Silylchalcogenolates MESiRtBu2 (M = Na, Cu, Zn, Fe; e = S, Se, Te; R =tBu, Ph) and disilyldichalcogenides tBu2RSiE-ESiRtBu2 (E = S, Se, Te; R = tBu, Ph): Synthesis, pr

Article abstract of DOI:10.1021/ic048710j

The sodium silyl chalcogenolates NaESiR^tBu₂ (R = Ph, ^tBu; E = S, Se, Te), accessible by the nucleophilic degradation of S, Se, or Te by the sodium silanides NaSiR^tBu₂ (R = Ph, ^tBu), have be

Full text of DOI:10.1021/ic048710j

Inorg. Chem. 2005, 44, 3449−3458
Silylchalcogenolates MESiRtBu2 (M
)
Na, Cu, Zn, Fe; E
)
S, Se, Te; R
S, Se,
t
)
tBu, Ph) and Disilyldichalcogenides Bu2RSiE
−
ESiRtBu2 (E
)
Te; R
)
tBu, Ph): Synthesis, Properties, and Structures
Theresa I. Ku1ckmann, Melina Hermsen, Michael Bolte, Matthias Wagner, and Hans-Wolfram Lerner*
Institut fu¨r Anorganische Chemie, Johann Wolfgang GoethesUniVersita¨t Frankfurt am Main,
Marie-Curie-Strasse 11, 60439 Frankfurt am Main, Germany
Received September 15, 2004
t
The sodium silyl chalcogenolates NaESiRtBu2 (R
)
Ph, Bu; E
)
)
S, Se, Te), accessible by the nucleophilic
Ph, Bu), have been characterized by X-ray
degradation of S, Se, or Te by the sodium silanides NaSiRtBu2 (R
t
structure analysis. Protonolysis of the sodium silyl chalcogenolates yields the corresponding chalcogenols. The Cu
and Zn chalcogenolates, [Cu(SSiPhtBu2)]4 and [ZnCl(SSitBu3)(THF)]2, have been synthesized by metathesis reactions
of CuCl with NaSSiPhtBu2 and of ZnCl2 with NaSSitBu3, respectively. The solid-state structures of the transition
t
t
metal thiolates have been determined. The compounds Bu2RSiE
−
ESiRtBu2 (R
)
Ph, Bu; E
)
S, Se, Te) are
t
accessible via air oxidation. With the exception of Bu3SiS
−
SSitBu3, these compounds were analyzed using X-ray
crystallography and represent the first structurally characterized silylated heavy dichalcogenides. Oxidative addition
t
of Bu3SiTe
−
TeSitBu3 to Fe(CO)5 yields [Fe(TeSitBu3)(CO)3]2, which has also been structurally characterized.
Introduction
bulky siloxides can function as analogues for the ubiquitous
cyclopentadienyl (Cp) ligand.4 These sterically hindered
In a number of recent studies, bulky silyl chalcogenolate
ligands of the type R3SiE- (E ) O, S, Se, Te) have been
used to stabilize transition metal centers. Such ligands have
drawn interest for a number of reasons. The chalcogen donor
atoms are often found to bridge metal centers, suggesting
possible applications in the stabilization of transition metal
clusters.1 At the same time, the large organic substituents,
such as phenyl, tert-butyl, and trimethylsilyl, with or without
bulky ancillary ligands, control the nuclearity of the com-
pounds, sometimes even producing mononuclear complexes.2
The resulting low nuclearity and increased solubility make
such compounds easier to characterize and study. Investiga-
tions of the reactivity of the supersilyl group (tBu3Si-),
including preliminary studies of its reactivity with chalco-
gens, have been reported.3 It has also been suggested that
ligands enforce a nearly linear Si-O-M coordination angle,
allowing for π donation from the oxygen atom to the metal
center. This makes such siloxides formal five-electron donors,
whereas the large substituents lead to a cone angle that
approaches that of the Cp ring. Obviously, the heavier
chalcogens will behave differently than oxygen. They are
generally regarded as better electron donors, but their large
size makes the enforcement of linear coordination, which is
necessary for π donation, more difficult. Further investigation
is needed to better understand these effects.
Here, we present the synthesis and characterization of the
bulky silyl chalcogenolate ligands tBu2RSiE- (R ) Ph, tBu;
E ) S, Se, Te). These compounds display interesting redox
behavior, and initial investigations of their coordination
chemistry with first-row transition metals make them inter-
esting candidates for the development of low nuclearity,
potentially redox-active metal clusters. In addition, the
simultaneous investigation of the chalcogen elements in the
third through fifth periods gives us the opportunity to
compare their reactivity and to decipher trends in their
coordination behavior.
* Author to whom correspondence should be addressed. Fax: +49-
69798-29260. E-mail: lerner@chemie.uni-frankfurt.de.
(1) (a) Sydora, O. L.; Wolczanski, P. T.; Lobkovsky, E. B. Angew. Chem.
2003, 115, 2789. (b) Komuro, T.; Matsuo, T.; Kawaguchi, H.; Tatsumi,
K. J. Chem. Soc., Dalton Trans. 2004, 1618. (c) Komuro, T.;
Kawaguchi, H.; Tatsumi, K. Inorg. Chem. 2002, 41, 5083.
(2) (a) Gindelberger, D. E.; Arnold, J. Inorg. Chem. 1993, 32, 5813. (b)
Tran, D. T. T.; Corrigan, J. F. Organometallics 2000, 19, 5202. (c)
Chownacki, J.; Becker, B.; Konitz, A.; Potrzebowski, M. J.; Wojnows-
ki, W. J. Chem. Soc., Dalton Trans. 1999, 3063.
(3) Wiberg, N. Coord. Chem. ReV. 1997, 163, 217.
(4) Wolczanski, P. T. Polyhedron 1995, 14, 3335.
Inorganic Chemistry, Vol. 44, No. 10, 2005 3449
10.1021/ic048710j CCC: $30.25
Published on Web 04/07/2005
© 2005 American Chemical Society

Ku1ckmann et al.
tBu2RSiE-ESiRtBu2
+ O2
2NaESiRtBu2 - Na O 8
(2)
Results and Discussion
2
2
2a: E ) S, R ) Ph
2b: E ) Se, R ) Ph
2c: E ) Te, R ) Ph
Synthesis. Despite significant interest in alkyl and aryl
silyl chalcogenolates as ligands for transition metal centers,
no single method of their preparation has established itself
as the most advantageous. In some instances, the corre-
sponding chalcogenols have been deprotonated in situ by
acidic metal centers.1c,2a In others, disilyl chalcogenides have
been employed in substitution reactions with metal halides,
leading to the thermodynamically favorable release of Me3-
SiX and the coordination of an R3SiE ligand to the metal
center.2b In a different approach, lithium silylthiolates of the
type LiSSiRMe2 were prepared by cleavage of cyclotrisi-
lathiane (Me2SiS)3 with methyllithium or tert-butyllithium.1b
The applicability of these methods, however, is limited by
the availability of suitable precursors. The bulky organic
substituents of our target molecules, for instance, make the
synthesis of corresponding cylcosilathianes impractical, and
of the chalcogenols relevant to the targeted ligands, only tBu3-
SiSH is known.3 For these reasons, a more general synthetic
route was applied. This method, previously described by
Arnold and co-workers for a number of related compounds,5
involves the insertion of elemental chalcogen into the silyl-
alkali metal bond of precursor alkali silanides. In this case,
2d: E ) S, R ) tBu
2e: E ) Se, R ) tBu
2f: E ) Te, R ) tBu
Similar behavior has been observed for the hypersilyl species
(THF)2LiTeSi(SiMe3)3, which can be oxidized to dark green
(Me3Si)3SiTeTeSi(SiMe3)3.5a The disilyl disulfides, while
accessible via air oxidation, can also be synthesized by
reaction of the corresponding sodium silanides with S2Cl2
in THF, as depicted in eq 3.
2NaSiRtBu2 + S2Cl2 - 2NaCl8
tBu2RSiS-SSiRtBu2 R ) tBu, Ph (3)
Filtration and recrystallization from pentane yields the
product disulfides as pale yellow blocks.
The dichalcogenides are stable under atmospheric condi-
tions; the disulfides 2a and 2d and diselenides 2b and 2e
show no signs of decomposition after several weeks of
exposure to moist air. Ditelluride 2f is also stable under
atmospheric conditions. Only the less bulky ditelluride 2c
shows signs of hydrolysis from atmospheric water vapor.
Oxidation to the disilyldichalcogenides can, however, be
reversed by reduction with alkali metals. When 2f is exposed
to an excess of potassium metal at room temperature, the
dark blue color slowly disappears and only those NMR
signals corresponding to the silyl chalcogenolate anion are
observed (eq 4).
the sodium silanides NaSiRtBu2 (R ) Ph, Bu), accessible
by reduction of halosilane precursors, are converted to the
corresponding sodium silyl chalcogenolates, as shown in eq
1.
t
NaESiRtBu2
NaSiRtBu2 + E f
(1)
1a: E ) S, R ) Ph
1b: E ) Se, R ) Ph
1c: E ) Te, R ) Ph
tBu3SiTe-TeSitBu3 + 2K f 2KTeSitBu3
(4)
1d: E ) S, R ) tBu
1e: E ) Se, R ) tBu
1f: E ) Te, R ) tBu
When diselenide 2e in THF is subjected to cyclic volta-
mmetric investigations, an irreversible reduction peak is
observed at -1.37 V (vs ferrocene1+/0). This is comparable
to the reduction of PhSeSePh in acetonitrile, which occurs
at -0.85 V versus SCE6 (-1.23 V vs ferrocene1+/0).7 The
reduction of diphenyl diselenide, however, is a reversible,
one-electron process. The electrochemical irreversibility of
the reduction of 2e indicates that the Si-Se-Se-Si moiety
is less stable than the CPh-Se-Se-CPh unit. This observation
can be rationalized by considering the positive inductive
effects of the SitBu3 substituents, which can be expected to
increase the overall electron density in the Si-Se-Se-Si
unit, as compared to the negative inductive effects of the
phenyl substituents, which should decrease the overall charge
density of the CPh-Se-Se-CPh moiety.
When equimolar amounts of the reactants in THF are used,
the products are obtained cleanly with only minor impurities
as a result of silanide hydrolysis and oxidation. The product
solutions are clear and yellow or orange in donor solvents.
Slow solvent evaporation yields off-white crystals, which
are readily soluble in polar organic solvents, slightly soluble
in aromatic solvents, and sparingly soluble in hydrocarbons.
The sodium chalcogenolates 1a-1f are air-sensitive. Upon
standing under atmospheric conditions, they are oxidized to
t
the corresponding disilyldichalcogenides Bu2RSiE-ES-
t
iRtBu2 (R ) Ph, Bu; E ) S, Se, Te) (see eq 2). This
oxidation is accompanied by a color change to brick red for
the selenium species and to deep ink blue for the tellurium
species; the sulfur species are yellow. Filtration and recrys-
tallization from pentane yields the dichalcogenides in pure,
crystalline form. NMR spectroscopy also confirms the
symmetric structure of the compounds.
Under the same experimental conditions, no comparable
reduction wave was found for ditelluride 2f. This result
suggests that the reduction potential of 2f is significantly
more negative than that of 2e, making the ditelluride harder
to reduce but the corresponding tellurolate easier to oxidize.
Compounds 1a-1f are also sensitive to protonolysis.
When treated with an excess of trifluoroacetic acid in C6D6,
(5) (a) Bonasia, P. J.; Gindelberger, D. E.; Dabbousi, B. O.; Arnold, J. J.
Am. Chem. Soc. 1992, 114, 5209. (b) Bonasia, P. J.; Christou, V.;
Arnold, J. J. Am. Chem. Soc. 1993, 115, 6777.
(6) Sobkowiak, A.; Sawyer, D. T. Inorg. Chem. 1990, 29, 1248.
(7) Conelly, N. G.; Geiger, W. E. Chem. ReV. 1996, 96, 877-910.
3450 Inorganic Chemistry, Vol. 44, No. 10, 2005

Synthesis of MESiRtBu2 and tBu2RSIE-ESiRtBu2
the silyl chalcogenolates are converted into the corresponding
silyl chalcogenols tBu2RSiEH (R ) Ph, tBu; E ) S, Se, Te),
as shown in eq 5.
NaESiRtBu2 + CF3CO2H - CF CO Na8
tBu2RSiEH
3
2
3a: E ) S, R ) Ph
3b: E ) Se, R ) Ph
3c: E ) Te, R ) Ph
3d: E ) S, R ) tBu
3e: E ) Se, R ) tBu
3f: E ) Te, R ) tBu
(5)
1
This reaction occurs quantitatively, as determined by H
NMR spectroscopy, with the signals of the starting material
protons disappearing completely. The products are easily
identified by the characteristic upfield shift of the chalcogenol
protons. The tellurol signals are observed near -7.5 ppm;
the selenol and thiol signals are found near -2.5 and -0.5
ppm, respectively. The thiols 3a and 3d and selenols 3b and
3e are stable in C6D6 solution at room temperature for several
months. As shown in eq 6, tellurol 3f slowly oxidizes to
ditelluride 2f.
Figure 1. Solid-state structure of 1a. Thermal ellipsoids are drawn at the
50% probability level. Hydrogen atoms have been omitted for clarity.
+ 0.5O2
complex [Fe(TeSitBu3)(CO)3]2 is formed cleanly and quan-
titatively, as determined by NMR spectroscopy. Slow
evaporation of the solvent leads to the deposition of red plates
suitable for X-ray crystal structure analysis.
2tBu3SiTeH
Bu3SiTe-TeSitBu3
- H O 8 t
(6)
2
3f
2f
As expected, the silyl chalcogenolates proved to be suitable
ligands for transition metal complexes. Salt metathesis
reactions of the sodium silyl thiolates 1a and 1d with CuCl
and ZnCl2 in THF produced the transition metal silyl thiolates
[Cu(SSiPhtBu2)]4 (4) and [ZnCl(SSitBu3)(THF)]2 (5), respec-
tively. After changing the solvent to toluene and removing
byproduct salts by filtration, the complexes were obtained
in crystalline form. Both compounds 4 and 5 are air-sensitive.
Copper thiolate 4 crystallizes as colorless needles, whereas
the zinc thiolate 5 is deposited as colorless blocks.
1
NMR Spectra. When considering the H, 13C, and 29Si
NMR spectra of the chalcogenols, dichalcogenides, and
chalcogenolates, certain general trends can be observed. As
is to be expected upon the replacement of an alkyl group
with an aryl substituent, the signals of all nuclei are shifted
downfield in the Bu3Si- compounds as compared to the
t
corresponding compounds with tBu2PhSi- substituents. In
addition, the signals of the silicon atoms and the quaternary
carbon atoms of the tert-butyl groups are shifted downfield
as the chalcogen is changed from sulfur to selenium to
tellurium. This effect can be observed among the dichalco-
genides and chalcogenols, as well as among the chalcogeno-
lates. It is always more pronounced for the 29Si signals than
for the quaternary 13C signals, and the relative difference in
chemical shift is generally larger between sulfur and selenium
than it is between selenium and tellurium. The aromatic and
alkyl proton signals and the signals of the primary 13C atoms
also tend to be shifted downfield in compounds containing
the heavier chalcogens, but the change in chemical shift is
smaller, making such trends more difficult to discern. No
general trend can be applied to the relative shifts of any
nucleus when comparing an analogous chalcogenolate,
dichalcogenide, and chalcogenol (i.e., 1a, 2a, and 3a).
Among the six chalcogenols, 3a-3f, the signals of the
The oxidative addition of dichalcogenides to low-oxida-
tion-state metals has been established as a common synthetic
route,8 although it has not yet, to our knowledge, been applied
with disilyl dichalchogenides. When a 2:1 benzene solution
of Fe(CO)5 and 2f is irradiated with a commonplace
fluorescent lamp, a color change from the ink blue of the
ditelluride to a deep red is observed, and the dinuclear
(8) For example: (a) Dey, S.; Kumbahare, L. B.; Jain, V. K.; Schurr, T.;
Kaim, W.; Klein, A.; Belaj, F. Eur. J. Inorg. Chem. 2004, 4510. (b)
Liaw, W.-F.; Lee, J.-H.; Gau, H.-B.; Chen, C.-H.; Lee, G.-H. Inorg.
Chim. Acta 2001, 322, 99. (c) Liaw, W.-F.; Chiang, M.-H.; Liu, C.-
J.; Harn, P.-J. Inorg. Chem. 1993, 32, 1536. (d) Albano, V. G.; Monari,
M.; Orabona, I.; Panunzi, A.; Ruffo, F. J. Am. Chem. Soc. 2001, 123,
4352.
Inorganic Chemistry, Vol. 44, No. 10, 2005 3451

Ku1ckmann et al.
Figure 2. Solid-state structure of 1b. Thermal ellipsoids are drawn at the 50% probability level. Hydrogen atoms have been omitted for clarity.
Figure 4. Solid-state structure of 1f. Thermal ellipsoids are drawn at the
50% probability level. Hydrogen atoms have been omitted for clarity.
Figure 3. Solid-state structure of 1e. Thermal ellipsoids are drawn at the
50% probability level. Hydrogen atoms have been omitted for clarity.
P21/n; selected bond lengths and angles are in Table 1). In
contrast to the core of the homologous siloxide NaOSiPh-
tBu2,9 the central core of 1a possesses an almost regular
heterocubane structure. The corners of this cube are alter-
nately occupied by S and Na atoms [1a: S-Na-S (av) )
92.21(6)°, Na-S-Na (av) ) 87.71(6)°]. In NaSSiPhtBu2,
no significant variations of the S-Si bond lengths are
observed [1a: S-Si (av) ) 2.8046(17) Å]. The coordination
spheres of the alkali metals are completed by solvent
chalcogenolic protons, as mentioned above, display a pro-
nounced upfield shift.
X-ray Crystallographic Structures. The molecular struc-
tures of chalcogenolates 1a, 1b, 1e, 1f, 4, 5, and 6 and
dichalcogenides 2c and 2f are shown in Figures 1-9.
Selected bond lengths and angles are listed in the corre-
sponding figure captions and in Tables 1 and 2. Crystal data
and refinement details are given in Tables 3-5.
Figure 1 represents the molecular structure of the sodium
chalcogenolate [(THF)NaSSiPhtBu2]4 1a (monoclinic,
(9) Lerner, H.-W.; Scholz, S.; Bolte, M. Organometallics 2002, 21, 3827.
3452 Inorganic Chemistry, Vol. 44, No. 10, 2005

Synthesis of MESiRtBu2 and tBu2RSIE-ESiRtBu2
three positions for each selenium atom, each of which is
1
occupied to /3.
In the solid state, the dichalcogenides 2a (monoclinic, P21/
n), 2b (monoclinic, P21/c), 2c (monoclinic, P21/c), 2e (both
molecules), and 2f (orthorhombic, Pbca) all possess Si-E-
E-Si chains that are exactly trans. The corresponding
torsional angles of 180° are mandated by the crystallographic
inversion center located in the middle of each of the E-E
bonds. These silyl dichalcogenides display Si-E-E angles
smaller than 109° [2a, 108.08(3)°; 2b, 100.238(19)°; 2c,
98.22(2)°; 2e (av), 99.5(4)°; 2f, 103.03(3)°]. The S-S bond
[2.0932(9) Å] in 2a is somewhat longer than the typical bond
lengths for aryl- and alkyl-substituted disulfides RS-SR (the
mean S-S distance for aryl disulfides is 2.050 Å; the mean
for alkyl disulfides is 2.024 Å).17 The Se-Se and Te-Te
bonds in dichalcogenides 2b, 2c, 2e, and 2f, however, have
bond lengths similar to those found in the corresponding
alkyl- and aryl-substituted dichalcogenides (2b, 2.3666(5)
Å; 2e (av), 2.360(2) Å; 2c, 2.7243(3) Å; 2f, 2.7398(7) Å;
the mean Se-Se bond length for aryl diselenides is 2.347
Å, and for alkyl diselenides, it is 2.310; the mean Te-Te
bond length for alkyl ditellurides is 2.724 Å).17
Figure 5. Solid-state structure of 2c. Thermal ellipsoids are drawn at the
50% probability level. Hydrogen atoms have been omitted for clarity. The
structures of 2a and 2b are analogous to that of 2c.
molecules. Along with the three S atoms, each Na atom in
1a is also coordinated by one molecule of tetrahydrofuran.
In contrast to the tetrameric solid-state structures of the
t
unsolvated siloxides NaOSiRtBu2 (R ) Bu, Ph)9 and the
monosolvated thiolate (THF)NaSSiPhtBu2 1a, the central
frameworks of the disolvated sodium chalcogenolates
(THF)2NaESitBu3 (E ) O, Se, Te)9 and (THF)2NaSeSiPhtBu2
are dimeric, forming four-membered rings. This structural
Tetrameric copper silyl thiolate 4, shown in Figure 7,
crystallizes in the tetragonal I4h space group. The four copper
atoms form a planar square with the thiolate ligands bridging
pairs of adjacent copper atoms. The S-Cu-S angles, at
178.38(4)°, deviate slightly from linearity, whereas the Cu-S
bond lengths, which average 2.16 Å, are typical for bridging
thiolates. The Cu‚‚‚Cu distances are quite short [2.8612(7)
and 2.8613(7) Å], suggesting the possibility of bonding
interactions between the metal centers. Similar structural
motifs, including short M‚‚‚M distances, have been observed
for other silyl thiolate complexes of coinage metals.1bc,11 The
5a
motif is also observed for (THF)2LiTeSi(SiMe3)3 and for
several arylsodium thiolates.10 The molecular structures of
1b, 1e, and 1f are shown in Figures 2-4 (selected bond
lengths and angles are in Table 1). These sodium chalco-
genolates crystallize in the space group P21/n, and their unit
cells each contain two formula units. The sodium atoms in
1b, 1e, and 1f are each coordinated by two chalcogen atoms
and two tetrahydrofuran molecules in a distorted tetrahedral
fashion.
1b
t
1c
related complexes [Cu(SSiPh3)]4 and [Cu(SSiMe2 Bu)]4
The distances of 2.228(4) and 2.2364(6) Å in 1b and 1e
are of a characteristic length for Se-Si bonds (the mean
length of metal-bound Se-Si bonds is 2.283 Å).
both display the central Cu4S4 eight-membered ring, although
in these complexes, there are two shorter Cu‚‚‚Cu interactions
[2.852(1) Å and 2.8128(6) and 2.7413(7) Å, respectively]
and two longer ones [3.027(1) Å and 2.9680(9) and 2.9541-
(9) Å, respectively], rather than four contacts of the same
X-ray quality crystals of 2a-2c, 2e, and 2f were grown
from pentane. Because 2a and 2b are isomorphous to 2c and
2e is isomorphous to 2f, only the ditellurides are depicted
(Figures 5 and 6). Selected bond lengths and angles for all
of the structurally characterized dichalcogenides can be found
in Table 2. Diselenide 2e crystallizes in the trigonal space
group R3h with two independent molecules in the asymmetric
unit. In the first molecule, the selenium atoms are disordered
over two positions. The position of atom Se(1) is occupied
to 76%; atom Se(1)′ is occupied to 24%. The corresponding
atoms Se(1)#1 and Se(1)′#1 are generated by the crystal-
lographic inversion center located in the center of the Se-
Se bond. In the second molecule in the asymmetric unit, the
silicon atoms (which are again related by a crystallographic
inversion center) lie on a 3-fold rotational axis. This creates
(11) Wo¨rner, A.; Polborn, K.; Wiberg, N.; Lerner, H.-W. CCDC 254421.
Crystal data for [AgSSitBu3]4: C48H108Ag4Si4, orthorhombic, space
group Cmc21, a ) 24.720(11) Å, b ) 16.886(5) Å, c ) 15.128(12)
Å, R ) 90°, â ) 90°, γ ) 90°; for preparation, see ref 12.
(12) Wo¨rner, A. Ph.D. Thesis, University of Munich, Germany, 1998.
(13) (a) Englich, U.; Chadwick, S.; Ruhlandt-Senge, K. Inorg. Chem. 1998,
37, 283. (b) Chadwick, S.; Ruhlandt-Senge, K. Chem.sEur. J. 1993,
32, 1536. (c) Niemeyer, M.; Power, P. P. Inorg. Chem. 1996, 35, 7264.
(d) Rose, D. J.; Chang, D. Y.; Chen, Q.; Kettler, P. B.; Zubieta, J.
Inorg. Chem. 1995, 34, 3973. (e) Anjali, K. S.; Vittal, J. J. Main Group
Met. Chem. 2001, 24, 129. (f) Brianso, M. C.; Brianso, J. L.; Gaete,
W.; Ros, J.; Suner, C. J. Chem. Soc., Dalton Trans. 1981, 852.
(14) (a) Mathur, P.; Reddy, V. D.; Das, K.; Sinha, U. C. J. Organomet.
Chem. 1991, 409, 255. (b) Bachman, R. E.; Witmire, K. H. Organo-
metallics 1993, 12, 1988. (c) Shieh, M.; Chen, P.-F.; Tsai, Y.-C.; Shieh,
M.-H.; Peng, S.-M.; Lee, G.-H. Inorg. Chem. 1995, 34, 2251.
(15) Wiberg, N.; Amelunxen, K.; Lerner, H.-W.; Schuster, H.; No¨th, H.;
Krossing, I.; Schmidt-Ameluxen, M.; Seifert, T. J. Organomet. Chem.
1997, 524, 1.
(10) For example: (a) Knotter, D. M.; Janssen, M. D.; Grove, D. M.;
Smeets, W. J. J.; Horn, E.; Spek, A. L.; van Koten, B. Inorg. Chem.
1991, 30, 4361. (b) Olmstead, M. M.; Power, P. P.; Shoner, S. C. J.
Am. Chem. Soc. 1991, 113, 3379. (c) Bochmann, M.; Bwernbya, G.;
Grinter, R.; Lu, J.; Webb, K. J.; Williamson, W. J. Inorg. Chem. 1993,
32, 532. (d) Malik, M. A.; Motevalli, M.; Walsh, J. R.; O’Brian, P.;
Jones, A. C. J. Mater. Chem. 1995, 5, 731.
(16) Lerner, H.-W.; Scholz, S.; Bolte, M.; Wagner, M. Z. Anorg. Allg.
Chem. 2004, 630, 443. (b) Lerner, H.-W.; Scholz, S.; Bolte, M. Z.
Anorg. Allg. Chem. 2001, 627, 1638.
(17) (a) Cambridge Structural Database, Version 5.25 with three updates;
Cambridge University: Cambridge, England, July 2004. (b) Allen, F.
H. Acta Crystallogr., Sect. B 2002, B58, 380.
Inorganic Chemistry, Vol. 44, No. 10, 2005 3453

Ku1ckmann et al.
Figure 6. Solid-state structure of 2f. Thermal ellipsoids are drawn at the 50% probability level. Hydrogen atoms have been omitted for clarity. The
structure of 2e is analogous to that of 2f.
of the zinc atoms are distorted; the Cl-Zn-S angles [127.47-
(7)-130.04(7)°] are widened considerably, whereas the
S-Zn-S angles [88.18(6)-88.54(8)°] are quite small. The
Zn-ligand distances vary only slightly between the four zinc
atoms in the asymmetric unit, and all bond lengths are in
the expected ranges. Such dimeric structures for thiolato-
bridged zinc chloride complexes are unusual. However,
several homoleptic zinc aryl thiolates also feature Zn2S2 rings
in the solid state.13a-d The only structurally characterized
complexes featuring Zn2S2 rings with terminal chloro ligands
are anionic and display dichloro zinc moieties.13e,f
Iron carbonyl tellurolate 6 (monoclinic, C2/c), shown in
Figure 9 (selected bond lengths and angles are in the figure
caption), displays a butterfly geometry in the solid state. The
iron and tellurium atoms sit at the corners of a slightly
distorted tetrahedron. Each iron atom is coordinated by three
carbonyl ligands. The distorted octahedral coordination
spheres are completed by bonds to the two bridging tellu-
rolate ligands and an iron-iron bond. This structural motif
Figure 7. Solid-state structure of 4. Thermal ellipsoids are drawn at the
is found in other iron carbonyl tellurolates, although, to the
best of our knowledge, no other similar complex with a silyl
tellurolate exists.14 The iron-iron distances in these com-
plexes (2.605-2.657 Å) are in the same range as those in 6
[2.645(2) Å]. The Fe-Te distances, however, are somewhat
shorter [the average is 2.54 Å vs 2.607(2) Å in 6]. This
disparity, however, can be attributed to the differences
between the silyl substituent in 6 and the alkyl substituents
in the other complexes.
50% probability level. Hydrogen atoms have been omitted for clarity.
Selected bond lengths (Å) and angles (deg): S(1)-Si(1) ) 2.1727(14), Si-
(1)-C(31) ) 1.895(4), C-S (av) ) 2.1597(10), Cu‚‚‚Cu (av) ) 2.8613-
(7), Si-CtBu (av) ) 1.924(5), S(1)-Cu(1)-S(1)#1 ) 178.38(4), Cu(1)#2-
Cu(1)-Cu(1)#1 ) 89.984, Cu(1)-S(1)-Cu(1)#2 ) 82.97(4), Cu(1)-S(1)-
Si(1) ) 108.85(5), Cu(1)#2-S(1)-Si(1) ) 104.77. Symmetry transformations
used to generate equivalent atoms: #1) -y + 1/2, x + 1/2, -z + 3/2; #2 )
1
1
3
y - /2, -x + /2, -z + /2.
length, as seen in 4. The silver thiolate [AgSSitBu3]4,11 on
the other hand, also displays four equal M‚‚‚M distances
(3.08 Å).
Summary and Conclusion
The zinc silyl thiolate 5 (monoclinic, C2/c), shown in
Figure 8 (selected bond lengths and angles are in the figure
caption), crystallizes with one complete and two half
molecules in the asymmetric unit. The two half molecules
are both related to their second halves (which are found in
neighboring asymmetric units) via a 2-fold rotational axis.
The structure displays a dimer with a central Zn2S2 ring. The
tetrahedrally coordinated zinc atoms are bridged by the two
thiolato ligands. Terminal cis-chloro and cis-THF ligands
complete the coordination spheres. The coordination spheres
In summary, it has been shown that the sodium silyl
t
chalcogenolates NaESiRtBu2 (E ) S, Se, Te; R ) Ph, Bu)
can be prepared from precursor sodium silanides via chal-
cogen degradation. These chalcogenolates are sensitive to
oxidation and protonolysis, yielding dichalcogenides and
chalcogenols. The chalcogenolates and dichalcogenides have
been studied by X-ray crystallography; all compounds have
been characterized by proton and heteronucleus NMR
spectroscopy.
3454 Inorganic Chemistry, Vol. 44, No. 10, 2005

Synthesis of MESiRtBu2 and tBu2RSIE-ESiRtBu2
Figure 8. Solid-state structure of 5 (molecule a). Thermal ellipsoids are drawn at the 50% probability level. Hydrogen atoms have been omitted for clarity.
Selected bond lengths (Å) and angles (deg). Molecule a: Zn-S (av) ) 2.338(2), Zn-O (av) ) 2.071(4), Zn-Cl (av) ) 2.182(2), S-Si (av) ) 2.162(2),
Si-C (av) ) 1.935(6), O-Zn-Cl (av) ) 101.87(15), O-Zn-S (av) ) 101.88(15), S-Zn-S (av) ) 88.50(6), Zn-S-Zn (av) ) 88.17(6), Si-S-Zn (av)
) 126.35(8), Cl(1)-Zn(1)-S(2) ) 129.07(7), Cl(1)-Zn(1)-S(1) ) 130.04(7), Cl(2)-Zn(2)-S(1) ) 129.33, Cl(2)-Zn(2)-S(2) ) 127.47(7). Molecule b:
Zn-S (av) ) 2.336(2), Zn(3)-O(301) ) 2.058(5), Zn(3)-Cl(3) ) 2.184(2), S(3)-Si(3) ) 2.167(3), Si-C (av) ) 1.932(8), O(301)-Zn(3)-Cl(3) ) 101.65-
(18), O-Zn-S (av) ) 102.71(18), S(3)-Zn(3)-S(3)#1 ) 88.41(7), Zn(3)-S(3)-Zn(3)#1 ) 88.76(7), Si-S-Zn (av) ) 126.41(10), Cl(3)-Zn(3)-S(3) )
129.62(9), Cl(3)-Zn(3)-S(3)#1 ) 127.56(10). Molecule c: Zn-S (av) ) 2.342(2), Zn(4)-O(401) ) 2.057(5), Zn(4)-Cl(4) ) 2.187(2), S(4)-Si(4) )
2.167(3), Si-C (av) ) 1.929(7), O(401)-Zn(4)-Cl(4) ) 102.35(18), O-Zn-S (av) ) 101.8(2), S(4)-Zn(4)-S(4)#1 ) 88.54(8), Zn(4)-S(4)-Zn(4)#1 )
87.68(7), Si-S-Zn (av) ) 126.35(11), Cl(4)-Zn(4)-S(4) ) 128.35(9), Cl(4)-Zn(4)-S(4)#1 ) 129.19(9). Symmetry transformations used to generate
3
equivalent atoms: #1 ) -x + 2, y, -z + /2.
Figure 9. Solid-state structure of 6. Thermal ellipsoids are drawn at the 50% probability level. Hydrogen atoms have been omitted for clarity. Selected
bond lengths (Å) and angles (deg): Fe(1)-Fe(1)#1 ) 2.645(2), Fe-C (av) ) 1.784(9), C-O (av) ) 1.138(11), Fe-Te (av) ) 2.6074(11), Te(1)-Si(1) )
2.622(2), Si-C (av) ) 1.945(8), Te-Fe-Fe (av) ) 59.44(4), Fe(1)-Te(1)-Fe(1)#1 ) 61.11(4), Te(1)-Fe(1)-Te(1)# ) 177.04(3), Fe-Te-Si (av) )
1
125.33(5). Symmetry transformations used to generate equivalent atoms: #1 ) -x + 1, y, -z + /2.
15
16
under dry nitrogen. NaSitBu3 and NaSiPhtBu2 were prepared
according to published procedures. All other starting materials were
purchased from commercial sources and used without further
purification. NMR spectra were recorded on Bruker AM 250,
Bruker DPX 250, Bruker AMX 400, and Bruker Advance 400
spectrometers. The 29Si spectra were recorded using the INEPT
pulse sequence with empirically optimized parameters for polariza-
tion transfer from the tert-butyl substituents. Using Te(OH)6 in D2O
at 712 ppm as an external standard, we referenced the 125Te spectra
to Me2Te at 0 ppm. 77Se spectra were referenced to Me2Se at 0
ppm. IR spectra were recorded on a Perkin-Elmer 1650 FTIR
spectrophotometer. Elemental analyses were performed at the
microanalytical laboratories of the Universita¨t Frankfurt. Cyclic
The silyl chalcogenolates show promise as ligands for
potentially redox-active transition metal clusters. The com-
plexes [Cu(SSiPhtBu2)]4, [ZnCl(SSitBu3)(THF)]2, and [Fe-
(TeSitBu3)(CO)3]2 have been isolated and structurally char-
acterized.
Experimental
General Considerations. All experiments were carried out under
dry argon or nitrogen using standard Schlenk and glovebox
techniques. Alkane solvents were dried over sodium and freshly
distilled prior to use. THF and toluene were distilled from sodium/
benzophenone. C6D6 was dried over molecular sieves and stored
Inorganic Chemistry, Vol. 44, No. 10, 2005 3455

Ku1ckmann et al.
Table 1. Selected Bond Lengths [Å] and Angles [deg] for Chalcogenolates 1a, 1b, 1e, and 1f
1a
1b
1e
1f
Si-E
2.0846(17) (av)
2.7664(30) (av)
2.295(4) (av)
1.919(5) (av)
1.894(5) (av)
126.72(9) (av)
87.71(6) (av)
92.21(6) (av)
2.228(4)
2.2364(6)
2.4654(7)
E-Na
2.881(6) (av)
2.289(14) (av)
1.928(20) (av)
1.873(14) (av)
109.83(17) (av)
82.72(18)
2.8677(9) (av)
2.3092(18) (av)
1.952(2) (av)
3.0617(12) (av)
2.287(3) (av)
1.948(3) (av)
Na-O
Si-CtBu
Si-CPh
Si-E-Na
Na-E-Na
E-Na-E
114.76(2) (av)
83.01(2)
96.99(2)
114.26(3) (av)
80.80(3)
99.20(3)
97.28(18)
Table 2. Selected Bond Lengths [Å] and Angles [deg] for Dichalcogenides 2a-2c, 2e, and 2f
2a
2b
2c
2ea
2ea
2f
E-E
2.0932(9)
2.1675(6)
1.9120(18) (av)
1.8840(17) (av)
102.08(3)
180
2.3666(5)
2.3106(6)
1.919(2) (av)
1.884(2)
100.238(19)
180
2.7243(4)
2.5180(8)
1.923(3) (av)
1.884(3)
98.22(2)
180
2.332(19) (av)
2.414(7) (av)
1.926(20) (av)
2.388(10)
2.421(10)
1.908(19)
2.7398(7)
2.5517(12)
1.933(6) (av)
Si-E
Si-CtBu
Si-CPh
Si-E-E
Si-E-E-Si
99.93(40) (av)
180
99.1(3)
180
103.03(3)
180
a Two independent molecules in the asymmetric unit.
Table 3. Crystal Data and Structure Refinement Parameters for 1a, 1b, 1e, and 1f
1a
1b
1e
1f
empirical formula
color
shape
C72H124Na4O4S4Si4
colorless
block
C44H78Na2O4Se2Si2
colorless
block
C40H86Na2O4Se2Si2
colorless
block
C40H86Na2O4Se2Si2
colorless
block
fw
1386.27
931.14
891.17
988.45
cryst syst
space group
monoclinic
P21/c
monoclinic
P21/n
monoclinic
P21/n
monoclinic
P21/n
a, Å
b, Å
c, Å
21.3211(14)
14.6608(9)
29.3525(18)
90
90.022(5)
90
9174.8(10), 4
1.004
0.212
10.1564(17)
14.708(2)
17.355(2)
90
98.172(12)
90
2566.2(2), 2
1.205
1.540
8.9662(8)
15.6100(9)
17.4525(15)
90
90.224(7)
90
2442.7(3), 2
1.212
1.614
9.0926(6)
16.5792(13)
17.0318(11)
90
90.693(5)
90
2567.3(3), 2
1.279
1.232
R, deg
â, deg
γ, deg
vol (Å3), Z
density (calcd), mg/m3
abs coeff µ(Mo KR), mm-1
F(000)
3008
984
952
1024
cryst size, mm3
reflns collected
independent reflns
final R indices [I > 2σ(I)], R1, wR2
0.52 × 0.46 × 0.33
0.42 × 0.38 × 0.35
0.34 × 0.28 × 0.22
0.36 × 0.26 × 0.20
49 292
24 241
25 568
28 074
16315
0.0828, 0.2030
4531
0.1691, 0.3697
4610
0.0289, 0.0574
5006
0.0263, 0.0606
Table 4. Crystal Data and Structure Refinement Parameters for 2a, 2b, 2c, 2e, and 2f
2a
2b
2c
2e
2f
empirical formula
color
C28H46S2Si2
yellow
C28H46Se2Si2
red
C28H46Te2Si2
blue
C24H54Se2Si2
red
C24H54Te2Si2
blue
shape
block
block
block
block
block
fw
cryst syst
space group
a, Å
b, Å
c, Å
502.95
monoclinic
P21/n
8.7385(9)
14.8594(18)
11.8876(12)
90
108.113(8)
90
596.75
monoclinic
P21/c
8.2842(7)
14.9971(11)
12.4940(11)
90
105.242(7)
90
694.03
monoclinic
P21/c
8.2602(7)
15.3176(9)
12.8106(10)
90
106.888(7)
90
556.77
trigonal
R3h
20.188(2)
20.188(2)
25.220(3)
90
90
120
8901.5(16), 12
1.264
2.582
654.05
orthorhombic
Pbca
14.6569(16)
13.5911(17)
15.1033(16)
90
R, deg
â, deg
90
90
γ, deg
vol (Å3), Z
1467.1(3), 2
1.139
0.277
1497.6(2), 2
1.323
2.563
1561.1(2), 2
1.476
1.959
3008.6(6), 4
1.444
2.027
density (calcd), mg/m3
abs coeff µ(Mo KR), mm-1
F(000)
548
620
692
3528
1320
cryst size, mm3
reflns collected
independent reflns
final R indices [I > 2σ(I)], R1, wR2
0.19 × 0.15 × 0.09
0.32 × 0.24 × 0.16
0.39 × 0.32 × 0.26
0.36 × 0.32 × 0.28
0.13 × 0.13 × 0.13
13 328
22 434
23 713
12 998
15 595
2879
0.0327, 0.0719
3083
0.0301, 0.0678
4415
0.0387, 0.1030
3537
0.1596, 0.3927
2675
0.0366, 0.0616
voltammetry was performed on a Princeton Applied Research
potentiostat in THF solution with [NBu4][PF6] as the electrolyte.
A platinum electrode was used with ferrocene as an internal
standard. Mass spectrometry [electrospray ionization (ESI)] was
performed with a Fisons VG Platform II instrument. UV-vis
absorption spectroscopy was carried out in cyclohexane using a
Varian Cary 50 Scan spectrophotometer and a Perkin-Elmer 555
spectrophotometer.
3456 Inorganic Chemistry, Vol. 44, No. 10, 2005

Synthesis of MESiRtBu2 and tBu2RSIE-ESiRtBu2
Table 5. Crystal Data and Structure Refinement Parameters for 4, 5, and 6
4
5
6
empirical formula
color
shape
C56H92Cu4S4Si4
colorless
needle
C32H70S2Cl2Zn2O2Si2
orange
block
C30H54Fe2O6Si2Te2
red
plate
fw
cryst syst
space group
a, Å
b, Å
c, Å
1260.06
tetragonal
I4h
20.106(2)
20.106(2)
7.7980(8)
90
808.82
monoclinic
C2/c
44.727(3)
17.3710(9)
21.8803(13)
90
101.404(5)
90
933.81
monoclinic
C2/c
15.975(2)
28.272(3)
11.2282(16)
90
131.151(9)
90
R, deg
â, deg
90
90
γ, deg
vol (Å3), Z
3152.4(5), 2
1.328
1.573
16664.3(17), 16
1.290
1.463
3818.5(8), 4
1.624
2.356
density (calcd), mg/m3
abs coeff µ(Mo KR), mm-1
F(000)
1328
6912
1864
cryst size, mm3
reflns collected
independent reflns
final R indices [I > 2σ(I)], R1, wR2
0.38 × 0.08 × 0.06
0.42 × 0.35 × 0.28
0.24 × 0.20 × 0.06
9708
10 4097
14 814
2988
0.0359, 0.0696
15 698
0.0631, 0.1664
3583
0.0498, 0.1287
Synthesis of Sodium Silyl Chalcogenolates 1a-1f. A Schlenk
flask is charged with 3 mmol of elemental chalcogen to which is
added a solution of an equimolar amount of silanide in THF (10
mL). After 16 h at room temperature, the product is obtained in
THF solution with ca. 5% impurity due to disilane, and the product
is used without further purification. Slow evaporation of the solvent
leads to the deposition of colorless crystals.
(THF)NaSSiPhtBu2 (1a). 1H NMR (C6D6): 8.251 (m, 2H,
m-Ph), 7.302 (m, 3H, o/p-Ph), 3.401 (m, 4H, THF OCH2), 1.291
(s, 18H, tBu2), 1.223 (m, 4H, THF CCH2) ppm. 13C NMR (C6D6):
141.9 (o-Ph), 136.8 (m-Ph), 127.0 (p-Ph), 68.0 (THF OCH2), 29.8
[C(CH3)3], 25.5 (THF CCH2), 19.0 (CMe3) ppm. 29Si NMR
(C6D6): 19.4 ppm.
1.187 (s, 27H, tBu3) ppm. 13C NMR (C6D6): 32.89 [C(CH3)3], 24.10
(CMe3) ppm. 29Si NMR (C6D6): 31.8 ppm.
Synthesis of Disilyldichalcogenides 2a-2f. Air oxidation of
THF solutions of the sodium silyl chalcogenolates yields the
corresponding disilyldichalogenides quantitatively, as determined
by NMR spectroscopy. These compounds can be freed of byproduct
salts by removal of the THF solvent, extraction with pentane, and
filtration.
Alternate Method for Preparation of Disulfides tBu3SiSSSitBu3
and tBu2PhSiSSSiPhtBu2. To a stirring solution of sodium silanide
(1.0 mmol) in 5 mL of THF is added 0.5 mmol of S2Cl2. After 1
h, the solvent is removed and the residue extracted with pentane.
Filtration and concentration of the filtrate yields the product as a
pale yellow solid.
1
(THF)2NaSeSiPhtBu2 (1b). H NMR (C6D6): 8.364 (m, 2H,
tBu2PhSiSSSiPhtBu2 (2a). Recrystallization from pentane at 4
m-Ph), 7.31 (m, 3H, o/p-Ph), 3.435 (m, 8H, THF OCH2), 1.350 (s,
t
27H, Bu2), 1.191 (m, 8H, THF CCH2) ppm. 13C NMR (C6D6):
°C yields the product as pale yellow blocks. 1H NMR (C6D6): 7.777
141.0 (o-Ph), 137.2 (m-Ph), 127.0 (p-Ph), 68.0 (THF OCH2), 30.2
[C(CH3)3], 25.5 (THF CCH2), 19.1 (CMe3) ppm. 29Si NMR
(C6D6): 25.9 ppm.
t
(m, 4H, m-Ph), 7.174 (m, 6H, o/p-Ph), 1.078 (s, 36H, Bu2) ppm.
13C NMR (C6D6): 135.7 (o-Ph), 129.6 (m-Ph), 129.1 (p-Ph), 28.8
[C(CH3)3], 21.6 (CMe3) ppm. 29Si NMR (C6D6): 23.1 ppm. MS
1
(THF)2NaTeSiPhtBu2 (1c). H NMR (C6D6): 8.470 (m, 2H,
(ESI) m/z: 251 (100%, Bu4Ph2Si2S22-). Elem Anal. Calcd for
t
m-Ph), 7.325 (m, 3H, o/p-Ph), 3.524 (m, 8H, THF OCH2), 1.442
(s, 18H, tBu2), 1.304 (m, 8H, THF CCH2) ppm. 13C NMR (C6D6):
139.9 (o-Ph), 138.2 (m-Ph), 127.1 (p-Ph), 68.1 (THF OCH2), 30.8
[C(CH3)3], 25.5 (THF CCH2), 22.0 (CMe3) ppm. 29Si NMR
(C6D6): 29.4 ppm. 125Te NMR (C6D6): -1457 ppm.
C28H46S2Si2: C, 66.86; H, 9.22%. Found: C, 64.66; H, 9.42%.
tBu2PhSiSeSeSiPhtBu2 (2b). Red blocks of the product can be
obtained by recrystallization from pentane. 1H NMR (C6D6): 8.081
t
(m, 4H, m-Ph), 7.232 (m, 6H, o/p-Ph), 1.277 (s, 36H, Bu2) ppm.
13C NMR (C6D6): 136.9 (o-Ph), 133.2 (m-Ph), 127.9 (p-Ph), 30.2
[C(CH3)3], 23.9 (CMe3) ppm. 29Si NMR (C6D6): 26.5 ppm. MS
1
(THF)2NaSSitBu3 (1d). H NMR (C6D6): 3.60 (m, 8H, THF
t
OCH2), 1.42 (m, 8H, THF CCH2), 1.359 (s, 27H, Bu3) ppm. 13C
(ESI) m/z: 299 (100%, Bu4Ph2Si2Se22-, correct isotope pattern),
t
163 (52%, tBuPhSi-). Elem Anal. Calcd for C28H46Se2Si2: C, 56.35;
NMR (C6D6): 68.0 (THF OCH2), 31.5 [C(CH3)3], 25.3 (THF
CCH2), 24.3 (CMe3) ppm. 29Si NMR (C6D6): 25.5 ppm.
H, 7.77%. Found: C, 56.10; H, 7.70%. UV-vis λmax: 424 nm.
1
(THF)2NaSeSitBu3 (1e). H NMR (C6D6): 3.61 (m, 8H, THF
tBu2PhSiTeTeSiPhtBu2 (2c). Recrystallization from pentane
t
OCH2), 1.42 (m, 8H, THF CCH2), 1.384 (s, 27H, Bu3) ppm. 13C
1
yields the product as dark blue blocks. H NMR (C6D6): 8.071
t
NMR (C6D6): 68.0 (THF OCH2), 31.7 [C(CH3)3], 25.5 (THF
CCH2), 24.2 (CMe3) ppm. 29Si NMR (C6D6): 33.2 ppm. 77Se NMR
(C6D6): 133.6 ppm.
(m, 4H, m-Ph), 7.227 (m, 6H, o/p-Ph), 1.273 (s, 36H, Bu2) ppm.
13C NMR (C6D6): 137.7 (o-Ph), 134.7 (m-Ph), 129.7 (p-Ph), 30.5
[C(CH3)3], 24.0 (CMe3) ppm. 29Si NMR (C6D6): 26.5 ppm. MS
(ESI) m/z: 349 (20%, tBu4Ph2Si2Te22-, correct isotope pattern), 269
(33%, PhtBuSiTe-), 235 (100%, PhtBu2SiO-), 163 (17%, tBuPhSi-).
1
(THF)2NaTeSitBu3 (1f). H NMR (C6D6): 3.58 (m, 8H, THF
t
OCH2), 1.436 (s, 27H, Bu3), 1.41 (m, 8H, THF CCH2) ppm. 13C
tBu3SiSSSitBu3 (2d). 1H NMR (C6D6): 1.314 (s, 54H, tBu3) ppm.
NMR (C6D6): 67.8 (THF OCH2), 32.2 [C(CH3)3], 25.4 (THF
CCH2), 24.0 (CMe3) ppm. 29Si NMR (C6D6): 33.7 ppm.
13C NMR (C6D6): 30.9 [C(CH3)3], 25.4 (CMe3) ppm. 29Si NMR
t
Synthesis of Potassium Silyl Tellurolate KTeSitBu3. Ditelluride
2f (20 mg, 0.03 mmol) and potassium metal (20 mg, 0.5 mmol)
are combined in THF (0.6 mL). After 24 h at room temperature,
the color has changed from blue to colorless. 1H NMR (THF-d8):
(C6D6): 25.1 ppm. MS (ESI) m/z: 351 (14%, Bu4Si2S2-), 263
(21%, tBu3SiS2-), 231 (100%, tBu6Si2S22-), 163 (48%). Elem Anal.
Calcd for C24H54S2Si2: C, 62.26; H, 11.76%. Found: C, 59.64; H,
11.63%.
Inorganic Chemistry, Vol. 44, No. 10, 2005 3457

Ku1ckmann et al.
tBu3SiSeSeSitBu3 (2e). The diselenide can be obtained as brick-
red blocks by recrystallization from pentane. 1H NMR (C6D6):
1.316 (s, 54H, tBu3) ppm. 13C NMR (C6D6): 31.0 [C(CH3)3], 26.3
(CMe3) ppm. 29Si NMR (C6D6): 30.7 ppm. 77Se NMR (C6D6):
the residue is extracted with toluene and filtered. Slow evaporation
of the solvent yields the product as crystalline colorless needles
(37 mg, 0.029 mmol, 37%). 1H NMR (C6D6): 8.095 (m, 2H, m-Ph),
t
7.229 (m, 3H, o/p-Ph), 1.337 (s, 18H, Bu2) ppm. 13C NMR
-82.3 (1J
) 136.12 Hz) ppm. MS (ESI) m/z: 279 (100%,
(C6D6): 137.8 (o-Ph), 129.3 (m-Ph), 127.9 (p-Ph), 30.2 [C(CH3)3],
23.0 (CMe3) ppm. 29Si NMR (C6D6): 23.1 ppm. Elem Anal. Calcd
for C56H92S4Si4Cu4: C, 53.38; H, 7.36%. Found: C, 53.31; H,
7.80%.
77SeSi
tBu6Si2Se22-, correct isotope pattern), 215 (80%, Si2Se2-). Elem
Anal. Calcd for C24H54Se2Si2: C, 51.77; H, 9.78%. Found: C,
47.44; H, 9.11%. UV-vis λmax: 418 nm.
tBu3SiTeTeSitBu3 (2f). Recrystallization from pentane results
[ZnCl(SSitBu3)(THF)]2 (5). A solution of NaSSitBu3 (1 mmol)
in 2.5 mL of THF is added dropwise to solid ZnCl2 (74 mg, 0.5
mmol). The orange solution is stirred overnight. After removal of
the solvent under reduced pressure, the residue is extracted with
toluene and filtered. Slow evaporation of the solvent yields the
product as colorless crystalline blocks (130 mg, 0.16 mmol, 64%).
1H NMR (C6D6): 3.745 (m, 8H, THF OCH2), 1.390 (s, 54H, tBu3),
1.343 (m, 8H, THF CCH2) ppm. 13C NMR (C6D6): 137.7 (o-Ph),
134.7 (m-Ph), 129.7 (p-Ph), 30.9 [C(CH3)3], 25.3 (CMe3) ppm. 29Si
NMR (C6D6): 34.0 ppm. Elem Anal. Calcd for C32H70O2S2Si2Cl2-
Zn2: C, 47.52; H, 8.72%. Found: C, 46.22; H, 8.81%.
1
in the deposition of large, ink-blue plates of ditelluride. H NMR
(C6D6): 1.308 (s, 54H, tBu3) ppm. 13C NMR (C6D6): 31.5
[C(CH3)3], 26.3 (CMe3) ppm. 29Si NMR (C6D6): 33.8 ppm. 125Te
1
125
NMR (C6D6): -624.2 ( J TeSi ) 343.45 Hz) ppm. MS (ESI) m/z:
407 (50%), 335 (100%, Bu6Si2OTe22-, correct isotope pattern).
t
Elem Anal. Calcd for C24H54Te2Si2: C, 44.07; H, 8.32%. Found:
C, 44.12; H, 8.34%. UV-vis λmax: 576, 292 nm.
Synthesis of Silyl Chalcogenols 3a-3f. The sodium silyl
chalcogenolates are treated with an excess of trifluoroacetic acid
in C6D6. Conversion is quantitative, as determined by NMR
spectroscopy.
[Fe(TeSitBu3)(CO)3]2 (6). Ditelluride 2f (17 mg, 0.025 mmol)
and Fe(CO)5 (10 mg, 0.05 mmol) are combined in C6D6. The blue
solution is irradiated with a fluorescent light bulb for 8 h. An
accompanying color change to red is observed. Conversion is
quantitative, as determined by NMR spectroscopy. Slow evaporation
tBu2PhSiSH (3a). 1H NMR (C6D6): 7.803 (m, 2H, m-Ph), 7.160
t
(m, 3H, o/p-Ph), 1.059 (s, 18H, Bu2), -0.221 (s, 1H, SH) ppm.
13C NMR (C6D6): 135.7 (o-Ph), 134.6 (m-Ph), 129.6 (p-Ph), 28.8
[C(CH3)3], 21.6 (CMe3) ppm. 29Si NMR (C6D6): 21.8 ppm.
tBu2PhSiSeH (3b). 1H NMR (C6D6): 7.834 (m, 2H, m-Ph), 7.140
1
of the solvent yields the product as blood-red plates. H NMR
(m, 3H, o/p-Ph), 1.095 (s, 18H, tBu2), -2.294 (s, 1H, SeH, 1J
(C6D6): 1.195 (s, 54H, tBu3) ppm. 13C NMR (C6D6): 31.5
[C(CH3)3], 26.6 (CMe3) ppm. 29Si NMR (C6D6): 45.1 ppm. 125Te
NMR (C6D6): -1280 ppm. IR (KBr pellet, CO- absorptions):
77SeH
) 53.4 Hz) ppm. 13C NMR (C6D6): 136.2 (o-Ph), 134.3 (m-Ph),
129.6 (p-Ph), 29.1 [C(CH3)3], 21.9 (CMe3) ppm. 29Si NMR
1
(C6D6): 28.3 ppm. 77Se NMR (C6D6): -413.8 ( J SeH ) 53.4 Hz)
2044.0 (vs), 2006.6 (vs), 1978.9 (s), 1963.0 (s), 1954.0 (s) cm-1
.
77
ppm.
X-ray Structure Determination. Data collections were per-
formed on a Stoe-IPDS-II two-circle diffractometer with graphite-
monochromated Mo KR radiation. The structures were solved with
direct methods18 and refined against F2 by full-matrix least-squares
calculations with SHELXL 97.19 Hydrogen atoms were placed on
ideal positions and refined with fixed isotropic displacement
parameters using a riding model.
tBu2PhSiTeH (3c). 1H NMR (C6D6): 7.90 (m, 2H, m-Ph), 7.142
(m, 3H, o/p-Ph), 1.126 (s, 18H, tBu2), -7.478 (s, 1H, TeH, 1J
125TeH
) 25 Hz) ppm. 13C NMR (C6D6): 137.0 (o-Ph), 134.1 (m-Ph), 129.6
(p-Ph), 29.5 [C(CH3)3], 22.2 (CMe3) ppm. 29Si NMR (C6D6): 34.4
125
1
125
ppm. Te NMR (C6D6): -862.7 ( J
) 25 Hz) ppm.
TeH
tBu3SiSH (3d). 1H NMR (C6D6): 1.097 (s, 27H, tBu3), -0.556
(s, 1H, SH) ppm. 13C NMR (C6D6): 30.3 [C(CH3)3], 23.7 (CMe3)
ppm. 29Si NMR (C6D6): 27.8 ppm.
Acknowledgment. We are grateful to the University of
Frankfurt for financial funding and Chemetall GmbH for a
gift of tert-butyllithium.
tBu3SiSeH (3e). 1H NMR (C6D6): 1.114 (s, 27H, tBu3), -2.677
(s, 1H, SeH, 1J
) 52.6 Hz) ppm. 13C NMR (C6D6): 30.5
77SeH
[C(CH3)3], 24.0 (CMe3) ppm. 29Si NMR (C6D6): 34.8 ppm. 77Se
Supporting Information Available: Table of X-ray parameters,
atomic coordinates, and thermal parameters and bond distances and
angles. This material is available free of charge via the Internet at
http://pubs.acs.org.
1
77
NMR (C6D6): -413.9 ( J
) 52.6 Hz) ppm.
SeH
tBu3SiTeH (3f). 1H NMR (C6D6): 1.118 (s, 27H, tBu3), -7.983
(s, 1H, TeH) ppm. 13C NMR (C6D6): 31.0 [C(CH3)3], 24.1 (CMe3)
ppm. 29Si NMR (C6D6): 42.4 ppm.
IC048710J
Complex Synthesis. [Cu(SSiPhtBu2)]4 (4). A solution of NaS-
SiPhtBu2 (0.32 mmol) in 1 mL of THF is added dropwise to solid
CuCl (40 mg, 0.32 mmol). The red-brown solution is stirred
overnight. After removal of the solvent under reduced pressure,
(18) Sheldrick, G. M. Acta Crystallogr., Sect. A 1990, 46, 467.
(19) Sheldrick, G. M. SHELXL 97; University of Go¨ttingen: Go¨ttingen,
Germany, 1997.
3458 Inorganic Chemistry, Vol. 44, No. 10, 2005