Preparation and structural organisation of heteroleptic tetraphenylantimony(V) complexes comprising unidentately and bidentately coordinated O,O′-dialkyldithiophosphate groups: Multinuclear (13C, 31P) CP/MAS NMR and single-crystal X-ray diffraction studies

Article abstract of DOI:10.1016/j.ica.2007.02.044

O,O′-dipropyldithiophosphate and O,O′-di-iso-butyldithiophosphate (Dtph) tetraphenylantimony(V) complexes of the general formula [Sb(C₆H₅)₄{S₂P(OR)₂}] (R = C₃H₇, i-C₄H₉) were prepared and studied by means of ¹³C, ³¹P CP/MAS NMR spectroscopy and single-crystal X-ray diffraction. Distorted octahedral and trigonal bipyramidal molecular structures have been established for prepared complexes. These unexpected structural distinctions between chemically related compounds are defined by the principally different coordination modes of O,O′-dipropyldithiophosphate and O,O′-di-iso-butyldithiophosphate ligands in their molecular structures (i.e., S,S′-bidentate chelating and S-unidentately coordinated, respectively). To characterise quantitatively phosphorus sites in both species of dithiophosphate ligands, ³¹P chemical shift anisotropy parameters (δ_aniso and η) were calculated from spinning sideband manifolds in MAS NMR spectra. The ³¹P chemical shift tensors for the bidentate chelating and unidentately coordinated dithiophosphate ligands display a profoundly rhombic and nearly axially symmetric characters, respectively.

Full text of DOI:10.1016/j.ica.2007.02.044

Inorganica Chimica Acta 360 (2007) 2897–2904
www.elsevier.com/locate/ica
Preparation and structural organisation of heteroleptic
tetraphenylantimony(V) complexes comprising unidentately and
bidentately coordinated O,O0-dialkyldithiophosphate
groups: Multinuclear (13C,31P) CP/MAS NMR and
single-crystal X-ray diffraction studies
a
b
c
a,
*
Maxim A. Ivanov , Oleg N. Antzutkin , Vladimir V. Sharutin , Alexander V. Ivanov
,
c
d
b
Antonya P. Pakusina , Mikhail A. Pushilin , Willis Forsling
a
Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences, 675000 Blagoveschensk, Amur Region, Russia
b
˚ ˚
Division of Chemistry, Lulea University of Technology, S-97187 Lulea, Sweden
c
Blagoveschensk State Pedagogical University, 675000 Blagoveschensk, Amur Region, Russia
Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 690022 Vladivostok, Russia
d
Received 2 August 2006; accepted 7 February 2007
Available online 12 March 2007
Abstract
O,O0-dipropyldithiophosphate and O,O0-di-iso-butyldithiophosphate (Dtph) tetraphenylantimony(V) complexes of the general for-
mula [Sb(C6H5)4{S2P(OR)2}] (R = C3H7, i-C4H9) were prepared and studied by means of 13C, 31P CP/MAS NMR spectroscopy and
single-crystal X-ray diffraction. Distorted octahedral and trigonal bipyramidal molecular structures have been established for prepared
complexes. These unexpected structural distinctions between chemically related compounds are defined by the principally different coor-
dination modes of O,O0-dipropyldithiophosphate and O,O0-di-iso-butyldithiophosphate ligands in their molecular structures (i.e., S,S0-
bidentate chelating and S-unidentately coordinated, respectively). To characterise quantitatively phosphorus sites in both species of
dithiophosphate ligands, 31P chemical shift anisotropy parameters (daniso and g) were calculated from spinning sideband manifolds in
MAS NMR spectra. The 31P chemical shift tensors for the bidentate chelating and unidentately coordinated dithiophosphate ligands
display a profoundly rhombic and nearly axially symmetric characters, respectively.
ꢀ 2007 Elsevier B.V. All rights reserved.
Keywords: Heteroleptic dialkyldithiophosphate tetraphenylantimony(V) complexes; Molecular structures; 13C, 31P CP/MAS NMR spectroscopy; 31P
chemical shift anisotropy; Single-crystal X-ray diffraction
1. Introduction
Therefore, syntheses of new organoantimony compounds
and studies of their structures and properties are of interest
in modern coordination chemistry. Recently, we reported
the preparation, heteronuclear (13C, 15N) CP/MAS NMR
and structural studies of polycrystalline heteroleptic N,N-
Organoantimony compounds are of interest as biocides,
fungicides, catalyst components and antioxidants [1].
dialkyldithiocarbamate
tetra-p-tolylantimony(V)
and
*
Corresponding author. Tel.: +07 4162 527232; fax: +07 4162 534618.
tetraphenylantimony(V) complexes of the general formulas
[Sb(p-CH3–C6H4)4(S2CNR2)] and [Sb(C6H5)4(S2CNR2)],
where R = CH3, C2H5, C3H7 and R2 = (CH2)6 [2–4]. Dis-
torted octahedral molecular structures with S,S0-bidentate
E-mail addresses: Oleg.Antzutkin@ltu.se (O.N. Antzutkin), vvsharu-
tin@rambler.ru (V.V. Sharutin), alexander.v.ivanov@chemist.com (A.V.
Ivanov), pumalych@ich.dvo.ru (M.A. Pushilin), Willis.Forsling@ltu.se
(W. Forsling).
0020-1693/$ - see front matter ꢀ 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2007.02.044

2898
M.A. Ivanov et al. / Inorganica Chimica Acta 360 (2007) 2897–2904
coordination mode of N,N-dialkyldithiocarbamate ligands
were established for all named heteroleptic complexes.
Moreover, in the unit cell of [Sb(C6H5)4{S2CN(CH2)6}],
two molecular forms of this complex, which are related
to each other as conformational isomers, have been discov-
ered using single-crystal X-ray diffraction analysis. Besides
that, 13C and 15N resonance lines were assigned to the
structural positions of corresponding atoms in the @N–
C(S)S– groups of both conformers.
rally and recrystallised from benzene–heptane (1:1)
solutions. Both heteroleptic tetraphenylantimony(V) com-
pounds 1 and 2, as well as the original potassium salts,
were comparatively characterised on solid state 13C CP/
MAS NMR data (d, ppm):
[Sb(C6H5)4{S2P(OC3H7)2}] (1): 149.4, 136.6, 134.9, 132.9,
131.6, 130.5, 129.5, 128.6 (C6H5–); 66.7, 65.7 (1:1, –OCH2–);
25.3, 24.8 (1:1, –CH2–); 11.9, 10.0 (1:1, –CH3). Cf. data for
the original K{S2P(OC3H7)2}: 71.7, 68.9, 68.8 (2:1:1, –
OCH2–); 25.0, 24.1 (1:1, –CH2–); 10.2, 9.9, 8.9 (1:2:1, –CH3).
This article reports the preparation, multinuclear (31P,
13C) CP/MAS NMR and single-crystal X-ray diffraction
studies on two novel heteroleptic tetraphenylantimony(V)
complexes, [Sb(C6H5)4{S2P(OR)2}] (where R = C3H7 (1)
and i-C4H9 (2)) comprising symmetrically disubstituted
O,O0-dialkyldithiophosphate ligands. The principally dif-
ferent coordination modes of O,O0-dipropyldithiophos-
phate and O,O0-di-iso-butyldithiophosphate ligands (i.e.,
S,S0-bidentate chelating and S-unidentately coordinated,
respectively) have been established for these two chemically
related compounds, which are characterised by either a dis-
torted octahedral (1) or a trigonally bipyramidal (2) molec-
ular structures. Spinning sideband patterns, which were
observed in 31P MAS NMR spectra of both compounds
1 and 2, display either mainly rhombic or profound axially
symmetric characters of the 31P chemical shift tensors for
bidentate chelating and unidentately coordinated dithio-
phosphate ligands, respectively. To characterise quantita-
tively the phosphorus sites in both species of
dithiophosphate ligands, 31P chemical shift anisotropy
parameters (daniso and g) were successfully calculated from
spinning sideband manifolds. Correlations between
resolved molecular structures of both tetraphenylanti-
mony(V) complexes and 31P NMR data are also discussed.
[Sb(C H ) {S P(O-i-C H ) }] (2): , 138.4, 135.3, 133.1,
*
6
5 4
2
4
9 2
130.8, 130.1, 129.7 (C6H5–); 73.1, 71.2 (1:1, –OCH2–); 30.1,
29.5 (1:1, –CH@); 20.6, 20.1, 19.6, 17.9 (1:1:1:1, –CH3).
(
*
13C resonance lines assigned to „C–Sb are too broad
to determine the corresponding chemical shifts.) Cf. data
for the original K{S2P(O-i-C4H9)2}: (1:1:2) – 75.1, 74.2,
73.5, 73.2, 72.9 (–OCH2–); 29.9, 29.8, 29.7 (–CH@); 21.1,
21.0, 20.9, 20.8, 20.7, 20.6, 20.4, 20.3, 20.2, 20.1 (–CH3).
For X-ray diffraction studies, suitable single crystals of
(O,O0-dipropyldithiophosphato-S,S0)tetraphenylantimony
(V), [Sb(C6H5)4{S2P(OC3H7)2}] (1) and (O,O0-di-iso-buty-
ldithiophosphato-S)tetraphenylantimony(V), [Sb(C6H5)4-
{S2P(O-i-C4H9)2}] (2) were prepared using recrystallisation
of precipitated complexes from benzene–heptane (1:1) solu-
tions at room temperature. Both complexes 1 and 2 have
been isolated as prismatic transparent and colourless
crystals. Yield (1) 71%. Anal. Calc. for C30H34O2PS2Sb
(Mr = 643.41): C, 55.99; H, 5.29; Sb, 18.97. Found: C,
55.81; H, 4.18; Sb, 18.88%. Yield (2), 66%. Anal. Calc.
for C32H38O2PS2Sb (Mr = 671.46): C, 57.23; H, 5.66; Sb,
18.18. Found: C, 57.15; H, 5.71; Sb, 18.13%.
2.3. Physical measurements
2. Experimental
2.3.1. 13C and 31P CP/MAS NMR spectroscopy
Solid state 13C and 31P magic-angle-spinning (MAS)
NMR spectra were recorded on a Varian/Chemagnetics
InfinityPlus CMX-360 (B0 = 8.46 T) spectrometer operat-
ing in the pulsed Fourier transform mode, using cross-
polarisation (CP) from the protons together with proton
decoupling [5]. The 13C/31P operating frequencies were
90.52/145.73 MHz, respectively. The proton p/2 pulse
durations were 5.2/5.2 ls, CP mixing times were 1.5/
4.5 ms and the nutation frequencies of protons during
decoupling xnut/2p = 43/47 kHz. For each sample, 3600–
7500/380–2000 transients, spaced by relaxation delays of
2.5/3.0 s, were accumulated. Polycrystalline samples (ca.
350 mg) were packed in zirconium dioxide standard double
bearing 7.5 mm rotors. The spinning frequencies for stud-
ied samples ranged from 4200 to 4500/3000 to 4000 Hz
and were stabilised to 2 Hz using a built-in stabilisation
device. All 13C and 31P NMR spectra were recorded at
room temperature (ca. 295 K).
2.1. Materials
Two potassium salts of symmetrically disubstituted
O,O0-dialkyldithiophosphoric acids, which constitute the
major components of the commercial collectors Danaflo-
ats, were provided to us by ‘CHEMINOVA AGRO A/S’:
O,O0-di-n-propyldithiophosphate
– Danafloat-133 K.
O,O0-di-i-butyldithiophosphate
– Danafloat-245 K.
–
K{S2P(OC3H7)2}
–
K{S2P(O-i-C4H9)2}
2.2. Synthesis of polycrystalline complexes
O,O0-Dialkyldithiophosphate tetraphenylantimony(V)
complexes, [Sb(C6H5)4{S2P(OR)2}] (1) (R = C3H7) and
(2) (R = i-C4H9), were prepared by mixing aqueous
solutions of [Sb(C6H5)4]Cl and an excess (ꢀ10%) of
the corresponding potassium dialkyldithiophosphate,
K{S2P(OR)2}. The resulting yellowish-white precipitates
were collected by filtration, washed with water, dried natu-
13C Isotropic chemical shifts (in the deshielding,
d-scale) were externally referenced to the least shielded
resonance of solid adamantane at 38.56 ppm relative to
tetramethylsilane [6]. Chemical shifts and integrated

M.A. Ivanov et al. / Inorganica Chimica Acta 360 (2007) 2897–2904
2899
intensity ratios for overlapping signals in the 13C NMR
spectra were additionally refined by fragment-by-fragment
simulations taking into account both line positions and
line widths, as well as the Lorentzian and Gaussian con-
tributions to the line shapes. All 31P chemical shift data
are given with respect to 85.5% H3PO4 [7] (here, 0 ppm,
externally referenced), which was mounted in a short
1 mm glass tube and placed in a 7.5 mm rotor to avoid
errors due to differences in the magnetic susceptibility.
Drifts in the 13C/31P frequencies (B0-drift) were 0.051/
0.11 Hz hꢁ1, respectively. The homogeneity of the mag-
netic field was monitored by measuring the width of the
which is needed for more accurate estimation of CSA
parameters, spectra were also recorded at low spinning fre-
quencies (1–3 kHz).
2.3.2. Crystal structure determination
Suitable single crystals of
1 and 2 [Sb(C6H5)4-
{S2P(OR)2}] (R = C3H7 and i-C4H9) were selected and
Table 2
Selected
˚
(A)
bond
lengths
and
bond
angles
(ꢁ)
for
[Sb(C6H5)4{S2P(OC3H7)2}] (1)
Bond lengths
reference
signal
of
crystalline
adamantane
at
d(13C) = 38.56 ppm, which was 2.6 Hz.
Sb–C(11)
Sb–C(21)
Sb–C(31)
Sb–C(41)
Sb–S(1)
Sb–S(2)
S(1)–P
S(2)–P
P–O(1)
2.126(1)
C(14)–C(15)
C(15)–C(16)
C(21)–C(22)
C(21)–C(26)
C(22)–C(23)
C(23)–C(24)
C(24)–C(25)
C(25)–C(26)
C(31)–C(32)
C(31)–C(36)
C(32)–C(33)
C(33)–C(34)
C(34)–C(35)
C(35)–C(36)
C(41)–C(42)
C(41)–C(46)
C(42)–C(43)
C(43)–C(44)
C(44)–C(45)
C(45)–C(46)
1.377(2)
1.389(2)
1.394(2)
1.388(2)
1.392(2)
1.382(2)
1.381(2)
1.390(2)
1.396(2)
1.392(2)
1.391(2)
1.375(2)
1.387(2)
1.391(2)
1.398(2)
1.392(2)
1.391(2)
1.378(3)
1.385(2)
1.395(2)
2.123(1)
2.149(1)
2.128(1)
3.0060(4)
3.5571(4)
1.9981(5)
1.9577(5)
1.601(1)
1.602(1)
1.451(2)
1.456(2)
1.496(2)
1.521(2)
1.507(2)
1.491(3)
1.384(2)
1.390(2)
1.397(2)
1.374(3)
The anisotropy, daniso = dzz ꢁ diso, and the asymmetry
parameter of 31P chemical shift tensor (CST),
g = (dyy ꢁ dxx)/(dzz ꢁ diso), were estimated from the deter-
mined ratios between integrated sideband intensities for
each phosphorus site in the NMR spectra recorded at
two different spinning frequencies using a simulation pro-
gram in the Mathematica front end [8]. To increase the
number of spinning sidebands (>10) in 31P NMR spectra,
P–O(2)
O(1)–C(1)
O(2)–C(4)
C(1)–C(2)
C(2)–C(3)
C(4)–C(5)
C(5)–C(6)
C(11)–C(12)
C(11)–C(16)
C(12)–C(13)
C(13)–C(14)
Table 1
Selected crystal data for [Sb(C6H5)4{S2P(OC3H7)2}] (1) and
[Sb(C6H5)4{S2P(O-i-C4H9)2}] (2)
Empirical formula
Formula weight
Crystal system
Space group
C
30H34O2PS2Sb
C32H38O2PS2Sb
671.46
triclinic
643.41
monoclinic
P21/n
ꢀ
P1
Crystal shape
Crystal size (mm)
Unit cell dimensions
prism
0.26 · 0.25 · 0.18
prism
0.32 · 0.26 · 0.18
Bond angles
S(1)–Sb–S(2)
P–S(1)–Sb
P–S(2)–Sb
S(1)–P–S(2)
O(1)–P–S(1)
O(1)–P–S(2)
O(2)–P–S(1)
O(2)–P–S(2)
60.943(9)
99.08(2)
83.56(2)
116.39(2)
109.70(4)
111.82(4)
109.78(4)
112.44(5)
94.59(6)
118.97(9)
117.6(1)
108.9(1)
112.2(1)
110.0(1)
113.7(2)
79.80(4)
80.87(4)
172.27(4)
87.85(4)
71.04(4)
70.00(3)
111.41(4)
148.79(4)
141.04(5)
96.88(5)
106.10(5)
97.83(5)
106.62(5)
99.80(5)
117.6(1)
121.2(1)
C(11)–C(12)–C(13)
C(12)–C(11)–C(16)
C(13)–C(14)–C(15)
C(14)–C(13)–C(12)
C(14)–C(15)–C(16)
C(15)–C(16)–C(11)
C(22)–C(21)–Sb
118.9(2)
120.9(1)
120.2(2)
120.5(2)
120.5(2)
119.0(1)
121.8(1)
117.7(1)
120.0(1)
119.2(1)
120.0(1)
119.6(2)
120.8(2)
120.3(1)
120.6(1)
120.5(1)
120.2(1)
119.8(1)
120.6(2)
120.1(2)
120.4(1)
118.9(1)
118.0(1)
122.6(1)
120.2(1)
119.8(2)
120.1(1)
120.6(2)
119.9(2)
119.4(1)
˚
a (A)
11.0359(3)
12.4279(4)
21.6507(7)
90.000
95.604(1)
90.000
2955.3(2)
4
1.446
9.2220(5)
9.4371(5)
19.004(1)
83.817(1)
77.966(1)
87.759(1)
1607.9(2)
2
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
C(26)–C(21)–Sb
3
˚
V (A )
O(1)–P–O(2)
C(1)–O(1)–P
C(4)–O(2)–P
C(21)–C(26)–C(25)
C(23)–C(22)–C(21)
C(24)–C(23)–C(22)
C(24)–C(25)–C(26)
C(25)–C(24)–C(23)
C(26)–C(21)–C(22)
C(32)–C(31)–Sb
Z
Dcalc (g cmꢁ3
)
1.387
Temperature (K)
l (Mo Ka) (mmꢁ1
h Range
173(1)
1.154
173(1)
1.064
O(1)–C(1)–C(2)
C(1)–C(2)–C(3)
O(2)–C(4)–C(5)
C(4)–C(5)–C(6)
C(11)–Sb–S(1)
C(21)–Sb–S(1)
C(31)–Sb–S(1)
C(41)–Sb–S(1)
C(11)–Sb–S(2)
C(21)–Sb–S(2)
C(31)–Sb–S(2)
C(41)–Sb–S(2)
C(11)–Sb–C(21)
C(11)–Sb–C(31)
C(11)–Sb–C(41)
C(21)–Sb–C(31)
C(21)–Sb–C(41)
C(31)–Sb–C(41)
C(12)–C(11)–Sb
C(16)–C(11)–Sb
)
2.47–31.53
ꢁ15 ! 16,
ꢁ18 ! 18,
ꢁ31 ! 29
1312
2.71–31.52
ꢁ13 ! 13,
ꢁ13 ! 13,
ꢁ27 ! 27
688
Range of h, k and l
C(36)–C(31)–Sb
C(33)–C(32)–C(31)
C(33)–C(34)–C(35)
C(34)–C(33)–C(32)
C(34)–C(35)–C(36)
C(35)–C(36)–C(31)
C(36)–C(31)–C(32)
C(42)–C(41)–Sb
F(000)
Rint
0.0374
8150
0.0293
9412
Number of
observations
Criterion of
significance
Number of parameters 327
Weighting scheme
I > 2r(I)
I > 2r(I)
347
C(46)–C(41)–Sb
w ¼ 1=½s2ðF 2oÞþ
w ¼ 1=½s2ðF 2oÞþ
C(41)–C(46)–C(45)
C(43)–C(42)–C(41)
C(43)–C(44)–C(45)
C(44)–C(43)–C(42)
C(44)–C(45)–C(46)
C(46)–C(41)–C(42)
2
2
ð0:0307PÞ þ 1:7993Pꢂ, ð0:0446PÞ þ 0:9291Pꢂ,
where
where
P ¼ ðF 2o þ 2F 2c Þ=3
P ¼ ðF 2o þ 2F 2cÞ=3
S (goodness-of-fit)
1.087
1.069
R1, wR2 (F2 > 2r(F2))
0.0309, 0.0708
1.348, ꢁ0.544
0.0339, 0.0835
1.799, ꢁ0.674
3
˚
Dqmax, Dqmin (e/A )

2900
M.A. Ivanov et al. / Inorganica Chimica Acta 360 (2007) 2897–2904
mounted on glass fibres with epoxy glue. Experimental
intensity data were collected at T = 173(1) K for both com-
pounds 1 and 2 on a BRUKER SMART 1000 CCD dif-
fractometer with graphite monochromated Mo Ka
radiation (k = 0.71073 A) [9] (crystal-detector distance
45 mm). For compounds 1/2, data were collected in series
of 906/606 frames at u = 0ꢁ, 90ꢁ and 180ꢁ/0ꢁ, 90ꢁ, 180ꢁ
and 270ꢁ; x scan with an increment of 0.2ꢁ/0.3ꢁ and an
exposure time of 20 s/20 s per frame was used. Intensity
data were corrected for absorption using the indices of
equivalent reflections. The unit cell dimensions, additional
crystallographic data and refinement results for the com-
plexes are given in Table 1.
˚
Table 3
The structures were solved using direct methods and
refined by least-squares calculation in anisotropic approxi-
mation for non-hydrogen atoms. Hydrogen atoms were
added at ideal positions and refined using a riding model.
Data collection and editing, as well as refinement of unit
cell parameters, was performed with the SMART and SAINT-
Plus program packages [9]. Structure solution and refine-
ment were performed with the SHELXTL/PC program pack-
ages [10]. Selected bond lengths and angles are listed in
Tables 2 and 3. Complete crystallographic details are
included in the Supporting Information.
˚
Selected bond lengths (A) and bond angles (ꢁ) for [Sb(C6H5)4{S2P(O-i-
C4H9)2}] (2)
Bond lengths
Sb–C(11)
Sb–C(21)
Sb–C(31)
Sb–C(41)
Sb–S(1)
S(1)–P
S(2)–P
P–O(1)
P–O(2)
O(1)–C(1)
O(2)–C(5)
C(1)–C(2)
C(2)–C(3)
C(2)–C(4)
C(5)–C(6)
C(6)–C(7)
C(6)–C(8)
C(11)–C(12)
C(11)–C(16)
C(12)–C(13)
C(13)–C(14)
2.147(1)
2.114(1)
2.104(1)
2.115(1)
2.9092(4)
2.0018(6)
1.9450(6)
1.606(1)
1.593(2)
1.473(2)
1.434(3)
1.497(3)
1.532(3)
1.470(4)
1.477(4)
1.494(4)
1.531(4)
1.394(2)
1.389(2)
1.390(2)
1.383(3)
C(14)–C(15)
C(15)–C(16)
C(21)–C(22)
C(21)–C(26)
C(22)–C(23)
C(23)–C(24)
C(24)–C(25)
C(25)–C(26)
C(31)–C(32)
C(31)–C(36)
C(32)–C(33)
C(33)–C(34)
C(34)–C(35)
C(35)–C(36)
C(41)–C(42)
C(41)–C(46)
C(42)–C(43)
C(43)–C(44)
C(44)–C(45)
C(45)–C(46)
Sbꢃ ꢃ ꢃO(1)
1.369(3)
1.400(2)
1.384(2)
1.391(2)
1.393(3)
1.377(3)
1.383(3)
1.394(3)
1.383(2)
1.392(2)
1.395(2)
1.386(3)
1.372(3)
1.389(2)
1.386(2)
1.393(2)
1.390(2)
1.371(3)
1.381(3)
1.395(2)
3.641(1)
3. Results and discussion
3.1. Heteronuclear (13C, 31P) CP/MAS NMR data
Experimental 13C CP/MAS NMR spectra of polycrys-
talline
O,O0-dialkyldithiophosphate
tetraphenylanti-
mony(V) complexes are presented in Fig. 1. There are
two expected groups of 13C resonance lines from (i) alkyl
substituents at the oxygen atoms of Dtph ligands and (ii)
@C@ and @CH– groups of four aromatic C6H5-rings in
Bond angles
P–S(1)–Sb
S(2)–P–S(1)
109.92(2)
C(11)–C(16)–C(15)
C(16)–C(11)–C(12)
C(22)–C(21)–Sb
119.8(2)
117.62(3)
105.84(5)
112.82(5)
108.50(6)
106.95(6)
104.26(9)
121.7(1)
109.2(2)
108.4(2)
114.2(2)
111.7(2)
121.7(1)
110.5(2)
110.5(3)
109.5(2)
111.1(2)
176.23(4)
82.42(4)
78.45(4)
86.79(4)
99.01(6)
97.80(5)
95.35(5)
115.24(5)
121.90(5)
118.00(6)
117.4(1)
123.5(1)
120.6(2)
119.9(2)
120.0(2)
120.7(2)
119.0(1)
120.1(1)
118.9(1)
119.0(2)
120.6(2)
120.2(2)
120.2(2)
119.0(2)
121.0(1)
118.2(1)
121.3(1)
119.2(2)
120.2(2)
120.2(2)
120.3(2)
119.6(2)
120.5(1)
122.1(1)
117.0(1)
119.0(2)
120.6(2)
120.4(2)
120.0(2)
119.0(2)
120.8(1)
92.96(5)
126.0(1)
50.83(2)
132.94(4)
68.73(4)
128.93(4)
60.71(4)
O(1)–P–S(1)
O(1)–P–S(2)
O(2)–P–S(1)
O(2)–P–S(2)
O(1)–P–O(2)
C(26)–C(21)–Sb
C(21)–C(22)–C(23)
C(24)–C(23)–C(22)
C(23)–C(24)–C(25)
C(24)–C(25)–C(26)
C(21)–C(26)–C(25)
C(22)–C(21)–C(26)
C(32)–C(31)–Sb
C(1)–O(1)–P
O(1)–C(1)–C(2)
C(1)–C(2)–C(3)
C(1)–C(2)–C(4)
C(4)–C(2)–C(3)
C(5)–O(2)–P
C(36)–C(31)–Sb
C(31)–C(32)–C(33)
C(34)–C(33)–C(32)
C(35)–C(34)–C(33)
C(34)–C(35)–C(36)
C(35)–C(36)–C(31)
C(32)–C(31)–C(36)
C(42)–C(41)–Sb
O(2)–C(5)–C(6)
C(5)–C(6)–C(7)
C(5)–C(6)–C(8)
C(7)–C(6)–C(8)
C(11)–Sb–S(1)
C(21)–Sb–S(1)
C(31)–Sb–S(1)
C(41)–Sb–S(1)
C(11)–Sb–C(21)
C(11)–Sb–C(31)
C(11)–Sb–C(41)
C(21)–Sb–C(31)
C(21)–Sb–C(41)
C(31)–Sb–C(41)
C(12)–C(11)–Sb
C(16)–C(11)–Sb
C(13)–C(12)–C(11)
C(14)–C(13)–C(12)
C(15)–C(14)–C(13)
C(14)–C(15)–C(16)
C(46)–C(41)–Sb
C(41)–C(42)–C(43)
C(44)–C(43)–C(42)
C(43)–C(44)–C(45)
C(44)–C(45)–C(46)
C(41)–C(46)–C(45)
C(42)–C(41)–C(46)
P–O(1)ꢃ ꢃ ꢃSb
C(1)–O(1)ꢃ ꢃ ꢃSb
S(1)–Sbꢃ ꢃ ꢃO(1)
13
Fig. 1. 90.52 MHz C CP/MAS NMR spectra of polycrystalline O,O0-
C(11)–Sbꢃ ꢃ ꢃO(1)
C(21)–Sbꢃ ꢃ ꢃO(1)
C(31)–Sbꢃ ꢃ ꢃO(1)
C(41)–Sbꢃ ꢃ ꢃO(1)
dipropyldithiophosphate- (a) and O,O0-di-iso-butyldithiophosphate- (b)
tetraphenylantimony(V) complexes. The MAS frequencies were 4.2 in (a)
and 4.5 kHz in (b). The number of transients was 7500 and 3600 in (a) and
(b), respectively. (The sidebands are denoted by ‘s’.)

M.A. Ivanov et al. / Inorganica Chimica Acta 360 (2007) 2897–2904
2901
31
Fig. 2. 145.73 MHz P CP/MAS NMR spectra of polycrystalline O,O0-dialkyldithiophosphate tetraphenylantimony(V) complexes: [Sb(C6H5)4-
{S2P(OC3H7)2}] (a) and (a0); [Sb(C6H5)4{S2P(O-i-C4H9)2}] (b) and (b0). (The central bands are denoted by asterisks.) The MAS frequencies were 1.0 and
3.0 kHz in (a), (b) and (a0), (b0), respectively. The number of transients was 380 in (a), 128 in (a0), 1680 in (b) and 2000 in (b0).
Table 4
the discussed spectra of both complexes 1 and 2. Pairs of
31Pa NMR chemical shift tensor parameters for O,O0-dialkyldithiophos-
highly shielded 13C resonance lines, which appear between
phate tetraphenylantimony(V) complexes
9.5 and 67 ppm (compound 1) and 17.5 and 73 ppm (2), are
Compound
31P
assigned to –OCH2–, –CH2–, –CH@ and –CH3 groups in
Dtph ligands. They have almost equal integral intensities
that suggests a structural inequivalence in the neighbouring
chains of alkyl substituents at the oxygen atoms. In con-
trast, aromatic C6H5– rings have poorly shielded 13C sites
with chemical shift values laying within the ranges of
128.6–149.4 and 129.7–138.4 ppm for compounds 1 and
2, respectively. (The most deshielded resonance line at
ꢀ150 ppm assigned to the carbon atom directly bound to
the antimony atom in 1 is not observed in 2 because of a
severe line broadening.) This assignment is in accord with
previously reported 13C chemical shifts for carbon sites in
phenyl groups of polycrystalline heteroleptic N,N-dial-
kyldithocarbamate tetraphenylantimony(V) complexes
[3,4].
diso
(ppm)
daniso
gb
(ppm)b
(1) [Sb(C6H5)4{S2P(OC3H7)2}]
107.6
ꢁ84.1 0.4 0.98 0.01
ꢁ117.0 0.7 0.12 0.03
(2) [Sb(C6H5)4{S2P(O-i-C4H9)2}] 106.8
(1a) K{S2P(OC3H7)2} [18]
114.7
114.5
(1:1)
ꢁ106
3
4
0.1 0.1
0.23 0.14
ꢁ109
(2a) K{S2P(O-i-C4H9)2} [18]
110.9
ꢁ123.0 2.0
0.0 0.1
a
Relative to 85.5% H3PO4, deshielding scale.
aniso = dzz ꢁ diso; g = (dyy ꢁ dxx)/(dzz ꢁ diso).
b
d
bonds of dithiophosphate groups with the antimony atom
is the origin of the observed additional shielding.
Fig. 2 displays 31P CP/MAS NMR spectra of both poly-
crystalline compounds 1 (Figs. 2a and 2a0) and 2 (Figs. 2b
and 2b0) obtained at two different spinning frequencies (1
and 3 kHz). Isotropic chemical shifts for phosphorus sites
in these compounds can be read from the positions of the
centrebands (marked by asterisks in Fig. 2), which are
flanked by the spinning sidebands. In each 31P MAS
NMR spectrum, only one centreband resonance line was
observed that suggests unique structural positions of the
phosphorus atoms in each of the two O,O0-dialkyldithio-
phosphate tetraphenylantimony(V) complexes. A compar-
ative analysis of isotropic 31P chemical shift values for
the above heteroleptic antimony(V) complexes and the ini-
tial potassium dialkyldithiophosphates (see Table 4) reveals
more shielded phosphorus sites (smaller values in the desh-
ielding d-scale) in the former case. This result corresponds
to our previous 31P NMR studies performed for O,O0-dial-
kyldithiophosphate complexes of various bivalent transi-
tion metals [11–20]. Therefore, the formation of covalent
In spite of the close 31P isotropic chemical shift values
(see Table 4), compounds 1 and 2 have remarkably dif-
ferent shapes of the spinning sideband patterns in their
31P CP/MAS NMR spectra (Fig. 2) that points out at
large differences in 31P chemical shift anisotropies
(CSA) of phosphorus sites in these molecular systems.
These kinds of MAS 31P NMR spectral pattern reflect,
undoubtedly, either mainly rhombic or almost axially
symmetric characters of the 31P chemical shift tensor
(CST) of phosphorus sites in the cases 1 and 2, respec-
tively. Moreover, our previous 31P MAS NMR studies
of O,O0-dialkyldithiophosphate zinc(II) [11,12,18], nicke-
l(II) [16,18], cadmium(II) [13–15,20] and lead(II) [17,19]
complexes allowed us to conclude with confidence, that
principally different coordination modes of Dtph groups
in the complexes 1 and 2 are in the basis of these differ-
ences in 31P CSTs.
To confirm the validity of this conclusion based on 31P
CP/MAS NMR data, the molecular structures of the

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M.A. Ivanov et al. / Inorganica Chimica Acta 360 (2007) 2897–2904
Fig. 3. Molecular structures of complexes 1, [Sb(C6H5)4{S2P(OC3H7)2}] (a) and 2, [Sb(C6H5)4{S2P(O-i-C4H9)2}] (b).
˚
complexes 1 and 2 were resolved by the direct method, the
single-crystal X-ray diffraction data analysis.
Dtph group: Sb–S(1) 2.9092 A define two axial positions.
In the antimony distorted trigonal bipyramidal polyhe-
˚
dron, the central atom is 0.2706 A shifted out of the mean
3.2. Structural description of [Sb(C6H5)4{S2P(OC3H7)2}]
(1) and [Sb(C6H5)4{S2P(O-i-C4H9)2}] (2)
[S3] plane towards the axial carbon atom C(11). The C(11)–
Sb–S(1) angle is equal to 176.23ꢁ that is close to the corre-
sponding value in the ideal trigonal bipyramid (TBP)
ꢁ180ꢁ. However, the observed deviation of this angle from
180ꢁ indicates some contribution of a tetragonal pyramid
(TP) to the geometry of the antimony coordination polyhe-
dron [SbC4S]. To characterise the geometry of discussed
coordination polyhedron quantitatively, the s-descriptor
was used in our analysis. This s-descriptor has been sug-
gested by Addison et al. [21] as a convenient parameter
and defined using the following equation s = (a ꢁ b)/60
(in our case, a and b are the two largest L–Sb–L angles,
a > b). In an ideal TP (C4v), s = 0 since a = b. In a regular
TBP (C3v), the axial L–Sb–L angle (a) is equal to 180ꢁ,
while the equatorial angle (b) is 120ꢁ giving rise to s = 1.
A polyhedron manifold with contributions from 100%
TBP to 100% TP corresponds to s values falling within
the range 1–0. In molecule 2, the two largest L–Sb–L
angles: C(11)–Sb–S(1) and C(21)–Sb–C(41) are equal to
176.23ꢁ and 121.90ꢁ, respectively (see Table 3). Therefore,
s = 0.9055, which point to 90.55% and 9.45% contributions
of TBP and TP, respectively, to a geometry of the anti-
mony coordination polyhedron.
The molecular structures resolved for the heteroleptic
tetraphenylantimony(V) complexes 1, [Sb(C6H5)4{S2-
P(OC3H7)2}] and 2, [Sb(C6H5)4{S2P(O-i-C4H9)2}] are
shown in Fig. 3; selected bond lengths and angles are given
in Tables 2 and 3. There are four and two discrete structur-
ally equivalent molecules in the unit cells of complexes 1
and 2, respectively. In each discussed compound, the cen-
tral antimony atom links four phenyl planar rings and
one O,O0-dialkyldithiophosphate ligand. Nevertheless,
different types of geometry have been established for the
aforementioned molecules. The distorted octahedral chro-
mophore [SbC4S2] and the trigonal bipyramidal one
[SbC4S] were discovered in the molecular structures 1 and
2, respectively. These unexpected structural distinctions
between chemically related compounds are defined by the
principally different coordination modes of O,O0-
dipropyldithiophosphate and O,O0-di-iso-butyldithiophos-
phate ligands in their molecular structures (i.e., a bidentate
chelating and an unidentate coordination, respectively).
Let us examine the molecular structures of compounds 1
and 2 in detail. There are four planar phenyl rings and
S-unidentately coordinated O,O0-di-iso-butyldithiophos-
phate ligand in the inner coordination sphere of complex
2 (Fig. 3b). These exhibit a distorted trigonal bipyramidal
neighbouring environment of the antimony atom (with
the coordination number equal to 5). Three phenyl rings
forming the short chemical bonds Sb–C(21, 31, 41)
In complex 1, whose structure is shown in Fig. 3a, the
central antimony atom is bound with four carbon atoms
of phenyl groups and with both sulphur atoms of the Dtph
group, defining the six-fold coordination and exhibiting a
distorted octahedral molecular structure. Hence, in con-
trary to complex 2, O,O0-dipropyldithiophosphate ligand
displays a bidentate coordination mode in the molecular
structure of 1. The central metal atom links three phenyl
groups by short chemical bonds Sb–C(11, 21, 41) (2.123–
˚
(2.104–2.115 A, see Table 2) are in the equatorial plane
of the discussed trigonal bipyramid, while the fourth, less
˚
˚
strongly bound, phenyl ring: Sb–C(11) 2.147 A and the
2.128 A, see Table 3) and by one, weakly bound, sulphur

M.A. Ivanov et al. / Inorganica Chimica Acta 360 (2007) 2897–2904
2903
Fig. 4. v2 statistics as a function of the 31P CSA parameters daniso and g. Graphs for [Sb(C6H5)4{S2P(OC3H7)2}] (a) and [Sb(C6H5)4{S2P(O-i-C4H9)2}] (b)
are presented. The 68.3% joint confidence limit (solid) and 95.4% joint confidence limit (dashed) for the two CSA parameters are shown. In each case (a)
and (b) simulations were performed for one P-site but at two different spinning frequencies: 2 kHz (thick lines) and 3 kHz (thin lines).
(d22 is close to d11, daniso < 0),1 while for small S–P–S angles
(specific for terminal chelating Dtph ligands) the 31P CST is
oblate (d22 is close to d33, daniso > 0) [18,19].
However, newly prepared here heteroleptic antimony(V)
complex 2 comprises another type of binding, i.e. an uniden-
tate coordination of the O,O0-di-iso-butyldithiophosphate
ligand to the central atom. This type of binding is character-
ised by a large S–P–S angle, which is close to 120ꢁ as in ionic
Dtph compounds with an essential contribution of the dou-
ble bond character in one of the two P–S bonds.
˚
atom Sb–S(2) 3.5571 A in the equatorial plane of the dis-
torted octahedron. The fourth, less strongly bound, phenyl
˚
ring: Sb–C(31) 2.149 A and the other sulphur atom: Sb–
˚
S(1) 3.0060 A are in the axial positions. The axial S(1)
and C(31) atoms have an S–Sb–C angle 172.27ꢁ that is
noticeably deviated from the ideal value of 180ꢁ.
The bidentate coordination mode of the O,O0-dip-
ropyldithiophosphate ligand leads to formation of a four-
membered chelate ring [SbS2P]. This ring is characterised
by an almost planar geometry that is supported by values
of P–S–S–Sb and S–Sb–P–S torsion angles (178.2ꢁ and
178.3ꢁ, respectively). The dithiophosphate group is essen-
tially anisobidentate: one of the sulphur atoms forms a
To characterise quantitatively phosphorus sites in both
the bidentate chelating and the unidentately coordinated
Dtph ligands of the heteroleptic tetraphenylantimony(V)
˚
rather strong chemical bond – S(1)–Sb 3.0060 A, while
complexes 1 and 2, both 31P isotropic chemical shifts, diso
,
the other one is weakly bound to the central Sb atom –
S(2)–Sb 3.5571 A.
and the 31P chemical shift anisotropy (CSA) parameters
were implemented. To evaluate 31P CSAs, relative intensi-
ties of sidebands in spinning sideband manifolds (see
Fig. 2) were incorporated in the Mathematica program
developed by Levitt and co-workers [8]. This program
calculates v2-statistics as a function of the two 31P
CSA parameters: the chemical shift anisotropy, specified
as daniso = dzz ꢁ diso, and the asymmetry parameter of the
chemical shift tensor, g = (dyy ꢁ dxx)/(dzz ꢁ diso). The glo-
bal minimum of this statistics, v2min, gives values for the
two CSA parameters, daniso and g, while the joint confi-
dence limit is the measure of errors for these parameters
[8]. Fig. 4 shows joint confidence limits for daniso and g,
while 31P CSA data given in Table 4 correspond to the min-
ima on v2-plots [8]. (It is necessary to note that the zero
asymmetry parameter, g = 0, corresponds to an axially
symmetric CST, while an increase of the g-value from 0
to 1 reflects a rise in the rhombicity of the CST.) In spite
of close 31P isotropic chemical shifts, diso, for P-sites in
Dtph ligands of complexes 1 and 2, two 31P CSTs are
˚
Hence, the principally different coordination modes
of O,O0-dipropyl- and O,O0-di-iso-butyldithiophosphate
ligands to the central antimony atom (i.e., a bidentate che-
lating and an unidentately coordinated, respectively) are in
the basis of all main structural distinctions between these
chemically related compounds 1 and 2.
3.3. Correlations between 31P chemical shift anisotropy and
S–P–S angle
Previously, we reported on crystalline dialkyldithio-
phosphate nickel(II), zinc(II), cadmium(II) and lead(II)
complexes of mononuclear, binuclear and polynuclear
molecular structures [11–20]. Dtph groups in these com-
pounds have either terminal chelating or/and bidentate
bridging or/and combined (tridentate bridging) structural
functions. Using X-ray diffraction, 31P NMR data and
ab initio quantum mechanical calculations on the above
systems, we have found empirical correlations between
the S–P–S angle and the principal components of the 31P
chemical shift tensor (CST): for large S–P–S angles (char-
acteristic for bridging Dtph ligands) the tensor is prolate
1
Defined as d11 > d22 > d33; daniso = dzz ꢁ diso; g = (dyy ꢁ dxx)/(dzz
ꢁ
d
d
iso); jdzz ꢁ disoj > jdxx ꢁ disoj > jdyy ꢁ disoj, i.e., dyy = d22, dzz = d11 or
33, and dxx = d33 or d11
.

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M.A. Ivanov et al. / Inorganica Chimica Acta 360 (2007) 2897–2904
remarkably different (see Fig. 4 and Table 4). As expected
from the general shapes of the spinning sideband patterns
in 31P CP/MAS NMR spectra of 1 and 2, one of 31P
CST (for 1) displays a profoundly rhombic character:
g = 0.98 and daniso = ꢁ84.1 ppm, while the other one (for
2) is an almost axially symmetric prolate tensor: g = 0.12
and daniso = ꢁ117.0 ppm (see also Fig. 4 and Table 4). Fur-
thermore, previously, we have reported on the sign correla-
tion of daniso with the S–P–S angle values [18]. Moreover, in
a range of negative daniso values, it was shown that the
higher jdanisoj values correspond to the larger S–P–S angles.
In our cases 1 and 2, jdanisoj = 84.1 ppm correlates with the
smaller S–P–S angle 116.39ꢁ (for 1) and jdanisoj =
117.0 ppm corresponds to the larger S–P–S angle 117.62ꢁ
(for 2), that is in a good agreement with our previous 31P
MAS NMR studies [11–20].
Appendix A. Supplementary material
CCDC 607257 and 607258 contain the supplementary
crystallographic data (excluding structure factors) for this
paper. These data can be obtained free of charge via
http://www.ccdc.cam.ac.uk/conts/retrieving.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. Supplementary
data associated with this article can be found, in the online
version, at doi:10.1016/j.ica.2007.02.044.
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4. Conclusions
Crystalline heteroleptic O,O0-dipropyl- (1) and O,O0-di-
iso-butyldithiophosphate (2) tetraphenylantimony(V) com-
plexes were studied by means of heteronuclear 13C, 31P CP/
MAS NMR spectroscopy and single-crystal X-ray diffrac-
tion. Discrete molecules of prepared complexes 1 and 2
are characterised by a distorted octahedral and a trigonal
bipyramidal geometries, respectively. These unexpected
structural differences between similar compounds are gov-
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and O,O0-di-iso-butyldithiophosphate ligands to antimony
atoms in the molecular structures of 1 and 2 (i.e. S,S0-
bidentate chelating and S-unidentately coordinated,
respectively). The 31P chemical shift anisotropy parame-
ters, daniso and g, are remarkably different for phosphorus
sites in these two species of Dtph ligands. The 31P CST is
mainly rhombic (g = 0.98) in 1, while it is almost axially
symmetric prolate tensor in 2 (g = 0.12). The 31P CST data
correlate with differences in S–P–S bond angles in these
molecular systems: 116.39ꢁ and 117.62ꢁ in 1 and 2, respec-
tively, in accord with previously reported ab initio quan-
tum mechanical calculations for a model [(CH3O)2PS2]ꢁ
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Acknowledgments
This work has been financially supported by Agricola
Research Centre at Lulea University of Technology and
˚
granted by the Russian Foundation of Fundamental Re-
search and the Far East Division of the Russian Acad-
emy of Sciences (project No. 06-0396009). We are
grateful to ‘CHEMINOVA AGRO A/S’ for dithiophos-
phate chemicals, which were kindly supplied for this
study. The CMX-360 spectrometer was purchased with
a grant from the Swedish Council for Planning and
Coordination of Research (FRN). We thank the founda-
tion to the memory of J.C. and Seth M. Kempe for a
grant from which a part of the NMR equipment has
been purchased.
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