One-step synthesis of pentavalent triphenylantimony derivatives Ph3Sb(OSiR3)2, Ph3Sb(OCH2CH2)2NH and Ph3Sb(OCH2CH2NMe2)2: X

Article abstract of DOI:10.1016/j.jorganchem.2007.09.019

Pentavalent bis(triorganosiloxy)triphenylantimony derivatives, Ph₃Sb(OSiR₃)₂ (R = Me, Ph), were synthesized by reaction of triphenylantimony with trimethyl- or triphenylsilanol in the presence of tert-butylhydroperoxide by

Full text of DOI:10.1016/j.jorganchem.2007.09.019

Available online at www.sciencedirect.com
Journal of Organometallic Chemistry 692 (2007) 5701–5708
www.elsevier.com/locate/jorganchem
One-step synthesis of pentavalent triphenylantimony
derivatives Ph3Sb(OSiR3)2, Ph3Sb(OCH2CH2)2NH
and Ph3Sb(OCH2CH2NMe2)2: X-ray molecular
structure of Ph3Sb(OSiMe3)2
a,
a
a
b
Elena Yu. Ladilina *, Vladimir V. Semenov , Georgii K. Fukin , Aleksey V. Gushchin ,
b
c
d
Viktor A. Dodonov , Irina V. Zhdanovich , Jean-Pierre Finet
a
G.A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences, GSP-445, 49 Tropinin Street, 603950 Nizhny Novgorod,
Russian Federation
b
Department of Organic Chemistry, Nizhny Novgorod State University, 23 Gagarin Avenue, 603950 Nizhny Novgorod, Russian Federation
c
Nizhny Novgorod State Medical Academy, 10/1 Minin Square, 603005 Nizhny Novgorod, Russian Federation
Faculte des Sciences St-Jyrfme, UMR-CNRS 6517, Aix-Marseille University, 13397 Marseille Cedex 20, France
d
Received 5 December 2006; received in revised form 29 August 2007; accepted 24 September 2007
Available online 29 September 2007
Abstract
Pentavalent bis(triorganosiloxy)triphenylantimony derivatives, Ph3Sb(OSiR3)2 (R = Me, Ph), were synthesized by reaction of triph-
enylantimony with trimethyl- or triphenylsilanol in the presence of tert-butylhydroperoxide by the mild reaction conditions (0–5 ꢀC, 2 h).
The reaction of triphenylantimony with diethanolamine in the presence of tert-butylhydroperoxide gave the cyclic compound
Ph3Sb(OCH2CH2)2NH. The mixture of Ph3SbO and Ph3Sb(OCH2CH2NMe2)2 was obtained by the reaction of triphenylantimony with
2-(N,N-dimethylamino)ethanol in the presence of tert-butylhydroperoxide.
ꢁ 2007 Elsevier B.V. All rights reserved.
Keywords: Antimony(V); Peroxide; Silanols; Ethanolamines; Oxidation; 1H, 29Si NMR spectroscopy
1. Introduction
[8], oximes [9,10] and b-diketones [11] as the OH-contain-
ing reagents.
Pentavalent Ph3SbX2 compounds can be obtained by a
one-step oxidative method. This is the reaction of tripheny-
lantimony with OH-containing reagents in the presence of
hydrogen peroxide [1] or the organic hydroperoxide [2].
The simplicity of the procedure and mildness of the reac-
tion conditions are the main advantages of this method.
This method has been used to prepare a range of Sb(V)
compounds by using carboxylic acids [3,4], sulfonic acids
[5], glycols [6], diphenols [7], phenylboric acid, silanediols
The reaction mechanism Ph3Sb with OH-containing
reagents (ROH) in the presence of ButOOH may be visual-
ized as follows. Ph3Sb attacks the peroxide oxygen to give a
hydroxymetallonium ion [12]. Further deprotonation of
OH-containing reagents (ROH) by the strongly basic
ButOꢀ anion produces ButOH and unstable hydroxyalk-
oxy-derivatives of antimony (V) [11] which is converted
into dialkoxy-derivatives of triphenylantimony by means
of the OH-group substitution on treatment with ROH.
+ HOR
- HOBu
+ HOR
OR
OH
Ph3Sb O OBut
H
[Ph3Sb+OH -OBut]
Ph3Sb
Ph3Sb(OR)2
t
- H O
2
*
Corresponding author. Fax: +7 8312 12 74 97.
ð1Þ
E-mail address: llena@iomc.ras.ru (E.Yu. Ladilina).
0022-328X/$ - see front matter ꢁ 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2007.09.019

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E.Yu. Ladilina et al. / Journal of Organometallic Chemistry 692 (2007) 5701–5708
The tert-BuOOH-mediated oxidative method has not
ment in the siloxy derivatives 1 and 2. In compound 1, the
band is wider and more intensive than in compound 2 and
it is shifted by 40 cmꢀ1 to shorter wavelengths (1,
been used for the preparation of disiloxytriorganoanti-
mony derivatives, R3SbðOSiR0 Þ . The compounds of this
3
2
type have been synthesized in two or three-step sequences,
involving the oxidation of triorganoantimony to trio-
rganoantimony(V) dichloride, followed by reaction with
sodium silanolate or with silanol in the presence of ammo-
nia [13,14].
m
max(KBr) = 940 cmꢀ1; 2, mmax(KBr) = 980 cmꢀ1). This
shift results from the more electron-withdrawing effect of
the phenyl substituents in Sb–O–SiPh3 compared to the
effect of the donor methyl groups of the trimethylsiloxy
1
derivative Sb–O–SiMe3. In the H NMR spectrum of 1, a
singlet appears at ꢀ0.02 ppm corresponding to the 18 pro-
tons of the two trimethylsilyl groups and two multiplets at
7.60 and 8.27 ppm correspond to the 15 protons of the
Ph3Sb
Ph3SbCl2
o
80 C, 1h
ð2Þ
ð3Þ
Ph3Sb(OSiMe3)2
Me3SiOH
Me3SiONa
1
SbPh groups. In the H NMR spectrum of Me3SiOSiMe3
2Ph3SiOH;2NH3
!
and Me3SiOSiPh3, a methyl proton resonance appear at
0.06 and 0.10 ppm [15]. In the 29Si NMR spectrum of 1,
the signal appears at 2.4 ppm. This value is very close to
that of the signal observed for hexamethyldisiloxane
Ph3Sb ! Ph3SbCl2
Ph3SbðOSiPh3Þ2
ꢀ2NH4Cl;20 ꢁC;24h
On the other hand, the reaction of triphenylantimony
with bis(trimethylsilyl)peroxide afforded only triphenyl-
antimony oxide and hexamethyldisiloxane, but not
bis(trimethylsiloxy)triphenylantimony contrary to expecta-
tions of authors [2].
1
(6.3 ppm) [16]. Thus, the H and 29Si NMR spectra show
the absence of Me3SiO(Ph3)Sb– fragments electron-with-
drawing influence on SiMe3 group in compound 1. Most
likely, this fragment is electron-donor. In the 29Si NMR
spectrum of 2, a signal appears at ꢀ23.9 ppm, a value very
close to that of the signal observed for hexaphenyldisilox-
ane (ꢀ18.5 ppm). This reflects the similarity of the electro-
negativities of antimony and silicon (1.9 and 1.8,
respectively, in the Pauling scale [17]).
OSiMe3
Ph3Sb
OSiMe3
R3Sb + Me3SiOOSiMe3
Ph3Sb=O + Me3SiOSiMe3
ð4Þ
The compound 1 has been structurally characterized by
X-ray analysis which revealed that the antimony atom
exhibits trigonal-bipyramidal coordination where the Ph-
groups occupy the equatorial positions and the trimethyl-
siloxy groups occupy the apical positions (Fig. 1 and Table
1). The Sb(1)–C(Ph) distances vary in the range of
2.098(2)–2.113(2)E and are typical for Sb–Ar distances
(2.092–2.137E [18–20]). The Sb(1)–O(1) and Sb(1)–O(2)
bond lengths are close to each other [2.006(2)E and
2.012(2)E, respectively]. If we compare the molecular struc-
ture of compound 1 with the structures of different
Ph3Sb(OR)2 derivatives (Table 2), the most striking differ-
ence lies in the lengths of the Sb–O distance that are shorter
than the typical Sb–O distance (2.05E) [21]. Moreover, the
order is: SbOTMS < SbOH < SbOMe. In spite of the steric
bulk of the trimethylsilyl group, the Sb–O bond is the
shortest for the TMS ether (2.009E). Compared to the nor-
mal Sb–O distance of 2.05E, the percentages of contraction
of the Sb–O bond in Ph3Sb(OR)2 derivatives (R = TMS,
H, Me), are 2%, 1.5% and 0.9%, respectively. When the
Sb–O bond is part of a bidentate system such as in ester
compounds Ph3Sb[OC(O)R]2 (R = CPh2OH, CH@CH–
Ph, CF3), the bond lengths Sb–O are somewhat longer
(2.102–2.156E [22,23]). The Si(1)–O(1) and Si(2)–O(2) dis-
tances are 1.617(2)E and 1.624(2)E, respectively and are
close to analogous distances found in Sb(OSiMe3)5 Æ Py
and Sb(OSiMe3)3 Æ Py (1.603–1.657E [24,25]) complexes.
In the three related dihydroxide derivatives Ph3Sb(OR)2
(R = H, Me, TMS), the O–Sb–O angle is practically iden-
tical in the dihydroxide and its TMS ether (178.5ꢀ), but a
slight distortion is induced by the methyl substitution
(175.3ꢀ for the dimethoxy derivative). The Si(1)O(1)Sb(1)
In the present paper, we report the reaction of tripheny-
lantimony with ButOOH in the presence of organosilanols
(trimethylsilanol, triphenylsilanol), or amino-alcohols
(diethanolamine and N,N-dimethylethanolamine).
2. Results and discussion
2.1. Reaction of triphenylantimony with silanols in the
presence of tert-BuOOH
Oxidation of triphenylantimony by ButOOH in the pres-
ence of 2 equivalents of trimethylsilanol or triphenylsilanol
afforded after stirring during 2 h the bis(trimethylsil-
oxy)triphenylantimony 1 or bis(triphenylsiloxy)tripheny-
lantimony 2, respectively. In both cases, the reaction was
carried out under cooling to avoid the competitive forma-
tion of diorganosiloxanes by dehydration of the silanols.
t-BuOOH, toluene
OSiR3
Ph3Sb + 2 R3SiOH
Ph3Sb
o
Na SO , 0-5 C, 2 h
2
4
OSiR3
ð5Þ
1, R=Me, 50% after recrystallization
2, R=Ph, 83%
Both products are stable to air and moisture resistant.
These compounds were described by element analysis and
melting-point [13,14], and compound 1 – by IR spectros-
copy only [13].
1
The IR, H NMR and 29Si NMR spectra of the com-
pounds 1 and 2 have been studied. In the IR spectra of
these compounds, a difference was observed in the position
and intensity of the absorption bands of the Sb–O–Si frag-

E.Yu. Ladilina et al. / Journal of Organometallic Chemistry 692 (2007) 5701–5708
5703
Fig. 1. X-ray molecular structure of compound 1.
Table 1
and Si(2)O(2)Sb(1) angles are close to each other: 153.6(1)ꢀ
and 149.0(1)ꢀ, respectively.
Selected bond lengths and bond angles (x/ꢀ) (d/E) for 1
Bond lengths (E)
Bond angles (x/ꢀ)
In the crystal lattice, the molecules of compound 1 form
dimers due to p–p interaction between the C(1–6) aromatic
rings of neighbouring molecules. The distances between the
centers of the Ph-rings are 4.057(3)E, and the distances
between the planes, in which these rings are disposed, are
equal to 3.674(4)E (Fig. 1). Such distances correspond to
p–p interactions between aromatic rings [32].
The trigonal bipyramidal structure provides high stabil-
ity to compound 1. Indeed, the thermal decomposition of
compound 1 proceeded only under harsh conditions (vac-
uum, 250 ꢀC) to lead to the formation of triphenylantimo-
ny oxide and hexamethyldisiloxane, isolated in only a 13%
yield after 1 h of treatment.
Sb(1)–O(1)
Sb(1)–C(7)
Sb(1)–C(1)
Sb(1)–O(2)
Sb(1)–C(13)
Si(1)–O(1)
2.006(2)
2.098(2)
2.113(2)
2.012(2)
2.110(2)
1.617(2)
O(1)Sb(1)O(2)
O(1)Sb(1)C(7)
O(2)Sb(1)C(7)
O(1)Sb(1)C(13)
O(2)Sb(1)C(13)
C(7)Sb(1)C(13)
O(1)Sb(1)C(1)
O(2)Sb(1)C(1)
C(7)Sb(1)C(1)
C(13)Sb(1)C(1)
Si(1)O(1)Sb(1)
Si(2)O(2)Sb(1)
178.54(7)
90.42(8)
90.76(8)
89.84(8)
88.84(8)
118.78(9)
89.74(8)
90.38(8)
121.25(9)
119.96(9)
153.63(11)
149.04(11)
250 ꢁC;Vacuum
Ph3SbðOSiMe3Þ2
Ph SbOþMe SiOSiMe ð6Þ
ƒƒƒƒƒƒƒƒ!
3
3
3
Table 2
The thermal stability of Ph3Sb(OSiMe3)2 confirms the
conclusion that the reaction of Ph3Sb with Me3SiOOSi-
Me3, leading to Ph3SbO and Me3SiOSiMe3 under mild
conditions, does not involve the intermediate formation
of Ph3Sb(OSiMe3)2 [2].
Comparison of mean distances in some trigonal bipyramidal pentavalent
triphenylantimony derivatives
Compound
d(Sb–O)ap (E) O–Sb–O (ꢀ) Reference
1 Ph3Sb(OTMS)2
2.009
178.54
This work
Ph3Sb(OMe)2
Ph3Sb(OH)2
Ph3Sb(ON@CHPh)2
Ph3Sb(ON@CMe2)2
Ph3Sb(ON@CMeC5H4N-2)2 2.068
Ph3Sb(OAc)2
Ph3Sb[OCOC(OH)Ph2]2
Ph3Sb(OCOCF3)2
Ph3Sb(OCO-thiophenyl-2)2
Ph3Sb(OCO-pyr-2)2
2.033
2.021
2.065
2.047
175.3
178.5
176.46
176.0
172.78
176.1
171.98
175.5
176.68
169.9
[26]
[27]
[9]
2.2. Reaction of triphenylantimony with ethanolamines in the
presence of tert-BuOOH
[9]
[28]
[29]
[22]
[23]
[30]
[31]
Unlike triorganosilanols, ethanolamines are able to be
either mono-, bi-, tri- or tetradentate ligands of anti-
mony(V) with or without participation of the amino-group,
respectively. Some of examples of organoantimony
compounds containing ethanolamine ligands have been
2.130
2.223
2.134
2.120
2.142

5704
E.Yu. Ladilina et al. / Journal of Organometallic Chemistry 692 (2007) 5701–5708
previously reported. Nomura et al. showed that heating of
triphenylantimony oxide in N-methylaminoethanol or
reaction of N-methylaminoethanol with Ph3Sb(OMe)2 pre-
pared in situ results to the formation of bis [(N-methyl-2-
aminoethoxy)hydroxydiphenyl]antimony oxide [33].
atoms is more pronounced. The proton of the >N-H group
appear as a multiplet by reason of the nitrogen atom slow
inversion because of intermolecular hydrogen bonds or
intramolecular interaction between Sb and N atoms. D.
Kraft and M. Wieber [34] establish that heterocycle 3 exist
ð7Þ
Kraft and Wieber [34] used an reaction of pentaphenyl-
stibane and methoxytetraphenylstibane with diethanola-
mine or triethanolamine to obtain alkoxy derivatives of
antimony(V):
in both-conformation. This compound was not studied by
IR spectroscopy. Authors suppose that this conformation
is stable because of strong intramolecular coordination
bond between Sb and N. Nevertheless in the IR spectrum
of compound 3 the absorption band of N-H stretching
vibrations is in the range of 3150 cmꢀ1, typical for associ-
ated NH groups. The absence of absorption bands, corre-
sponding to the fragment R3HN+, indicated that there is
no firm strong coordination bond between the atoms of
nitrogen and antimony. For the analogous silicon com-
pound, Ph2Si(OCH2CH2)2NH, the presence of a very loose
intramolecular interaction is known [34]. The experimental
dipole moment of this compound is by far closer to the cal-
culation dipole moment for both-conformer without the
Si N bond then to the calculation dipole moment for
both-conformer with the Si N bond [35]. Therefore,
the geometry of the both-conformer allows formation of
the intramolecular coordination bond, but interaction
between Sb and N atoms in compound 3 is very weak.
The reaction of triphenylantimony with N,N-dimethyl-
2-aminoethanol and tert-butyl hydroperoxide in a molar
ratio 1:2:1 gave a clear viscous liquid, which according data
boiling;3h
3SbPh4RþNðCH2CH2OHÞ3
NðCH CH OSbPh Þ
ƒƒƒƒ!
2
2
4
3
ꢀ3RH
R¼Ph;OMe
ð8Þ
boiling;3h
ƒƒƒƒ!
ꢀ2PhH
SbPh5 þHNðCH2CH2OHÞ2
HNðCH CH OÞ SbPh
2
2
3
2
50%
ð9Þ
In the oxidative-addition reaction of triphenylantimony
with glycols [6], if the hydroxy groups of the glycol are sep-
arated by a sufficient number of carbon atoms, the reaction
leads to the formation of polymers. In an extension of this
previous work, we investigated the reaction of triphenylan-
timony with diethanolamine in presence ButOOH. Since the
OH groups are rather separated from each other, we consid-
ered that the reaction products should have a polymer
structure. When triphenylantimony was treated with dieth-
anolamine and ButOOH in equimolecular amounts, a white
precipitate was formed. Its HPLC analysis showed that the
product is in fact a monomeric compound, with a molecular
weight corresponding to the eight-membered heterocycle
(3), 5,5,5-triphenyl-4,6-dioxa-5-stibaperhydroazocine.
1
of H NMR spectroscopy and the HPLC analysis was a
mixture of bis(N,N-dimethyl-2-aminoethoxy)triphenylanti-
mony (4) and Ph3SbO (ꢂ20% mol). We were unable neither
to remove triphenylantimony oxid from the final product
nor to decrease its amount. Apparently Ph3SbO is well sol-
uble in compound 4.
rt;24h;ButOOH
SbPh3 þ NðCH2CH2OHÞ2
NðCH CH OÞ SbPh
3
ƒƒƒƒƒƒƒ!
2
2
3
2
ꢀButOH;H2O
SbPh3 þ 2HOCH2CH2NMe2
ð10Þ
rt;ButOOH
1
The H NMR spectrum of compound 3 presented sig-
nals corresponding to three phenyl groups (multiplet in
the range of 7.32–7.76 ppm), methylene groups of an oxy-
gen atom (multiplet at 4.05 ppm) and a nitrogen atom (a
Ph3SbðOCH2CH2NMe2Þ2
ð11Þ
ƒƒƒƒƒ!
ꢀButOH;H2O
4
In the IR spectrum, absorption bands at 2820, 2775,
2725 cmꢀ1 correspond to the stretching vibrations of the
methyl groups C-H bonds of the nitrogen atom. Their local-
ization indicates the absence of coordination between the
nitrogen atom and the antimony atom, in spite of the high
basicity of tertiary amino groups. In this spectrum, four
C-H absorption bands (2980, 2945, 2860, 1460 cmꢀ1),
belonging to CH2 groups, a very intensive absorption band
at 1050 cmꢀ1, corresponding to the vibrations of the Sb-O-C
fragment and a series of bands, corresponding to phenyl
substituents vibrations of the antimony atom (3060, 1605,
widened doublet at 2.76 ppm and
a multiplet at
3.19 ppm), and also to ˜N–H proton (multiplet at
2.97 ppm). Due to the cyclic nonplanar structure, the axial
and equatorial protons of methylene groups bound to the
nitrogen atom and the oxygen atoms are not equivalent.
The protons of the CH2O groups appear as a multiplet,
while the protons of the CH2N groups appear as two sep-
arate signals (axial and equatorial). Hence, it may be con-
cluded that the nonequivalence of the latter hydrogen

E.Yu. Ladilina et al. / Journal of Organometallic Chemistry 692 (2007) 5701–5708
5705
1580, 1480, 1430, 1070, 830, 700, 455 cmꢀ1) were observed.
Two absorption bands at 650 and 670 cmꢀ1 can be
explained by the presence of triphenylantimony oxide, as
an impurity.
offers a mild way of synthesis of these compounds that
appear to be rather stable to thermolysis conditions. With
long chain glycols, the cyclic compound was formed exclu-
sively instead of the polymer that might have been expected.
1
In the H NMR spectrum, the signals corresponding to
the phenyl groups (a multiplet in the 7.32–7.76 ppm range),
methylene groups bound to the oxygen atom (a triplet at
3.22 ppm) and methylene (a multiplet at 2.38 ppm) and
methyl (a singlet at 2.02 ppm) groups linked to the nitrogen
atom were present. The yield of 4 depends both on the
reaction time and on the presence of water in the reaction
4. Experimental
4.1. General remarks
IR spectra were recorded on a Specord 75IR spectro-
photometer in the 4000 ꢀ400 cmꢀ1 range, for suspension
in Nujol or thin film between two optical KBr caps.
NMR spectra were measured with a Bruker Avance
DPX-200 spectrometer (200 MHz for 1H, 50 MHz for
13C, 39.7 MHz for 29Si) at 25ꢀC using CDCl3 as solvent
and Me4Si as internal standard. Aminoalcohols and trim-
ethylsilanol were analysed on a Tsvet-530 gas chromato-
graph with a 0.3 · 200 cm stainless-steel column (5%
SE-30 on Chromaton N-AW-DMCS). HPLC analyses
were carried out on a microcolumn liquid chromatograph
Milichrom-1A equipped with a 64 · 2 mm column, packed
with Separon-SGX, Silasorb nitrile with a 5 lm particle
diameter, and UV detector. To analyse compound 3, eluent
(hexane: THF 1:1) was used with detection at k = 230 nm,
and for compound 4 eluent (hexane: THF 10:1) was used
with detection at k = 220 nm, the eluent velocity being
200 ll/min. The molecular mass of compound 3 was deter-
mined by the Rast method [37]. THF, toluene and hexane
were distilled from appropriate drying agents. Diethanola-
mine and N,N-dimethyl-2-aminoethanol were purchased
(Kaprolaktam Joint-Stock Company, Dzerzhinsk, Russia)
and distilled under reduced pressure. tert-Butylhydroper-
oxide [38], triphenylantimony [39], trimethylsilanol and
triphenylsilanol [40] were synthesized by known methods.
Hexaphenyldisiloxane was prepared by reaction of triphe-
nylsilanol with di-n-butylamine [41], m.p. 221ꢀC, lit. 222–
224 ꢀC; 29Si NMR, d: ꢀ18.5; 13C NMR, d: 127.8, 129.8,
135.2, 135.5.
mixture. In
a preliminary experiment, the reaction
appeared as sluggish and was left for a 24 h at room tem-
perature to afford a 12% crude yield of 4. When using
anhydrous Na2SO4, the yield increased from 12 to 32%.
Presence of the tertiary amino groups with electron-donat-
ing methyl substituents increases the basicity of the com-
pound. Moreover, as the mobility of the nitrogen atom is
not constrained by inclusion in a ring, compound 4 is more
easily hydrolyzed by water and air moisture than the cyclic
compound 3. In compound 4, hydrolysis of the alkoxy-
antimony bonds by intramolecular catalysis by the basic
nitrogen atom explains the poor yields of the product in
the reaction performed in absence of sodium sulfate. When
the reaction of triphenylantimony with N,N-dimethyl-2-
aminoethanol and ButOOH was made with a 1:1:1 ratio,
we expected to obtain either hydroxy-alkoxy-derivative
Sb(V) analogous to those described by V.A. Zinov’eva
et al. [36] (Ph3Sb(OH)OCH2CH2NH2), or bis[(N,N-
dimethyl-2-aminoethoxy)triphenyl]antimony oxide. The
formation of the latter was thought to be more likely.
However, triphenylantimony oxide turned out to be the
only antimony containing product, when the reaction was
carried out for 24 h. When reducing the reaction time to
2 h and using anhydrous sodium sulfate, the mixture of
compound 4 with Ph3SbO was obtained, as confirmed by
1
IR and H NMR spectroscopy and HPLC analysis.
rt;ButOOH
SbPh3 þHOCH2CH2NMe2
ƒƒƒƒƒƒ!
ꢀButOH;H2O
4.2. Synthesis of bis(trimethylsiloxy)triphenylantimony (1)
H2O
Ph3SbðOCH2CH2NMe2Þ2
Ph SbO
3
ƒƒƒƒƒƒƒƒƒ!
ꢀ2HOCH2CH2NMe2
To a suspension of Na2SO4 (0.50 g) in solution of triph-
enylantimony (1.50 g, 4.25 mmol) and trimethylsilanol
(0.77 g, 8.54 mmol) in toluene (30 ml) a solution of
ButOOH (0.39 g, 4.38 mmol) in toluene (20 ml) was added
dropwise at 0–5 ꢀC. The reaction mixture was stirred over
2 h. Then, the reaction mixture was filtered; the solvent
and the volatile products were distilled under reduced pres-
sure. The remaining white solid was recrystallized from hex-
ane to afford compound 1 (1.12 g, 50%) as colourless,
transparent crystals. Anal. Calc. for C24H33O2SbSi2: C,
54.24; H, 6.26; Sb, 22.91; Si, 10.57. Found: C, 53.90; H,
6.34; Sb, 23.57; Si, 11.08%. IR, (cmꢀ1): m 940 (Sb–O–Si),
1250, 800 (Si–Me), 3060, 1590, 1430, 1070, 740, 695, 455
(Sb–Ph). 1H NMR: d ꢀ0.02 (s, 18H, CH3Si); 7.60,
8.27 (both m, 15H, Ph–Sb). 13C NMR: d 3.07 (CH3–Si),
128.9, 130.9, 134.8, 140.4 (Ph–Sb). 29Si NMR: d 2.4. Slow
ð12Þ
Therefore compound 4 formed very rapidly. Then it is
hydrolyzed by reason of the high basicity of tertiary amino
groups.
3. Conclusion
The one-step oxidative reaction of triphenylantimony
with OH-containing acidic reagents in the presence of tert-
butylhydroperoxide can be conveniently extended to sila-
nols as well as to monoalcohols, even in the presence of a
neighbouring amino group or to long chain glycols. In con-
trast to previous attempts [2] that failed to produce the disi-
lyloxy derivatives of triphenylantimony, the present method

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E.Yu. Ladilina et al. / Journal of Organometallic Chemistry 692 (2007) 5701–5708
recrystallization from hexane afforded of a monoclinic form
that was used for X-ray crystal structure determination.
ButOOH, the solution became turbid. The reaction mixture
was stirred over 2 h. When the temperature of the mixture
reached room temperature, a white precipitate appeared.
The solution was decanted; the precipitate was stirred for
2 h in 20 ml of distilled water, filtered, washed with toluene,
acetone and air-dried to give 2 (3.20 g, 83%). Compound is
partly soluble in CHCl3 and THF and insoluble in CCl4
and acetone. Anal. Calc. for C54H45O2SbSi2: C,71.76; H,
5.02; Sb, 13.47; Si, 6.21. Found: C, 71.60; H, 4.84; Sb,
13.39; Si, 6.25%. IR (cmꢀ1): m 980 (Si–O–Sb), 3060, 1595,
1110, 740, 695, 520, 455 (Si–Ph, Sb–Ph). 29Si NMR: d
ꢀ23.9.
4.2.1. X-ray crystal structure determination of compound 1
The data were collected on a SMART APEX diffractometer
(graphite-monochromated, Mo Ka-radiation, /–x-scan
technique, k = 0.71073E). The structure was solved by
direct methods and was refined on F2 using all reflections
with SHELXTL [42] package. SADABS [43] was used to perform
area-detector scaling and absorption corrections. All non-
hydrogen atoms were refined anisotropically. The hydro-
gen atoms were found from Fourier synthesis and isotrop-
ically refined. The details of crystallographic collection and
refinement data are given in Table 3. Selected bond lengths
and bond angles are given in Table 1.
4.4. Synthesis of 5,5,5-triphenyl-4,6-dioxa-5-
stibaperhydroazocine (3)
4.2.2. Thermal decomposition of compound 1
A solution of diethanolamine (0.24 g, 2.27 mmol) in
THF (5 ml) was added to a solution of triphenylantimony
(0.80 g, 2.27 mmol) in toluene (20 ml). Then, a solution of
ButOOH (0.21 g, 3.34 mmol) in toluene (20 ml) was added
dropwise over 1 h. The solution became turbid. The reac-
tion mixture was kept at room temperature for 24 h. The
white precipitate was filtered, washed in toluene and air-
dried to afford 3 (1.20 g, 62%), m.p. 174 ꢀC. IR (cmꢀ1): m
3150, 1540 (N–H), 2820, 2775, 2725, (N–CH3), 1050 (Sb–
0.87 g of compound 1 was heated in a vacuum-sealed
two-arm ampule for 1 h at 250 ꢀC. The volatile products
(0.03 g of a transparent liquid) were condensed in the side
arm. According to GLC analysis and IR spectroscopy, it
was identified as hexamethyldisiloxane, obtained in a 13%
yield. The residue is a mixture of the initial product and
triphenylantimony oxide, as confirmed by IR spectroscopy.
1
4.3. Synthesis of bis(triphenylsiloxy)triphenylantimony (2)
O–C), 3060, 1580, 1430, 1070, 740, 700, 455 (Sb-Ph). H
NMR: d 2.76 (2H; NCH2), 2.97 (m, 1H; NH), 3.19 (m,
2H; NCH2), 4.05 (m, 4H; OCH2), 7.32–7.76 (m, 15H; Sb-
Ph). M (RAST method) 478, calc. 456. Anal. Calc for
C22H24O2NSb: C, 57.92; H, 5.30; Sb, 26.69. Found: C,
58.04; H, 5.28; Sb, 26.00%.
To a suspension of Na2SO4 (0.50 g) in solution of triph-
enylantimony (1.50 g, 4.25 mmol) and triphenylsilanol
(2.35 g, 8.49 mmol) in toluene (30 ml) a solution of
ButOOH (0.39 g, 4.38 mmol) in toluene (20 ml) was added
dropwise at 0–5 ꢀC. After the end of the addition of
4.5. Reaction of triphenylantimony with
2-(N,N-dimethylamino)-ethanol in the presence
of ButOOH in the ratio of 1:2:1
Table 3
Details of crystallographic collection and refinement data for 1
Empirical formula
Molecular weight
Crystal system
Temperature (K)
Space group
Unit cell dimensions
a (E)
C24H33O2SbSi2
531.43
Monoclinic
100(2)
P2ð1Þ=n
(a) A solution of ButOOH (0.32 g, 3.51 mmol) in toluene
(15 ml) was added dropwise to a stirred solution of
triphenylantimony (1.20 g, 3.40 mmol) and 2-(N,N-
dimethylamino)ethanol (0.61 g, 6.85 mmol) in toluene
(30 ml). The mixture was stirred for 2 h and then left
at room temperature for 24 h. Removal of the vola-
tiles under reduced pressure gave a white viscous res-
idue, that was extracted with hot hexane (3 · 10 ml) to
afford 0.26 g of a transparent viscous liquid, as a mix-
ture of bis[2-(N,N-dimethylamino)ethoxy]tripheny-
lantimony (4) and triphenylantimony oxide (ꢂ20%
mol). The yield of compound 4 was 12%. IR (cmꢀ1):
m 2820, 2775, 2725 (N–CH3), 2980, 2945, 2860, 1460
(C-H), 1050 (Sb–O–C), 3060, 1605, 1580, 1480,
8.7426(5)
27.7083(15)
10.6657(6)
101.9060(10)
2528.1(2)
4
1.396
1.203
1088
0.08 · 0.08 · 0.08
58
b (E)
c (E)
b(ꢀ)
V (E3)
Z
Dcalc (g cmꢀ3
)
Absorption coefficient (mmꢀ1
F(000)
)
Crystal size (mm3)
2hmax (ꢀ)
1
Reflections collected
Independent reflections
Absorption correction
Data/ restraints/ parameters
Goodness-of-fit on F2
R1/wR2 (I > 2r(I))
R1/wR2 (all data)
26598
1430, 1070, 830, 700, 455 (Sb–Ph). H NMR: d 2.02
(C; 12H; N(CH3)2), 2.38 (m, 4H; NCH2), 3.22 (t,
4H; OCH2), 7.32–7.76 (m, 15H; Sb–Ph).
6705 [Rint = 0.0264]
SADABS
6705/ 0/ 394
1.303
0.0396/0.0802
0.0431/0.0815
ꢀ0.874/1.036
(b) To the suspension of Na2SO4(1.2 g) in a solution of
triphenylantimony (1.20 g, 3.40 mmol) and N,N-
dimethyl-2-aminoethanol (0.61 g, 6.85 mmol) in tolu-
ene (30 ml) a solution of ButOOH (0.32 g, 3.51 mmol)
Largest diffraction peak and hole (e Eꢀ3
)

E.Yu. Ladilina et al. / Journal of Organometallic Chemistry 692 (2007) 5701–5708
5707
in toluene (15 ml) was added dropwise over 2 h. The
References
reaction was stirred for 24 h. After the solvent and
the easily-volatile products were removed, hexane
extraction of the residue gave 0.73 g of compound 4
isolated as a mixture with triphenylantimony oxide
(ꢂ20% mol). The yield of compound 4 is 32%.
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4.6. The reaction of triphenylstibium with
2-(N,N-dimethylamino)-ethanol in the presence
of ButOOH in the ratio of 1:1:1
(a) The solution of 0.32 g (3.51 mmol) of ButOOH in
15 ml of toluene was added dropwise over 1 h under
stirring to the solution of 1.20 g (3.40 mmol) of tri-
phenylstibin and 0.30 g (3.36 mmol) of 2-(N,N-
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(b) To the suspension of 1.20 g Na2SO4 in the solution of
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(3.36 mmol) of 2-(N,N-dimethylamino)-ethanol in
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:
2820, 2775, 2725 (N–CH3), 2980, 2945, 2860, 1460
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This work was supported by a RF President grant (Pro-
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CCDC 264895 contains the supplementary crystallo-
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