopy (1H, 13C, 119Sn, 125Te), ESI-
TOF MS spectrometry, osmometric molecular weight deter-
mination, and X-ray crystallography.
Organostannoxane clusters and polymers have been the
focus of extensive research due to their fascinating struc-
tural diversity and applications in catalysis and material
science.1 Attempts to incorporate a second heavy element
into the structure of organostannoxanes are motivated by
the possibility to develop more advanced catalysts with
multiple active centers. However, so far only very few com-
pounds containingSn-O-E linkages (E = heavy element) are
known. We recently reported that the reaction of (t-Bu2SnO)3
Under the same conditions, the reaction of (t-Bu2SnO)3 with
2,6-Mes2C6H3TeCl3 proceeded with complete oxide transfer
and produced the dimeric aryltellurium oxo chloride [2,6-
Mes2C6H3Te(O)Cl]24 and t-Bu2SnCl2. At a Sn/Te ratio of 5:2
the reaction of (t-Bu2SnO)3 with 2,6-Mes2C6H3TeCl3 afforded
the tetranuclear stannatelluroxane (2,6-Mes2C6H3Te)2O5(Sn-
t-Bu2)2 (6). Further variation of the Sn/Te ratios provided no
other stannatelluroxane products. Alternatively, 6 also was
obtained by the condensation reaction of (t-Bu2SnO)3 with the
aryltellurinic acid [2,6-Mes2C6H3Te(O)OH]2. Compounds 4-6
were isolated as colorless crystals in high yields and are rare
examples of molecular oxides incorporating two heavy main
group elements.
In an effort to obtain deeper insight into the formation
of stannatelluroxanes and their ability to absorb CO2, we
have now studied the reaction of di-tert-butyltin oxide with
known aryltellurium trichlorides at various stoichiometric
ratios (Scheme 1). The reaction of (t-Bu2SnO)3 with 2,4,6-t-
Bu3C6H2TeCl3 and 8-Me2NC10H6TeCl3, respectively, using a
Sn/Te ratio of 2:1 exclusively provided the dinuclear sta-
nnatelluroxanes 2,4,6-t-Bu3C6H2TeO2Snt-Bu2Cl (4) and 8-
Me2NC10H6TeO2Sn-t-Bu2Cl (5), respectively, and t-Bu2SnCl2.
*Corresponding author. E-mail: beckmann@chemie.fu-berlin.de.
(1) Reviews and references cited therein: (a) Holmes, R. R. Acc.
Chem. Res. 1989, 22, 190. (b) Jain, V. K. Coord. Chem. Rev. 1994, 135-
136, 809. (c) Beckmann, J.; Jurkschat, K. Coord. Chem. Rev. 2001, 215, 267.
(d) Chandrasekhar, V.; Nagendran, S.; Baskar, V. Coord. Chem. Rev. 2002,
235, 1. (e) Chandrasekhar, V.; Gopal, K.; Thilagar, P. Acc. Chem. Res. 2007,
40, 420.
The molecularstructures of4-6 are shown in Figures 1- 3,
and selected bond parameters are collected in the captions of
the figures. The spatial arrangement of the Sn atoms is
(2) Beckmann, J.; Dakternieks, D.; Duthie, A.; Lewcenko, N. A.;
Mitchell, C. Angew. Chem., Int. Ed. 2004, 43, 6683.
(3) Beckmann, J.; Dakternieks, D.; Duthie, A.; Mitchell, C. Dalton
Trans. 2005, 1563.
(4) Beckmann, J.; Finke, P.; Hesse, M.; Wettig, B. Angew. Chem., Int.
Ed. 2008, 47, 9982.
r
2009 American Chemical Society
Published on Web 06/25/2009
pubs.acs.org/Organometallics

4226 Organometallics, Vol. 28, No. 14, 2009
Beckmann et al.
Figure 1. Molecular structure of 4 showing 30% probability
displacement ellipsoids and the atom numbering. Selected bond
˚
parameters [A, deg]: Sn1-O1 2.247(6), Sn1-O2 2.084(7), Sn1-
Cl1 2.461(3), Sn1-C50 2.17(1), Sn1-C60 2.178(1), Te1-O1
1.855(6), Te1-O2 1.886(7), Te1-C10 2.138(9), O1-Sn1-O2
72.4(3), O1-Sn1-Cl1 155.0(2), O1-Sn1-C50 97.3(4), O1-
Sn1-C60 90.4(4), O2-Sn1-Cl1 82.8(2), O2-Sn1-C50
118.6(4), O2-Sn1-C60 118.0(4), Cl1-Sn1-C50 96.4(3),
Cl1-Sn1-C60 99.6(4), C50-Sn1-C60 122.5(4), O1-Te1-O2
86.4(3), O1-Te1-C10 97.2(3), O2-Te1-C10 100.0(3), Sn1-
O1-Te1 98.1(3), Sn1-O2-Te1 103.0(3).
Figure 2. Molecular structure of 5 showing 30% probability
displacement ellipsoids and the atom numbering. Symmetry
code used to generate equivalent atoms: a = 2-x, 1-y, 1-z.
˚
Selected bond parameters [A, deg]: Sn1-O1 2.165(6), Sn1-O2
2.075(5), Sn1-C20 2.210(8), Sn1-C30 2.160(8), Sn1-Cl1
2.517(4), Te1-O1 1.900(6), Te1-O2 1.944(5), Te1 O2a
3 3 3
Scheme 1
2.650(6), Te1 N1 2.533(8), Te1-C10 2.123(8), O1-Te1-O2
3 3 3
82.8(2), O1-Te1-C10 99.6(3), O2-Te1-C10 95.8(3),
O1-Sn1-O2 73.6(2), O1-Sn1-Cl1 155.8(2), O1-Sn1-C20
99.3(3), O1-Sn1-C30 92.0(3), O2-Sn1-Cl1 82.7(2), O2-
Sn1-C20 117.1(3), O2-Sn1-C30 120.1(3),Cl1-Sn1-C30
95.9(2), Cl1-Sn1-C20 95.6(2), C20-Sn1-C30 122.6(3),
Sn1-O1-Te1 100.9(2), Sn1-O2-Te1 102.6(2).
Lewis acidity of the Te atom. Besides the primary coordina-
tion sphere, 5 reveals two symmetry-related intermolecular
˚
secondary Te O contacts (2.650(6) A), which link two
3 3 3
molecules into a centrosymmetric dimer in the crystal lattice.
Compound 6 shows two intramolecular Te O contacts
3 3 3
˚
(2.581(7) and 2.588(7) A) to the Sn-O-Sn linkage (146.9(3)°).
Compound 4 lacks any secondary interactions due to the
confined space around the Te atom. Due to servere repulsion
of the inorganic moiety with the tert-butyl groups in ortho-
positions, the Te atom is not coplanar with the phenyl ring of
the 2,4,5-tri-tert-butylphenyl substituent (largest deviation
distorted trigonal bipyramidal, and the Sn-O bond lengths
are in the expected range for single bonds. The axial Sn-Cl
bond lengths of 4 (2.461(3) A) and 5 (2.517(3) A) are
˚
˚
somewhat longer than those in t-Bu2SnCl2 (2.334(1) and
5
2.335 A). Taking into account the stereochemically active
8
˚
from the ideal plane 0.299(5) A).
˚
Compounds 4 and 6 are reasonably soluble in polar
solvents such as CHCl3 and THF, whereas 5 is only poorly
soluble in most solvents. The 125Te NMR spectrum (CDCl3)
of 2,4,6-t-Bu3C6H2TeO2Sn-t-Bu2Cl (4) shows a signal at δ=
1748.6 with unresolved Sn satellites (2J(125Te-119/117Sn) =
196 Hz), which is only slightly shifted compared to the
parent compound 2,4,6-t-Bu3C6H2TeCl3 (δ=1791.0).8 The
119Sn NMR spectrum (CDCl3) of 4 displays a signal at δ=
-128.3 with Te satellites (2J(119Sn-125Te)=196 Hz), which
agrees well with the spatial arrangement of the pentacoordi-
lone pair, the spatial arrangement of the Te atoms is distorted
tetrahedral for 4 (CO2 donor set), distorted octahedral for 5
(CO2 þ NO donor set), and distorted trigonal bipyramidal
for 6 (CO2þO donor set), respectively. The primary Te-O
˚
bond lengths of 4 (1.855(6), 1.886(7) A), 5 (1.900(6),
˚
˚
1.944(5) A), and 6 (1.857(6)-1.874(7) A) are significantly
shorter than the standard Te-O single bond of [(4-
MeOC6H4)2TeO]n (2.025(2) and 2.100(2) A), pointing to
6
˚
a bond order of approximately 1.5. The intramolecular
˚
Te N contact of 5 (2.533(8) A) is longer than that in
1
nated Sn atom and the C2O2Cl donor set. The H and 13C
3 3 3
7
8-Me2NC10H6TeCl3 (2.420(3) A), suggesting a reduced
˚
NMR spectra of 4 show that the two tert-butyl groups are
magnetically inequivalent, which is in good agreement with
the molecular structure established by X-ray crystallogra-
phy. The 125Te NMR spectrum (CDCl3) of 8-Me2N-
C10H6TeO2Sn-t-Bu2Cl (5) shows a signal at δ =1529.3
(5) Dakternieks, D.; Jurkschat, K.; Tiekink, E. R. T. Main Group
Met. Chem. 1994, 17, 471.
(6) Beckmann, J.; Dakternieks, D.; Duthie, A.; Ribot, F.;
€
Schurmann, M.; Lewcenko, N. A. Organometallics 2003, 22, 3257.
(7) Beckmann, J.; Bolsinger, J.; Duthie, A. Manuscript in prepara-
tion.
(8) Beckmann, J.; Heitz, S.; Hesse, M. Inorg. Chem. 2007, 46, 3275.

Note
Organometallics, Vol. 28, No. 14, 2009 4227
time for each spectrum 24 h). Like the 119Sn NMR signal, the
1H and 13C NMR chemical shifts of 5 were slightly broad,
which is explained by a dynamic exchange process, namely, a
monomer-dimer equilibrium in solution. This is supported
by an osmometric molecular weight determination, which
reveals a degree of association of 1.64 in CHCl3. An attempt
to measure a reasonable 125Te and 119Sn NMR spectrum of 5
at -20 °C failed due to the poor solubility. The 125Te NMR
(CDCl3) of (2,6-Mes2C6H3Te)2O5(Sn-t-Bu2)2 (6) shows a
signal at δ=1613.5 (ω1/2=42 Hz), which is shifted to higher
frequencies when compared to [2,6-Mes2C6H3Te(O)OH]2
(δ = 1403).4 The 119Sn NMR spectrum (CDCl3) of 6 shows
a signal at δ=-253.3 with Sn (2J(119Sn-117Sn)=528 Hz)
and Te satellites (2J(119Sn-125Te)=32 Hz) that are consis-
tent with the spatial arrangement of the pentacoordinated Sn
atoms and the C2O3 donor set. While the magnitude of the
2J(119Sn-117Sn) coupling agrees well with the wide Sn-O-
Sn angle,9 no explanation can be given for the small
1
2J(119Sn-125Te) coupling at this point in time. The H and
13C NMR spectra show two sets of signals for the magneti-
cally inequivalent tert-butyl groups, confirming that
the molecular structure is retained in solution. Stannatellur-
oxanes 4-6 were also characterized by ESI-TOF MS
spectrometry, a method that allows the detection of (trace
amounts of) ionic species formed by autoionization in
solution. For 4 and 5, significant mass clusters were detected
in the positive mode of the cations [(RTe)3t-Bu2SnO5]þ,
[(RTe)2t-Bu2SnO3(OH)]þ, [(RTe)t-Bu2SnO(OH)Cl]þ, and
[(RTe)t-Bu2SnO2]þ (R = 2,4,6-t-Bu3C6H2, 8-Me2NC10H6),
respectively, whereas 6 showed a mass cluster for the cation
[(RTe)2(t-Bu2Sn)2O4(OH)]þ (R=2,6-Mes2C6H3).
In an effort to investigate their ability to fix carbon
dioxide, solid and liquid samples of 4 and 6 in CDCl3 were
treated with gaseous CO2 at room temperature. No reaction
was observed by means of IR and NMR spectroscopy. Thus,
unlike [p-MeOC6H4)2TeOSn-t-Bu2O]2 (1),2,3 no evidence for
the formation of stannatelluroxane carbonates was found.
Figure 3. (a) Molecular structure of 6 showing 30% probability
displacement ellipsoids and the atom numbering scheme and
(b) inorganic core of 6. Selected bond parameters [A, deg]: Sn1-
˚
Experimental Section
O3 2.165(6), Sn1-O4 2.174(6), Sn1-O5 1.997(5), Sn1-C70 2.10
(1), Sn1-C80 2.21(1), Sn2-O1 2.162(7), Sn2-O2 2.142(7),
Sn2-O5 2.016(5), Sn2-C90 2.07(1), Sn2-C100 2.24(2), Te1-
O1 1.869(7), Te1-O4 1.857(6), Te1...O5 2.588(7), Te1-C10
General Considerations. The starting compounds (t-Bu2S-
nO)3,10 2,4,6-t-Bu3C6H2TeCl3,8 8-Me2NC10H6TeCl3,7 2,6-
Mes2C6H3TeCl3, and [2,6-Mes2C6H3Te(O)OH]2 were pre-
4
pared according to a literature procedure. The solution 1H,
13C, 119Sn, and 125Te NMR spectra were collected using a Jeol
JNM-LA 400 FT spectrometer and a Jeol Eclipse þ 500 FT
spectrometer and are referenced against Me4Si, Me4Sn, and
Me2Te. Electrospray ionization time-of-flight ESI-TOF mass
spectra were measured on an Agilent 6210 mass spectro-
meter (Agilent Technologies, Santa Clara, CA). Solvent flow
rate was adjusted to 4 μL/min. The spray voltage and skimmer
voltage were set to 4 kV and 150 V, respectively. Mole-
cular weights were determined using a Knauer vapor pressure
osmometer. Microanalyses were obtained from a Vario EL
elemental analyzer.
2.199(6), Te2-O2 1.874(7), Te2-O3 1.858(7), Te2 O5 2.581
3 3 3
(7), Te2-C40 2.169(7), O3-Sn1-O4 155.5(2), O3-Sn1-O5
79.3(2), O4-Sn1-O5 79.4(2), O3-Sn1-C70 93.1(3), O3-
Sn1-C80 98.7(4), O4-Sn1-C70 92.8(3), O4-Sn1-C80
98.2(4), O5-Sn1-C70 133.1(4), O5-Sn1-C80 104.7(5),
C70-Sn1-C80 122.1(6), O1-Sn2-O2 156.3(3), O1-Sn2-O5
79.6(2), O2-Sn2-O5 79.5(2), O1-Sn2-C90 91.6(3),O1-Sn2-
C100 99.6(3), O2-Sn2-C90 94.2(3), O2-Sn2-C100 96.7(3),
O5-Sn2-C90 132.2(4), O5-Sn2-C100 105.9(4), C90-Sn2-
C100 121.9(5), O1-Te1-O4 105.1(3), O1-Te1-C10 96.5(3),
O4-Te1-C10 98.1(3), O2-Te2-O3 105.6(3), O2-Te2-C40
98.6(3), O3-Te2-C40 97.1(3), Sn1-O5-Sn2 146.9(3), Sn1-
O4-Te1 111.8(3), Sn1-O3-Te2 111.5(3), Sn2-O1-Te1 111.4
(3), Sn2-O2-Te2 112.5(4).
Synthesis of 4-6. A solution or suspension of the appropriate
aryltellurium trichloride (240 mg of 2,4,6-t-Bu3C6H2TeCl3,
202 mg of 8-Me2NC10H6TeCl3, 273 mg of 2,6-Mes2C6H3TeCl3;
0.50 mmol) and (t-Bu2SnO)3 (246 mg, 0.33 mmol for 4
and 5; 620 mg, 0.83 mmol for 6) in THF (60 mL) was
stirred at rt for 6 h. The volume of the solution was reduced to
(ω1/2=42 Hz), which is shifted to higher frequencies com-
pared to the parent compound 8-Me2NC10H6TeCl3 (δ =
1317.1 (CDCl3)).7 The 119Sn NMR spectrum (CDCl3) of 5
exhibits a signal at δ=-149.1 (ω1/2=89 Hz), which is also
consistent with the spatial arrangement of the pentacoordi-
nated Sn atom and the C2O2Cl donor set. No satellites were
observed due to the poor signal-to-noise ratio (acquisition
(9) Lockhart, T. P.; Puff, H.; Schuh, W.; Reuter, H.; Mitchell, T. N. J.
Organomet. Chem. 1989, 366, 61.
(10) Puff, H.; Schuh, W.; Sievers, R.; Wald, W.; Zimmer, E. J.
Organomet. Chem. 1984, 260, 271.

4228 Organometallics, Vol. 28, No. 14, 2009
Table 1. Crystal Data and Structure Refinement of 4-6
Beckmann et al.
4
5 THF
6
3
formula
fw, g mol-1
cryst syst
C
673.38
monoclinic
0.31 ꢀ 0.18 ꢀ 0.07
P21/n
11.949(2)
10.2751(8)
25.423(3)
90
91.64(1)
90
3120.1(7)
4
1.433
150
1.839
1352
26H47ClO2SnTe
C24H38ClNO3SnTe
670.29
triclinic
0.25 ꢀ 0.21 ꢀ 0.08
P1
C64H86O5Sn2Te2
1427.91
monoclinic
0.50 ꢀ 0.13 ꢀ 0.05
C2/c
21.52(1)
21.417(5)
29.85(1)
90
96.22(4)
90
13676(9)
8
1.387
cryst size, mm
space group
˚
a, A
8.56(1)
˚
b, A
12.65(1)
12.90(2)
100.4(1)
92.4(1)
90.39(9)
1373(3)
2
1.622
150
2.093
664
˚
c, A
R, deg
β, deg
γ, deg
3
˚
V, A
Z
F
T, K
calcd, Mg m-3
150
1.608
5712
μ(Mo KR), mm-1
F(000)
θ range, deg
index ranges
1.86 to 25.25
-14 e h e 14
0 e k e 12
0 e l e 30
5643
2.08 to 29.20
-11 e h e 11
-17 e k e 17
-17 e l e 17
14 890
2.22 to 29.29
-29 e h e 29
-29 e k e 24
-40 e l e 40
65 721
no. of reflns collected
completeness to θmax
no. indep reflns
99.8%
5643
98.2%
7303
97.7%
18 258
no. obsd reflns with (I>2σ(I))
no. refined params
GooF (F2)
3258
275
0.866
0.0530
0.1543
<0.001
0.972/-1.600
2371
280
0.994
0.0375
0.0844
<0.001
0.602/-0.940
5397
730
0.958
0.0570
0.1149
<0.001
0.900/-0.713
R1 (F) (I > 2σ(I))
wR2 (F2) (all data)
(Δ/σ)max
-3
˚
largest diff peak/hole, e A
10 mL under vacuum. Colorless single crystals of 4, 5 THF,
and 6 were obtained within 12 h. The crystals of 5 THF were
dried for 2 h at 40 °C under vacuum to give an analytical sample
of 5.
Alternative Synthesis of 6. A solution of [2,6-Mes2C6H3Te(O)-
OH]2 (474 mg; 0.50 mmol) and (t-Bu2SnO)3 (246 mg; 0.33 mmol)
in toluene (50 mL) was heated under reflux in a Dean-Stark
apparatus for 2 h. The volume of the solution was reduced to
10 mL under vacuum. Colorless single crystals of 6, which were
obtained within 12 h, were isolated by filtration. Yield: 542 mg,
0.38 mmol, 76%.
3
3
2,4,6-t-Bu3C6H2TeO2Sn-t-Bu2Cl (4). Yield: 272 mg, 0.41 mmol;
81%. 1H NMR (CDCl3): δ 7.37 (s, 2H; Ar), 1.49 (s, 18H; CH3),
1.38 (s, 9H; CH3), 1.24 (s, 18H; CH3). 13C NMR (CDCl3): δ
156.7, 152.3, 149.8, 141.5, 125.5, 119.39 (Ar), 45.1, 42.1, 39.7,
34.7, 33.8, 31.5, 31.4, 30.4 (CMe3). 119Sn NMR (CDCl3): δ -
128.3 (2J(119Sn-125Te)=196 Hz). 125Te NMR (CDCl3): δ 1748.6
(2J(125Te-119/117Sn)=196 Hz). Anal. Calcd for C26H47ClO2SnTe
(673.41): C, 46.37; H, 7.03. Found: C, 46.25; H, 6.78. ESI-TOF
MS: m/z 1433.4 [C62H105O5Te3Sn]þ, 1044.1 [C44H77O4Te2Sn]þ,
675.1 [C26H48O2SnTeCl]þ, 639.2 [C26H47O2SnTe]þ.
X-ray Crystallography. Intensity data of 4-6 were collected
on a STOE IPDS 2T area detector with graphite-monochro-
˚
mated Mo KR (0.7107 A) radiation. The structures were solved
by direct methods and difference Fourier synthesis using
SHELXS-97 and SHELXL-97 implemented in the program
WinGX 2002.11 Full-matrix least-squares refinements were
done on F2, using all data. All non-hydrogen atoms were refined
using anisotropic displacement parameters. Hydrogen atoms
were included in geometrically calculated positions using a
riding model and were refined isotropically. Disorder of the
inorganic core of 6 was resolved with split occupancies of 0.75
(Te1, Te2, Sn1, Sn2, and O1-O5) and 0.25 (Te10, Te20, Sn10,
Sn20, and O10-O50). Crystal and refinement details are collected
in Table 1. Crystallographic data (excluding structure factors) for
the structural analyses have been deposited with the Cambridge
Crystallographic Data Centre, CCDC numbers 733996 (4),
733997 (5), and 733998 (6). Copies of this information may be
obtained free of charge from The Director, CCDC, 12 Union
Road, Cambridge CB2 1EZ, UK (fax: þ44-1223-336033; e-mail:
deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
8-Me2NC10H6TeO2Sn-t-Bu2Cl (5). Yield: 147 mg, 0.25 mmol;
1
50%. H NMR (CDCl3): δ 8.68 (d, 2H; Ar), 8.05 (d, 2H; Ar),
7.87-7.81 (m, 4H; Ar), 7.59-7.57 (m, 4H; Ar), 3.34 (s, 12 H,
NCH3), 1.03 (s, 36 H, CCH3). 13C NMR (CDCl3): δ 148.6, 140.9,
134.9, 131.9, 131.6, 131.3, 127.6, 127.4, 126.8, 119.7 (Ar), 47.9
(NMe2), 40.9 (CMe3), 29.8 (CMe3). 119Sn NMR (CDCl3): δ -
149.1 (ω1/2 = 89 Hz). 125Te NMR (CDCl3): δ 1529.3 (ω1/2
=
42 Hz). Anal. Calcd for C20H30ClNO2TeSn (598.22): C, 40.15; H,
5.05; N, 2.34. Found: C, 39.99; H, 4.84; N, 2.28. ESI-TOF MS:
m/z 1208.0 [C44H54N3O5SnTe3]þ, 895.0 [C32H43N2O4SnTe2]þ,
600.0 [C20H31NO2SnTeCl]þ, 564.0, [C20H30NO2SnTe]þ. MW:
981 g mol-1 (c 10-25 mg/g CHCl3).
(2,6-Mes2C6H3Te)2O5(Snt-Bu2)2 (6). Yield: 550 mg, 0.39 mmol,
77%. 1H NMR (CDCl3): δ 7.47 (t, 1H; Ar), 7.03 (d, 2H; Ar), 6.82
(s, 4H; Ar), 2.29 (s, 6H; CH3), 2.0 (s, 12H; CH3), 0.95 (s, 9H;
CH3), 0.88 (s, 9H; CH3). 13C NMR (CDCl3): δ 146.3, 146.1,
137.5, 136.7, 136.4, 130.9, 129.3, 128.1 (Ar), 41.5, 35.5 (CMe3),
30.2, 29.9 (CMe3), 21.4, 21.0 (ArMe). 119Sn NMR (CDCl3): δ -
253.3 (2J(119Sn-117Sn)=528 Hz, 2J(119Sn-O-125Te) = 32 Hz).
125Te NMR (CDCl3): δ 1613.5 (ω1/2 =42 Hz). Anal. Calcd for
C64H86O5Sn2Te2 (1427.98): C, 53.83; H, 6.07. Found: C, 53.86;
H, 5.91. ESI-TOF MS: m/z 1429.3 [C64H87O5Sn2Te2]þ.
Acknowledgment. TheDeutscheForschungsgemeinschaft
(DFG) is gratefully acknowledged for financial support.
Supporting Information Available: This material is available
free of charge via the Internet at http://pubs.acs.org.
(11) Farrugia, L. J. J. Appl. Crystallogr. 1999, 32, 837.