Cyclic and polycyclic tellurium-tin and tellurium-lead compounds - Synthesis, structures and thermal decomposition

Article abstract of DOI:10.1039/c2cc32615a

The miscellaneously substituted silyltellanes tBu ₂PhSiTeSiMe₃ (1) and (Me₃Si) ₃SiTeSiMe₃ were used to synthesize the cyclic tin(ii) and lead(ii) tellurolates [(tBu₂PhSiTe)₄M

Full text of DOI:10.1039/c2cc32615a

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COMMUNICATION
Cyclic and polycyclic tellurium–tin and tellurium–lead compounds – synthesis,
structures and thermal decompositionw
a
a
b
b
¨ ¨
Stephan Traut, Carsten von Hanisch,* Alexander Peter Hahnel and Sven Stahl
Received 12th April 2012, Accepted 23rd May 2012
DOI: 10.1039/c2cc32615a
The miscellaneously substituted silyltellanes tBu2PhSiTeSiMe3
(1) and (Me3Si)3SiTeSiMe3 were used to synthesize the cyclic
tin(II) and lead(II) tellurolates [(tBu2PhSiTe)4M2] (M = Sn (2),
Pb (3)), [tBu2PhSiTePbC(SiMe3)3]2 (4) and the uncommon
cluster compound [{(Me3Si)3SiTe}4Te2Sn4] (5).
tBu2PhSiTeSiMe3 (1) with the large tBu2PhSi group as a
protecting group and a Me3Si substituent as a leaving group.10
Compound 1 was obtained as a greenish oil in a yield of 91%.
The 125Te NMR spectrum shows a singlet at ꢀ998.3 ppm, and in
the 29Si{1H}-NMR spectrum, two different signals at ꢀ5.6 ppm
and at 30.9 ppm – each as a singlet – can be observed.
Based on the successful synthesis of binary bismuth–tellurium
species in the reactions of the miscellaneously substituted silyltellane
with chlorobismuthanes,11 we investigate reactions of silyltellanes 1
and (Me3Si)3SiTeSiMe312 with metal salts of Sn and Pb.
Besides the fundamental interest in the formation and stability
of chemical bonds between heavy main group elements, binary
molecular compounds of the systems M–Te (M = Sn, Pb) are
of considerable interest because of their potential use as single-
source precursors for the formation of MTe nanocrystals or
thermoelectric materials.1,2 However, molecular compounds
of these compositions are still scarce due to the high instability
of bonds between these elements. Whereas several tellurium
compounds of tin(IV) and lead(IV) such as (R2SnTe)n (R = Me,
Ph, n = 3; R = tBu, Fe(CO)2Cp, Mo(CO)3Cp, n = 2) and
4-CH3C6H4COTeMPh3 (M = Sn, Pb) are known,3 tellurium
compounds of tin(II) and lead(II) are rarely described.4–8 Examples
are the cyclic compounds [M{TeSi(SiMe3)3}2]2 or the ditellurido
imidodiphosphinate complexes [M{(TePiPr2)2N}2] (M = Sn,
Pb).1a,5 Furthermore, the chemistry of the anions [PbTe3]4ꢀ and
[M2Te3]2ꢀ (M = Sn, Pb) has been the focus of research for several
years.6 Moreover, the 1D-phenyltellurolato complex [Sn(TePh)2] is
worth mentioning.7 Recently, mixed valence organo tin tellurides
were described. These compounds were obtained from the
reaction of the tin(I) species (RSn)2 (R = pincer-type ligand)
with elementary tellurium.8
The reaction of 1 with SnCl2 in Et2O at ꢀ74 1C leads to a
yellow solution. From this solution, [(tBu2PhSiTe)4Sn2] (2) can
be obtained as yellow crystals in a good yield. Compound 2
crystallizes in the monoclinic spacegroup P21/c with four
molecules in the unit cell (Fig. 1). The molecular structure can
be described as a dimer of two (tBu2PhSiTe)2Sn fragments
under formation of a folded four-membered ring with an angle
of torsion along the Te(1)–Te(2) axis of 137.71. The substituents
around the ring show an all-trans arrangement. The Sn–Te
bond lengths in the Sn2Te2 core are between 293.9(2) pm
and 299.0(2) pm and in the same range as the endocyclic bonds
Here, we report on our research on molecular compounds of
the system M–Te (M = Sn, Pb) and describe the synthesis and
crystal structure of the dimeric complexes [(tBu2PhSiTe)4M2]
(M = Sn (2), Pb (3)), [tBu2PhSiTePbC(SiMe3)3]2 (4) and the
uncommon cluster compound [{(Me3Si)3SiTe}4Te2Sn4] (5).
Organosilicon substituents with a high steric demand are good
protecting groups in main group chemistry.9 For this reason,
we synthesized the miscellaneously substituted silyltellane
Fig. 1 Molecular structure of 2; thermal ellipsoids represent a 50%
probability level, hydrogen atoms are not shown, selected bond lengths
(pm) and angles (1): Sn(1)–Te(1) 299.0(2), Sn(1)–Te(2) 293.9(2), Sn(2)–Te(1)
295.6(2), Sn(2)–Te(2) 297.5(2), Sn(1)–Te(4) 281.8(2), Sn(2)–Te(3) 283.3(2),
Te(1)–Si(1) 254.5(6), Te(2)–Si(2) 254.3(7), Te(3)–Si(3) 251.3(5), Te(4)–Si(4)
252.5(5); Sn(1)–Te(1)–Sn(2) 81.67(6), Sn(1)–Te(2)–Sn(2) 90.26(6),
Te(1)–Sn(1)–Te(2) 81.48(5), Te(1)–Sn(2)–Te(2) 81.46(6), Te(1)–Sn(1)–Te(4)
93.46(7), Te(1)–Sn(2)–Te(3) 87.90(6), Te(2)–Sn(1)–Te(4) 89.06(6),
Sn(2)–Te(3) 90.53(6), Sn(2)–Te(3)–Si(3) 102.21(16), Sn(1)–Te(4)–Si(4)
104.38(15), Sn(1)–Te(1)–Te(2)–Sn(2) 137.71(8).
a Fachbereich Chemie and Wissenschaftliches Zentrum fur
¨
Materialwissenschaften, Philipps Universitat Marburg,
¨
Hans-Meerwein-Straße, D-35032 Marburg, Germany.
E-mail: haenisch@chemie.uni-marburg.de
b Institut fur Nanotechnologie, KIT, Campus Nord, Postfach 3640,
D-76021, Karlsruhe, Germany
¨
w Electronic supplementary information (ESI) available: Experimental
details. CCDC 876450 (2), 876451 (3), 876452 (4) and 876453 (5). For
crystallographic data, see also ref. 17. For ESI and crystallographic
data in CIF or other electronic format see DOI: 10.1039/c2cc32615a
c
6984 Chem. Commun., 2012, 48, 6984–6986
This journal is The Royal Society of Chemistry 2012

in [{(Me3Si)3SiTe}2Sn]2 (294.6 pm–295.6 pm).5 In contrast, the
exocyclic Sn–Te bonds are shortened due to the lower coordina-
tion number of these Te atoms (281.8(2) pm and 283.3(2) pm).
Room-temperature NMR experiments do not show the
expected signals for the cyclic and the exocyclic silyltellurolato
ligand. Instead, the 1H NMR spectrum shows one peak for
the tert-butyl groups and just one set of phenyl signals. The
125Te NMR spectrum displays only one singlet at ꢀ715.0 ppm.
The 29Si{1H} NMR spectrum shows one singlet at 34.7 ppm.
Low-temperature 1H NMR experiments exhibit coalescence at
ꢀ3 1C and suggest a displacement of the tBu2PhSi groups in
solution. A complete splitting of the tBu group signals with a
value of 76 Hz can be achieved at ꢀ70 1C and leads to an
energy barrier DGz = 54.3 kJ molꢀ1
.
We also succeeded in synthesizing a lead–tellurium compound,
by the reaction of 1 with PbCl2 in Et2O at ꢀ74 1C. Orange
crystals of the cyclic species [(tBu2PhSiTe)4Pb2] (3) form during a
period of two days. Compound 3 crystallizes in the monoclinic
space group C2/c with four molecules in the unit cell (Fig. 2). The
molecular structure is almost identical to that of tin compound 2.
The angle of torsion is 138.41 and in the same range as in the tin
compound. The Pb–Te bond lengths in the Pb2Te2 core are
between 300.0(1) pm and 303.8(1) pm, whereas the exocyclic
bonds with 289.2(1) pm are somewhat shorter. Therefore, the
measured Pb–Te bond lengths are in the same range as in the
[Pb2Te3]2ꢀ anion (295.9 pm–301.5 pm),6e but considerably longer
than the sum of the calculated covalent radii (280 pm).13
NMR analysis of 3 shows signals which indicate the existence
of only one tBu2PhSiTe group. Low-temperature NMR experi-
ments do not display the expected coalescence, instead signals
that suggest a monomer–dimer equilibrium. This may be a
consequence of the less stable Pb–Te bonds in comparison to
the Sn–Te bond of compound 2.14
Fig. 3 Molecular structure of 4; thermal ellipsoids represent a 50%
probability level, hydrogen atoms are not shown, selected bond lengths
(pm) and angles (1): Pb(1)–Te(1) 310.4(1), Pb(1)–Te(2) 313.2(1),
Pb(2)–Te(1) 313.7(1), Pb(2)–Te(2) 306.9(1), Te(1)–Si(1) 257.3(4),
Te(2)–Si(2) 257.9(3), Pb–C 241.4(11)–244.7(13); Te(1)–Pb(1)–Te(2)
83.60(3), Te(1)–Pb(2)–Te(2) 84.09(3), Pb(1)–Te(1)–Pb(2) 92.06(3),
Pb(1)–Te(2)–Pb(2) 92.84(3); Pb(1)–Te(1)–Te(2)–Pb(2) 152.1(3).
molecular structure consists of a Pb2Te2 core folded slightly in a
butterfly manner with an angle of torsion of 152.11 along the
Te(1)–Te(2) axis. The organosilicon ligands at the Pb and Te atoms
are all trans-aligned. The Pb–Te bond distances are between
306.9(1) pm and 313.2(1) pm and hence considerably longer
than the lengths of core Pb–Te bond in 3. This may be a result
of the steric demand of the organosilicon ligands at the lead
and the tellurium atoms.
12
Starting from (Me3Si)3SiTeSiMe3 and SnCl2 at a molar
ratio of 1 : 1, we obtained the unique cluster [{(Me3Si)3SiTe}4-
Te2Sn4] (5), which can be isolated as dark red crystals upon cooling
the reaction mixture to ꢀ35 1C (Fig. 4). Compound 5 crystallizes in
the monoclinic space group P21/n with two molecules in the unit
cell and consists of a Te6Sn4-framework with four peripheral
(Me3Si)3Si groups. The structure can be described as a planar
Sn2Te2 ring with two exocyclic {(Me3Si)3SiTe}2Sn fragments,
which are trans-aligned to each other. Surprisingly, the molecules
contain two Te2ꢀ ions beside four (Me3Si)3SiTeꢀ ligands. This
shows that the (Me3Si)3Si substituent can act as a leaving
group under these conditions.
[tBu2PhSiTePbC(SiMe3)3]2 (4) was obtained from the reac-
tion of 1 with the tris(trimethylsilyl)methylchloridoplumbylene
(Me3Si)3CPbCl in Et2O (Fig. 3).15 It crystallizes as red blocks
upon cooling the reaction mixture to ꢀ35 1C. The structure
solution and refinement were carried out in the monoclinic
space group P21/n with four molecules in the unit cell. The
Within the central Te2Sn2 ring the Sn(2)–Te(3)–Sn(2)0 bond
angle amounts to 89.29(1)1, the Te(3)–Sn(2)–Te(3)0 bond angle
to 90.71(1)1. The Te–Sn bonds within the Te2Sn2 ring are
290.3(1) and 292.6(1) pm long and therefore shorter than in
compound 2. The exocyclic Sn–Te bonds around Sn(1) show values
of 286.2(2) pm (Sn(1)–Te(1)), 288.6(1) pm (Sn(1)–Te(2)) and
296.1(1) pm (Sn(1)–Te(3)). Besides these covalent bonds, secondary
interactions between Te(1) and Sn(2) (330.4(8) pm) as well as Te(2)
and Sn(2)0 (313.6(8) pm) can be observed which are between
covalent bonds and van der Waals interactions (423.0 pm).13,16
Furthermore, the Te6Sn4 core of compound 5 displays a
fragment of the cubic SnTe. Therefore, this compound represents
an intermediate stage of the formation of the binary SnTe phase
from the molecular precursor [Sn{TeSi(SiMe3)3}2]2 as described
by Seligson and Arnold.5
Fig. 2 Molecular structure of 3; thermal ellipsoids represent a 50%
probability level, hydrogen atoms are not shown, selected bond lengths
(pm) and angles (1): Pb(1)–Te(1) 303.8(1), Pb(1)–Te(1)0 300.0(1), Pb(1)–Te(2)
289.2(1), Te(1)–Si(1) 254.7(1), Te(2)–Si(2) 251.6(2); Te(1)–Pb(1)–Te(1)0
81.65(3), Te(1)–Pb(1)–Te(2) 91.34(2), Te(1)0–Pb(1)–Te(2) 88.29(1), Pb(1)–
Te(1)–Pb(1)0 90.03(3), Si(1)–Te(1)–Pb(1) 110.68(3), Si(1)–Te(1)–Pb(1)0
104.63(4), Si(2)–Te(2)–Pb(1) 102.34(4); Pb(1)–Te(1)–Te(1)0–Pb(2) 138.36(3).
Thermogravimetric analysis under helium gas flow was carried
out for compounds 2–5. Compound 2 decomposes in the
c
This journal is The Royal Society of Chemistry 2012
Chem. Commun., 2012, 48, 6984–6986 6985

J. Am. Chem. Soc., 2004, 126, 11798–11799; (e) P. Boudjouk,
M. P. Remington, D. G. Grier, W. Triebold and B. R. Jarabek,
Organometallics, 1999, 18, 4534–4537.
2 (a) C. Erk, A. Berger, J. Wendorff and S. Schlecht, Dalton Trans.,
2010, 39, 11248–11254; (b) K. Fang Hsu, S. Loo, F. Guo, W. Chen,
J. S. Dyck, C. Uher, T. Hogan, E. P. Polychroniadis and
M. Kanatzidis, Science, 2004, 303, 818–821; (c) S. Schlecht,
M. Budde and L. Kienle, Inorg. Chem., 2002, 41, 6001–6005;
(d) G. Barone, T. G. Hibbert, M. F. Mahon, K. C. Molloy,
L. S. Price, I. P. Parkin, A. M. E. Hardy and M. N. Field,
J. Mater. Chem., 2001, 2, 464–468; (e) Y. Cheng, T. J. Emge and
J. G. Brennan, Inorg. Chem., 1996, 35, 342–346; (f) CRC Handbook
of Thermoelectrics, ed. D. M. Rowe, CRC Press, New York, 1995;
(g) D. H. R. Barton and H. Dadoun, New J. Chem., 1982, 6, 53–57.
3 (a) K. Tani, R. Yamada, T. Kanda, M. Suzuki, S. Kato and T. Murai,
Organometallics, 2002, 21, 1487–1492; (b) U. Herzog and G. Rheinwald,
J. Organomet. Chem., 2001, 627, 23–36; (c) K. Merzweiler and H. Kraus,
Z. Naturforsch., B, 1994, 49, 621–626; (d) I. G. Dance, Polyhedron, 1986,
5, 1037–1104; (e) B. Mathiasch, J. Organomet. Chem., 1980, 194, 37–43;
(f) A. Blecher and M. Drager, Angew. Chem., 1979, 91, 740 (Angew.
¨
Chem., Int. Ed. Engl., 1979, 18, 677); (g) H. Puff, R. Gattermayer,
R. Hundt and R. Zimmer, Angew. Chem., 1977, 89, 556–557 (Angew.
Chem., Int. Ed. Engl., 1977, 16, 547–548); (h) H. Schumann, K.-F. Thom
and M. Schmidt, J. Organomet. Chem., 1964, 2, 361–366.
4 (a) H. Schumann, Z. Anorg. Allg. Chem., 1967, 354, 192–200;
(b) B. Menzebach and P. Bleckmann, J. Organomet. Chem., 1975,
91, 291–294; (c) H.-J. Jacobsen and B. Krebs, J. Organomet. Chem.,
Fig. 4 Molecular structure of 5; thermal ellipsoids represent a 50%
probability level, hydrogen atoms are not shown, selected bond lengths
(pm) and angles (1): Sn(1)–Te(1) 286.2(2), Sn(1)–Te(2) 288.6(1), Sn(1)–Te(3)
296.1(1), Sn(2)–Te(3) 290.3(1), Sn(2)–Te(3)0 292.6(1), Te(2)–Sn(2)0 313.6(8),
Te(1)–Sn(2) 330.4(8), Te(1)–Si(1) 253.5(2), Te(2)–Si(5) 235.9(2);
Te(1)–Sn(1)–Te(2) 83.72(2), Te(1)–Sn(1)–Te(3) 96.52(3), Te(2)–Sn(1)–Te(3)
94.96(2), Sn(1)–Te(3)–Sn(2) 90.10(3), Sn(1)–Te(3)–Sn(2)0 87.62(2), Te(3)–
Sn(2)–Te(3)0 90.71(2), Sn(2)–Te(3)0–Sn(2)0 89.29(1).
1977, 136, 333–338; (d) M. Drager, A. Blecher, H.-J. Jacobsen and
¨
B. Krebs, J. Organomet. Chem., 1978, 161, 319–325; (e) H. Puff,
G. Bertram, B. Ebeling, M. Franken, R. Gattermayer, R. Hundt,
W. Schuh and R. Zimmer, J. Organomet. Chem., 1989, 379, 235–245.
5 A. L. Seligson and J. Arnold, J. Am. Chem. Soc., 1993, 115, 8214–8220.
6 (a) C. D. W. Jones, F. J. DiSalvo and R. C. Haushalter, Inorg. Chem.,
1998, 37, 821–823; (b) H. Borrmann, J. Campbell, D. Dixon,
H. Mercier, A. Pirani and G. J. Schrobilgen, Inorg. Chem., 1998, 37,
6656–6674; (c) C.-W. Park, R. Salm and J. Ibers, Can. J. Chem., 1995,
temperature range of 210–290 1C with an overall mass loss of
66.7% (calculated for the formation of SnTe: 69.7%). A different
behaviour was observed for compound 3, which shows a first
decomposition step between 50 and 751C with a mass loss of
11.9%. This corresponds to the elimination of one tBu2PhSi
group (calc. 12.2%). Further decomposition occurs in the
temperature range of 190 to 250 1C with a mass loss of 51.93%
and indicates the formation of PbTe. Compound 4 shows a
gradual mass loss in the temperature range of 100 to 300 1C with
a shoulder at 190 1C. The overall mass loss is 55.1%, which fits
roughly to the formation of PbTe (calc. 57.4%). Finally, the
thermal decomposition of cluster compound 5 was investigated.
However, in all experiments under helium gas flow as well as
under vacuum, 5 shows a mass loss much larger than expected for
the formation of SnTe: calc. 55.8%, observed under helium gas
flow 61.8% and 71.2% under vacuum.
73, 1148–1156; (d) M. Bjorgvinsson, H. P. A. Mercier, K. M. Mitchell,
¨
G. J. Schrobilgen and G. Strobe, Inorg. Chem., 1993, 32, 6046–6055;
(e) M. Bjorgvinsson, J. F. Sawyer and G. Schrobilgen, Inorg. Chem.,
¨
G. J. Schrobilgen, Inorg. Chem., 1987, 26, 741–749.
¨
1991, 30, 2231–2233; (f) M. Bjorgvinsson, J. F. Sawyer and
7 A. Eichhofer, J.-J. Jiang, H. Sommer, F. Weigand, O. Fuhr,
¨
D. Fenske, C.-Y. Su and G. Buth, Eur. J. Inorg. Chem., 2010, 410–418.
´ ´
8 M. Bouska, L. Dostal, Z. Padekova, A. Lycka, S. Herres-Pawlis,
K. Jurkschat and R. Jambor, Angew. Chem., 2012, 124, 3535–3540
(Angew. Chem., Int. Ed., 2012, 51, 3478–3482).
9 (a) C. Eaborn and J. D. Smith, Coord. Chem. Rev., 1996, 154, 125–149;
(b) C. Eaborn and J. D. Smith, Dalton Trans., 2001, 1541–1552;
(c) Organic Functional Group Transformations, ed. A. R. Katritzky
and R. J. K. Taylor, Elsevier, Pergamon, Amsterdam, 1995, vol. 6,
pp. 377–406; (d) Organic Functional Group Transformations II, ed.
A. R. Katritzky and R. J. K. Taylor, Elsevier Pergamon, Amsterdam,
2005, vol. 6, pp. 381–408.
Organosilicon tellanes are possible precursors to obtain
telluro-bridged compounds of tin and lead. The uncommon
multinuclear complex 5 can be described as part of the cubic SnTe
and gives insight into the formation of solid states from molecular
precursors. Apart from the Sn–Te system with compounds 3 and 4,
we succeeded in synthesizing and structurally characterizing two
stable compounds containing lead–tellurium bonds. Moreover,
such compounds are promising single source precursors for
SnTe and PbTe as thermoelectric materials.
10 T. Kuckmann, M. Hermsen, M. Bolte, M. Wagner and H.-W. Lerner,
¨
Inorg. Chem., 2005, 44, 3449–3458.
11 S. Traut, A. P. Hahnel and C. v. Hanisch, Dalton Trans., 2011, 40,
1365–1371.
¨
¨
12 P. Bonasia, D. Gindelbert, B. Dabbousi and J. Arnold, J. Am.
Chem. Soc., 1992, 114, 5209–5214.
13 P. Pyykko and M. Atsumi, Chem.–Eur. J., 2009, 15, 186–197.
¨
14 The H NMR spectrum of compound 3 shows at room temperature
1
one signal of the tBu groups at 1.26 ppm. At a temperature of ꢀ50 1C
two additional signals appear at 1.11 and 1.34 ppm. These signals
increase in intensity when the sample is cooled to lower temperatures,
while the signal at 1.26 ppm decreases.
The authors thank Dr Klaus Harms (Philipps Universitat
¨
Marburg) for the help concerning the X-ray structure analysis.
15 C. Eaborn, P. B. Hitchcock, J. D. Smith and S. E. So
Organometallics, 1997, 16, 5653–5658.
¨
zerli,
Notes and references
16 (a) A. Bondi, J. Phys. Chem., 1964, 68(3), 441–451; (b) M. Mantina,
A. Chamberlin, R. Valero, C. Cramer and D. Truhlar, J. Phys.
Chem. A, 2009, 113, 5806–5812.
17 STOE-IPDS 2 (Mo-Ka radiation, l = 0.71073 A). The structure
was resolved by direct methods and refined against F2 by the full-
matrix least-squares technique (Pb, Te, Sn, Si, and C were refined
anisotropically, H atoms were calculated at ideal positions).
1 (a) J. S. Ritch, T. Chivers, K. Ahmad, M. Afzaal and P. O’Brien,
Inorg. Chem., 2010, 49, 1198–1205; (b) T. Mokari, M. Thang and
P. Yang, J. Am. Chem. Soc., 2007, 129, 9864–9865; (c) J. Murphy,
M. C. Beard, A. G. Norman, S. P. Ahrenkiel, J. C- Johnson, P. Yu,
´ ´
O. I. Micic, R. J. Ellingon and A. J. Nozik, J. Am. Chem. Soc.,
2006, 128, 3241–3247; (d) W. Lu, J. Fang, K. L. Stokes and J. Lin,
c
6986 Chem. Commun., 2012, 48, 6984–6986
This journal is The Royal Society of Chemistry 2012