Triorganoantimony(V) carboxylates: Synthesis, characterization and crystal structure of [Me3Sb(O2C-C5H4N)2] · H2O

Article abstract of DOI:10.1016/j.jorganchem.2007.07.033

Reactions of [R₃Sb(OPrⁱ)₂] with N-heterocylic carboxylic acids gave compounds of the type [R₃Sb(O₂C-Ar)₂] (1) (R = Me, Et, Prⁱ, Ph; Ar = 2-C₅H₄N, 2-C_9<

Full text of DOI:10.1016/j.jorganchem.2007.07.033

Journal of Organometallic Chemistry 692 (2007) 4928–4932
www.elsevier.com/locate/jorganchem
Triorganoantimony(V) carboxylates: Synthesis, characterization
and crystal structure of [Me3Sb(O2C–C5H4N)2] Æ H2O
a
a,
a
b,
*
Kamal R. Chaudhari , Vimal K. Jain *, V.S. Sagoria , Edward R.T. Tiekink
a
Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
Department of Chemistry, The University of Texas at San Antonio, One UTSA Circle, TX 78249-0698, USA
b
Received 11 June 2007; received in revised form 2 July 2007; accepted 3 July 2007
Available online 31 July 2007
Abstract
Reactions of [R3Sb(OPri)2] with N-heterocylic carboxylic acids gave compounds of the type [R3Sb(O2C–Ar)2] (1) (R = Me, Et, Pri,
Ph; Ar = 2-C5H4N, 2-C9H6N). The mono-bromo compound [Me3Sb(Br)(O2C–C5H4N)] (2) exists in equilibrium with [Me3Sb(O2C–
C5H4N)2] and [Me3SbBr2]. All new compounds have been characterized by IR and NMR (1H and 13C{1H}) spectral data. X-ray struc-
tural analysis of one example, [Me3Sb(O2C–C5H4N)2], isolated as its monohydrate, revealed an essentially trigonal bipyramidal geometry
for the antimony atom defined by three equilaterally disposed methyl groups and two oxygen atoms from monodentate carboxylate
groups, in apical positions. The crystal structure is consolidated into a three-dimensional network by cooperative O–Hꢀ ꢀ ꢀO,
O–Hꢀ ꢀ ꢀN and C–Hꢀ ꢀ ꢀO interactions.
ꢀ 2007 Elsevier B.V. All rights reserved.
Keywords: Triorganoantimony; Picolinic acid; Quinaldic acid; NMR; X-ray structure
1. Introduction
moieties, a series of compounds have been synthesized
and one of them, namely [Me3Sb(O2C–C5H4N)2], has been
fully characterized by single-crystal X-ray crystallography
as its monohydrate. Results of this work are described
herein.
Organoantimony(V) complexes containing an Sb–O–R
linkage (where OR = alkoxy, phenoxy, carboxylate, oxi-
mate) have been investigated in considerable detail [1–5].
Their mono- and di-organoantimony(V) complexes are
quite often dimeric [1,6] whereas tri- and tetra-organoanti-
mony derivatives are monomeric, with the central metal
atom acquiring a trigonal bipyramidal configuration. Anio-
nic bidentate ligands, such as acetylacetonateꢁ, oxinateꢁ (8-
hydroxyquinolate ion), Schiff bases, etc., in general, yield
hexa-coordinated tri- and tetra-organoantimony complexes
[1,7,8].
2. Results and discussion
2.1. Synthesis and spectroscopic characterization
Reactions of [R3Sb(OPri)2] with two equivalents of
N-heterocyclic carboxylic acids in benzene afforded colour-
less bis(carboxylates), [R3Sb(O2C–Ar)2] (R = Me, Et, Pri,
Ph; Ar = C5H4N, C9H6N) in nearly quantitative yields as
per Eq. (1). The IR spectra displayed absorptions in the
region 1678–1630 cmꢁ1 attributable to m(C@O) indicating
the presence of a free carbonyl group. The m(Sb–C) absorp-
tions in trialkylantimony(V) compounds have been
assigned in the region 495–565 cmꢁ1 [12]. The 1H and
13C{1H} NMR spectra displayed characteristic peaks
assignable to R3Sb(V) and the carboxylate fragments.
2-Picolinic acid and related carboxylic acids have been
used to stabilize higher coordination either through O\N
chelation or via carboxylate bridges [9–11]. To assess their
coordination behaviour towards triorganoantimony(V)
*
Corresponding authors.
E-mail addresses: jainvk@barc.gov.in (V.K. Jain), edward.tiekink@
utsa.edu (E.R.T. Tiekink).
0022-328X/$ - see front matter ꢀ 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2007.07.033

K.R. Chaudhari et al. / Journal of Organometallic Chemistry 692 (2007) 4928–4932
4929
The resonances of the R3Sb(V) fragment due to the a-car-
bon and the protons attached to this carbon are consider-
ably shielded from the corresponding signals for the
corresponding dibromide (R3SbBr2) in the 13C{1H} and
1H NMR spectra, respectively. This shielding can be
ascribed to the coordination of more electronegative oxy-
gen, compared with bromide, to the antimony atom. Nitro-
gen coordination of heterocyclic aprotic ligands to metal
atoms is manifested in the form of deshielding of the C-4
carbon resonance by ꢂ3 ppm [7,9,10,13]. In the present
case, the C-4 resonance of 2-picolinate is little affected on
coordination of the carboxylate ligands from its position
for the free ligand suggesting an absence of Sb–N coordina-
tion, which was confirmed by X-ray crystal structure of 1a
(see below).
½R3SbðOPriÞ ꢃ þ 2ArCO2H ! ½R3SbðO2C–ArÞ ꢃ þ 2PriOH
2
2
ðR ¼ Me;Et;Pri;Ph;Ar ¼ 2-C5H4N;2-C9H6NÞ
ð1Þ
Attempts to prepare [Me3Sb(Br)(O2C–C5H4N)] by the
reaction of Me3SbBr2 with one equivalent of NaO2C–
C5H4N lead to the formation of a mixture containing
Me3SbBr2, [Me3Sb(Br)(O2C–C5H4N)], (2) and (1a), as re-
vealed by NMR spectroscopy. A similar equilibrium was
established when CDCl3 solutions of 1a and [Me3SbBr2]
were mixed in 1:1 stoichiometry at room temperature as
per Eq. (2). The relative ratio did not change even after
Fig. 1. Molecular structure and crystallographic labelling scheme for the
crystallographic asymmetric unit of [Me3Sb(O2C–C5H4N)2] Æ H2O. The
hydrogen-bonds formed between the water molecule and [Me3Sb(O2C–
C5H4N)2] are shown as black-dashed lines. Selected geometric parameters:
Sb–O1 2.135(4), Sb–O3 2.154(4), Sb–C13 2.093(5), Sb–C14 2.091(6), Sb–
C15 2.117(6), O1–C6 1.300(7), O2–C6 1.231(7), O3–C12 1.295(7), O4–C12
1
refluxing the solution for 3 h. The H NMR spectrum in
C6D6 also showed the presence of these three species; only
the chemical shifts showed the expected solvent effect.
However, 1H NMR spectra recorded in DMSO-d6 and
CD3OD displayed a broad signal for Me3Sb(V) protons,
suggesting the exchange process faster on NMR time scale
in these solvents.
˚
1.230(7) A; O1–Sb–O3 171.91(15)ꢁ.
ate ligands; the axial O1–Sb–O3 is 171.91(15)ꢁ. The coordi-
nation geometry is based on a trigonal bipyramid but there
are significant distortions from the ideal geometry. As can
be seen from Fig. 1, the carboxylate ligands adopt different
orientations with respect to the central antimony atom.
The O3,O4-carboxylate adopts the conventional orienta-
tion in which the O4 atom is directed towards the antimony
½Me3SbðO2C–C5H4NÞ2ꢃ þ Me3SbBr2 ꢀ2½Me3SbðBrÞðO2C–C5H4NÞꢃ
ð2Þ
Anionic bidentate ligands, such as acetylacetonateꢁ, oxi-
nateꢁ, readily form six-coordinated [R3SbX(L)] (X = Cl
or Br; L = acetylacetonate, oxinate) containing chelating
ligands. These complexes are stable both in solution and
in the solid-state. Surprisingly, compound 2 exists in
equilibrium with 1a and Me3SbBr2 in solution, although
2-picolinate ion is known to give five-membered O\N che-
lated metal complexes similar to oxinate [1,10].
˚
atom, being separated by 3.024(4) A. The O1,O2-carboxyl-
ate ligand adopts a different orientation so as to place the
pyridine-N1 in close proximity to the antimony atom; the
˚
Sbꢀ ꢀ ꢀN1 distance is 2.665(5) A. While neither distance is
indicative of a significant bonding interaction to the anti-
mony atom, the close approach of these atoms is responsi-
ble for the widening of the trigonal C13–Sb–C14 angle to
146.3(2)ꢁ compared with the narrower C13–Sb–C15 and
C14–Sb–C15 angles of 105.5(2)ꢁ and 107.8(2)ꢁ, respec-
tively. Each of the two 2-picolinate ligands is approxi-
mately planar as manifested in the O1–C6–C1–N1 and
O3–C12–C7–N2 torsion angles of 6.8(7)ꢁ and ꢁ17.8(8)ꢁ,
respectively. Further, the dihedral angle between the pyri-
dine rings is only 23.5(3)ꢁ, indicating that the molecule
almost achieves mirror symmetry. As mentioned above,
the water molecule is associated with the [Me3Sb(O2C–
C5H4N)2] molecule and from Fig. 1 it is clear that it strad-
dles the O3 and N2 atoms. The water molecule is somewhat
2.2. Crystallographic structure of [Me3Sb(O2C–C5H4N)2]
Æ H2O
The molecular structure of [Me3Sb(O2C–C5H4N)2],
characterised as its monohydrate, is illustrated in Fig. 1
which shows the hydrogen-bonds formed between the com-
ponents of the crystallographic asymmetric unit; selected
geometric parameters are listed in the caption to the figure.
The antimony atom exists within a trans-C3O2 donor set
defined by three methyl-carbon atoms and two oxygen
atoms, derived from two essentially monodentate carboxyl-

4930
K.R. Chaudhari et al. / Journal of Organometallic Chemistry 692 (2007) 4928–4932
removed from the O3–C12–C7–N2 plane and forms rather
long O–Hꢀ ꢀ ꢀO, N separations [14]. It is easy to envisage the
water molecule moving in closer to the basic atoms. How-
ever, its relative position in the crystal structure allows for
the relatively close approach of adjacent molecules and
hence, the formation of C–Hꢀ ꢀ ꢀO contacts. Indeed, the
water-O5 atom accepts two such contacts [14] from two
symmetry related molecules and thereby plays a pivotal
role in the stabilisation of the crystal structure. Additional
C–Hꢀ ꢀ ꢀO contacts involve the carboxylate-O2 and -O4
atoms [14]. A view of the crystal packing diagram is shown
in Fig. 2 which illustrates the cohesiveness of the crystal
structure owing to the presence of the various intermolecu-
lar interactions, detailed above, that extend in three-
dimensions.
son is that of [Me3Sb(O2CCH2–C5H4N-2)], i.e. with a
–CH2– bridge between the carboxylato and pyridine resi-
dues [17]. Here, not surprisingly, both oxygen atoms of
each carboxylato residue of each of the two crystallograph-
ically independent molecules are oriented towards the anti-
mony atom as the positions of the nitrogen atoms preclude
intramolecular association to the central atom [17]. In
this structure, the range of Sb–Oshort distances is
˚
2.119(3)–2.133(3) A, and Sb–Olong distance range is
˚
3.012(6)–3.112(4) A, i.e. akin to those seen in the structure
of [Me3Sb(O2C–C5H4N)2] Æ H2O. Of the triarylantimony
dicarboxylates, the most relevant structure of comparison
is that of [Ph3Sb(O2C–C5H4N)2] [17]. Here, the presence
of the somewhat electronegative phenyl groups increases
the Lewis acidity of the antimony atom. While the orienta-
tion of the 2-picolinate ligands matches those found in
[Me3Sb(O2C–C5H4N)2] Æ H2O, the non-bonding atoms
approach the antimony atom at closer distances. Thus,
for the carboxylate ligand with both oxygen atoms directed
towards the antimony atom, the Sb–O distances are
A survey of the Cambridge Crystallographic Database
[15] indicated that there are 32 triorganoantimony dicar-
boxylate structures of which only four had antimony-
bound methyl substituents [16,17], the remaining having
aromatic groups bound to antimony. Of the trimethylanti-
mony structures, arguably the most relevant for compari-
˚
˚
2.185(2) A and 2.721(3) A. The other carboxylate ligand
Fig. 2. Crystal packing diagram for [Me3Sb(O2C–C5H4N)2] Æ H2O viewed down the b-axis. The hydrogen-bonds involving the lattice water molecule are
shown as blue-dashed lines. The C–Hꢀ ꢀ ꢀO contacts involving the carboxylate-O2, O4 atoms are shown as orange-dashed lines. Colour code: antimony:
orange; oxygen: red; nitrogen: blue; carbon: grey; hydrogen: green. (For interpretation of the references to colour in this figure legend, the reader is
referred to the web version of this article.)

K.R. Chaudhari et al. / Journal of Organometallic Chemistry 692 (2007) 4928–4932
4931
˚
˚
forms Sb–O, N separations of 2.099(2) A and 2.600(3) A
[17]. If the donor atoms forming the longer distances in
[Ph3Sb(O2C–C5H4N)2] are considered to be bonding, the
coordination geometry would be best described as being
based on a pentagonal bipyramid with phenyl groups occu-
pying axial positions.
3.2.3. [Et3Sb(O2C–C5H4N)2] (1c)
84% as a paste. IR in Nujol: 1650 m(CO), 550 m(Sb–C)
cmꢁ1. 1H NMR in CDCl3: 1.42 (t, 8 Hz, SbCH2CH3); 2.54
(q, 8 Hz, SbCH2); 7.34 (t, 8 Hz), 7.73 (t, 8 Hz), 8.04 (d, d,
0.8, 8.0 Hz), 8.76 (br) C5H4Nꢁ. 13C{1H}NMR in CDCl3:
9.0 (s, SbCH2CH3); 25.2 (s, SbCH2); 124.4 (C-5), 125.6
(C-3), 136.5 (C-4), 149.0 (C-6), 150.2 (C-2), 168.6 (s, C@O).
3. Experimental
3.2.4. [Et3Sb(O2C–C9H6N)2] (1d)
87% yield as paste. IR in Nujol: 1647 m (C@O), 495 m
3.1. Reagents and instrumentation
(Sb–C) cmꢁ1
.
1H NMR in CDCl3: 1.61 (t, 7.8 Hz,
All preparations involving organoantimony compounds
were performed in Schlenk flask in anhydrous condition
under a nitrogen atmosphere. Antimony trichloride,
2-picolinic acid and 2-quinaldic acid were obtained from
S.D. Fine Chemicals. Triorganostibines, R3Sb (R = Me,
Et, Pri, Ph), were obtained by the reaction of SbCl3 with
RMgX (X = Br or I) in diethylether and their oxidation
by a CCl4 solution of bromine gave corresponding
R3SbBr2. Triorganoantimony(V) isopropoxides, [R3Sb(O-
Pri)2], were prepared by the reaction of R3SbBr2 with NaO-
Pri in isopropanol–benzene and the trialkyl derivatives
were distilled under reduced pressure and their purity was
ascertained by 1H NMR spectra [18]. Infrared spectra were
recorded between CsI plates on a Bomen MB-102 FT IR
spectrophotometer. NMR spectra (1H and 13C{1H}) were
recorded on a Bruker DPX-300 spectrometer in 5 mm thin
walled NMR tube as CDCl3 solutions. Chemical shifts
are relative to internal chloroform peak (7.26 ppm and
SbCH2CH3); 2.79 (q, 7.8 Hz, SbCH2); 7.60 (t, 7 Hz, H-5),
7.78 (t, 7 Hz, H-8), 7.85 (d, 8.1 Hz, H-4); 8.20 (AB quartet,
H-6, 7); 8.45 (d, 8.5 Hz, H-3). 13C{1H}NMR in CDCl3: 9.2
(s, SbCH2CH3); 24.6 (s, SbCH2); 121.1, 127.1, 127.7, 128.8,
129.7, 130.5, 166.6, 147.5, 150.5; 168.8 (C@O).
3.2.5. [Pri3Sb(O2C–C5H4N)2] (1e)
87% yield. IR in Nujol: 1650 m(C@O), 557 m(Sb–C)
1
cmꢁ1. H NMR in CDCl3: 1.68 (d, 7.1 Hz, SbCHMe2);
3.39 (sep, 7.1 Hz, SbCH-); 7.39 (br), 7.79 (br), 8.04 (d,
7.6 Hz), 8.74 (br). 13C{1H}NMR in CDCl3: 19.7 (s,
SbCHMe2); 39.9 (s, SbCH<); 124.1(C-5), 125.2 (C-3),
136.0 (C-4), 149.4 (C-6), 150.8 (C-2), 168.9 (C@O).
3.2.6. [Pri3Sb(O2C–C9H6N)2] (1f)
94% yield, m.p. 128 ꢁC. Anal. Calc. for C29H33N2O4Sb:
C, 58.5; H, 5.6; N, 4.7. Found: C, 58.3; H, 5.3; N, 5.3%. IR
1
in Nujol: 1640 m(C@O), 538 m(Sb–C) cmꢁ1. H NMR in
1
77.0 ppm for H and 13C{1H}NMR, respectively).
CDCl3: 1.78 (d, 7.1 Hz, SbCHMe2); 3.51 (sep, 7.1 Hz,
SbCH<); 7.60 (t, 7 Hz, H-5); 7.75 (t, 7 Hz, H-8); 7.85 (d,
7.5 Hz, H-4); 8.20 (AB pattern, H-6, 7), 8.35 (d, 8.3 Hz,
H-3). 13C{1H}NMR in CDCl3: 20.2 (s, SbCHMe2); 40.4
(s, SbCH<); 121.3; 127.3, 127.8, 129.0, 129.7, 131.1,
136.7, 148.1, 151.2, (C9H6N), 169.3 (C@O).
3.2. Synthesis
3.2.1. [Me3Sb(O2C–C5H4N)2] (1a)
To a benzene solution (60 cm3) of [Me3Sb(OPri)2]
(752 mg, 2.64 mmol) was added 2-picolinic acid (649 mg,
5.28 mmol) under a nitrogen atmosphere and the whole
was stirred at room temperature for 3 h. The solvent was
evaporated under vacuum to give a colourless solid
(1.023 g, 94%). This was recrystallized from benzene–hex-
ane mixture, m.p. 136 ꢁC. Anal. Calc. for C15H17N2O4Sb:
C, 43.8; H, 4.2; N, 6.8. Found: C, 43.2; H, 4.9; N, 6.7%.
3.2.7. [Ph3Sb(O2C–C5H4N)2] (1g)
Yield 85%, m.p. 120 ꢁC. IR in Nujol: 1678 cmꢁ1m(C@O).
1H NMR in CDCl3: 7.29–7.31 (m, C6H5Sb); 7.48 (t, 7 Hz,
C5H4N); 7.79–7.88 (m, C6H5 + C5H4N); 8.14 (d, 7.8 Hz,
C5H4N); 9.22 (d, 5 Hz, C5H4N). 13C{1H}NMR in CDCl3:
125.4 (C-5), 126.6 (C-3), 129.1 (C-3, 5, Ph), 130.3 (C-4, Ph),
133.3 (C-2,6; Ph), 133.8 (Sb–C), 137.7 (C-4), 145.4 (C-6),
148.8 (C-2), 167.7 (C@O).
1
IR in Nujol: 1654 (m CO), 565 (m Sb–C) cmꢁ1. H NMR
in CDCl3: 2.09 (s, SbMe3); 7.44 (m), 7.82 (m), 8.12 (d,
7.7 Hz); 8.82 (br) (C5H4N). 13C{1H}NMR in CDCl3:
14.1(s, SbMe3); 125.0 (C–5), 126.0 (C-3), 136.8 (s) (C-4),
149.2 (s) (C-6), 150.3 (C-2); 169.0 (s, CO). All other com-
plexes were prepared similarly by the reaction between
R3Sb(OPri)2 and heterocyclic carboxylic acid.
3.2.8. [Ph3Sb(O2C–C9H6N)2] (1h)
Yield 97% m.p 131 ꢁC. IR in Nujol: 1645 cmꢁ1 m(CO).
1H NMR in CDCl3: 7.15– 8.82 (m, Ph + C9H6N).
3.2.9. [Me3Sb(Br)(O2C–C5H4N)] (2)
Reaction between Me3SbBr2(136 mg, 0.42 mmol) and
[Me3Sb(O2C–C5H4N)2] (172 mg, 0.42 mmol) in benzene
3.2.2. [Me3Sb(O2C–C9H6N)2] (1b)
98% yield, m.p 121 ꢁC. IR in Nujol: 1630 cmꢁ1 m(C@O).
1H NMR in CDCl3: 2.25 (s, Me3Sb); 7.63 (t, 7 Hz, H-5),
7.79 (t, 7 Hz, H-8), 7.87 (d, 8.1 Hz, H-4); 8.24 (AB pattern,
H-6, H-7); 8.40 (d, 8.5 Hz, H-3). 13C{1H}NMR in CDCl3:
13.2 (s, Me3Sb); 121.4, 127.4, 128.3,129.2, 130.0, 130.9,
137.0, 147.7, 150.5; 169.2 (CO).
gave
a
mixture containing [Me3Sb(O2C–C5H4N)2],
[Me3Sb(Br)(O2C–C5H4N)] and Me3SbBr2 with a relative
ratio of 1:2:1. This ratio did not change even after refluxing
1
the solution for 3 h. The trimethylantimony H NMR sig-
nals for this product in different solvents are given below:

4932
K.R. Chaudhari et al. / Journal of Organometallic Chemistry 692 (2007) 4928–4932
CDCl3: 2.06 [Me3Sb(O2C–C5H4N)2],
Supplementary data associated with this article can be
found, in the online version, at doi:10.1016/j.jorganchem.
2007.07.033.
2.37 [Me3Sb(Br)(O2C–C5H4N)]
2.61 [Me3SbBr2]
C6D6: 1.80 [Me3Sb(O2C–C5H4N)2]
1.98 [Me3Sb(Br)(O2C–C5H4N)]
2.05 [Me3SbBr2]
DMSO-d6: only one broad resonance d: 2.07.
CD3OD: only one broad resonance d: 2.25
(1/2D = 36 Hz).
References
[1] V.K. Jain, R. Bohra, R.C. Mehrotra, Struct. Bond. 52 (1982) 147.
[2] V.K. Jain, R. Bohra, R.C. Mehrotra, Inorg. Chem. Acta 51 (1981) 191.
[3] V.K. Jain, R. Bohra, R.C. Mehrotra, J. Indian Chem. Soc. 57 (1980) 408.
[4] K.W. Shen, W.E. McEwen, S.J. Placa, W.C. Hamilton, A.P. Wolf, J.
Am. Chem. Soc. 90 (1968) 1718.
[5] D.B. Sowerby, J. Chem. Res (S) (1979) 80;
H. Barucki, S.J. Coles, J.F. Costello, T. Gelbrich, M.B. Hursthouse,
J. Chem. Soc. Dalton Trans. (2000) 2319.
3.3. Crystal structure determination
[6] T.T. Bamgboye, M.J. Begley, I.G. Southerington, D.B. Sowerby, J.
Chem. Soc. Dalton Trans. (1994) 1983.
[7] V.K. Jain, J. Mason, R.C. Mehrotra, J. Organomet. Chem. 309
(1986) 45.
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E.R.T. Tiekink, J. Organomet. Chem., in press.
Crystals of [Me3Sb(O2C–C5H4N)2] Æ H2O were obtained
from the slow evaporation of a dichloromethane/hexane solu-
tionofthecompound(1a). Intensitydataforacolourlesscrys-
tal 0.03 · 0.24 · 0.32 mm3 were collected at 120 K on a
Bruker SMART APEX2 CCD using Mo Ka radiation sothat
hmax = 27.5ꢁ. The data set was corrected for absorption based
on multiple scans [19] and reduced using standard methods
[20]. The structure was solved by heavy-atom methods [21]
and refined by a full-matrix least-squares procedure on F2
with anisotropic displacement parameters for non-hydrogen
atoms, carbon-bound hydrogen atoms in their calculated
positions and a weighting scheme of the form w = 1/
[12] E. Maslowsky Jr., J. Organomet. Chem. 70 (1974) 153.
[13] V.K. Jain, J. Mason, B.S. Saraswat, R.C. Mehrotra, Polyhedron 4
(1985) 2089.
[14] Hydrogen-bonding interactions in [Me3Sb(O2C–C5H4N)2] Æ H2O: O5–
˚
˚
H1oꢀ ꢀ ꢀO3 = 2.43 A, O5ꢀ ꢀ ꢀO3 = 3.094(6) A, with an angle at H1o of
˚
˚
[r2(F0 ) + (0.060P)2 + 1.112P] where P = (F02 + 2Fc /3)
[22]. The water–hydrogen atoms were located from a
difference map and refined with O–H constrained to
2
2
137ꢁ. O5–H2oꢀ ꢀ ꢀN2 = 2.38 A, O5ꢀ ꢀ ꢀN2 = 3.096(7) A, with an angle at
˚
˚
H2o = 143ꢁ. C3–H3ꢀ ꢀ ꢀO5 = 2.53 A, C3ꢀ ꢀ ꢀO5 = 3.234(9) A, with angle
at H3 of 131ꢁ for symmetry operation: ꢁ1 + x, 1/2 ꢁ y, ꢁ1/2 + z. C4–
˚
˚
H4ꢀ ꢀ ꢀO5 = 2.46 A, C4ꢀ ꢀ ꢀO5 = 3.363(7) A with angle at H4 of 158ꢁ for
˚
˚
0.840(1) A. Fig. 1, showing the atom labelling scheme, was
symmetry operation: ꢁx, 1/2 + y, 1/2 ꢁ z. C11–H11ꢀ ꢀ ꢀO2 = 2.58 A,
˚
C11ꢀ ꢀ ꢀO2 = 3.488(8) A, with angle at H11 of 161ꢁ for symmetry
drawn with 70% displacement ellipsoids using ORTEP [23]
andFig. 2 wasdrawnwithDIAMONDwitharbitraryspheres
[24]. Data manipulation and interpretation were accom-
plished using teXsan [25] and PLATON [26]. Crystal
data for [Me3Sb(O2C–C5H4N)2]: C15H19N2O5Sb, M =
˚
operation: 1 + x, 1/2 ꢁ y, 1/2 + z. C15–C15aꢀ ꢀ ꢀO2 = 2.60 A,
˚
C15ꢀ ꢀ ꢀO2 = 3.537(7) A, with angle at H15a of 160ꢁ for symmetry
˚
operation: ꢁx, ꢁy, ꢁz. C14–H14bꢀ ꢀ ꢀO4 = 2.59 A, C14ꢀ ꢀ ꢀO4 =
˚
3.436(7) A, with angle at H14b of 144ꢁ for symmetry operation: ꢁx,
1 ꢁ y, ꢁz.
˚
[15] F.H. Allen, Acta Crystallogr. B58 (2002) 380.
429.07, monoclinic, P21/c, a = 12.2264(9) A, b = 10.1651(7)
3
˚
˚
˚
[16] C. Silvestru, I. Haiduc, E.R.T. Tiekink, D. de Vos, M. Biesemans, R.
Willem, M. Gielen, Appl. Organomet. Chem. 9 (1995) 597.
[17] M. Domagala, F. Huber, H. Preut, Z. Anorg. Allg. Chem. 582 (1990) 37.
[18] K.P. Chaudhari, P.P. Phadnis, H. Mahalakshmi, V.K. Jain, BARC/
2002/R/013.
A, c = 14.6901(8) A, b = 111.959(4)ꢁ, V = 1693.27(19) A ,
Z = 4, Dx = 1.683 g cmꢁ3, l = 1.655 mmꢁ1, R (2580 data
with I P 2r(I)) = 0.040, wR = (all 3874 data) = 0.126.
[19] G.M. Sheldrick, SADABS. Version 2.10, University of Go¨ttingen,
Germany, 2003.
Acknowledgements
[20] Z. Otwinowski, W. Minor, in: C.W. CarterJr., R.M. Sweet (Eds.),
Methods in Enzymology, Macromolecular Crystallography, Part A,
vol. 276, Academic Press, New York, 1997, pp. 307–326.
[21] P.T. Beurskens, G. Admiraal, G. Beurskens, W.P. Bosman, S.
Garcia-Granda, J.M.M. Smits, C. Smykalla, The DIRDIF program
system, Technical Report of the Crystallography, Laboratory, Uni-
versity of Nijmegen, Nijmegen, The Netherlands, 1992.
[22] G.M. Sheldrick, SHELXS97Program for the Solution of Crystal
Structure, University of Go¨ttingen, Germany, 1997.
[23] C.K. Johnson, ORTEP II, Report ORNL-5136, Oak Ridge National
Laboratory, Oak Ridge, TN, 1976.
[24] Crystal Impact. DIAMOND. Version 3.1. Crystal Impact GbR,
Postfach 1251, D-53002 Bonn, Germany, 2006.
[25] teXsan, Structure Analysis Package, Molecular Structure Corpora-
tion, Houston, TX, 1992.
[26] A.L. Spek, PLATONA Multipurpose Crystallographic Tool, Utrecht
University, Utrecht, The Netherlands, 2006.
We thank Drs. T. Mukherjee and D. Das for encourage-
ment of this work. X-ray data for the structure were col-
lected at the EPSRC X-ray Crystallographic Service,
University of Southampton, England; the authors thank
the staff of the Service for help and advice.
Appendix A. Supplementary material
CCDC 649446 contains the supplementary crystallo-
graphic data for this paper. These data can be obtained free
of charge via http://www.ccdc.cam.ac.uk/conts/retriev-
ing.html, or from the Cambridge Crystallographic Data
Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax:
(+44) 1223-336-033; or e-mail: deposit@ccdc.cam.ac.uk.