Polyhedral antimony(III) and bismuth(III) siloxanes: Synthesis, spectral studies, and structural characterization of [Sb(O3SiR)]4 and [Bi12(O3SiR)8(μ3-O)4Cl4(THF)8] (R = (2,6-iPr2C6H3)N(SiMe3))

Article abstract of DOI:10.1016/j.ica.2005.12.005

The antimony(III) and bismuth(III) containing siloxanes [Sb(O₃SiR)]₄ (2) and [Bi₁₂(O₃SiR)₈(μ₃-O)₄Cl₄(THF)₈] (3) (R = (2,6-iPr₂C₆H₃)N(SiMe₃)) have been prepared by the reaction of lipophilic N-bonded silanetriol 1 with the corresponding metal amides M(NMe₂)₃ (M = Sb, Bi). The composition and molecular structures of 2 and 3 have been fully determined by mass spectrometry, IR, NMR spectroscopy, elemental analysis, and lower temperature X-ray crystal structural analyses. Compound 2 represents the first example of a structurally characterized cubic antimony(III) containing siloxane ligands, whereas compound 3 exhibits a new highly soluble bismuth(III) cluster containing chloride and siloxane ligands. Hydrophobic groups, surrounding the central Si₄O₁₂Sb₄ and Bi₁₂Cl₄O₂₈Si₈ cores, play an important role in the high solubility of compounds 2 and 3 in common organic solvents. Several attempts to assemble the analogous bismuth(III) containing chloride free siloxane cluster were not successful. In our hands only the chlorine containing cluster resulted in the formation of single crystals.

Full text of DOI:10.1016/j.ica.2005.12.005

Inorganica Chimica Acta 360 (2007) 1248–1257
www.elsevier.com/locate/ica
Polyhedral antimony(III) and bismuth(III) siloxanes: Synthesis,
spectral studies, and structural characterization of [Sb(O3SiR)]4
and [Bi12(O3SiR)8(l3-O)4Cl4(THF)8] (R = (2,6-iPr2C6H3)N(SiMe3))
*
Umesh N. Nehete, Herbert W. Roesky , Vojtech Jancik, Aritra Pal, Jorg Magull
¨
Institut fu¨r Anorganische Chemie der Georg-August Universita¨t Go¨ttingen, Tammannstrasse 4, 37077 Go¨ttingen, Germany
Received 23 August 2005; accepted 4 December 2005
Available online 26 January 2006
Dedicated to Professor M.F. Lappert.
Abstract
The antimony(III) and bismuth(III) containing siloxanes [Sb(O3SiR)]4 (2) and [Bi12(O3SiR)8(l3-O)4Cl4(THF)8] (3) (R = (2,6-
iPr2C6H3)N(SiMe3)) have been prepared by the reaction of lipophilic N-bonded silanetriol 1 with the corresponding metal amides
M(NMe2)3 (M = Sb, Bi). The composition and molecular structures of 2 and 3 have been fully determined by mass spectrometry,
IR, NMR spectroscopy, elemental analysis, and lower temperature X-ray crystal structural analyses. Compound 2 represents the first
example of a structurally characterized cubic antimony(III) containing siloxane ligands, whereas compound 3 exhibits a new highly sol-
uble bismuth(III) cluster containing chloride and siloxane ligands. Hydrophobic groups, surrounding the central Si4O12Sb4 and
Bi12Cl4O28Si8 cores, play an important role in the high solubility of compounds 2 and 3 in common organic solvents. Several attempts
to assemble the analogous bismuth(III) containing chloride free siloxane cluster were not successful. In our hands only the chlorine con-
taining cluster resulted in the formation of single crystals.
Ó 2005 Elsevier B.V. All rights reserved.
Keywords: Cage compounds; Silanetriol; Antimonysiloxane; Bismuthsiloxane; Silicon
1. Introduction
zeolites. Furthermore, these compounds are quite valuable
in understanding the reaction path and the intermediate
steps formed during the catalytic processes, particularly
those involving silica supported transition metal catalysts
[8]. We have, for example, shown that cubic titanasiloxanes
[RSiO3TiR1]4 [R = (2,6-iPr2C6H3)N(SiMe3)] [R1 = Et, iPr]
apart from being good models for titanium containing zeo-
lites such as TS-1 and TS-2, are also good catalysts, espe-
cially for epoxidation of cyclo-hexene and cyclo-octene
[9]. Moreover, the metallasiloxanes can also be considered
as precursors for silicon polymers containing metal centers
in the polymeric backbone [10].
There has been recently great interest in the synthesis
and characterization of metallasiloxanes containing the
Si–O–M motif (M = main group or transition metal) [1–
3], although the first reports date back to the end of the
19th century [4]. The soluble metallasiloxanes derived from
–SiOH groups indeed act as structural model compounds
for the heterogeneous metal incorporated zeolites [5]. The
core structures of the Group 13 [6] and titanium [7] con-
taining cubic metallasiloxanes act as the secondary build-
ing blocks (SBU) of Group 13 and titanium containing
In view of the importance of such compounds, we have
been actively involved in the synthesis of metallasiloxanes
starting from lipophilic N-bonded silanetriol RSi(OH)3
(R = (2,6-iPr2C6H3)N(SiMe3)) (1) with metal alkyls, metal
*
Corresponding author. Tel.: +49 551 393001; fax: +49 551 393373.
E-mail address: hroesky@gwdg.de (H.W. Roesky).
0020-1693/$ - see front matter Ó 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2005.12.005

U.N. Nehete et al. / Inorganica Chimica Acta 360 (2007) 1248–1257
1249
alcoholates, and metal amides as the precursor under the
elimination of alkanes, alcohols, and amines, respectively
[1a–i]. Among them, compounds with a cubic core struc-
ture are of particular interest [6,7,11]. In this direction,
we synthesized a range of Al-, Ge-, In-, Ge-, Sn- Ti-, Fe-,
and Zn-containing siloxanes with cubic M4O12Si4 frame-
works. With this in mind, it was of interest to extend our
studies towards the preparation of soluble analogous
molecular antimony(III), and bismuth(III) containing
siloxane frameworks. Previously, Schmidbaur [12a,12b]
and Hubert-Pfalzgraf et al. [13a] have reported on anti-
mony(III), and bismuth(III) containing siloxane com-
pounds which were obtained by use of R3SiO. Feher
et al. synthesized cubic Group 15 containing hetero-
silsesquioxanes by the ‘‘corner-capping’’ reaction starting
from three-functional, incompletely condensed oli-
gosilsesquioxanes (c-C6H11)7Si7O9(OH)3 [14a], those struc-
tures could not be completely solved except the phosphorus
congener. However, these compounds have a metal/silicon
ratio of 1:7 [14]. Recently, Mehring et al. reported on a
polyhedral bismuth siloxane of composition [Bi22O26(OSi-
Me2tBu)14] [13d,13e].
In this paper, we present the synthesis, spectral studies,
and structural characterization of the [Sb(O3SiR)]4 (2) and
[Bi12(O3SiR)8(l3-O)4Cl4(THF)8] (3) (R = (2,6-iPr2C6H3)N-
(SiMe3)). These compounds have the Sb/Si and Bi/Si ratios
of 4:4 and 12:8, respectively. Compound 2 represents the
first example of fully characterized cubic antimony(III)
containing siloxane ligands. More recently, the antimony
silicate (Sb/Si molar ratio of 1:1) has been found to be use-
ful as a high selective ion exchanger for the removal of 85Sr
from nuclear waste solutions [15], whereas bismuth silicate,
as an anion exchanger [16], has been used as a novel sor-
bent in thin layer chromatography [17]. Furthermore, anti-
mony and bismuth silicate glasses find a number of
industrial and special applications such as, fiber optic
amplifiers [18], high temperature superconductors, and
capacitor layers in memory devices [19].
2. Results and discussion
2.1. Synthesis and spectroscopic characterization of
compound 2
The reaction of (arylamino) silanetriol [20] RSi(OH)3
(R = (2,6-iPr2C6H3)N(SiMe3)) (1) with antimony(III)
amide [21] Sb(NMe2)3 in hexane and THF at room temper-
ature with a 1:1 stoichiometric ratio afforded the cuboid
antimony(III) siloxane [Sb(O3SiR)]4 (R = (2,6-iPr2C6H3)-
N(SiMe3)) (2) in about 83% yield (Scheme 1).
The reaction proceeds under evolution of dimethyl-
amine HNMe2, which results in the subsequent assembly
of the three-dimensional Si–O–Sb frameworks. Compound
2 is highly soluble in common organic solvents such as hex-
ane, benzene, toluene, ether or THF. Compound 2 has
been fully characterized by means of analytical, spectro-
scopic, and single-crystal X-ray diffraction studies. An
interesting aspect of the antimony(III) siloxane 2 is that,
in spite of the large molecular weight, the electron impact
mass spectrum (EIMS) of compound 2 reveals a strong
parent molecular ion in the range of m/z 1781–1792
([M+] 1784.2 relative intensity: 100%) that possesses an iso-
topic cluster pattern that is also consistent with the
expected composition as shown in Fig. 1. This observation
indicates that, under ionization conditions (70 eV), the
cubic core of compound 2 remains intact. Besides this,
compound 2 does not melt up to 387°C, at which point
the color of the compound turns into black brown. The
IR spectrum of compound 2 shows an absorption between
900 and 1000 cmꢀ1, which could be attributed to Si–O–Sb
R
Si
O
O
O
O
O
Sb
Sb
O
Sb(NMe2)3
O
Si
O
R
4:4
-12 HNMe2
Sb
O
Si
O
Sb
R
Si
O
R
O
2
hexane/THF
RSi(OH)3
S
R
R
1
Bi
O
4 H2O
O
O
Cl
Bi
S
Si
R = (2,6-iPr2C6H3)N(SiMe3)
Si
O
O
Bi(NMe2)3
Bi(NMe2)2Cl
R
Si
O
Bi
O
O
O
R
O
S
O
Si
O
O
S
Bi
S
O
Bi
Cl
Bi
O
O
8:8:4
-32 HNMe2
S = THF
O
Bi
O
R
O
Cl
Bi
Bi
Si
O
O
O
R
Si
Bi
Cl
O
O
S
O
Bi
Bi
O
Si
Si
O
S
O
R
S
R
3
Scheme 1. Synthesis of compounds 2 and 3.

1250
U.N. Nehete et al. / Inorganica Chimica Acta 360 (2007) 1248–1257
Fig. 1. (a) A partial mass spectrum (electron impact) of 2 showing the parent ion in the m/z 1781 to 1792 range. (b) A simulated isotope cluster pattern
expected for the C60H104N4O12Sb4Si8 composition.
stretching frequency. The 1H NMR spectral data (in C6D6)
and the integration of the intensities match well with the
proposed structure of compound 2. The protons from the
–SiMe3 groups resonate as a singlet (d = 0.25 ppm). Two
sets of doublets of equal intensity appear at d = 1.23 and
1.26 ppm (J = 6.9 Hz) for the two isopropyl methyl
3 are listed in Table 1. Selected metric parameters of 2
are summarized in Table 2. The ORTEP core structure dia-
grams of both independent molecules of 2 are shown in
Fig. 2. The Si4O12Sb4 core structure can be defined by four
silicon and four antimony atoms occupying alternate cor-
ners of the distorted cubic polyhedron. Each of the 12
Siꢁ ꢁ ꢁSb edges is bridged by oxygen atoms in a l-bridging
fashion. There are six Si2O4Sb2 eight-membered rings that
define the faces of the cube, and each of these rings adopts
a pseudo C4 crown conformation.
It is interesting to note that none of the antimony atoms
have any other ligands in their coordination environment
except oxygen. The antimony atoms adopt distorted trigo-
nal pyramidal geometry. The warped form of the trigonal
pyramidal geometry may be attributed to the lone pair
repulsions. The O–Sb–O angles are observed in the range
from 91.1(1)° [O(4)–Sb(3)–O(7)] to 100.4(1)° [O(3)–Sb(1)–
O(6)] with the average angle of 95.6°. This value compares
well with the data reported for [Sb(OSiMe3)3] [12a] av.
95.2°. However, the silicon atom shows nearly ideal tetra-
hedral geometry. The O–Si–O angles are observed in the
range from 108.0(2)° [O(20)–Si(13)–O(19)] to 112.8(2)°
[O(10)–Si(1)–O(12)] with an average angle of 109.7°.
The Sb–O bond distances in 2 vary in the range of
(CH(CH3)2) protons, while
a septet (d = 3.75 ppm,
J = 6.9 Hz) is observed for the isopropyl methine
(CH(CH3)2) proton. The appearance of two different reso-
nances for isopropyl groups is consistent with the crystal
structure of 2 if the rotation of the aromatic groups about
the C–N bond is restricted. The aryl protons of compound
2 resonate as a multiplet in the range of d = 6.66–6.69 ppm.
The 29Si NMR spectrum of compound 2 (in C6D6) displays
two single resonances for the Me3SiN unit (d = 4.4 ppm)
and for the O3SiN part (d = ꢀ91 ppm), indicating a high
symmetry in solution.
2.2. Structural description of 2
Unequivocal proof of the structure for compound 2 has
been provided by the crystallographic analysis of single
crystals. Single crystals of 2 suitable for X-ray structural
determination were grown from their concentrated hex-
ane/THF solution. Compound 2 crystallizes in the mono-
clinic space group P21/n, along with two independent
molecules and 2.68 molecules of THF in the asymmetric
unit. The structure refinement data of compounds 2 and
˚
˚
1.914(3) A [Sb(7)–O(17)] to 1.955(3) A [Sb(5)–O(19)] with
˚
an average value of 1.940 A. These are slightly longer than
the corresponding ones found for [Sb(OSiMe3)3] [12a] (av.
˚
1.935 A). The Si–O bond distances are seen in the range of

U.N. Nehete et al. / Inorganica Chimica Acta 360 (2007) 1248–1257
1251
Table 1
Crystal data and structure refinement for compounds 2 and 3
2 Æ 1.34C4H8O
65.37H114.73N4O13.34Sb4Si8
1881.92
monoclinic
P21/n
100(2)
1.54178
27.075(6)
14.923(4)
41.644(10)
90
94.93(3)
90
16764(7)
8
3 Æ 2C4H8O
Formula
C
C160H288Bi12Cl4N8O38Si16
6030.98
monoclinic
P21/n
Formula weight
Crystal system
Space group
T (K)
133(2)
˚
k (A)
0.71073
22.9236(7)
19.0353(5)
23.7193(8)
90
94.025(3)
90
10324.6(5)
2
˚
a (A)
˚
b (A)
˚
c (A)
a (°)
b (°)
c (°)
3
˚
V (A )
Z
qcalc (g/cm3)
1.491
11.666
7661
1.940
10.396
5792
l (mmꢀ1
F(000)
)
h Range for data collection (°)
Index ranges
1.02–29.52
1.28–24.36
ꢀ26 6 h 6 30, ꢀ16 6 k 6 16, ꢀ41 6 l 6 43
ꢀ26 6 h 6 26, ꢀ22 6 k 6 21, ꢀ27 6 l 6 27
Number of reflections collected
Number of independent reflections (Rint
Number of data/restraints/parameters
Goodness-of-fit on F2
118007
54953
)
23725 (0.0797)
23725/2690/2075
1.003
0.0367, 0.0681
0.0627, 0.0764
0.742/ꢀ0.624
16691 (0.0672)
16691/0/1025
1.021
0.0329, 0.0681
0.0483, 0.0772
1.589/ꢀ1.196
R1,a wR2 (I > 2r(I))
b
R1,a wR2 (all data)
b
ꢀ3
˚
Largest difference peak/hole (e A
)
P
P
a
R ¼ jjF oj ꢀ jF cjj= jF oj.
P
P
2
2 1=2
b
wR2 ¼ ½ wðF 2o ꢀ F c2Þ = wðF 2oÞ ꢂ
.
˚
˚
1.595(4) A [Si(5)–O(7)] to 1.638(4) A [Si(1)–O(2)] with an
the bismuth(III) amide in our hands was more or less con-
taminated with chloride. Thus, the overall synthesis of
˚
average value of 1.62(4) A, similar to the reported data
found in [RSiO3Al Æ THF]4 (R = (2,6-iPr2C6H3)N(SiMe3))
[6c]. The distortion of the cube is indicated by the broad
range of the Sb–O–Si angles. Thus, the Sb–O–Si angles
within the framework are in the range of 128.9(2)° [Si(5)–
O(8)–Sb(4)] to 158.1(2)°
142.5°).
[Bi12(O3SiR)8(l3-O)4Cl4(THF)8]
(R = (2,6-iPr2C6H3)N-
(SiMe3)) (3) involves, eight molecules of silanetriol, eight
molecules of Bi(NMe2)3, four molecules of Bi(NMe2)2Cl,
and four molecules of water under elimination of 32 mole-
cules of HNMe2.
1 [Si(13)–O(20)–Sb(8)] (av.
Compound 3 has been characterized based on its analyt-
ical, spectroscopic, and mass spectrometric data. Interest-
ingly, compound 3 does not melt up to 398 °C and
decomposes without melting on further heating. However,
no peak attributable to the molecular ion of 3 can be
observed in the EI or other mass spectrometric methods.
Only smaller fragment ion peaks are found. Similar to com-
pound [Bi22O26(OSiMe2tBu)14] [13d,13e], compound 3 is
also good soluble in common hydrocarbon solvents, such
as benzene. Like 2, 3 also shows the absence of a character-
istic strong broad IR absorption centered around
3400 cmꢀ1, indicating that all of the Si–OH groups of 1 have
reacted and the IR spectrum is dominated by the typical M–
O–Si stretching frequencies observed in the range of 900–
1000 cmꢀ1. It is difficult to deduce the structure of compound
3 as its 1H NMR spectrum (in C6D6) revealed several multi-
ple resonances for the methyl (SiMe3, and iPr), isopropyl –
CH, aryl protons, and (slightly broad) coordinated THF
molecule protons. Nevertheless, the 29Si NMR spectrum of
compound 3 (in C6D6) displays the presence of six reso-
nances, out of which the first three are assigned for the
2.3. Synthesis and spectroscopic characterization of
compound 3
Compound 3 is synthesized by the addition of a hexane
solution of bismuth(III) amide [22] to a suspension of
RSi(OH)3 (R = (2,6-iPr2C6H3)N(SiMe3)) (1) in 1:1 molar
ratio, at room temperature, in about 23% yield (Scheme
1). The formation of 3 proceeds with the evolution of dim-
ethylamine gas and a self-condensation of the silanetriol to
generate the disiloxanetetrol [(RSi(OH)2)2O] and water.
This process is presumably catalyzed by bismuth(III)
amide. Such a condensation reaction has been noted by
us earlier in the presence of hydrazine [23]. Furthermore,
during the course of the reaction, two molecules of dimeth-
ylamine are eliminated, resulting in the capping of the three
Bi(III) centers by the oxygen of liberated water molecule.
The yield of 3 highly depends on the chloride containing
bismuth(III) amide. For the preparation of bismuth(III)
amide [22] we followed the literature method. However,

1252
U.N. Nehete et al. / Inorganica Chimica Acta 360 (2007) 1248–1257
Table 2
˚
Selected bond lengths (A) and bond angles (°) for compounds 2 and 3
Compound 2 Æ 1.34THF
Molecule 1
Sb(1)–O(3)
Sb(1)–O(6)
Sb(1)–O(9)
Sb(2)–O(2)
Sb(2)–O(5)
Sb(2)–O(10)
Sb(3)–O(4)
Sb(3)–O(7)
1.954(3)
1.952(4)
1.951(3)
1.943(3)
1.917(3)
1.951(3)
1.945(3)
1.931(3)
Sb(3)–O(11)
Sb(4)–O(8)
Sb(4)–O(12)
Sb(4)–O(1)
Si(1)–O(1)
Si(1)–O(2)
Si(1)–O(3)
Si(3)–O(4)
1.951(3)
1.949(3)
1.953(3)
1.919(3)
1.603(4)
1.638(4)
1.621(4)
1.632(4)
Si(3)–O(5)
Si(3)–O(6)
Si(5)–O(7)
Si(5)–O(8)
Si(5)–O(9)
Si(7)–O(10)
Si(7)–O(11)
Si(7)–O(12)
1.602(4)
1.619(4)
1.595(4)
1.630(4)
1.625(4)
1.624(4)
1.629(4)
1.616(4)
O(9)–Sb(1)–O(6)
O(9)–Sb(1)–O(3)
O(6)–Sb(1)–O(3)
O(5)–Sb(2)–O(2)
O(5)–Sb(2)–O(10)
O(2)–Sb(2)–O(10)
O(7)–Sb(3)–O(4)
O(7)–Sb(3)–O(11)
O(4)–Sb(3)–O(11)
O(1)–Sb(4)–O(8)
O(1)–Sb(4)–O(12)
O(8)–Sb(4)–O(12)
98.4(1)
99.3(1)
100.4(1)
92.3(1)
93.7(1)
96.7(1)
91.1(1)
93.1(1)
97.8(1)
92.1(1)
92.6(1)
98.0(1)
O(1)–Si(1)–O(3)
O(1)–Si(1)–O(2)
O(3)–Si(1)–O(2)
O(5)–Si(3)–O(6)
O(5)–Si(3)–O(4)
O(6)–Si(3)–O(4)
O(7)–Si(5)–O(9)
O(7)–Si(5)–O(8)
O(9)–Si(5)–O(8)
O(12)–Si(7)–O(10)
O(12)–Si(7)–O(11)
O(10)–Si(7)–O(11)
108.3(2)
Si(1)–O(1)–Sb(4)
Si(1)–O(2)–Sb(2)
Si(1)–O(3)–Sb(1)
Si(3)–O(4)–Sb(3)
Si(3)–O(5)–Sb(2)
Si(3)–O(6)–Sb(1)
Si(5)–O(7)–Sb(3)
Si(5)–O(8)–Sb(4)
Si(5)–O(9)–Sb(1)
Si(7)–O(10)–Sb(2)
Si(7)–O(11)–Sb(3)
Si(7)–O(12)–Sb(4)
157.3(2)
109.5(2)
110.0(2)
108.7(2)
108.9(2)
110.4(2)
108.9(2)
109.3(2)
109.7(2)
112.8(2)
109.7(2)
110.8(2)
129.1(2)
143.2(2)
129.2(2)
156.7(2)
141.3(2)
154.2(2)
128.9(2)
140.9(2)
142.3(2)
141.4(2)
142.0(2)
Molecule 2
Sb(5)–O(18)
Sb(5)–O(19)
Sb(5)–O(23)
Sb(6)–O(13)
Sb(6)–O(21)
Sb(6)–O(24)
Sb(7)–O(14)
Sb(7)–O(17)
1.947(3)
1.955(3)
1.943(3)
1.944(3)
1.949(3)
1.923(3)
1.949(3)
1.914(3)
Sb(7)–O(22)
Sb(8)–O(15)
Sb(8)–O(16)
Sb(8)–O(20)
Si(15)–O(22)
Si(15)–O(23)
Si(15)–O(24)
Si(9)–O(13)
1.946(3)
Si(9)–O(14)
Si(9)–O(15)
Si(11)–O(16)
Si(11)–O(17)
Si(11)–O(18)
Si(13)–O(19)
Si(13)–O(20)
Si(13)–O(21)
1.634(4)
1.945(3)
1.950(3)
1.920(3)
1.632(3)
1.630(4)
1.600(3)
1.625(3)
1.628(4)
1.632(3)
1.604(4)
1.629(4)
1.626(3)
1.602(3)
1.633(4)
O(23)–Sb(5)–O(18)
O(23)–Sb(5)–O(19)
O(18)–Sb(5)–O(19)
O(24)–Sb(6)–O(13)
O(24)–Sb(6)–O(21)
O(13)–Sb(6)–O(21)
O(17)–Sb(7)–O(22)
O(17)–Sb(7)–O(14)
O(22)–Sb(7)–O(14)
O(20)–Sb(8)–O(15)
O(20)–Sb(8)–O(16)
O(15)–Sb(8)–O(16)
99.1(1)
99.8(1)
99.9(1)
93.5(1)
91.9(1)
96.1(1)
91.8(1)
93.1(1)
99.1(1)
93.5(1)
92.5(1)
97.3(1)
O(13)–Si(9)–O(15)
O(13)–Si(9)–O(14)
O(15)–Si(9)–O(14)
O(17)–Si(11)–O(18)
O(17)–Si(11)–O(16)
O(18)–Si(11)–O(16)
O(20)–Si(13)–O(19)
O(20)–Si(13)–O(21)
O(19)–Si(13)–O(21)
O(24)–Si(15)–O(23)
O(24)–Si(15)–O(22)
O(23)–Si(15)–O(22)
112.4(2)
Si(9)–O(13)–Sb(6)
Si(9)–O(14)–Sb(7)
Si(9)–O(15)–Sb(8)
Si(11)–O(16)–Sb(8)
Si(11)–O(17)–Sb(7)
Si(11)–O(18)–Sb(5)
Si(13)–O(19)–Sb(5)
Si(13)–O(20)–Sb(8)
Si(13)–O(21)–Sb(6)
Si(15)–O(22)–Sb(7)
Si(15)–O(23)–Sb(5)
Si(15)–O(24)–Sb(6)
142.8(2)
110.5(2)
110.0(2)
108.8(2)
109.3(2)
110.0(2)
108.0(2)
109.6(2)
110.1(2)
108.2(2)
108.7(2)
110.3(2)
141.9(2)
141.1(2)
129.5(2)
157.2(2)
143.1(2)
143.5(2)
158.1(2)
129.4(2)
130.4(2)
141.4(2)
155.6(2)
Compound 3
Bi(1)–O(1)
Bi(1)–O(13)
Bi(1)–O(7)
Bi(1)–O(4)
Bi(1)–O(2L)
Bi(2)–O(2)
Bi(2)–O(13)
Bi(2)–O(10)
Bi(2)–O(7)
Bi(3)–O(3)
Bi(3)–O(13)
Bi(3)–O(4)
Bi(3)–O(10)
Bi(3)–O(15)
Bi(4)–O(8)
Bi(4)–O(5)
Bi(4)–O(14)
Bi(4)–O(3L)
2.068(5)
O(1)–Bi(1)–O(13)
O(1)–Bi(1)–O(7)
O(13)–Bi(1)–O(7)
O(1)–Bi(1)–O(4)
O(13)–Bi(1)–O(4)
O(1)–Bi(1)–O(2L)
O(13)–Bi(1)–O(2L)
O(7)–Bi(1)–O(2L)
O(4)–Bi(1)–O(2L)
O(2)–Bi(2)–O(13)
O(2)–Bi(2)–O(10)
O(13)–Bi(2)–O(10)
O(2)–Bi(2)–O(7)
O(13)–Bi(2)–O(7)
O(3)–Bi(3)–O(13)
O(3)–Bi(3)–O(4)
O(13)–Bi(3)–O(4)
O(3)–Bi(3)–O(10)
89.8(2)
91.4(2)
71.74(18)
91.3(2)
67.71(17)
80.4(2)
159.9(2)
125.7(2)
94.8(2)
89.5(2)
89.5(2)
72.51(19)
90.96(19)
68.08(18)
89.3(2)
2.139(5)
2.272(5)
2.476(5)
2.893(7)
2.067(6)
2.149(5)
2.245(5)
2.451(5)
2.086(5)
2.155(5)
2.307(5)
2.512(6)
2.673(7)
2.084(5)
2.100(5)
2.230(5)
2.794(5)
90.9(2)
70.74(18)
89.99(18)

U.N. Nehete et al. / Inorganica Chimica Acta 360 (2007) 1248–1257
1253
Table 2 (continued)
Compound 3
Bi(5)–O(11)
Bi(5)–O(6)
Bi(5)–O(14)
Bi(6)–O(12)
Bi(6)–O(9)
Bi(6)–O(14)
Bi(6)–O(16)
Bi(5)–Cl(2)
Bi(5)–Cl(1)
Bi(6)–Cl(2)
Bi(6)–Cl(1A)
Si(1)–O(2)
Si(1)–O(1)
Si(1)–O(3)
Si(3)–O(6)
Si(3)–O(5)
Si(3)–O(4)
Si(5)–O(9)
Si(5)–O(8)
Si(5)–O(7)
Si(7)–O(11)
Si(7)–O(12)
Si(7)–O(10)
2.115(5)
2.136(5)
2.151(5)
2.102(5)
2.144(5)
2.236(5)
2.698(6)
2.851(2)
2.966(2)
2.885(2)
3.019(2)
1.621(6)
1.626(6)
1.636(6)
1.621(5)
1.633(5)
1.651(5)
1.613(5)
1.621(5)
1.653(6)
1.620(5)
1.632(6)
1.663(5)
O(13)–Bi(3)–O(10)
O(3)–Bi(3)–O(15)
O(4)–Bi(3)–O(15)
O(8)–Bi(4)–O(5)
67.21(17)
80.4(2)
98.8(2)
89.6(2)
O(8)–Bi(4)–O(14)
O(5)–Bi(4)–O(14)
O(8)–Bi(4)–O(3L)
O(5)–Bi(4)–O(3L)
O(14)–Bi(4)–O(3L)
O(11)–Bi(5)–O(6)
O(11)–Bi(5)–O(14)
O(11)–Bi(5)–Cl(2)
O(11)–Bi(5)–Cl(1)
O(6)–Bi(5)–O(14)
O(12)–Bi(6)–O(9)
O(12)–Bi(6)–O(14)
O(12)–Bi(6)–O(16)
O(12)–Bi(6)–Cl(2)
O(12)–Bi(6)–Cl(1A)
O(14)–Bi(6)–Cl(1A)
Cl(2)–Bi(6)–Cl(1A)
Bi(1)–O(13)–Bi(2)
Bi(1)–O(13)–Bi(3)
Bi(2)–O(13)–Bi(3)
Bi(5)–O(14)–Bi(4)
Bi(5)–O(14)–Bi(6)
Bi(4)–O(14)–Bi(6)
89.61(18)
90.43(19)
73.5(2)
76.4(2)
158.4(2)
86.2(2)
93.58(19)
88.86(15)
174.24(15)
90.46(19)
87.5(2)
90.71(19)
75.4(2)
86.35(14)
165.58(14)
76.60(12)
83.95(6)
113.3(2)
114.3(2)
114.0(2)
119.0(2)
116.1(2)
120.1(2)
Fig. 2. ORTEP diagram of cores of the two independent molecules of 2 with 50% probability. Most of the substituents on silicon atoms are omitted for the
sake of clarity.
Me3SiN unit (d = 6.4, 5.5, 2.5 ppm), whereas the rest are
assigned for the O3SiN part (d = ꢀ72.2, ꢀ79.1, ꢀ83 ppm),
indicating that in each Bi6Cl2O14Si4 unit out of four, two sila-
netriol molecules are present in the same electronic environ-
ment. In compounds 2 and 3, the 29Si NMR chemical shifts
for the O3SiN silicon centers are shifted upfield compared
to the values observed in the parent silanetriol
(ꢀ67.3 ppm) [20]. The solid state structure of 3 has been

1254
U.N. Nehete et al. / Inorganica Chimica Acta 360 (2007) 1248–1257
Fig. 3. ORTEP diagram of core 3 with 50% probability. Most of the substituents on silicon and bismuth atoms are omitted for the sake of clarity.
unambiguously established by single-crystal X-ray diffrac-
tion study (Table 1).
Bi3ClO3Si). The l3-bridging oxygens O(13) and O(14) have
markedly pyramidal and distorted trigonal planar
geometries, which can be indicated by the sum of the Bi–
P
2.4. Structural description of 3
O–Bi angles centered around O(13) ( 342°) and O(14)
P
(
355°), respectively. Interestingly, these l3-bridging oxy-
The pale yellow crystals of 3 were obtained from a hex-
ane/THF mixture at room temperature over a period of
two weeks. The ORTEP diagram of 3 is depicted in
Fig. 3. Compound 3 crystallizes in the monoclinic space
group P21/n along with half of the molecule and one mol-
ecule of THF in the asymmetric unit. Selected bond dis-
tances and angles obtained for this compound are listed
in Table 2. The molecular structure of 3 consists of a cen-
trosymmetric Bi12Cl4O28Si8 core. The core structure of 3
contains two Bi6Cl2O14Si4 units that are fused together to
gens lead to the formation of four- (two Bi2O2[Bi(2)–
O(13)–Bi(1)–O(7); Bi(2)–O(13)–Bi(3)–O(10)] around O(13)
and one Bi2ClO [Bi(6)–O(14)–Bi(5)–Cl(2)]), six- (one
Bi2O3Si
[Si(5)–O(8)–Bi(4)–O(14)–Bi(6)–O(9)]
around
O(14), which are fused together to form another
Bi3O3[Bi(2)–O(7)–Bi(1)–O(13)–Bi(3)–O(10)]) and eight-
membered rings (Bi3ClO3Si [Bi(6)–O(9)–Si(5)–O(8)–Bi(4)–
O(14)–Bi(5)–Cl(2)]). As shown in Fig. 3, the coordination
geometry at Bi(1), and Bi(3) may be described as a dis-
torted square pyramid with two silicon bonded l3-bridging
oxygen atoms, one l3-bridging oxygen atom, one coordi-
nated oxygen atom of a THF molecule, and a silicon
bonded l-bridging oxygen. The O–Bi–O angles around
Bi(1) and Bi(3) are in the range of 67.7(2)–159.9(2)° and
67.2(2)–165.3(2)°, respectively, which deviate slightly from
the ideal value of 90°, indicating astereochemically active
lone pair.
generate
a Bi4Cl2O4Si2 [Bi(6)–Cl(1A)–Bi(A5)–O(11A)–
Si(7A)–O(12A)–Bi(6A)–Cl(1)–Bi(5)–O(11)–Si(7)–O(12)] 12-
membered ring (Fig. 2).
Each of these Bi6Cl2O14Si4 units is made up of four-
(two Bi2O2 and one Bi2ClO), six- (seven Bi2O3Si, one
Bi2ClO2Si, one Bi2ClO2Si and one Bi3O3) and eight-mem-
bered rings (three Bi2O4Si2, one Bi3O4Si, and one

U.N. Nehete et al. / Inorganica Chimica Acta 360 (2007) 1248–1257
1255
The coordination environment of Bi(2) is composed of
4. Experimental
three silicon bonded oxygen atoms, and one l3-bridging
oxygen, however the environment around Bi(4) consists of
two silicon bonded oxygens, one l3-bridging oxygen, and
one coordinated oxygen atom of a THF molecule. Both
Bi(2) and Bi(4) are in a distorted tetrahedral geometry.
The O–Bi–O angles around Bi(2) and Bi(4) fall in the range
of 68.1(2) to 140.6(2) and 73.5(2) to 158.4(2) which are
strongly deviate from the ideal tetrahedral values (109.5°).
The Bi(5) adopts a distorted trigonal bipyramidal geometry
with one silicon bonded oxygen, one l3-bridging oxygen,
and one chloride at the equatorial sites and one silicon
bonded oxygen and one chlorine at the apical sites, with
an angle of 174.2(2)°. The rest of the angles at Bi(5) are in
the range of (77.8(1) to 166.95(14)°). The coordination envi-
ronment around Bi(6) is made up of two silicon bonded
oxygens, one l3-bridging oxygen, one coordinated oxygen
of a THF molecule, and two chloride in a distorted octahe-
dral geometry. The O–Bi–Cl axis is quasi-linear (165.6(1)°)
and the corresponding angles centered around Bi(6) are in
the range from 75.4(2) to 163.2(2)°. The O–Si–O angles
are within the range of 105.0(3)–113.3(2)° for [O(6)–Si(3)–
O(4) and O(11)–Si(7)–O(12) av. 108.5°], indicating the
nearly ideal tetrahedral geometry for the silicon atoms.
The Bi–O bond distances in compound 3 vary in the
4.1. General procedure
All experimental manipulations were carried out under a
dry nitrogen atmosphere, rigorously excluding air and
moisture. The samples for spectral measurements were pre-
pared in a drybox. Solvents were purified according to con-
ventional procedures and were freshly distilled prior to use.
Silanetriol [20], Sb(NMe2)3 [21], and Bi(NMe2)3 [22] were
prepared according to the published procedures. Elemental
analyses were performed by the Analytisches Labor des
Instituts fur Anorganische Chemie, der Universita¨t Go¨ttin-
¨
gen. NMR spectra were recorded on Bruker Advance
500 MHz spectrometer. Chemical shifts are reported
in ppm with reference to TMS (1H and 29Si). IR spectra
were obtained on a Bio-Rad FTS-7 spectrometer as nujol
mulls. Mass spectra were recorded on a Finnigan MAT
system 8230 and a Varian MAT CH5 mass spectrometer
by EI-MS methods. Melting points were measured on a
HWS-SG 3000 apparatus and are uncorrected.
4.2. Synthesis and characterization of compound 2
To a stirred suspension of silanetriol (1.4 g, 4.28 mmol)
in hexane (25 mL) and THF (1 mL), liquid Sb(NMe2)3
(1.09 g, 4.28 mmol) was added slowly at room temperature
to produce a homogeneous solution. During the course of
the reaction, evolution of dimethylamine was observed.
The resulting clear solution was stirred for another 24 h
at room temperature and then heated to reflux for 1 h.
The reaction mixture was allowed to cool to room temper-
ature and upon partial removal of the solvent in vacuo a
slight turbid solution was obtained, which disappeared
after gentle warming. The resulting solution was allowed
to crystallize at room temperature to obtain colorless crys-
tals of 2 after 4 days, yield 1.59 g, 83%. M.p. 386–388 °C
˚
range of 2.067(6)–2.893(7) A [Bi(2)–O(2) and Bi(1)–
˚
O(2L)], with an average value of 2.291(7) A. The bond
lengths involving the l3 oxygen centers are at the longer
˚
end of the range (2.139(5)–2.512(6) A) for [Bi(1)–O(13)
˚
and Bi(3)–O(10)] with an average value of 2.277(6) A,
and those to the l oxygen centers are the shortest
˚
2.067(6)–2.144(5) A [Bi(2)–O(2) and Bi(6)–O(9) av.
˚
2.10(6) A]. The average Bi–O bond length in the frame-
˚
work is 2.189(6) A which is remarkably shorter than the
˚
exocyclic Bi–O bond distances of 2.765(7) A. The Si–O
and Bi–Cl bond distances fall in the range of 1.613(5)–
˚
˚
1.663(5) A [Si(5)–O(9) and Si(7)–O(10)] (av. 1.632(6) A)
1
˚
and 2.851(2)–3.019(2) A [Bi(5)–Cl(2) and Bi(6)–Cl(1A) av.
2.93(2) A] (sum of the atomic radii for Bi–Cl 2.87 A) [24],
respectively. Compared with Bi(OSiPh3)3(THF)3, which
shows a Bi–O bond distance of av. 2.495 A, the average
Bi–O distance in 3 is shorter by 0.204 A. These Bi–O bond
(decomp); H NMR (500 MHz, C6D6, TMS): d = 0.25 (s,
˚
˚
36H, Si(CH3)3), 1.23, 1.26 (d, J = 6.9 Hz, 48H, CH(CH3)2),
3.75 (sept, J = 6.9 Hz, 8H, CH(CH3)2), 6.99 (m, 12H, aro-
matic); 29Si NMR (99 MHz, C6D6, TMS): d = 4.4 (SiMe3),
˚
˚
~
and ꢀ91 (SiO3); IR (Nujol, KBr): m ¼ 1364 (m), 1341 (w),
distances can be compared to those reported Bi–O bond
1318 (m), 1259 (m), 1249 (s), 1182 (s), 1106 (m), 1060 (s),
1043 (s), 996 (m), 959 (s), 944 (s), 906 (s), 892 (s), 838 (s),
801 (s), 754 (m), 722 (m), 682 (w), 643 (w), 595 (w), 583
(m), 546 (m), 484 (m), 445 (w), 401 (m) cmꢀ1; EIMS
(70 eV): m/z (%): 1784 (100) [M+]; Elemental analysis (%)
calc. for C60H104N4O12Sb4Si8(1785.19): C, 40.37; H, 5.87;
N, 3.14. Found: C, 39.56; H, 6.26; N, 2.64%.
˚
distances {(av. 2.165 A) for [(tBuPO3H)10(tBuPO3H)2-
˚
Bi14O10 Æ 3C6H6 Æ 4H2O]} [13b], {(av. 2.348 A) for [Bi8(l4–
˚
O)2(l3-O)2(l–OR) (R@OC6F5)]} [13c] and {(av. 2.346 A)
for [Bi22O26(OSiMe2tBu)14]} [13d,13e].
3. Conclusion
In summary, the single-crystal X-ray structure analysis
of the first cubic polyhedral antimony(III) containing silox-
ane 2 is reported. Compound 3 represents an extremely sol-
uble new bismuth(III) cluster containing chloride and
siloxane ligands. In both of these compounds, antimony
and bismuth atoms are in the formal oxidation state of
+III with the M/Si ratio of 4:4 and 12:8, respectively.
4.3. Synthesis and characterization of compound 3
Bi(NMe2)3 (1.46 g, 4.28 mmol) in hexane (10 mL) was
slowly added to a stirred suspension of the silanetriol
(1.4 g, 4.28 mmol) in hexane (10 mL) and THF (3 mL) at
room temperature. During the course of the reaction, evo-
lution of dimethylamine was observed. The resulting clear

1256
U.N. Nehete et al. / Inorganica Chimica Acta 360 (2007) 1248–1257
(d) H.W. Roesky, G. Anantharaman, V. Chandrasekhar, V. Jancik,
S. Singh, Chem. Eur. J. 10 (2004) 4106;
(e) U.N. Nehete, V. Chandrasekhar, G. Anantharaman, H.W.
Roesky, D. Vidovic, J. Magull, Angew. Chem. 116 (2004) 3930;
(f) Angew. Chem., Int. Ed. 43 (2004) 3842;
(g) U.N. Nehete, V. Chandrasekhar, V. Jancik, H.W. Roesky, R.
Herbst-Irmer, Organometallics 23 (2004) 5372;
(h) U.N. Nehete, V. Chandrasekhar, H.W. Roesky, J. Magull,
Angew. Chem. 117 (2005) 285;
(i) Angew. Chem., Int. Ed. 44 (2005) 281;
(j) R. Duchateau, Chem. Rev. 102 (2002) 3525;
(k) H. Schmidbaur, Angew. Chem. 77 (1965) 206;
(l) Angew. Chem., Int. Ed. Engl. 4 (1965) 201;
(m) F. Schindler, H. Schmidbaur, Angew. Chem. 79 (1967) 697;
(n) Angew. Chem., Int. Ed. Engl. 6 (1967) 683.
solution was stirred for another 24 h at r.t. and then heated
to reflux for 1 h. The reaction mixture was allowed to cool
to r.t. and upon partial removal of the solvent in vacuo a
slight turbid solution was obtained, which disappeared
after gentle warming. The resulting solution was allowed
to crystallize at r.t. to obtain pale yellow crystals of 3 after
two weeks, yield 0.71 g, 23%. M.p. >398 °C (decomp); 29Si
NMR (99 MHz, C6D6, TMS): d = 6.4, 5.5, 2.5 (SiMe3),
~
and ꢀ72.2, ꢀ79.1, ꢀ83 (SiO3); IR (Nujol): m ¼ 1320 (w),
1258 (s), 1245 (s), 1184 (m), 1105 (m), 1075 (w), 1044 (s),
956 (s), 917 (s), 887 (s), 835 (s), 801 (s), 751 (w), 722 (w),
684 (w), 641 (w), 599 (w), 544 (m), 501.41 (w), 484 (m),
419 (m) cmꢀ1
;
Elemental analysis (%) calc. for
[2] (a) F.J. Feher, T.A. Budzichowski, Polyhedron 14 (1995) 3239;
(b) M. Veith, H. Vogelgesang, V. Huch, Organometallics 21 (2002)
380;
C152H272Bi12Cl4N8O36Si16(5886.76): C, 31.01; H, 4.66; N,
1.90. Found: C, 30.78; H, 4.76; N, 2.00%.
(c) K. Merz, S. Block, R. Schoenen, M. Driess, Dalton Trans. (2003)
3365;
4.4. Single-crystal X-ray structure determination of 2 and 3
(d) M.G. Walawalkar, Organometallics 22 (2003) 879.
[3] (a) M.G. Voronkov, E.A. Maletina, V.K. Roman, in: M.E. Vol’pin,
K. Gingold (Eds.), Heterosiloxanes, Soviet Scientific Review supple-
ment, Series Chemistry, vol. 1, Academic Press, London, 1988;
(b) C. Baerlocher, W.M. Meier, D.H. Olson, Atlas of Zeolite
Framework Types, fifth ed., Elsevier, Amsterdam, 2001.
[4] (a) H.N. Stokes, Chem. Ber. 24 (1891) 933;
(b) A. Labenburg, Chem. Ber. 4 (1871) 91.
[5] F. Liebau, Structural Chemistry of Silicates, Springer, Berlin, 1985,
pp. 244–260.
Data for the compound 2 were collected on a Bruker
three-circle diffractometer equipped with a SMART 6000
CCD detector and for the compound 3 were measured on
a STOE-IPDS II diffractometer. Intensity measurements
were performed on a rapidly cooled crystal. The structures
were solved by direct methods (SHELXS-97) [25] and refined
with all data by full-matrix least-squares on F2 [26]. The
hydrogen atoms of C–H bonds were placed in idealized
positions and refined isotropically with a riding model,
whereas the non-hydrogen atoms were refined anisotropi-
cally. In compound 2, the disordered isopropyl groups
and the free THF solvent molecules were refined with dis-
tance and ADP restraints. Crystallographic data (excluding
structure factors) for the structure reported in this paper
have been deposited with the Cambridge Crystallographic
Data Centre: CCDC 281723 for 2 and CCDC 281724 for
3. Copies of the data can be obtained free of charge on
application to CCDC, 12 Union Road, Cambridge CB2
1EZ, UK (fax: (+44)1223 336 033; e-mail: deposit@ccdc.
cam.ac.uk or http://www.ccdc.cam.ac.uk).
´
[6] (a) M.L. Montero, A. Voigt, M. Teichert, I. Uson, H.W. Roesky,
Angew. Chem. 107 (1995) 2761;
(b) Angew. Chem., Int. Ed. Engl. 34 (1995) 2504;
(c) V. Chandrasekhar, R. Murugavel, A. Voigt, H.W. Roesky, H.-G.
Schmidt, M. Noltemeyer, Organometallics 15 (1996) 918;
(d) A. Voigt, R. Murugavel, E. Parisini, H.W. Roesky, Angew.
Chem. 108 (1996) 823;
(e) Angew. Chem., Int. Ed. Engl. 35 (1996) 748;
(f) A. Voigt, M.G. Walawalkar, R. Murugavel, H.W. Roesky, E.
Parisini, P. Lubini, Angew. Chem. 109 (1997) 2313;
(g) Angew. Chem., Int. Ed. Engl. 36 (1997) 2203.
[7] A. Voigt, R. Murugavel, V. Chandrasekhar, N. Winkhofer, H.W.
´
Roesky, H.-G. Schmidt, I. Uson, Organometallics 15 (1996) 1610.
[8] F.R. Hartley, Supported Metal Complexes, Reidel, Boston, MA, 1985.
[9] (a) M. Fujiwara, H. Wessel, H.-S. Park, H.W. Roesky, Tetrahedron
58 (2002) 239;
(b) M. Fujiwara, H. Wessel, H.-S. Park, H.W. Roesky, Chem. Mater.
14 (2002) 4975;
Acknowledgments
(c) H.C.L. Abbenhuis, Chem. Eur. J. 6 (2000) 25.
[10] S.N. Borisov, M.G. Voronkov, E.Y. Lukevits, Organosilicon Het-
eropolymers and Hetero Compounds, Plenum Press, New York,
1970.
We thank the Go¨ttinger Akademie der Wissenschaften
and the Fonds der Chemischen Industrie for support.
[11] (a) A. Voigt, R. Murugavel, H.W. Roesky, Organometallics 15
(1996) 5097;
Appendix A. Supplementary data
(b) U.N. Nehete, G. Anantharaman, V. Chandrasekhar, R. Muru-
gavel, M.G. Walawalkar, H.W. Roesky, D. Vidovic, J. Magull, K.
Samwer, B. Sass, Angew. Chem. 116 (2004) 3920;
(c) Angew. Chem., Int. Ed. 43 (2004) 3832;
(d) G. Anantharaman, N.D. Reddy, H.W. Roesky, J. Magull,
Organometallics 20 (2001) 5777.
Supplementary data associated with this article can be
found, in the online version, at doi:10.1016/j.ica.2005.
12.005.
References
[12] (a) M. Baier, K. Angermaier, H. Schmidbaur, Z. Naturforsch. B 49
(1994) 855;
[1] (a) R. Murugavel, A. Voigt, M.G. Walawalkar, H.W. Roesky, Chem.
Rev. 96 (1996) 2205;
(b) M. Baier, P. Bissinger, J. Blumel, H. Schmidbaur, Chem. Ber. 126
¨
(1993) 947;
(b) R. Murugavel, V. Chandrasekhar, H.W. Roesky, Acc. Chem.
Res. 29 (1996) 183;
(c) F.A. Henglein, R. Lang, K. Scheinost, Makromol. Chem. 18
(1956) 102.
(c) R. Murugavel, M. Bhattacharjee, H.W. Roesky, Appl. Organo-
metal. Chem. 13 (1999) 227;
[13] (a) M.C. Massiani, R. Papiernik, L.G. Hubert-Pfalzgraf, J.C. Daran,
Polyhedron 10 (1991) 437;

U.N. Nehete et al. / Inorganica Chimica Acta 360 (2007) 1248–1257
1257
(b) M. Mehring, M. Schurmann, Chem. Commun. (2001) 2354;
¨
(c) K.H. Whitmire, S. Hoppe, O. Sydora, J.L. Jolas, C.M. Jones,
Inorg. Chem. 39 (2000) 85;
[20] (a) N. Winkhofer, A. Voigt, H. Dorn, H.W. Roesky, A. Steiner, D.
Stalke, A. Reller, Angew. Chem. 106 (1994) 1414;
(b) Angew. Chem., Int. Ed. Engl. 33 (1994) 1352;
(d) D. Mansfeld, M. Mehring, M. Schu¨rmann, Angew. Chem. 117
(2005) 250;
(e) Angew. Chem., Int. Ed. 44 (2005) 245.
(c) R. Murugavel, V. Chandrasekhar, A. Voigt, H.W. Roesky, H.-G.
Schmidt, M. Noltemeyer, Organometallics 14 (1995) 5298.
[21] K. Moedritzer, Inorg. Chem. 3 (1964) 609.
[14] (a) F.J. Feher, T.A. Budzichowski, Organometallics 10 (1991) 812;
(b) F.J. Feher, T.A. Budzichowski, K. Rahimian, J.W. Ziller, J. Am.
Chem. Soc. 114 (1992) 3859.
[22] W. Clegg, N.A. Compton, R.J. Errington, G.A. Fisher, M.E.
Green, D.C.R. Hockless, N.C. Norman, Inorg. Chem. 30 (1991)
4680.
[15] (a) T. Mo¨ller, R. Harjula, A. Paajanen, Sep. Sci. Technol. 38 (2003)
2995;
[23] R. Murugavel, P. Bo¨ttcher, A. Voigt, M.G. Walawalkar, H.W.
Roesky, E. Parisini, M. Teichert, M. Noltemeyer, Chem. Commun.
(1996) 2417.
[24] N.N. Greenwood, A. Earnshaw, Chemistry of the Elements, first ed.,
Pergamon Press, Oxford, 1984.
[25] SHELXS-97, Program for Structure Solution: G.M. Sheldrick, Acta
Crystallogr., Sect. A 46 (1990) 467.
[26] G.M. Sheldrick, SHELXL-97, Program for Crystal Structure Refine-
ment, University of Go¨ttingen, Go¨ttingen, Germany, 1997.
(b) T. Mo¨ller, R. Harjula, M. Pillinger, A. Dyer, J. Newton, E. Tusa,
S. Amin, M. Webb, A. Araya, J. Mater. Chem. 11 (2001) 1526.
[16] P.S. Anand, D.R. Baxi, Ind. J. Technol. 16 (1978) 211.
[17] V. Ghoulipour, S.W. Husain, Anal. Sci. 16 (2000) 1079.
[18] J. Minelly, A. Ellison, Opt. Fiber Technol. 8 (2002) 123.
[19] J.H. Kim, T. Tsurumi, T. Kamiya, M. Daimon, J. Appl. Phys. 75
(1994) 2924.