Cation-anion interactions in triphenyl telluronium salts. The crystal structures of (Ph3Te)2[MCl6] (M=Pt, Ir), (Ph3Te)[AuCl4], and (Ph3Te)(NO3)·HNO3

Article abstract of DOI:10.1016/S0022-328X(01)01182-2

Triphenyltelluronium hexachloroplatinate (1), hexachloroiridate (2), tetrachloroaurate (3), and tetrachloroplatinate (4) were prepared from Ph₃TeCl and potassium salts of the corresponding anions. Upon recrystallization of 4 from concentrated nitric acid, K₂[PtCl₆] and (Ph₃Te)(NO₃)·HNO₃ (5) were obtained. The crystal structures of 1-3 and 5 are reported. Compounds 1 and 2 are isostructural. They are triclinic, P1?, Z=2 (the asymmetric unit contains two formula units). Compound 1: a=10.7535(2), b=17.2060(1), c=21.4700(3) A?, α=78.9731(7), β=77.8650(4), γ=78.8369(4)°. Compound 2: a=10.7484(2), b=17.1955(2), c=21.4744(2) A?, α=78.834(1), β=77.649(1), γ=78.781(1)°. Compound 3 is monoclinic, P2₁/c, Z=4, a=8.432(2), b=14.037(3), c=17.306(3) A?, β=93.70(3)°. Compound 5 is monoclinic. P2₁/n, Z=4, a=9.572(2), b=14.050(3), c=13.556(3) A?, β=90.76(3)°. The primary bonding in the Ph₃Te⁺ cation in each salt is a trigonal AX₃E pyramid with Te-C bond lengths in the range 2.095(8)-2.14(2) A? and the bond angles 94.1(6)-100.9(5)°. The weak TeCl (1-3) and TeO (5) secondary interactions expand the coordination sphere. In 1 and 2 the cation shows a trigonal bipyramidal AX₃YE coordination with one primary Te-C bond and the shortest secondary TeCl contact in axial positions and the two other Te-C bonds and the lone-pair in equatorial positions. The cation in 3 shows a distorted octahedral AX₃Y₃E environment and that in 5 is a more complex AX₃Y₃Y′₂ arrangement. In both latter salts the structure is a complicated three-dimensional network of cations and anions.

Full text of DOI:10.1016/S0022-328X(01)01182-2

Journal of Organometallic Chemistry 640 (2001) 50–56
www.elsevier.com/locate/jorganchem
Cation–anion interactions in triphenyl telluronium salts. The
crystal structures of (Ph3Te)2[MCl6] (M=Pt, Ir), (Ph3Te)[AuCl4],
and (Ph3Te)(NO3)·HNO3
Raija Oilunkaniemi a, Jarkko Pietika¨inen a, Risto S. Laitinen a,*, Markku Ahlgre´n b
a Department of Chemistry, P.O. Box 3000, Uni6ersity of Oulu, FIN-90014 Oulu, Finland
b Department of Chemistry, Uni6ersity of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland
Received 14 May 2001; accepted 10 August 2001
Abstract
Triphenyltelluronium hexachloroplatinate (1), hexachloroiridate (2), tetrachloroaurate (3), and tetrachloroplatinate (4) were
prepared from Ph3TeCl and potassium salts of the corresponding anions. Upon recrystallization of 4 from concentrated nitric
acid, K2[PtCl6] and (Ph3Te)(NO3)·HNO3 (5) were obtained. The crystal structures of 1–3 and 5 are reported. Compounds 1 and
(
2 are isostructural. They are triclinic, P1, Z=2 (the asymmetric unit contains two formula units). Compound 1: a=10.7535(2),
,
b=17.2060(1), c=21.4700(3) A, h=78.9731(7), i=77.8650(4), k=78.8369(4)°. Compound 2: a=10.7484(2), b=17.1955(2),
,
c=21.4744(2) A, h=78.834(1), i=77.649(1), k=78.781(1)°. Compound 3 is monoclinic, P21/c, Z=4, a=8.432(2), b=
,
,
14.037(3), c=17.306(3) A, i=93.70(3)°. Compound 5 is monoclinic. P21/n, Z=4, a=9.572(2), b=14.050(3), c=13.556(3) A,
i=90.76(3)°. The primary bonding in the Ph3Te+ cation in each salt is a trigonal AX3E pyramid with TeꢀC bond lengths in the
,
range 2.095(8)–2.14(2) A and the bond angles 94.1(6)–100.9(5)°. The weak Te···Cl (1–3) and Te···O (5) secondary interactions
expand the coordination sphere. In 1 and 2 the cation shows a trigonal bipyramidal AX3YE coordination with one primary TeꢀC
bond and the shortest secondary Te···Cl contact in axial positions and the two other TeꢀC bonds and the lone-pair in equatorial
positions. The cation in 3 shows a distorted octahedral AX3Y3E environment and that in 5 is a more complex AX3Y3Y2%
arrangement. In both latter salts the structure is a complicated three-dimensional network of cations and anions. © 2001 Elsevier
Science B.V. All rights reserved.
Keywords: Triphenyltelluronium; Tetrachloroaurate; Tetrachloroplatinate; Hexachloroplatinate; Hexachloroiridate; Crystal structures
1. Introduction
tellurium–anion interactions [15] that expand the AX3E
(X=bonding pair, E=lone pair) trigonal pyramidal
geometry around tellurium into a five- or six-coordinate
entity. In the absence of these secondary interactions,
simple ionic structures are expected [16]. Christian et al.
[17] and Collins et al. [13] have discussed the nature of
the secondary bonding and rationalized the structures
in terms of the coordination geometry around tel-
lurium. It has also been shown that solid-state 125Te-
NMR spectroscopy is a sensitive tool for identification
of covalent secondary bonding interactions between the
cations and anions [13].
The present study is concerned with the structure and
bonding of Ph3Te+ cation with relatively large counte-
rions. Octahedral hexachloroplatinate [PtCl6]2− and -
iridate [IrCl6]2− as well as square planar [AuCl4]− and
[PtCl4]2− were chosen to establish the effect of the
Organotelluronium salts, R3TeX, have been known
for over a century [1]. In recent years they have at-
tracted considerable interest because of their role in
organic synthetic chemistry. For example, it has been
reported that the telluronium salts are precursors for
telluronium ylides that react with the carbonyl com-
pounds forming a variety of products like oxiranes and
secondary alcohols [2].
The X-ray structure determinations of several organ-
otelluronium salts (for some representative examples,
see Refs. [3–14]) have established that in the solid state
the structural features are governed by weak secondary
* Corresponding author. Tel.: +358-553-1608.
E-mail address: risto.laitinen@oulu.fi (R.S. Laitinen).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)01182-2

R. Oilunkaniemi et al. / Journal of Organometallic Chemistry 640 (2001) 50–56
51
geometry and the charge of the anion on the cation–
2.2. X-ray diffraction
anion interactions.
Diffraction data for 1–3 and 5 were collected on a
Nonius Kappa CCD diffractometer using graphite
,
monochromated Mo–Ka radiation (u=0.71073 A) by
2. Experimental
recording 360 frames via 8-rotation (D€=1°; two
times 10–20 s per frame). Crystal data and the details
of the structure determinations are given in Table 1. All
2.1. Syntheses
structures were solved by direct methods using SHELXS
-
2.1.1. General
97 [20] and refined using SHELXL-97 [21]. After the
full-matrix least-squares refinement of the non-hydro-
gen atoms with anisotropic thermal parameters, the
hydrogen atoms in 1–3 were placed in calculated posi-
The preparation of Ph3TeCl was carried out as de-
scribed in the literature [18]. K[AuCl4], K2[PtCl6] and
K2[IrCl6] (Aldrich) were used without further purifica-
tion. K2[PtCl4] was prepared by reducing K2[PtCl6] with
N2H4·2HCl [19].
,
tions in the aromatic rings (CꢀH=0.93 A). In the final
refinement the hydrogen atoms were riding with the
carbon atom they were bonded to. The isotropic ther-
mal parameters of the hydrogen atoms were fixed at 1.2
times that of the corresponding carbon atom. In the
case of 5, the aromatic hydrogen atoms were treated as
described above. The acidic hydrogen atom of the nitric
acid molecule, however, could be located in the differ-
ence Fourier map after anisotropic refinement of all
non-hydrogen atoms. Its position could be refined in-
volving an isotropic thermal parameter.
The scattering factors for the neutral atoms were
those incorporated with the programs. Fractional coor-
dinates of all atoms, anisotropic thermal parameters,
and the full listing of bond parameters are available as
supplementary material.
2.1.2. (Ph3Te)2[PtCl6] (1) and (Ph3Te)2[IrCl6] (2)
Ph3TeCl (162 mg, 0.42 mmol) in 5 ml of EtOH was
added into 5 ml of a hot aqueous solution containing
100 mg (0.21 mmol) of K2[PtCl6] or K2[IrCl6] resulting
in the immediate formation of an orange–yellow or
brown precipitate, respectively. The precipitates were
filtered, washed with water and EtOH, and dried. Upon
recrystallization from nitric acid, orange crystals of
[Ph3Te]2[PtCl6] or dark red crystals of [Ph3Te]2[IrCl6]
were obtained. Yield: 1, 205 mg (88%); 2, 165 mg
(71%). Anal. Found: C, 38.47; H, 2.56. Calc. for
C36H30Cl6PtTe2 (1): C, 38.41; H, 2.69%. Anal. Found:
C, 38.54; H, 2.55. Calc. for C36H30Cl6IrTe2 (2): C,
38.51; H, 2.69%.
2.3. NMR spectroscopy
2.1.3. (Ph3Te)[AuCl4] (3)
Ph3TeCl (50 mg, 0.13 mmol) in 5 ml of EtOH was
added into 5 ml of an ethanolic solution containing 48
mg (0.13 mmol) of K[AuCl4]. The potassium chloride
precipitate was removed by filtration. Upon standing
for 3 days in 4 °C, yellow crystals of (Ph3Te)[AuCl4]
were obtained from the filtrate. Yield: 74 mg (85%).
Anal. Found: C, 31.12; H, 2.14. Calc. for
C18H15AuCl4Te (3): C, 31.00; H, 2.17%.
The 125Te spectra were recorded on a Bruker
DPX400 spectrometer operating at 126.24 MHz. The
spectral width was 101.522 kHz, the pulse width was
10.0 ms corresponding to the nuclear tip angle of 45°,
and the pulse delay was 1.6 s. Saturated solution of
H6TeO6 (aq.) was used as an external reference. The
spectrum was recorded unlocked. Chemical shifts are
reported relative to neat Me2Te. [l(Me2Te)=
l(H6TeO6)+712].
2.1.4. (Ph3Te)2[PtCl4] (4)
Ph3TeCl (212 mg, 0.55 mmol) in 5 ml of water was
added into 5 ml of a hot aqueous solution containing
112 mg (0.27 mmol) of K2[PtCl4]. A pale brown precip-
itate was obtained almost immediately. The precipitate
was filtered, washed with water and Et2O, and dried.
Yield: 155 mg (55%). Anal. Found: C, 40.63; H, 2.63.
Calc. for C36H30Cl4PtTe2: C, 41.00; H, 2.87%.
The recrystallization of 4 from nitric acid with the
addition of N2H4·2HCl afforded both yellow and
colourless crystals. Yellow crystals turned out to be
K2[PtCl6] and the colourless crystals (Ph3Te)-
(NO3)·HNO3 (5). Anal. Found: C, 43.94; H, 3.28; N,
5.60. Calc. for C18H16N2O6Te (5): C, 44.67; H, 3.33; N,
5.79%.
3. Results and discussion
3.1. General
The formation of the salts 1–4 is a straightforward
metathesis reaction:
nPh3TeCl+KnMClx“(Ph3Te)n[MClx]
+nKCl (M=Pt, Ir, Au; x=4, 6; n=1, 2)
(Ph3Te)2[PtCl6] (1) and (Ph3Te)2[IrCl6] (2) are only
slightly soluble in water and in ethanol and precipitate

52
R. Oilunkaniemi et al. / Journal of Organometallic Chemistry 640 (2001) 50–56
Table 1
Details of the structure determination of (Ph3Te)2[PtCl6] (1), (Ph3Te)2[IrCl6] (2), (Ph3Te)[AuCl4] (3), and (Ph3Te)(NO3)·HNO3 (5)
Compound
(Ph3Te)2[PtCl6] (1)
(Ph3Te)2[IrCl6] (2)
(Ph3Te)[AuCl4] (3) (Ph3Te)(NO3)·HNO3 (5)
Empirical formula
Relative molecular mass
Crystal system
C36H30Cl6PtTe2
1125.59
Triclinic
C36H30Cl6IrTe2
1122.70
Triclinic
C18H15Cl4TeAu
697.67
Monoclinic
P21/c
8.432(2)
14.037(3)
17.306(3)
C18H16N2O6Te
483.98
Monoclinic
P21/n
9.572(2)
14.050(3)
13.556(3)
(
(
Space group
P1
P1
,
a (A)
10.7535(2)
17.2060(1)
21.4700(3)
78.9731(7)
77.8650(4)
78.8369(4)
3763.0(1)
4 a
10.7484(2)
17.1955(2)
21.4744(2)
78.834(1)
77.649(1)
78.781(1)
3754.9(1)
4 a
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
93.70(3)
90.76(3)
3
,
V (A )
Z
2044.1(7)
4
2.267
1822.9(6)
4
1.763
zcalc (g cm−1
T (K)
)
1.987
293
1.986
293
150
150
F(000)
2120
5.700
2116
5.531
1288
9.117
952
1.670
v(Mo–Ka) (mm−1
)
Crystal size (mm)
0.40×0.35×0.10
26 868
13 567
10 894
0.0237
0.0383
0.0837
0.0533
0.0892
0.25×0.20×0.10
34 934
13 809
11 536
0.0284
0.0634
0.1529
0.0758
0.1570
0.20×0.10×0.10
12 770
4989
0.30×0.30×0.20
12 787
3569
Number of reflections collected
Number of unique reflections
Number of observed reflections [I\2s(I)]
Rint
4521
3077
0.0353
0.0267
0.0568
0.0326
0.0589
0.0862
0.0374
0.0914
0.0455
0.0964
b
R1
b
wR2
R1 (all data) b
wR2 (all data) b
a The asymmetric unit contains two independent (Ph3Te)2[MCl6] (M=Pt, Ir) units.
b R1=SꢀꢀFoꢀ−ꢀFcꢀꢀ/SꢀFoꢀ, wR2=[Sw(ꢀFoꢀ−ꢀFcꢀ)2/SwF2o]1/2
.
immediately upon mixing of the reagents. Single crys-
tals that are suitable for the X-ray structure determina-
tion were obtained by recrystallization from
concentrated nitric acid. (Ph3Te)[AuCl4] (3) is soluble in
ethanol and X-ray quality crystals were obtained upon
prolonged standing at a temperature slightly below the
ambient temperature.
of the Me3Te+, Bu2PhTe+, and MePh2Te+ cations in
CDCl3 have been reported to be 418, 543, and 675
ppm, respectively [2]. The resonance is shifted upfield in
an almost linear fashion as the number of phenyl
groups in the cation increases. It can be concluded that
125Te-NMR spectroscopy has confirmed the existence of
discrete Ph3Te+ cations in all solutions.
The recrystallization of the ale brown precipitate of
(Ph3Te)2[PtCl4] (4) by evaporating a concentrated nitric
acid solution with the prior addition of N2H4·2HCl
afforded a mixture of yellow and colourless crystals.
The unit cell parameters and the space group of the
yellow crystals indicated them to be K2[PtCl6].1 The
colourless crystals were shown to be (Ph3Te)(NO3)·
HNO3 (5) by X-ray crystallography.
3.3. Crystal structures
The crystal structures of (Ph3Te)2[MCl6] [M=Pt (1)
and Ir (2)] are shown in Fig. 1. Those of (Ph3Te)[AuCl4]
(3) and (Ph3Te)(NO3)·HNO3 (5) are shown in Figs. 2
and 3, respectively. All compounds are composed of
discrete ions.
The selected bond parameters of 1–3 are shown in
Table 2 and those for 5 in Table 3. The TeꢀC distances
3.2. NMR spectra
,
span ranges of 2.095(8)–2.131(8) A in 1, 2.09(2)–
The 125Te-NMR spectra of the compounds 1–4 were
recorded in nitric acid. Only one resonance at 754 ppm
appears in every solution. The 125Te-NMR spectrum of
(Ph3Te)[AuCl4] was also recorded in ethanol and exhib-
ited one resonance at 788 ppm. The resonance of
Ph3TeCl was observed at 754 and 788 ppm in nitric
acid and ethanol, respectively. The 125Te chemical shifts
,
,
2.14(2) A in 2, 2.112(4)–2.122(4) A in 3, and 2.117(3)–
,
2.120(3) A in 5. These values are quite normal and
compare well with those in related aromatic telluro-
nium salts, as exemplified by the mean TeꢀCaryl bond
,
lengths of 2.13(2) and 2.130(4) A in (Ph3Te)(NCS) [7]
and Ph3TeCl [8], respectively. The bond parameters of
the cations in several telluronium salts reported by
Collins et al. [13] are also consistent with those of the
present salts. The primary TeꢀC bonds expectedly de-
1
,
,
Cubic, a=9.743(1) A, space group Fm3m {c.f. 9.751(5) A [22]}.

R. Oilunkaniemi et al. / Journal of Organometallic Chemistry 640 (2001) 50–56
53
Fig. 3. The molecular structure of (Ph3Te)(NO3)(HNO3) (5) indicat-
ing the numbering of the atoms. The thermal ellipsoids are drawn at
50% probability level.
pict a AX3E trigonal pyramid with the CꢀTeꢀC angles
varying between 93.5(3) and 100.9(3)° (mean value
96.8°) in 1, 94.1(6) and 100.9(5)° (mean value 96.9°) in
2, 96.5(1) and 98.7(1)° in 3, and 96.3(1) and 98.0(1)°
(mean value 97.0°) in 5. These values are also quite
typical (see also Refs. [2–14]).
The orientation of the phenyl rings in the cations can
be defined in terms of the angles between the rings and
the two opposite TeꢀC bonds as shown in Fig. 4. Many
phenyl rings show a tendency to be approximately
parallel with one of the two TeꢀC bonds and perpendic-
ular to the other. This is consistent with the earlier
observation that in aromatic dichalcogenides the planes
of the aromatic groups tend to be either parallel or
perpendicular to the chalcogen–chalcogen bonds [23].
In the absence of steric effects the orientation of the
ring seems to depend on its electron-withdrawing na-
ture. In the present salts, however, the packing interac-
tions cause deviations from the coplanarity.
Fig. 1. The molecular structure of (Ph3Te)2[MCl6] [M=Pt (1), Ir (2)]
indicating the numbering of the atoms. The thermal ellipsoids are
drawn at 50% probability level. The atom M(1) occupies a general
position with six independent Cl− ligands. The atoms M(2) and M(3)
occupy a special position with three independent Cl− ligands. The
octahedra are completed by symmetry. Hydrogen atoms have been
omitted for clarity.
The bond parameters in the anions of 1–3 are quite
normal. The three crystallographically independent
[MCl6]2− anions in both 1 and 2 are almost regular
octahedra with the bond lengths in the range 2.317(2)–
,
,
2.334(2) A in 1 and 2.322(4)–2.342(4) A in 2. The
tetrachloroaurate anion in 3 is also a virtually regular
square-plane with the AuꢀCl bond lengths of 2.273(1)–
,
2.294(1) A.
The lattice of 5 incorporates both a nitrate ion and a
free nitric acid molecule. The nitrate ions and nitric
acid molecules are bound together with a strong, al-
most symmetric O(1)ꢀH(1)···O(4) hydrogen bond ar-
rangement (see Table 3). The H(1)ꢀO(1) bond shows a
,
length of 1.18(7) A and the H(1)···O(4) distance is
,
1.32(7) A. The O(1)ꢀH(1)···O(4) angle is 159(6)°. The
Fig. 2. The molecular structure of (Ph3Te)[AuCl4] (3) indicating the
numbering of the atoms. The thermal ellipsoids are drawn at 50%
probability level. The secondary bonding expands the coordination
around tellurium to a distorted AX3Y3E octahedron. Hydrogen
atoms have been omitted for clarity.
,
resulting O(1)···(O(4) distance of 2.455(4) A indicates a
very strong interaction. The N(1)ꢀO(1) and N(2)ꢀO(4)
bonds that are involved in the hydrogen bonding are
,
expectedly somewhat longer [1.320(4) and 1.318(4) A,

54
R. Oilunkaniemi et al. / Journal of Organometallic Chemistry 640 (2001) 50–56
Table 2
+
,
Selected bond lengths (A) and angles (°) in the Ph3Te cation of (Ph3Te)2[PtCl6] (1), (Ph3Te)2[IrCl6] (2), and (Ph3Te)[AuCl4] (3)
(a) (Ph3Te)2[PtCl6] (1) and (Ph3Te)2[IrCl6] (2)
1
2
1
2
Te(1)ꢀC(111)
Te(1)ꢀC(121)
Te(1)ꢀC(131)
Te(2)ꢀC(211)
Te(2)ꢀC(221)
Te(2)ꢀC(231)
Te(3)ꢀC(311)
Te(3)ꢀC(321)
Te(3)ꢀC(331)
Te(4)ꢀC(411)
Te(4)ꢀC(421)
Te(4)ꢀC(431)
2.116(7)
2.110(7)
2.131(8)
2.099(7)
2.115(8)
2.130(8)
2.095(8)
2.123(8)
2.101(8)
2.116(7)
2.120(8)
2.124(8)
2.13(1)
2.11(1)
2.14(2)
2.09(2)
2.12(1)
2.14(2)
2.09(2)
2.11(1)
2.12(1)
2.10(1)
2.12(1)
2.13(2)
C(111)ꢀTe(1)ꢀC(121)
C(111)ꢀTe(1)ꢀC(131)
C(121)ꢀTe(1)ꢀC(131)
C(211)ꢀTe(2)ꢀC(221)
C(211)ꢀTe(2)ꢀC(231)
C(221)ꢀTe(2)ꢀC(231)
C(311)ꢀTe(3)ꢀC(321)
C(311)ꢀTe(3)ꢀC(331)
C(321)ꢀTe(3)ꢀC(331)
C(411)ꢀTe(4)ꢀC(421)
C(411)ꢀTe(4)ꢀC(431)
C(421)ꢀTe(4)ꢀC(431)
99.4(3)
96.4(3)
95.1(3)
99.8(3)
95.1(3)
94.8(3)
97.6(3)
98.8(3)
95.1(4)
98.7(5)
96.2(6)
94.9(6)
100.4(6)
95.1(6)
94.7(6)
97.7(6)
99.2(6)
94.6(6)
100.9(5)
95.7(6)
94.1(6)
100.9(3)
95.5(3)
93.5(3)
(b) (Ph3Te)[AuCl4] (3)
Te(1)ꢀC(111)
Te(1)ꢀC(121)
2.112(4)
2.122(4)
2.114(4)
C(111)ꢀTe(1)ꢀC(121)
C(111)ꢀTe(1)ꢀC(131)
C(121)ꢀTe(1)ꢀC(131)
96.5(1)
98.7(1)
98.7(1)
Te(1)ꢀC(131)
respectively] than the NꢀO bonds not involved in the
secondary bonding arrangement with Cl(1)···Te(1)ꢀ
C(11), Cl(2)···Te(1)ꢀC(31), and Cl(3)···Te(1)ꢀC(21) an-
gles of 171.6, 159.0, and 162.7°, respectively.
,
hydrogen bonding [1.209(3)–1.232(3) A].
The packing arrangements and the geometry around
tellurium due to the secondary bonding can be com-
pared to those observed in Ph3TeCl [11] and
Ph3TeCl·12CH2Cl2 [12]. In the former the ions combine
to form discrete dimers. The Te···Cl distances range
3.4. Packing
The packing of ions in the lattice depends on the
geometry of the anions. In 1 and 2 each crystallograph-
ically independent [MCl6]2− show close contacts to two
Ph3Te+ cations on the opposite trigonal faces of the
octahedra (see Fig. 1). The resulting three Te···Cl close
contacts range 3.331(2)–3.843(2) and 3.313(4)–3.783(4)
Table 3
,
A in 1 and 2, respectively. The shortest distances are
,
Selected bond lengths (A) and angles (°) in (Ph3Te)(NO3)·(HNO3) (5)
clearly shorter than the sums of the van der Waals’
Bond lengths
,
radii of tellurium and chlorine of 4.01 A [24]. The
Te(1)ꢀC(111)
Te(1)ꢀC(121)
Te(1)ꢀC(131)
N(1)ꢀO(1)
N(1)ꢀO(2)
N(1)ꢀO(3)
2.117(3)
2.120(3)
2.118(4)
1.320(4)
1.210(4)
1.222(4)
N(2)ꢀO(4)
N(2)ꢀO(5)
N(2)ꢀO(6)
H(1)ꢀO(1)
H(1)ꢀO(4)
1.318(4)
1.209(4)
1.232(3)
1.18(7)
shortest Te···Cl secondary bonding interactions depict
an approximate trigonal bipyramidal AX3YE (Y=a
secondary bonding pair) bonding arrangement with the
lone-pair and two primary TeꢀC bonds occupying the
equatorial positions. The third TeꢀC bond and the
Te···Cl secondary interactions occupy the axial posi-
tions. As seen in Table 4, the axial TeꢀC bond in each
Ph3Te+ cation is expectedly somewhat longer than the
two equatorial bonds. The effect is very small and has
barely statistical significance, but is quite consistent.
This trend is in agreement with the trans-relationships
between the secondary and primary bonding discussed
by Christian et al. [17].
1.32(7)
Bond angles
C(111)ꢀTe(1)ꢀC(121)
C(111)ꢀTe(1)ꢀC(131)
C(121)ꢀTe(1)ꢀC(131)
O(1)ꢀN(1)ꢀO(2)
O(1)ꢀN(1)ꢀO(3)
O(2)ꢀN(1)ꢀO(3)
96.3(1)
98.0(1)
96.6(1)
116.9(3)
117.8(3)
125.2(3)
O(4)ꢀN(2)ꢀO(5)
O(4)ꢀN(2)ꢀO(6)
O(5)ꢀN(2)ꢀO(6)
N(1)ꢀO(1)ꢀH(1)
N(2)ꢀO(4)ꢀH(1)
O(1)ꢀH(1)ꢀO(4)
119.2(3)
116.2(3)
124.6(3)
103(3)
108(3)
159(6)
The discrete Ph3Te···MCl6···TePh3 units are further
joined together by weak hydrogen bonds involving
phenyl hydrogen atoms from the cation and chlorine
atoms of the anion.
In (Ph3Te)[AuCl4] (3) the cation and the anion form
a continuous network as shown in Fig. 2. Three Te···Cl
,
close contacts of 3.064(4)–3.400(1) A from three differ-
ent [AuCl4]− anions result in the octahedral coordina-
Fig. 4. The orientation of the phenyl ring with respect to the two
tion around tellurium and indicate
a
AX3Y3E
opposite TeꢀC bonds.

R. Oilunkaniemi et al. / Journal of Organometallic Chemistry 640 (2001) 50–56
55
Table 4
The trigonal bipyramidal AX3YE geometry of tellurium in (Ph3Te)2[PtCl6] (1) and (Ph3Te)2[IrCl6] (2)
(Ph3Te)2[PtCl6] (1)
(Ph3Te)2[IrCl6] (2)
,
,
,
,
Cl···Te (A)
TeꢀC (A)
Cl···TeꢀC (°)
Cl···Te (A)
TeꢀC (A)
Cl···TeꢀC (°)
Cl(12)···Te(1)
Cl(12)···Te(1)
Cl(12)···Te(1)
Cl(15)···Te(2)
Cl(15)···Te(2)
Cl(15)···Te(2)
Cl(22)···Te(3)
Cl(22)···Te(3)
Cl(22)···Te(3)
Cl(32)···Te(4)
Cl(32)···Te(4)
Cl(32)···Te(4)
C(111)
C(121)
C(131)
C(211)
C(221)
C(231)
C(311)
C(321)
C(331)
C(411)
C(421)
C(431)
3.411(2)
3.411(2)
3.411(2)
3.348(2)
3.348(2)
3.348(2)
3.416(2)
3.416(2)
3.416(2)
3.331(2)
3.331(2)
3.331(2)
2.116(7)
2.110(7)
2.131(8)
2.099(7)
2.115(8)
2.130(8)
2.095(8)
2.123(8)
2.101(8)
2.116(7)
2.120(8)
2.124(8)
80.5
90.3
174.1
74.1
81.9
167.8
73.9
171.3
87.8
84.3
79.0
172.2
3.382(4)
3.382(4)
3.382(4)
3.328(4)
3.328(4)
3.328(4)
3.384(4)
3.384(4)
3.384(4)
3.313(4)
3.313(4)
3.313(4)
2.13(1)
2.11(1)
2.14(2)
2.09(2)
2.12(1)
2.14(2)
2.09(2)
2.11(1)
2.12(1)
2.10(1)
2.12(1)
2.13(2)
80.7
90.1
174.5
74.9
82.4
168.7
74.6
172.0
88.2
84.6
79.5
173.4
,
3.142(1)–3.234(1) A and the coordination around tel-
lurium is a distorted trigonal bipyramid with an
AX3Y2E arrangement. In contrast the cations and an-
ions in the solvated salt form a tetrameric structural
unit with two different environments around tellurium.
One shows an octahedral AX3Y3E arrangement and the
other a five-coordinated AX3Y2E arrangement with one
vacant secondary bond position blocked by a phenyl
group [12].
The X-ray structures of 1–3, and 5 have shown that the
cation–anion interactions are significant in governing
the coordination geometry around tellurium and the
overall structural features. The primary bonding in the
Ph3Te+ cation in each salt is a trigonal AX3E pyramid.
The weak secondary interactions expand the coordina-
tion sphere. In (Ph3Te)2[MCl6] (M=Pt (1), Ir (2)) the
cation shows a trigonal bipyramidal AX3YE coordina-
tion with one primary TeꢀC bond and the shortest
The structure of (Ph3Te)(NO3)·HNO3 (5) consists of
two rows of Ph3Te+ cations that are bound together by
nitrate ions and nitric acid molecules, as shown in Fig.
5. The environment around tellurium is rather complex.
There are five Te···O contacts, two of which are due to
the nitric acid molecule and three due to two nitrate
ions, one oxygen atom acting as a bridge between two
Ph3Te+ cations. The distances involving nitric acid
,
oxygen atoms O(2) and O(3) [3.550(3) and 3.482(3) A,
respectively] are longer than those involving the nitrate
oxygen atoms O(1) and the bridging O(4) [3.083(3) and
3.087(3)–3.119(3), respectively]. Since the angles
ÚC(131)ꢀTe(1)···O(2),
ÚC(121)ꢀTe(1)···O(4),
and
ÚC(111)ꢀTe(1)···O(6) are approximately 180° (168.8,
174.3, and 167.9, respectively), the bonding arrange-
ment can best be described as AX3Y3Y%E. A similar
2
environment around tellurium has been observed for
(TeF3)2(SO4) [17].
4. Conclusions
In this paper we have reported the preparation of
four triphenyltelluronium salts (Ph3Te)n[MClx] (M=
Pt, Ir, Au; x=4, 6; n=1, 2) (1–4) in order to study the
effect of the size, geometry, and charge of a rather
bulky anion on the cation–anion interactions. The
recrystallization of (Ph3Te)2[PtCl4] (4) resulted in the
formation of K2[PtCl6] and (Ph3Te)(NO3)·HNO3 (5).
Fig. 5. The packing of the ions in the lattice of (Ph3Te)(NO3)(HNO3)
(5). The secondary bonding expands the coordination around tel-
lurium to an AX3Y3Y2% E arrangement. Hydrogen atoms have been
omitted for clarity.

56
R. Oilunkaniemi et al. / Journal of Organometallic Chemistry 640 (2001) 50–56
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and the two other TeꢀC bonds and the lone-pair occu-
pying the equatorial positions. Both compounds show
discrete Ph3Te···[MCl6]···TePh3 that are joined together
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2
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5. Supplementary material
Crystallographic information for compounds 1–3
and 5 has been deposited with the Cambridge Crystal-
lographic Data Centre, CCDC nos. 163383–163386.
Copies of this information may be obtained free of
charge from The Director, CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (Fax: +44-1223-336033;
e-mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
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Acknowledgements
Financial support from the Academy of Finland is
gratefully acknowledged.
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