Synthetic applications of (Me3SiNSN)2E (E = S, Se) in chalcogen-nitrogen chemistry: Formation and structural characterization of CI2TeESN2 (E = S, Se) and [PPh4] 2[Pd2(μ-Se2

Article abstract of DOI:10.1021/ic050261f

The reaction of (Me₃SiNSN)₂S with TeCl₄ in CH₂Cl₂ affords Cl₂TeS₂N₂ (1) and that of (Me₃SiNSN)₂Se with TeCl₄ produces Cl₂Te

Full text of DOI:10.1021/ic050261f

Inorg. Chem. 2005, 44, 4992−5000
Synthetic Applications of (Me3SiNSN)2E (E
Chalcogen-Nitrogen Chemistry: Formation and Structural
Characterization of Cl2TeESN2 (E S, Se) and [PPh4]2[Pd2(
(X Cl, Br)
) S, Se) in
)
µ-Se2N2S)X4]
)
Jari Konu,† Markku Ahlgre´n,‡ Stephen M. Aucott,¶ Tristram Chivers,*,§ Sophie H. Dale,¶
Mark R. J. Elsegood,¶ Kathryn E. Holmes,¶ Sarah L. M. James,¶ Paul F. Kelly,*,¶ and
Risto S. Laitinen*,†
Departments of Chemistry, UniVersity of Oulu, P.O. Box 3000, 90014 UniVersity of Oulu, Finland,
UniVersity of Calgary, 2500 UniVersity DriVe N.W., Calgary, Alberta, Canada T2N 1N4,
UniVersity of Joensuu, P.O. Box 111, 80101 Joensuu, Finland, and UniVersity of Loughborough,
Loughborough, LE11 3TU, United Kingdom
Received February 19, 2005
The reaction of (Me3SiNSN)2S with TeCl4 in CH2Cl2 affords Cl2TeS2N2 (1) and that of (Me3SiNSN)2Se with TeCl4
produces Cl2TeSeSN2 (2) in good yields. The products were characterized by X-ray crystallography, as well as by
NMR and vibrational spectroscopy and EI mass spectrometry. The Raman spectra were assigned by utilizing DFT
molecular orbital calculations. The pathway of the formation of five-membered Cl2TeESN2 rings by the reactions of
(Me3SiNSN)2E with TeCl4 (E
[PPh4]2[Pd2( -Se2N2S)X4] (X
)
)
S, Se) is discussed. The reaction of (Me3SiNSN)2Se with [PPh4]2[Pd2X6] yields
-
µ
Cl, 4a; Br, 4b), the first examples of complexes of the (Se2N2S)2 ligand. In both
cases, this ligand bridges the two palladium centers through the selenium atoms.
Introduction
X6Te2SeN2 (X ) Cl, Br).11 Haas et al.12-14 have shown that
the treatment of (OSN)2E (E ) S, Se) with TeCl4 leads to
novel tellurium-containing chalcogen-nitrogen compounds.
(Me3SiNSN)2S can be prepared from (Me3SiN)2S with
SCl2 and has been used as a starting material for the synthesis
of S4N4.15 We have recently reported that the analogous
reaction utilizing (Me3SiN)2S with SeCl2 leads to the
formation of (Me3SiNSN)2Se.16 While its reaction with SeCl2
produces 1,5-Se2S2N4, that with SCl2 affords an equimolar
mixture of S4N4 and 1,5-Se2S2N4. Interestingly, the reaction
of (Me3SiNSN)2S and SeCl2 also yields a similar equimolar
While the structural features and chemical properties of a
large number of sulfur-nitrogen compounds are well-
understood,1-4 selenium-nitrogen and tellurium-nitrogen
chemistry has seen rapid development only during recent
years. Reagents such as trimethylsilyl chalcogen diamides,
[(Me3Si)2N]2E (E ) S, Se), have provided routes for selenium
and tellurium-containing chalcogen-nitrogen compounds, for
example, 1,5-Se2S2N4,5 Se4N4,6 [(Se2SN2)Cl]2,7,8 X2TeSeSN2
(X ) Cl, Br, I),9 X2TeS2N2 (X ) Cl, Br),9 Cl2Te2SN2,10 and
* Authors to whom correspondence should be addressed. E-mail:
chivers@ucalgary.ca (T.C.); p.f.kelly@lboro.ac.uk (P.F.K.); risto.laitinen@
oulu.fi (R.S.L.).
(7) Wolmersha¨user, G.; Brulet, C. R.; Street, G. B. Inorg. Chem. 1978,
17, 3586.
(8) Maaninen, A.; Konu, J.; Laitinen, R. S.; Chivers, T.; Schatte, G.;
Pietika¨inen, J.; Ahlgren, M. Inorg. Chem. 2001, 40, 3539.
(9) Haas, A.; Pryka, M.; Scha¨fers, M. Chem. Ber. 1994, 127, 1865.
(10) Haas, A.; Kasprowski, J.; Pryka, M. J. Chem. Soc., Chem. Commun.
1992, 1144.
(11) Haas, A.; Scha¨fers, M. Chem. Ber. 1995, 128, 437.
(12) Haas, A.; Kasprowski, J.; Pryka, M. Chem. Ber. 1992, 125, 789.
(13) Haas, A.; Pryka, M. Chem. Ber. 1995, 128, 11.
(14) Haas, A.; Kasprowski, J.; Pryka, M. Chem. Ber. 1992, 125, 1537.
(15) Lidy, W.; Sundermeyer, W.; Verbeek, W. Z. Anorg. Allg. Chem. 1974,
406, 228.
† University of Oulu.
‡ University of Joensuu.
§ University of Calgary.
¶ University of Loughborough.
(1) Chivers, T. Chem. ReV. 1985, 85, 341.
(2) Chivers, T. In The Chemistry of Inorganic Homo- and Heterocycles;
Haiduc, I., Sowerby, D. B., Eds.; Academic Press: London, 1987;
Vol. 2, p 793.
(3) Oakley, R. T. Prog. Inorg. Chem. 1988, 36, 299.
(4) Wentrup, C.; Kampouris, P. Chem. ReV. 1991, 91, 363.
(5) Maaninen, A.; Laitinen, R. S.; Chivers, T.; Pakkanen, T. A. Inorg.
Chem. 1999, 38, 3450.
(16) Konu, J.; Maaninen, A.; Paananen, K.; Ingman, P.; Laitinen, R. S.;
Chivers, T.; Valkonen, J. Inorg. Chem. 2002, 41, 1430.
(6) Siivari, J.; Chivers, T.; Laitinen, R. S. Inorg. Chem. 1993, 32, 1519.
4992 Inorganic Chemistry, Vol. 44, No. 14, 2005
10.1021/ic050261f CCC: $30.25
© 2005 American Chemical Society
Published on Web 06/04/2005

Applications of (Me3SiNSN)2E in Chalcogen-Nitrogen Chemistry
Scheme 1
formation in the reaction of (Me3SiNSN)2S with salts of
[Pd2X6]2- (X ) Cl, Br) (Scheme 1b)23 raises the obvious
question as to the reactivity of (Me3SiNSN)2Se toward these
halobridged palladium species. Here, we report on such
reactions and show complexes of the new mixed anion
[Se2SN2]2- that is the first example of a selenium-substituted
five-membered chalcogen-nitrogen anion. X-ray crystal-
lography confirms the nature of this new ligand and reveals
it to coordinate to the palladium atoms via the two bridging
selenium atoms.
mixture. These reactions presumably proceed via cyclic four-
membered intermediates.16 The reactions of chalcogen di-
imides or diamides with tellurium halides provide obvious
routes to many chalcogen-nitrogen species. In This Paper,
we report the formation of Cl2TeS2N2 (1) together with small
amounts of S4N4‚TeCl4 (3)17 by the reaction of (Me3-
SiNSN)2S with TeCl4. Similarly, the reaction of (Me3-
SiNSN)2Se with TeCl4 affords Cl2TeSeSN2 (2) as the main
product.
Experimental Section
General Procedures. All reactions and manipulations of air-
and moisture-sensitive reagents were carried out under an argon
atmosphere passed through P4O10. SCl2, SO2Cl2, and TeCl4
(Aldrich) were used without further purification. [(Me3Si)2N]2S was
prepared from (Me3Si)2NH by utilizing the method of Wolmers-
ha¨user et al.7 and was purified by distillation. (Me3SiNSN)2S and
(Me3SiNSN)2Se were prepared from [(Me3Si)2N]2S by the proce-
dures described earlier.15,16,23 The salts [PPh4]2[Pd2X6] (X ) Cl or
Br) were prepared as reported previously.26 Hexane and THF were
dried by distillation over Na/benzophenone and dichloromethane
over P4O10 under a nitrogen atmosphere prior to use.
The above considerations concerning metal-free heavy
chalcogen-nitrogen systems also generally apply to metal
complexes of heavy chalcogen-nitrogen anions. Thus, the
first examples of complexes of Se-N anions were only
isolated many decades after the first metal sulfur-nitrogen
complexes. Since then, however, several examples of systems
containing combinations of chalcogens have been reported.
In general, all such complexes are based on one fundamental
unit, namely, a five-membered metallacycle containing the
[S3N]- or [S2N2]2- ligands (or the protonated analogue of
the latter, i.e., [S2N2H]-). Complexes of [Se3N]-,18 [Se2N2]2-,19
[SeSN2]2-,20 and [TeSN2]2-21 together with the protonated
forms of the latter three are all known (Scheme 1a).
Synthons used in the preparation of these species are
limited in number and include the binary Se4N4,18,19 which
is difficult to handle because of its shock sensitivity. Indeed,
in some cases the anions are actually generated in situ during
reactions in liquid ammonia.19 This lack of potential reagents
is one of the reasons for the slow development of complexes
containing heavy chalcogen analogues of larger S-N binary
ligand systems such as [S2N3]- 22,23 and [S4N4]2-.24,25 One
source of the former species is S5N6,22 for which there is no
selenated analogue, and the reactions of Se4N4 invariably
appear to result in the four-membered anions rather than the
putative [Se4N4]2- ligand.18,19 The most pertinent of the larger
sulfur-nitrogen ligands to this study is [S3N2]2-, which can
act as a bridging ligand between metal centers.23,26 Its
Spectroscopy. The 13C, 14N, 77Se, and 125Te NMR spectra of
the reaction solutions of (Me3SiNSN)2E (E ) S, Se) with E′Cl4
(E′ ) Se, Te) were recorded in dichloromethane and in THF on a
Bruker DPX 400 spectrometer operating at 100.62, 28.909, 76.406,
1
and 126.240 MHz, respectively, and the H NMR spectra of the
reaction solutions of (Me3SiNSN)2Se with [PPh4]2[Pd2X6] (X )
Cl, Br) were recorded on a Bruker AC250 spectrometer. The
spectral widths were 30.30, 14.49, 99.01, and 95.24 kHz for 13C,
14N, 77Se, and 125Te, respectively, yielding the respective resolutions
of 0.62, 7.08, 1.51, and 1.45 Hz/data point. The pulse widths were
4.0 µs for 13C, 12.0 µs for 14N, 6.70 µs for 77Se, and 6.67 µs for
126Te, corresponding to nuclear tip angles of 33, 44, 46, and 30°,
respectively. The 13C accumulations contained ca. 200 transients,14N
accumulations ca. 25 000 transients, 77Se accumulations ca. 20 000
transients, and 125Te accumulations 9000-18 000 transients. All
spectra were recorded unlocked. The 13C NMR chemical shifts are
reported relative to (CH3)4Si and the 14N NMR chemical shifts
relative to CH3NO2. All 77Se NMR spectra are referenced externally
to a saturated solution of SeO2 in D2O and 125Te NMR spectra to
a saturated solution of H6TeO6. The 77Se chemical shifts are reported
relative to neat Me2Se [δ(Me2Se) ) δ(SeO2) + 1302.6] and 125Te
chemical shifts relative to Me2Te [δ(Me2Te) ) δ(H6TeO6) + 712].
MS-EI mass spectra of 1 and 2 were recorded by using a
Micromass Quattro II spectrometer at 70 eV of electron energy.
The Raman spectra of 1 and 2 were recorded from solid samples
at room temperature by using a Bruker IFS-66 spectrometer
equipped with an FRA-16 Raman unit and Nd:YAG laser (power
110 mW; 8-64 scans; spectral resolution (1 cm-1; Blackmann-
Harris four-term apodization, no white light correction; scattering
geometry 180°). IR spectra of 4a and 4b were recorded on a Perkin-
Elmer 2000 spectrometer.
(17) The full characterization of 3 will be published elsewhere.
(18) Jones, R.; Kelly, P. F.; Williams, D. J.; Woollins, J. D. J. Chem. Soc.,
Chem. Commun. 1989, 408.
(19) Kelly, P. F.; Parkin, I. P.; Slawin, A. M. Z.; Williams, D. J.; Woollins,
J. D. Angew. Chem., Int. Ed. Engl. 1989, 28, 1047.
(20) Kelly, P. F.; Parkin, I. P.; Sheppard, R. N.; Woollins, J. D. Heteroatom.
Chem. 1991, 2, 301.
(21) Kelly, P. F.; Slawin, A. M. Z.; Williams, D. J.; Woollins, J. D.
Polyhedron 1990, 9, 2659.
(22) Kelly, P. F.; Slawin, A. M. Z.; Williams, D. J.; Woollins, J. D. Angew.
Chem., Int. Ed. Engl. 1992, 31, 616.
(23) Kelly, P. F.; Slawin, A. M. Z.; Soriano-Rama, A. J. Chem. Soc., Dalton
Trans. 1996, 53.
(24) Edelmann, F.; Roesky, H. W.; Spang, C.; Noltemeyer, M.; Sheldrick,
G. M. Angew. Chem., Int. Ed. Engl. 1986, 25, 931.
(25) Kelly, P. F.; Sheppard, R. N.; Woollins, J. D. Polyhedron 1992, 11,
2605.
Reactions of (Me3SiNSN)2E (E ) S, Se) with TeCl4. (Me3-
SiNSN)2S (0.149 g, 0.50 mmol) or (Me3SiNSN)2Se (0.172 g, 0.5
mmol) was dissolved in dichloromethane (20 mL). In both reactions,
the resulting solution was added to a suspension of TeCl4 (0.135
g, 0.50 mmol) in dichloromethane (10 mL) at -80 °C. The reaction
(26) Ginn, V. C.; Kelly, P. F.; Slawin, A. M. Z.; Williams, D. J.; Woollins
J. D. J. Chem. Soc., Dalton Trans. 1992, 963.
Inorganic Chemistry, Vol. 44, No. 14, 2005 4993

Konu et al.
Table 1. Crystal Data and Structure Refinement for Cl2TeS2N2 (1), Cl2TeSeSN2 (2), [PPh4]2[Pd2(µ-Se2N2S)Cl4] (4a), and [PPh4]2[Pd2(µ-Se2N2S)Br4]
(4b)
1
2
4a
4b
empirical formula
fw, g/mol
crystal system
space group
a, Å
Cl2N2S2Te
290.64
monoclinic
C2/c
19.8796(7)
8.7884(3)
7.2922(3)
96.234(2)
1266.49(8)
8
Cl2N2SSeTe
337.54
orthorhombic
Pbca
8.352(2)
7.953(2)
19.853(4)
90.00
1318.7(5)
8
C48H40Cl4N2P2Pd2SSe2
1251.34
monoclinic
P21/c
9.6484(6)
34.684(2)
14.6209(9)
97.824(2)
4847.3(5)
4
C48H40Br4N2P2Pd2 SSe2
1429.18
monoclinic
P21/c
9.9248(4)
34.890(1)
14.6325(6)
97.255(2)
5026.3(3)
4
b, Å
c, Å
â, deg
V, Å3
Z
T, °C
F
-150(2)
-120(2)
-120(2)
-120(2)
calcd, g/cm3
3.049
3.400
1.715
1.889
µ (Mo KR), mm-1
crystal size
6.076
11.039
2.609
5.484
0.25 × 0.25 × 0.05
0.20 × 0.20 × 0.10
0.41 × 0.05 × 0.03
0.56 × 0.18 × 0.12
F(000)
1056
1200
2464
2752
θ range, deg
reflns collected
unique reflns
R1 [I > 2σ(I)]a
wR2 (all data)
GOF on F2
2.54-27.48
7018
1439
2.05-24.98
13311
1150
1.52-25.00
23365
8544
1.52-25.00
36596
8842
0.0235
0.0415
0.0347
0.0250
0.0573b
1.220
0.1260c
1.190
0.0737d
0.0555e
1.053
1.021
a R1 ) Σ||Fo| - |Fc||/Σ|Fo|, wR2 ) [Σw(Fo2 - Fc )2/ΣwFo ]1/2
.
b w ) [σ2(Fo ) + (0.0200P)2 + 4.0000P]-1
.
c w ) [σ2(Fo ) + (0.0597P)2 + 31.6007P]-1
.
2
4
2
2
2
2
2
2
d w ) [σ2(Fo ) + (0.0223P)2 + 8.6937P]-1
.
e w ) 1/[σ2(Fo ) + (0.0214P)2 + 6.6340P]-1, where P ) (Fo + 2Fc )/3.
mixtures were stirred overnight and were allowed to warm slowly
to room temperature. In both cases, a reddish solution and a red-
bown precipitate were obtained. The precipitates were identified
as Cl2TeS2N2 (1) (0.047 g, 32% on the basis of the initial amount
of tellurium) in the case of the reaction involving (Me3SiNSN)2S
and Cl2TeSeSN2 (2) (0.081 g, 48% on the basis of the initial amount
of tellurium) in the case of the reaction involving (Me3SiNSN)2Se.
Further crystallization from the remaining reaction solution (CH2-
Cl2) at room temperature afforded red-brown plates of Cl2TeS2N2
(1) from the former reaction and red plates of Cl2TeSeSN2 (2) from
the latter reaction. In addition, the former reaction also produced a
small amount of red crystals of S4N4‚TeCl4 (3).17 All products were
characterized by vibrational, NMR, and mass spectrometry as well
as by X-ray crystallography. Cl2TeS2N2 (1): NMR (THF, 25 °C,
δ): 14N -79, -121;27 125Te 2110. MS [EI m/z (Irel)]: 46(100) NS+,
78(15) NS2+, 92(30) N2S2+, 130(86) Te+, 144(11) NTe+, 165(52)
ClTe+, 176(55) NSTe+, 200(40) Cl2Te+, 211(32) NSClTe+, 222-
(34) N2S2Te+, 246(37) NSCl2Te+, 257(81) N2S2ClTe+, 292(23)
N2S2Cl2Te+. Cl2TeSeSN2 (2): NMR (THF, 25 °C, δ): 14N -79,
-108;27 77Se 1195; 125Te 1973. MS [EI m/z (Irel)]: 46(100) NS+,
80(49) Se+, 94(62) NSe+, 130(73) Te+, 140(11) N2SSe+, 144(10)
NTe+, 165(45) ClTe+, 176(42) NSTe+, 200(40) Cl2Te+, 208(19)
SeTe+, 222(52) NSeTe+, 246(24) NSCl2Te+, 257(47) NClSeTe+,
268(57) N2SeTe+, 292(24) NCl2SeTe+, 303(65) N2SClSeTe+,
338(14) N2SCl2SeTe+.
Reactions of (Me3SiNSN)2Se with [PPh4]2[Pd2X6] [X ) Cl
(4a), Br (4b)]. 4a. A solution of [PPh4]2[Pd2Cl6] (0.200 g, 0.18
mmol) in dry CH2Cl2 (60 mL) was treated with solid (Me3-
SiNSN)2Se (0.125 g, 0.36 mmol), added with vigorous stirring. The
resulting solution immediately started to darken in color from light
orange to dark red and a cloudiness developed within a minute of
the start of reaction. After 48 h stirring, the mixture consisted of a
dark brown precipitate within a dark red solution. After filtration
and reduction of the solution volume to ca. 20 mL in vacuo, ether
vapor diffusion over many days afforded dark orange crystals of
4a (0.106 g, 47% on the basis of Pd). 4a: IR (cm-1): Bands due
to [PPh4]+ plus 1054 (w), 872 (w), 856 (w), 846 (w), 634 (m), 326
(mw), 307 (m), 297 (m). Anal. Calcd. for C48H40Cl4N2P2Pd2SSe2:
C 40.7, H 1.7, N 2.0; found: C 40.1, H 2.3, N 1.8.
The preparation of 4b was performed in an identical manner to
that generating 4a. [PPh4]2[Pd2Br6] (0.200 g, 0.15 mmol) was treated
with (Me3SiNSN)2Se (0.100 g, 0.30 mmol). In this case, the dark
wine-red color of the reaction mixture lightened with time; after
48 h, small amounts of orange precipitate were observed. Crystal-
lization as before yielded dark orange crystals of 4b (0.124 g, 58%
on the basis of Pd). 4b: IR (cm-1): Bands due to [PPh4]+ plus
1028 (w), 858 (w), 847 (w), 834 (w), 596 (m), 363 (m), 221 (m),
209 (m). Anal. Calcd. for C48H40Br4N2P2Pd2SSe2: C 39.8, H 2.6,
N 1.7; found: C 40.3, H 2.8, N 2.0.
X-ray Crystallography. Crystal data for Cl2TeS2N2 (1), Cl2-
TeSeSN2 (2),30 [PPh4]2[Pd2(µ-Se2N2S)Cl4] (4a), and [PPh4]2[Pd2-
(µ-Se2N2S)Br4] (4b) are given in Table 1. Diffraction data were
collected with a Nonius Kappa CCD diffractometer for 1 and 2
and with a Bruker SMART AXS 1000 CCD diffractometer for 4a
and 4b using graphite-monochromated Mo KR radiation (λ )
0.71073 Å) in both cases. The data were corrected for Lorentz and
(27) In reaction 1, 14N NMR spectra of the THF solutions also showed
28
signals for S4N4 (δ ) -256 ppm) and NH4Cl (δ ) -361 ppm)29
in addition to the product resonances. The resonance due to S4N4 is
repeatedly observed already in the 14N NMR spectra of the reaction
solutions, but NH4Cl is detected only after prolonged standing of the
sample in THF in the NMR tube. It is probable that NH4Cl is formed
by the decomposition of the product because of moisture in the solvent
or because the solvent itself initiates decomposition. To verify this
interpretation, the reaction of (Me3SiNSN)2S with TeCl4 was carried
out in CS2, and the precipitate was dissolved in THF followed by the
recording of the 14N NMR spectrum. Also in this case, NH4Cl was
detected in the NMR spectrum upon standing. The 13C NMR spectra
of reaction solutions of reaction 1 in CH2Cl2 showed only one
resonance for Me3SiCl excluding the unlikely possibility of Me groups
being the proton source for the formation of NH4Cl. This indicates
that the proton source for the formation of NH4Cl is indeed either
THF or moisture in THF and that NH4Cl is the decomposition product
of Cl2TeESN2 rather than a byproduct of reaction 1.
(28) Chivers, T.; Oakley, R. T.; Scherer, O. J.; Wolmersha¨user, G. Inorg.
Chem. 1981, 20, 914.
(29) Gillespie, R. J.; Kent, J. P.; Sawyer, J. F. Inorg. Chem. 1990, 29,
1251.
(30) The crystal structure of 2 has been reported at room temperature by
Haas et al.12 We have redetermined the crystal structure of 2 to identify
the product obtained from reaction 2 and to be able to compare the
bond parameters of 1 and 2 at low temperatures. The general structural
features of 2 at low temperatures are similar to those at room
temperature12 (see Figure 3).
4994 Inorganic Chemistry, Vol. 44, No. 14, 2005

Applications of (Me3SiNSN)2E in Chalcogen-Nitrogen Chemistry
polarization effects, and an empirical absorption correction was
applied to the net intensities. The structures 1 and 2 were solved
by direct methods using SHELXS-9731 and were refined using
SHELXL-97.32 The structures 4a and 4b were solved and refined
by using programs Bruker SMART,33 SAINT,33 SHELXTL,34 and
local programs. The scattering factors for the neutral atoms were
those incorporated with the programs.
Computational Details. Ab initio MO calculations of Cl2TeESN2
(E ) S, Se) were carried out using the Stuttgart relativistic large
core effective core potential approximation (RLC ECP)35-37 by
augmenting the double-ú quality basis sets of the valence orbitals
by two polarization functions for all atoms. Fundamental vibrations
and the geometry optimization of 1 and 2 were calculated at the
DFT level of theory involving Becke’s three-parameter hybrid
functionals with the Perdew/Wang 91 correlation (B3PW91).38-44
The calculated wavenumbers were scaled by 0.993 to eliminate
the systematic errors.45 The calculations for geometry optimizations
and fundamental vibrations were also performed at the same level
of theory with DZVP46 basis set which takes into account all
electrons of the atoms. In both cases, an excellent correlation
between the calculated and observed wavenumbers was achieved.
Calculations were performed with the GAUSSIAN 03 (Rev. B.04)
program.47
The EI mass spectra of both the initial reaction precipitate
and the crystallized product from the decanted solutions
formed in the reactions of both (Me3SiNSN)2S and (Me3-
SiNSN)2Se with TeCl4 exhibited the molecular ions of 1 and
+
2 (Cl2TeS2N2 , and Cl2TeSeSN2+), respectively, as fragments
of highest mass. A reasonable fragmentation pattern was also
observed for both compounds. The fragments were unam-
biguously assigned by consideration of isotopic distributions.
The calculated isotopic distributions of the molecular ions
of 1 and 2 as well as their fragments agree well with the
observed isotopic distribution patterns. The fragmentation
patterns are consistent with those proposed by Haas et al.9,12
The 14N and 125Te NMR spectra of 1 and 2 were recorded
in THF. The 14N NMR spectrum of 1 shows four signals at
-79, -121, -256, and -361 ppm and that of 2 shows four
resonances at -79, -108, -256, and -361 ppm. In both
cases, the first two signals are assigned to the five-membered
Cl2TeESN2 (E ) S, Se) rings (-79 and -121 ppm for 1
and -79 and -108 ppm for 2) and the latter two resonances
are assigned to S4N4 (-256 ppm) and NH4Cl (-361 ppm).27
The 14N chemical shifts of 1 and 2 are reasonable for the
five-membered TeS2N2-rings containing a NdSdN frag-
ment.50 The 125Te spectrum of 1 shows a single resonance
at 2110 ppm and that of 2 exhibits a single resonance at
1973 ppm, These two resonances show expected relative
values, since the replacement of the selenium atom with a
more electronegative sulfur atom in the five-membered
equatorial ring can be considered to cause deshielding of
the adjacent tellurium atom. However, Haas et al.9 reported
Results and Discussions
Reactions of (Me3SiNSN)2E with TeCl4 (E ) S, Se).48,49
The reaction of (Me3SiNSN)2S with TeCl4 in CH2Cl2 affords
Cl2TeS2N2 (1) in ca. 32% yield. The reaction also produces
N2, Me3SiCl, and S4N4 (eq 1). Some S4N4 subsequently reacts
with TeCl4 yielding a small amount of S4N4‚TeCl4 (3).17
a
125Te chemical shift of 1764 ppm for 1 recorded in THF/
(Me3SiNSN)2E + TeCl4 f
C6D6 (1:1). The 77Se NMR spectrum of 2 exhibits a single
resonance at 1195 ppm.
Cl2TeESN2 + 2Me3SiCl + 1/2N2 + 1/4S4N4 (1)
The Raman spectra of crystalline 1 and 2 are shown in
Figure 1.51 The assignment of the observed fundamental
vibrations of Cl2TeS2N2 (1) is based on the B3PW91
In an analogous manner, (Me3SiNSN)2Se reacts with TeCl4
producing Cl2TeSeSN2 (2) in ca. 48% yield (eq 1). In this
reaction, we did not observe the formation of S4N4‚TeCl4
(3).
(47) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb,
M. A.; Cheeseman, J. R.; Montgomery, J. A., Jr.; Vreven, T.; Kudin,
K. N.; Burant, J. C.; Millam, J. M.; Iyengar, S. S.; Tomasi, J.; Barone,
V.; Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.; Petersson, G.
A.; Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.;
Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai,
H.; Klene, M.; Li, X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.;
Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev,
O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P.
Y.; Morokuma, K.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.;
Zakrzewski, V. G.; Dapprich, S.; Daniels, A. D.; Strain, M. C.; Farkas,
O.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J.
B.; Ortiz, J. V.; Cui, Q.; Baboul, A. G.; Clifford, S.; Cioslowski, J.;
Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.;
Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.;
Nanayakkara, A.; Challacombe, M., Gill; P. M. W.; Johnson, B.; Chen,
W.; Wong, M. W.; Gonzalez, C.; Pople, J. A. GAUSSIAN 03, Revision
B.04; Gaussian, Inc.: Pittsburgh, PA, 2003.
(31) Sheldrick, G. M. SHELXS-97, Program for Crystal Structure Deter-
mination; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
(32) Sheldrick, G. M. SHELXL-97, Program for Crystal Structure Refine-
ment; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
(33) SMART and SAINT software for CCD diffractometers; Bruker AXS,
Inc.: Madison, WI, 1994.
(34) Sheldrick, G. M. SHELXTL, User Manual, Version 5; Bruker AXS,
Inc.: Madison, WI, 1994.
(35) Kuechle, W.; Dolg, M.; Stoll, H.; Preuss, H. Mol. Phys. 1991, 74,
1245.
(36) Bergner, A.; Dolg, M.; Kuechle, W.; Stoll, H.; Preuss, H. Mol. Phys.
1993, 80, 1431.
(37) Buhl, M.; Thiel, W.; Fleischer, U.; Kutzelnigg, W. J. Phys. Chem.
1995, 99, 4000.
(38) Becke, A. D. J. Phys. Chem. 1993, 98, 5648.
(39) Burke, K.; Perdew, J. P.; Wang, Y. In Electron Density Functional
Theory: Recent Progress and New Directions; Dobson, J. F., Vignale,
G., Das, M. P., Eds.; Plenum: New York, 1998.
(40) Perdew, J. P. In Electronic Structure of Solids; Ziesche, P., Eschrig,
H., Eds.; Akademie Verlag: Berlin, 1991.
(48) Haas et al.9 have reported that the reaction of [(Me3Si)2N]2S with TeCl4
and SCl2 in CH2Cl2 also produces Cl2TeS2N2. Although the charac-
terization of their product was incomplete, we believe that this reaction
indeed affords 1.
(41) Perdew, J. P.; Wang, Y. Phys. ReV. 1992, B45, 13244.
(42) Perdew, J. P.; Chevary, J. A.; Vosko, S. H.; Jackson, K. A.; Pederson,
M. R.; Singh, D. J.; Fiolhais, C. Phys. ReV. 1992, B46, 6671.
(43) Perdew, J. P.; Chevary, J. A.; Vosko, S. H.; Jackson, K. A.; Pederson,
M. R.; Singh, D. J.; Fiolhais, C. Phys. ReV. 1993, B48, 4978.
(44) Perdew, J. P.; Burke, K.; Wang, Y. Phys. ReV. 1996, B54, 16553.
(45) Scott, A. P.; Radom, L. J. Phys. Chem. 1996, 100, 16502.
(46) Godbout, N.; Salahub, D. R.; Andzelm, J.; Wimmer, E. Can. J. Chem.
1992, 70, 560.
(49) Haas et al. have reported the preparation of 2 by the reactions of Se-
12
(NSO)2 with TeCl4 and [(Me3Si)2N]2S with TeCl4 and SeCl4.9
(50) Cl2SeS2N229 that also contains the NdSdN fragment has been reported
to exhibit two 14N resonances at -51.7 and -137.8 ppm. The ionic
nature of the five-membered ring and the higher electronegativity of
sulfur and selenium compared to that of tellurium may explain the
minor differences in chemical shifts.
(51) Raman spectrum was recorded both from the reaction precipitate and
from the crystals to verify the identity of the products.
Inorganic Chemistry, Vol. 44, No. 14, 2005 4995

Konu et al.
Table 2. Fundamental Vibrations (cm-1) of Cl2TeS2N2 (1) and Cl2TeSeSN2 (2)
Cl2TeS2N2 (1)
Cl2TeSeSN2 (2)
obs. Ia ECPb Ic DZVPd Ie
obs. Ia ECPb Ic DZVPd Ie
assignmentf
assignmentf
1022 vw 1061 10 1064 16 a′
ν
ν
SN 73 νTeN 10
1034 vw 1068
1021 vw
7
1072
962
12 a′
57 a′
ν
ν
SN 56 νSeN 15 νTeN 11
SN 52 νTeN 15 νSeN 13
943 w
959 32
959
40 a′
SN 65 νTeN 15
SN 58 δSNS 19
943 w
965 43
687 vw
609 vw 607 10
689 vw 700
603 vw 603
9
6
707
599
503
8 a′
5 a′
44 a′
ν
ν
ν
614
570
10 a′
3 a′
ν
ν
SeN 31 δSeNS 21 δNSN 18
TeN 29 δTeNS 20 νSeN 14 νSN 12
TeN 25 δNSN 21 δTeN S 20 δSNS 11 560 vw 580
TeN 31 δSNS 18 νSN 12
3
502 m
511 41
489 w
265 + 225
38 a′ νTeN 31 νSeN 19 δSeNS 12 δNSN 10
430 m
454 41
443
361 vw 325
1
325
1 a′′ τ 84
347 vw
225 + 122
333 m
268 vs
244 s
319 18
289
271 100
265
320
296
271 100 a′
269
244
20 a′
1 a′′ τ 50 νTeCl 40
TeCl 65 νTeS 11
1 a′′ τ 79 δClTe N 12
29 a′ TeS 36 νTeCl 15 τ 11
νTeS 27 δTeS N 16 νTeN 14 δSNS 10 332 w
326
286
1
3
324
292
268 10 0 a′
248
242
200
1 a′′ τ 82
1 a′′ τ 51 νTeCl 43
2
ν
299 vs
265 w
245 w
225 vs
148 m
122 m
107 s
269 10 0
247 10
244
ν
TeCl 75
TeSeN 15 δNTeSe 13 δTeNS 11 δSeNS 11
4 a′′ τ 80 δClTeN 13
24 a′ TeSe 40
1
12 a′ δ
246 24
ν
2
195 23
ν
189 vw
139 s
112 vs
102 vs
70 vw
110 16
118
99
66
21 a′′ τ 60 δClTe S 23 δClTe N 13
6 a′ τ 46 δClTe N 20 δClTe S 14
18 a′′ τ 84
88
86 15
64
63 16
7
97
91
74
62
6 a′ τ 36 δClTeN 25 δClTeCl 10
18 a′′ τ 57 δClTeSe 25 δClTeN 10
3 a′ τ 33 δClTeSe 20 δClTeCl 24 δClTeN 12
18 a′′ τ 85
89
64 15
63
7
92 m
4
2
73
2 a′ τ 55 δClTe S 19 δClTe N 14
a Observed relative intensity. b Calculated wavenumbers at B3PW91/ECP level of theory. c Calculated Raman intensities at B3PW91/ECP level of theory.
d Calculated wavenumbers at B3PW91/DZVP level of theory. e Calculated Raman intensities at B3PW91/DZVP level of theory. f Assignments are based on
B3PW91/DZVP level of theory.
Figure 1. The Raman spectra of 1 and 2 [a and b, respectively].
calculations of the vibrational frequencies and intensities and
is shown in Table 2. Both Cl2TeESN2 (E ) S, Se) species
belong to the point group Cs and therefore all 15 fundamental
vibrations are Raman active in both cases. It can be seen
from Table 2 that the wavenumbers and intensities of the
Figure 2. The structure of Cl2TeS2N2 (1) showing the two parallel chains
linked with Te‚‚‚Cl close contacts. Thermal ellipsoids are drawn at the 50%
probability level. Symmetry operations: A: -x, y, 0.5 - z. B: x, 1 - y,
calculated fundamental vibrations agree well with the
observed Raman lines both at B3PW91/RLC ECP and
B3PW91/DZVP level of theory. The main contributions to
the potential energy are indicated at the B3PW91/DZVP level
of theory. They are in close agreement with those calculated
at B3PW91/RLC ECP level.
Crystal Structures of Cl2TeESN2 (E ) S, Se). The
structure of Cl2TeS2N2 (1) with the atomic numbering scheme
is shown in Figure 2. The molecule consists of a planar five-
membered ring with the tellurium atom bonded to two
exocyclic chlorine atoms. Unlike analogous Cl2TeSeSN2 (2)
(Figure 3),30 the structure of 1 shows no Te‚‚‚N close
contacts, but there are three Te‚‚‚Cl secondary bonds between
the neighboring molecules.
0.5 + z. C: x, 1 - y, z - 0.5.
The relevant bond parameters of 1 and 2 are summarized
in Table 3. The S-N bond lengths in the NSN fragment of
1 [1.542(3) and 1.583(3) Å] are similar to those in 2 [1.543-
(9)-1.558(9) Å] and indicate double bond character.52 The
corresponding bonds in (ClTeS2N2)2(Cl)[AsF6)] [1.53(1)-
1.57(1) Å],9 (ClTeSeSN2)[AsF6] [1.54(1) Å],10 and Cl2SeS2N2
[1.540(7)-1.550(7) Å]29 are also in close agreement. The
Te-N bond length [2.038(3) Å] in 1 is shorter than the single
(52) The SdN double bond length of 1.516(6) Å is observed in (ONS)2Se53
by X-ray crystallography and that of 1.536(3) Å is observed in Me3-
54
SiNdSdNSiMe3 by electron diffraction. The S-N single bond
length of 1.716(3) Å is exhibited by (Me3Si)2N-S-N(SiMe3)2.55
4996 Inorganic Chemistry, Vol. 44, No. 14, 2005

Applications of (Me3SiNSN)2E in Chalcogen-Nitrogen Chemistry
Table 3. Selected Bond Parameters for Cl2TeS2N2 (1) and Cl2TeSeSN2 (2)
1
2
1
2
S(1)-N(1)
S(1)-N(2)
Te(1)-N(1)
E-N(2)
1.542(3)
1.583(3)
2.038(3)
1.618(3)a
2.4316(8)a
2.6380(9)
1.558(9)
1.543(9)
1.994(8)
1.781(9)b
2.531(1)b
2.418(2)
Te(1)-Cl(2)
2.4894(9)
3.0393(8)c
3.2266(9)d
3.6360(8)e
2.770(2)
3.568(3)f
2.925(3)g
Te(1)‚‚‚Cl(1A)
Te(1)‚‚‚Cl(2B)
Te(1)‚‚‚Cl(1C)
Te(1)‚‚‚(N1C)
Te(1)-E
3.171(8)h
Te(1)-Cl(1)
N(1)-S(1)-N(2)
S(1)-N(1)-Te(1 )
S(1)-N(2)-E
N(1)-Te(1)-E
N(2)-E-Te(1)
115.2(2)
115.2(5)
N(1)-Te(1)-Cl(1)
N(1)-Te(1)-Cl(2)
E-Te(1)-Cl(1)
90.63(8)
89.48(8)
90.09(3)a
90.43(3)a
179.48(3)
88.4(2)
85.0(2)
115.9(2)
121.9(2)a
87.20(8)a
99.4(1)a
119.2(5)
122.6(5)b
88.1(2)b
94.6(3)b
94.05(7)b
86.72(6)b
173.31(8)
E-Te(1)-Cl(2)
Cl(1)-Te(1)-Cl(2)
a E ) S(2). b E ) Se(1). c -x, y, 0.5 - z. d x, 1 - y, 0.5 + z. e x, 1 - y, z - 0.5. f 0.5 - x, y - 0.5, z. g 0.5 - x, y + 0.5, z. h 1 - x, -y, -z.
(ClTeS2N2)2(Cl)[AsF6],9 indicating a single bond length. The
Te-Cl(1) and Te-Cl(2) bond lengths [2.6380(9) and 2.4894-
(9) Å, respectively] are significantly longer than the sum of
the covalent radii for tellurium and chlorine (2.36 Å)57 but
are relatively close to the bond lengths of 2.770(2) and 2.418-
(2) Å found in Cl2TeSeSN2. The lengthening of these bonds
is due to the intermolecular Te‚‚‚Cl close contacts.
The two intermolecular Te‚‚‚Cl close contacts [3.0393(8)
and 3.2266(9) Å] are significantly shorter than the sum of
the van der Waals radii of 4.01 Å57 for tellurium and chlorine
and link the adjacent molecules into two parallel chains
(Figure 2). In addition, the structure includes a third Te‚‚‚
Cl close contact that is weaker than the other two [3.6360-
(8) Å]. These three Te‚‚‚Cl close contacts expand the
coordination number of the tellurium atom to seven. This is
a typical example of the concept of secondary bonding
interaction that has been introduced by Alcock.61
Figure 3. The structure of Cl2TeSeSN2 (2) showing one Te‚‚‚N and two
Formation of Cl2TeESN2 (E ) S, Se). Haas et al.62 have
Te‚‚‚Cl close contacts. Thermal ellipsoids are drawn at the 50% probability
level. Symmetry operations: A: 0.5 - x, y - 0.5, z. B: 0.5 - x, y + 0.5,
z. C: 1 - x, -y, -z.
reported that the condensation of TeX4 (X ) F, Cl) with
(Me3SiNSN)2S affords eight-membered ring molecules [X2-
bond length56 being close to those in [(Me3Si)2N]2Te [2.045-
(2) and 2.053(2) Å]58 and Te(NSO)2 [2.039(7) Å].59 It is
somewhat longer than the Te-N bonds in the cationic species
(ClTeS2N2)2(Cl)[AsF6] [1.972(7)-1.987(8) Å]9 and (ClTe-
TeSeSN2)[AsF6] [2.00(1) Å].10 Interestingly, it is also slightly
longer than the Te-N bond of 1.994(8) Å in Cl2TeSeSN2.
The S(2)-N(2) bond [1.618(3) Å] in 1 is somewhat shorter
than the single bond of 1.716(3) Å in [(Me3Si)2N]2S55 and
is also slightly shorter than the corresponding S-N bonds
in the cation of (ClTeS2N2)2(Cl)[AsF6] [1.652(7) and 1.63-
(1) Å]9 and [(S3N2)Cl]2 [1.618(3) and 1.642(4) Å].60 The
Te-S bond [2.4316(8) Å] is close to the sum of the covalent
radii for tellurium and sulfur (2.41 Å)57 and is also near to
the bond lengths of 2.420(4) and 2.411(4) Å found in
Te(µ-NSN)2S] (X ) F, Cl) as a result of the cleavage of
Si-N bonds and the elimination of Me3SiCl followed by a
ring closure. We have recently reported that the reactions of
(Me3SiNSN)2E and E′Cl2 (E, E′ ) S or Se) involve a
cleavage of the E-N bond in the middle of the NSN-E-
NSN chain yielding eight-membered cage compounds
(EE′S2N4) possibly via dimerization of cyclic, four-membered
intermediates (ENSN and E′NSN, Scheme 2a).16
The reactions between (Me3SiNSN)2E (E ) S, Se) and
TeCl4 seem to follow a slightly different pathway by
producing nonionic, five-membered Cl2TeESN2 ring com-
pounds with several byproducts, as shown in eq 1.
The reaction is probably initiated by the cleavage of one
Si-N bond and the elimination of Me3SiCl followed by the
formation of an intermediate Cl3TeNSNENSNSiMe3 (Scheme
2b). Subsequent elimination of another molecule of Me3-
SiCl and N2 yields Cl2TeESN2 and S4N4. The reaction of
(Me3SiNSN)2S with SeCl4 leads to the formation of SeCl2
and S4N4 (Scheme 2c), as concluded by NMR spectroscopy.63
It seems that the reduction of SeCl4 to SeCl2 is more
favorable than that of TeCl4 to TeCl2 and could provide an
(53) Haas, A.; Kasprowski, J.; Angermund, K.; Betz, P.; Kruger, C.; Tsay,
Y.-H.; Werner, S. Chem. Ber. 1991, 124, 1895.
(54) Anderson, D. G.; Robertson, H. E.; Rankin, D. W. H.; Woollins, J.
D. J. Chem. Soc., Dalton Trans. 1989, 859.
(55) Schubert, G.; Kiel, G.; Gattow, G. Z. Anorg. Allg. Chem. 1989, 575,
129.
(56) The sum of the covalent radii for tellurium and nitrogen is 2.07 Å.57
(57) Emsley, J. The Elements, 3rd ed.; Clarendon Press: Oxford, U.K.,
1998.
(58) Bjo¨rgvinsson, M.; Roesky, H. W.; Pauer, F.; Stalke, D.; Sheldrick,
G. M. Inorg. Chem. 1990, 29, 5140.
(59) Haas, A.; Pohl, R. Chimia 1989, 43, 261.
(61) Alcock, N. W.; Harrison, W. D. J. Chem. Soc., Dalton Trans. 1982,
251.
(60) Small, R. W. H.; Banister, A. J.; Hauptman, Z. V. J. Chem. Soc.,
Dalton Trans. 1984, 1377.
(62) Boese, R.; Haas, A.; Hoppmann, E.; Merz, K.; Olteanu, A. Z. Anorg.
Allg. Chem. 2002, 628, 673.
Inorganic Chemistry, Vol. 44, No. 14, 2005 4997

Konu et al.
Scheme 2
explanation for the differing routes in reactions involving
TeCl4 and SeCl4.
Crystal Structures of 4a and 4b. The X-ray crystal
structures of 4a and 4b are shown in Figure 4. The relevant
bond parameters are summarized in Table 4. The anions in
both cases are isostructural and effectively analogous to those
in [PPh4]2[Pd2(µ-S2N2S)Br4].23 In 4a and 4b, the two
selenium atoms are in the bridging positions. The planar,
five-membered Se2N2S ligand thus links the two PdX2 units
in 4a and 4b via Pd-Se bonds of average length of 2.382
and 2.391 Å, respectively, resulting in square-planar geom-
etry around the Pd atom. The Pd-Se bond lengths are
comparable to those of 2.389(1) and 2.335(1) Å observed
for [(PPh3)2N]2[Cl2Pd(µ-SePh)2PdCl2]‚MeCN65 that also
contains a three-coordinated, bridging selenium between two
Pd-atoms. Perhaps the most noteworthy feature of both
structures is the disparity of bond lengths within the Se2N2S
ligands in 4a and 4b: The Se-N bond lengths are compa-
rable to the single bond distances of 1.844(3), 1.827(5), and
1.869(2) Å observed for (Me3SiNSN)2Se,16 (OSN)2Se,53 and
[(Me3Si)2N]2Se,58 respectively. By contrast, the S-N dis-
tances are 1.551(4) and 1.555(4) Å in 4a and 1.553(3) and
Reactions of (Me3SiNSN)2Se with [PPh4]2[Pd2X6] (X )
Cl, Br). The reaction of (Me3SiNSN)2Se with [PPh4]2[Pd2X6]
in CH2Cl2 over the course of 48 h results in solutions from
which well-formed crystals of [PPh4]2[Pd2(µ-Se2N2S)X4]
(X ) Cl 4a, Br 4b) may be grown via slow diethyl ether
diffusion over the course of many days (eq 2).
2 (Me3SiNSN)2Se + [PPh4]2[Pd2X6] f
[PPh4]2[Pd2(µ-Se2N2S)X4] + 2Me3SiX + Me3SiSiMe3 +
3/2N2 + 3/4S4N4 (X ) Cl, Br) (2)
In both cases, the crystals are of sufficient size to make
separation from amorphous byproducts relatively easy and
yields of 47 (4a) and 58% (4b) are attainable in this manner.
(63) The reaction between SeCl4 and (Me3SiNSN)2S was conducted
similarily to those of (Me3SiNSN)2E (E ) S, Se) with TeCl4 (see
Experimental Section). Precipitation of Cl2SeS2N2 was not observed
during or after the reaction. NMR spectra of the reaction solution (CH2-
Cl2, 25 °C, δ): 13C 2.78 (Me3SiCl); 14N -256 (S4N4); 77Se 1766
(SeCl2). After a few hours, the 77Se NMR spectrum also showed a
resonance at δ 1279 (Se2Cl2) because of the disproportionation: 3
SeCl2 T Se2Cl2 + SeCl4.64 The resonance of SeCl4 was not observed
because of its low solubility in CH2Cl2.
(64) Maaninen, A.; Chivers, T.; Parvez, M.; Pietika¨inen, J.; Laitinen; R.
S. Inorg. Chem. 1999, 38, 4093.
(65) Liaw, W.-F.; Chou, S.-Y.; Jung, S.-J.; Lee, G.-H.; Peng, S.-M. Inorg.
Chim. Acta 1999, 286, 155.
4998 Inorganic Chemistry, Vol. 44, No. 14, 2005

Applications of (Me3SiNSN)2E in Chalcogen-Nitrogen Chemistry
Scheme 3
similarities, there are important contrasts between the reac-
tions. While the reactions involving (Me3SiNSN)2S also
generate salts of other anions, namely, [Pd(N3S2)Cl2]-,
[Pd(N3S2)Br2]-, and [Pd2(S2N2)Br6]2-,23 none of these appear
to form in the reactions of (Me3SiNSN)2Se, nor are any
partially selenated variations upon those systems found. This
suggests that the pathways for the reactions involving (Me3-
SiNSN)2Se are subtly different to those involving (Me3-
SiNSN)2S. In the latter case, reactions are dependent upon
the nature of the halide present, and initial products of the
type [Pd{(Me3SiNSN)2S}Cl3]- (with the incoming ligand
N-bound in monodentate fashion) and [Pd{(Me3SiNSN)2S}-
Br2]- (with bidentate ligand) were postulated (Scheme 3a,
b).23
Figure 4. Crystal structures of [PPh4]2[Pd2(µ-Se2N2S)X4] [X ) Cl (4a),
Br (4b)] indicating the atomic numbering scheme. Thermal ellipsoids are
drawn at the 50% probability level.
1.556(4) Å in 4b, which are values close to the double bond
lengths of sulfur and nitrogen.52 Thus, it would appear that
multiple bonding within the ligand is localized on the
NdSdN unit. In the case of [PPh4]2[Pd2(µ-S2N2S)Br4],23 the
delocalization of the double bond across the ligand is more
pronounced with the bond lengths of 1.61(5) and 1.56(4) Å
within the NdSdN unit and 1.65(3) and 1.64(5) Å for the
S-N single bonds.52 The Se atoms show a distorted
tetrahedral bonding environment. This is consistent with the
formal localization of the negative charge to the selenium
atoms. The [Pd2(µ-Se2N2S)X4]2- anions are surrounded by
the large (PPh4)+ cations and, therefore, no significant
intermolecular close contacts are observed in the structures
of 4a and 4b.
Formation of [PPh4]2[Pd2(µ-Se2N2S)X4] (X ) Cl, Br).
The anions within 4a and 4b are effectively analogous to
those found previously in [PPh4]2[Pd2(µ-S2N2S)X4] (X ) Cl,
Br) with the two selenium atoms occupying the bridging
positions.26 Indeed, it was the ability of (Me3SiNSN)2S to
act as a source of the latter species which prompted our
investigation into analogous reactions of (Me3SiNSN)2Se.
However, while the aforementioned products have clear
The presence of Pd-N bonds in both intermediates would
allow for ready formation of the complexes of [N3S2]- and
S2N2, and indeed the yield of the complexes of [S3N2]2- is
very low in both cases (these complexes can be formed in
much greater yield using S4N4 as starting material).26 The
relatively high yields of the Pd-Se bond-bearing anions in
4a and 4b suggest that a likely intermediate in both reactions
is one of the type [Pd{(Me3SiNSN)2Se}X3]- in which the
ligand is bound to the metal via the softer selenium atom
(Scheme 3c). We may then envisage two such units coming
together to rearrange; both Me3SiX and Me3SiSiMe3 can be
detected as products when the reactions are performed in
1
CD2Cl2 and monitored by H NMR.
Table 4. Selected Bond Lengths (Å) and Angles (°) of [PPh4]2[Pd2(µ-Se2N2S)Cl4] (4a) and [PPh4]2[Pd2(µ-Se2N2S)Br4] (4b)
4a
4b
4a
4b
Se(1)-N(1)
Se(2)-N(2)
S(1)-N(1)
S(1)-N(2)
Se(1)-Pd(1)
Se(1)-Pd(2)
1.831(4)
1.835(4)
1.551(4)
1.555(4)
2.3842(6)
2.3703(6)
1.829(3)
1.829(3)
1.556(4)
1.553(3)
2.3898(5)
2.3749(5)
Se(2)-Pd(1)
Se(2)-Pd(2)
Pd(1)-X(1)
Pd(1)-X(2)
Pd(2)-X(3)
Pd(2)-X(4)
2.3796(6)
2.3837(6)
2.360(1)
2.364(1)
2.337(1)
2.365(1)
2.3884(4)
2.3940(4)
2.4750(5)
2.4796(5)
2.4548(5)
2.4832(5)
Se(1)-N(1)-S(1)
N(1)-S(1)-N(2)
S(1)-N(2)-Se(2)
Se(1)-Pd(1)-Se(2)
Se(1)-Pd(2)-Se(2)
Pd(1)-Se(1)-N(1)
Pd(1)-Se(2)-N(2)
Pd(2)-Se(1)-N(1)
Pd(2)-Se(2)-N(2)
Pd(1)-Se(1)-Pd(2)
126.3(2)
126.5(2)
Pd(1)-Se(2)-Pd(2)
Se(1)-Pd(1)-X(1)
Se(1)-Pd(1)-X(2)
Se(1)-Pd(2)-X(3)
Se(1)-Pd(2)-X(4)
Se(2)-Pd(1)-X(1)
Se(2)-Pd(1)-X(2)
Se(2)-Pd(2)-X(3)
Se(2)-Pd(2)-X(4)
82.04(2)
173.51(3)
90.13(3)
87.46(3)
174.06(3)
88.81(3)
174.12(4)
171.96(4)
90.83(3)
80.33(1)
173.82(2)
90.07(2)
86.88(2)
174.28(2)
88.66(2)
173.81(2)
171.87(2)
90.89(2)
122.8(2)
126.2(2)
84.97(2)
85.19(2)
104.1(1)
104.2(1)
104.6(1)
103.5(1)
82.23(2)
122.7(2)
127.0(2)
85.52(2)
85.72(2)
103.3(1)
105.0(1)
105.0(1)
103.3(1)
80.69(2)
Inorganic Chemistry, Vol. 44, No. 14, 2005 4999

Konu et al.
Conclusions
Acknowledgment. The financial support from the Acad-
emy of Finland, Emil Aaltonen Foundation, Finnish Cultural
Foundation’s Regional Fund of North Ostrobothnia, NSERC
(Canada), EPSRC (UK) for provision of PDRA is gratefully
acknowledged. We also thank Johnson Matthey for loans of
precious metals.
While the reactions of (Me3SiNSN)2E with E′Cl2 (E ) S,
Se) afford eight-membered cage molecules, EE′S2N4,16 the
reactions of (Me3SiNSN)2E with TeCl4 (E ) S, Se) produce
five-membered rings, Cl2TeESN2, as the main products. The
products were characterized by X-ray crystallography, NMR,
and Raman and mass spectroscopy. The isolation of [PPh4]2-
[Pd2(µ-Se2N2S)X4] confirms the potential of (Me3SiNSN)2Se
as a synthon within transition-metal chemistry. It also
indicates that it is possible to introduce selenium into larger
chalcogen-nitrogen ligand systems, suggesting that many
more await discovery.
Supporting Information Available: X-ray crystallographic
files, in CIF format. This material is available free of charge via
the Internet at http://pubs.acs.org.
IC050261F
5000 Inorganic Chemistry, Vol. 44, No. 14, 2005