Syntheses, structures and intermolecular interactions of tetraorganoammonium, -phosphonium and -stibonium dimethyl- and diphenyltetrahaloantimonates

Article abstract of DOI:10.1016/j.jorganchem.2010.02.016

The syntheses and spectroscopic (NMR, MS) investigations of the antimonates [Ph₄P]⁺[Me₂SbCl₄]^- (1), [Me₄Sb]⁺[Me₂SbCl₄]^- (2), [Et₄N]

Full text of DOI:10.1016/j.jorganchem.2010.02.016

Journal of Organometallic Chemistry 695 (2010) 1307–1313
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Syntheses, structures and intermolecular interactions of tetraorganoammonium,
-phosphonium and -stibonium dimethyl- and diphenyltetrahaloantimonates
a
a
b
b,
Hans J. Breunig a, , Tim Koehne , Ovidiu Moldovan , Ana Maria Preda , Anca Silvestru
,
*
*
Cristian Silvestru b, Richard A. Varga b, Luis F. Piedra-Garza c, Ulrich Kortz c
a Institut für Anorganische und Physikalische Chemie, Universität Bremen, D-28334 Bremen, Germany
b Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, RO-400028 Cluj-Napoca, Romania
c School of Engineering and Science, Jacobs University, P.O. Box 750561, D-28725 Bremen, Germany
a r t i c l e i n f o
a b s t r a c t
The syntheses and spectroscopic (NMR, MS) investigations of the antimonates [Ph4P]+[Me2SbCl4]ꢀ (1),
[Me4Sb]+[Me2SbCl4]ꢀ (2), [Et4N]+[Ph2SbCl4]ꢀ (3), [Bu4N]+[Ph2SbCl4]ꢀ (4), [Me4Sb]+[Ph2SbCl4]ꢀ (5),
[Et3MeSb]+[Ph2SbCl4]ꢀ (6), [Et4N]+[Ph2SbF4]ꢀ (7) and [Et4N]+[Ph2SbBr4]ꢀ (8) are reported. Halogen scram-
Article history:
Received 15 December 2009
Received in revised form 7 February 2010
Accepted 13 February 2010
Available online 17 February 2010
bling reactions of Et4NBr or Ph4EBr (E = P, Sb) wiꢀth R2SbCl3 (R = Me, Ph) produce mixtures of compounds
ꢀ
from which crystals of [Et4N]+[Ph2SbBr1.24Cl2.76
]
(9), [Et4N]+[Ph2SbBr2.92Cl1.08
]
(10) or [Ph4Sb]+[Me2Sb
Cl4]ꢀ (11) were isolated. The crystal and molecular structures of 1 and 3–11 are reported.
Ó 2010 Elsevier B.V. All rights reserved.
Keywords:
Diorganotetrahaloantimonates
NMR studies
X-ray diffraction
1. Introduction
data were interpreted in terms of the presence of [trans-R2SbX4]ꢀ
species (R = Me, Ph; X = F, Cl, Br) [5–7]. Crystallographic studies
for [HBipy]+[Ph2SbCl4]ꢀ [8] and [HPy]+[Ph2SbCl4]ꢀ [9] were
reported.
Salts consisting of the pyridinium ion, (C5H5NH)+, as cation and
diaryltetrachloro antimonate anions, [R2SbCl4]ꢀ, have been known
since 1920 [1,2]. They were prepared by reactions of pyridine
hydrochloride with diarylantimony(V) trichlorides and were
widely used as intermediates for the synthesis and purification of
stibinic acids R2Sb(O)OH [3,4]. Later also dialkyl- and diaryltetra-
chloroantimonates with cations like aryldiazonium, tetraalkylam-
monium or tetraphenylarsonium ions were synthesized by
combining the corresponding onium chloride with a diorganoanti-
Compounds with lower melting points, chemically related to
onium diorganotetrahaloantimonates, were used as environmen-
tally friendly ionic solvents for various organic reactions [10]. Also
onium diorganotetrahaloantimonates are candidates for applica-
tions as ionic liquids because the introduction of longer alkyl sub-
stituents both on the cations and the anions may decrease the
lattice energy and result in the formation of low melting salts. An-
other possible application for the permethylated salt [Me4Sb]+[Me2
SbCl4]ꢀ (2) is the use as standard for the analyses of methylantimo-
ny compounds formed by biomethylation of antimony in the envi-
ronment [11].
mony(V) trichloride [2]. Salts with the mixed-halide [Ph2SbBrn
ꢀ
Cl4ꢀn
]
anion were obtained by addition of Et4NBr or other onium
bromides to Ph2SbCl3 [2,5–7]. The only known diorganotetrabro-
moantimonate, was prepared from
[Ph4As]+[Ph2SbBr4]ꢀ
Ph2SbCl3ꢁH2O or Ph2Sb(O)OH, HBr and [Ph4As]X (X = Cl or Br) [7].
Diorganotetraiodoantimonates are unknown, but diorganotetraflu-
oroantimonates were described frequently [2]. The fluoro deriva-
tives M[Ph2SbF4] (M = H, Na, K) were obtained by reactions of
C6H6 with SbF5 and water, NaOH or KOH. [Ph4As]+[Ph2SbF4]ꢀ was
formed from Ph2SbCl3ꢁH2O, Ph4AsCl and HF [7]. Structural studies
of diorganotetrahaloantimonates were carried out using
Mössbauer, infrared and Raman spectroscopies and the resulting
Searching for diorganoantimony(V) reagents that can be used
for the syntheses of organoantimony polyoxometalates [12] in
aqueous conditions we became interested in the chemistry of
diorganoantimony(V) trihalides and onium diorganotetrahaloan-
timonates. Our previous related studies had focused on dipheny-
lantimony tribromide and onium organoantimonates(III) [13–15].
We report here the syntheses and spectroscopic (NMR, MS)
investigation of the several tetrahaloantimonates as well as the
crystal and molecular structures of [Ph4P]+[Me2SbCl4]ꢀ (1),
[Et4N]+[Ph2SbCl4]ꢀ (3), [Bu4N]+[Ph2SbCl4]ꢀ (4), [Me4Sb]+[Ph2Sb
* Corresponding authors. Tel.: +49 421 218 63150; fax: +49 421 218 62809 (H.J.
Breunig), tel.: +40 264 593833; fax: +40 264 590818 (A. Silvestru).
E-mail addresses: hbreunig@uni-bremen.de (H.J. Breunig), ancas@chem.ubb-
cluj.ro (A. Silvestru).
Cl4]ꢀ (5), [Et3MeSb]+[Ph2SbCl4]ꢀ (6), [Et4N]+[Ph2SbF4]ꢀ (7), [Et4N]+
ꢀ
[Ph2SbBr4]ꢀ (8), [Et4N]+[Ph2SbBr1.24Cl2.76
]
(9), [Et4N]+[Ph2SbBr2.92
ꢀ
Cl1.08
]
(10) and [Ph4Sb]+[Me2SbCl4]ꢀ (11).
0022-328X/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2010.02.016

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H.J. Breunig et al. / Journal of Organometallic Chemistry 695 (2010) 1307–1313
2.2. Crystal and molecular structures
2. Results and discussion
Single crystals suitable for X-ray diffraction studies were ob-
tained from acetonitrile solutions by slow evaporation, at room
temperature, in an open atmosphere, for compounds 1 and 3–11.
As representative examples the structures of1, 4, 5, 7 and 8, show-
ing both the cation and the anion, are depicted in Figs. 1–3. In the
mixed-halogen compounds, i.e. 9 and 10, there was disorder
involving the bromine or chlorine atoms. The best solution was ob-
tained with Br/Cl occupancy of 0.31/0.69 for 9 and 0.73/0.27 for 10,
respectively (see also Supplementary material). Disorder phenom-
ena were also observed for the [Et4N]+ cation in the corresponding
salts, i.e. 3 and 7–10.
All the salts are composed of tetrahedral onium cations and
octahedral anions. In all cases, regardless the nature of the halogen,
the methyl or phenyl groups in the [R2SbX4]ꢀ anions are placed in
trans positions. This is consistent with the previous reports on re-
lated salts based on Raman, IR and Mössbauer data and also with
the results of our NMR investigations in solution.
The major difference in the anions containing phenyl groups is
concerned to the relative orientation of the two aromatic rings. In
all compounds the phenyl rings are basically bisecting the X–Sb–X
angles of the square planar SbX4 plane. For compound 5 (Fig. 1) the
phenyl rings are coplanar, while in compounds 4 and 7 (Fig. 2) they
are slightly deviated from coplanarity (dihedral angles of 8.3° and
11.3°, respectively). Compound 6 contains three independent an-
ions in the unit cell: two of them, i.e. anions 6b and 6c, contain
coplanar phenyl rings, while in anion 6a a slight deviation from
coplanarity (dihedral angle of 7.2°) was observed. By contrast, for
compounds 3, 8 (Fig. 3), 9 and 10, which contain the [Et4N]+ coun-
ter-cation, the phenyl rings are orthogonal.
2.1. Preparation and spectroscopic characterization
The syntheses of the salts 1–7 were performed by reactions of
dimethyl- or diphenylantimonytrichloride with R04NCl (R0 = Et,
Bu), Ph4PCl, Me4SbI or Et3MeSbI in methanol or a mixture of meth-
anol and hydrochloric acid. The reactions between R04ECl and
R2SbCl3 are straight forward with the transfer of the chloride ion
from the ammonium or phosphonium compound to the Lewis
acidic diorganoantimony trichloride (Scheme 1):
The reactions between stibonium iodides and R2SbCl3 combine
redox processes with formation of iodine or triiodide, as suggested
by the brown color of the reaction mixture, and chloride transfer,
as indicated by single-crystal X-ray diffraction studies. The iodine
can further react with the stibonium iodide with formation of a tri-
iodide (Scheme 2).
By contrast, the reactions between onium bromides and R2SbCl3
lead to mixtures of chloro/bromo derivatives due to scrambling of
halogens. The ES MS (negative) data are consistent with this behav-
ior, several anions being observed, e.g. [Ph2SbBr2Cl2ꢀ],
[Ph2SbBrCl3ꢀ] and [Ph2SbCl4ꢀ] for the crude product isolated from
the reaction of Et4NBr with Ph2SbCl3ꢁH2O. From such mixtures of
ꢀ
compounds crystals of [Et4N]+[Ph2SbBr1.24Cl2.76
]
(9), [Et4N]+[Ph2
SbBr2.92Cl1.08]
ꢀ (10) or [Ph4Sb]+[Me2SbCl4]ꢀ (11) were isolated. At-
tempts to complete the exchange of halogen by reacting the crude
ꢀ
[Et4N]+[Ph2SbBrnCl4ꢀn
]
(n = 0–4) with NaBr have failed. Pure
[Et4N]+[Ph2SbBr4]ꢀ (8) was obtained by reacting Et4NBr with
Ph2SbBr3. However, the full exchange of halogen was achieved
when [Et4N]+[Ph2SbCl4]ꢀ (3) was reacted with NaF and the tetraflu-
oroantimonate [Et4N]+[Ph2SbF4]ꢀ (7) was obtained.
The Sb–F bond lengths in 7 [1.957(2), 1.960(3) Å] are slightly
shorter than in the monomeric Me3SbF2 [1.993(4), 2.004(4) Å]
[16]. In the tetrachloroantimonates described here the Sb–Cl bond
distances are in the range 2.456(1)–2.503(3) Å, being of intermedi-
ate length between terminal and bridging antimony–halogen
bonds in the dimers (Ph2SbCl3)2 [2.346(4), 2.388(4) Å vs.
2.620(4), 2.839(4) Å] [17] or (Me2SbCl3)2 [2.353(2), 2.356(2) Å vs.
2.798(2), 2.801(2) Å] [18] and of same magnitude as found for
the equatorial Sb–Cl bonds in trans to each other in the monomer
Ph2SbCl3ꢁH2O [2.462(2) Å] [19]. The Sb–Br bonds in 8 [2.646(1) Å]
are larger than the Sb–Br bonds in the adduct Ph2SbBr3ꢁMeCN
[2.519(2), 2.605(1) Å] [19] or the terminal Sb–Br bonds [2.478(3),
2.557(3) Å] in the polymeric association found in the crystal of
Ph2SbBr3 [20], but compare well with the shorter bridging anti-
mony–bromine bond distance [2.673(3) Å] in the latter compound.
The values of the Sb–C bond lengths in the [R2SbX4]ꢀ anions
(see also Supplementary material) are comparable with the values
found in the related starting materials, i.e. (Me2SbCl3)2 [2.1316(2),
2.1349(2) Å] [18], (Ph2SbCl3)2 [2.125(9) Å] [17], Ph2SbCl3ꢁH2O
[2.1218(8) Å] [19] or Ph2SbBr3 [2.149(12) Å] [20]. The same consid-
erations apply for the lengths of the Sb–C bonds in the cations
The pure tetrahaloantimonates 1–8 were isolated as air stable,
colorless crystalline solids. Mass spectra obtained with the electro-
spray ionization technique (ESI) show the cation and the anion for
these compounds. Consistent with their ionic nature, the majority
of the compounds were soluble in DMSO. However, [Bu4N]+[Ph2
SbCl4]ꢀ (4) was found to be also soluble in CHCl3, a behavior sug-
gesting that increase in the length of the alkyl groups on nitrogen
might increase considerably the solubility of such ionic compounds
in organic solvents.
The 1H and 13C NMR spectra of compounds 1–8 show the ex-
pected resonances both for the cations and anions. The presence
of one set of signals suggests the equivalence, in solution, of the or-
ganic groups attached to antimony in the [R2SbCl4]ꢀ anions.
[Me4Sb]+ in 5 [2.097(3), 2.098(3) Å], [Et3MeSb]+ in
2.065(19)–2.150(19) Å] or [Ph4Sb]+ in 11 [2.104(5) Å], which
6 [range
Scheme 1.
Scheme 2.

H.J. Breunig et al. / Journal of Organometallic Chemistry 695 (2010) 1307–1313
1309
Fig. 1. ORTEP representation at 30% probability and atom numbering scheme for 5
[symmetry equivalent position (0.5 ꢀ x, 1.5 ꢀ y, 2 ꢀ z) is given by ‘‘a” for the anion,
and (1 ꢀ x, y, 1.5 ꢀ z) by ‘‘b” for the cation; hydrogen atoms are omitted for clarity].
Selected distances (Å) and angles (°): Sb(1)–C(1) 2.136(3), Sb(1)–Cl(1) 2.4720(7),
Sb(1)–Cl(2) 2.4710(7); C(1)–Sb(1)–C(1a) 180.00(6), C(1)–Sb(1)–Cl(1) 90.50(7),
C(1)–Sb(1)–Cl(2) 89.91(7), C(1)–Sb(1)–Cl(1a) 89.50(7), C(1)–Sb(1)–Cl(2a) 90.09(7),
C(1a)–Sb(1)–Cl(1) 89.50(7), C(1a)–Sb(1)–Cl(2) 90.09(7), C(1a)–Sb(1)–Cl(1a)
90.50(7), C(1a)–Sb(1)–Cl(2a) 89.91(7), Cl(1)–Sb(1)–Cl(1a) 180.00(3), Cl(2)–Sb(1)–
Cl(2a) 180.0, Cl(1)–Sb(1)–Cl(2) 90.20(2), Cl(1)–Sb(1)–Cl(2a) 89.80(2), Cl(1a)–Sb(1)–
Cl(2a) 90.20(2), Cl(1a)–Sb(1)–Cl(2) 89.80(2).
Fig. 3. ORTEP representation at 30% probability and atom numbering scheme for 8
[symmetry equivalent positions (x, y, 0.5 ꢀ z), (1 ꢀ x, y, 0.5 ꢀ z) and (1 ꢀ x, y, z) are
given by ‘‘a”, ‘‘b” and ‘‘c” for the anion, and (1 ꢀ x, ꢀy, 1 ꢀ z) and (x, ꢀy, 1 ꢀ z) by ‘‘d”
and ‘‘e” for the cation; hydrogen atoms are omitted for clarity]. Selected distances
(Å) and angles (°):Sb(1)–C(1) 2.145(9), Sb(1)–C(5) 2.152(11), Sb(1)–Br(1)
2.6462(12), C(1)–Sb(1)–C(5) 180.000(2), C(1)–Sb(1)–Br(1) 89.898(18), C(5)–Sb(1)–
Br(1) 90.102(18), Br(1)–Sb(1)–Br(1b) 179.80(4), Br(1)–Sb(1)–Br(1a) 89.81(5), Br(1)–
Sb(1)–Br(1c) 90.19(5).
compare well with those observed in Me4SbI [2.043(2), 2.070(1) Å]
[21] and Ph4SbBr [2.092(9)–2.151(9) Å] [22].
Interesting aspects emerge when the packing of the ions is in-
spected in the crystals of compounds containing tetraorganos-
tibonium cations. Weak cation–anion interactions are observed
in the crystals of 5 and 6, resulting in different associations. In
5 all the chlorine atoms of a [Ph2SbCl4]ꢀ anion are involved in
interactions with the metal center from four different [Me4Sb]+
P
cations [Sb(2)ꢁꢁꢁCl(1) 3.66, Sb(2)ꢁꢁꢁCl(2) 3.89 Å; cf.
rvdW(Sb,Cl)
ca. 4.0 Å] [23] thus resulting in a 3D architecture (Fig. 4). In addi-
tion, C–Hmethylꢁꢁꢁ
p
(Phcentroid) contacts [2.89 Å] between anions
and cations are also present. The vectors of the SbꢁꢁꢁCl interactions
are directed towards the capping positions of the tetrahedral SbC4
core of the cation. By contrast, in the crystal of 6 only one of the
three independent anions, i.e. 6c, is involved in two SbꢁꢁꢁCl inter-
actions [Sb(5d)ꢁꢁꢁCl(8) 3.93 Å] through halogen atoms placed in
trans position, thus leading to discrete cation–anion–cation units
(see Supplementary material). In [Ph4Sb]+[Me2SbCl4]ꢀ (11) where
the cation is sterically protected close cation–anion contacts
through SbꢁꢁꢁCl interactions were not observed. No significant dis-
tortions were noted in the cation coordination sphere of com-
pounds 5 [Sb–C 2.097(3)/2.098(3) Å; C–Sb–C range 107.3(2)–
Fig. 2. ORTEP representation at 30% probability and atom numbering scheme for 7
(hydrogen atoms are omitted for clarity). Selected distances (Å) and angles (°):
Sb(1)–C(1) 2.114(4), Sb(1)–C(7) 2.116(4), Sb(1)–F(1) 1.960(2), Sb(1)–F(2) 1.960(3);
Sb(1)–F(3) 1.957(2), Sb(1)–F(4) 1.960(3), C(1)–Sb(1)–C(7) 177.76(14), C(1)–Sb(1)–
F(1) 90.27(13), C(1)–Sb(1)–Fl(2) 90.42(13), C(1)–Sb(1)–F(3) 90.24(13), C(1)–Sb(1)–
F(4) 88.70(13), C(7)–Sb(1)–F(1) 90.77(13), C(7)–Sb(1)–F(2) 91.56(13), C(7)–Sb(1)–
F(3) 88.74(13), C(7)–Sb(1)–F(4) 89.31(13), F(1)–Sb(1)–F(3) 179.22(13), F(2)–Sb(1)–
F(4) 178.98(12), F(1)–Sb(1)–F(2) 90.13(15), F(1)–Sb(1)–F(4) 90.39(14), F(2)–Sb(1)–
F(3) 89.28(15), F(3)–Sb(1)–F(4) 90.21(14).
111.4(1)°],
6 [Sb–C range 2.065(19)–2.150(19)/2.07(2)–2.115
(19) Å; C–Sb–C range 105.6(6)–112.1(7)/105.3(15)–114.3(9)°]
and 11 [Sb–C 2.104(5) Å; C–Sb–C range 103.8(3)–112.4(1)°].

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H.J. Breunig et al. / Journal of Organometallic Chemistry 695 (2010) 1307–1313
Fig. 4. View of a fragment of the 3D architecture based on antimony–chlorine and C–Hmethylꢁꢁꢁ
p (Phcentroid) contacts between anions and cations in the crystal of 5 [only
hydrogens involved in anion–cation C–Hmethylꢁꢁꢁ
p contacts are shown].
acetonitrile by slow evaporation in the open atmosphere gave 1
as colorless crystals. Yield: 1.9 g (78%). M.p. 225 °C. Anal. Calc. for
C26H26Cl4PSb: C, 49.33; H, 4.14. Found: C, 48.33; H, 4.52%. 1H
NMR (200 MHz, DMSO-d6): d 2.82s (6H, SbCH3), 7.77 m (16H,
PC6H5-meta + ortho), 7.97 m (4H, PC6H5-para). 13C NMR
3. Conclusions
The onium diorganotetrafluoro-, -chloro- and -bromoantimo-
nates reported here represent a large family of easily accessible,
stable organoantimony compounds. The ionic nature and the al-
most uniform structure of the tetrahedral cations and the octahe-
dral antimony anions with the organic groups in trans positions
are clearly demonstrated. Applications of this class of compounds
in organoantimony syntheses, e.g. the preparation of stibinic acids
have a long tradition. The antimonates are certainly useful for the
formation of salts with a variety of inorganic or organic cations.
Other potential applications include, among others, the use as or-
ganic–inorganic materials, ionic solvents or analytical standards
for antimony analyses or antimony-containing medicines.
1
(50.3 MHz, DMSO-d6): d 61.24 (SbCH3), 117.59d (PC6H5-ipso, JPC
89.2 Hz), 130.36d (PC6H5-meta, 3JPC 12.8 Hz), 134.47d (PC6H5-ortho,
4
2JPC 10.5 Hz), 135.24d (PC6H5-para, JPC 2.7 Hz). 31P NMR
(81.0 MHz, DMSO-d6): d 23.7. MS (ESI, CH3CN), m/z (%), pos.: 339
(100) [Ph4P+]; neg.: 292 (72) [Me2SbCl4ꢀ], 242 (100) [MeSbCl3ꢀ].
4.3. Synthesis of [Me4Sb]+[Me2SbCl4]ꢀ (2)
A solution of Me4SbI (0.5 g, 1.6 mmol) in 20 ml methanol was
added dropwise to Me2SbCl3 (0.42 g, 1.6 mmol) in 50 ml methanol
and the mixture was stirred for 1 h. The color changed to yellow
and a white precipitate formed. After filtration the solid was solved
in CH3CN. Slow evaporation of the solvent in the open atmosphere
gave crystals of 2. Yield: 0.55 g (71%). M.p. 95 °C. 1H NMR
(200 MHz, DMSO-d6): d 1.61s (6H, SbCH3), 1.75s (12H, SbCH3).
MS (ESI, CH3CN), m/z (%), pos.: 181 (100) [Me4Sb+]; neg.: 292
(30) [Me2SbCl4ꢀ], 242 (100) [MeSbCl3ꢀ].
4. Experimental
4.1. Materials and procedures
The starting materials such as Et4NCl, Et4NBr, Bu4NClꢁH2O,
Ph4PCl, Ph4PBr, NaF and NaBr were commercially available.
Me2SbCl3 [24], Ph2SbCl3 [25], Ph2SbCl3ꢁH2O [19], Ph2SbBr3 [13],
Me4SbI [26], Et3MeSbI [26], Ph4SbBr [21] were prepared according
to published methods. Room-temperature 1H, 13C and 19F spectra
were recorded in DMSO-d6 or CDCl3 with BRUKER DPX 200 or Bru-
ker Avance DRX 300 instruments. The chemical shifts are reported
in ppm relative to the residual peak of the solvent (ref. CHCl3: 1H
7.26, 13C 77.0 ppm; DMSO-d5: 1H 2.50, 13C 39.43 ppm) and relative
to CFCl3 for 1H, 13C and 19F NMR spectra, respectively. Mass spectra
were recorded with a FINNIGAN MAT 8200 spectrometer.
4.4. Synthesis of [Et4N]+[Ph2SbCl4]ꢀ (3)
A solution of Et4NCl (1.20 g, 7.3 mmol) in 30 ml methanol was
added dropwise to a stirred solution of Ph2SbCl3ꢁH2O (2.92 g,
7.3 mmol) in 20 ml methanol at room temperature. After 24 h
of stirring the solvent was removed in vacuum and a white pow-
der was isolated. The title compound was recrystallized from ace-
tonitrile to give a colorless microcrystalline product. Yield: 3.6 g
(90%). M.p. 268–269 °C. 1H NMR (200 MHz, DMSO-d6): d 1.12 m
4.2. Synthesis of [Ph4P]+[Me2SbCl4]ꢀ (1)
3
(12H, NCH2CH3), 3.15q (8H, NCH2CH3, JHH 7.1 Hz), 7.42 m (6H,
3
A solution of Me2SbCl3 (1.0 g, 3.9 mmol) in 50 ml methanol was
added dropwise to Ph4PCl (1.45 g, 4.2 mmol) in 30 ml methanol
and a white solid is formed. Filtration and crystallization from
SbC6H5-meta + para), 8.22d (4H, SbC6H5-ortho, JHH 7.2 Hz). 13C
NMR (50.3 MHz, DMSO-d6):
d
6.96 (NCH2CH3), 51.28 m
(NCH2CH3), 127.38 (SbC6H5-meta), 128.87 (SbC6H5-para), 130.41

H.J. Breunig et al. / Journal of Organometallic Chemistry 695 (2010) 1307–1313
1311
(SbC6H5-ortho), 167.34 (SbC6H5-ipso). MS (ESI, CH3CN), m/z (%),
49.82; H, 6.27. Found: C, 49.72; H, 6.78%. 1H NMR (300 MHz,
DMSO-d6): d 1.11 m (12H, NCH2CH3), 3.14q (8H, NCH2CH3, JHH
pos.: 130 (100) [Et4N+]; neg.: 417 (100) [Ph2SbCl4ꢀ].
3
7.2 Hz), 7.38 m (6H, SbC6H5-meta + para), 7.81 m (4H, SbC6H5-
4.5. Synthesis of [Bu4N]+[Ph2SbCl4]ꢀ (4)
ortho). 13C NMR (75.4 MHz, DMSO-d6):
d
6.90 (NCH2CH3),
51.30 m (NCH2CH3), 127.63 (SbC6H5-meta), 128.75 (SbC6H5-para),
3
2
To a solution of Bu4NClꢁH2O (0.89 g, 3.0 mmol) in 50 ml metha-
nol was added dropwise, under stirring, a solution of Ph2SbCl3ꢁH2O
(1.20 g, 3.0 mmol) in 50 ml methanol, at room temperature. The re-
sulted suspension was stirred for 1 h, then filtered and the solid
was washed with 5 ml methanol. The solid was dissolved in
20 ml acetonitrile and the solution, left in open atmosphere, depos-
ited within 24 h air stable, colorless crystals which were filtered
off. Yield: 1.94 g (98%). M.p. 169 °C. Anal. Calc. for C28H46Cl4NSb:
C, 50.94; H, 7.02. Found: C, 51.11; H, 6.96%. 1H NMR (200 MHz,
133.02qv (SbC6H5-ortho, JFC 2.0 Hz), 149.92 (SbC6H5-ipso, JFC
37.0 Hz). 19F NMR (282.4 MHz, DMSO-d6): d ꢀ103.2. MS (ESI,
CH3CN), m/z (%), pos.: 611 (30) [M+Et4N+], 130 (100) [Et4N+];
neg.: 351 (100) [Ph2SbF4ꢀ].
4.9. Synthesis of [Et4N]+[Ph2SbBr4]ꢀ (8)
A solution of Et4NBr (0.09 g, 0.44 mmol) in 15 ml acetonitrile
was added dropwise to a stirred solution of Ph2SbBr3 (0.23 g,
0.44 mmol) in 15 ml acetonitrile. After 24 h of stirring at room
temperature the solvent was removed in vacuum and a white pow-
der was isolated. The title compound was recrystallized from ace-
tonitrile to give a colorless microcrystalline product. Yield: 0.25 g
(88%). M.p. 245–247 °C. 1H NMR (200 MHz, DMSO-d6): d 1.15 m
3
CDCl3): d 0.85t [12H, NCH2(CH2)2CH3, JHH 7.0 Hz], 1.89 m [16H,
3
NCH2(CH2)2CH3], 2.84t [8H, NCH2(CH2)2CH3, JHH 8.0 Hz], 7.32 m
3
(6H, SbC6H5-meta + para), 8.39d (4H, SbC6H5-ortho, JHH 8.0 Hz).
13C NMR (50.3 MHz, DMSO-d6): d 13.60 (Cd), 19.51 (C ), 23.82
c
(Cb), 58.57 (C ), 127.44 (SbC6H5-meta), 128.75 (SbC6H5-para),
a
3
131.04 (SbC6H5-ortho), 167.89 (SbC6H5-ipso). MS (ESI, CH3CN), m/
(12H, NCH2CH3), 3.20q (8H, NCH2CH3, JHH 7.3 Hz), 7.45 m (6H,
z (%), pos.: 242 (100) [Bu4N+]; neg.: 417 (100) [Ph2SbCl4ꢀ].
SbC6H5-meta + para), 8.06d (4H, SbC6H5-ortho, JHH 7.4 Hz). 13C
3
NMR (50.3 MHz, DMSO-d6): d 7.02 (NCH2CH3), 51.29 m (NCH2CH3),
128.10 (SbC6H5-meta), 129.28 (SbC6H5-para), 129.85 (SbC6H5-
ortho), 161.59 (SbC6H5-ipso). MS (ESI, CH3CN), m/z (%), pos.: 130
(100) [Et4N+]; neg.: 595 (100) [Ph2SbBr4ꢀ].
4.6. Synthesis of [Me4Sb]+[Ph2SbCl4]ꢀ (5)
A suspension of Me4SbI (1.43 g, 4.6 mmol) in 30 ml methanol
was added dropwise to
a
solution of Ph2SbCl3ꢁH2O (1.85 g,
4.6 mmol) in 50 ml of a 1:1 mixture of HCl (37% in water) and
methanol and the mixture was stirred for 2 h. The color changed
from yellow to brown and a white solid precipitated. The solid
was filtered off and then solved in CH3CN. The solution, left in
the open atmosphere at room temperature, deposited air stable,
colorless crystals of 5. Yield: 1.85 g (72%). M.p. 247 °C. Anal. Calc.
for C16H22Cl4Sb2: C, 32.05; H, 3.70. Found: C, 32.26; H, 4.33%. 1H
NMR (200 MHz, DMSO-d6): d 1.49s (12H, SbCH3), 7.39 m (6H,
4.10. Reaction of Et4NBr and Ph2SbCl3ꢁH2O
A solution of Et4NBr (0.17 g, 0.82 mmol) in 20 ml methanol was
added dropwise to a solution of Ph2SbCl3ꢁH2O (0.33 g, 0.82 mmol)
in 20 ml methanol, under stirring, at room temperature. After
24 h the solvent was removed in vacuum and a white powder
was obtained. The product was recrystallized from acetonitrile to
give colorless crystals (0.27 g, 56%). Anal. Calc. for C20H30BrCl3NSb:
C, 40.54; H, 5.10. Found: C, 40.38; H, 5.82%. MS (ESI, CH3CN), m/z
(%), pos.: 130 (100) [Et4N+]; neg.: 595 (80) [Ph2SbBr4ꢀ], 550 (100)
[Ph2SbBr3Clꢀ], 506 (24) [Ph2SbBr2Cl2ꢀ], 461 (2) [Ph2SbBrCl3ꢀ].
3
SbC6H5-meta + para), 8.21d (4H, SbC6H5-ortho, JHH 7.2 Hz). 13C
NMR (50.3 MHz, DMSO-d6): d 2.23 (SbCH3), 127.37 (SbC6H5-meta),
128.86 (SbC6H5-para), 130.42 (SbC6H5-ortho), 167.34 (SbC6H5-ipso).
MS (ESI, CH3CN), m/z (%), pos.: 181 (100) [Me4Sb+]; neg.: 417 (100)
[Ph2SbCl4ꢀ].
4.11. Reaction of Ph4PBr and Ph2SbCl3ꢁH2O
4.7. Synthesis of [Et3MeSb]+[Ph2SbCl4]ꢀ (6)
A solution of Ph4PBr (2.2 g, 5.2 mmol) in 30 ml methanol was
added dropwise to a solution of Ph2SbCl3ꢁH2O (2.0 g, 5.0 mmol)
in 50 ml methanol, under stirring, at room temperature. The reac-
tion mixture was stirred for 2 h, then the white solid formed was
filtered off and solved in acetonitrile. Exposure of the solution to
the open atmosphere gave white crystals (1.61 g, 41%). MS
(ESI, CH3CN), m/z (%), pos.: 339 (100) [Ph4P+]; neg.: 506 (8)
[Ph2SbBr2Cl2ꢀ], 461 (32) [Ph2SbBrCl3ꢀ], 417 (100) [Ph2SbCl4ꢀ].
A solution of Et3MeSbI (0.87 g, 2.5 mmol) in 10 ml methanol
was added dropwise to Ph2SbCl3ꢁH2O (1.0 g, 2.5 mmol) in 15 ml
of methanol and the mixture was stirred for 1 h. The color changed
from yellow to dark brown and a light yellow precipitate formed.
The solid was filtered off and then solved in CH3CN. Slow evapora-
tion of the solvent in the open atmosphere gave colorless crystals
of 6. Yield: 0.8 g (43%). M.p. 152 °C. 1H NMR (200 MHz, DMSO-
3
d6): d 1.30t (9H, SbCH2CH3, JHH 7.9 Hz), 1.38s (3H, SbCH3), 2.17q
4.12. Reaction of Ph4SbBr and Me2SbCl3
3
(6H, SbCH2CH3, JHH 7.9 Hz), 7.41 m (6H, SbC6H5-meta + para),
8.22 m (4H, SbC6H5-ortho). 13C NMR (50.3 MHz, DMSO-d6): d
ꢀ4.63 (SbCH3), 9.09 (SbCH2CH3), 11.83 (SbCH2CH3), 127.34
(SbC6H5-meta), 128.83 (SbC6H5-para), 130.39 (SbC6H5-ortho),
167.32 (SbC6H5-ipso). MS (ESI, CH3CN), m/z (%), pos.: 223 (100) [Et3-
MeSb+]; neg.: 417 (100) [Ph2SbCl4ꢀ].
A solution of Ph4SbBr (0.4 g, 0.7 mmol) in 25 ml methanol was
added dropwise to Me2SbCl3 (0.2 g, 0.7 mmol) in 30 ml methanol.
The mixture was stirred for 1 h at room temperature and the sol-
vent was removed in vacuum. The remaining solid was solved in
acetonitrile and the solution was exposed to the atmosphere to
produce white crystals which were separated by filtration
(0.52 g, 37%).
4.8. Synthesis of [Et4N]+[Ph2SbF4]ꢀ (7)
A solution of NaF (0.3 g, 7.1 mmol) in 20 ml acetonitrile was
added dropwise to a stirred solution of [Et4N]+[Ph2SbCl4]ꢀ (3)
(0.5 g, 0.9 mmol) in 20 ml acetonitrile at room temperature. After
24 h of stirring the solvent was removed in vacuum and a white
powder was isolated. The title compound was recrystallized from
acetonitrile to give a colorless microcrystalline product. Yield:
0.34 g (78%). M.p. 151–153 °C. Anal. Calc. for C20H30F4NSb: C,
4.13. Reaction of Ph4SbBr and Ph2SbCl3
A solution of Ph4SbBr (0.5 g, 0.9 mmol) in 20 ml methanol was
added dropwise to Ph2SbCl3 (0.37 g, 0.9 mmol) in 30 ml methanol.
The mixture was stirred for 1 h at room temperature and the sol-
vent was removed in vacuum. The remaining solid was solved in
acetonitrile and the solution was exposed to the atmosphere to

1312
H.J. Breunig et al. / Journal of Organometallic Chemistry 695 (2010) 1307–1313
Table 1
X-ray crystal data and structure refinement for compounds 1, 3–6.
1
3
4
5
6
Empirical formula
Formula weight
T (K)
C26H26Cl4PSb
632.99
297(2)
C20H10Cl4NSb
527.84
297(2)
C28H46Cl4NSb
660.21
173(2)
C16H22Cl4Sb2
599.64
173(2)
C19H28Cl4Sb2
641.71
173(2)
k (Å)
0.71073
Tetragonal
P4/n
0.71073
Monoclinic
C2/c
0.71073
Monoclinic
P21/n
0.71073
Monoclinic
C2/c
0.71073
Monoclinic
P21/c
Crystal system
Space group
Unit cell dimension
a (Å)
b (Å)
c (Å)
13.2796(19)
13.2796(19)
7.601(2)
90.00
90.00
90.00
1340.4(4)
2
1.568
1.501
632
9.780(3)
13.863(5)
17.770(6)
90
92.732(6)
90
2406.6(14)
4
1.457
16.6892(7)
9.2874(3)
20.6957(8)
90
103.326(3)
90
3121.4(2)
4
1.405
11.8797(11)
13.5320(11)
13.3885(13)
90
94.196(12)
90
2146.5(3)
4
1.856
7.903(3)
20.699(9)
29.369(17)
90
94.04(4)
90
4792(4)
8
1.779
a
(°)
b (°)
(°)
c
Volume (Å3)
Z
Dcalc (g cmꢀ3
)
Absorption coefficient (mmꢀ1
F(0 0 0)
)
1.594
1024
1.243
1360
3.018
1152
2.702
2496
Crystal size (mm)
h Range for data collection (°)
Reflections collected
0.31 ꢂ 0.24 ꢂ 0.24
2.17–24.99
9336
0.28 ꢂ 0.22 ꢂ 0.17
2.29–25.00
11 419
0.29 ꢂ 0.08 ꢂ 0.06
3.41–26.37
33 158
0.60 ꢂ 0.50 ꢂ 0.50
2.68–25.50
4760
0.60 ꢂ 0.60 ꢂ 0.15
2.58–5.00
11 050
Independent reflections
Data/restraints/parameters
1187 [Rint = 0.0434]
1187/0/75
Multi-scan [29]
1.201
2120 [Rint = 0.0474]
2120/0/140
Multi-scan [29]
1.143
6362 [Rint = 0.1120]
6362/0/307
Multi-scan [29]
1.002
1995 [Rint = 0.0339]
1995/0/105
DIFABS [30]
1.186
8348 [Rint = 0.0786]
8348/0/482
DIFABS [30]
1.081
Absorption correction
GOF on F2
Final R indicesa
R1
wR2
0.0336
0.0767
0.0379
0.0979
0.0453
0.0817
0.0195
0.0492
0.0803
0.2022
R indices (all data)
R1
0.0369
0.0398
0.0954
0.0200
0.1057
wR2
0.0785
0.353 and ꢀ0.787
0.0993
0.686 and ꢀ0.922
0.0989
0.823 and ꢀ0.750
0.0494
0.494 and ꢀ0.382
0.2197
1.577 and ꢀ1.575
Largest difference peak and hole (e Åꢀ3
)
a
I > 2r(I).
Table 2
X-ray crystal data and structure refinement for compounds 7–11.
7
8
9
10
11
Empirical formula
Formula weight
T (K)
C20H30F4NSb
482.20
297(2)
C20H10Br4NSb
705.68
297(2)
C20H10Br1.24Cl2.76NSb
582.97
297(2)
C20H10Br2.92Cl1.08NSb
657.64
297(2)
C26H26Cl4Sb2
723.77
173(2)
k (Å)
0.71073
Monoclinic
P21/n
0.71073
Orthorhombic
Cmcm
0.71073
Orthorhombic
Cmcm
0.71073
Orthorhombic
Cmcm
0.71073
Tetragonal
P4/n
Crystal system
Space group
Unit cell dimension
a (Å)
b (Å)
c (Å)
7.1770(13)
32.264(6)
9.1454(17)
90.00
99.344(3)
90.00
2089.6(7)
4
1.533
9.960(5)
14.134(8)
18.142(10)
90
90
90
2554(2)
4
1.835
7.341
1312
9.826(3)
13.882(4)
17.853(5)
90
90
90
2435.3(11)
4
1.590
3.474
1114
9.8945(19)
14.006(3)
17.988(4)
90
90
90
2492.8(9)
4
1.673
4.904
1186
13.349(3)
13.349(3)
7.919(3)
90
90
90
1411.1(7)
2
1.703
a
(°)
b (°)
(°)
c
Volume (Å3)
Z
Dcalc (g cmꢀ3
)
Absorption coefficient (mmꢀ1
F(000)
)
1.358
976
2.306
704
Crystal size (mm)
h Range for data collection (°)
Reflections collected
0.51 ꢂ 0.44 ꢂ 0.28
1.26–25.00
19 810
0.35 ꢂ 0.30 ꢂ 0.25
2.25–24.99
8999
0.42 ꢂ 0.31 ꢂ 0.17
2.28 to 25.00
8648
0.33 ꢂ 0.25 ꢂ 0.16
3.12 to 25.00
8821
0.42 ꢂ 0.27 ꢂ 0.22
2.16 to 25.00
6504
Independent reflections
Data/restraints/parameters
3683 [Rint = 0.0453]
3683/0/272
Multi-scan [29]
1.239
1234 [Rint = 0.0842]
1234/0/92
Multi-scan [29]
1.116
1183 [Rint = 0.0436]
1183/0/95
Multi-scan [29]
1.218
1205 [Rint = 0.0486]
1205/28/95
Multi-scan [29]
1.079
1249 [Rint = 0.0353]
1249/0/75
Multi-scan [29]
1.263
Absorption correction
GOF on F2
Final R indicesa
R1
wR2
0.0381
0.0778
0.0438
0.0994
0.0555
0.1293
0.0334
0.0844
0.0423
0.0966
R indices (all data)
R1
0.0402
0.0528
0.0623
0.0396
0.0451
wR2
0.0796
0.491 and ꢀ0.823
0.1036
1.953 and ꢀ0.526
0.1331
0.862 and ꢀ1.369
0.0874
0.452 and ꢀ0.513
0.0978
0.674 and ꢀ0.838
Largest difference peak and hole (e Åꢀ3
)
a
I > 2r(I).

H.J. Breunig et al. / Journal of Organometallic Chemistry 695 (2010) 1307–1313
1313
produce colorless crystals which were separated by filtration
(0.71 g, 85%). Anal. Calc. for C36H30BrCl3Sb2: C, 48.45; H, 3.39.
Found: C, 48.61; H, 3.66%. MS (ESI, CH3CN), m/z (%), pos.: 429
(100) [Ph4Sb+]; neg.: 506 (2) [Ph2SbBr2Cl2ꢀ], 461 (18)
[Ph2SbBrCl3ꢀ], 417 (100) [Ph2SbCl4ꢀ].
Chemischen Industrie for research support. We thank Dr. M.H.
Dickman for help with XRD.
Appendix A. Supplementary material
CCDC 753670, 753673, 753676, 753678, 753677, 753675,
755367, 753672, 753674 and 753671 contain the supplementary
crystallographic data for compounds 1, 3, 4, 5, 6, 7, 8, 9, 10 and
11. These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_re-
quest/cif. Supplementary data associated with this article can be
found, in the online version, at doi:10.1016/j.jorganchem.2010.
02.016.
4.14. X-ray structure determination
Data were collected on Bruker SMART APEX (1, 3, 8–11), Bruker
KAPPA APEX II (4) and Bruker P4 (5, 6) diffractometers, using
graphite-monochromated Mo Ka radiation. For 1, 3 and 8–11 the
data were collected at room temperature, while for compounds
4–6 the crystals were cooled under a nitrogen stream at low tem-
perature. The details of the crystal structure determination and
refinement for compounds 1 and 3–11 are given in Tables 1 and 2.
The structures were refined with anisotropic thermal parame-
ters. The hydrogen atoms were refined with a riding model and a
mutual isotropic thermal parameter. For structure solving and
refinement the software package SHELX-97 was used [27]. The
hydrogen atoms from methyl groups of compounds 1 and 2 are
disordered over four positions with 25% occupancy for each. The
cations of compounds 3 and 7–10 are disordered; the CH2 frag-
ments of the ethyl groups were modeled over two positions with
occupancy of 0.50/0.50 for 3 and 8, 0.58/0.42 for 7, and 0.50/0.50
for one CH2 and 0.40/0.60 for the other one in 9 and 10. Further at-
tempts to model the disorder for the whole ethyl groups did not re-
sulted in better results. Due to the disorder and crystal symmetry
no hydrogen atoms were calculated for the cations in the above
compounds except compound 7. Compounds 9 and 10 exhibit sub-
stitutional disorder of the halide atoms bonded to antimony, with
Br/Cl in the ratio 0.31/0.69 for 9 and 0.73/0.27 for 10, respectively.
In compound 6 the antimony atoms of the cations are disordered
over two positions with occupancy of 0.10/0.90 and 0.13/0.87,
respectively. The drawings were created with the Diamond pro-
gram [28].
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Acknowledgements
Financial support from National University Research Council
and Ministry of Education and Research of Romania (Research Pro-
jects CNCSIS No. 1456/2008 and PNII-ID 2052/2009) is greatly
appreciated. We thank Universität Bremen and the DAAD for finan-
cial support. A.M.P. thanks the European Social Fund for a Scholar-
ship (Education and Training Program 2008–2013, POSDRU/6/1.5/
S/3) and a research fellowship awarded by BBU Cluj-Napoca,
Romania. We also thank the NATIONAL CENTER FOR X-RAY
DIFFRACTION for the support in the solid state structure
determinations. U.K. thanks Jacobs University and the Fonds der
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