Reactions and structures in the gallium(III)/indium(III)-N,N- dimethylthioformamide systems

Article abstract of DOI:10.1016/j.ica.2010.09.011

The structure of the N,N-dimethylthioformamide (DMTF) solvated gallium(III) ion has been determined in solution by means of extended X-ray absorption fine structure (EXAFS) spectroscopy. The gallium(III) ion is four-coordinate in tetrahedral fashion with a mean Ga-S bond distance of 2.233(2) in DMTF solution. At the dissolution of indium(III) perchlorate or trifluoromethanesulfonate in DMTF coordinated solvent molecules are partly reduced to sulfide ions, and a tetrameric complex with the composition [In₄S₄(SHN(CH ₃)₂)₁₂]⁴⁺ is formed. The structure of the solid tetrameric complex in the perchlorate salt was solved with single crystal X-ray diffraction. Four indium(III) ions and four sulfide ions form a highly symmetric heterocubane structure where each indium binds three bridging sulfide ions and each sulfide ion binds three indium(III) ions with a mean In-S bond distance of 2.584(1) , and S-In-S angles of 90.3(1)°. Each indium(III) additionally binds three DMTF molecules at significantly longer mean In-S bond distance, 2.703(1) ; the S-In-S angles are in the range 80.3-90.4°. Large angle X-ray scattering data on a DMTF solution of indium(III) trifluoromethanesulfonate show that the same tetrameric species characterized in the solid state is also present in solution, whereas the EXAFS measurements only give information about the In-S bond distances due to the short core hole lifetime.

Full text of DOI:10.1016/j.ica.2010.09.011

Inorganica Chimica Acta 365 (2011) 220–224
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Inorganica Chimica Acta
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Reactions and structures in the gallium(III)/indium(III)-
N,N-dimethylthioformamide systems
1
⇑
Önder Topel , Ingmar Persson , Daniel Lundberg, Ann-Sofi Ullström
Department of Chemistry, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 20 March 2010
Received in revised form 1 September 2010
Accepted 10 September 2010
Available online 17 September 2010
The structure of the N,N-dimethylthioformamide (DMTF) solvated gallium(III) ion has been determined
in solution by means of extended X-ray absorption fine structure (EXAFS) spectroscopy. The gallium(III)
ion is four-coordinate in tetrahedral fashion with a mean Ga–S bond distance of 2.233(2) Å in DMTF solu-
tion. At the dissolution of indium(III) perchlorate or trifluoromethanesulfonate in DMTF coordinated sol-
vent molecules are partly reduced to sulfide ions, and a tetrameric complex with the composition
4+
[In4S4(SHN(CH3)2)12
]
is formed. The structure of the solid tetrameric complex in the perchlorate salt
Keywords:
was solved with single crystal X-ray diffraction. Four indium(III) ions and four sulfide ions form a highly
symmetric heterocubane structure where each indium binds three bridging sulfide ions and each sulfide
ion binds three indium(III) ions with a mean In–S bond distance of 2.584(1) Å, and S–In–S angles of
90.3(1)°. Each indium(III) additionally binds three DMTF molecules at significantly longer mean In–S
bond distance, 2.703(1) Å; the S–In–S angles are in the range 80.3–90.4°. Large angle X-ray scattering
data on a DMTF solution of indium(III) trifluoromethanesulfonate show that the same tetrameric species
characterized in the solid state is also present in solution, whereas the EXAFS measurements only give
information about the In–S bond distances due to the short core hole lifetime.
Gallium(III)
Indium(III)
N,N-dimethylthioformamide (DMTF)
EXAFS
Ó 2010 Elsevier B.V. All rights reserved.
1. Introduction
have been reported so far, and only one, with a Ga4S4 core, has
ordinary electron-pair donor ligands binding to the metal ions.
The number of homoleptic gallium(III) and indium(III) com-
plexes with sulfur donor ligands is limited, and no pure solvate
complexes with monodentate sulfur donor solvents have been re-
ported so far. The homoleptic complexes of gallium(III) and indiu-
m(III) with monodentate sulfur donor ligands are all thiolates, and
have all tetrahedral configuration with mean Ga–S and In–S bond
distances of 2.268 and 2.462 Å, respectively, Tables S1 and S2.
The homoleptic complexes with bidentate sulfur donor ligands as
xanthates, carbamates and dithiophosphates, have octahedral con-
figuration with mean Ga–S and In–S bond distances of 2.437 and
2.603 Å, respectively, Tables S1 and S2. Both gallium(III) and indiu-
m(III) have ability to form metal–sulfur clusters, including tetra-
meric cubane-like M4S4 complexes where the metal additionally
binds one organic group or a soft ligand with distorted configura-
tion around the metal ion. The mean Ga–S and In–S bond distances
in these tetrameric structures are 2.360 and 2.557 Å, respectively,
and with M–S–M and S–M–S angles somewhat below and above
90°, respectively, Tables S1 and S2. No tetrameric heterocubane
structures with octahedral configuration around the metal ion
N,N-dimethylthioformamide is a polar sulfur donor solvent with
high dipole moment, = 4.44 D, and relative permittivity, = 47.5
l
e
[1]. This means that most salts have high solubility and are highly
dissociated in DMTF, an unusual property for a sulfur donor sol-
vent. Another interesting feature of DMTF is the well-ordered bulk
structure due to its hydrogen bonding ability; DMTF forms stron-
ger internal hydrogen bonds than its oxygen analog N,N-dimethyl-
formamide [1]. DMTF is a strong electron-pair donor solvent with
soft Lewis base character, DS = 52 [2], and solvates soft metal ions
such as gold(I) and silver(I) very well, while hard metal ions as so-
dium and potassium are weakly solvated [3]. The structural studies
of DMTF solvated metal ions in solution often show low symmetry
due to electronic effects as shown for silver(I) and mercury(II), and
that in the case of gold(I) and mercury(II) the coordination number
is lower, two and four, respectively, than sterically possible [4,5].
The solvation of the zinc(II), cadmium(II), mercury(II), copper(I),
silver(I), gold(I), iron(II) and iron(III) ions has been studied in DMTF
solution by EXAFS, LAXS, transfer thermodynamics and vibrational
spectroscopy [3–7].
In this study, we report the structure of the DMTF solvated gal-
lium(III) ion in DMTF solution, and the structure of the reaction
product of indium(III) and DMTF, a novel highly symmetric
tetramer with cubane configuration, where the indium(III) ions
octahedrally bind three sulfide ions and three DMTF molecules,
⇑
Corresponding author.
E-mail address: ingmar.persson@kemi.slu.se (I. Persson).
Present address: Department of Chemistry, Faculty of Arts and Sciences, Akdeniz
1
University, 07058 Antalya, Turkey.
0020-1693/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2010.09.011

Ö. Topel et al. / Inorganica Chimica Acta 365 (2011) 220–224
221
Table 1
in both solid state and solution as studied by single crystal X-ray
diffraction, large angle X-ray scattering (LAXS) and extended
X-ray absorption fine structure (EXAFS).
Concentrations (mol dmꢀ3) of N,N-dimethylthioformamide (DMTF) solutions used in
EXAFS or LAXS measurements.
Sample
Concentration
State
Method
(mol dmꢀ3
)
2. Experimental
Ga(CF3SO3)3 in DMTF
In(CF3SO3)3 in DMTF
In(CF3SO3)3 in DMTF
[In4S4(C3H7SH)12](ClO4)4
1.35
1.00
0.763
Solution
Solution
Solution
Yellow powder
EXAFS
EXAFS
LAXS
2.1. Chemicals
EXAFS
N,N-dimethylthioformamide was prepared by reacting phos-
phorus pentasulfide (Merck) and N,N-dimethylformamide (Merck)
in benzene, according to a procedure given by Gutmann et al. [8],
or purchased (Aldrich), and purified by distillation at reduced pres-
sure prior to use.
Anhydrous gallium(III) and indium(III) trifluoromethanesulfo-
nate, M(CF3SO3)3, (M = Ga or In), were prepared by adding an ex-
cess trifluoromethanesulfonic acid, CF3SO3H (Fluka), dropwise to
aqueous slurries of gallium(III) oxide, Ga2O3 (Fluka) and indium(III)
hydroxide, In(OH)3 (Fluka). The slurries were refluxed for 2 h until
a clear solution was obtained. The solutions were filtered, and
water and excess acid were boiled off at ca. 450 K. The anhydrous
gallium(III) and indium(III) trifluoromethanesulfonates were
stored in oven at ca. 450 K to avoid uptake of water.
Indium(III) perchlorate hexahydrate (Alfa) was dissolved in a
minimum amount of dry acetone and then shaken for a few min-
utes. 2,2-Dimethoxypropane (Merck) was added to eliminate the
water of the hydrate [9], and after shaking the mixture for ca.
15 min, six equivalents of DMTF were added to the reaction mix-
ture. As soon as the mixture was shaken a yellowish-white precip-
itate was formed, 1. This mixture was put in freezer where
colorless single crystals suitable for X-ray studies were formed.
The yield of this reaction is almost complete. The melting point
is 439 1 K, but the compound turned brownish at ca. 403 K. The
infrared spectrum of 1 is given in Fig. S1, suspended in oil and
hexachlorobutadiene.
bers with a flow of a gas mixture of nitrogen and argon. The second
monochromator crystal was detuned to 80% of maximum intensity
to reject higher order harmonics. The solutions were kept in cells
with Mylar tape windows and a Teflon spacer 1–2 mm thick. The
solids were ground to a homogeneous mixture with an appropriate
amount of boron nitride (BN) to reach an intensity step of unity,
and placed in a 1.5 mm aluminium frame with Mylar tape win-
dows. Energy calibration of the X-ray absorption spectra was per-
formed by simultaneously recording the edge spectrum of a
metallic gallium or indium foil during the data collection, and
assigning the first
K edge inflection point to 10368.2 and
27940.0 eV, respectively [11]. After energy calibration, 2–3 scans
were averaged for each sample. The EXAFSPAK program package
was used for the data treatment [12]. The EXAFS oscillations were
extracted using standard procedures for pre-edge subtraction,
spline removal and data normalization. Model fitting, including
both single and multiple back-scattering pathways, was performed
with theoretical phase and amplitude functions calculated ab initio
by means of the computer code FEFF7 [13]. The k3-weighted EXAFS
oscillation was analyzed by a non-linear least-squares fitting pro-
cedure of the model parameters.
2.4. Single crystal X-ray diffraction
It was not possible to get any crystals of the DMTF solvated gal-
lium(III) perchlorate or trifluoromethanesulfonate even though
several methods were attempted. However, when the same meth-
od as for indium was applied on gallium, an interesting absorption
in UV–Vis was observed. The color of the solution was purple un-
der a mercury lamp, while it was reddish in daylight.
Data collection were performed on a Bruker SMART platform
equipped with a CCD area detector [14] and a graphite monochro-
mator using Mo Ka radiation, k = 0.7107 Å, at room temperature. A
hemisphere data with 1271 frames was collected using the omega
scan method. The crystal to detector distance was 5.0 cm. The first
50 frames were re-measured at the end of the data collection to
check crystal and instrument stability, no absorption correction
was applied. The structure was solved by direct methods in SHELXTL
[15], and refined using full-matrix least squares on F2. Non-
hydrogen atoms were treated anisotropically. Hydrogen atoms
were calculated in ideal positions riding on their respective carbon
atom.
2.2. Solutions and crystals
The DMTF solutions of gallium(III) and indium(III) trifluoro-
methanesulfonate for EXAFS and LAXS studies were prepared by
dissolving respective anhydrous salt in freshly distilled DMTF;
the composition of these solutions are summarized in Table 1.
The yellow powder obtained by evaporation of the solvent from
the DMTF solution of indium(III) perchlorate was studied by means
of EXAFS.
2.5. Large-Angle X-ray Scattering (LAXS)
A large-angle h–h diffractometer was used to measure the scat-
tering of Mo K
a radiation, k = 0.7107 Å, on the free surface of the
2.3. Extended X-ray absorption fine structure measurements
N,N-dimethylthioformamide solution of indium(III) trifluorometh-
anesulfonate. The solution was contained in a Teflon cup inside a
radiation shield with beryllium windows. The scattered radiation
was monochromatized of by means of a focusing LiF crystal. The
intensity was measured at 450 discrete points in the range
0.5 < h < 65.0° (2h is the scattering angle). A total amount of
100 000 counts was accumulated at each angle and the whole
angular range was scanned twice, corresponding to a statistical
uncertainty of about 0.3%. The divergence of the primary X-ray
beam was limited by 1 or 1/4° slits for different h regions with over-
lapping some part of data for scaling purposes. All data treatment
was carried out by using of the KURVLR program [16] described more
in detail elsewhere [5]. The experimental intensities were normal-
ized to a stoichiometric unit of volume containing one indium
Gallium and indium K edge X-ray absorption data were ob-
tained at beam-line 4-1 at Stanford Synchrotron Radiation Light-
source (SSRL), Stanford, USA. The beam-line was equipped with
Si[220] double crystal monochromator. The storage ring at SSRL
operated at 3.0 GeV and a maximum current of 100 mA. Data col-
lection at the gallium K edge was carried out in transmission and
fluorescence mode simultaneously, using ion chambers with a flow
of a gas mixture of helium and nitrogen, and a Lytle detector [10]
filled with argon gas. Higher order harmonics were rejected by
detuning the second monochromator crystal to 50% of maximum
intensity at the end of the scan. Data collection at the indium K
edge was only carried out in transmission mode, using ion cham-

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Ö. Topel et al. / Inorganica Chimica Acta 365 (2011) 220–224
Fig. 1. Representation of the heteroatomic In–S cage of [In4S4(C3H7NS)12](ClO4)4. Thermal ellipsoids are set to 50%, and all symmetry-equivalent atoms in the heterocubane
complex are included. For purposes of clarity, hydrogen atoms have been excluded, and three of the indium(III) ions have partially transparent DMTF ligands.
Table 2
atom, using the scattering factors f for neutral atoms, including
corrections for anomalous dispersion,
Crystallographic data on solid [In4S4(C3H7NS)12](ClO4)4 at room temperature.
D D
f0 and f00 [17], and values
[In4S4(C3H7NS)12](ClO4)4
for Compton scattering [18]. To receive a better alignment of the
intensity function, a Fourier back-transformation was applied to
eliminate spurious not related to any interatomic distances peaks
below 1.2 Å in the radial distribution function [19]. Least-squares
refinements of the model parameters were performed by means
Formula
C36H84Cl4 In4N12O16S16
2055.19
tetragonal
I-42 m (No. 121)
18.1125(15)
18.1125(15)
12.1492(11)
90
Molecular weight
Crystal system
Space group
a (Å)
b (Å)
c (Å)
of the STEPLR program [20] to minimizing the error square sum
P
U = w(s)[iexp(s) ꢀ icalc(s)]2, where w(s) is a weighting factor.
a
(°)
b (°)
90
c
(°)
90
3985.7(6)
V (Å3)
Table 3
T (K)
298(2)
Selected bond distances and angles from the crystal structure determination of solid
[In4S4(C3H7NS)12](ClO4)4; S1 and its symmetry-related counterpart S10 are sulfide
sulfurs, while S2 and S3 are N,N-dimethylthioformamide sulfurs.
Z
2
qcalc (g cmꢀ3
)
1.712
1.755
l
(mmꢀ1
)
Crystal size (mm)
h Range (°)
Index ranges
0.59 ꢁ 0.45 ꢁ 0.44
Bond
R (Å)
Angle
(°)
90.36(4)
1.59–25.02
ꢀ18 6 h 6 22, ꢀ22 6 k 6 20,
ꢀ14 6 l 6 14
10 872
1878 (0.0279)
full-matrix least-squares on F2
0.0306, 0.0815
0.0335, 0.0845 (all data)
0.06(3)
In1–S1
In1–S10
In–Smean (in cube)
In1–S2
In1–S3
2.594(1)
2.563(2)
2.584(1)
2.720(1)
2.669(2)
S1–In1–S1
S1–In1–S10
90.30(4)
Measured reflections
Unique reflections (Rint
Refinement method
Final R1, wR2 [I > 2s(I)]a
)
S1–In1–S3
S2–In1–S2
S2–In1–S3
89.28(4)
80.27(6)
88.47(4)
In–Smean (terminal)
2.704(1)
Absolute structure parameters
Largest difference in peak (e/Åꢀ3
Largest difference in hole (e /Åꢀ3
S1–In1–S2
S1–In1–S3
In1–S2–C2
In1–S3–C3
174.51(4)
179.48(5)
97.4(2)
)
)
0.743
ꢀ0.428
h
105.1(3)
P
P
P
P
½wðF2o ꢀ
a
R
values are defined as R1
¼
jjFoj ꢀ jFcjj= jFoj; jFoj; wR2
¼
h
ii
0:5
In–Smean
2.644(1)
P
overall
2
F2c ꢂ=
wðF20Þ
.

Ö. Topel et al. / Inorganica Chimica Acta 365 (2011) 220–224
223
Table 4
Bond distances, d (Å), Debye–Waller factors, r2 (Å2), and number of distances, n, for
4+
the DMTF solvated the gallium(III) and [In4S4(C3H7NS)12
]
in solid and solution as
determined by EXAFS and LAXS at room temperature; Eo (eV) is the refined threshold
energy and S2o is refined amplitude reduction factor.
So2
Sample
n
d
r2
Eo
Ga(CF3SO3)3 in solution, EXAFS
Ga–S
GaꢃꢃꢃC
4
4
8
12
2.233(1)
3.052(7)
3.44(1)
4.123(7)
4.48(2)
0.0124(2)
0.014(1)
0.010(2)
0.0055(9)
0.015(4)
10373.8(2)
1.04(2)
Ga–S–C
Ga–S–S
Ga–S–Ga–S
4 + 12
Solid [In4S4(C3H7NS)12](ClO4)4, EXAFS
In–SS
3
3
3
6
2.568(3)
2.661(3)
3.487(6)
0.0040(4)
0.0044(5)
0.0064(6)
0.011(4)
27946.1(2)
27946.0(2)
0.84(2)
0.87(2)
In–SDMTF
InꢃꢃꢃC
In–S–C
[In4S4(C3H7NS)12
In–SS
3.67(2)
4+
]
in solution, EXAFS
2.576(5)
3
3
3
6
0.0047(4)
0.0061(5)
0.0101(10)
0.030(12)
In–SDMTF
InꢃꢃꢃC
2.658(3)
3.424(8)
3.68(1)
In–S–C
[In4S4(C3H7NS)12
In–S
4+
]
in solution, LAXS
2.619(4)
3
1.5
4
6
3
0.0100(3)
0.0226(6)
0.0277(9)
0.0175(5)
0.025(3)
InꢃꢃꢃIn
3.622(3)
4.546(5)
5.837(4)
3.353(9)
In. . .S
InꢃꢃꢃS
InꢃꢃꢃC
3. Results and discussion
3.1. The dodecakis(N,N-dimethylthioformamide)tetrasulfido-
tetraindium(III) ion
Dodecakis(N,N-dimethylthioformamide)tetrasulfidotetraindi-
um(III) perchlorate, 1, [In4S4(SCHN(CH3)2)12](ClO4)4, crystallizes in
the tetragonal space group I-42 m (No. 121). The structure of the
4+
[In4S4(SCHN(CH3)2)12
]
ion is a highly symmetric heterocubane
with four indium(III) and four sulfide ions forming an almost reg-
ular cube with each indium binding to three sulfide ions and each
sulfide ion to three indium(III) ions. The In–S bond distances with-
in the cube are 2.5633(14) and 2.5942(9) Å, and the SS–In–SS
angles are 90.30(4) and 90.36(4)°. Each indium(III) ion additionally
binds three DMTF molecules at 2.6693(18) and 2.7198(12) Å com-
pleting an almost regular octahedral configuration around indium
with SDMTF–In–SDMTF angles of 89.28(4) and 80.27(6)°, and In–S–C
angles of 97.4(3) and 105.1(3)°, Fig. 1. The mean In–S bond dis-
tance in 1 is 0.02 Å longer, and the S–In–S angle much more close
to 90° than in the reported In4S4 clusters where the indium(III) ion
binds only one more additional group, Table S2. The In–S–In angle
is on the other hand somewhat smaller than in other reported In4S4
clusters. The perchlorate ion is disordered, and two positions of the
crystallographic independent oxygen atoms O1 and O2 were
refined with each set reaching occupancies of 47% and 53%, respec-
tively. Crystallographic data and selected bond distances and
angles in 1 are given in Tables 2 and 3.
LAXS data on a concentrated indium(III) trifluoromethanesulfo-
nate solution in DMTF, 0.763 mol dmꢀ3, confirms the presence of a
tetrameric complex almost identical to that described in the solid
state above. The mean In–S bond distance is 2.62(1) Å, and the
mean InꢃꢃꢃIn distance 3.62(1) Å, which is in full agreement with dis-
tances in 1. The strong contributions at 4.55(1) and 5.84(1) Å cor-
respond to InꢃꢃꢃS distances, Table 4, showing beyond any doubt that
the dominating species is the tetramer as these peaks should not
be present if a monomeric solvated indium(III) ion had been the
dominating one. The fit of LAXS data are given in Fig. 2, and the
refined structure parameters in Table 4. The EXAFS spectra of 1
and the DMTF solution of indium(III) trifluoromethanesulfonate
are identical (Fig. 3). Due to the short core hole life time, the
Fig. 2. (Top) LAXS radial distribution curves for a 0.763 mol dmꢀ3 N,N-dimethyl-
thioformamide solution of indium(III) trifluoromethanesulfonate. Upper part:
Separate model contributions (offset: 40) of the N,N-dimethylthioformamide
solvated indium(III) ion (black line), the trifluoromethanesulfonate ion (light grey
line) and N,N-dimethylthioformamide molecule (grey line). (Middle) Experimental
RDF: D(r)-4p
r2ro (solid line); sum of model contributions (grey line); difference
(light grey line). (Bottom) Reduced LAXS intensity functions s.i(s) (black thin line);
model sꢃicalc(s) (thick grey line).
information beyond the first scattering shell is very limited and
uncertain. (cf. Fig. 4) However, it was possible to resolve two differ-
ent In–S bond distances, In–SS = 2.57(1) and In–SDMTF = 2.66(1) Å,
which is in good agreement with the crystallographic data for 1
(Tables 3 and 4).
Dodecakis(N,N-dimethylthioformamide)tetrasulfidotetraindi-
um(III) perchlorate, 1, is novel in three respects: it is the first
(Ga/In)4S4 cluster with an octahedral configuration around the
metal ion, the first (Ga/In)4S4 cluster with simultaneous sulfur
electron-pair donor binding to the metal ion, and the first In4S4
cluster with an electron-pair donor binding to the metal. Previ-
ously, only one Ga4S4 complex with an electron-pair donor ligand
binding to the metal has been reported, [Ga4S4(NC9H18)4] [21].
3.2. DMTF solvated gallium(III) ion
The EXAFS data on the DMTF solvated gallium(III) in solution
give a mean Ga–S distance of 2.233(1) Å. The bond distances were
modeled with main contributions from Ga–S and GaꢃꢃꢃC single
back-scattering,
a three-leg back-scattering path within the
Ga–S–C entity, and strong multiple scattering within the tetrahe-
dral GaS4 core. The structure parameters are summarized in Table 4

224
Ö. Topel et al. / Inorganica Chimica Acta 365 (2011) 220–224
the DMTF solvated gallium(III) ion is four-coordinate, most proba-
bly in tetrahedral fashion. The large Debye–Waller factor of the
Ga–S distance, 0.0124(2) Å2, shows a wide distribution in the
Ga–S distances maybe caused by steric restrictions. The Ga–S–C
angle of 104.5°, estimated from Ga–S, Ga–S–C and GaꢃꢃꢃC back-scat-
tering paths within the Ga–S–C entity, is within the expected range
[4–7].
Acknowledgements
We gratefully acknowledge the Swedish Research Council, and
the Scientific and Technological Research Council of Turkey (TUBI-
TAK) BIDEB-2214 research fellowship programme for financial
support to Ö.T., the Department of Chemistry, Institute of Natural
Sciences of Akdeniz University, Antalya, Turkey, for giving leaving
permission to one of us (Ö.T.). Portions of this research were car-
ried out beam-line 4-1 at the Stanford Synchrotron Radiation
Lightsource (SSRL), a national user facility operated by Stanford
University on behalf of the U.S. Department of Energy, Office of
Basic Energy Sciences. The SSRL Structural Molecular Biology
Program is supported by the Department of Energy, Office of
Biological and Environmental Research, and by the National Insti-
tutes of Health, National Center for Research Resources, Biomedical
Technology Program. SSRL is acknowledged for the allocation of
beam time and laboratory facilities. M.Sc. O. Nikonova is acknowl-
edged for assisting in the recording of the infrared spectra.
Fig. 3. Fit of the EXAFS data for (a) a 1.35 mol dmꢀ3 N,N-dimethylthioformamide
solution of gallium(III) trifluoromethanesulfonate, (b) a 1.00 mol dmꢀ3 N,N-dim-
ethylthioformamide solution of indium(III) trifluoromethanesulfonate and (c)
[In4S4(C3H7NS)12]
4+ in solid state; black line experimental data, grey line calculated
model function using the parameters given in Table 4.
Appendix A. Supplementary material
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.ica.2010.09.011.
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Fig. 4. Fourier transforms for (a) a 1.35 mol dmꢀ3 N,N-dimethylthioformamide
solution of gallium(III) trifluoromethanesulfonate, (b) a 1.00 mol dmꢀ3 N,N-dim-
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