Multidentate aryloxide and oxo-aryloxide complexes of antimony: Synthesis and structural characterization of [η4-N(o-C6H 4O)3]Sb(OSMe2), {{[η3-N(o-C 6H4OH)(o-C6H4O)2]Sb} 2(μ2-O)}2

Article abstract of DOI:10.1039/b505308k

Antimony compounds that feature multidentate aryloxide ligands, namely [η⁴-N(o-C₆H₄O)₃]Sb(OSMe ₂), {{[η³-N(o-C₆H₄OH)(o-C ₆H₄O)₂]Sb}₂(μ₂-O)} ₂, and {[η³-PhN(o-C₆H₄O) ₂]Sb}₄(μ₃-O)₂ have been synthesized from N(o-C₆H₄OH)₃ and PhN(o-C ₆H₄OH)₂ and structurally characterized by X-ray diffraction. While [η⁴-N(o-C₆H₄O) ₃]Sb(OSMe₂) exists as a discrete mononuclear species, the oxo complexes {{[η³-N(o-C₆H₄OH)(o-C ₆H₄O)₂]Sb}₂(μ₂-O)} ₂ and {[η³-PhN(o-C₆H₄O) ₂]Sb}₄(μ₃-O)₂ are multinuclear. Specifically, the dinuclear fragment {[η³-N(o-C₆H ₄OH)(o-C₆H₄O)₂]Sb} ₂(μ₂-O)} exists in a dimeric form due to the bridging oxo ligand participating in an intermolecular hydrogen bonding interaction, while the dinuclear fragment {[η³-PhN(o-C₆H ₄O)₂]Sb}₂(μ₂-O) exists in a dimeric form due to the bridging oxo ligand serving as a donor to the antimony of a second fragment. The structures of {{[η³-N(o-C ₆H₄OH)(o-C₆H₄O)₂]Sb} ₂(μ₂-O)}₂ and {[η³-PhN(o- C₆H₄O)₂]Sb}₄(μ₃-O) ₂, therefore, indicate that an oxo ligand bridging two Sb ^III centers is sufficiently electron rich to serve as both an effective hydrogen bond acceptor and as a ligand for an additional Sb ^III center. The Royal Society of Chemistry 2005.

Full text of DOI:10.1039/b505308k

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F U L L P A P E R
Multidentate aryloxide and oxo-aryloxide complexes of
antimony: synthesis and structural characterization of
[g4-N(o-C6H4O)3]Sb(OSMe2), {{[g3-N(o-C6H4OH)-
(o-C6H4O)2]Sb}2(l2-O)}2 and {[g3-PhN(o-C6H4O)2]Sb}4(l3-O)2†
Joseph M. Tanski, Bryte V. Kelly and Gerard Parkin*
Department of Chemistry, Columbia University, New York, NY 10027, USA
Received 14th April 2005, Accepted 27th May 2005
First published as an Advance Article on the web 14th June 2005
4
Antimony compounds that feature multidentate aryloxide ligands, namely [g –N(o-C6H4O)3]Sb(OSMe2),
3
3
{{[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2, and {[g -PhN(o-C6H4O)2]Sb}4(l3-O)2 have been synthesized from
4
N(o-C6H4OH)3 and PhN(o-C6H4OH)2 and structurally characterized by X-ray diffraction. While [g -N(o-
3
C6H4O)3]Sb(OSMe2) exists as a discrete mononuclear species, the oxo complexes {{[g -N(o-C6H4OH)(o-
3
C6H4O)2]Sb}2(l2-O)}2 and {[g -PhN(o-C6H4O)2]Sb}4(l3-O)2 are multinuclear. Specifically, the dinuclear fragment
3
{[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)} exists in a dimeric form due to the bridging oxo ligand participating in an
3
intermolecular hydrogen bonding interaction, while the dinuclear fragment {[g -PhN(o-C6H4O)2]Sb}2(l-O) exists in a
dimeric form due to the bridging oxo ligand serving as a donor to the antimony of a second fragment. The structures
3
3
of {{[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2 and {[g -PhN(o-C6H4O)2]Sb}4(l3-O)2, therefore, indicate that an oxo
ligand bridging two SbIII centers is sufficiently electron rich to serve as both an effective hydrogen bond acceptor and
as a ligand for an additional SbIII center.
Introduction
Results and discussion
Antimony compounds are widely used as catalysts for the
synthesis of poly(ethyleneterephthalate), as manufactured un-
As part of an effort to determine the nature of the antimony
catalysts used for the synthesis of poly(ethyleneterephthalate),
we have recently reported the structures of a series of
ethylene glycolate and related catecholate derivatives, namely
[Sb2(OCH2CH2O)3]n, [Sb(OCH2CH2O)(OAc)]n, [pySb(1,2-
O2C6H4)]2O and [pyH][Sb(1,2-O2C6H4)2].7 This investigation
demonstrated that the coordination chemistry of SbIII with
alkoxide ligands is very complex, with a variety of structural
motifs being observed. For example, both [Sb2(OCH2CH2O)3]n
and [Sb(OCH2CH2O)(OAc)]n exhibit extended structures,
as illustrated in Fig. 1. The existence of these extended
ethylene glycolate structures is not surprising given the fact
that simple alkoxides also exhibit polynuclear structures. For
example, [Sb(OMe)3]n exhibits a layer structure with octahedral
R
R
der a variety of brand names, including Dacronꢀ, Mylarꢀ
R
and Teryleneꢀ.1,2 While the most common catalyst for
the synthesis of poly(ethyleneterephthalate) by polyconden-
sation of bis(hydroxyethyl)terephthalate is Sb2O3, other cat-
alysts include alkoxide derivatives, e.g. [Sb2(OCH2CH2O)3]n,3
[Sb(OCH2CH2O)(OAc)]n,4 and Sb(OAr)3.5 Antimony alkoxides,
e.g. Sb(OR)3 (R = Et, Bun), have also been employed as
precursors for the deposition of thin films of Sb2O3 and Sb6O13.6
In this paper, we describe the use of multidentate aryloxide
ligands derived from PhN(o-C6H4OH)2 and N(o-C6H4OH)3 to
prepare a series of antimony aryloxide compounds.
SbIII centers,8 while [Sb(OPri)3]2 and [Sb(OSiMe3)3]2 are
dinuclear with two bridging alkoxide ligands.11 In fact,
9
10
† Dedicated to the memory of Ian P. Rothwell, a true pioneer in the area
of aryloxide chemistry.
Fig. 1 Oligomeric structures of [Sb(OCH2CH2O)(OAc)]n and [Sb2(OCH2CH2O)3]n.
2 4 4 2
D a l t o n T r a n s . , 2 0 0 5 , 2 4 4 2 – 2 4 4 7
T h i s j o u r n a l i s
T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 5
©

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Scheme 1
the first structurally characterized monomeric SbIII aryloxide,
namely Sb(OC6H3-2,6-Me2)3, has only recently been
reported.12,13 Prompted by this observation, we sought to utilize
tetradentate tris(2-hydroxyphenyl)amine (also called 2,2ꢀ,2ꢀꢀ-
nitrilotriphenol), N(o-C6H4OH)3,14 to prepare monomeric an-
timony aryloxide complexes.15
Sb–X distances indicates that while the primary interaction
between the [N(o-C6H4O)3] ligand and antimony is with the
three aryloxide groups (with Sb–O bond lengths in the range
16
˚
2.07–2.11 A), a secondary dative interaction is observed with
17
4
˚
the nitrogen atom [d(Sb–N) = 2.433(2) A]. As such, [g -N(o-
C6H4O)3]Sb(OSMe2) (2) is appropriately classified as possessing
an “atrane” rather than “pro-atrane” structure (Fig. 3).18
Synthesis and structural characterization of
[g4-N(o-C6H4O)3]Sb(OSMe2)
Treatment of Sb(OEt)3 with N(o-C6H4OH)3 in chloroform
results in the precipitation of a white complex with composition
[N(o-C6H4O)3]Sb (1), as illustrated in Scheme 1. Although
the reaction does not yield single crystals suitable for X-
4
ray diffraction, appropriate crystals of composition [g -N(o-
C6H4O)3]Sb(OSMe2) (2) may be obtained by crystallization from
Fig. 3 Atrane and pro-atrane structures.
warm dimethylsulfoxide solution. The molecular structure of
[g -N(o-C6H4O)3]Sb(OSMe2) (2) has been determined by X-
ray diffraction, as illustrated in Fig. 2. Comparison of the
4
[N(o-C6H4O)3] has not been widely studied as a ligand with
respect to main group metal chemistry, although aluminium,19
germanium,20 and tin21 derivatives have been reported. With
respect to group 15 elements, however, only the phosphorus com-
3
3
plexes [g -N(o-C6H4O)3]P and [g -N(o-C6H4O)3]PO have been
reported, and these possess “pro-atrane” structures that are de-
4
void of N–P interactions.22 Thus, [g -N(o-C6H4O)3]Sb(OSMe2)
(2) is the first example of a structurally characterized atrane
[N(o-C6H4O)3]-complex of the group 15 elements. The obser-
4
vation that [g -N(o-C6H4O)3]Sb(OSMe2) possesses an atrane
geometry, while the phosphorus counterpart does not, is un-
doubtedly linked to the fact that antimony is larger and more
metallic in nature than phosphorus.
4
As
a
consequence of the atrane nature of [g -N(o-
C6H4O)3]Sb(OSMe2) (2), the antimony is five-coordinate and
the geometry is based on a square pyramid; the lone pair is,
therefore, stereochemically active and occupies the coordination
site trans to the axial nitrogen donor.23 It is also noteworthy that
the antimony is displaced from the square plane such that the
N–Sb–O angles are less than 90◦ (69.7–86.1◦). Displacement of
this type is precedented for isoelectronic species. For example,
the Fax–I–Feq bond angle in IF5 is 81.9◦.24
4
Fig. 2 Molecular structure of [g -N(o-C6H4O)3]Sb(OSMe2) (2). Se-
˚
lected bond lengths (A): Sb–O1 2.072(2), Sb–O2 2.114(2), Sb–O3
2.066(2), Sb–O1S 2.305(2), Sb–N 2.433(2). Selected bond angles
(◦): O1–Sb–O2 94.5(1), O2–Sb–O1S 79.3(1), O1S–Sb–O3 80.65(9),
O3–Sb–O1 92.8(1), O1–Sb–N 74.26(9), O2–Sb–N 69.67(9), O3–Sb–N
74.16(9), O1S–Sb–N 86.08(9), C11–N–C21 111.6(2), C21–N–C31
118.6(2), C11–N–C31 110.3(2) (the structure illustrated is inverted from
that corresponding to the atomic coordinates provided in the CIF file).
The Me2SO ligand can be viewed as modeling the co-
ordination of bis(hydroxyethyl)terephthalate to antimony in
the polyesterifcation catalytic cycle and, in this regard, it is
pertinent to note that the Sb–OSMe2 bond length [2.305(2)
˚
A] is notably longer than the three Sb-aryloxide bond lengths
D a l t o n T r a n s . , 2 0 0 5 , 2 4 4 2 – 2 4 4 7
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4
˚
[2.07–2.11 A]. With respect to the geometry at nitrogen in [g -
N(o-C6H4O)3]Sb(OSMe2) (2), the three C–N–C bond angles
[118.6(2)◦, 110.3(2)◦, and 111.6(2)◦] sum to 340.5◦ indicating
that it is significantly more pyramidal than that in the free ligand,
N(o-C6H4OH)3, with RC–N–C = 348.3◦.25
Synthesis and structural characterization of the oxo complex
{{[g3-N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2
In addition to the role of antimony(III) alkoxides and aryloxides
as polycondensation catalysts, these species are also of interest
with respect to their use in the preparation of thin films of
antimony oxides via chemical vapor deposition.6 Furthermore,
antimony alkoxides may also be used to prepare oxide materials
via the sol–gel process,26 including the synthesis of mixed metal
oxides.27 For example Sb(OR)3 and Sn(ORꢀ)4 have been used
to prepare antimony-doped tin oxide,28 a material that has
been widely studied because of its semiconductor properties
and its application as a gas sensor.29–31 Oxo-alkoxides are
key intermediates of the sol–gel process32 and it is therefore
noteworthy that we have isolated a discrete oxo complex via
controlled hydrolysis of {[N(o-C6H4O)3]Sb}n. Thus, addition of
H2O to {[N(o-C6H4O)3]Sb}n, generated in situ via treatment of
Sb(OEt)3 with N(o-C6H4OH)3, yields the oxo bridged complex
3
Fig. 5 Extended structure of {{[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-
ꢀ
˚
O)}2. Selected distances (A): O13 · · · O2S 2.742(4), O1–O23 2.634(3),
Sb2–O1S 2.804(4). The atoms marked with a prime (ꢀ) are related to the
corresponding unprimed atoms via an inversion center located at the
centroid of the Sb–O1S–Sbꢀ–O1Sꢀ rectangle.
˚
a longer O · · · O distance of 2.74 A, thereby indicating that the
oxo ligand is a better hydrogen bond acceptor than a THF
molecule in this system. Finally, the Sb–N distance increases
from the value of 2.43 A in [g -N(o-C6H4O)3]Sb(OSMe2) (2) to
4
˚
3
˚
˚
2.60 A and 2.62 A in {{[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-
O)}2 (3). The increase in Sb–N bond length is also accompanied
by a reduction in the pyramidal nature of the nitrogen atom, as
illustrated by comparison of the sum of the C–N–C◦bond angles
3
{{[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2 (3), in which the
generation of the oxo bridge is accompanied by the formation
3
of a phenolic group. The molecular structure of {{[g -N(o-
C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2 (3) has been determined by
X-ray diffraction (Figs. 4 and 5), thereby demonstrating the
multinuclear nature of the oxo complex. There are several
4
3
for [g -N(o-C6H4O)3]Sb(OSMe2) (2) (RC–N–C = 340.5 ) and {{[g -
N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2 (3) (RC–N–C = 344.8◦ and
345.3).
3
noteworthy features pertaining to the structure of {{[g -N(o-
Although antimony(III) oxide compounds are precedented,
the majority of these are organoantimony derivatives,35,36 as
illustrated by (R2Sb)2O.37 An interesting feature of the structures
of (R2Sb)2O pertains to the conformational preferences of the
two R2Sb fragments, of which the two extreme syn–syn and syn–
anti conformations are illustrated in Fig. 6.37–40 While the direct
C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2 (3). Firstly, while the pri-
mary coordination geometries of the two antimony centers
are similar, comprising one oxide, one amine, and two ary-
3
loxide interactions, the two centers of the discrete {[g -N(o-
C6H4OH)(o-C6H4O)2]Sb}2(l2-O)} unit differ by virtue of the
fact that an aryloxide group attached to one of the antimony
centers interacts weakly with the other antimony, with an
3
comparison with {{[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2
(3) is complicated by the fact that the antimony exhibits a higher
coordination number due to interaction with the nitrogen and
the bridging aryloxide group, it is evident that the dinuclear unit
Sb · · · O distance of 2.91 A,33 while the other antimony interacts
˚
˚
with a THF molecule, with an Sb · · · O distance of 2.80 A
(Figs. 4 and 5). Secondly, the bridging oxo ligand participates
in an intermolecular hydrogen bonding interaction with the
3
{[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)} is best described as
having a syn–anti conformation with respect to the Sb–OAr
OH group of another molecule, with an O · · · O distance of
interactions (Fig. 7).
34
˚
2.63 A, thereby resulting in the formation of a tetranuclear
species (Fig. 5). For comparison, the other OH group is involved
in a hydrogen bonding interaction with a THF molecule, with
Fig. 6 Conformations of bridging oxo complexes indicating the
presumed location of the lone pairs on antimony.
Fig. 7 Syn–anti conformations with respect to the Sb–OAr interactions
3
for the dinuclear moiety in{{[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2
3
and {[g -PhN(o-C6H4O)2]Sb}4(l3–O)2.
3
Fig.
4
Dinuclear portion of the molecular structure of {{[g -
Synthesis and structural characterization of the oxo complex
˚
N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2. Selected bond lengths (A):
Sb1–O11 2.015(2), Sb1-O12 1.980(2), Sb1–O1 1.992(2), Sb1–N1
2.601(2), Sb1–O22 2.912(2), Sb2–O21 2.013(2), Sb2–O22 2.011(2), Sb2–
O1 1.976(2), Sb2–N2 2.619(2). Selected bond angles (◦): C16–N1–C118
116.7(2), C112–N1–C118 116.7(3), C16–N1–C112 111.4(2), C212–N2–
C218 117.9(2), C26–N2–C218 115.9(2), C26–N2–C212 111.5(2).
{[g3-PhN(o-C6H4O)2]Sb}4(l3-O)2
In view of the existence of a hydrogen bonding interac-
3
tion to the bridging oxo ligand within {{[g -N(o-C6H4OH)(o-
C6H4O)2]Sb}2(l2-O)}2 (3), it was of interest to ascertain how
2 4 4 4
D a l t o n T r a n s . , 2 0 0 5 , 2 4 4 2 – 2 4 4 7

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the nature of the complex would be modified in the absence
of a hydrogen bond donor. For this purpose, the analogue
in which the phenolic-OH group is formally replaced by H,
3
i.e. {[g -PhN(o-C6H4O)2]Sb}4(l3-O)2 (4), was synthesized by
treatment of Sb(OEt)3 with PhN(o-C6H4OH)2 followed by
3
addition of H2O (Scheme 2).41 The molecular structure of {[g -
PhN(o-C6H4O)2]Sb}4(l3-O)2 (4) has been determined by X-
ray diffraction (Figs. 8 and 9). Comparison of Figs. 4 and 8
indicates that the basic dinuclear [PhN(o-C6H4O)2Sb]2(O) unit
3
is similar to that of {[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}.
Furthermore, the dinuclear moiety [PhN(o-C6H4O)2Sb]2(O) also
exhibits a syn–anti conformation with respect to the Sb–OAr
3
Fig. 9 Molecular structure of {[g -PhN(o-C6H4O)2]Sb}4(l3-O)2. Se-
ꢀ
˚
lected bond lengths (A): Sb1–O1 2.446(6), Sb2–O1 1.989(6), Sb1–O1
1.992(5).
interactions (Fig. 7). Despite these similarities, a significant
3
difference in the structures of {[g -PhN(o-C6H4O)2]Sb}4(l3-O)2
3
(4) and {[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)} results from
the fact that there is no hydrogen bond donor in the former
molecule to provide a stabilizing interaction with the bridging
oxo ligand. As a consequence, the oxo ligand interacts with
a third antimony, thereby resulting in a discrete tetranuclear
˚
˚
complex, with Sb–O bond lengths of 1.992(5) A, 1.989(6) A,
˚
and 2.446(6) A (Fig. 9). Trigonal planar l3-oxo ligands are
not common in antimony chemistry but a related motif is
observed within the infinite chain of [(Me2Sb)2O]n, for which
˚
the bridging oxo ligand exhibits two short [1.99 and 2.10 A]
˚
and one long bond [2.59 A] to three antimony atoms; a
similar l3-oxo ligand environment is also observed in valentinite,
an orthorhombic modification of Sb2O3.39 Another interesting
example of an antimony complex with a trigonal planar l3-oxo
+
ligand is provided by {[Me2Sb]3(l3-O)} , for which the three
42
˚
Sb–O distances are identical, 2.116(1) A.
Finally, with respect to the coordination of the [PhN(o-
˚
˚
C6H4O)2] ligand, the Sb–N distances [2.68 A and 2.72 A] are
Scheme 2
3
longer than those of {{[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-
˚
˚
O)}2 (3) [2.60 A and 2.62 A], and the nitrogen atoms are less
pyramidal, with RC–N–C = 345.6◦ and 352.6◦. On the basis of
these observations, it is evident that by comparison to [N(o-
C6H4O)3], the nitrogen atom of the [PhN(o-C6H4O)2] ligand
shows a reduced tendency to serve as a donor.
Summary
In conclusion, a series of antimony compounds that fea-
ture multidentate aryloxide ligands has been synthesized us-
4
ing N(o-C6H4OH)3 and PhN(o-C6H4OH)2. While [g -N(o-
C6H4O)3]Sb(OSMe2) (2) exists as a discrete mononuclear species,
treatment with water results in a dinuclear bridging oxo complex
3
{{[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2 (3) in which the
oxo ligand participates in a hydrogen bonding interaction with
an OH group. In the absence of a hydrogen bond donor,
the bridging oxo ligand interacts with an additional antimony
3
center, such that {[g -PhN(o-C6H4O)2]Sb}4(l3-O)2 (4), exists as a
3
3
Fig. 8 Molecular structure of the dinuclear portion of {[g -PhN(o-
tetranuclear complex. The structures of {{[g -N(o-C6H4OH)(o-
˚
3
C6H4O)2]Sb}4(l3–O)2. Selected bond lengths (A): Sb1-O11 2.001(6),
C6H4O)2]Sb}2(l2-O)}2 (3) and {[g -PhN(o-C6H4O)2]Sb}4(l3-O)2
Sb1–O12 2.121(6), Sb1–O1 1.992(5), Sb1–N1 2.723(7), Sb2–O21
2.005(7), Sb2–O22 1.986(7), Sb2–O1 1.989(6), Sb2–O12 2.538(6),
Sb2–N2 2.684(8). Selected bond angles (◦): C112–N1–C113 115.8(7),
C112–N1–C16 112.6(7), C113–N1–C16 117.2(7), C212–N2–C213
117.7(9), C212–N2–C26 115.2(9), C213–N2–C26 119.7(9).
(4), therefore, indicate that an oxo ligand bridging two SbIII
centers is sufficiently electron rich that it serves as both an
effective hydrogen bond acceptor and as a ligand for an
additional SbIII center.
D a l t o n T r a n s . , 2 0 0 5 , 2 4 4 2 – 2 4 4 7
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was added and the mixture was stirred for 3 days. After this
period, the mixture was concentrated to ca. 25 mL and cooled
to 0 ◦C with an ice-water bath. The mixture was filtered and
the precipitate was washed with CHCl3 (5 mL) and dried in
Experimental
General considerations
All manipulations were performed using a combination of
glovebox, high-vacuum and Schlenk techniques under a nitrogen
or argon atmosphere, except where stated otherwise. Solvents
were purified and degassed by standard procedures. NMR
spectra were measured on Bruker 300wb DRX, Bruker Avance
400 DRX, and Bruker Avance 500 DMX spectrometers. IR
spectra were recorded as Nujol mulls on KBr plates on a Perkin-
Elmer Paragon 1000 spectrometer. N(o-C6H4OH)314 and PhN(o-
3
vacuo giving {{[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2 (3) as
a white solid (0.254 g, 71%). Anal. Calcd. for C36H26N2O7Sb2:
C, 51.3%; H, 3.1%; N, 3.3%. Found: C, 51.2%; H, 2.5%; N,
3.1%. IR Data (Nujol, cm−1): 1924 (w), 1792 (w), 1590 (s), 1213
(m), 1194 (s), 1161 (m), 1148 (m), 1144 (m), 1114 (m), 1102 (s),
1040 (m), 1030 (s), 963 (w), 946 (w), 931 (m), 920 (m), 908 (m),
860 (s), 831 (s), 767 (s), 758 (s), 728 (m), 703 (m), 654 (m), 641
(s), 634 (s), 622 (s), 611 (s), 598 (s), 587 (s), 572 (m), 550 (m),
25
C6H4OH)2 were prepared by the literature methods. Sb(OEt)3
3
534 (w), 517 (m), 504 (s), 476 (m), 457 (m), 447 (w). {{[g -N(o-
was obtained from Strem. Elemental analyses were performed
by Robertson Microlit Laboratories Inc., Madison, NJ 07940.
C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2 (3) is insufficiently soluble
1
for H NMR spectroscopic analysis, but a sample degraded in
Synthesis of [g4-N(o-C6H4O)3]Sb(OSMe2) (2)
CD3OD with 2 drops DCl (20% in D2O) revealed the presence
of N(o-C6H4OD)3 and the absence of ethanol. Crystals suitable
for X-ray diffraction were obtained from THF.
A mixture of Sb(OEt)3 (0.876 g, 3.4 mmol) and N(o-C6H4OH)3
(1.000 g, 3.4 mmol) was dissolved in CH2Cl2 (ca. 25 mL). The
mixture was stirred and a white precipitate started to form after
about 30 s of stirring. The mixture was concentrated to ca. 10 mL
and then stirred for 18 h at room temperature. The mixture was
filtered and the precipitate was washed with CH2Cl2 (2 × 10 mL)
and dried in vacuo giving [N(o-C6H4O)3]Sb (1) as a white solid
(0.370 g, 26%). Anal. Calcd. for C18H12NO3Sb: C, 52.5%; H,
2.9%; N, 3.4%. Found: C, 52.3%; H, 2.8%; N, 3.2%. IR Data
(Nujol, cm−1): 1926 (w), 1794 (w), 1590 (s), 1211 (m), 1194 (m),
1161 (w), 1146 (m), 1113 (m), 1102 (s), 1040 (m), 1030 (s), 964
(w), 945 (w), 931 (m), 918 (m), 908 (m), 894 (w), 858 (s), 832
(s), 767 (s), 755 (s), 746 (s), 703 (m), 654 (m), 640 (m), 633
(s), 622 (s), 611 (s), 598 (s), 587 (s), 571 (m), 550 (m), 533 (w),
517 (m), 504 (s), 477 (m), 456 (m), 447 (w). [N(o-C6H4O)3]Sb
(1) is insufficiently soluble for 1H NMR spectroscopic analysis,
but a sample degraded in CD3OD with 2 drops DCl (20% in
D2O) revealed the presence of N(o-C6H4OD)3 and the absence
Synthesis of {[g3-PhN(o-C6H4O)2]Sb}4(l3-O)2 (4)
Sb(OEt)3 (0.185 g, 0.72 mmol) was added to a solution of PhN(o-
C6H4OH)2 (0.200 g, 0.72 mmol) in THF (ca. 15 mL) and the
mixture was stirred at room temperature for 18 h. H2O (3 lL,
0.17 mmol) was added and the mixture was stirred for a further
24 h. After this period, the mixture was concentrated to ca. 3 mL,
thereby resulting in the slow formation of a white precipitate.
The mixture was filtered and the precipitate was dried in vacuo
3
giving {[g -PhN(o-C6H4O)2]Sb}4(l3-O)2·2THF as a white solid
(0.275 g, 80%). Anal. Calcd. for C36H26N2O5Sb2·THF: C, 54.5%;
H, 3.9%; N, 3.2%. Found: C, 56.0%; H, 3.7%; N, 3.0%. IR Data
(Nujol, cm−1): 1590 (s), 1228(s), 1154 (w), 1105 (m), 1062 (m),
1034 (m), 914 (m), 856 (m), 839 (m), 824 (m), 778 (m), 752
(s), 704 (w), 696 (m), 644 (m), 604 (s), 530 (m), 504 (m), 496
3
(m), 484 (s), 472 (m), 450 (w). [g -PhN(o-C6H4O)2Sb]4(l3-O)2 is
insufficiently soluble for 1H NMR spectroscopic analysis, but a
sample degraded in CD3OD with 2 drops DCl (20% in D2O)
revealed the presence of PhN(o-C6H4OH)2 and THF in a 2 : 1
ratio, and the absence of ethanol. Crystals suitable for X-ray
diffraction were obtained from THF.
4
of ethanol. Crystals of [g -N(o-C6H4O)3]Sb(OSMe2) (2) suitable
for X-ray diffraction were obtained by slow cooling of a warm
solution of [N(o-C6H4O)3]Sb (1) in Me2SO.
Synthesis of {{[g3-N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2 (3)
X-Ray structure determinations
A mixture of Sb(OEt)3 (0.219 g, 0.85 mmol) and N(o-C6H4OH)3
(0.250 g, 0.85 mmol) was dissolved in CHCl3 (ca. 50 mL). The
mixture was stirred and a white precipitate started to form
after about 30 s of stirring. The mixture was stirred at room
temperature for 18 h, after which period H2O (10 lL, 0.56 mmol)
X-Ray diffraction data were collected on a Bruker P4 diffrac-
tometer equipped with a SMART CCD detector; crystal data,
data collection and refinement parameters are summarized in
Table 1. The structures were solved using direct methods and
Table 1 Crystal, intensity collection and refinement data.
3
3
{{[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2-
{[g -PhN(o-C6H4O)2]Sb}4-
(l3-O)2·2THF
[N(o-C6H4O)3]Sb(OSMe2)
(l2-O)}2·2.18THF
Lattice
Formula
Formula weight
Triclinic
Triclinic
Triclinic
C20H18NO4Sb
490.16
C36H26N2O7Sb2·2.18(C4H8O)
C80H68N4O12Sb4
882.19
999.27
¯
¯
¯
Space group
P1
P1
P1
˚
a/A
8.452(1)
8.734(1)
13.960(2)
96.289(2)
90.953(2)
112.482(2)
944.4(2)
2
13.1256(7)
13.3738(8)
14.4188(8)
111.544(1)
99.969(1)
108.335(1)
2111.9(2)
2
9.763(1)
10.852(2)
17.345(3)
85.217(3)
76.467(3)
88.987(3)
1780.5(5)
1
˚
b/A
˚
c/A
a/◦
b/◦
c /◦
V/A
Z
3
˚
Temperature/K
243
0.71073
1.724
1.597
28.0
243
0.71073
1.571
1.337
28.3
243
0.71073
1.646
1.568
28.3
˚
Radiation k/A
q (calcd.)/g cm−3
l (M◦o-Ka)/mm−1
hmax
/
No. of data
No. of parameters
4058
247
9236
532
7863
452
R1
wR2
GOF
0.0395
0.1083
1.032
0.0335
0.0880
1.007
0.0681
0.1785
1.039
2 4 4 6
D a l t o n T r a n s . , 2 0 0 5 , 2 4 4 2 – 2 4 4 7

View Article Online
standard difference map techniques, and were refined by full-
22 E. Mu¨ller and H. B. Bu¨rgi, Helv. Chim. Acta, 1987, 70, 1063–
1069.
matrix least-squares procedures on F2 with SHELXTL (Version
23 For other examples of square pyramidal SbIII compounds, see:
(a) L. Golic and S. Milicev, Acta Crystallogr., 1978, B34, 3379–3381;
(b) I. A. Razak, H.-K. Fun, B. M. Yamin, K. Chinnakali, H. Zakaria
and N. B. Ismail, Acta Crystallogr., 1999, C55, 172–174; (c) H. L.
Byers, K. B. Dillon and A. E. Goeta, Inorg. Chim. Acta, 2003, 344,
239–242.
3
5.10).43 Crystals of {{[g -N(o-C6H4OH)(o-C6H4O)2]Sb}2(l2-
O)}2 (3) were obtained from THF, and three crystallographically
independent THF molecules are present in the asymmetric unit.
Of these, one molecule is weakly coordinated to antimony, one
is involved in hydrogen bonding to the o-C6H4OH group, and a
third is not involved in any specific interaction and exhibits only
partial occupancy (0.18).
24 R. D. Burbank and G. R. Jones, Inorg. Chem., 1974, 13, 1071–1074.
25 B. V. Kelly, J. M. Tanski, M. B. Anzovino and G. Parkin, J. Chem.
Crystallogr., in press.
26 For reviews on sol-gel processes involving alkoxides, see: (a) U.
Schubert, N. Hu¨sing and A. Lorenz, Chem. Mater., 1995, 7, 2010–
2027; (b) D. C. Bradley, Chem. Rev., 1989, 89, 1317–1322.
27 (a) R. C. Mehrotra, A. Singh, M. Bhagat and J. Godhwani, J. Sol-
Gel Sci. Technol., 1998, 13, 45–49; (b) L. G. Hubert-Pfalzgraf, Inorg.
Chem. Commun., 2003, 6, 102–120; (c) L. G. Hubert-Pfalzgraf,
J. Mater. Chem., 2004, 14, 3113–3123.
CCDC reference numbers 268879–268881.
See http://www.rsc.org/suppdata/dt/b5/b505308k/ for cry-
stallographic data in CIF or other electronic format.
Acknowledgements
We thank the National Science Foundation (CHE-03-50498) for
support of this research.
28 (a) M. Guglielmi, E. Menegazzo, M. Paolizzi, G. Gasparro, D. Ganz,
J. Pu¨tz, M. A. Aegerter, L. Hubert-Pfalzgraf, C. Pascual, A. Dura´n,
H. X. Willems, M. Van Bommel, L. Bu¨ttgenbach and L. Costa, J. Sol-
Gel Sci. Technol., 1998, 13, 679–683; (b) R. Puyane´ and I. Kato, Proc.
SPIE, Int. Soc. Opt. Eng., 1983, 401, 190–197.
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˚
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University of Gottingen, Gottingen, Federal Republic of Germany,
1981.
¨
¨
D a l t o n T r a n s . , 2 0 0 5 , 2 4 4 2 – 2 4 4 7
2 4 4 7