Chalcogen-rich lanthanide clusters: Compounds with Te2-, (TeTe)2-, TePh, TeTePh, (TeTeTe(Ph)TeTe)5-, and [(TeTe)4TePh]9- ligands; single source precursors to solid-state lanthanide tellurides

Article abstract of DOI:10.1021/ic010981w

Lanthanide metals react with PhTeTePh and elemental Te in pyridine to give (py)_yLn₄(Te)(TeTe)₂(TeTeTe(Ph)-TeTe)(Te _xTePh) (Ln = Sm (y = 9; x = 0); Tb, Ho (y = 8, x = 0.1)), and (py)₇Tm₄(Te)[(TeTe)₄TePh](Te_0.6 TePh) clusters. The Sm, Tb, and Ho compounds contain a square array of Ln(III) ions all connected to a central Te^2- ligand. Two adjacent edges of the square are bridged by ditelluride ligands, with the Ln ion that is η² bound to both of these TeTe ligands also coordinating to a terminal TePh ligand. The other two edges of the square are spanned by ditellurides that both coordinate a TePh ligand that has been displaced from the Ln ion by pyridine, to give the pentaanion (μ-η²-η²-Te₂Te(Ph)Te₂ ).^5- In the Tm compound, the displaced TePh interacts with all four TeTe units. The compounds are air-, light-, and temperature-sensitive. Upon thermolysis, they decompose to give solid-state TbTe_2-x, HoTe, or TmTe, with elimination of Te and TePh₂.

Full text of DOI:10.1021/ic010981w

Inorg. Chem. 2002, 41, 492−500
Chalcogen-Rich Lanthanide Clusters: Compounds with Te2-, (TeTe)2-,
TePh, TeTePh, (TeTeTe(Ph)TeTe)5-, and [(TeTe)4TePh]9- Ligands; Single
Source Precursors to Solid-State Lanthanide Tellurides
Deborah Freedman, Thomas J. Emge, and John G. Brennan*
Department of Chemistry, Rutgers, the State UniVersity of New Jersey, 610 Taylor Road,
Piscataway, New Jersey 08854-8087
Received September 19, 2001
Lanthanide metals react with PhTeTePh and elemental Te in pyridine to give (py)yLn4(Te)(TeTe)2(TeTeTe(Ph)-
TeTe)(Te TePh) (Ln ) Sm (y ) 9; x ) 0); Tb, Ho (y ) 8, x ) 0.1)), and (py)7Tm (Te)[(TeTe)4TePh](Te0.6TePh)
x
4
clusters. The Sm, Tb, and Ho compounds contain a square array of Ln(III) ions all connected to a central Te2-
ligand. Two adjacent edges of the square are bridged by ditelluride ligands, with the Ln ion that is η2 bound to both
of these TeTe ligands also coordinating to a terminal TePh ligand. The other two edges of the square are spanned
by ditellurides that both coordinate a TePh ligand that has been displaced from the Ln ion by pyridine, to give the
pentaanion (µ-η2-η2-Te2Te(Ph)Te2).5- In the Tm compound, the displaced TePh interacts with all four TeTe units.
The compounds are air-, light-, and temperature-sensitive. Upon thermolysis, they decompose to give solid-state
TbTe2-x, HoTe, or TmTe, with elimination of Te and TePh2.
Introduction
energy surfaces, and the combination of ionic Ln metal and
covalent Te ligands yields compounds that are particularly
difficult to isolate and characterize. This is reflected in the
literature, where over a hundred examples of structurally
characterized compounds containing Ln-S bonds, more than
35 examples of compounds with Ln-Se bonds, and only 12
Inorganic compounds of tellurium are challenging syn-
thetic targets, because bonds to this element are considerably
weaker than bonds to the lighter chalcogens sulfur or se-
lenium, and thus, compounds are relatively unstable. Because
this relative instability often leads to the formation of ma-
terials with highly unusual or useful physical properties (i.e.,
CdHgTe semiconductors,1 Bi2Te3 thermoelectric materials2),
the chemistry of metal tellurium compounds continues to
attract attention. From a fundamental perspective, compounds
with Te are interesting because they often adopt unconven-
tional molecular or solid-state structures with a wide range
of Te-Te bonds, a chemistry that parallels that of the com-
plex polyiodide compounds. Stabilities are defined by shal-
low potential energy surfaces, and structures are often un-
predictable.
analogous Ln-Te compounds have been described.3
A
majority of the 12 Ln-Te compounds contain relatively
electronegative, sterically demanding ancillary ligands4-7
(i.e., C5Me5 or Cp*) that kinetically passivate the Ln-Te
bond. Most of the remaining examples are divalent Ln(ER)2
coordination complexes of the redox active Sm, Eu, or
Yb.8-10 The tendency of the trivalent redox active metals to
reductively eliminate RTeTeR clearly reflects the inability
of Te ligands to stabilize Ln(III) oxidation states. In the
absence of stabilizing ancillary anions, the only reported
example of an isolable Ln(III)-Te compound is (Me2PCH2-
Lanthanide (Ln) ions, with their valence 4f obitals ef-
fectively shielded by filled 5s2 and 5p6 orbitals, also tend to
adopt molecular structures defined by shallow potential
(3) Nief, F. Coord. Chem. ReV. 1998, 178, 13.
(4) Berg, D.; Andersen, R. A.; Zalkin, A. Organometallics, 1988, 7, 1858.
(5) Evans, W. J.; Rabe, G. W.; Ziller, J. W.; Doedens, R. J. Inorg. Chem.
1994, 33, 2719.
* Author to whom correspondence should be addressed. E-mail: bren@
rutchem.rutgers.edu.
(1) Andresen, B. F.; Scholl, M. S., Eds. Infrared Technology and
Applications XXIV; SPIE Proceedings Vol. 3436, San Diego, CA,
1998.
(6) Zalkin, A.; Berg, D. Acta Crystallogr. 1988, C44, 1488.
(7) Recknagel, A.; Noltemeyer, M.; Stalke, D.; Pieper, U.; Schmidt, H.
G.; Edelmann, F. T. J. Organomet. Chem. 1991, 411, 347.
(8) Khasnis, D. V.; Lee, J.; Brewer, M.; Emge, T. J.; Brennan, J. G. J.
Am. Chem. Soc. 1994, 116, 7129.
(2) Mathiprakasam, B.; Heenan, P., Eds., Proceedings of the Thirteenth
International Conference on Thermoelectrics; AIP Conference Pro-
ceedings 316, Midwest Research Institute, 1995.
(9) Brewer, M.; Khasnis, D.; Buretea, M.; Berardini, M.; Emge, T. J.;
Brennan, J. G. Inorg. Chem. 1994, 33, 2743.
(10) Cary, D. R.; Arnold, J. Inorg. Chem. 1994, 33, 1791.
492 Inorganic Chemistry, Vol. 41, No. 3, 2002
10.1021/ic010981w CCC: $22.00 © 2002 American Chemical Society
Published on Web 01/11/2002

Chalcogen-Rich Lanthanide Clusters
CH2PMe2)2La(TeSi(SiMe3)3)3.11,12 Without this chelating
phosphine ligand, the analogous Ce derivative, “Ce(TeSi-
(SiMe3)3”, decomposes below room temperature to give the
equally unstable tellurido cluster Ce5Te3(TeSi(SiMe3)3)9.11,12
While the past three years has experienced a burst of
activity describing the synthesis and characterization of stable
lanthanide clusters coordinated to chalcogenido (E2-, E )
S, Se)13-18 ligands, extension of this work to compounds of
Te has not yet appeared. The recent high-yield synthesis of
chalcogen-rich Ln compounds with (EE)2- ligands,19,20 rather
than E2- ligands, from the reactions of lanthanide chalco-
genolates with elemental E, leads to the suggestion that
(EE)2- may stabilize Ln ions more effectively than E2-, pos-
sibly to the extent that compounds with Te can be isolated
routinely. This paper outlines initial investigations into the
synthesis, characterization, stability, and thermolysis of Te-
rich Ln clusters.
tometer with Cu KR radiation. GCMS data were collected on a
5890 Series II gas chromatograph with an HP 5971 mass selective
detector.
Synthesis of (py)9Sm4(µ4-Te)(µ2-TeTe)2(µ2-TeTeTe(Ph)TeTe)-
(TePh)·5py (1). Samarium metal (0.30 g, 2.0 mmol) and Hg (0.05
g, 0.25 mmol) were added to a solution of diphenyl ditelluride (0.82
g, 2.0 mmol) in pyridine (50 mL). The reaction flask was wrapped
in aluminum foil up to the stopper. The next day elemental tellurium
was added (0.38 g, 3.0 mmol) to the yellow solution and unreacted
Sm. The following day the solution was dark red, and a brick red
solid had precipitated. The solution was filtered and layered with
20 mL of hexanes to give dark red needles (100 mgs, 10%) that
could be separated by hand from the dark solid major product.
Synthesis of (py)8Tb4(µ4-Te)(µ2-TeTe)2(µ2-TeTeTe(Ph)TeTe)-
(Te0.1TePh)·4.5py (2). Terbium metal (0.32 g, 2.0 mmol) and Hg
(0.05 g, 0.25 mmol) were added to a solution of diphenyl ditelluride
(0.82 g, 2.0 mmol) in pyridine (50 mL). The flask was wrapped in
aluminum foil. After stirring for 1 day, elemental tellurium (0.38
g, 3.0 mmol) was added to the dark golden brown mixture that
still contained unreacted Tb. Two days later the metal had been
consumed and there was a significant amount of dark red precipitate.
The flask was heated to between 60 and 75 °C for ca. 1 h to dissolve
the red solid. The red solution was filtered into a flask with either
a flat bottom (modified Erlenmeyer) or a large round-bottom and
concentrated by ca. 3 mL. Hexanes (ca. 8 mL) were added rapidly
into the solution that was then re-covered with aluminum foil and
allowed to stand at rt for 2 days to give deep red crystals (0.34 g,
35%) that were washed with hexane (5 mL) and did not decompose
or melt below 300 °C. Anal. Calcd for C64.5H62.5N10.5Tb4Te11.1: C,
25.5; H, 2.07; N, 4.84. Found: C, 25.3; H, 2.19; N, 4.33. IR: 3077
(m), 2933 (s), 2856 (s), 1630 (w), 1597 (s), 1580 (s), 1481 (m),
1465 (s), 1437 (s), 1384 (s), 1218 (m), 1145 (w), 1068 (m), 1038
(m), 1030 (m), 1004 (m), 991 (m), 825 (w), 745 (s), 732 (w), 702
(s), 623 (w), 602 (m), 451 (w), 405 (w) cm-1. Magnetic susceptibil-
ity: µeff (5-250 K) ) 7.87 (500 G); 7.91 (10 kG). The compound
does not show an absorption maximum from 350 to 800 nm in
THF. No 1H NMR resonances were detected in either THF or
pyridine. Thermolysis: 100 mg of 1 was placed in a quartz tube
under vacuum for 5 min. The tube was then sealed and the sample
temperature was increased at the rate of 20 °C/min with one end
of the tube submerged in liquid nitrogen. The temperature was held
at 550 °C for 5 h and then the tube was removed and allowed to
cool rapidly to give ca. 25 mg of nonvolatile solid. Powder
diffraction X-ray analysis revealed only TbTe2-x (0 < x < 0.3).22
Experimental Section
General Methods. All syntheses were carried out under ultrapure
nitrogen (JWS), using conventional drybox or Schlenk techniques.
Solvents (Fisher) were refluxed continuously over molten alkali
metals or K/benzophenone and collected immediately prior to use.
Anhydrous pyridine (Aldrich) was purchased and refluxed over
KOH. PhTeTePh was prepared according to literature procedures.21
Ln and Hg were purchased from Strem. Melting points were taken
in sealed capillaries and are uncorrected. IR spectra were recorded
on a Mattus Cygnus 100 FTIR spectrometer from 4000 to 600 cm-1
as Nujol mulls on NaCl plates. Electronic spectra were recorded
on a Varian DMS 100S spectrometer with the samples in a 0.10
mm quartz cell attached to a Teflon stopcock. Elemental analyses
were performed by Quantitative Technologies, Inc. (Whitehouse
NJ). These compounds are sensitive to the thermal dissociation of
neutral donor ligands at room temperature, so the experimentally
determined elemental analyses are often found to be lower than
the computed analyses. The reported values were closest to the
calculated values, but analytical determinations gave a range of
values that were usually consistent with the one of the three unit
cell formulations described below. Magnetic susceptibility was
measured on a SQUID magnetometer in a 1 T field. NMR spectra
were obtained on either Varian 300 or 400 MHz NMR spectrom-
eters, and chemical shifts are reported in δ (ppm). XR powder
diffraction profiles were obtained on a SCINTAG PAD V diffrac-
Synthesis of (py)8Ho4(µ4-Te)(µ2-TeTe)2(µ2-TeTeTe(Ph)TeTe)-
(Te0.1TePh)·4.5py (3): Method 1. Holmium metal (0.33 g, 2.0
mmol), Hg (0.05 g, 0.25 mmol), and diphenyl ditelluride (0.79 g,
1.93 mmol) were added to pyridine (50 mL), the reaction flask
was wrapped in aluminum foil, and the mixture stirred. The next
day elemental tellurium (0.38 g, 3.0 mmol) was added to the yellow
solution and unreacted Ho. The following day the solution was dark
red, and a brick red solid had precipitated. The solution was filtered
into a Schlenk flask with an outer diameter of 41 mm, concentrated
to 45 mL, layered with hexanes (20 mL), and then placed in the
dark to give dark red needles (100 mgs, 10%) that did not melt up
to 310 °C but slowly turned black and began eliminating a gas at
ca. 230 °C. Anal. Calcd for C64.5H62.5N10.5Ho4Te11: C, 25.4; H,
2.07; N, 4.83. Found: C, 24.8; H, 2.06; N, 4.73. IR: 2865 (s),
2361 (w), 1596 (m), 1579 (s), 1463 (s), 1377 (s), 1216 (m), 1144
(m), 1067 (m), 1030 (m), 990 (m), 744 (m), 727 (m), 701 (s), 622
(11) Cary, D. R.; Ball, G. E.; Arnold, J. J. Am. Chem. Soc. 1995, 117,
3492.
(12) Cary, D. R.; Arnold, J. J. Am. Chem. Soc. 1993, 115, 2520.
(13) Freedman, D.; Emge, T. J.; Brennan, J. G. J. Am. Chem. Soc. 1997,
119, 11112.
(14) Melman, J. H.; Emge, T. J.; Brennan, J. G. Chem. Commun. 1997,
2269.
(15) Freedman, D.; Melman, J. H.; Emge, T. J.; Brennan, J. G. Inorg. Chem.
1998, 37, 4162.
(16) Melman, J. H.; Emge, T. J.; Brennan, J. G. Inorg. Chem. 1999, 38,
2117.
(17) Freedman, D.; Emge, T. J.; Brennan, J. G. Inorg. Chem. 1999, 38,
4400.
(18) Freedman, D.; Sayan, S.; Emge, T. J.; Croft, M.; Brennan, J. G. J.
Am. Chem. Soc. 1999, 121, 11713.
(19) Melman, J. H.; Fitzgerald, M.; Freedman, D.; Emge, T. J.; Brennan,
J. G. J. Am. Chem. Soc. 1999, 121, 10247.
(20) (a) Kornienko, A.; Emge, T.; Brennan, J. G. J. Am. Chem. Soc. 2001,
123, 11933. (b) Kornienko, A.; Melman, J. H.; Hall, G.; Emge, T. J.;
Brennan, J. G. Inorg. Chem. 2002, 41, 121.
(21) (a) Petragnani, N.; DeMoura, M. Chem. Ber. 1963, 96, 249. (b) Haller,
W. S.; Irgolic, K. J. J. Organomet. Chem. 1973, 38, 97.
(22) Pardo, M. P.; Flahaut, J.; Domange, L. Bull. Chem. Soc. Fr. 1963,
256, 953.
Inorganic Chemistry, Vol. 41, No. 3, 2002 493

Freedman et al.
Table 1. Summary of Crystallographic Details for 1, 2, and 4a
compound
1
2
4
empirical formula
fw
space group (No.)
a (Å)
b (Å)
C82H80N14Sm4Te11
3266.60
P21/n (14)
12.191(5)
27.484(5)
28.484(5)
90.00
91.56(2)
90.00
9540(5)
4
2.274
-120
0.71073
5.770
0.066
0.152
C64.50H62.50N10.50Tb4Te11.12
3039.98
P21/c (14)
12.85(1)
31.13(1)
20.37(1)
90.00(5)
91.50(5)
90.00(5)
8146(8)
4
2.479
-120
0.71073
7.378
0.067
0.155
C57H55N9Te11.62Tm4
3025.17
C2 (5)
23.407(7)
23.20(2)
17.507(9)
90.00
113.38(4)
90.00
8728(9)
4
2.302
-120
0.71073
7.869
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
D(calcd) (g/cm-3
temperature (°C)
λ (Å)
)
abs coeff (mm-1
)
R(F)b [I > 2σ(I)]
0.091
0.221
Rw(F2)b [I > 2σ(I)]
2
2
a Additional crystallographic details are given in the Supporting Information. b R(F) ) ∑||Fo| - |Fc||/∑|Fo|; Rw(F2) ) {∑[w(Fo2 - Fc )2]/∑[w(Fo )2]}1/2
.
(w) cm-1. Magnetic susceptibility: µeff (5-250 K) ) 10.6 (500
G); 10.4 (10 kG). Unit cell (Mo KR, -120 °C): monoclinic space
group P21/c, a ) 12.775(3) Å, b ) 31.326(12) Å, c ) 20.113(3)
Å, â ) 91.55 (2)°, V ) 8046(4) Å3 determined from 25 reflections
(w), 1632 (w), 1596 (m), 1579 (m), 1437 (s), 1366 (s), 1216 (m),
1145 (m), 1068 (m), 1030 (m), 990 (m), 745 (m), 702 (s), 606 (m)
cm-1. Magnetic susceptibility: µeff (5-250 K) ) 7.65 µB (500 G,
C ) 5.87); 7.24 µB (10 kG, C ) 6.56). The compound does not
show an absorption maximum from 350 to 800 nm in pyridine. 1H
NMR (THF) revealed only displaced pyridine resonances at 8.61,
7.65, 7.28 ppm. Thermolysis: The compound was treated as in 1.
X-ray powder diffraction analysis identified TmTe24 as the only
crystalline Ln-containing product of the reaction, and GCMS
identified Ph2Te as the only organic product.
X-ray Structure Determination of 1, 2, and 4. Data for 1, 2,
and 4 were collected on an Enraf-Nonius CAD4 diffractometer with
graphite-monochromatized Mo KR radiation (λ ) 0.71073 Å) at
-120 °C. Samples must be completely cooled before exposure to
any X-ray source. The check reflections measured every hour
showed less than 3% intensity variation. The data were corrected
for Lorenz effects, polarization, and absorption, the latter by a
numerical (SHELX76)25 method. The structures were solved by
Patterson methods (SHELXS86).26 All non-hydrogen atoms were
refined (SHELXL97) based upon Fobs2. All hydrogen atom coor-
dinates were calculated with idealized geometries (SHELXL97).27
Scattering factors (fo, f′, f′′) are as described in SHELXL97.
Crystallographic data and final R indices for 1, 2, and 4 are
given in Table 1. Significant bond distances and angles for 1, 2,
and 4 are given in Tables 2, 3, and 4, respectively. Complete
crystallographic details are given in the Supporting Information.
ORTEP diagrams28 for 1, 2, and 4 are shown in Figures 1-3,
respectively.
1
with 13.1° < θ < 16.4°. The H NMR spectrum contained only
pyridine resonances at 8.54, 7.66, and 7.23 ppm. The compound
does not show an absorption maximum from 350 to 800 nm in
either THF or pyridine. Thermolysis: 100 mg of the sample was
placed in a quartz tube under vacuum for 5 min. The tube was
then sealed and the sample temperature was increased at the rate
of 20 °C/min with one end of the tube submerged in liquid nitrogen.
The temperature was kept between 475 and 490 °C for 5 h. The
quartz tube was removed and allowed to cool at room temperature.
Powder diffraction X-ray analysis of the nonvolatile black powder
revealed only HoTe.23 Analysis of the residue by GCMS identified
Ph2Te as the only organic product of the reaction.
Method 2. Holmium metal (0.33 g, 2 mmol) and Hg (0.05 g,
0.25 mmol) were added to a solution of diphenyl ditelluride (0.82
g, 2.0 mmol) in pyridine (50 mL). The flask was wrapped in
aluminum foil up to the neck, and after 1 day elemental tellurium
(0.38 g, 3.0 mmol) was added to the yellow solution that still
contained unreacted metal. Two days later all the metal had reacted
and there was a significant amount of dark red precipitate. After
heating (60-75 °C, 1 h) to dissolve the precipitate, the solution
was filtered to a flask with either a flat bottom (modified
Erlenmeyer) or a large round-bottom that was shielded from light.
The volume was reduced by ca. 3 mL and then saturated by rapid
addition of ca. 8 mL of hexanes. After 2 days, dark red crystals
(0.45 g, 46%) were collected.
Results
Synthesis of (py)7Tm4(µ4-Te)[(TeTe)4TePh](Te0.6TePh)·2py
(4). Thulium metal (0.34 g, 2.0 mmol), Hg (0.05 mg, 0.25 mmol),
and PhTeTePh (0.82 g, 2.0 mmol) were added to pyridine (50 mL),
the flask was wrapped in aluminum foil, and the mixture was stirred.
After 1 day, elemental tellurium (380 mg, 3.0 mmol) was added to
the dark red solution that still contained unreacted Tm. Two days
later the metal had reacted and there was a significant amount of
dark red precipitate. The flask was heated (60-75 °C) for ca. 1 h
until all the red precipitate redissolved. The red solution was filtered
and saturated as above to give deep red crystals (0.45 g, 46%) that
did not melt up to 300 °C but slowly desolvated and darkened above
200 °C. If the crystals are not dried thoroughly before the melting
point determination, they do not melt but begin turning gray at ca.
180 °C and become more silver/gray and flaky by 250 °C. Anal.
Calcd for C57H55N9Tm4Te11.6: C, 22.6; H, 1.83; N, 4.17. Found:
C, 23.2; H, 2.13; N, 3.90. IR: 2923 (s), 1978 (w), 1941 (w), 1864
Lanthanide tellurido clusters (py)8Ln4(µ4-Te)(µ2-TeTe)2-
(µ2-η2,η2-Te5Ph)(Te0.1TePh) [Ln ) Tb(2), Ho(3)] can be
(23) The XRPD profile of the Ho thermolysis product matched that for
TbTe: Cannon, J.; Hall, H. Inorg. Chem. 1970, 9, 1639
(24) (a) Dismuskes, J. P.; White, J. G. Inorg. Chem. 1965, 4, 970. (b)
Brixner, L. H. J. Inorg. Nucl. Chem. 1960, 15, 199. (c) Devi, S. U.;
Singh, S. Solid State Commun. 1984, 52, 303.
(25) Sheldrick, G. M. SHELX76, Program for Crystal Structure Determi-
nation, University of Cambridge, England, 1976.
(26) Sheldrick, G. M. SHELXS86, Program for the Solution of Crystal
Structures, University of Go¨ttingen, Germany, 1986.
(27) Sheldrick, G. M. SHELXL97, Program for Crystal Structure Refine-
ment, University of Go¨ttingen, Germany, 1997.
(28) (a) Johnson, C. K.; ORTEP II, Report ORNL-5138. Oak Ridge
National Laboratory, Oak Ridge, TN, 1976. (b) Zsolnai, L. XPMA
and ZORTEP, Programs for Interactive ORTEP Drawings, University
of Heidelberg, Germany, 1997.
494 Inorganic Chemistry, Vol. 41, No. 3, 2002

Chalcogen-Rich Lanthanide Clusters
Table 2. Significant Distances (Å) and Angles (deg) for 1
Sm(1)-N(1)
Sm(1)-Te(1)
Sm(1)-Te(4)
Sm(2)-N(3)
Sm(2)-Te(6)
Sm(2)-Te(1)
Sm(3)-N(6)
Sm(3)-Te(6)
Sm(4)-N(8)
Sm(4)-Te(1)
Sm(4)-Te(2)
Te(4)-Te(5)
Te(7)-Te(10)
2.591(17)
3.1208(18)
3.1599(18)
2.663(17)
3.1498(18)
3.2316(18)
2.673(16)
3.1702(18)
2.571(17)
3.0753(18)
3.1678(18)
2.764(2)
Sm(1)-Te(11)
Sm(1)-Te(2)
Sm(2)-N(2B)
Sm(2)-N(2A)
Sm(2)-Te(5)
Sm(3)-N(5)
Sm(3)-Te(7)
Sm(3)-Te(8)
Sm(4)-N(9)
Sm(4)-Te(3)
Te(2)-Te(3)
Te(5)-Te(10)
Te(8)-Te(9)
3.067(2)
3.1261(18)
2.63(2)
Sm(1)-Te(5)
Sm(1)-Te(3
Sm(2)-N(4)
Sm(2)-Te(7)
Sm(2)-Te(4)
Sm(3)-N(7)
Sm(3)-Te(9)
Sm(3)-Te(1)
Sm(4)-Te(9)
Sm(4)-Te(8)
Te(3)-Te(10)
Te(6)-Te(7)
Te(9)-Te(10)
3.1079(19)
3.1274(18)
2.647(17)
3.1150(18)
3.2248(18)
2.662(18)
3.1436(18)
3.2740(18)
3.0583(18)
3.0998(18)
3.849(2)
2.67(2)
3.1517(18)
2.620(17)
3.130(2)
3.1792(19)
2.583(17)
3.100(2)
2.771(2)
3.617(2)
2.940(2)
2.909(2)
3.085(2)
3.156(2)
N(1)-Sm(1)-Te(11)
Te(11)-Sm(1)-Te(5)
Te(11)-Sm(1)-Te(1)
N(1)-Sm(1)-Te(2)
Te(5)-Sm(1)-Te(2
N(1)-Sm(1)-Te(3)
Te(5)-Sm(1)-Te(3)
Te(2)-Sm(1)-Te(3)
Te(11)-Sm(1)-Te(4)
Te(1)-Sm(1)-Te(4)
Te(5)-Sm(1)-Te(4)
Te(2)-Sm(1)-Te(4)
N(2B)-Sm(2)-N(4)
N(4)-Sm(2)-N(3)
N(4)-Sm(2)-N(2A)
N(2B)-Sm(2)-Te(7)
N(3)-Sm(2)-Te(7)
N(2B)-Sm(2)-Te(6)
N(3)-Sm(2)-Te(6)
Te(7)-Sm(2)-Te(6)
N(4)-Sm(2)-Te(5)
N(2A)-Sm(2)-Te(5)
Te(6)-Sm(2)-Te(5)
N(4)-Sm(2)-Te(4)
N(2A)-Sm(2)-Te(4)
Te(6)-Sm(2)-Te(4)
N(2B)-Sm(2)-Te(1)
N(3)-Sm(2)-Te(1)
Te(7)-Sm(2)-Te(1)
Te(5)-Sm(2)-Te(1)
84.9(4)
N(1)-Sm(1)-Te(5)
86.0(4)
N(5)-Sm(3)-N(7)
N(7)-Sm(3)-N(6)
N(7)-Sm(3)-Te(7)
N(5)-Sm(3)-Te(9)
N(6)-Sm(3)-Te(9)
N(5)-Sm(3)-Te(6)
N(6)-Sm(3)-Te(6)
Te(9)-Sm(3)-Te(6)
N(7)-Sm(3)-Te(8)
Te(7)-Sm(3)-Te(8)
Te(6)-Sm(3)-Te(8)
N(7)-Sm(3)-Te(1)
Te(7)-Sm(3)-Te(1)
Te(6)-Sm(3)-Te(1)
N(8)-Sm(4)-N(9)
N(9)-Sm(4)-Te(9)
N(9)-Sm(4)-Te(1)
N(8)-Sm(4)-Te(3)
Te(9)-Sm(4)-Te(3)
N(8)-Sm(4)-Te(8)
Te(9)-Sm(4)-Te(8)
Te(3)-Sm(4)-Te(8)
N(9)-Sm(4)-Te(2)
Te(1)-Sm(4)-Te(2)
Te(8)-Sm(4)-Te(2)
C(1)-Te(10)-Te(7)
C(1)-Te(10)-Te(5)
Te(7)-Te(10)-Te(5)
Te(9)-Te(10)-Te(3)
Te(5)-Te(10)-Te(3)
132.8(5)
67.9(5)
75.7(4)
137.6(4)
124.2(4)
84.2(4)
92.8(4)
130.71(5)
94.1(4)
131.14(5)
173.75(5)
151.9(4)
80.14(4)
89.00(4)
89.8(5)
140.4(4)
91.5(4)
84.0(4)
82.33(5)
89.1(4)
57.03(5)
137.83(5)
84.9(4)
89.93(5)
167.42(5)
102.5(6)
146.7(6)
69.99(4)
70.58(5)
73.92(4)
N(5)-Sm(3)-N(6)
65.9(5)
128.40(6)
105.60(6)
91.4(4)
144.66(5)
82.5(4)
92.19(5)
52.60(4)
76.95(5)
92.05(5)
52.32(4)
163.02(5)
66.0(8)
65.2(5)
68.1(7)
134.1(7)
79.7(4)
87.3(7)
N(1)-Sm(1)-Te(1)
Te(5)-Sm(1)-Te(1)
Te(11)-Sm(1)-Te(2)
Te(1)-Sm(1)-Te(2)
Te(11)-Sm(1)-Te(3)
Te(1)-Sm(1)-Te(3)
N(1)-Sm(1)-Te(4)
Te(5)-Sm(1)-Te(4)
Te(11)-Sm(1)-Te(4)
Te(1)-Sm(1)-Te(4)
Te(3)-Sm(1)-Te(4)
N(2B)-Sm(2)-N(3)
N(2B)-Sm(2)-N(2A)
N(3)-Sm(2)-N(2A)
N(4)-Sm(2)-Te(7)
N(2A)-Sm(2)-Te(7)
N(4)-Sm(2)-Te(6)
N(2A)-Sm(2)-Te(6)
N(2B)-Sm(2)-Te(5)
N(3)-Sm(2)-Te(5)
Te(7)-Sm(2)-Te(5)
N(2B)-Sm(2)-Te(4)
N(3)-Sm(2)-Te(4)
Te(7)-Sm(2)-Te(4)
Te(5)-Sm(2)-Te(4)
N(4)-Sm(2)-Te(1)
N(2A)-Sm(2)-Te(1)
Te(6)-Sm(2)-Te(1)
Te(4)-Sm(2)-Te(1)
169.5(4)
86.91(5)
86.28(5)
89.87(5)
136.34(5)
90.04(5)
89.8(4)
52.32(4)
76.95(5)
92.05(5)
144.23(5)
131.1(8)
2.3(12)
133.3(7)
130.4(4)
133.7(7)
89.5(4)
88.3(7)
134.5(7)
78.1(4)
77.04(5)
88.7(7)
92.4(4)
128.20(5)
51.35(4)
138.5(4)
70.4(6)
90.12(5)
88.87(5)
N(5)-Sm(3)-Te(7)
N(6)-Sm(3)-Te(7)
N(7)-Sm(3)-Te(9)
Te(7)-Sm(3)-Te(9)
N(7)-Sm(3)-Te(6)
Te(7)-Sm(3)-Te(6)
N(5)-Sm(3)-Te(8)
N(6)-Sm(3)-Te(8)
Te(9)-Sm(3)-Te(8)
N(5)-Sm(3)-Te(1)
N(6)-Sm(3)-Te(1)
Te(9)-Sm(3)-Te(1)
Te(8)-Sm(3)-Te(1)
N(8)-Sm(4)-Te(9)
N(8)-Sm(4)-Te(1)
Te(9)-Sm(4)-Te(1)
N(9)-Sm(4)-Te(3)
Te(1)-Sm(4)-Te(3)
N(9)-Sm(4)-Te(8)
Te(1)-Sm(4)-Te(8)
N(8)-Sm(4)-Te(2)
Te(9)-Sm(4)-Te(2)
Te(3)-Sm(4)-Te(2)
C(1)-Te(10)-Te(9)
Te(9)-Te(10)-Te(7)
Te(9)-Te(10)-Te(5)
C(1)-Te(10)-Te(3)
Te(7)-Te(10)-Te(3)
132.1(4)
131.7(4)
78.6(4)
75.73(5)
88.8(4)
54.98(4)
89.8(4)
83.3(4)
55.42(4)
74.7(4)
140.2(4)
81.75(4)
90.97(4)
95.9(4)
174.5(4)
86.46(5)
137.2(4)
91.41(5)
84.1(4)
96.36(5)
84.9(4)
134.55(5)
52.46(4)
94.4(6)
76.20(5)
113.99(5)
135.0(6)
113.75(5)
90.1(4)
55.32(4)
124.4(4)
132.7(7)
132.30(5)
88.7(4)
87.8(7)
176.06(5)
72.6(7)
156.3(4)
81.03(5)
84.29(5)
isolated as pure materials in 35-45% yields from the
reactions of elemental Ln with PhTeTePh and Te in pyridine
(reaction 1).
structure appears general for the middle of the lanthanide
series, limits are imposed at Sm, which requires manual
isolation, and at Yb, which does not form stable Ln(III)
compounds with only Te-based anions.29
4Ln + 2PhTeTePh + 9Te f
The general structures of 1 and 2 contain a square array
of Ln(III) ions all connected to a central Te2-. Two edges
of the square are bridged by (TeTe)2-, and the Ln coordinat-
ing both of these (TeTe)2- ligands is also coordinated to a
terminal TePh. The remaining two edges of the square are
also bridged by (TeTe)2-, but the second TePh moiety has
been displaced from a Ln coordination site and instead bonds
to two TeTe ligands in a variable fashion, to give what is
formally (TeTeTe(Ph)TeTe).5- There is a broad range of
interactions between TePh and the TeTe units, as illustrated
in Figure 4: in 1, there are two clearly asymmetric bonds to
TeTe (differing by 0.07 Å), and the third nearest TeTe unit
is a further 0.46 Å away. In 2, which has a detectable amount
of TeTePh substituting for the terminal TePh, the displaced
TePh ligand coordinates the two TeTe units with greater
asymmetry (0.28 Å), and the next nearest TeTe is only 0.34
Å further away from the “Te5Ph” moiety.
(py)8Ln4(Te)(TeTe)2(Te5Ph)(Te0.1TePh) (1)
These compounds cocrystallize with ca. 10% of the tetra-
metallic cluster containing an additional Te atom inserted
into the Ln-TePh bond. The isomorphous Sm cluster
(py)9Sm4(Te)(TeTe)2(Te5Ph)(TePh) (1) can also be prepared,
but has not yet been isolated (other than by hand) in pure
form. Structural characterization of 1 reveals it to be
isomorphous with 2 and 3, but without the compositional
disorder in the terminal TePh site. A related Tm cluster
(py)7Tm4(µ4-Te)[(TeTe)4TePh](Te0.6TePh) (4) can also be
prepared, and again, the product is similarly disordered, with
a TeTePh/TePh occupancy of 62:38. In all compositionally
disordered structures, lattice pyridine is also disordered
between two positions, with site occupancies that are directly
related to the percentage of inserted Te.
These compounds are sensitive to oxygen and water, they
desolvate when isolated at room temperature, and are
sensitive to light throughout the synthetic process. While this
(29) Flahaut, J.; Laruelle, P.; Pardo, M.; Guittard, M. Bull Chem. Soc. Fr.
1965, 1399.
Inorganic Chemistry, Vol. 41, No. 3, 2002 495

Freedman et al.
Table 3. Significant Distances (Å) and Angles (deg) for 2
Tb(1)-N(2)
Tb(1)-Te(3)
Tb(1)-Te(2)
Tb(2)-Te(4)
Tb(2)-Te(5)
Tb(3)-N(4)
Tb(3)-Te(1)
Tb(4)-N(6)
Tb(4)-Te(8)
Tb(4)-Te(6)
Te(3)-Te(10)
Te(6)-Te(7)
Te(9)-Te(10)
2.51(2)
Tb(1)-N(1)
Tb(1)-Te(1)
Tb(2)-N(3)
Tb(2)-Te(2)
Tb(2)-Te(1)
Tb(3)-Te(7)
Tb(3)-Te(6)
Tb(4)-N(7)
Tb(4)-Te(7)
Tb(4)-Te(1)
Te(4)-Te(5)
Te(7)-Te(10)
2.561(19)
3.050(3)
2.55(2)
3.078(3)
3.136(3)
3.006(3)
3.127(3)
2.57(2)
3.132(3)
3.317(3)
2.772(3)
3.327(3)
Tb(1)-Te(9)
Tb(1)-Te(8)
Tb(2)-Te(11)
Tb(2)-Te(3)
Tb(3)-N(5)
Tb(3)-Te(5)
Tb(3)-Te(4)
Tb(4)-N(8)
Tb(4)-Te(9)
Te(2)-Te(3)
Te(5)-Te(10)
Te(8)-Te(9)
3.021(3)
3.077(3)
2.994(3)
3.086(3)
2.456(19)
3.020(3)
3.151(3)
2.63(2)
3.137(3)
2.762(3)
3.665(3)
2.960(3)
3.046(3)
3.141(3)
3.073(3)
3.127(3)
2.52(2)
3.042(3)
2.560(18)
3.113(3)
3.144(3)
3.836(4)
2.843(3)
3.051(3)
N(2)-Tb(1)-N(1)
N(1)-Tb(1)-Te(9)
N(1)-Tb(1)-Te(3)
N(2)-Tb(1)-Te(1)
Te(9)-Tb(1)-Te(1)
N(2)-Tb(1)-Te(8)
Te(9)-Tb(1)-Te(8)
Te(1)-Tb(1)-Te(8)
N(1)-Tb(1)-Te(2)
Te(3)-Tb(1)-Te(2)
Te(8)-Tb(1)-Te(2)
N(3)-Tb(2)-Te(4)
N(3)-Tb(2)-Te(2)
Te(4)-Tb(2)-Te(2)
Te(11)-Tb(2)-Te(3)
Te(2)-Tb(2)-Te(3)
Te(11)-Tb(2)-Te(5)
Te(2)-Tb(2)-Te(5)
N(3)-Tb(2)-Te(1)
Te(4)-Tb(2)-Te(1)
Te(3)-Tb(2)-Te(1)
N(5)-Tb(3)-N(4)
N(4)-Tb(3)-Te(7)
87.3(7)
98.5(4)
86.9(5)
88.4(5)
87.35(7)
85.4(5)
58.07(7)
95.25(7)
85.2(4)
53.01(6)
166.93(6)
92.3(4)
N(2)-Tb(1)-Te(9)
142.5(5)
135.9(5)
81.47(7)
174.1(4)
93.39(7)
88.4(4)
138.02(7)
83.0(5)
134.20(7)
90.33(7)
91.3(5)
73.71(8)
89.00(8)
81.3(5)
144.18(7)
86.2(5)
53.10(6)
91.19(7)
98.51(8)
89.93(7)
87.80(7)
141.1(5)
137.4(5)
N(4)-Tb(3)-Te(5)
N(5)-Tb(3)-Te(1)
Te(7)-Tb(3)-Te(1)
N(5)-Tb(3)-Te(6)
Te(7)-Tb(3)-Te(6)
Te(1)-Tb(3)-Te(6)
N(4)-Tb(3)-Te(4)
Te(5)-Tb(3)-Te(4)
Te(6)-Tb(3)-Te(4)
N(6)-Tb(4)-N(8)
N(6)-Tb(4)-Te(8)
N(8)-Tb(4)-Te(8)
N(7)-Tb(4)-Te(7)
Te(8)-Tb(4)-Te(7)
N(7)-Tb(4)-Te(9)
Te(7)-Tb(4)-Te(9)
N(7)-Tb(4)-Te(6)
Te(8)-Tb(4)-Te(6)
Te(9)-Tb(4)-Te(6)
N(7)-Tb(4)-Te(1)
Te(8)-Tb(4)-Te(1)
Te(9)-Tb(4)-Te(1)
90.7(5)
90.3(5)
Te(7)-Tb(3)-Te(5)
81.49(7)
169.8(5)
91.50(7)
91.5(5)
136.22(7)
84.1(5)
134.81(7)
90.66(7)
67.0(6)
70.0(6)
89.3(5)
77.9(4)
131.3(5)
77.9(4)
133.7(5)
93.3(4)
85.9(5)
53.87(6)
154.2(4)
68.9(4)
82.35(7)
88.37(7)
N(2)-Tb(1)-Te(3)
Te(9)-Tb(1)-Te(3)
N(1)-Tb(1)-Te(1)
Te(3)-Tb(1)-Te(1)
N(1)-Tb(1)-Te(8)
Te(3)-Tb(1)-Te(8)
N(2)-Tb(1)-Te(2)
Te(9)-Tb(1)-Te(2)
Te(1)-Tb(1)-Te(2)
N(3)-Tb(2)-Te(11)
Te(11)-Tb(2)-Te(4)
Te(11)-Tb(2)-Te(2)
N(3)-Tb(2)-Te(3)
Te(4)-Tb(2)-Te(3)
N(3)-Tb(2)-Te(5)
Te(4)-Tb(2)-Te(5
Te(3)-Tb(2)-Te(5)
Te(11)-Tb(2)-Te(1)
Te(2)-Tb(2)-Te(1
Te(5)-Tb(2)-Te(1)
N(5)-Tb(3)-Te(7)
N(5)-Tb(3)-Te(5)
N(4)-Tb(3)-Te(1)
Te(5)-Tb(3)-Te(1)
N(4)-Tb(3)-Te(6)
Te(5)-Tb(3)-Te(6)
N(5)-Tb(3)-Te(4)
Te(7)-Tb(3)-Te(4)
Te(1)-Tb(3)-Te(4)
N(6)-Tb(4)-N(7)
N(7)-Tb(4)-N(8)
N(7)-Tb(4)-Te(8)
N(6)-Tb(4)-Te(7)
N(8)-Tb(4)-Te(7)
N(6)-Tb(4)-Te(9)
N(8)-Tb(4)-Te(9)
N(6)-Tb(4)-Te(6)
N(8)-Tb(4)-Te(6)
Te(7)-Tb(4)-Te(6)
N(6)-Tb(4)-Te(1)
N(8)-Tb(4)-Te(1)
Te(7)-Tb(4)-Te(1)
Te(6)-Tb(4)-Te(1)
89.26(7)
86.0(5)
55.21(6)
93.84(8)
82.7(5)
53.33(7)
169.17(6)
137.0(6)
91.2(4)
88.0(5)
90.3(4)
126.7(4)
131.45(7)
130.3(6)
74.92(6)
88.6(5)
173.82(6)
128.67(7)
138.8(5)
89.42(7)
80.96(7)
162.55(7)
141.18(7)
53.25(6)
126.54(8)
144.33(7)
170.1(5)
90.36(7)
90.96(7)
81.4(7)
100.9(5)
Coordination of TePh to (TeTe)2- effectively decreases
the (TeTe)2- bond length, and the magnitude of the length-
ening is inversely proportional to the intensity of the
PhTe-(TeTe) interaction, as judged by the length of the
PhTe-TeTe bond (Figure 4). For 1, TePh has a bond to
Te(9) that is 0.71 Å shorter than the bond to Te(7), and
the Te(9)-Te(8) bond is longer, by 0.031(1) Å, than the
Te(7)-Te(6) bond. More dramatically, in 2 the bond from
PhTe to Te(9) is 0.276 Å shorter than the bond to Te(7),
and the Te(9)-Te(8) bond is significantly longer, by 0.117-
(3) Å, than the Te(7)-Te(6) bond. In both 1 and 2, the TeTe
ligands that do not interact with TePh have TeTe bond
lengths within a well-defined range [2.762(2)-2.772(3) Å]
of values.
Cluster 4 is more complex, with significantly weaker
interactions between the displaced TePh and the two remain-
ing TeTe units, leading to an alternative description of the
anionic tellurium fragment as a (Te9Ph)9- ligand. In 4, the
TePh coordinates more strongly to Te(7) and Te(9), and again
these ditelluride units have TeTe bonds ca. 0.1 Å longer than
the “uninvolved” TeTe ligands in 1 and 2. In addition, there
are additional “bonds” from TePh to Te(5) and Te(3) that
are only ca. 0.2 Å longer than those to Te(7) and Te(9). In
one of these ligands, there is a clear lengthening of the Te-
(5)-Te(4) bond, to 2.834(11) Å, while in the second ligand
the bond [Te(3)-Te(2), 2.795(11) Å] is less influenced by
coordination to the central TePh. Again, in both of these
weaker interactions, the lengthening of the TeTe bond is
inversely proportional to the length of the PhTe-TeTe bond.
The multitude of allowed electronic transitions that are
entirely ligand based, as well as Te to Ln charge-transfer
excitations, produce a featureless visible spectrum when the
compounds are redissolved in pyridine. Magnetic susceptibil-
ity measurements indicate that there are no interactions
between neighboring Ln(III) ions. Measurements of ø vs T
were obtained for 3 and 4 and are plotted in Figures 5 and
6, respectively. The ø-1 results reveal distinct Curie Weiss
(CW) behavior [ø ) C /(θ + T)] for both compounds at all
temperatures.
Numerous LnTex phases were observed in the thermal
decomposition of 2-4. Both 3 and 4 decompose to give
LnTe (reaction 2)
(py)xLn4(Te)(TeTe)2(Te5Ph)(TePh) f
LnTex + Te + Ph2Te + py (2)
with elimination of TePh2 and Te. Under identical conditions
the Tb compound 2 gives TbTe2-x. Phase purity of the final
solid-state product depends significantly on the thermolysis
conditions. If 4 is heated at 550 °C and then cooled slowly,
three products (TmTe, TmTe3, and Tm2Te3) are detected by
XRPD. In contrast, if the sample is first heated and then
cooled immediately, TmTe is the only crystalline product
observed in the XRPD profile. Again, TePh2 was identified
as the only volatile product by GCMS.
Discussion
The comparative ease with which polytellurido compounds
of the lanthanides can be isolated, relative to the synthesis
496 Inorganic Chemistry, Vol. 41, No. 3, 2002

Chalcogen-Rich Lanthanide Clusters
Table 4. Significant Distances (Å) and Angles (deg) for 4
Tm(1)-N(1)
Tm(1)-Te(1A)
Tm(1)-Te(1)
Tm(2)-Te(5)
Tm(2)-Te(6)
Tm(3)-N(4)
Tm(3)-Te(8)
Tm(4)-N(7)
Tm(4)-Te(9)
Tm(4)-Te(2)
Te(4)-Te(5)
Te(7)-Te(10)
2.50(2)
Tm(1)-Te(2)
Tm(1)-Te(4)
Tm(2)-N(3)
Tm(2)-Te(1)
Tm(2)-Te(4)
Tm(3)-Te(9)
Tm(3)-Te(1)
Tm(4)-N(6)
Tm(4)-Te(8)
Te(2)-Te(3)
Te(5)-Te(10)
Te(8)-Te(9)
2.993(10)
3.060(10)
2.52(3)
3.018(8)
3.066(7)
2.984(7)
3.101(3)
2.43(3)
3.044(7)
2.795(10)
3.521(9)
2.836(9)
Tm(1)-Te(3)
Tm(1)-Te(5)
Tm(2)-N(2)
Tm(2)-Te(7)
Tm(3)-N(5)
Tm(3)-Te(7)
Tm(3)-Te(6)
Tm(4)-Te(3)
Tm(4)-Te(1)
Te(3)-Te(10)
Te(6)-Te(7)
Te(9)-Te(10)
3.000(8)
3.092(9)
2.51(4)
3.033(4)
3.130(3)
2.993(8)
3.056(7)
2.481(17)
3.024(8)
2.37(3)
3.036(7)
3.097(7)
2.834(11)
3.292(9)
3.030(8)
2.415(18)
3.005(7)
3.101(8)
3.008(8)
3.081(8)
3.543(9)
2.872(10)
3.336(9)
N(1)-Tm(1)-Te(2)
Te(2)-Tm(1)-Te(3)
93.6(10)
55.6(2)
N(1)-Tm(1)-Te(3)
N(1)-Tm(1)-Te(1A)
90.4(9)
90.8(7)
N(5)-Tm(3)-N(4)
N(4)-Tm(3)-Te(9)
N(4)-Tm(3)-Te(7)
83.1(8)
N(5)-Tm(3)-Te(9)
N(5)-Tm(3)-Te(7)
136.2(9)
139.2(9)
90.0(8)
89.3(7)
80.5(9)
Te(2)-Tm(1)-Te(1A) 85.4(3)
Te(3)-Tm(1)-Te(1A) 141.0(3)
Te(9)-Tm(3)-Te(7) 83.53(10)
N(4)-Tm(3)-Te(8) 90.8(9)
Te(7)-Tm(3)-Te(8) 139.9(2)
N(4)-Tm(3)-Te(1) 178.8(8)
Te(9)-Tm(3)-Te(1) 90.18(16) Te(7)-Tm(3)-Te(1) 89.48(16)
83.8(9)
N(1)-Tm(1)-Te(4)
Te(3)-Tm(1)-Te(4)
N(1)-Tm(1)-Te(5)
Te(3)-Tm(1)-Te(5)
Te(4)-Tm(1)-Te(5)
Te(2)-Tm(1)-Te(1)
86.7(10)
140.4(2)
85.2(9)
Te(2)-Tm(1)-Te(4)
163.98(12) N(5)-Tm(3)-Te(8)
Te(1A)-Tm(1)-Te(4) 78.5(3)
Te(9)-Tm(3)-Te(8) 56.3(2)
N(5)-Tm(3)-Te(1) 97.6(6)
Te(2)-Tm(1)-Te(5)
141.2(2)
85.57(12) Te(1A)-Tm(1)-Te(5) 133.3(3)
54.9(2)
90.9(2)
N(1)-Tm(1)-Te(1)
Te(3)-Tm(1)-Te(1)
Te(4)-Tm(1)-Te(1)
174.3(9)
89.31(19)
89.9(2)
85.5(16)
139.5(12)
90.8(12)
92.0(10)
82.1(2)
87.5(10)
138.2(3)
56.3(2)
83.9(12)
91.94(19)
165.2(3)
Te(8)-Tm(3)-Te(1) 90.37(19) N(5)-Tm(3)-Te(6)
N(4)-Tm(3)-Te(6)
89.7(9)
Te(9)-Tm(3)-Te(6) 139.6(2)
Te(1A)-Tm(1)-Te(1) 92.99(9)
Te(7)-Tm(3)-Te(6) 56.1(2)
Te(1)-Tm(3)-Te(6) 89.4(2)
Te(8)-Tm(3)-Te(6) 164.06(9)
Te(5)-Tm(1)-Te(1)
N(3)-Tm(2)-Te(5)
N(3)-Tm(2)-Te(1)
Te(5)-Tm(2)-Te(1)
N(2)-Tm(2)-Te(7)
Te(1)-Tm(2)-Te(7)
N(2)-Tm(2)-Te(6)
Te(1)-Tm(2)-Te(6)
N(3)-Tm(2)-Te(4)
Te(5)-Tm(2)-Te(4)
Te(7)-Tm(2)-Te(4)
89.08(18) N(3)-Tm(2)-N(2)
89.7(9) N(2)-Tm(2)-Te(5)
N(7)-Tm(4)-N(6)
85.9(15)
93.2(10)
90.7(10)
86.1(11)
N(7)-Tm(4)-Te(3)
N(7)-Tm(4)-Te(9)
135.8(11) N(6)-Tm(4)-Te(3)
141.7(11) N(6)-Tm(4)-Te(9)
176.4(10) N(2)-Tm(2)-Te(1)
93.11(19) N(3)-Tm(2)-Te(7)
138.1(12) Te(5)-Tm(2)-Te(7)
90.60(16) N(3)-Tm(2)-Te(6)
Te(3)-Tm(4)-Te(9) 82.5(2)
N(7)-Tm(4)-Te(8)
Te(3)-Tm(4)-Te(8) 138.1(2)
N(6)-Tm(4)-Te(8)
Te(9)-Tm(4)-Te(8) 55.60(18) N(7)-Tm(4)-Te(1)
N(6)-Tm(4)-Te(1) 176.7(10) Te(3)-Tm(4)-Te(1) 90.11(19)
Te(9)-Tm(4)-Te(1) 89.61(18) Te(8)-Tm(4)-Te(1) 90.40(16)
81.3(11) 92.1(10)
87.1(10)
91.8(11)
81.8(12)
Te(5)-Tm(2)-Te(6)
91.81(16) Te(7)-Tm(2)-Te(6)
87.8(10)
55.8(2)
N(2)-Tm(2)-Te(4)
Te(1)-Tm(2)-Te(4)
Te(6)-Tm(2)-Te(4)
N(7)-Tm(4)-Te(2)
N(6)-Tm(4)-Te(2)
Te(9)-Tm(4)-Te(2) 137.0(3)
Te(1)-Tm(4)-Te(2) 89.90(17)
Te(3)-Tm(4)-Te(2) 54.5(2)
Te(8)-Tm(4)-Te(2) 167.4(3)
137.9(3)
Figure 1. ORTEP diagram of (py)9SmTe(TeTe)2(TeTeTe(Ph)TeTe)(TePh)
with the C and H atoms removed for clarity and with the thermal ellipsoids
drawn at the 50% probability level.
of Ln clusters with Te2-, suggests that the ditellurido ligand
stabilizes Ln(III) ions more effectively than Te2-. These
compounds can be prepared either by first adding PhTeTePh
to Ln, followed by addition of Te, or in a one-step reaction.
Absence of light throughout the synthetic procedure is crucial
to the successful isolation of these cluster compounds, as
found in the synthesis of tellurolate-capped tellurido clusters
of the transition metals.30 When solutions of the initial
insertion of Ln into the PhTe-TePh bond were exposed to
light and the reaction was then insulated, no product was
recovered. Similarly, when the first insertion step was
insulated but the reaction was then exposed to light, no
product formed. The compounds are also light-sensitive after
isolation and will turn from red to black within hours under
ambient conditions.
Figure 2. ORTEP diagram of (py)8TbTe(TeTe)2(TeTeTe(Ph)TeTe)-
(Te0.1TePh) with the C and H atoms removed for clarity and with the thermal
ellipsoids drawn at the 50% probability level.
Clusters 1-4 share the same fundamental structural
features recently reported for the sulfur-rich iodo cluster
(THF)6Yb4(SS)4(S)I2,19 with a square array of Ln(III) ions,
the central chalcogenido ligand, and two edges spanned by
TeTe units. The central Te2- resides 1.00 Å (1), 1.11 Å (2),
or 1.17 Å (4) above the plane defined by the Ln4 core. When
corrected for differences in Ln ionic radii,31 the terminal
tellurolate Ln-Te bond lengths [1, 3.067(2) Å; 2, 2.994(3)
Å; 4, 3.033(4) Å] are as expected, given the scant literature
precedent, i.e., the terminal Ln-TeR bonds in [(py)2Ho-
(PhNNPh)(TePh)]2 [3.063(1) Å],32 Cp*2YbTePh(NH3) (3.039-
(30) Corrigan, J.; Fenske, D. Angew. Chem., Int. Ed. Engl. 1997, 36, 1981.
(31) Shannon, R. D. Acta Crystallogr., Sect. A 1976, 32, 751.
Inorganic Chemistry, Vol. 41, No. 3, 2002 497

Freedman et al.
iodide structural features can be explained by noting that
X- is donating electron density into the σ* orbital of the
XX, thus lengthening the XX bond. While bond lengths in
the TeTe units would lead to the conclusion that these
polytelluride ligands are best described as Te5Ph5- for 1 and
2 and Te9Ph9- for 4, there are alternative methods for
assessing or qualifying these nebulous interactions. In the
literature, there is a general consensus that distances less than
3.75 Å constitute a significant TeTe interaction.39-47 Given
this breakpoint, the multitellurium ligands in this work would
be described as Te5Ph5- (1), Te7Ph7- (2), and Te9Ph9- (4).
A comparison of the poly-Te ligands in 1-4 with the
recently described Te(Ph)Te(Ph)Te(Ph) would also be ap-
-
propriate.48 Oddly enough, this tritellurolate analogue of I3
Figure 3. ORTEP diagram of (py)7TmTe[(TeTe)4TePh](Te0.6TePh) with
the C and H atoms removed for clarity and with the thermal ellipsoids drawn
at the 50% probability level.
was also obtained in synthetic studies of lanthanide com-
pounds, but in this case, introduction of the sterically
demanding, highly electronegative ancillary pyrazolylborate
ligand completely excludes coordination of Te to the Ln to
produce an outer sphere (TePh)3- ion. In this unusual anion,
there are a pair of inequivalent Te-Te bonds [3.112(1) Å,
2.939(1) Å] that are considerably longer than the TeTe bond
in PhTeTePh [2.712(2) Å]49 and are distinctly similar to the
TeTe interactions noted in the present work.
Discrete molecular compounds with ditelluride ligands are
uncommon.50-53 Of the reported ditellurides, most are found
in combination with chalcophilic metals, and they exhibit a
wide range [i.e., 2.665(2) Å in (R3P)3Ni(TeTe),50 2.841(2)
Å in Mo4Te162- 51] of Te-Te bond lengths. There also exists
a limited, but rich, structural chemistry of solid-state materials
with extensive networks of weak TeTe interactions.52-60
Lanthanide complexes are scarce, but again, with highly
electronegative, sterically demanding ancillary ligands, com-
pounds with ditelluride linkages spanning a pair of Ln(III)
ions can be isolated, i.e., [(Cp*)2Ln]2(TeTe) (Ln ) Sm,5
(1) Å),6 Cp*2Sm(thf)(TeMes) [3.088(2) Å],7 and La(TeSiR3)3-
(DMPE)2 [av 3.155(5) Å].11,12 The Ln-N distances agree
with previously reported values for pyridine derivatives of
Ln(EPh)3.
The tellurium clusters reported here are also structurally
similar to the recently described selenium-rich clusters
(py)8Yb4Se(SeSe)3(SeSeSePh)(SePh) and (py)8Yb4Se(SeSe)3-
(SeSeTePh)(SeTePh) that also have an EPh ligand displaced
from a Yb(III) ion and coordinating to an EE moiety.20 The
major difference between the products described here and
the selenium-rich clusters is the extent that the displaced EPh
interacts with the EE units. Chemically, the tellurium-rich
clusters are also considerably more unstable.
Similarities with polyiodide chemistry are clearly evident
in the structures. From Figure 4, which shows a schematic
diagram of the Te5Ph5- ligands in 1, 2, and 4, it is clear that
the interaction of TePh with the TeTe diads depends
significantly on environment. In cluster 1, there is a modest
asymmetry to the interaction between PhTe and the two TeTe
units. A greater difference is noted in the Tb cluster 2, while
in 4, the bonding description becomes increasingly less clear.
Such a continuum33 of bonding interactions are often found
for the heavier halides, chalcogenides, pnictides, and latter
transition metals, with chalcogenido interactions being
described as complicated van der Waals interactions.33,34
In all three structures, coordination of PhTe to Te(9)-
Te(8) and Te(7)-Te(6) is clearly more significant, as judged
by the shorter PhTe-Te2 bonds and the considerable
lengthening of these Te-Te bonds, relative to the remaining
two ditelluride ligands. Essentially the same features are
(39) Jobic, S.; Deniard, P.; Brec, R.; Rouxel, J.; Jouanneaux, A.; Fitsch,
A. Z. Anorg. Allg. Chem. 1991, 598/599, 199.
(40) Monconduit, L.; Evain, M.; Boucher, F.; Brec, R.; Rouxel, J. Z. Anorg.
Allg. Chem. 1992, 616, 177.
(41) Canadell, E.; Monconduit, L.; Evain, M.; Brec, R.; Rouxel, J.;
Whangbo, M.-H. Inorg. Chem. 1993, 32, 10.
(42) Evain, M.; Monconduit, L.; van der Lee, A.; Brec, R.; Rouxel, J.;
Canadell, E. New J. Chem. 1994, 18, 215.
(43) van der Lee, A.; Evain, M.; Monconduit, L.; Brec, R.; Petricek, V.
Inorg. Chem. 1994, 33, 3032.
(44) Evain, M.; Monconduit, L.; Brec, R. J. Solid State Chem. 1995, 119,
394.
(45) Canadell, E.; Jobic, S.; Brec, R.; Rouxel, J.; Whangbo, M.-H. J. Solid
State Chem. 1992, 99, 189.
(46) Whangbo, M.-H.; Canadell, E. J. Am. Chem. Soc. 1992, 114, 9587.
(47) Canadell, E.; Mathey, Y.; Whangbo, M.-H. J. Am. Chem. Soc. 1988,
110, 104.
-
found in the numerous structures of I5 compounds,35-38
(48) Hillier, A. C.; Liu, S.; Sella, A.; Elsegood, M. R. J. Angew. Chem.,
Int. Ed. 1999, 38, 2745.
(49) Llabres, P. G.; Dideberg, O.; DuPont, L. Acta Crystallogr. 1972, B28,
2438.
where I2 units that bond more strongly to the I- also
consistently have the longer I-I bond. Both tellurido and
(50) DiVaira, M.; Peruzzini, M.; Stoppioni, A. Angew. Chem., Int. Ed. Engl.
1987, 26, 916.
(51) Eichhorn, B. W.; Haltshauer, R. C.; Cotton, F. A.; Wilson, B. Inorg.
Chem. 1988, 27, 4084.
(32) Kornienko, A.; Freedman, D.; Emge, T. J.; Brennan, J. G. Inorg. Chem.
2001, 40, 140.
(33) Pyykko¨, P. Chem. ReV. 1997, 97, 597.
(34) Klinkhammer, K. W.; Pyykko, P. Inorg. Chem. 1995, 34, 4134.
(35) Blake, A.; Lippolis, V.; Schroder, M. Chem. Commun. 1996, 2207.
(36) Ercolani, C.; Pennesi, G.; Trigiante, G. Inorg. Chem. 1995, 34, 2535.
(37) Hills, A.; Hughes, D. L.; Leigh, G. J.; Sanders, J. R. J. Chem. Soc.,
Dalton Trans. 1991, 61.
(38) Beno, M.; Geiser, U.; Kostka, K.; Wang, H.; Webb, K.; Firestone,
M.; Carlson, K.; Nunez, L.; Whangbo, M.; Williams, J. Inorg. Chem.
1987, 26, 1912.
(52) Sroof, L.; Pennington, W.; Krolis, J. Inorg. Chem. 1992, 31, 2056.
(53) Fenske, D.; Steck, J.-C.; Angew. Chem., Int. Ed. Engl. 1993, 32, 238.
(54) Stauf, S.; Reisner, C.; Tremel, W. Chem. Commun. 1996, 1749.
(55) Ibers, J. A.; Bollinger, J. C.; Roof, L. C. Inorg. Chem. 1995, 34, 1430.
(56) Smith, D. M.; Roof, L. C.; Ibers, J. A. Inorg. Chem. 1996, 35, 4999.
(57) Dhingra, S. S.; Haushalter, R. C. Inorg. Chem. 1994, 33, 2735.
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5050.
498 Inorganic Chemistry, Vol. 41, No. 3, 2002

Chalcogen-Rich Lanthanide Clusters
Figure 4. Bond length variations in the “TeTeTe(Ph)TeTe” ligands in 1 (Sm) and 2 (Tb), the two most significant PhTe-(TeTe) interactions in 4 (Tm),
-
and variations in typical symmetric and asymmetric I5 ligands.
Still, magnetic susceptibility measurements of both com-
pounds clearly revealed a complete absence of significant
interactions between neighboring Ln(III) spin systems. Plots
of 1/ø vs T showed ideal Curie Weiss behavior at all
temperatures. Magnetic moments for both 3 (10.6 µB) and 4
(7.60 µB) were found to be surprisingly close to the values
for the respective Ln2O3 (Ln ) Ho, µ ) 10.6 µB;61 Ln )
Tm, µ ) 7.56 µB62), given the extreme sensitivity of the
compounds, particularly to light and heat. Of the solid-state
telluride compounds available for comparison, only the
magnetic properties of Tm2Te3 (µ ) 7.56 µB; Tp ) -6 K,
ideal Curie-Weiss behavior > 10 K)63 have been reported,
and again, the properties are essentially indistinguishable
Figure 5. The temperature-dependent magnetic susceptibility (ø) and its
inverse (ø-1) for (py)8HoTe(TeTe)2(TeTeTe(Ph)TeTe)(Te0.1TePh).
from those of 4.
In the electronic spectra, there are no well-defined absorp-
tion maxima for 2-4. Given the multitude of allowed
transitions associated with the different Te-Te bonds, the
vibrational broadening associated with the PhTe ligand, and
the four different Te to Ln CT excitations that tail into the
visible spectrum, a featureless spectrum was unfortunately
both anticipated and observed. This contrasts with the well-
resolved electronic spectrum of (THF)6Yb4(SS)4(S)I2, which
has a less complicated chalcogen array, a σ f σ* manifold
in the UV spectrum, and only LMCT absorptions shifted
clearly into the visible spectrum because of the relative
stability of the Yb(II) excited state.19
Figure 6. The temperature-dependent magnetic susceptibility (ø) and its
inverse (ø-1) for (py)7TmTe[(TeTe)4TePh](Te0.6TePh).
Thermolysis. Thermolyses of 2, 3, and 4, give the single-
phase products TbTe2-x, HoTe, and TmTe, respectively, with
elimination of Ph2Te and Te, thus adding to the already
Yb4). In these organometallic compounds, the TeTe bond
lengths are 2.773(1) Å (Sm) and 2.769(1) Å (Yb). There is
no precedence for either (Te5Ph)5- (Te7Ph),7- or (Te9Ph).9-
Measuring the magnetic and electronic properties of 3 and
4 was complicated by the extreme sensitivity of the samples.
(61) Pinaeva, M. M.; Krylov, E. I.; Ryakov, V. M. Inorg. Mater. USSR
1965, 1, 1428.
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1437.
Inorganic Chemistry, Vol. 41, No. 3, 2002 499

Freedman et al.
diverse reactivity patterns noted in Ln(ER)x thermolyses.64-68
Unusual Te-rich solid-state products might have been
anticipated, given the presence of excess Te in the starting
materials, but the tendency of Te-rich Ln phases to lose Te
by evaporation is clearly a significant factor in product
determination. The elimination of Ph2Te has considerable
literature precedent.69 Of the comparable lanthanide chalco-
genolate thermolyses in the literature, there are certain
similarities with the present work. While most Ln(ER)3 give
Ln2E3 (Ln ) La, Ce; E ) Te; Ln ) Yb, E ) Se; Ln ) Ho,
Tm, Yb, E ) S) (reaction 3), LnE (reaction 4) solid-state
phases have been noted with a readily reduced Eu(III)
precursor, and phase-separated (LnSe/LnSe2) products have
also been observed (reaction 5).
There are, unfortunately, no well-defined LnTex phase dia-
grams available in the literature that might help to explain
why the individual phases are observed.
Conclusion
Tellurido clusters of redox-inactive lanthanides are isolable
compounds that are oxygen-, water-, heat-, and light-sen-
sitive. The compounds are clearly trivalent, as judged by
magnetic susceptibility and X-ray diffraction experiments.
These materials are useful single source precursors to solid-
state LnTex. Significantly, because tellurolate ligands are so
readily displaced from Ln coordination spheres, lanthanide
compounds with tellurolate ligands can be useful for doping
Ln ions into Te rich matrixes.70
Acknowledgment. This work was supported by the
National Science Foundation under Grant No. CHE-9982625.
2Ln(EPh)3 f Ln2E3 + 3ER2
2Ln(EPh)3 f 2LnE + REER + 2ER2
2Ln(EPh)3 f LnE2 + LnE + 3ER2
(3)
(4)
(5)
Supporting Information Available: X-ray crystallographic files
in CIF format for the crystal structures of 1, 2, and 4 are available.
This material is available free of charge via the Internet at
http://pubs.acs.org.
IC010981W
Thermolysis of clusters 2-4 clearly resembles reaction
5 with the presence of excess Te accounting for the
observation of the Te-rich phase in 2 and subsequent Te
evaporation producing the metallic LnTe (NaCl phase) solids.
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500 Inorganic Chemistry, Vol. 41, No. 3, 2002