Hexacoordinate triphenylantimony(V) complex with tridentate bis-(3,5-di-tert-butyl-phenolate-2-yl)-amine ligand: Synthesis, NMR and X-ray study

Article abstract of DOI:10.1016/j.jorganchem.2008.08.002

The oxidative addition reaction of 4,6-di-tert-butyl-N-(2-hydroxy-3,5-di-tert-butyl-phenyl)-o-iminobenzoqui none (IBQ) to triphenylantimony(III) proceeds with the migration of hydroxyl-proton to a nitrogen atom to form tridentate O,N,O′-coordinated bis-(3,5-di-tert-butyl-phenolate-2-yl)-amine ligand. In accordance with ¹H, ¹³C, DEPT NMR data, the new hexacoordinate complex [bis-(3,5-di-tert-butyl-phenolate-2-yl)-amine]triphenylantimony(V), [(AP-AP)H]SbPh₃ (1) in solution has a C_s symmetry plane leading to the equivalence of two O,N-chelate o-aminophenolato moieties. The molecular structure of 1 · acetone was studied by a single-crystal X-ray. Compound 1 was found to be air-stable both in solid and in solution. Its oxidation by PbO₂ leads to paramagnetic [4,6-di-tert-butyl-N-(3,5-di-tert-butyl-phenolate-2-yl)-o-iminobenzosemi quinolato]triphenylantimony(V), [(AP-ISQ)]SbPh₃ (2).

Full text of DOI:10.1016/j.jorganchem.2008.08.002

Journal of Organometallic Chemistry 693 (2008) 3451–3455
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Journal of Organometallic Chemistry
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Note
Hexacoordinate triphenylantimony(V) complex
with tridentate bis-(3,5-di-tert-butyl-phenolate-2-yl)-amine ligand:
Synthesis, NMR and X-ray study
b
a
a
a
Andrey I. Poddel’sky a, , Nikolay V. Somov , Yury A. Kurskii , Vladimir K. Cherkasov , Gleb A. Abakumov
*
a G.A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences, Tropinina 49, 603950 Nizhniy Novgorod, GSP-445, Russia
b Nizhniy Novgorod State University, Physical Faculty, Building 3, Gagarina Avenue 23, 603950 Nizhniy Novgorod, Russia
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 16 May 2008
Received in revised form 28 July 2008
Accepted 5 August 2008
Available online 11 August 2008
The oxidative addition reaction of 4,6-di-tert-butyl-N-(2-hydroxy-3,5-di-tert-butyl-phenyl)-o-imi-
nobenzoquinone (IBQ) to triphenylantimony(III) proceeds with the migration of hydroxyl-proton to a
nitrogen atom to form tridentate O,N,O0-coordinated bis-(3,5-di-tert-butyl-phenolate-2-yl)-amine ligand.
In accordance with 1H, 13C, DEPT NMR data, the new hexacoordinate complex [bis-(3,5-di-tert-butyl-phe-
nolate-2-yl)-amine]triphenylantimony(V), [(AP-AP)H]SbPh3 (1) in solution has a Cs symmetry plane lead-
ing to the equivalence of two O,N-chelate o-aminophenolato moieties. The molecular structure of
1 ꢀ acetone was studied by a single-crystal X-ray. Compound 1 was found to be air-stable both in solid
and in solution. Its oxidation by PbO2 leads to paramagnetic [4,6-di-tert-butyl-N-(3,5-di-tert-butyl-phe-
nolate-2-yl)-o-iminobenzosemiquinolato]triphenylantimony(V), [(AP-ISQ)]SbPh3 (2).
Keywords:
Antimony(V)
ONO ligands
NMR spectroscopy
EPR spectroscopy
X-ray diffraction
Ó 2008 Elsevier B.V. All rights reserved.
1. Introduction
[4a,c]. The modification of AP ligand with an insertion of third
coordinating hydroxy group, as we will show in the present paper,
The chemistry of organoantimony compounds has been an area
of extensive research for more than four decades [1]. The reason to
investigate these compounds is their application in the organic
synthesis and catalysis [2], as the potential agents in biochemistry
and medicine [3]. Recently, some antimony(V) complexes with
catecholate/o-amidophenolate, (Cat)SbPh3/(AP)SbPh3, ligands were
found to bind the molecular oxygen in a reversible manner [4] that
suggests their potentiality in different oxidation processes and
modeling biological systems [5]. Such unique ability of these com-
plexes is liable to the presence of redox-active catecholate/o-
amidophenolate ligand coupled with the heavy antimony atom
having: (i) a large spin–orbital interaction constant, and (ii) a free
coordination site to coordinate superoxide anion formed from O2.
The mechanism of this interaction discussed in [4a,c] includes
the step of the one-electron oxidation of dianionic Cat/AP ligand
by dioxygen that imposes a limitation on the first redox-potential
range of ligand. In work [6], we have shown that triphenylantimo-
ny(V) catecholates with electron withdrawing groups are inert to-
ward molecular oxygen. On the other hand, triphenylantimony(V)
4,6-di-tert-butyl-N-aryl-o-amidophenolates (AP)SbPh3 show the
high dioxygen reactivity forming the stable spiroendoperoxides
causes the distinctive structure and, as a result, behaviour of triph-
enylantimony(V) complex formed. Here we are describing the syn-
thesis and structure of new triphenylantimony(V) complex with
O,N,O0-coordinated tridentate bis-(3,5-di-tert-butyl-phenolate-2-
yl)-amine ligand.
2. Experimental
2.1. Synthesis
All reagents were grade. Solvents were purified following stan-
dard methods [7]. The ligand 4,6-di-tert-butyl-N-(2-hydroxy-3,5-
di-tert-butyl-phenyl)-o-iminobenzoquinone (IBQ) was prepared
according literature procedure [8].
Hexacoordinate [bis-(3,5-di-tert-butyl-phenolate-2-yl)-amine]-
triphenylantimony(V) (1) was prepared from triphenylstibine and
IBQ in hexane solution. The sample of SbPh3 (0.353 g, 1.0 mmol)
was dissolved in deaerated dry hexane (20 ml) and to this colorless
solution the hexane solution (30 ml) of IBQ (0.423 g, 1.0 mmol)
was added dropwise. Deep blue–violet color of solution (the color
of initial IBQ) gradually disappeared reaching lilac coloration. After
storing at 0 °C for a day, the colorless residue was collected, filtered
off. Recrystallization of this crude product from another hexane
portion gave colorless microcrystalline powder in 95% yield. Com-
pound 1 is air-stable.
* Corresponding author. Tel.: +7 831 462 76 82; fax: +7 831 462 74 97.
E-mail address: aip@iomc.ras.ru (A.I. Poddel’sky).
0022-328X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2008.08.002

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A.I. Poddel’sky et al. / Journal of Organometallic Chemistry 693 (2008) 3451–3455
Elemental Anal. Calc. for C46H56NO2Sb: C, 71.13; H, 7.27; Sb,
3. Results and discussion
15.68; N, 1.80. Found: C, 71.19; H, 7.25; Sb, 15.37; N, 1.85%.
IR data (nujol, m
, cmꢁ1): 3307 m, 1605 w, 1570 w, 1530 w, 1481
3.1. Synthesis and characterization
s, 1433 s, 1410 m, 1362 m, 1334 w, 1301 s, 1281 s, 1263 m, 1237 w,
1202 w, 1181 w, 1165 w, 1123 w, 1076 m, 1071 m, 1061 m, 1023
w, 997 w, 983 s, 934 w, 904 m, 893 w, 871 m, 854 w, 835 s, 809 w,
780 m, 762 w, 748 m, 727 s, 693 s, 671 m, 656 w, 644 w, 598 w,
586 w, 525 w, 512 w, 478 w, 459 m, 449 w.
Ligand
4,6-di-tert-butyl-N-(2-hydroxy-3,5-di-tert-butyl-phe-
nyl)-o-iminobenzoquinone (IBQ) was prepared by a previously re-
ported method [8] from 3,5-di-tert-butyl-o-benzoquinone and 4,6-
di-tert-butyl-o-aminophenol. Its reaction with triphenylstibine in
hexane solution gives pale lilac solution. After a cooling of resulting
solution the colorless powder was obtained. In accordance with
previous experience [4,6] one can expect the formation of O,N,O0-
coordinated o-amidophenolato derivative of triphenylantimony(V)
containing hydroxy-group coordinated to central antimony atom
(Scheme 1). But we have found this product to be triphenylantimo-
ny(V) complex 1 with O,N,O0-coordinated bis-(3,5-di-tert-butyl-
phenolate-2-yl)-amine dianion (Scheme 1).
1H NMR (CDCl3, d, ppm): 1.21 (s, 18H, 2 tBu), 1.29 (s, 18H, 2
tBu), 5.49 (s, 1H, N–H), 7.03 and 7.13 (both d, both 2H, arom.
4
C6H2, JH,H = 2.26 Hz), 7.08–7.28 (mult., 4H, o-H of 2 Ph), 7.32–
7.42 (mult., 6H, m- and p-H of 2 Ph), 7.42–7.50 (mult., 3H, m-
and p-H of 1 Ph) and 7.98–8.08 (mult., 2H, o-H of 1 Ph).
13C NMR (CDCl3, d, ppm): 29.39 (2C(CH3)3), 31.57 (2C(CH3)3),
34.11 (2C(CH3)3), 35.13 (2C(CH3)3), 117.87, 122.58, 127.95,
128.29, 129.10, 129.60, 134.45, 134.67, 137.13, 138.24, 140.72,
144.64, 150.79.
IR spectrum of 1 in nujol contains the band of stretching vibra-
13C DEPT NMR (CDCl3, d, ppm): 29.39 (2C(CH3)3), 31.57
(2C(CH3)3), 117.87, 122.58, 127.95, 128.29, 129.10, 129.60,
134.45, 134.67.
tions of N–H group at 3307 cmꢁ1 1H NMR spectrum of 1 reveals
.
proton of NH group at d = 5.49 ppm (Fig. 1). According to the
NMR spectral data, complex 1 in solution has a symmetrical struc-
ture with a symmetry plane. Fig. S1 of Supplementary information
2.2. Physical measurements
IR spectra were monitored in the 400–4000 cmꢁ1 range by a
FSM 1201 Fourier-IR spectrometer in nujol. X-band EPR spectral
investigations were performed on Bruker ER 200 D-SRC spec-
trometer with ER041 MR microwave bridge, ER 4105 DR double
resonator and ER 4111 VT variable temperature unite. 1H, 13C,
13C DEPT NMR-spectra were registered using Bruker AVANCE
DPX-200 spectrometer (with a TMS as internal reference and CDCl3
as solvent).
tBu
O
SbPh3
tBu
N
OH
tBu
tBu
tBu
The crystals of 1 suitable for X-ray diffraction analysis were
grown using a prolonged recrystallization of 1 from acetone as
the acetone solvate 1 ꢀ C3H6O.
O
N
+
SbPh3
tBu
tBu
O
Intensity data were collected on Oxford Diffraction (Gemini S)
OH
diffractometer with graphite monochromated Mo K
a radiation
SbPh3
O
(k = 0.71073 Å) in the /– scan mode ( = 0.3°, 10 s on each
x
x
tBu
HN
tBu
tBu
frame). The crystal structure was solved and refined by WINGX
v1.70.01 program [9]. All non-hydrogen atoms were refined with
anisotropic correction. The one/some part of H atoms were placed
in calculated positions and refined in the ‘‘riding-model”
(Uiso(H) = 1.2Ueq(carbon) Å2 for aromatic hydrogen and 1.5Ueq(car-
bon) Å2 for alkyl hydrogen), and the another part were located
from Fourier synthesis and refined isotropically [9].
IBQ
tBu
tBu
1
[(AP-AP)H]SbPh3
Scheme 1. Complex 1 is soluble in THF, toluene, but weakly soluble in alkanes.
Fig. 1. The 1H NMR spectrum of complex 1 (CDCl3, 200 MHz).

A.I. Poddel’sky et al. / Journal of Organometallic Chemistry 693 (2008) 3451–3455
3453
tBu
tBu
tBu
O
O
tBu
tBu
O
O
tBu
tBu
O
O
tBu
tBu
PbO2
HN
tBu
SbPh3
N
SbPh3
N
SbPh3
tBu
tBu
[AP-ISQ]SbPh3
2
Scheme 2.
represents 13C NMR and 13C DEPT NMR spectra of 1 with the cor-
relation of signals to the specified carbon atoms. The 1H–1H COSY
spectrum in the region 6.92–8.20 ppm useful for the signal assign-
ment is depicted in Fig. S2.
in other o-iminobenzosemiquinonato radical complexes [10] evi-
dences the unpaired electron delocalization over both aromatic cy-
cle fragments of ligand (Scheme 2).
The air-stability of complex 1 is explained by the following rea-
soning: (i) Cat and AP antimony(V) complexes reacting with
molecular oxygen [4] have a free coordination site of central anti-
mony atom to coordinate –O–O group; (ii) they can form the stable
o-semiquinonato (o-iminosemiquinonato) radical-anion as re-
quired by the mechanism proposed [4a]. In the case of 1, antimony
atom has no vacant coordination site and [(AP–AP)H]2ꢁ ligand can-
not form stable delocalized radical-anionic structure without being
deprotonated that is confirmed by EPR experiment with the oxida-
tion of 1 with lead(IV) oxide.
The protons of four tert-butyl groups give rise to two singlets at
d = 1.21 and 1.29 ppm in the 1H NMR spectrum of 1 indicating their
pair equivalence. Four aromatic protons of aminophenolate frag-
ments appear as two doublets centered at d = 7.03 and 7.13 ppm
4
(with JH,H = 2.26 Hz). The 1H and 13C NMR show the equivalency
of two phenyl groups, while third phenyl differs from those ones.
Unlike o-amidophenolate complexes [4a,c], complex 1 was
found to be air-stable: it left unchanged on the exposition to air
within several weeks. Even its oxidation with lead(IV) oxide pro-
ceeds slowly and leads to the loss of amine hydrogen by this com-
plex to yield paramagnetic compound 2 (Scheme 2). X-band EPR
spectrum of 2 toluene solution (Fig. 2) is a multiplet with
giso = 2.0039. The hyperfine structure (HFS) is caused by unpaired
electron splitting on nitrogen (14N, I = 1, 99.64%), two pairs of pro-
tons (1H, I = 1/2, 99.99%) of paramagnetic ligand, and magnetic
antimony nuclei (121Sb, I = 5/2, 57.25%, gN = 1.34550; 123Sb, I = 7/
2, 42.75%, gN = 0.72876). Due to moderate linewidth (>3 G) and a
substantial number of magnetic nuclei involved, the precise HFS
constant determination is difficult, but the estimated from com-
puter simulation HFS constants are AN (1N) ꢂ 7.1 G, AH (2H) ꢂ
3.1 G, AH (2H) ꢂ 1.5 G, A (121Sb) ꢂ 12.2 G, A (123Sb) ꢂ 6.6 G. The
HFS on two protons’ pairs with approximately two times less than
3.2. X-ray structure
Crystals of 1 suitable for a single crystal structural analysis were
grown from acetone as the acetone solvate 1 ꢀ C3H6O. Table 1
Table 1
Crystallographic data of 1 ꢀ C3H6O
Empirical formula
Formula weight
Temperature, K
Wavelength, Å
Crystal system
Space group
Unit cell dimensions
a (Å)
C49H62NO3Sb
834.75
298(2)
0.71073
Triclinic
ꢀ
P1
10.1118(8)
b (Å)
c (Å)
13.5373(13)
18.3274(19)
79.614(8)
a
(°)
b (°)
75.726(8)
c
(°)
69.369(8)
2263.3(4)
Volume, Å3
Z
2
Dcalc, mg/m3
1.225
0.649
876
0.16 ꢃ 0.08 ꢃ 0.05
2.95–28.28
99.7
11204
6356 [Rint = 0.0374]
SADABS
0.9775; 0.9305
Full-matrix least-squares on F2
11204/0/491
R1 = 0.0293, wR2 = 0.0492
R1 = 0.0662, wR2 = 0.0550
0.777
Absorption coefficient, mmꢁ1
F(000)
Crystal size, mm3
h Range for data collection (°)
Completeness to h = 28.28 (%)
Reflections collected
Independent reflections
Absorption correction
Maximum and minimum transmission
Refinement method
Data/restraints/parameters
Final R indices [I > 2
r(I)]
R indices (all data)
Goodness-of-fit on F2
Largest difference in peak and hole, e Åꢁ3
0.746 and ꢁ0.315
Fig. 2. X-band EPR of 2 (toluene, 298 K).

3454
A.I. Poddel’sky et al. / Journal of Organometallic Chemistry 693 (2008) 3451–3455
Table 2
Selected bond distances (Å) and bond angles (°) in 1 ꢀ (CH3)2CO
Sb(1)–O(1)
Sb(1)–O(2)
Sb(1)–N(1)
Sb(1)–C(13)
Sb(1)–C(19)
Sb(1)–C(25)
O(1)–C(1)
O(2)–C(7)
O(3)–C(47)
N(1)–C(6)
N(1)–C(12)
C(1)–C(2)
C(1)–C(6)
C(2)–C(3)
C(3)–C(4)
C(4)–C(5)
C(5)–C(6)
C(7)–C(8)
2.0491(12)
2.0739(11)
2.3229(16)
2.107(2)
2.1574(19)
2.1592(17)
1.333(2)
1.337(2)
1.209(2)
1.462(2)
1.458(2)
1.415(2)
1.386(2)
1.381(3)
1.385(3)
1.390(2)
1.374(2)
1.415(2)
1.387(2)
1.380(3)
1.383(3)
1.393(2)
1.363(2)
O(1)–Sb(1)–O(2)
O(1)–Sb(1)–C(13)
O(2)–Sb(1)–C(13)
O(1)–Sb(1)–C(19)
O(2)–Sb(1)–C(19)
C(13)–Sb(1)–C(19)
O(1)–Sb(1)–C(25)
O(2)–Sb(1)–C(25)
C(13)–Sb(1)–C(25)
C(19)–Sb(1)–C(25)
O(1)–Sb(1)–N(1)
O(2)–Sb(1)–N(1)
C(13)–Sb(1)–N(1)
C(19)–Sb(1)–N(1)
C(25)–Sb(1)–N(1)
C(12)–N(1)–C(6)
C(12)–N(1)–Sb(1)
C(6)–N(1)–Sb(1)
C(1)–O(1)–Sb(1)
C(7)–O(2)–Sb(1)
82.19(5)
89.36(6)
90.38(6)
164.17(6)
87.69(6)
102.91(8)
90.25(6)
168.29(6)
98.50(7)
97.66(7)
76.49(5)
74.02(5)
160.07(6)
89.06(7)
95.58(6)
113.54(14)
104.62(10)
107.20(11)
118.96(11)
114.85(10)
C(7)–C(12)
C(8)–C(9)
C(9)–C(10)
C(10)–C(11)
C(11)–C(12)
represents the crystal data collection and structure refinement
data. The selected bond lengths and angles are listed in Table 2.
Central antimony atom Sb(1) adopts a slightly distorted octahe-
dral geometry (Fig. 3). The angles between the axially positioned
atoms equal to 164.17(6)°, 168.29(6)° and 160.07(6)° (angles
C(13)–Sb(1)–N(1), O(2)–Sb(1)–C(25) and O(1)–Sb(1)–C(19) corre-
spondingly). The sums of bond angles in the plane orthogonal to
the corresponding directions are 357.79°, 357.82° and 358.48°,
respectively.
The geometrical parameters in two aromatic tBu2C6H2O (o-
aminophenolato) moieties in O,N,O0-coordinated ligand are nearly
equal within the experimental error. The angle between two hyp-
othetic planes formed by two o-aminophenolato moieties is 70.3°.
Six-membered carbon cycles C(1–6) and C(7–12) are of aromatic
character without the o-quinoid distortion typical for O,N-(O,O-)
coordinated o-iminobenzosemiquinones [10] (o-semiquinones
[11]). The oxygen-to-carbon bonds O(1)–C(1), O(2)–C(7) of
1.333(2) and 1.337(2) Å are shorter than the ordinary O–C bonds
in different triphenylantimony catecholates or o-amidophenolates
[4,12]. For example, these bonds are av. 1.356(2) Å and av.
1.361(2) Å in catecholates (4-MeO-3,6-DBCat)SbPh3 ꢀ CH3OH and
Fig. 3. Platon view [16] of 1. The H atoms (except H(1)) are omitted for clarity.
(4,5-(MeO)2-3,6-DBCat)SbPh3 ꢀ CH3CN, respectively [4b]; 1.351(4)
Å in o-amidophenolate (AP-iPr)SbPh3 [4a] (4-MeO-3,6-DBCat is
4-methoxy-3,6-di-tert-butyl-catecholate, 4,5-(MeO)2-3,6-DBCat is
4,5-dimethoxy-3,6-di-tert-butyl-catecholate, and AP–iPr is 4,6-di-
tert-butyl-N-(2,6-di-iso-propylphenyl)-o-amidophenolate).
The nitrogen atom N(1) is sp3-hybridized and tetracoordinated;
the sum of bond angles between N(1) and non-hydrogen atoms
C(6), C(12), Sb(1) is 325.36°. The significant difference in Sb–N
bond length in 1 (Sb(1)–N(1), 2.3229(16) Å) and, for example, in
(AP–iPr)SbPh3 (Sb–N, 2.041(3) Å [4a]) reflects the difference in
bond nature between the neutral donor–acceptor amino-functions
in 1 and the valence bound amide-group in (AP–iPr)SbPh3. Note-
worthy, this bond Sb(1)–N(1) in 1 is themselves the shortest
among those bonds in structurally characterized antimony
complexes with the related O,N,O0-ligands such as [
C6H4O)2]Sb}4( 3-O)2 (2.723(7) and 2.684(8) Å), {{[
c
3-PhN(o-
c
l
3-N(o-
Fig. 4. The presentation of the unit cell of 1 (left) and its rotation about horizontal line to 180° (right). The H atoms (except H(1)) and carbons of tert-butyl groups are omitted
for clarity.

A.I. Poddel’sky et al. / Journal of Organometallic Chemistry 693 (2008) 3451–3455
(b) W. Levason, G. Reid, Coord. Chem. Rev. 250 (2006) 2565–2594;
3455
C6H4OH)(o-C6H4O)2]Sb}2(l2-O)}2 (2.601(2) and 2.619(2) Å),
(c) S.S. Garje, V.K. Jain, Coord. Chem. Rev. 236 (2003) 35–56;
(d) S. Schulz, Coord. Chem. Rev. 215 (2001) 1–37;
and O,N,O0,O00-ligands such as
(2.433(2) Å) [13].
[c
4-N(o-C6H4O)3]Sb(OSMe2)
(e) H.J. Breunig, R. Rösler, Chem. Soc. Rev. 29 (2000) 403–410;
(f) N.R. Champness, W. Levason, Coord. Chem. Rev. 133 (1994) 115–217;
(g) C. Silvestru, I. Haiduc, Coord. Chem. Rev. 147 (1996) 117–146;
(h) H.P.S. Chauhan, Coord. Chem. Rev. 173 (1998) 1–30.
[2] (a) J.P. Finet, Ligand Coupling Reactions with Heteroatomic Compounds,
Pergamon, New York, 1998. p. 308;
The coordination of N(1) to antimony atom elongates the dis-
tances N(1)–C(6) and N(1)–C(12) with aromatic carbon rings
(1.462(2) and 1.458(2) Å, respectively) compared with the usual
C(aryl)ꢁNH(sp3,pyramidal) bonds (1.41–1.43 Å) [14].
(b) D.V. Moiseev, A.V. Gushchin, A.S. Shavirin, Y.A. Kursky, V.A. Dodonov, J.
Organomet. Chem. 667 (2003) 176;
(c) K. Matoba, S. Motofusa, C.S. Cho, K. Ohe, S. Uemura, J. Organomet. Chem.
574 (1999) 3;
(d) C.S. Cho, K. Tanabe, O. Itoh, S. Uemura, J. Org. Chem. 60 (1995) 274;
(e) L.-J. Zhang, X.-S. Mo, J.-Z. Huang, Y.-Z. Huang, Tetrahedron Lett. 34 (1993)
1621–1624;
The antimony-to-carbon bonds differ from each other reflecting
trans-effect: Sb(1)–C(19) and Sb(1)–C(25) (2.1574(19) and
2.1592(17) Å) of phenyl groups trans-positioned toward oxygen
atoms are ꢄ0.02–0.04 Å longer than those bonds in catecholates
[4b,c], while the third Sb(1)–C(13) bond (2.107(2) Å) which is
trans-located to a donor–acceptor Sb(1)–N(1) bond lies in the com-
mon range of Sb–C(phenyl) bonds (2.10–2.13 Å).
(f) A.B. Goel, H.J. Richards, J.H. Kyung, Tetrahedron Lett. 25 (1984) 391;
(g) A.B. Goel, H.J. Richards, J.H. Kyung, Inorg. Chim. Acta 76 (1983) L95.
[3] (a) Guo-Cang Wang, Yong-Na Lu, Jian Xiao, Lin Yu, Hai-Bin Song, Jin-Shan Li,
Jing-Rong Cui, Rui-Qing Wang, Fu-Xiang Ran, J. Organomet. Chem. 690 (2005)
151–156;
Worthy of note is that, if complex 1 in solution has a symmet-
rical structure, as it shown above by NMR spectroscopy, in crystal
such symmetry is broken. Antimony–oxygen bond distances differs
by ꢄ0.025 Å (see Table 2). The geometries of the five-membered
chelate metallocycles SbOOCC (the chelate rings) are not planar
and non-equivalent. The bend angles along the O(1)ꢀ ꢀ ꢀN(1) and
O(2)ꢀ ꢀ ꢀN(1) lines in two parts of 1 are 6.27° and 30.93°, respec-
tively. The corresponding dihedral angles O(1)–C(1)–C(6)–N(1)
and O(2)–C(7)–C(12)–N(1) are 5.07° and 2.85°. This fact of non-
equivalence may be rationalized by crystal packing effect and, in
addition, by the solvation of acetone molecule to 1.
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As mentioned above, in the crystals of 1 ꢀ (CH3)2CO each com-
plex molecule is solvated with acetone molecule coordinated to
the hydrogen H(1) of NH-group (Fig. 4). The distance O(3)ꢀ ꢀ ꢀ
H(1)N(1) is 2.235(3) Å, being shorter than the sum of O and H
van der Waals radii (1.5 + 1.2 = 2.7 Å) [15]. Meanwhile, the
O(3)ꢀ ꢀ ꢀN(1) distance (3.016(3) Å) is close to the value of normal
van der Waals Oꢀ ꢀ ꢀN contact (3.1 Å) [15].
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We should note that the unit cell (Fig. 4) contain two complex 1
molecules which are enantiomers in their distortion.
Acknowledgements
We are grateful to the Russian Foundation for Basic Research
(Grant 07-03-00819), President of Russian Federation (Grants
MK-3523.2007.3 and NSh-4182.2008.3) and Russian Science Sup-
port Foundation (A.I. Poddel’sky) for financial support of this work.
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(1987) 163–168;
Appendix A. Supplementary material
CCDC 686968 contains the supplementary crystallographic data
for 1 ꢀ acetone. These data can be obtained free of charge from the
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif. Supplementary information contains 13C NMR,
DEPT (Fig. S1) and 1H–1H COSY (Fig. S2) spectra. Supplementary
data associated with this article can be found, in the online version,
at doi:10.1016/j.jorganchem.2008.08.002.
(c) G.K. Fukin, L.N. Zaharov, G.A. Domrachev, A.Yu. Fedorov, S.N. Zaburdyaeva,
V.A. Dodonov, Russ. Chem. Bull. 48 (1999) 1722–1732;
(d) V.K. Cherkasov, E.V. Grunova, A.I. Poddel’sky, G.K. Fukin, Yu.A. Kurskii, L.G.
Abakumova, G.A. Abakumov, J. Organomet. Chem. 690 (2005) 1273–1281;
(e) G.A. Abakumov, N.N. Vavilina, Yu.A. Kurskii, L.G. Abakumova, G.K. Fukin,
V.K. Cherkasov, A.S. Shavyrin, E.V. Baranov, Russ. Chem. Bull. 56 (2007) 1813–
1820.
[13] J.M. Tanski, B.V. Kelly, G. Parkin, Dalton Trans. (2005) 2442–2447.
[14] D.R. Lide (Ed.), Handbook of Chemistry and Physics, 84th ed., CRC Press, 2003–
2004, pp. 6–9.
[15] S.S. Batsanov, Russ. J. Inorg. Chem. 36 (1991) 3015.
[16] A.L. Spek, PLATON A Multipurpose Crystallographic Tool, Utrecht University,
2000.
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