Oxidation of tetraaryldistibanes: Syntheses and crystal structures of diarylantimony oxides and peroxides, (R2Sb)2O, (R2Sb)4O6 and (R2SbO)4(O2)2 (R = Ph, o-

Article abstract of DOI:10.1016/S0022-328X(01)01466-8

Tetraaryldistibanes, (R₂Sb)₂ (R = Ph, o-Tol, p-Tol) are synthesized by the reactions of R₂SbNa with BrCH₂CH₂Br in liquid ammonia. They react with air oxygen to form (R₂Sb)₂O and

Full text of DOI:10.1016/S0022-328X(01)01466-8

Journal of Organometallic Chemistry 648 (2002) 209–213
www.elsevier.com/locate/jorganchem
Oxidation of tetraaryldistibanes: syntheses and crystal structures of
diarylantimony oxides and peroxides, (R2Sb)2O, (R2Sb)4O6 and
(R2SbO)4(O2)2 (R=Ph, o-Tol, p-Tol)
H.J. Breunig *, T. Kru¨ger, E. Lork
Institut fu¨r Anorganische und Physikalische Chemie, Uni6ersita¨t Bremen, Fachbereich 2, Postfach 330440, D-28334 Bremen, Germany
Received 30 August 2001; received in revised form 5 October 2001; accepted 17 October 2001
Abstract
Tetraaryldistibanes, (R2Sb)2 (R=Ph, o-Tol, p-Tol) are synthesized by the reactions of R2SbNa with BrCH2CH2Br in liquid
ammonia. They react with air oxygen to form (R2Sb)2O and (R2Sb)4O6. The reactions of (R2Sb)4O6 with H2O2 give peroxides,
(R2SbO)4(O2)2. Single-crystal X-ray structure analyses reveal that the conformations of the (R2Sb)2O molecules are close to
syn–syn (R=Ph) or to syn–anti (R=o-Tol, p-Tol). (Ph2SbO)4(O2)2 is an antimony-oxygen cluster with m4-peroxo ligands.
© 2002 Elsevier Science B.V. All rights reserved.
Keywords: Antimony; Oxygen; Peroxides; X-ray diffraction
oxides, (R2Sb)4O6, and peroxo clusters, (R2SbO)4(O2)2.
A part of the results was already reported in a short
1. Introduction
communication [5]. (R2Sb)2O (R=Ph [1], p-Tol [1]),
and (R2Sb)4O6 (R=Ph [6], o-Tol [7]) are known com-
pounds, which were prepared before by other methods.
Tetraorganodistibanes, (R2Sb)2, (R=alkyl, aryl [1])
are extremely air sensitive compounds. Many alkyl
derivatives ignite spontaneously when exposed to air.
Tetraaryldistibanes are less reactive, but in solution
they also readily absorb oxygen from the atmosphere.
2. Results and discussion
Reactions of distibanes with air have been studied since
the 1920s and the formation of a stibinic acid
R2Sb(O)OH (R=Me) [2] and a peroxide R2SbOOSbR2
(R=Ph) [3] were reported in the earlier literature.
Later we used infrared and mass spectroscopy to show
that the air oxidation of tetraalkyldistibanes leads to
monoxides (R2Sb)2O (R=Me, Et, i-Pr) [4] in the first
step. It is, however, difficult to stop the oxidation of the
alkyl derivatives at this stage and the products formed
by complete oxidation are ill defined [2,4]. The expecta-
tion that under protection of aryl groups the stepwise
oxidation might be feasible prompted our study of
reactions of representative tetraaryldistibanes, (R2Sb)2
(R=Ph, o-Tol, p-Tol) with air and H2O2 and we
report here the syntheses of monoxides, (R2Sb)2O, hex-
2.1. Synthesis and oxidation of (R2Sb)2 and crystal
structures of (R2Sb)2O (R=Ph, o-Tol, p-Tol)
The tetraaryldistibanes, (R2Sb)2 (R=Ph [8], o-Tol,
p-Tol) were prepared as yellow solids by reactions of
R2SbNa with BrCH2CH2Br and crystallization from
diethylether. This method, which is well known for the
synthesis of the phenyl derivative, is equally useful for
the preparation of the tolyl compounds, although the
yields are low. (o-Tol2Sb)2 is a novel distibane, whereas
(p-Tol2Sb)2 is known for a long time as a product of
the reduction of R2SbI with sodium hypophosphite [9].
The monoxides (R2Sb)2O (R=Ph, o-Tol, p-Tol)
form in quantitative yields, when solutions of the dis-
tibanes in diethyl ether are exposed to the air under
conditions that allow very slow absorption of oxygen.
This process is easily achieved by repeatedly opening
* Corresponding author. Tel.: +49-421-218-2266; fax: +49-421-
218-4042.
E-mail address: breunig@chemie.uni-bremen.de (H.J. Breunig).
0022-328X/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)01466-8

210
H.J. Breunig et al. / Journal of Organometallic Chemistry 648 (2002) 209–213
and closing the stopper of the reaction flasks until the
yellow solutions discolour.
by hydrolysis of Ph2SbCl. In contrast, both tolyl com-
pounds adopt conformations close to syn–anti ((o-
Tol2Sb)2O: €1=36.0°, €2=160.3°; (p-Tol2Sb)2O:
€1=7.4°, €2=172.7°). This unspecific distribution of
torsional angles € suggests that the conformations of
the molecules are almost equal in energy. For (R2Sb)2O
(R=Ph, o-Tol, p-Tol) the differences in energy be-
tween the various conformations are not known. Calcu-
lations for (Me2Sb)2O revealed that the syn–anti
conformer is only 4.6 kJ mol−1 higher in energy than
the syn–syn form [10]. Almost equal amounts of both
conformers are present in the gas phase [10]. In crystals
of (Me2Sb)2O, however, the syn–anti conformation is
adopted exclusively. This preference results from the
association of the molecules through intermolecular
Sb···O contacts with the formation of a [(Me2Sb)2O]x
chain [11]. In crystals of (R2Sb)2O (R=Ph, o-Tol,
p-Tol) the molecules are only loosely packed to stacks
without unusual contacts between them (intermolecular
SbꢀSb distances ]520.5(4) pm). Consequently the
packing forces are weak and a relatively wide distribu-
tion of dihedral angles results.
(R2Sb)2+1/2 O2“(R2Sb)2O R=Ph, o-Tol, p-Tol
(1)
Advantages of the oxidation (1) compared with hy-
drolyses of diarylantimony halides [1] are simple work-
up procedures and high yields.
Interesting aspects of the structures of the (R2Sb)2O
molecules are the conformational preferences, which
are described by the EpꢀSbꢀOꢀSb torsional angles €.
Ep stands for the assumed direction of the lone pair at
the antimony atoms. With assignment of the terms syn
and anti for angles of 0 and 180°, the extreme confor-
mations are syn–syn and syn–anti [10,11].
The molecular structures of (R2Sb)2O (R=Ph, o-
Tol, p-Tol) were determined by X-ray crystallography
on single crystals obtained from diethyl ether or tolu-
ene. They are depicted in Fig. 1. Crystallographic data
are presented in Table 1. Despite the close relations
between these molecules their conformations are not
uniform. The structure of (Ph2Sb)2O consists of
molecules in a conformation close to syn–syn (€1=
7.1°, €2=43.9°), with geometric data similar to the
values reported by Bordner and Andrews [12] for a
sample of (Ph2Sb)2O, which presumably was obtained
The SbꢀO bond lengths of (R2Sb)2O (R=Ph,
197.1(3), 197.8(3); R=o-Tol, 196.7(2), 197.8(2); R=p-
Tol, 196.7(4), 198.6(4) pm lie in the range for single
bonds not involved in intermolecular interactions, cf.
(Me2Sb)2O, 198.8(5) [11]; (RSbO)4 (R=(Me3Si)2CH),
196.8(3), 197.0(3) pm [13]. The SbꢀOꢀSb angle in the
(R2Sb)2O molecules is a little wider for the o-tolyl
derivative (126.5(1)°) than for the phenyl (121.4(2)°), or
p-tolyl (122.2(2)°) compound. Similar values were
found for (Me2Sb)2O (123.0(3)) [11] and (RSbO)4 (R=
(Me3Si)2CH) (122.3(2)°) [13].
Fig. 1. Left: structure of (Ph2Sb)2O, distances (pm) and angles (°), Sb(1)ꢀO(1) 197.8(3), Sb(2)ꢀO(1) 197.1(3); Sb(1)ꢀC(1) 215.6(5), Sb(1)ꢀC(8)
214.3(4); SbꢀOꢀSb 121.4(2). Centre: structure of (o-Tol2Sb)2O, Sb(1)ꢀO(1) 197.8(2), Sb(2)ꢀO(1) 196.7(2); Sb(1)ꢀC(1) 215.5(3), Sb(1)ꢀC(8) 215.4(3),
Sb(2)ꢀC(15) 216.9(3), Sb(2)ꢀC(22) 215.0(3); SbꢀOꢀSb 126.5(1). Right: structure of p-Tol2Sb2O, Sb(1)ꢀO(1) 196.7(4), Sb(2)ꢀO(1) 198.6(4);
Sb(1)ꢀC(1) 213.6(5), Sb(1)ꢀC(8) 215.0(5), Sb(2)ꢀC(15) 215.6(5), Sb(2)ꢀC(22) 214.6(5); SbꢀOꢀSb 122.2(2).

H.J. Breunig et al. / Journal of Organometallic Chemistry 648 (2002) 209–213
211
Table 1
Crystal data and structure refinement parameters
(Ph2Sb)2O
(o-Tol2Sb)2O
(p-Tol2Sb)2O
(Ph2SbO)4(O2)2
Empirical formula
Formula mass (g mol−1
Colour
Crystal size (mm)
Radiation (pm)
Temperature (K)
Crystal system
Space group
Unit cell dimensions
a (pm)
C24H20OSb2
567.90
Colourless
0.6×0.4×0.4
71.073
173(2)
Monoclinic
P21/n
C28H28OSb2
624.00
Colourless
0.6×0.4×0.4
71.073
C28H28OSb2
624.00
Colourless
0.7×0.4×0.4
71.073
173(2)
Orthorhombic
Pna21
C48H40O8Sb4
1231.80
Colourless
0.5×0.4×0.4
71.073
173(2)
Monoclinic
P21/c
)
173(2)
Triclinic
(
P1
591.5(1)
2976.2(3)
1201.4(1)
90
95.26(1)
90
2.1061(5)
4
1.791
2.576
2.67–27.50
5907
4234 (Rint=0.0293)
246
0.0337
827.7(1)
1105.0(2)
147.8(3)
87.69(2)
82.37(2)
68.85(2)
1.2494(4)
2
1.659
2.179
2.66–27.49
6349
5094 (Rint=0.0218)
287
1460.7(2)
2776.1(3)
611.3(1)
90
90
90
2.4789(6)
4
1.672
2.196
2.61–27.50
6736
3250 (Rint=0.0382)
287
0.0269
1356.6(3)
1754.6(4)
1876.1(3)
90
98.97(2)
90
4.411(2)
4
1.855
2.477
2.57–27.50
20 315
10 127 (Rint=0.0364)
543
0.0396
b (pm)
c (pm)
h (°)
i (°)
k (°)
V (nm3)
Z
zcalc (g cm−3
)
v (mm−1
q Range (°)
)
Reflections collected
Independent reflections
Parameters refined
R1
0.0261
wR2
0.0776
0.0685
0.0659
0.0888
R indices (all data)
R1=0.0491,
wR2=0.0776
R1=0.0307,
wR2=0.0685
1.035 and −0.531
R1=0.0300,
wR2=0.0659
0.747 and −0.660
R1=0.0732,
wR2=0.0888
0.806 and −0.815
Largest difference peak and hole 1.138 and −0.686
−3
,
(e A
)
Absorption correction
DIFABS [16]
DIFABS [16]
DIFABS [16]
DIFABS [16]
Refinement method
Full-matrix least-squares Full-matrix least-squares Full-matrix least-squares Full-matrix least-squares
on F2
on F2
on F2
on F2
Diffractometer
Siemens P4
Siemens P4
Siemens P4
Siemens P4
2.2. Synthesis of (R2Sb)4O6 and (R2SbO)4(O2)2
(R=Ph, o-Tol, p-Tol)
Addition of excess H2O2 to (R2Sb)4O6 results in the
formation of the peroxo clusters (R2SbO)4(O2)2 (R=
Ph, o-Tol [5], p-Tol) as white crystalline solids, which
in contrast to the hexoxides that are very well soluble in
organic solvents. The crystals are stable for a long time.
Solutions decompose after several weeks at room
temperature.
Injection of a flow of air into solutions of distibanes,
(R2Sb)2 or monoxides, (R2Sb)2O, in diethyl ether or
other organic solvents leads to complete oxidation with
precipitation of tetrakis(diarylantimony)hexoxides,
(R2Sb)4O6 (R=Ph, o-Tol, p-Tol). The hexoxides (stib-
inic acid anhydrides) are white air stable solids, insolu-
ble in organic solvents and water.
(R2Sb)4O6+2H2O2“(R2SbO)4(O2)2+2H2O
R=Ph, o-Tol, p-Tol
(3)
Mass spectra obtained with the chemical ionization
technique contain the molecular ions as the most inten-
sive signals. The H-NMR spectra show that all phenyl
2(R2Sb)2O+2O2“(R2Sb)4O6 R=Ph, o-Tol, p-Tol
(2)
1
The identity of the hexoxides was proved by elemental
analyses and mass spectroscopy. Molecular ions were
obtained by chemical ionization techniques. Electron
impact spectra contain signals of the fragments M+−
R at highest mass. Attempts to grow crystals failed due
to the low solubility of the compounds. Single crystals
of (Ph2Sb)4O6 [6] and (o-Tol2Sb)4O6 [7] suitable for
X-ray analysis were obtained from other sources and
their structures were reported.
groups have equivalent positions. The crystal structure
of (Ph2SbO)4(O2)2 was determined by X-ray structure
analysis on single crystals obtained from a solution in
toluene at −23 °C. The crystallographic data are given
in Table 1. A view of the molecular structure is de-
picted in Fig. 2. The structure contains a puckered
(SbO)4 ring, where antimony atoms approximately oc-
cupy the corners of a square. Two mutually perpendic-
ular OꢀO units are in capping positions above and

212
H.J. Breunig et al. / Journal of Organometallic Chemistry 648 (2002) 209–213
below the plane of the antimony atoms closing the
antimony oxygen cage.
3. Experimental
The good solubility and the relative high thermal
stability of the molecules may be explained by the
coordinative saturation of the atoms in the cage and by
the shielding through the external phenyl groups. The
OꢀO bond lengths of the peroxide bridges (mean 147
pm) as well as the SbꢀO distances in the (SbO)4 ring
(mean 196 pm) correspond to normal single bonds. The
distances between the antimony atoms and the oxygen
atoms of the peroxide groups (mean 223 pm) are
longer. As expected, there are only subtle differences
between the structures of the phenyl- and the o-tolyl
compound [5]. Attempts to use these compounds as
The experiments were performed in an Ar atmo-
sphere, using dried solvents distilled under Ar. Ph4Sb2
[8], o-Tol3Sb [14] and p-Tol3Sb [15] were prepared as
reported.
3.1. Synthesis of tetratolyldistibanes
(a) o-Tol4Sb2: 15.8 g (40 mmol) o-Tol3Sb was added
to a solution of l.84 g (80 mmol) Na in 150 ml liquid
NH3 at −70 °C and the mixture was stirred for 1.5 h.
The solution became dark red and 7.49 g (40 mmol)
BrCH2CH2Br was added dropwise through a syringe.
After stirring for 1 h NH3 was allowed to evaporate.
The remaining yellow solid was washed with 150 ml
water, dried at reduced pressure and dissolved in 100
ml Et2O. Cooling the yellow solution to −23 °C gave
3.46 g (28.5%) yellow crystals of o-Tol4Sb2 (m.p.
158 °C). 1H-NMR (CDCl3): l=2.48 (s, 3H, CH3)
7.05–7.24, 7.39–7.41 (m, 4H, C6H4). MS (70 eV), m/z
(%): 607 (45) [M+], 303 (95) [Tol2Sb+], 182 (100)
[Tol+2 ]. Anal. Found: C, 55.72; H, 4.72. Calc. for
C28H28Sb2: C, 55.31; H, 4.64%. (b) p-Tol4Sb2: the
analogous procedure with 15.8 g p-Tol3Sb gave 3.82 g
(31.5%) yellow p-Tol4Sb2 (m.p. 155 °C). 1H-NMR
(CDCl3): l=2.36 (s, 3H, CH3), 7.20–7.27, 7.43–7.49
(AA%XX% spin system, 4H, C6H4). MS (70 eV), m/z (%):
607 (52) [M+], 303 (100) [Tol2Sb+], 182 (90) [Tol+2 ].
Anal. Found: C, 54.18; H, 4.56. Calc. for C28H28Sb2: C,
55.31; H, 4.64%.
1
sources for O2 have not yet been successful.
3.2. Synthesis of bis(diarylantimony)oxides
(a) (Ph2Sb)2O: A solution of 2.00 g (3.63 mmol)
Ph4Sb2 in 100 ml Et2O was exposed to the air until the
yellow colour of the distibane had almost disappeared.
Removal of the solvent at reduced pressure gave 1.93 g
(94%) (Ph2Sb)2O as a colourless solid. Single crystals
(m.p. 78 °C, Ref. [1]: 78–81 °C) were grown from a
solution in Et2O exposed to the atmosphere at room
1
temperature. H-NMR (CDCl3): l=7.40–7.45 (m, 3H,
C6H5), 7.61–7.66 (m, 2H, C6H5). MS data as reported
in Ref. [1]. (b) (o-Tol2Sb)2O: the analogous reaction of
2.00 g (3.29 mmol) o-Tol4Sb2 in 100 ml Et2O gave 1.98
g (96%) of white solid (o-Tol2Sb)2O (m.p. 109 °C).
Single crystals were grown in toluene at −23 °C.
1H-NMR (CDCl3): l=2.25 (s, 3H, CH3) 7.06–7.25,
7.58–7.65 (m, 4H, C6H4), MS (70 eV); m/z (%): 624
(96) [M+], 533 (43) [M+−Tol], 441 (10) [M+−2Tol],
303 (56), 212 (39) 181 (95), 91(100). (c) p-Tol4Sb2O: the
air oxidation of 2.00 g (3.29 mmol) p-Tol4Sb2 in 100 ml
Et2O gave 2.05 g (100%) of white solid (p-Tol2Sb)2O
(m.p. 101 °C, Ref. [3]: 101 °C). Single crystals were
Fig. 2. Two views on the structure of (Ph2SbO)4(O2)2, (below: O(2),
O(4) and O(6), O(8) are in ecliptic positions) distances (pm) and
angles (°): SbꢀO(O) 220.5(3)–225.1(3), SbꢀC 210.3(5)–212.4(5),
SbꢀO(Sb) 194.6(3)–197.6(3), O(5)ꢀO(7) 146.1(4), O(6)ꢀO(8) 146.6(5);
SbꢀO(Sb)ꢀSb 110.89(1)–111.91(1), SbꢀO(O)ꢀSb 92.9(1)–93.54(1),
SbꢀO(O)ꢀO(O) 112.8(2)–114.2(2), O(O)ꢀSbꢀO(O) 74.51(1)–74.91(1),
CꢀSbꢀC 105.8(2)–108.1(2). O(Sb)ꢀSbꢀO(Sb) 153.96(1)–154.61(1),
O(Sb)ꢀSbꢀC 92.6(2)–103.6(2), O(Sb)ꢀSbꢀO(O) 74.13(1)–75.26(1),
O(O)ꢀSbꢀC 87.5(1)–91.9(2), O(Sb)ꢀSbꢀO(O) 83.95(1)–85.51(1),
O(O)ꢀSbꢀC 159.6(2)–164.8(2).
1
grown in toluene at −23 °C. H-NMR (CDCl3): l=
2.33 (s, 3H, CH3) 7.10–7.17, 7.38–7.42 (AA%XX% spin

H.J. Breunig et al. / Journal of Organometallic Chemistry 648 (2002) 209–213
213
system, 4H, C6H4). MS (70 eV); m/z (%): 624 (54)
[M+], 533 (42), 442 (83), 394 (41), 303 (83), 212 (87),
182 (100), 91(82).
Tol2SbO)4(O2)2: 3.94 g (3.0 mmol) (p-Tol2Sb)4O6 in 100
ml Et2O and 100 ml of a 30% aqueous solution (0.98
mol) of H2O2 reacted to give 3.72 g (92.4%) (p-
Tol2SbO)4(O2)2 as
a white powder (m.p. (dec.),
1
281 °C). H-NMR (C6D6): l=1.92 (s, 3H, CH3), 6.8–
6.9, 8.0–8.1 (m, 4H, C6H4). MS (DCl pos., NH3); m/z
(%): 1345 (100) [M++H]. Anal. Found: C, 51.02; H,
4.76. Calc. for C56H56O8Sb4: C, 50.04; H, 4.20%.
3.3. Synthesis of tetrakis(diarylantimony)hexoxides by
the oxidation of distibanes
(a) (Ph2Sb)4O6: 3.00 g (5.44 mmol) Ph4Sb2 was dis-
solved in 150 ml Et2O and a gentle flow of dry air was
passed through the solution until the yellow colour of
the solution disappeared and the precipitation of a
white solid was completed. Washing of the precipitate
with Et2O and removal of the solvent at reduced pres-
sure gave 3.13 g (95.9%) (Ph2Sb)4O6 as white solid
powder (m.p. 280 °C, Ref. [6]: 285–290 °C). EIMS
(280 °C, 70 eV); m/z (%): 1123 (2) [M+−Ph], 429 (8),
352 (10), 275 (19), 198 (81), 154 (100), 77 (43) Ph; MS
(DCI neg., NH3); m/z (%): 1223 (100) [M−−Ph], 1047
(41). (b) (o-Tol2Sb)4O6: 3.00 g (4.93 mmol) o-Tol4Sb2
reacted with air in an analogous procedure to give 3.01
g (93.0%) (o-Tol2Sb)4O6 as a white powder (m.p.
266 °C). MS (DCl neg., NH3) m/z (%): 1221 (100)
[M−−Tol], 395 (76), 319 (25). Anal. Found: C, 51.26;
H, 3.62. Calc. for C56H56O6Sb4: C, 51.26; H, 4.30%. (c)
(p-Tol2Sb)4O6: 3.00 g (4.93 mmol) p-Tol4Sb2 was re-
acted with air in 150 ml of Et2O to give 3.05 g (94.4%)
(p-Tol2Sb)4O6 as white solid powder (m.p. 280 °C). MS
(DCl neg., NH3) m/z (%): 1221 (100) [M+−Tol], 395
(28), 319 (55), 303 (5). Anal. Found: C, 50.87; H, 4.07.
Calc. for C56H56O6Sb4: C, 51.26; H, 4.30%.
4. Supplementary material
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC nos. 168018, 168015–168017 for
(Ph2Sb)2O, (o-Tol2Sb)2O, (p-Tol2Sb)2O, (Ph2SbO)4-
(O2)2, respectively. 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).
Acknowledgements
We thank Mrs Lucia Bala´zs for helpful discussions.
Financial support by the Universita¨t Bremen is grate-
fully acknowledged.
References
3.4. Synthesis of
tetrakis(diarylantimony)di-v4-peroxo-tetroxides
[1] M. Wieber, Gmelin Handbook of Inorganic Chemistry, Sb
Organoantimony Compounds, Part 2, eighth ed., Springer,
Berlin, 1981.
(a) (Ph2SbO)4(O2)2: 100 ml of a 30% aqueous solu-
tion (0.98 mol) of H2O2 was added to a suspension of
3.60 g (3.0 mmol) (Ph2Sb)4O6 in 100 ml Et2O and the
mixture was stirred for 4 h. Washing the precipitate
with water and Et2O and drying under reduced pressure
gave 3.37 g (91.3%) (Ph2SbO)4(O2)2 as white powder
(m.p. (dec.) 293 °C). Single crystals were obtained from
[2] G.T. Morgan, G.R. Davies, Proc. R. Soc. Ser. A 110 (1926) 523.
[3] F.F. Blicke, U.O. Oakdale, F.D. Smith, J. Am. Chem. Soc. 53
(1931) 1025.
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1
a solution in toluene at −23 °C after 2 months. H-
NMR (C6D6): l=6.97–7.03 (m, 3H), 8.02–8.08 (m,
2H) MS (DCl pos., NH3); m/z (%): 1233 (100) [M++
H]. Anal. Found: C, 46.44; H, 3.63. Calc. for
C48H40O8Sb4: C, 46.80; H, 3.27%. (b) (o-Tol2Sb)4O6:
3.94 g (3.0 mmol) (o-Tol2Sb)4O6 in 100 ml Et2O and
100 ml of a 30% aqueous solution (0.98 mol) of H2O2
reacted to give 3.78 g (93.7%) (o-Tol2SbO)4(O2)2 as
1
white powder (m.p. (dec.) 273 °C). H-NMR (C6D6):
3
3
l=2.45 (s, 3H), 6.75 (t, J=3 Hz, 1H), 6.92 (d, J=8
3
3
Hz, 1H), 7.00 (t, J=3 Hz, 1H), 7.93 (d, J=8 Hz,
1H). MS (DCl pos., NH3); m/z (%): 1345 (100) [M++
H]. Anal. Found: C, 50.39; H, 4.70. Calc. for
C56H56O8Sb4: C, 50.04; H, 4.20%. (c) (p-