Metallosupramolecular silver complexes of bis- and tetrakis-(2-pyridylsulfanylmethyl)benzenes

Article abstract of DOI:10.1039/a807398h

The three isomeric bis(2-pyridylsulfanylmethyl)benzenes and 1,2,4,5-tetrakis(2-pyridylsulfanylmethyl)benzene have been prepared by reactions of pyridine-2-thiol with the appropriate poly(bromomethyl)benzene, in the presence of triethylamine, in good yields. Each of these new ligands reacts with silver nitrate, in excellent yield, to give co-ordination complexes in which the ligands bridge two or more metal centres. The crystal structures of these complexes have been determined. The para-disubstituted isomer self-assembles into a M₂L₂ macrocyclic dimer. The other ligands form one-dimensional metallopolymers containing complex networks of interconnected macrocyclic rings. In the crystal packings π-π stacking interactions between aromatic rings are observed.

Full text of DOI:10.1039/a807398h

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Metallosupramolecular silver complexes of bis- and tetrakis-
(2-pyridylsulfanylmethyl)benzenes
Chris M. Hartshorn and Peter J. Steel*
Chemistry Department, University of Canterbury, Christchurch, New Zealand.
E-mail: p.steel@chem.canterbury.ac.nz
Received 22nd September 1998, Accepted 24th September 1998
The three isomeric bis(2-pyridylsulfanylmethyl)benzenes and 1,2,4,5-tetrakis(2-pyridylsulfanylmethyl)benzene
have been prepared by reactions of pyridine-2-thiol with the appropriate poly(bromomethyl)benzene, in the
presence of triethylamine, in good yields. Each of these new ligands reacts with silver nitrate, in excellent yield, to
give co-ordination complexes in which the ligands bridge two or more metal centres. The crystal structures of these
complexes have been determined. The para-disubstituted isomer self-assembles into a M2L2 macrocyclic dimer. The
other ligands form one-dimensional metallopolymers containing complex networks of interconnected macrocyclic
rings. In the crystal packings π–π stacking interactions between aromatic rings are observed.
recently been shown to self-assemble into aggregated metallo-
Introduction
supramolecular boxes in the presence of silver() ions, with co-
ordination by all N and S donors.11 Furthermore, we have
recently shown that reaction of silver nitrate with di-2-pyridyl
sulfide, a ligand that normally acts as a N,N-bidentate chelating
ligand, results in the formation of a novel binuclear complex in
which the ligand co-ordinates in an N,N,S-tridentate bridging
mode to form a structure with the same topology as those of
the well studied organic photodimers of anthracene.12 The
study of such assembly processes can provide useful inform-
ation for use in the rapidly expanding area of crystal engineer-
ing.13 We now report the preparation of four new bridging
ligands that contain 2-pyridylsulfanyl groups attached to
xylylene cores, and the synthesis and crystal structures of their
respective complexes with silver() nitrate.
We are currently involved in the synthesis and study of a large
range of ligands represented by the generalised structure I, in
which various numbers of heterocyclic donors are attached
via spacer groups, X to a central arene core. For example, we
have reported the ability of polypyrazolylmethylbenzenes to
encapsulate metal ions,1 to form large metallosupramolecular
cages,2 to bridge metal–metal bonded species3 and to undergo
double cyclometallation reactions.4 We have also shown that
1,4-bis(2-pyridyloxy)benzene self-assembles in the presence of
silver nitrate into a M2L2 dimetalloparacyclophane 1 with
intimate π–π stacking of the central benzene rings.5 In the
accompanying paper we described experiments designed to
assess the factors controlling this self-assembly process.6 One
such factor that was considered was the possible role of the aryl
ether oxygen atoms.
Results and discussion
The three isomeric bis(2-pyridylsulfanylmethyl)benzenes
(II–IV) were prepared by adaptation of a literature procedure
for the preparation of benzyl 2-pyridyl sulfide.14 Reaction of
pyridine-2-thiol with the appropriate bis(bromomethyl)benz-
ene, in the presence of triethylamine, gave II–IV in good yields,
and the products were fully characterised by 1H and 13C NMR,
using a combination of 1-D and 2-D NMR techniques. Each of
these ligands reacted smoothly with one equivalent of silver
nitrate, in aqueous methanol, to give good yields of the corre-
sponding complexes 2–4. Crystals suitable for structure deter-
mination were obtained by slow evaporation of acetonitrile
solutions of these complexes.
X
N
n
I
N
O
O
O
O
N
Ag
N
Ag
N
¯
The complex 2 crystallises in the triclinic space group P1 and
is a centrosymmetric M2L2 dimetalloparacyclophane. Fig. 1
shows a perspective view of the structure, with atom labelling
of the asymmetric unit. Selected interatomic distances and
angles are also listed. Each silver atom is co-ordinated to two
pyridine nitrogens and an oxygen atom of the nitrate anion,
with all three silver–donor bond distances within the range
expected for such co-ordination.15 The distances between the
silver and the sulfur atoms of the ligand are greater than >3.16
Å, which in structurally related structures has been considered
non-interacting.16 The co-ordination geometry of the silver is
distorted T-shaped with the co-ordinated oxygen slightly dis-
placed towards one of the pyridines. The mean planes of the
pyridine rings are inclined at angles of 91.9(2) and 125.2(2)Њ to
1
We reasoned that incorporation of sulfur atoms in related
ligands would lead to greater chalcogen–metal interactions, as
a result of the high thiophilicity of the silver() ion. In contrast
to the extensive literature on the co-ordination chemistry of
heterocyclic thiolates,7 less attention has been paid to pyridyl
thioethers,8 even though thioethers are well established ligands
in co-ordination9 and metallosupramolecular chemistry.10 Lig-
ands containing pyridyl substituents directly linked to sulfide
spacer groups might be expected to form interesting complexes
with silver() ions. For example, a thiomethylterpyridine has
J. Chem. Soc., Dalton Trans., 1998, 3935–3940
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Fig. 2 Packing diagram of complex 2 showing π–π stacking inter-
actions between the pyridine rings of the macrocycles.
Fig. 1 Perspective view and atom labelling of the crystal structure of
complex 2. Selected interatomic distances (Å) and angles (Њ): Ag(1)–
N(11) 2.166(2), Ag(1)–N(41A) 2.165(2), Ag(1)–O(1) 2.592(2),
Ag(1) ؒ ؒ ؒ S(10) 3.160(1), Ag(1) ؒ ؒ ؒ S(40A) 3.164(1); N(11)–Ag(1)–
N(41A) 169.70(8), N(11)–Ag(1)–O(1) 98.36(8), N(41A)–Ag(1)–O(1)
91.60(8).
S
S
N
N
II
N
S
S
N
Fig. 3 Perspective view and atom labelling of the crystal structure of
complex 3. Selected interatomic distances (Å) and angles (Њ): Ag(1)–
N(11) 2.285(7), Ag(1)–N(31A) 2.327(6), Ag(1)–S(30A) 2.658(3), Ag(1)–
O(2) 2.418(7); N(11)–Ag(1)–N(31A) 119.9(3), N(11)–Ag(1)–S(30A)
118.5(2), N(11)–Ag(1)–O(2) 112.5(3), N(31A)–Ag(1)–S(30A) 106.6(2),
N(31A)–Ag(1)–O(2) 88.8(3), S(30A)–Ag(1)–O(2) 105.9(2).
III
N
N
S
S
IV
that of the linking benzene ring, while the two pyridine ring
mean planes at each silver atom are inclined to one another at
an angle of 57.0(2)Њ.
An important feature of this macrocycle is the absence of an
intramolecular π–π stacking interaction, as the two benzene
rings are significantly displaced from one another, in contrast
to the situation in complexes such as 1.5,6 Thus, such π–π
stacking is not a necessary feature for the formation of
these M2L2 macrocycles. Within the 26-membered macro-
cycle the Ag ؒ ؒ ؒ Ag separation is 12.196(2) Å, which is con-
siderably greater than the corresponding value [11.269(2) Å] in
the structure of a concave dipalladium complex of the same
ring size.6
Whilst there is an absence of intramolecular π–π stacking,
the packing of the macrocycles is controlled, in part, by such
interactions. As shown in Fig. 2, the dimetallomacrocycles self-
assemble into a two-dimensional array within which there is
π–π stacking between pyridine rings of adjacent macrocycles
(average plane-to-plane distance = 3.8 Å). As observed in other
cases,5,6 this stacking occurs with the aromatic rings disposed
such that an atom of one ring lies approximately over the
centroid of another ring.
Fig. 4 Perspective view (top), with hydrogens omitted, and schematic
representation (bottom) of a section of the extended polymeric
structure of complex 3. Nitrate anions are not shown.
from different ligands, as well as an oxygen from the nitrate
counter ion. The geometry of these four donors around the
silver is distorted tetrahedral [donor–Ag–donor angles between
88.8(3) and 119.9(3)Њ]. The distortion from tetrahedral geom-
etry is possibly due to an additional semi-co-ordinative inter-
action with a second sulfur atom [viz. S(10)]. The mean planes
of the pyridine rings are inclined at angles of 84.2(9) and
63.3(9)Њ to that of the linking benzene ring, while the two
pyridine ring mean planes are inclined to one another at an
angle of 62.1(9)Њ.
The silver complex 3 of the meta-disubstituted ligand III
¯
crystallises in the triclinic space group P1 and is a one dimen-
sional metallopolymer. Fig. 3 shows a perspective view and
atom labelling of the asymmetric unit of the structure, along
with selected interatomic distances and angles. The silver atom
is co-ordinated to two pyridine nitrogens and a sulfur, each
Co-ordination by the silver atom to donors from three differ-
ent ligands results in the assembly of an intriguing extended
polymeric structure. Fig. 4 shows a perspective view and
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Fig. 5 Perspective view and atom labelling of complex 4. Selected inter-
atomic distances (Å) and angles (Њ): Ag(1)–Ag(1A) 2.9874(5), Ag(1)–
N(11A) 2.288(2), Ag(1)–N(21A) 2.377(2), Ag(1)–S(10) 2.4984(8),
Ag(1)–O(2) 2.571(2); Ag(1A)–Ag(1)–N(11A) 90.79(6), Ag(1A)–Ag(1)–
N(21A) 117.51(6), Ag(1A)–Ag(1)–S(10) 78.35(2), Ag(1A)–Ag(1)–
O(2) 155.46(6), N(11A)–Ag(1)–N(21A) 103.82(8), N(11A)–Ag(1)–
S(10) 154.44(6), N(11A)–Ag(1)–O(2) 85.09(8), N(21A)–Ag(1)–S(10)
101.71(6), N(21A)–Ag(1)–O(2) 86.91(8), S(10)–Ag(1)–O(2) 95.21(5).
Fig. 6 Perspective view (top), with hydrogens omitted, and schematic
representation (bottom) of a section of the extended polymeric struture
of complex 4. The nitrate anions are not shown.
second silver and nitrate oxygen occupying the axial sites. The
mean planes of the pyridine rings are inclined at angles of
27.9(2) and 77.9(2)Њ to that of the linking benzene ring, while
the two pyridine ring mean planes are inclined to one another at
an angle of 62.7(2)Њ. The silver atom lies out of the extended
planes of the co-ordinated pyridine rings by 0.214(3) and
0.226(3) Å.
Fig. 6 shows a perspective view and a schematic represen-
tation of the extended polymeric structure of the complex 4,
which, like that of 3, consists of a complex system of inter-
connected rings. In both structures a binuclear bis(pyridyl
sulfide) moiety is present, and the pyridyl ring at the opposite
end of these ligands co-ordinates to a silver atom of the next
binuclear unit. However, there is a difference between the two
structures as to which silver of the binuclear pair is bonded
to the “bridging” pyridine. In 3 the “bridging” pyridine co-
ordinates to the closer silver of the next binuclear pair, while in
4 it co-ordinates to the more distant silver of the next pair. As a
result, the twenty-membered macrocycle linking two binuclear
units in 4 incorporates four silver atoms, with an Ag ؒ ؒ ؒ Ag
transannular interatomic distance of 8.138(1) Å. Once again,
π–π stacking interactions exist between pyridine rings of
adjacent chains, although in this case the separation between
the rings is somewhat greater (3.55 Å).
schematic representation of a section of the polymeric chain,
which consists of an alternating array of two different sizes of
macrocycle fused by a common bond. The smaller of the two is
a centrosymmetric eight-membered ring containing two silver
atoms [Ag ؒ ؒ ؒ Ag 4.340(2) Å], bridged by a pair of pyridyl
thioether moieties, with the two pyridine rings co-ordinated to
different silver atoms. This eight-membered ring adopts a chair
conformation with the two pyridine rings transoid with respect
to the Ag2S2 plane, as necessitated by the crystallographic
centre of inversion. Such a substructure is also present in the
silver nitrate complex of di-2-pyridyl sulfide.12
Fused to this macrocycle is a twenty-membered centro-
symmetric dinuclear ring. Again, the ring is formed by co-
ordination of a pyridine nitrogen and a sulfur atom to each
of two silver atoms. However, in this case, instead of the
co-ordinating sulfur bonding directly to the co-ordinating
pyridine, they are separated by the arene spacer of the ligand.
As a result, the macrocycle is enlarged to twenty members with
an Ag ؒ ؒ ؒ Ag interatomic distance of 7.920(2) Å.
While there are no π–π stacking interactions within this
polymer chain, inspection of the molecular packing reveals that
there does exist a series of such interactions between pyridine
rings of adjacent chains. Crystallographically related pyridine
rings are parallel stacked with a plane-to-plane separation of
only 3.18(1) Å. Once again, the arrangement of this stacking
is such that an atom of one ring lies over the centroid of the
adjacent ring. Similar intermolecular interactions have recently
been shown to exist between molecular squares derived from
silver nitrate and pyrimidine.17
The silver complex 4 of the ortho-disubstituted ligand IV
crystallises in the monoclinic space group P21/n and is also a
one dimensional metallopolymer. Fig. 5 shows a perspective
view of the labelled contents of the asymmetric unit and
selected interatomic distances and angles. The silver atom is co-
ordinated to two pyridine nitrogens and a sulfur atom, each
from different ligands, as well as to an oxygen from the nitrate
counter ion. The silver atom further interacts with a silver atom
related by a crystallographic centre of inversion [Ag–Ag dis-
tance 2.9874(5) Å]. Similar silver–silver interactions have been
observed in complexes of other nitrogen-containing hetero-
cyclic ligands.3,18 The geometry of the five atoms around the
silver is distorted trigonal bipyramidal, with the central silver,
sulfur and two nitrogens approximately coplanar and with the
The three isomeric bis(2-pyridylsulfanylmethyl)benzenes
II–IV react with silver nitrate to form a dimeric structure, for
the para isomer, and one-dimensional polymeric structures, for
the meta and ortho isomers. A ligand that incorporates all
three of these substitution patterns as subunits is the tetra-
podal ligand 1,2,4,5-tetrakis(2-pyridylsulfanylmethyl)benzene
V, which might also offer the possibility of forming metallo-
polymers of higher dimensionality. This new ligand was
synthesized in excellent yield from pyridine-2-thiol and 1,2,4,5-
tetrakis(bromomethyl)benzene (Scheme 1) and treated with two
equivalents of silver nitrate to give, in high yield, a complex 5,
the crystal structure of which was determined.
¯
The complex 5 crystallises in the triclinic space group P1 with
the asymmetric unit containing half a ligand, a silver nitrate
unit and a water molecule, and is another one-dimensional
polymer. Fig. 7 shows a perspective view and atom labelling of
the structure. To each silver atom is co-ordinated a chelated
pyridyl moiety and a pyridine nitrogen from a different ligand.
The nitrate counter ion and the water molecule are disordered,
approximately evenly, over two sites. For half of the silver
atoms, a water oxygen is also co-ordinated [Ag(1)–O(100)
J. Chem. Soc., Dalton Trans., 1998, 3935–3940
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Fig. 8 Perspective view of a section of the extended polymeric
structure of complex 5. The nitrate anions are not shown.
π–π interaction between the two co-ordinated pyridines
within the ring, the mean planes of which are separated by
3.34(1) Å. Weak π–π interactions exist between pyridine rings
of adjacent polymer chains, which also exhibit short S ؒ ؒ ؒ S
contacts [3.412(2) Å]. Such sulfur–sulfur interactions have
recently been shown to exist in other supramolecular silver
networks.19
Fig. 7 Perspective view and atom labelling of complex 5. Selected
interatomic distances (Å) and angles (Њ): Ag(1)–N(11) 2.271(3), Ag(1)–
N(31B) 2.227(3), Ag(1)–S(10) 2.956(1), Ag(1)–O(100) 2.360(8),
Ag(1) ؒ ؒ ؒ O(1A) 2.639(8), Ag(1) ؒ ؒ ؒ O(2A) 2.793(8); N(11)–Ag(1)–
N(31B) 145(1), N(11)–Ag(1)–S(10) 57.03(8), N(11)–Ag(1)–O(100)
91.0(2), N(31B)–Ag(1)–S(10) 88.80(8), N(31B)–Ag(1)–O(100) 119.5(2),
S(10)–Ag(1)–O(100) 133.4(2).
Conclusion
Reaction of silver nitrate with each of the four new ligands
described above results in the assembly of co-ordination com-
plexes within which the ligands bridge two or more metal
centres. In general, co-ordination of the ligand nitrogen and
sulfur donors results in the formation of extended one-
dimensional polymeric structures containing a complex system
of interconnected metallomacrocyclic rings. The nature of
co-ordination complexes formed from these and related
ligands appears to result from a delicate interplay of thermo-
dynamic and kinetic factors, which are now recognised to
control the self-assembly of various metallosupramolecular
architectures.20
BrH2C
BrH2C
CH2Br
CH2Br
Et3N
CH3CN
N
SH
Experimental
General
General experimental details are given in the accompanying
paper.6 The isomeric bis(bromomethyl)benzenes21 and 1,2,4,5-
tetrakis(bromomethyl)benzene22 were prepared by literature
procedures.
N
N
N
N
S
S
S
S
Ligand preparations
1,4-Bis(2-pyridylsulfanylmethyl)benzene II. 1,4-Bis(bromo-
methyl)benzene (0.59 g, 2.24 mmol) was added, with stirring, to
an ice-cooled solution of pyridine-2-thiol (0.50 g, 4.48 mmol)
and triethylamine (0.57 g, 5.6 mmol) in acetonitrile (10 ml). The
mixture was stirred for 24 h at room temperature, filtered and
concentrated to give a yellow residue that was dissolved in
chloroform (15 ml). This solution was washed with water
(2 × 30 ml), dried (Na2SO4), and concentrated to give crude
compound II as a white solid. Recrystallisation from light
petroleum (bp 40–60 ЊC) gave pure II (0.40 g, 55%), mp 76 ЊC
(Found: C, 66.26; H, 4.90; N, 8.71. C9H8NS requires C, 66.63;
H, 4.97; N, 8.63%). 1H NMR (CDCl3): δ 4.41 (4 H, s, CH2), 6.98
(2 H, t, H5Ј), 7.15 (2 H, d, H3Ј), 7.33 (4 H, s, H2,3,5,6), 7.46
(2 H, t, H4Ј), 8.45 (2 H, d, H6Ј). 13C NMR (CDCl3): δ 33.92
(CH2), 119.44 (C3Ј), 121.92 (C5Ј), 128.96 (C2,3,5,6), 135.82
(C4Ј), 136.71 (C1,4), 149.23 (C6Ј), 158.59 (C2Ј).
V
5
2 AgNO3
Scheme 1
2.360(8) Å], and for the other half two nitrate oxygens are
weakly co-ordinated to the silver [Ag(1) ؒ ؒ ؒ O(1A) 2.639(9),
Ag(1) ؒ ؒ ؒ O(2A) 2.793(9) Å]. The mean planes of the pyridine
rings are inclined at angles of 87.1(8) and 94.7(8)Њ to that of the
linking benzene ring, and at 7.9(8)Њ to each other.
Despite the fact that the ligand V is co-ordinated to four
different silver atoms, the complex is still a one-dimensional
polymer, a section of which is shown in Fig. 8. The polymeric
structure is a chain of twenty-membered macrocycles joined by
benzene rings which are shared by adjacent macrocycles.
The Ag ؒ ؒ ؒ Ag separation [7.447(1) Å] across the macrocycles
is shorter than those of the previously described twenty-
membered binuclear rings, possibly as a consequence of a
1,3-Bis(2-pyridylsulfanylmethyl)benzene III. Reaction of 1,3-
bis(bromomethyl)benzene (0.59 g, 2.24 mmol) with pyridine-2-
thiol (0.50 g, 4.48 mmol) and triethylamine (0.57 g, 5.6 mmol),
as described above for II, gave compound III as a yellow oil
ϩ
(0.61 g, 84%) (Found: M ϩ, 324.0755. C18H16N2S2 requires M
᝽
᝽
324.0755). 1H NMR (CDCl3): δ 4.40 (4 H, s, CH2), 6.98 (2 H, t,
H5Ј), 7.14 (2 H, d, H3Ј), 7.22 (1 H, t, H5), 7.28 (2 H, d, H4,6),
7.45 (3 H, H2,4Ј), 8.44 (2 H, d, H6Ј). 13C NMR (CDCl3): δ 34.06
3938
J. Chem. Soc., Dalton Trans., 1998, 3935–3940

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Table 1 Crystal data and details of data collections and structure refinements for complexes 2–5
2
3
4
5
Formula
C36H32Ag2N6O6S4
988.66
Triclinic
C18H16AgN3O3S2
494.33
Triclinic
C18H16AgN3O3S2
494.33
Monoclinic
8.556(1)
C30H30Ag2N6O8S4
946.58
Triclinic
Formula weight
Crystal system
a/Å
7.803(2)
8.281(3)
9.360(1)
b/Å
c/Å
α/Њ
β/Њ
10.173(1)
13.206(2)
104.39(1)
103.84(2)
104.66(1)
929.9(3)
P1
1
1.77
496
10.011(3)
11.488(4)
106.16(2)
97.04(3)
10.617(1)
19.827(2)
9.712(1)
10.042(1)
92.42(1)
100.10(1)
109.98(1)
839.5(2)
¯
P1
1
1.87
474
97.25(1)
γ/Њ
91.75(3)
V/Å3
905.8(5)
1786.7(3)
P21/n
4
1.84
992
¯
¯
Space group
Z
P1
2
1.81
496
Dc/Mg mϪ3
F(000)
T/K
168(2)
158(2)
169(2)
169(2)
Crystal form
Crystal size/mm
µ/mmϪ1
Colourless block
0.26 × 0.21 × 0.13
1.33
Colourless plate
0.54 × 0.52 × 0.12
1.37
Colourless block
0.64 × 0.46 × 0.27
1.39
Colourless block
0.42 × 0.31 × 0.21
1.48
2θ range/Њ
Reflections collected
Unique reflections (Rint
Parameters
Difference peaks/e ÅϪ3
Goodness of fit
Ra [I > 2σ(I)]
wRb (all data)
4–55
4509
4194 (0.018)
244
0.553
0.903
0.0301
0.0598
4–50
3393
3152 (0.242)
244
2.901
0.966
0.0795
0.2145
4–50
3384
3153 (0.022)
244
1.836
1.027
0.0253
0.0643
4–50
3148
2944 (0.022)
272
0.696
0.876
0.0320
0.0658
)
¹
2
a R = Σ(|Fo| Ϫ |Fc|)/Σ|Fo|. b wR = [Σw(Fo2 Ϫ Fc2)2]/Σw(Fo )2]².
(CH2), 119.36 (C3Ј), 121.74 (C5Ј), 127.46 (C4,6), 128.36 (C5),
129.29 (C2), 135.77 (C4Ј), 137.81 (C1,3), 149.04 (C6Ј), 158.36
(C2Ј).
white precipitate (98 mg, 83%), mp 151–152 ЊC (Found: C,
43.64; H, 3.26; N, 8.57. C18H16AgN3O3S2 requires C, 43.73; H,
3.26; N, 8.50%).
[Ag(IV)(NO3)]n 4. Reaction of compound IV (82 mg, 0.25
mmol), dissolved in hot methanol (10 ml), with silver nitrate
(43 mg, 0.25 mmol), dissolved in hot methanol (5 ml), gave a
colourless solution that was filtered. Diethyl ether was diffused
into this solution to give complex 4 as a white solid (86 mg,
71%), mp 152–153 ЊC (Found: C, 43.51; H, 3.33; N, 8.59.
C18H16AgN3O3S2 requires C, 43.73; H, 3.26; N, 8.50%).
1,2-Bis(2-pyridylsulfanylmethyl)benzene IV. Reaction of 1,2-
bis(bromomethyl)benzene (0.59 g, 2.24 mmol) with pyridine-2-
thiol (0.50 g, 4.48 mmol) and triethylamine (0.57 g, 5.6 mmol),
as described above for II, gave compound IV as a yellow solid
that was recrystallised from light petroleum (0.61 g, 84%), mp
82 ЊC (Found: C, 66.42; H, 5.27; N, 8.61%). 1H NMR (CDCl3):
δ 4.61 (4 H, s, CH2), 6.96 (2 H, t, H5Ј), 7.15 (2 H, d, H3Ј), 7.19
(2 H, dd, H4,5), 7.43 (2 H, dd, H3,6), 7.45 (2 H, t, H4Ј), 8.42
(2 H, d, H6Ј). 13C NMR (CDCl3): δ 31.71 (CH2), 119.41 (C3Ј),
121.93 (C5Ј), 127.53 (C3,6), 130.46 (C4,5), 135.80 (C4Ј), 136.18
(C1,2), 149.24 (C6Ј), 158.70 (C2Ј).
[Ag(NO3)]2(V)ؒ2H2O 5. Reaction of compound V (70 mg,
0.12 mmol), dissolved in hot acetone (10 ml), with silver nitrate
(42 mg, 0.24 mmol), dissolved in water (4 ml), gave complex 5 as
a white precipitate (98 mg, 86%), mp 153–154 ЊC (Found: C,
38.24; H, 3.18; N, 8.94. C30H26Ag2N6O6S4ؒ2H2O requires C,
38.07; H, 3.19; N, 8.88%).
1,2,4,5-Tetrakis(2-pyridylsulfanylmethyl)benzene V. Reaction
of 1,2,4,5-tetra(bromomethyl)benzene (0.50 g, 1.11 mmol) with
pyridine-2-thiol (0.50 g, 4.44 mmol) and triethylamine (0.57 g,
5.6 mmol), as described above for II, gave a precipitate of
compound V directly from the reaction mixture. This was fil-
tered off, washed with water (3 × 10 ml) and recrystallised from
acetonitrile to give pure V (0.52 g, 82%), mp 114 ЊC (Found: C,
62.84; H, 4.79; N, 9.98. C15H13N2S2 requires C, 63.12; H, 4.59;
N, 9.82%). 1H NMR (CDCl3): δ 4.52 (8 H, s, CH2), 6.95, (4 H,
t, H5Ј), 7.12 (4 H, d, H3Ј), 7.44 (4 H, t, H4Ј), 7.48 (2 H, s, H3,6),
8.38 (4 H, d, H6Ј). 13C NMR (CDCl3): δ 31.38 (CH2), 119.40
(C3Ј), 121.95 (C5Ј), 132.75 (C3,6), 135.41 (C1,2,4,5), 135.79
(C4Ј), 149.23 (C6Ј), 158.62 (C2Ј).
X-Ray crystallography
The crystal data and details of the data collections and refine-
ments for the four structures are listed in Table 1. All measure-
ments were made with a Nicolet P4s diffractometer using
graphite-monochromatized Mo-Kα (λ = 0.71073 Å) radiation.
Cell parameters were determined by least-squares refinement
on diffractometer angles for at least 20 accurately centred reflec-
tions. Throughout data collections (ω scan mode) the intensities
of three standard reflections were monitored at regular inter-
vals and in no case showed variations of >5%. Intensities were
corrected for Lorentz-polarisation effects and for minor
absorption using a technique based on azimuthal ψ scans.
The structures were solved by direct methods using
SHELXS23 and refined on F2 using all data by full-matrix
least-squares procedures with SHELXL 93.24 All non-hydrogen
atoms were refined with anisotropic displacement parameters.
Hydrogen atoms were included in calculated positions with
isotropic displacement parameters 1.3 times the isotropic
equivalent of their carrier atoms. The functions minimised
Silver nitrate complexes
[Ag(II)(NO3)]2 2. Reaction of compound II (71 mg, 0.22
mmol), dissolved in hot methanol (12 ml), with silver nitrate (37
mg, 0.22 mmol), dissolved in water (3 ml), gave complex 2 as a
white precipitate (73 mg, 68%), mp >162 ЊC (decomp.) (Found:
C, 43.60; H, 3.42; N, 8.37. C18H16AgN3O3S2 requires C, 43.73;
H, 3.26; N, 8.50%).
2
[Ag(III)(NO3)]n 3. Reaction of compound III (79 mg, 0.24
mmol), dissolved in methanol (10 ml), with silver nitrate (41
mg, 0.24 mmol), dissolved in water (3 ml), gave complex 3 as a
were Σw(Fo2 Ϫ Fc2), with w = [σ2(Fo ) ϩ aP2 ϩ bP]Ϫ1, where P =
[max(Fo)2 ϩ 2Fc2]/3.
CCDC reference number 186/1179.
J. Chem. Soc., Dalton Trans., 1998, 3935–3940
3939

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