Sodium thiosulfonate salts: Molecular and supramolecular structural features and solution radiolytic properties

Article abstract of DOI:10.1039/c1dt10857c

Three sodium thiosulfonate salts, NaMeS₂O₂· H₂O, NaPhS₂O₂ and NaMeC₆H ₄S₂O₂ have been prepared by the direct reaction of the sodium sulfinate salts with elemental sulfur, a clean, benign route that produces no by-products. The structures of the phenyl (which crystallised as a hydrate, NaPhS₂O₂·1.5H₂O) and p-tolyl compounds were determined by X-ray crystallography. For the p-tolyl derivative, NaMeC₆H₄S₂O₂, the unexpected coordination of the pendant sulfur atom was found, a feature not reported previously for thiosulfonate salts, and observed only in two of the more common thiosulfate salts. Intermolecular CH/π interactions are postulated to contribute to the driving force of sulfur coordination, otherwise a different orientation of the aromatic rings would be expected. For NaPhS₂O ₂·1.5H₂O, the water ligands and thiosulfonate anions each contribute three oxygen atoms to form a NaO₆ coordination sphere. The thiosulfonate and water oxygens bridge to other sodium atoms forming a three-dimensional layer structure consisting of sheets of NaPhS ₂O₂·1.5H₂O with a hydrophilic interior layer, comprising the sodium ions, water ligands and -S₂O ₂^- groups, and a hydrophobic exterior formed by the phenyl substituent. The structure is further stabilised by an extensive H-bonding network between the ligated water and the non-coordinating thiosulfonate sulfur atom forming part of the hydrophilic layer and by weak intermolecular edge-to-face CH/π interactions between the sheets. Investigation of the radical chemistry of the three salts using pulse radiolysis indicated that oxidation of NaMeS₂O₂·H₂O involves formation of a sulfur-centred radical rather than hydrogen abstraction from the methyl substituent, whereas oxidation of the aromatic ring is the preferred pathway for the phenyl and p-tolyl derivatives.

Full text of DOI:10.1039/c1dt10857c

View Article Online / Journal Homepage / Table of Contents for this issue
This article is published as part of the Dalton Transactions themed issue entitled:
Self-Assembly in Inorganic Chemistry
Guest Editors Paul Kruger and Thorri Gunnlaugsson
Published in issue 45, 2011 of Dalton Transactions
Image reproduced with permission of Mark Ogden
Articles in the issue include:
PERSPECTIVE:
Metal ion directed self-assembly of sensors for ions, molecules and biomolecules
Jim A. Thomas
Dalton Trans., 2011, DOI: 10.1039/C1DT10876J
ARTICLES:
Self-assembly between dicarboxylate ions and a binuclear europium complex: formation of stable
adducts and heterometallic lanthanide complexes
James A. Tilney, Thomas Just Sørensen, Benjamin P. Burton-Pye and Stephen Faulkner
Dalton Trans., 2011, DOI: 10.1039/C1DT11103E
Structural and metallo selectivity in the assembly of [2 × 2] grid-type metallosupramolecular
species: Mechanisms and kinetic control
Artur R. Stefankiewicz, Jack Harrowfield, Augustin Madalan, Kari Rissanen, Alexandre N. Sobolev
and Jean-Marie Lehn
Dalton Trans., 2011, DOI: 10.1039/C1DT11226K
Visit the Dalton Transactions website for more cutting-edge inorganic and organometallic research
www.rsc.org/dalton

Dynamic Article Links
Dalton
Transactions
Cite this: Dalton Trans., 2011, 40, 12310
www.rsc.org/dalton
PAPER
Sodium thiosulfonate salts: Molecular and supramolecular structural features
and solution radiolytic properties†
Adam J Fischmann and Leone Spiccia*
Received 6th May 2011, Accepted 2nd September 2011
DOI: 10.1039/c1dt10857c
Three sodium thiosulfonate salts, NaMeS2O2·H2O, NaPhS2O2 and NaMeC6H4S2O2 have been prepared
by the direct reaction of the sodium sulfinate salts with elemental sulfur, a clean, benign route that
produces no by-products. The structures of the phenyl (which crystallised as a hydrate,
NaPhS2O2·1.5H2O) and p-tolyl compounds were determined by X-ray crystallography. For the p-tolyl
derivative, NaMeC6H4S2O2, the unexpected coordination of the pendant sulfur atom was found, a
feature not reported previously for thiosulfonate salts, and observed only in two of the more common
thiosulfate salts. Intermolecular CH/p interactions are postulated to contribute to the driving force of
sulfur coordination, otherwise a different orientation of the aromatic rings would be expected. For
NaPhS2O2·1.5H2O, the water ligands and thiosulfonate anions each contribute three oxygen atoms to
form a NaO6 coordination sphere. The thiosulfonate and water oxygens bridge to other sodium atoms
forming a three-dimensional layer structure consisting of sheets of NaPhS2O2·1.5H2O with a
-
hydrophilic interior layer, comprising the sodium ions, water ligands and -S2O2 groups, and a
hydrophobic exterior formed by the phenyl substituent. The structure is further stabilised by an
extensive H-bonding network between the ligated water and the non-coordinating thiosulfonate sulfur
atom forming part of the hydrophilic layer and by weak intermolecular edge-to-face CH/p interactions
between the sheets. Investigation of the radical chemistry of the three salts using pulse radiolysis
indicated that oxidation of NaMeS2O2·H2O involves formation of a sulfur-centred radical rather than
hydrogen abstraction from the methyl substituent, whereas oxidation of the aromatic ring is the
preferred pathway for the phenyl and p-tolyl derivatives.
complexes, viz., Au(I),9,10 Fe(II),11 Ru(II),12,13 Ag(I),14 Hg(II),14
Introduction
Pt(II)15,16 and Ir(III),17 have been reported in which the thiosulfonate
-
2-
Thiosulfonates (R-S2O2 ) are derivatives of thiosulfate, S2O3
,
commonly binds via the terminal sulfur atom, as is the case
for thiosulfate. Gold(I) thiosulfonates are the subject of several
patents,18–21 primarily aimed at potential application as sensitisers
in silver halide emulsions on colour photographic paper and also
as pharmaceuticals. Our general interest in copper(II) chemistry
and in the application of copper(II) thiosulfate/thiosulfonates
in gold leaching previously led us to study the structure and
properties of copper(II) complexes of formula [LCu(R-S2O2)]+ and
[LCu(S2O3)], where L is either the tripodal tetradentate ligand,
tris(2-aminoethyl)amine or a derivative thereof,22,23 and a dinuclear
gold(I) thiosulfonate complex held together by an aurophilic
interaction.24
Information about the X-ray structure of simple thiosulfonate
salts is quite scarce. Foss and co-workers published papers on
structural aspects of thiosulfonate compounds,25–34 including X-
ray diffraction analyses of the crystalline alkali metal salts. In their
early work28 unit cell dimensions were given for NaMeC6H4S2O2,
KMeC6H4S2O2 and KMeS2O2, but there have been no subsequent
full structure determinations reported. Despite quite the variety
of known thiosulfonates, X-ray crystal structures have been de-
termined only for NaMeS2O2·H2O33 and NH4MeS2O2,35 and for a
in which an organic group replaces one oxygen atom. These
compounds have been of interest in the biomedical field where one
major focus of investigation has been their biological properties
and their potential application as antidotes for cyanide poisoning,
H2S detoxification, fungicides and bacteriocides.1–8
The structure, chemical properties and coordination chemistry
of thiosulfonates have not been examined in great detail when
compared to thiosulfate. Nevertheless, a variety of thiosulfonate
School of Chemistry, Monash University, Victoria, 3800, Australia.
E-mail: leone.spiccia@monash.edu; Fax: 61 3 9905 4597; Tel: 61 3 9905
4526
† Electronic supplementary information (ESI) available: Fig. S1 (inter-
sheet and CH/p interactions in NaMeC6H4S2O2); Fig. S2 (pos-
sible coordination environment sodium ion in tris(O-chelate) iso-
mer of NaMeC6H4S2O2); Fig. S3 (edge-to-face CH/p interactions
in NaPhS2O2·1.5H2O); Fig. S4 (crystal packing of NaMeC6H4SO3);
and Table S1 (composition of samples for pulse radiolysis experi-
ments with MeS2O2-). CCDC reference numbers 823756 and 823757
for NaMeC6H4S2O2 and NaPhS2O2·1.5H2O, respectively. For ESI and
crystallographic data in CIF or other electronic format see DOI:
10.1039/c1dt10857c
12310 | Dalton Trans., 2011, 40, 12310–12319
This journal is
The Royal Society of Chemistry 2011
©

number of Te(II) complexes.27,31,36–39 Herein, we report the synthesis
and X-ray crystal structures of two sodium thiosulfonate salts,
NaMeC6H4S2O2 and NaPhS2O2·1.5H2O, which have been found
to exhibit interesting molecular and supramolecular structural
features that influence the sodium coordination environment and
contribute to the stabilization of the crystal lattice. Additionally,
pulse radiolysis studies of thiosulfonate salts were carried out
to establish whether thiosulfonates form radical anions, the
impetus being previous pulse radiolysis studies of thiosulfate
∑
which have established the formation of radical anions (S2O3 - and
∑
S4O6 -) from the one-electron oxidation of thiosulfate40–42 and are
thought to be intermediates in many kinetic processes involving
thiosulfate.43–47
3
Results and discussion
The two general routes for the preparation of thiosulfonate salts
involve either sulfonyl chlorides1,48–50 or sulfinate salts (Fig. 1).4,51–53
In this study, sodium sulfinate precursors were preferred since they
are generally crystalline solids of low toxicity whereas sulfonyl
chlorides are corrosive solids or liquids with a pungent odour.
Reactions involving the latter also involve the use of corrosive and
toxic sodium sulfide as the nucleophile and sodium chloride is a by-
product, which would need to be separated from the thiosulfonate
product. The sulfinate route, on the other hand, uses non-toxic
elemental sulfur and is free of by-products. Three thiosulfonate
salts (NaRS2O2) were prepared; sodium methanethiosulfonate
(R = Me), sodium benzenethiosulfonate (R = Ph), and sodium
p-toluenethiosulfonate (R = MeC6H4). The methanethiosulfonate
salt was isolated as a monohydrate (NaMeS2O2·H2O) whereas the
aryl derivatives were both anhydrous compounds. Recrystallisa-
tion from EtOH was sufficient to achieve analytical purity, as
determined by 1H-NMR spectroscopy and elemental analysis.
Fig. 2 (a) Molecular structure of NaMeC6H4S2O2. A mirror plane
(pale blue) bisects the molecule through S(1), S(2), C(1), C(4) and C(5).
Equivalent atoms (*) are generated by the symmetry operation x, - y, z.
Hydrogen atoms omitted for clarity. (b) Coordination geometry of the Na+
ion in NaMeC6H4S2O2 (see Table 2 for symmetry operations).
-
consists of MeC6H4S2O2 anions coordinated to sodium ions
using both of their oxygen atoms in addition to the terminal
sulfur (Fig. 2). Each donor atom simultaneously chelates to one
sodium ion and bridges to another. As a consequence of the mirror
plane, which bisects the molecule through atoms C(5), C(4), C(1),
S(2) and S(1), the only full-occupancy atoms are C(2) and C(3),
their associated hydrogen atoms H(2) and H(3), and O(1). The
anion itself has an overall Cs symmetry, which is governed by the
geometry of the thiosulfonate group. Each six coordinate sodium
ion has a O4S2 donor set and is in a highly distorted geometry
that cannot be described as octahedral, viz., the largest angle
(O(1)5–Na(1)–O(1)1) is only 136.38(7)◦ whereas the S–Na–S angle
is 94.31(3)◦ (Fig. 2(b), Table 1). The four oxygen atoms are in a
‘squashed’ tetrahedral arrangement imposed by the presence of
the weakly coordinating sulfur atoms. The Na(1)–S(1) distance,
while long, is nevertheless a bonding interaction as defined in the
SHELX-9754 program (viz. distance is less than the sum of the
Fig. 1 Synthetic routes to sodium thiosulfonate salts.
Crystal structures
X-Ray crystallography indicated that the NaMeC6H4S2O2 salt
was an anhydrous compound whereas the phenyl derivative was
hydrated (NaPhS2O2·1.5H2O), despite the elemental analysis of
the bulk sample being consistent with an anhydrous composi-
tion. The water molecules were evidently incorporated during
the recrystallisation of the bulk material. Notably, Foss28 for
˚
˚
˚
covalent radii plus 0.5 A; i.e. 3.124 A < 3.39 A). Thus, the sulfur
atoms influence the Na geometry.
This compound is the first crystallographically characterised
example of an S-coordinated sodium thiosulfonate complex. Only
two alkali metal thiosulfate compounds share this feature; a pair of
coordination polymers consisting of glycine, thiosulfate and either
sodium or potassium.55 The Na–S distance in NaMeC6H4S2O2
-
MeC6H4S2O2 found that a dihydrate and an anhydrous sodium
salt crystallised from 96% EtOH depending on the temperature,
but these were not examined by X-ray crystallography beyond
determining the space group and unit cell dimensions.
˚
(3.1242(7) A) is longer than in the sodium coordination polymer
˚
(2.899(1) and 3.014(1) A), but slightly shorter than in the
NaMeC6H4S2O2
˚
potassium compound (3.1527(9), 3.189(1) A), as is expected given
the larger size of the K+ ion.
Another depiction of the coordination geometry around the
sodium ion is shown in Fig. 3(a); the sodium ions are linked by
A suitable crystal for X-ray diffraction was obtained on recrystalli-
sation of NaMeC6H4S2O2 from EtOH and the structure was solved
in the monoclinic space group C2/m. The molecular structure
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 12310–12319 | 12311
©

◦
˚
Table 1 Selected bond distances (A) and angles ( ) in NaMeC6H4S2O2
(esd in parentheses)
S(1)–S(2)
1.9504(7)
3.1242(7)
3.1242(7)
1.464(1)
1.464(1)
1.767(2)
2.297(1)
74.89(2)
74.89(2)
85.69(3)
113.9(1)
105.75(6)
105.75(6)
110.35(5)
110.35(5)
110.59(7)
100.06(7)
134.89(5)
76.80(4)
76.80(4)
134.89(5)
Na(1)–O(1)4
Na(1)–O(1)5
Na(1)–O(1)1
Na(1)–S(1)1
Na(1)–S(1)6
O(1)–Na(1)1
2.297(1)
2.416(1)
2.416(1)
3.1242(7)
3.1242(7)
2.416(1)
S(1)–Na(1)1
S(1)–Na(1)2
S(2)–O(1)
S(2)–O(1)3
S(2)–C(1)
Na(1)–O(1)
S(2)–S(1)–Na(1)1
S(2)–S(1)–Na(1)2
Na(1)1–S(1)–Na(1)2
O(1)–S(2)–O(1)3
O(1)–S(2)–C(1)
O(1)3–S(2)–C(1)
O(1)–S(2)–S(1)
O(1)3–S(2)–S(1)
C(1)–S(2)–S(1)
O(1)–Na(1)–O(1)4
O(1)–Na(1)–O(1)5
O(1)4–Na(1)–O(1)5
O(1)–Na(1)–O(1)1
O(1)4–Na(1)–O(1)1
O(1)5–Na(1)–O(1)1
O(1)–Na(1)–S(1)1
O(1)4–Na(1)–S(1)1
O(1)5–Na(1)–S(1)1
O(1)1–Na(1)–S(1)1
O(1)–Na(1)–S(1)6
O(1)4–Na(1)–S(1)6
O(1)5–Na(1)–S(1)6
O(1)1–Na(1)–S(1)6
S(1)1–Na(1)–S(1)6
S(2)–O(1)–Na(1)
S(2)–O(1)–Na(1)1
Na(1)–O(1)–Na(1)1
136.38(7)
133.76(3)
100.49(3)
90.13(4)
59.49(3)
100.49(3)
133.76(3)
59.49(3)
90.13(4)
94.31(3)
146.90(7)
109.88(6)
103.20(4)
1
Symmetry operations used to generate equivalent atoms: (1) - x - /2, - y
1
1
- /2, - z; (2) x + 1/2, y + 1/2, z; (3) x, - y, z; (4) - x - 1, y, - z; (5) x - /2,
1
1
1
- y - /2, z; (6) x - /2, y - /2, z.
two m2-(O)2 bridges and one m2-(S)2 bridge. Each oxygen atom in
the m2-(O)2 bridges has two inequivalent Na–O bonds (2.297(1)
˚
and 2.416(1) A), whereas all the Na–S distances are equivalent
˚
(3.124(1) A). The connection between Na(1) and the neighbouring
Na atoms is highlighted by the three planes drawn in Fig. 3(b).
Bridging to two of the Na atoms is through oxygen atoms while
sulfur atoms are involved in bridging to the third. The two oxygen-
containing planes are twisted relative to each other by 66.75(6)◦,
and the angle between the sulfur plane and each oxygen planes is
84.38(2)◦.
Fig. 3 (a) Coordination geometry (the filled planes highlight the m3
bridging mode of every oxygen and sulfur coordinated to the sodium); and
(b) distorted-T geometry of the sodium ion in NaMeC6H4S2O2, symmetry
3
1
operations: (7) - x - 1, - y - 1, - z; (8) - x - /2, - y - /2, - z.
The planes of Na2S2 and Na2O2 units emphasise the T-shaped
arrangement of the sodium ions around the central Na. The
axial angle, Na(1)8–Na(1)–Na(1)1, is 162.01(5)◦ and the angle
from the axial to the equatorial sodium, Na(1)1–Na(1)–Na(1)7
is 99.00(3)◦ (the angle involving Na(1)8 is equivalent, since both
Na(1)8 and Na(1)7 are related by symmetry). This arrangement
of the bridging planes organises the structure into sheets along
the ab-plane (Fig. S1†), which interact with neighbouring sheets
via CH/p interactions between the methyl groups and the closest
aromatic ring (Fig. 4). Despite the weak nature of individual
CH/p interactions, the cooperation of many such interactions
can provide a large contribution to the overall enthalpy of the
crystal.56 These CH/p interactions are likely to be responsible for
the coordination of the sulfur atoms, since if the sodium ion were
chelated by three pairs of oxygen atoms, the aromatic rings would
point in different directions (Fig. S2†), and perhaps the crystal
packing arrangement would be less favourable.
Fig. 4 Inter-sheet connectivity in NaMeC6H4S2O2: (a) crystal packing
(view rotated 45◦ around the c axis, perpendicular to the ab-plane); (b)
CH/p interactions between tolyl groups from adjacent sheets.
Due to the disorder in the methyl group, the exact CH/p
interactions linking the ab-sheets cannot be determined. The
interaction is therefore discussed in terms of C ◊ ◊ ◊ C distances, and
then the average of the C(5B) and C(5B¢) hydrogen atom positions.
The distance between the plane of the aromatic ring (defined by
atoms C(1)–C(4) and C(2¢) and C(4¢), generated by x, - y, z)
˚
3.721 A for C(4) and C(3), respectively. The CH/p interactions
3
are therefore best described as h ; however, the distance to C(4) is
significantly shorter, indicating interactions unequal in strength.
In order to estimate the C–H ◊ ◊ ◊ C distances, the average position
of the H(5B) hydrogen atoms was used, in line with the mirror
plane of the MeC6H4S2O2- anion, assuming the C(4)–C(5)–H(5B*)
-
and the methyl carbon of the adjacent MeC6H4S2O2 ion, C(5),
˚
is 3.523(6) A; the distances to the closest ring carbons are 3.590,
12312 | Dalton Trans., 2011, 40, 12310–12319
This journal is
The Royal Society of Chemistry 2011
©

◦
˚
Table 2 Selected bond distances (A) and angles ( ) in NaPhS2O2·1.5H2O (esd in parentheses)
S(1)–S(2)
S(2)–O(1)
S(2)–O(2)
1.9780(7)
1.460(2)
1.469(1)
1.780(2)
2.355(2)
2.400(2)
2.408(2)
Na(1)–O(2 W)
2.423(1)
2.479(2)
2.486(2)
2.400(2)
2.479(2)
2.355(2)
2.423(1)
Na(1)–O(2)3
Na(1)–O(1 W)
S(2)–C(1)
O(1 W)–Na(1)2
Na(1)–O(1)1
O(2)–Na(1)3
Na(1)–O(1 W)2
Na(1)–O(2)
O(1)–Na(1)1
O(2 W)–Na(1)1
Thiosulfonate
Na coordination (non-axial)
O(1 W)1–Na(1)–O(1 W)
O(1 W)2–Na(1)–O(2 W)
O(1)1–Na(1)–O(2)3
O(1)1–Na(1)–O(2 W)
O(2 W)–Na(1)–O(1 W)
O(1)1–Na(1)–O(2)
O(2)–Na(1)–O(2)3
O(2)–Na(1)–O(1 W)
O(1 W)1–Na(1)–O(2)3
O(2)–Na(1)–O(2 W)
O(1)1–Na(1)–O(1 W)2
O(2)3–Na(1)–O(1 W)
Na coordination (axial)
O(2 W)–Na(1)–O(2)3
O(1)1–Na(1)–O(1 W)
O(1 W)2–Na(1)–O(2)
O(1)–S(2)–O(2)
O(1)–S(2)–C(1)
O(2)–S(2)–C(1)
O(2)–S(2)–S(1)
O(1)–S(2)–S(1)
C(1)–S(2)–S(1)
S(2)–O(2)–Na(1)
S(2)–O(2)–Na(1)3
S(2)–O(1)–Na(1)1
Na bridging
115.13(8)
106.26(9)
106.57(8)
111.54(6)
111.60(7)
104.92(7)
123.08(8)
144.72(9)
154.69(9)
79.64(6)
80.85(6)
83.63(5)
83.93(5)
84.23(5)
85.42(6)
88.24(5)
90.61(6)
91.00(5)
102.51(5)
105.03(6)
109.31(6)
Na(1)–O(2)–Na(1)3
Na(1)2–O(1 W)–Na(1)
Na(1)–O(2 W)–Na(1)1
91.76(5)
100.36(6)
114.32(9)
162.82(5)
166.38(6)
169.38(6)
Symmetry operations used to generate equivalent atoms: (1) 1 - x, y,1/2 - z; (2) 1 - x, - y - 1, 1 - z; (3) 1 - x, - y, 1 - z.
angle to be 109.5◦ and the C–H distance to be 0.98 A. The
distances between this average position, H(5B)*, and C(4) and
˚
˚
Table 3 Hydrogen bonding in NaPhS2O2·1.5H2O (distances in A and
angles in ◦
)
˚
C(3)/C(3)¢, are 2.72 and 2.86 A, respectively, well within the range
D–H
H ◊ ◊ ◊ A
D ◊ ◊ ◊ A
∠DHA
of CH/p interactions, which has been established from analysis of
O(1 W)–H(1 W) ◊ ◊ ◊ S(1)4
O(1 W)–H(2 W) ◊ ◊ ◊ S(1)5
O(2 W)–H(3 W) ◊ ◊ ◊ S(1)5
C(2)–H(2) ◊ ◊ ◊ O(1)4
0.83(3)
0.82(3)
0.85(3)
0.94(2)
2.59(3)
2.48(3)
2.53(3)
2.54(2)
3.396(2)
3.279(2)
3.344(1)
3.471(2)
165(3)
165(3)
163(3)
171(2)
˚
crystal structure databases to be 2.87 0.13 A for transition metal
complexes,57 and 2.72 0.18 A for purely organic compounds.
58
˚
Symmetry operations used to generate equivalent atoms: (4) x, - y, z +1/2;
(5) x, y - 1, z.
NaPhS2O2·1.5H2O
Crystals of NaPhS2O2·1.5H2O suitable for X-ray crystallography
were grown by slow evaporation of a solution of NaPhS2O2 in 96%
EtOH. The structure was solved in the monoclinic space group
C2/c. The molecular structure (Fig. 5) has some resemblance
to that of NaMeC6H4S2O2 but the donor set of the sodium
ion is quite different due to the presence of the water ligands
(see Fig. 5(b)). While the anion possesses Cs symmetry, with
the mirror plane passing through C(4), C(1), S(2) and S(1),
the asymmetric unit has lower symmetry due to coordination
of water molecules to Na(1). Na(1) is six-coordinate, and the
donor set consists of three water oxygens and three thiosulfonate
oxygens (from three independent anions) in a fac arrangement
(Fig. 5(b)). There is only a small difference between the Na–O
distances for water vs. thiosulfonate coordination (av. 2.436(2)
The water molecules also bridge pairs of S(1) atoms by hydrogen
bonding, each one donating two hydrogen bonds, such that three
of the six H-bonds are to a single S(1), and the rest are to three
separate S(1) atoms (Fig. 6). The geometric parameters (Table
3) indicate hydrogen bonds of moderate to weak strength in
the Jeffrey59 classification; although D–H ꢀ H ◊ ◊ ◊ A and DHA
angles (>160◦) suggest that they are too well directed to be purely
electrostatic interactions. Since sulfur is larger than oxygen and
nitrogen, longer D ◊ ◊ ◊ A distances are expected than in the Jeffrey
classification. A CCD survey of (O,N)–H ◊ ◊ ◊ S hydrogen bonding60
revealed that for thiones (R1R2C S), the average S ◊ ◊ ◊ H and
˚
˚
and 2.414(2) A, respectively). The Na ion is distorted octahedral;
S ◊ ◊ ◊ O distances are 2.42(2) and 3.32(1) A, respectively, whereas for
axial angles of 162.82(5)◦, 166.38(6)◦ and 169.82(5)◦ and non-axial
angles ranging from 79.64(6)◦ to 109.31(6)◦ (Table 2). Despite
the terminal sulfur not binding to Na+, the S–S bond distance is
indistinguishable from that in NaMeC6H4S2O2, suggesting weak
sulfur coordination in this compound. O(1 W) and O(1 W)2 bridge
to the symmetry-generated Na(1)2, forming a four-membered ring,
as do O(2) and O(2)3 (to Na(1)3). O(2 W) straddles over the eight-
membered ring (comprising the SO2 moiety of two anions and
two Na ions) by bridging the two Na ions in the ring, Na(1) and
Na(1)1.
S ◊ ◊ ◊ N–H interactions the corresponding distances were 2.50(1)
˚
and 3.43(1) A, respectively. More relevant examples, in which
sulfur is negatively charged, are zinc thiolate complexes.61 In
[TmPh][ZnSCH2C(O)NHPh], the intramolecular hydrogen bond
is characterised by N ◊ ◊ ◊ S and H ◊ ◊ ◊ S separations of 3.058(4) and
◦
˚
2.53(4) A, respectively and N–H ◊ ◊ ◊ S angle of 125 in agreemen◦t
˚
˚
with the respective values of 2.49(2) A, 2.936(2) A and 118(2)
for [Ph(pztBu)BttBu][Zn(SC6H4o-NHC(O)But)].61 In each of these
compounds, the H ◊ ◊ ◊ S distance is comparable to that found in
NaPhS2O2·1.5H2O.
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 12310–12319 | 12313
©

Fig. 6 (a) Hydrogen bonding network in NaPhS2O2·1.5H2O; (b) Hydro-
gen-bonded water bridges in NaPhS2O2·1.5H2O (phenyl hydrogens, other
sodium ions and further hydrogen bonding to the sulfur atoms omitted for
clarity. (1) 1 - x, y,1/2 - z; (4) x, - y,1/2+ z; (5) x, y - 1, z; (6) x, - y, z -
Fig. 5 (a) Molecular structure of NaPhS2O2·1.5H2O including sodium
ions but excluding the water molecules and aromatic hydrogen atoms.
1
1/2; (7) 1 - x, y - 1,1/2 - z; (8) x, - y, z - /2.
-
(b) Arrangement of water molecules and PhS2O2 anions around Na(1);
equivalent atoms generated by the symmetry operations: (1) 1 - x, y,1/2 -
z; (2) 1 - x, - y - 1, 1 - z; (3) 1 - x, - y, 1 - z.
The top-down view (Fig. 7) shows more clearly how the
hydrogen bonding chain extends along the c-axis in a ladder-like
arrangement, where the O(1 W) water molecules bridge adjacent
S(1) atoms to form the sides of the ladder and the O(2 W) water
molecules form the rungs of the ladder between opposite S(1)
atoms. The hydrogen bonding ladder network can be seen in Fig.
8 (middle panel) within the context of the full structure.
Fig. 7 Water–thiosulfonate hydrogen bonding topology, looking down
the b-axis; phenyl hydrogens and sodium ions omitted for clarity;
apostrophes (’) indicate complementary atoms.
The three-dimensional structure of NaPhS2O2·1.5H2O consists
of sheets in the bc-plane, with the phenyl rings on the exterior
of the sheets, and the water molecules and sodium ions in the
interior (seen clearly in Fig. 8 (bottom panel)). This arrangement
resembles that found in the structures of dinuclear Cr(III),
Rh(III) and Rh(III)–Cr(III) aqua ions62–64 of composition [M1M2(m-
OH)2(OH2)8](CH3)3C6H2SO3)4·4H2O, in which the aryl groups of
4). These H ◊ ◊ ◊ C separations for intermolecular CH/p interactions
are within the range reported in a survey of organic compounds
58
˚
in the CSD; average H ◊ ◊ ◊ C separation of 2.91 0.12 A.
-
the sulfonate anions project away from the M(III)/aqueous/SO3
Pulse radiolysis studies
central layer, and sodium p-toluenesulfonate (Fig. S4†).65 The
sheets themselves are weakly connected by edge-to-face CH/p
interactions between the phenyl rings. There are two C–H donor
groups, C(4)–H(4) and C(5)–H(5); H(4) has CH/p interactions
with each carbon atom of the neighbouring ring (Fig. S3†),
whereas H(5) only interacts with the C(3) atom ofthe neighbouring
ring. The position of H(4) is slightly offset from the centre of the
neighbouring ring, resulting in a range of C–H ◊ ◊ ◊ C distances
Since thiosulfonates were being investigated as organic analogues
of thiosulfate, we investigated whether oxidation could proceed via
a radical mechanism, as has been shown to occur for thiosulfate
with a variety of oxidants.40–46 Pulse radiolysis was considered
an ideal technique for this purpose as it can produce hydroxyl
radicals at various concentrations, and any transients formed
thereafter can be followed by changes to the UV-visible spectrum.
Competition kinetics with thiocyanate were used to determine the
rate of the reaction of hydroxyl radicals with thiosulfonates, as
˚
(2.85(3) to 3.07(3) A). The lone CH/p interaction from the meta
˚
H(5) is within the range of those from H(4), i.e. 3.00(3) A (Table
12314 | Dalton Trans., 2011, 40, 12310–12319
This journal is
The Royal Society of Chemistry 2011
©

Analysis of competition kinetics with SCN- is straightforward
but the following assumptions are made: (i) the reactions are
˚
Table 4 CH/p interactions in NaPhS2O2·1.5H2O (distances in A and
angles in ◦
)
∑
-
simple bimolecular processes; (ii) (SCN)2 is the only absorbing
species at 480 nm; and (iii) there are no further competing reactions
in the time frame of interest.69 These conditions are satisfied for
D–H
H ◊ ◊ ◊ A
D ◊ ◊ ◊ A
∠DHA
C(4)–H(4) ◊ ◊ ◊ C(1)6
C(4)–H(4) ◊ ◊ ◊ C(2)6
C(4)–H(4) ◊ ◊ ◊ C(3)6
C(4)–H(4) ◊ ◊ ◊ C(4)6
C(4)–H(4) ◊ ◊ ◊ C(5)6
C(4)–H(4) ◊ ◊ ◊ C(6)6
C(5)–H(5) ◊ ◊ ◊ C(3)6
0.94(3)
0.94(3)
0.94(3)
0.94(3)
0.94(3)
0.94(3)
0.97(2)
3.00(3)
3.07(3)
3.02(3)
2.89(3)
2.85(3)
2.92(3)
3.00(3)
3.918(3)
3.832(3)
3.626(3)
3.498(2)
3.627(3)
3.846(3)
3.627(3)
64(2)
39(2)
24(2)
24(2)
40(2)
67(2)
24(2)
-
the case of MeS2O2 . The rate constant k for the reaction of the
substrate with HO∑ can therefore be calculated using eqn (1):70,71
A0
A
k
[X]
=1+
(1)
kref [SCN−]
1
Symmetry used to generate equivalent atoms: (6) 1/2 - x, y - /2,1/2 - z.
where [X] is the concentration of the substrate, A0 is the absorbance
in the absence of X, and A is the absorbance in the presence
of a certain concentration of X. Therefore, a plot of A0/A vs.
[X]/[SCN-] yields a straight line with an intercept of unity and
a slope of k/kref. Since kref is known, k is easily obtained from a
linear fit of the data (Fig. 9). To measure the rate constant for the
reaction of MeS2O2- with HO∑ by competition kinetics with SCN-,
the concentration of SCN- was kept constant at 20 mM, [MeS2O2 ]
-
was varied from 0.1 to 15 mM, and the ionic strength was adjusted
to 0.09 M using NaClO4. The absorbance at 480 nm was recorded
at 40 ns intervals. Each measurement is the average of ten pulses,
and repeated radiolysis of the solution did not significantly affect
the absorbance value.
Fig. 9 Relative rate plot for the reaction of MeS2O2 with HO∑ in the
-
presence of SCN- (20 mM). Dose = 101 4 Gy/pulse (by SCN- dosimetry).
Using the accepted rate constant for the reaction of HO∑ with
SCN- of 1.1 ¥ 1010 M-1 s-1, a rate constant for the reaction of
MeS2O2- with HO∑ of 3.4 ( 0.1)¥1010 M-1 s-1 was determined from
the data in Fig. 9. For comparison, the analogous rate constant for
thiosulfate was determined by Scho¨nesho¨fer40 to be 8 ¥ 109 M-1 s-1,
and was subsequently refined by Mehnert et al.42 to 7.8 ( 2.1)¥109
M-1 s-1. However, Mehnert et al.42 assigned this rate constant to
the formation of an S2O32-–HO∑ adduct. Such a fast reaction
rate is indicative of diffusion-controlled reactions, as would be
Fig. 8 Crystal packing of NaPhS2O2·1.5H2O, showing sheets in the
bc-plane; viewed down the (top panel) a-axis (middle panel) b-axis and
(bottom panel) c-axis.
the reaction product does not absorb appreciably in the accessible
spectral range (typically 300–500 nm). Thiocyanate is used as a
dosimetry standard for pulse radiolysis since it forms a transient
∑
thiocyanate radical anion dimer (SCN)2 -, which has a strong
expected for the one-electron oxidation of the terminal sulfur.
∑
visible absorption (emax = 7600 M-1 cm-1 at lmax 480 nm).66 The
rate constant for the reaction of thiocyanate with HO∑ is generally
accepted to be 1.1 ¥ 1010 M-1 s-1,67 although a more recent
measurement found it to be slightly faster (1.4 ¥ 1010 M-1 s-1).68 The
rate of the competing reaction can be determined from the decrease
in the absorbance at 480 nm as the substrate concentration
increases.
Structural differences between S2O3 and S2O3 are expected to
be minimal,72 so the lack of structural reorganisation should allow
a rapid electron transfer reaction. The same argument applies to
2-
-
∑
-
the formation of MeS2O2 from MeS2O2 (where the unpaired
electron is on the terminal sulfur atom).
However, in contrast to thiosulfate, the organic moiety of
MeS2O2- permits an alternative reaction pathway; hydrogen atom
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 12310–12319 | 12315
©

abstraction from the methyl group. Attack on the methyl group of
∑
-
-
MeS2O2 would yield a carbon-centred radical, i.e. CH2S2O2 ,
a process with a higher activation barrier than one-electron
oxidation of sulfur, since structural reorganisation would need
to occur to adopt the trigonal planar geometry of a carbon-
centred radical.73 For the structurally similar methanesulfonate
compound, hydrogen atom abstraction was postulated to be the
result of its reaction with the hydroxyl radical.74 The rate constant
measured for that reaction was 1.24( 0.07)¥107 M-1 s-1, cf ., 1.21
0.4 ¥ 108 M-1 s-1 for the corresponding reaction with methane.75
Rate constants for hydrogen atom abstraction from a variety of
saturated organic compounds are listed in Table 5. Since the rate
Scheme 1 Reaction of the hydroxyl radical with (a) thiols, (b) de-
protonated thiols and (c) methanethiosulfonate, and formation of the
∑
corresponding radicals, RS∑ and MeS2O2 , respectively.
-
constant measured in our study for the reaction of MeS2O2 with
HO∑ is much faster, hydrogen abstraction was probably not the
dominant process.
containing aromatic compounds such as thiophenols.78,83 In the
case of thiophenol,83 ~27% of the thiophenol that reacted with
the hydroxyl radical was converted into hydroxycyclohexadienyl
radicals, and a similar observation was made for the substituted
thiophenols 4-methylthiophenol78 and thiosalicylic acid;78 the
yields of hydroxycyclohexadienyl-type radicals were 25% and 18%,
respectively.
A similar situation occurs for aliphatic thiols, where competition
would be expected between hydrogen atom abstraction and
oxidation of the sulfur atom. Invariably, the one-electron oxidation
of a thiol to form thiyl radicals (Scheme 1a and 1b) is observed,
and is characterised by rate constants of the order of 109 to 1010
M-1 s-1 (Table 6). These rate constants are close to the diffusion
controlled limit, and imply that very little structural reorganisation
occurs from thiol to thiyl radical. Given that the rate constant for
the reaction of MeS2O2- with HO∑ is in this range, rather than that
of hydrogen atom abstraction, it can be concluded that oxidation
of the terminal sulfur atom (Scheme 1c) is the dominant process.
For the aromatic thiosulfonates, a third reaction pathway is
possible, viz. attack by the hydroxyl radical on the aromatic
ring, forming hydroxycyclohexadienyl-type radicals, which absorb
strongly in the UV region. Such radicals have been observed
for a variety of aromatic hydrocarbons,79–82 as well as sulfur-
Pulse radiolysis of N2O-saturated solutions of the two aromatic
-
thiosulfonates, MeC6H4S2O2- and PhS2O2 , resulted in absorbance
∑
peaks at ~325 and ~310 nm, respectively. Since the MeS2O2
radical did not exhibit any absorbance features, it was concluded
that sulfur-centred thiosulfonate radicals do not absorb between
300 and 500 nm. The transient absorbance spectrum observed
upon reaction of MeC6H4S2O2 or PhS2O2 with HO∑ is therefore
most likely due to the formation of hydroxycyclohexadienyl-
type radicals. Pulse radiolysis of N2O-saturated solutions of
NaMeC6H4SO3 (which cannot form a sulfur-centred radical) gave
a similar spectrum, with lmax at ~330 nm, again indicative of the
formation of hydroxycyclohexadienyl-type radicals (Fig. 10). The
rates of formation of the hydroxycyclohexadienyl-type radicals
-
-
-
Table 5 Comparison of rate constant for the reaction MeS2O2 and
2-
S2O3 with hydroxyl radicals with rate constants for hydrogen atom
abstraction from saturated organic compounds by the hydroxyl radical76
-
-
from MeC6H4S2O2 and PhS2O2 were not measured, as these are
not sulfur centred oxidations.
Compound
10-8 ¥ k (M-1 s-1) Compound
10-8 ¥ k (M-1 s-1)
-
2-
MeS2O2
340
S2O3
78
7.0
18
Methanol
Ethanol
1-Propanol
2-Propanol
9.02
17.9
27.0
0.0338
Propionate
n-Butyrate
n-Hexanoate 38.9
Glycine 29
2-Methyl-2-propanol 5.0
Acetonitrile 0.22
Propionitrile 0.71
Cyanoacetate 0.15
Formate
Acetate
30
0.7
Table 6 Rate constants for formation of thiyl radicals from thiols and
hydroxyl radicals
Compound
10-8 ¥ k (HO∑+S) (M-1 s-1)
pH
Thioglycolic acida
Methyl thioglycolatea
Thiolactic acida
60, 55
6.6. 11.1
5.1, 10.6
7.2, 10.8
6.0, 10.7
5.8, 10.8
5.4, 11.0
2,11
210, 180
170,160
300, 210
190, 180
80, 79
40, 40
24, 24
b-Mercaptopropionic acida
Cysteinea
S-Methylcysteinea
4-Methylthiophenolb
2-Thiosalicylic acidb
7, 11
Fig. 10 Transient UV-visible absorbance spectrum from pulse radiolysis
of an N2O-saturated solution of a 10 mM solution of NaMeC6C4SO3 (open
circles and broken line) and a 1 mM solution of NaMeC6H4S2O2 (crosses
and solid line). Error bars represent one standard deviation).
a Hoffman and Hayon,77 determined using thiocyanate method, k(HO∑ +
SCN-) = 1.1 ¥ 1010 M-1 s-1 ( 15%); b Dey et al.,78 rate constants determined
directly from absorbance changes.
12316 | Dalton Trans., 2011, 40, 12310–12319
This journal is
The Royal Society of Chemistry 2011
©

Table 7 Crystal data for NaMeC6H4S2O2 and NaPhS2O2·1.5H2O
Conclusion
Crystal data
NaMePhS2O2
NaPhS2O2·1.5H2O
The structures of the sodium salts of two aromatic thiosulfonates
reported herein have revealed several features that should stimulate
further interest in this family of compounds: (1) unexpected
coordination of the pendant sulfur atom to sodium in preference
to oxygen in the p-tolyl derivative directed by CH/p interactions;
(2) formation of layer structure by the hydrated phenyl derivative
which is stabilised by hydrogen-bonding interactions within the
hydrophilic layer formed by the sodium ions, water ligands and
Empirical formula
FW (g mol-1)
T/K
C7H7NaO2S2
210.24
123(2)
Monoclinic
C2/m
7.2976(5)
9.6537(7)
12.7994(10)
94.058(4)
899.44(11)
4
1.553
0.591
8368
1456
1.24
0.0352, 0.0726
0.495, -0.340
C6H8NaO3.5S2
223.23
273(2)
Monoclinic
C2/c
26.688(3)
6.4934(8)
11.1130(13)
103.873(7)
1869.7(4)
8
1.586
0.585
8493
2632
1.16
0.0411, 0.0731
0.429, -0.396
Crystal system
Space group
˚
a/A
˚
b/A
˚
c/A
b (◦)
-
-S2O2 units and intermolecular CH/p interactions between the
3
˚
V/A
layers in addition to Na–O–Na bridges formed the water and
thiosulfate oxygens. In addition, pulse radiolysis studies indicate
reactivity differences in that the oxidation of aliphatic thiosul-
fonates involves formation of sulfur centred radicals whereas for
the aromatic analogues, organic radicals are generated.
Z
rc/g cm-3
m Mo-Ka (mm-1)
No. reflections collected
No. independent reflections
GOF on F2
R1,a wR2b [I > 2s(I)]
Maximum difference peak,
Experimental
-3
˚
hole/e A
1
2
a R1 = RꢁFo| - |Fcꢁ/R|Fo|; b wR2 = [Rw(Fo - Fc2)2/Rw(Fo ) ]
2
2 2
Materials
All inorganic salts, reagents and organic solvents were obtained
from commercial suppliers and used as received. Compounds used
for pulse radiolysis experiments were of analytical grade; other
compounds were of at least reagent grade. Distilled water was
boiled under nitrogen for at least one hour, and allowed to cool to
room temperature under nitrogen. This procedure produced water
with very low levels of CO2 and O2, and as such was suitable for
kinetics work requiring low levels of these dissolved gases.
to the solution. The mixture was heated at reflux with vigorous
stirring for 15 min, and then allowed to cool overnight. Large
yellow needles crystallised (unreacted elemental sulfur), which
were removed by filtration through a glass fibre filter (GF-A).
After filtration, the solvent was removed by rotary evaporation,
and the off-white solid residue was recrystallised from hot EtOH
(96%, ~60 mL) to yield NaMeS2O2·H2O as white crystals. Yield:
10.8 g (73%).
Instrumentation
Characterisation. Microanalyses: Found (%): C, 7.9; H, 3.3.
Calculated for CH5NaO3S2 (%): C, 7.9; H, 3.3. H-NMR (D2O)
1
IR spectra were recorded using either a Perkin-Elmer 1600 FTIR
or a Bruker Equinox IFS 55 FTIR as KBr disks to a resolution
of 4 cm-1. A Bruker Equinox IFS 55 FTIR fitted with a Specac
Goldengate ATR stage was used for recording ATR-IR spectra.
Elemental analyses were performed by Campbell Microanalytical
Services, University of Otago, Dunedin, New Zealand.
d (ppm): 3.36 (s, -CH3); lit.52 3.30 (s). Selected IR bands [KBr, n
(cm-1)]: 3420 (br), 3004 (m), 2916 (m), 1628 (m), 1420 (m), 1324
(m), 1198 (s), 1100 (s), 977 (s), 769 (s), 597 (s), 494 (s); lit.52 1320,
1220–1180 (br), 1100–1075 (br), 975, 770. UV spectrum (H2O)
[lmax, nm (emax, M-1 cm-1)]: 201 (3500).
NaPhS2O2. The synthesis was based on a literature method53
for p-toluenethiosulfonate. Sodium benzenesulfinate (0.996 g, 6.00
mmol) was dissolved in 30 mL of a 1 : 1 EtOH/H2O mixture.
Elemental sulfur (flowers of sulfur, 0.203 g, 6.33 mmol) was
added to the solution, which was then heated at reflux for four
days with vigorous stirring. After allowing the solution to cool,
it was filtered to remove unreacted sulfur, and the solvent was
removed by rotary evaporation to yield an off-white solid. The
solid residue was recrystallised from hot EtOH, and fine white
crystals were obtained after storage overnight at -20 ◦C. Yield:
0.42 g (36%). Slow evaporation of a 96% EtOH solution containing
this compound yielded crystals suitable for X-ray crystallography.
Characterisation. Microanalyses: Found (%): C, 36.9; H, 2.6.
Calculated for C6H5NaO2S2 (%): C, 36.7; H, 2.6. Selected IR bands
[KBr, n (cm-1)]: 3483 (s), 3409 (s), 3061 (m), 1608 (m), 1476 (w),
1444 (m), 1225 (s), 1192 (s), 1121 (s), 1067 (s), 760 (m), 721 (s),
688 (s), 629 (s), 545 (s), 424 (m); lit.51 n(S O), 1220, 1120, 1070
and;48 n(C C) 1445, 1310; n(S O), 1190, 1117, 1063; 1020, 1000;
X-Ray crystallography
Single crystal X-ray crystallography was performed on either an
Enraf-Nonius CAD4 diffractometer or a Bruker X8 Apex diffrac-
tometer with monochromated Mo-Ka radiation (l = 0.71073 A)
˚
at 123(2) K using j and/or w scans. Data were corrected for
Lorentz and polarisation effects, and absorption corrections were
applied using SADABS.84 The structures were solved by the direct
methods or Patterson maps and refined using the full-matrix least-
squares method of the programs SHELXS-9785 and SHELXL-
97,54 respectively. The program X-Seed86 was used as an interface
to the SHELX programs and to prepare the figures. Generally,
the alkyl/aryl hydrogens were modelled in idealised geometries;
otherwise, they were located on Fourier difference maps and
refined isotropically. Crystal data are summarised in Table 7.
Synthesis
1
NaMeS2O2·H2O. The synthesis was based on the method of
Macke and Field.52 In a typical preparation, sodium methanesul-
finate (9.95 g, 97.4 mmol) was dissolved in 600 mL of MeOH.
Elemental sulfur (flowers of sulfur, 3.19 g, 99.5 mmol) was added
d(C–H oop) 724, 689. H-NMR (D2O) d (ppm): 7.92–7.96 (2H,
ortho ArH, m) and 7.53–7.61 (3H, meta & para ArH, m); lit.51
(d6-DMSO) 7.31–7.80 (5H, ArH, m). UV spectrum (H2O) [lmax
,
nm (emax, M-1 cm-1)]: 242 (2300).
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 12310–12319 | 12317
©

NaMeC6H4S2O2. This compound was prepared following a
modification of the method of Harmon and Field.53 Sodium p-
toluenesulfinate hydrate (5.35 g, 27.3 mmol) was dissolved in
150 mL of 1 : 1 EtOH/H2O, and elemental sulfur (flowers of
sulfur, 1.00 g, 31.2 mmol) was added to the solution. The solution
was stirred vigorously and heated under reflux for three days.
After allowing the reaction mixture to cool, it was filtered to
remove unreacted sulfur, and then the solvent was removed by
rotary evaporation. The off-white residue was recrystallised from
absolute EtOH, giving colourless crystals. Yield: 4.12 g (72%). A
colourless plate from the recrystallisation was suitable for X-ray
crystallography.
of NaMeC6H4S2O2, NaMeC6H4SO3, and NaMeS2O2·H2O (0.01
M) were prepared just prior to measurement. Samples were
prepared by mixing the appropriate volumes of the thiosulfonate
or sulfonate, perchlorate and thiocyanate stock solutions, using an
autopipette (See Table S1†).
Acknowledgements
We gratefully acknowledge financial support from the Australian
Postgraduate Award Scheme (A.J.F), and the Australian Institute
for Nuclear Science and Engineering (AINSE), and the very
valuable technical assistance provided by Dr David Jenkinson
and Dr David Webb from the Australian Radiation Protection
and Nuclear Safety Agency (ARPANSA) and Assoc. Prof. Ron
Cooper (University of Melbourne).
Characterisation. Microanalyses: Found (%): C, 40.3; H, 3.5.
Calculated for C7H7NaO2S2 (%): C, 40.0; H, 3.4. Selected IR bands
[KBr, n (cm-1)]: 3414 (br m), 3039 (m), 2919 (m), 1596 (m), 1494
(m), 1398 (m), 1190 (s), 1118 (s), 1064 (s), 1013 (m), 973 (m), 815
(m), 710 (m), 670 (s), 612 (s), 532 (s); lit.51 n(S O), 1190, 1120,
1
1070. H-NMR (D2O) d (ppm): 7.81 (2H, o-ArH, d, J = 6 Hz),
Notes and references
7.37 (2H, m-ArH, d, J = 6 Hz) (AA¢BB¢ system) and 2.41 (3H,
-ArCH3, s); lit.53 2.36 (3H, CH3, s), ArH peaks not reported and51
(d6-DMSO) 2.28 (3H, -ArCH3, s), 7.13 (2H, ArH, d, J = 8 Hz),
1 I. Petrikovics, L. Pei, W. D. McGuinn, E. P. Cannon and J. L. Way,
Fundam. Appl. Toxicol., 1994, 23, 70–75.
2 L. Frankenberg, Arch. Toxicol., 1980, 45, 315–323.
7.62 (2H, ArH, d, J = 8 Hz). UV spectrum (H2O) [lmax, nm (emax
,
3 A. M. Pruski and A. Fiala-M
4 D. Cavallini, C. de Marco and B. Mondovi, J. Biol. Chem., 1959, 234,
854–857.
e´dioni, J. Exp. Biol., 2003, 206, 2923–2930.
M-1 cm-1)]: 243 (6700).
5 B. So¨rbo, Biochim. Biophys. Acta, 1957, 24, 324–329.
6 N. K. Rosenberg, R. W. Lee and P. H. Yancey, J. Exp. Zool., Part A,
2006, 305A, 655–622.
7 S. I. Baskin, V. Prabhaharan, J. D. Bowman and M. J. Novak, J. Appl.
Toxicol., 2001, 20, S3–S5.
8 H. Janota and A. Zakrzewski, Polish J. Appl. Chem., 1991, 35, 265–271.
9 P. Ro¨mbke, H. Schmidbaur, S. Cronje and H. Raubenheimer, J. Mol.
Catal. A: Chem., 2004, 212, 35–42.
10 P. Ro¨mbke, A. Schier, F. Wiesbrock and H. Schmidbaur, Inorg. Chim.
Acta, 2003, 347, 123–128.
11 M. El-khateeb, A. Shaver and A.-M. Lebuis, J. Organomet. Chem.,
2001, 622, 293–296.
12 M. El-khateeb, B. Wolfsberger and W. A. Schenk, J. Organomet. Chem.,
2000, 612, 14–17.
13 A. Shaver and P.-Y. Plouffe, J. Am. Chem. Soc., 1991, 113, 7780–7782.
14 A. A. Dundorina and A. N. Sergeeva, Russ. J. Inorg. Chem., 1974, 19,
181–183.
15 H.-D. Stachel, E. Eckl, E. Immerz-Winkler, C. Kreiner, W. Weigand,
C. Robl, R. Wu¨nsch, S. Dick and N. Drescher, Helv. Chim. Acta, 2002,
85, 4453–4467.
16 W. Weigand and R. Wu¨nsch, Chem. Ber., 1996, 129, 1409–1419.
17 D. Strope and D. F. Shriver, Inorg. Chem., 1974, 13, 2652–2655.
18 B. P. Cleary, R. Lok and W. W. White, European Patent Application
1388536A1, 2004, pp. 13.
19 R. Lok and W. W. White, US Patent 5620841, 1997, pp. 9.
20 R. Lok and W. W. White, US Patent 5700631, 1997, pp. 9.
21 R. Lok, W. W. White and M. W. Marshall, US Patent 5939245, 1999,
pp. 9.
Pulse radiolysis studies.
Instrumentation. Pulse radiolysis experiments were conducted
using the 20 MW linear accelerator (linac) at ARPANSA
(Australian Radiation Protection and Nuclear Safety Agency)
in Yallambie, Melbourne. This radiation source is capable of
generating pulses of high-energy electrons (6–20 MeV); the typical
pulse duration was ~400 ns. The electron beam was focussed into
a flow-through quartz cuvette (path length 1 cm) at 90◦ to the
analysing light source, which was an Osram XBO 450 W Xe
arc lamp. The wavelength was selected using a Bausch & Lomb
monochromator (1200 groves mm-1). Light intensity data were
digitised with a CompuScope 250 data acquisition card, which was
interfaced to a PC running ELACC. Post-capture data processing
was carried out using IGOR Pro 4.0.2.1 (Wavemetrics) to convert
the intensity data to absorbance data and to analyse the rate
constants.
Calibration. The potassium thiocyanate dosimeter was used to
measure the dose per pulse. This consisted of irradiating a 0.1 M
solution of KSCN and measuring the maximum absorbance at 480
∑
-
nm just after the pulse. The thiocyanate radical dimer, (SCN)2
,
is the transient absorbing species with lmax at 480 nm (emax at
∑
480 nm = 7600 M-1 cm-1).66 The concentration of (SCN)2 thus
determined is equal to the concentration of HO∑ produced by the
radiolysis. The concentration of hydroxyl radicals is doubled in
N2O saturated solution. The results of at least 10 pulses were used
to determine the dose (Gy/pulse).
-
22 A. J. Fischmann, A. C. Warden, J. Black and L. Spiccia, Inorg. Chem.,
2004, 43, 6568–6578.
23 A. J. Fischmann, C. M. Forsyth and L. Spiccia, Inorg. Chem., 2008, 47,
10565–10574.
24 A. J. Fischmann and L. Spiccia, Dalton Trans., 2011, 40, 4803–4805.
25 O. Foss and E. H. Vihovde, Acta Chem. Scand., 1954, 8, 1032–1041.
Solution preparation. All solutions were freshly prepared using
distilled water that had been purged of oxygen and carbon
dioxide by boiling under N2, other than the KSCN standard for
dosimetry which was supplied by ARPANSA. Each sample was
saturated with N2O by bubbling for five minutes just prior to the
pulse radiolysis experiments being carried out. Stock solutions
of perchlorate and thiocyanate (0.1 and 0.2 M, respectively)
were prepared from NaClO4·H2O and NaSCN, and the pH of
each was adjusted to 9.5 using NaOH solution. Stock solutions
¨
26 O. Foss and P. Oyum, Acta Chem. Scand., 1955, 9, 1014–1016.
¨
27 P. Oyum and O. Foss, Acta Chem. Scand., 1955, 9, 1012–1014.
28 O. Foss, Acta Chem. Scand., 1956, 10, 868–869.
29 O. Foss, Acta Chem. Scand., 1957, 11, 1442–1443.
30 O. Foss and A. Hordvik, Acta Chem. Scand., 1957, 11, 1443–1444.
31 O. Foss and I.-J. Johannessen, Acta Chem. Scand., 1961, 15, 1943–1945.
32 O. Foss, K. Marøy and S. Husebye, Acta Chem. Scand., 1965, 19, 2361–
2368.
33 O. Foss and A. Hordvik, Acta Chem. Scand., 1964, 18, 619–626.
34 O. Foss, N. Lyssandtræ, K. Maartmann-Moe and M. Tysseland, Acta
Chem. Scand., 1973, 27, 218–228.
12318 | Dalton Trans., 2011, 40, 12310–12319
This journal is
The Royal Society of Chemistry 2011
©

35 G. K. Cooper, D. P. Bloxham and M. Webster, J. Chem. Res., 1982,
1164–1172 (M).
63 R. Cervini, G. D. Fallon and L. Spiccia, Inorg. Chem., 1991, 30, 831–
836.
˚
36 K. Ase, Acta Chem. Scand., 1969, 23, 3206–3216.
64 S. J. Crimp, G. D. Fallon and L. Spiccia, J. Chem. Soc., Chem. Commun.,
˚
37 K. Ase, K. Maartmann-Moe and J. O. Solheim, Acta Chem. Scand.,
1992, 197–198.
1971, 25, 2467–2475.
65 S. Rudershausen and H. Reinke, Private Communication to CSD, 1999.
66 Y. Tabata, ed. Y. Tabata, Y. Ito and S. Tagawa, CRC Handbook of
Radiation Chemistry, Boca Raton, 1991, p. 937.
67 G. V. Buxton, C. L. Greenstock, W. P. Helman and A. B. Ross, J. Phys.
Chem. Ref. Data, 1988, 17, 513–886.
68 B. H. Milosavljevic and J. A. LaVerne, J. Phys. Chem. A, 2005, 109,
165–168.
69 P. J. Milne, R. G. Zika and E. S. Saltzman, in Biogenic Sulfur in the
Environment, ed. E. S. Saltzman and W. J. Cooper, ACS, Washington,
1989, pp. 518–528.
˚
38 K. Ase and I. Roti, Acta Chem. Scand., Ser. A, 1974, 28a, 104–112.
˚
39 K. Ase, Acta Chem. Scand., 1971, 25, 838–846.
40 M. Scho¨nesho¨fer, Int. J. Radiat. Phys. Chem., 1973, 5, 375–386.
41 R. Mehnert, O. Brede and I. Janovsky, Radiochem. Radioanal. Letters,
1982, 53, 299–309.
42 R. Mehnert and O. Brede, Radiat. Phys. Chem., 1984, 23, 463–468.
43 B. Goyal, S. Solanki, S. Arora, A. Prakash and R. N. Mehrotra, J.
Chem. Soc., Dalton Trans., 1995, 3109–3112.
44 A. Dutta, M. Ali, S. Gangopadhyay and P. Banerjee, Int. J. Chem.
Kinet., 1995, 27, 649–656.
45 K. K. Sen Gupta, S. Das and S. Sen Gupta, Transition Met. Chem.,
1988, 13, 155–159.
70 G. E. Adams, J. W. Boag, J. Currant and B. D. Michael, in Pulse
Radiolysis, ed. M. Ebert, J. P. Keene and A. J. Swallow, Academic
Press, London, 1965, pp. 131–143.
46 A. Panja, N. Shaikh, P. Banerjee and B. Saha, Int. J. Chem. Kinet.,
2003, 36, 119–128.
47 W. K. Wilmarth, D. M. Stanbury, J. E. Byrd, H. N. Po and C.-P. Chua,
Coord. Chem. Rev., 1983, 51, 155–179.
48 R. Mintel and J. Westley, J. Biol. Chem., 1966, 241, 3381–3385.
49 N. S. Zefirov, N. V. Zyk, E. K. Beloglazkina and A. G. Kutateladze, J.
Sulfur Chem., 1993, 14, 223–244.
50 J. Troeger and O. Linde, Arch. Pharm., 1901, 239, 121–145.
51 R. Sato, T. Goto, Y. Takikawa and S. Takizawa, Synthesis, 1980, 615.
52 J. D. Macke and L. Field, J. Org. Chem., 1988, 53, 396–402.
53 J. P. Harmon and L. Field, J. Org. Chem., 1986, 51, 5235–5240.
54 G. M. Sheldrick, SHELXL-97, University of Go¨ttingen, Germany,
1997.
71 L. M. Dorfman and G. E. Adams, Reactivity of the Hydroxyl Radical
in Aqueous Solution, US National Bureau of Standards, Washington,
1973.
72 R. Sarala and D. M. Stanbury, Inorg. Chem., 1992, 31, 2771–2777.
73 P. Y. Bruice, Organic Chemistry, Prentice-Hall, London, 1998.
74 T. M. Olson and R. W. Fessenden, J. Phys. Chem., 1992, 96, 3317–
3320.
75 G. C. Stevens, R. M. Clarke and E. J. Hart, J. Phys. Chem., 1972, 76,
3863–3867.
76 P. Neta and R. H. Schuler, J. Phys. Chem., 1975, 79, 1–6.
77 Z. M. Hoffman and E. Hayon, J. Phys. Chem., 1973, 77, 990–
996.
78 G. R. Dey, D. B. Naik, K. Kishore and P. N. Moorthy, Radiat. Phys.
55 M. Fleck and L. Bohaty´, Acta Crystallogr., Sect. C: Cryst. Struct.
Commun., 2005, 62, m22–m26.
56 M. Nishio, CrystEngComm, 2004, 6, 130–158.
57 H. Suezawa, T. Yoshida, Y. Umezawa, S. Tsuboyama and M. Nishio,
Eur. J. Inorg. Chem., 2002, 3148–3155.
Chem., 1999, 54, 19–27.
79 S. Gordon, K. H. Schmidt and E. J. Hart, J. Phys. Chem., 1977, 81,
104–109.
80 M. Roder, L. Wojna´rovits and Fo¨ldia´k, Radiat. Phys. Chem., 1990, 36,
175–176.
58 Y. Umezawa, S. Tsuboyama, H. Takahashi, J. Uzawa and M. Nishio,
Tetrahedron, 1999, 55, 10047–10056.
59 G. A. Jeffrey, An Introduction to Hydrogen Bonding, Oxford University
Press, New York, 1997.
81 L. M. Dorfman, I. A. Taub and R. E. Bu¨hler, J. Chem. Phys., 1962, 36,
3051–3061.
82 L. M. Dorfman, I. A. Taub and D. A. Harter, J. Chem. Phys., 1964,
41, 2954–2955.
60 F. H. Allen, C. M. Bird, R. S. Rowland and P. R. Raithby, Acta
Crystallogr., Sect. B: Struct. Sci., 1997, 53, 680–695.
61 M. M. Morlok, K. E. Janak, G. Zhu, D. A. Quarless and G. Parkin, J.
Am. Chem. Soc., 2005, 127, 14039–14050.
62 L. Spiccia, H. Stoeckli-Evans, M. Werner and R. Giovanoli, Inorg.
Chem., 1987, 26, 474–482.
83 R. F. Anderson, K. B. Patel and M. R. L. Stratford, J. Biol. Chem.,
1990, 265, 1952–1957.
84 G. M. Sheldrick, SADABS, University of Go¨ttingen, Germany, 1996.
85 G. M. Sheldrick, SHELXS-97, University of Go¨ttingen, Germany,
1997.
86 L. J. Barbour, J. Supramol. Chem., 2001, 1, 189–191.
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 12310–12319 | 12319
©