Di- and tetranuclear silver (I)-saccharinate complexes with 2-pyridineethanol and 2-pyridinepropanol: Syntheses, crystal structures, spectroscopic and thermal analyses of [Ag2(sac)2(pyet) 2] and [Ag4(sac)4(pypr)2]

Article abstract of DOI:10.1016/j.poly.2005.01.006

Two new (saccharinato)silver (I) complexes, [Ag₂(sac) ₂(pyet)₂] and [Ag₄(sac)₄(pypr) ₂] (sac = saccharinate, pyet = 2-pyridineethanol and pypr = 2-pyridinepropanol), have been prepared and characterized by elemental analyses, IR, thermal analysis and single crystal X-ray diffraction. Both complexes crystallize in triclinic space group of P1?. In [Ag₂(sac) ₂(pyet)₂], two monomeric [Ag(sac)₂(pyet)] units are doubly bridged by the sulfonyl oxygen atoms of the sac ligands, forming an [Ag₂(sac)₂(pyet)₂] dimer, in which each silver (I) centre is three coordinate with a T-shaped coordination and the Ag-Ag separation is 5.205 ?. The dimeric units are connected by strong O-H?O_sulfonyl intermolecular hydrogen bonds into a one-dimensional chain running parallel to b. The one-dimensional hydrogen bonded chains are further linked by π(sac)-π(pyet) stacking interactions. The tetranuclear complex, [Ag₄(sac)₄(pypr)₂], is achieved by bridging of [Ag₂(sac)₂] with two [Ag(sac)(pypr)] units through the sulfonyl oxygen atoms of the sac ligands. The two silver (I) ions in the centre with a short Ag-Ag bond distance of 2.8480(13) ? exhibit a T-shaped geometry with three sac ligands, while the two terminal silver (I) ions are coordinated by a sac ligand and a pypr ligand in a near linear geometry. The tetranuclear units are held together by O-H?O and C-H?O hydrogen bonds.

Full text of DOI:10.1016/j.poly.2005.01.006

Polyhedron 24 (2005) 693–699
www.elsevier.com/locate/poly
Di- and tetranuclear silver (I)-saccharinate complexes with
-pyridineethanol and 2-pyridinepropanol: Syntheses,
2
crystal structures, spectroscopic and thermal analyses
of [Ag (sac) (pyet) ] and [Ag (sac) (pypr) ]
2
2
2
4
4
2
a,
Veysel T. Yilmaz , Sevim Hamamci , William T.A. Harrison , Carsten Th o¨ ne
a
b
c
*
a
Department of Chemistry, Faculty of Arts and Sciences, Ondokuz Mayis University, 55139 Kurupelit, Samsun, Turkey
b
Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland, UK
Institut f u¨ r Anorganische und Analytische Chemie, Technische Universitat Braunschweig, Postfach 3329, 38023 Braunschweig, Germany
c
Received 20 December 2004; accepted 31 January 2005
Abstract
2 2 2 4 4 2
Two new (saccharinato)silver (I) complexes, [Ag (sac) (pyet) ] and [Ag (sac) (pypr) ] (sac = saccharinate, pyet = 2-pyridineeth-
anol and pypr = 2-pyridinepropanol), have been prepared and characterized by elemental analyses, IR, thermal analysis and single
ꢀ
crystal X-ray diffraction. Both complexes crystallize in triclinic space group of P1. In [Ag
pyet)] units are doubly bridged by the sulfonyl oxygen atoms of the sac ligands, forming an [Ag
silver (I) centre is three coordinate with a T-shaped coordination and the AgÁ Á ÁAg separation is 5.205 A. The dimeric units are
connected by strong O–HÁ Á ÁO intermolecular hydrogen bonds into a one-dimensional chain running parallel to b. The
2
(sac)
2
(pyet)
2
], two monomeric [Ag(sac)
2
-
(
2
(sac)
2
(pyet) ] dimer, in which each
2
˚
sulfonyl
one-dimensional hydrogen bonded chains are further linked by p(sac)–p(pyet) stacking interactions. The tetranuclear complex,
Ag (sac) (pypr) ], is achieved by bridging of [Ag (sac) ] with two [Ag(sac)(pypr)] units through the sulfonyl oxygen atoms of the
[
4
4
2
2
2
˚
sac ligands. The two silver (I) ions in the centre with a short Ag–Ag bond distance of 2.8480(13) A exhibit a T-shaped geometry
with three sac ligands, while the two terminal silver (I) ions are coordinated by a sac ligand and a pypr ligand in a near linear geom-
etry. The tetranuclear units are held together by O–HÁ Á ÁO and C–HÁ Á ÁO hydrogen bonds.
Ó 2005 Elsevier Ltd. All rights reserved.
Keywords: Saccharinate; 2-Pyridineethanol; 2-Pyridinepropanol; Dinuclear and tetranuclear silver (I)
1
. Introduction
corresponding, deprotonated, saccharinate anion (sac)
acts as a polyfunctional ligand due to the presence of
the negatively charged imino nitrogen, carbonyl oxygen
and sulfonyl oxygen atoms. The most common coordi-
nation mode of sac is ligation through the nitrogen
atom, usually observed in the aquabis(saccharinato)
complexes of divalent transition metals [2–6] and coordi-
nation via the carbonyl or sulfonyl oxygen is less
common.
Saccharin, alternatively named 1,2-benzisothiazoline-
-(2H)one 1,1-dioxide or o-sulphobenzimide in the form
3
of its water soluble sodium salt, is widely used as a non-
caloric sweetener and food additive [1]. The coordina-
tion chemistry of saccharin is interesting. Although no
metal complexes of neutral saccharin are known, the
*
In recent years, we have investigated the synthesis,
spectroscopic, thermal and structural properties of tran-
sition metal complexes of sac with substituted pyridine
Corresponding author. Tel.: +90 362 457 6020; fax: +90 362 457
081.
E-mail address: vtyilmaz@omu.edu.tr (V.T. Yilmaz).
6
0
277-5387/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2005.01.006

694
V.T. Yilmaz et al. / Polyhedron 24 (2005) 693–699
ligands, especially those containing additional donor
groups such as alkylhydroxyl and alkylamine. We have
recently focused our investigations into the complexa-
tion of sac with silver (I), since these species are very rare
and only two silver (I) complex of sac, [Ag(sac)] [7] and
2.3. Physical measurements
IR spectra were recorded a Jasco FT-IR-430 spectro-
photometer as KBr pellets in the frequency range 4000–
À1
300 cm . The elemental analyses (C, H, N and S
[
erature. Recently, we reported the two new silver (I)-sac-
Ag(sac)(PPh ) ] [8] have appeared previously in the lit-
contents) were determined on a Vario EL Elemental
Analyser. Thermal analysis curves (TG and DTA) were
obtained using a Rigaku TG8110 thermal analyzer in a
static air atmosphere. A sample of 5–10 mg was used.
3
2
charinato complexes Na[Ag(sac)] [9] and [Ag (l-sac)2
2
(
l- hep) ] , where hep is N-(2-hydroxyethyl)piperazine
2
n
[
10]. In this study, we report the synthesis, spectroscopic
and thermal characterizations and crystal structures of
two new (saccharinato)silver (I) complexes with 2-pyri-
dineethanol (pyet) and 2-pyridinepropanol (pypr),
namely [Ag (sac) (pyet) ] and [Ag (sac) (pypr) ].
2.4. X-ray structure determination
Intensity data for [Ag (sac) (pyet) ] and [Ag (sac)
4
2
2
2
4
(pypr) ] were collected using Bruker SMART1000
2
2
2
2
4
4
2
CCD and Enraf Nonius KappaCCD area diffractome-
ters with graphite monochromated Mo Ka radiation
˚
(
k = 0.71073 A) at 133(2) and 120(2) K, respectively.
O
OH
The structures were solved with SHELXS 97 and refined
using SHELX 97 [11]. All the non-hydrogen atoms were
refined anisotropically. All the hydrogen atoms, except
the hydroxyl H atoms in [Ag (sac) (pyet) ], were placed
O
C
S
N
N
OH
O
N
sac
pyet
pypr
2
2
2
in idealised locations and refined by riding on their car-
rier atoms, whereas the hydroxyl hydrogen atoms of
Table 1
2
. Experimental
Crystallographic data for [Ag
2
(sac)
2
(pyet)
(pyet)
Ag
2
] and [Ag
4
(sac)
4
(pypr)
(pypr)
Ag
4
2
]
Compounds
[Ag (sac)
2
2
2
]
[Ag
4
(sac)
4
2
]
2
.1. Materials
Empirical formula
Formula weight
T (K)
C
H
28 26
N
4
O
8
S
2
2
C
44
H
38
N
6
O
14
S
4
826.38
133(2)
0.71073
1434.52
120(2)
0.71073
AgNO , Na(sac) Æ 2H O, pyet and pypr were pur-
chased commercially and used as received.
3
2
˚
Radiation, k (A)
Crystal system
Space group
Unit cell dimensions
triclinic
ꢀ
triclinic
ꢀ
2
.2. Preparation of the silver (I) complexes
P1
P1
˚
a (A)
8.1254(6)
8.9300(6)
7.9499(2)
9.7924(3)
Pyet (0.12 g, 1 mmol) was added to an aqueous solu-
tion (20 ml) of AgNO (0.17 g, 1 mmol) and the resulting
˚
b (A)
3
˚
c (A)
10.1782(6)
87.327(3)
74.734(3)
89.735(3)
711.67(8)
1
30.5148(8)
86.1339(8)
88.4027(10)
78.4552(10)
2321.93(11)
2
solution was mixed with an aqueous solution (20 ml) of
Na(sac) Æ 2H O (0.24 g, 1 mmol) at room temperature.
a (°)
b (°)
c (°)
2
The resulting solution was kept in darkness at room
temperature and colorless single crystals of [Ag (sac)
˚
3
V (A )
2
2
Z
(
pyet) ] were obtained after two days. Yield: 82%. d.p.
2
3
(g/cm )
D
c
1.928
2.052
1
3
7
27 °C. Anal. Calc. for C H N O S Ag : C, 40.7; H,
.2; N, 6.8; S, 7.8. Found: C, 40.5; H, 3.3; N, 6.10; S,
.5%.
À1
2
8
26
4
8
2
2
l (mm
F(0 0 0) 412
)
1.582
1416
1.918
h range (°)
Index range (h, k, l )
2.08–30.03
À11/11,
À12/12,
À14/14
14 105
2.92–27.50
À10/10,
À12/12,
À39/39
40 039
The following method was used for the preparation
of [Ag (sac) (pypr) ]. Solid Na(sac) Æ 2H O (0.24 g,
4
4
2
2
1
mmol) was added to a solution (40 ml) of AgNO3
Reflections collected
Independent reflections
Maximum and
(
(
0.17 g, 1 mmol) in a water and isopropanol mixture
1:1, v:v) and this resulted in the formation of a white
4145
0.801 and 0.684
10 637
0.831 and 0.678
minimum transmission
Data/restraints/parameters 4145/0/203
precipitate, which was dissolved by the addition of
pypr (0.14g, 1 mmol) to the reaction medium. After
a week at room temperature, colourless crystals of
10 637/6/649
1.210
0.0894
2
Goodness-of-fit on F
[I > 2r(I)]
R and wR indices
1.073
0.0189
R
1
[
Ag (sac) (pypr) ] were formed. Yield: 25%. d.p.
4 4 2
2
2
0.0203 and 0.0500 0.0999 and 0.2394
0.623 and À0.499 3.138 and À1.512
1
H, 2.7; N, 5.9; S, 8.9. Found: C, 36.5; H, 2.8; N,
32 °C. Anal. Calc. for C H N O S Ag : C, 36.8;
(all data)
Largest difference
peak and hole (e A
4
4
38
6
14
4
4
˚
À3
)
5
.8; S, 9.0%.

V.T. Yilmaz et al. / Polyhedron 24 (2005) 693–699
695
[
Ag (sac) (pyet) ] were refined freely. The molecular
2
to the m(CH) vibrations. The absorption band of the car-
bonyl group of sac in [Ag (sac) (pyet) ] appears at ca.
1649 cm as a very strong, single band. The frequency
of the carbonyl group is characteristic of N-coordinated
sac ligands as reported for Na[Ag(sac)] [9] and Na(sac) Æ
2
2
plots were prepared by using ORTEPIII [12]. The details
of data collection, refinement and crystallographic
parameters are summarized in Table 1.
2
2
2
À1
2
H O [13]. However, the C@O bands in [Ag (sac) -
2
4
4
À1
3
. Results and discussion
(pypr) ] are observed at 1651 and 1626 cm as two
2
distinct and strong bands, indicating the different inter-
actions of the sac ligands. The higher absorption band is
due to an N-bonded sac in which its carbonyl group re-
mains uncoordinated, whereas the band at lower fre-
quency shows the coordination of the sac ligand
3
.1. Synthesis
The mixed-ligand silver (I) complexes of sac with pyet
and pypr were prepared by the direct reaction of silver
I), sac and pyet or pypr in solution. The composition
À1
(
through the carbonyl group, shifting by ca. 25 cm
of the complexes was determined by elemental and TG
analyses. The binuclear complex was obtained in a high
yield over 80%, whereas the yield of the tetranuclear
complex was relatively low (25%). Although no other
complex was isolated from the same reaction solution
of the tetranuclear complex, the low yield of the complex
may be due to the presence of other species with very
high solubility. The elemental analyses were consistent
with their proposed formulae. Both complexes are insol-
compared to the higher band. This shift is in agreement
with the participation of the carbonyl oxygen in metal
bonding as also observed in the IR spectrum of [Ag(sac)]
À1
[14]. The absorption bands at ca. 1580 and 1460 cm
correspond to the ring m(CC) vibrations. The stretching
vibrations of masym.(SO ) and m (SO ) occur character-
istically at ca. 1290 and 1150 cm , respectively. In both
2
sym.
À1
2
complexes, the asymmetric stretching band at around
À1
1280 cm are found to split into two or three bands,
although the S–O distances in both complexes are al-
most identical. Additional peaks at ca. 1330 and 970
uble in warm H O and common alcohols such as meth-
2
anol or ethanol, but soluble in warm H O–alcohol
2
À1
mixtures. Both complexes are non-hygroscopic and
light-stable at room temperature. [Ag (sac) (pyet) ] does
cm are attributed to the symmetric and asymmetric
stretching modes of the CNS moiety of the sac ligands,
respectively. The N-coordination of the py ligands is
confirmed by the absorption bands at around 675
2
2
2
not melt, but decomposes at 127 °C, whereas [Ag
4
(
sac) (pypr) ] melts with decomposition at 132 °C.
4
2
À1
cm due to c(py) [15].
3
.2. IR spectra
3.3. Thermal behaviour
The most significant absorption bands in the IR spec-
tra of the title complexes together with their assignments
are given in Table 2. The position of the bands in the
spectra of both complexes is similar. The strong and
The thermal decomposition pathways of the title
complexes were followed up to 600 °C in a static atmo-
sphere of air. [Ag (sac) (pyet) ] is stable up to 127 °C
and then begins to decompose in three stages. Elimina-
tion of the pyet ligand occurs in the first stage of decom-
position between 127 and 240 °C with three endothermic
effects at 150, 189 and 213 °C. The experimental mass
loss of 29.5% agrees well with the calculated mass loss
of 29.8%. The decomposition of the sac moiety occurs
in the second and third stages in the temperature range
2
2
2
À1
broad bands in the 3330–3350 cm range are attributed
to the m(OH) vibrations of the pyet and pypr ligands.
The relatively weak bands at 2900–3070 cm are due
À1
Table 2
a
Selected IR spectroscopic data
Ag (sac) (pypr)
for [Ag (sac)
2
2
2
(pyet) ]
and
[
4
4
2
]
2
3
50–517 °C with two violently exothermic DTA peaks at
70 and 464 °C (mass loss: found 44.5%, calcd. 44.1%).
Assignment
[Ag
2
(sac)
2
2
(pyet) ]
[Ag
4 4 2
(sac) (pypr) ]
m(OH)
m(CH)
m(CO)
m(CC)
m(CC)
3327s, b
3347s, b
As well as microanalyses, the mass loss calculations sug-
gest that the residue left as a final decomposition prod-
uct is metallic silver. Total mass loss is 74.0% and the
final residue consisting mainly of silver forms 26.0% of
the total mass (calcd. 26.1%).
3066w, 2931vw
1649vs, 1622sh
1587vs
3040w, 2920vw
1651vs, 1626sh
1583vs
1458m
1331s
1458vs
1336s
m
m
m
m
sym(CNS)
asym(SO
sym(SO
2
)
1288vs, 1257s
1151vs
1288vs, 1271vs, 1250vs
1155vs
[
Ag (sac) (pypr) ] follows a different decomposition
4 4 2
2
)
path compared to that of the dimeric complex. It begins
to decompose with melting at 132 °C. The first decom-
position stage between 132 and 231 °C corresponds to
the endothermic removal of two pypr ligands with a
mass loss of 19.4% (calcd. 19.1%). In the next stages,
the exothermic degradation of four sac ligands occurs
asym(CNS)
966vs
773m, 748s
676m
970vs, 953vs
773m, 744s
675s
m(CCC)
c(CH) (py)
b, broad; vw, very weak; w, weak; vs, very strong; s, strong; m, medium
and sh, shoulder.
a
À1
Frequencies in cm
.

696
V.T. Yilmaz et al. / Polyhedron 24 (2005) 693–699
in the 235–528 °C range with a small and two sharp exo-
thermic DTA peaks at 256, 435 and 489 °C, and results
in the formation of silver metal as the end product. The
experimental total mass loss value of 70.5% is consistent
with the calculated value 69.9%.
atom of sac in the adjacent [Ag(sac) (pyet)] unit, exhib-
2
iting a distorted T-shaped AgN O coordination environ-
2
ment. In the dimeric unit, there is an eight-membered
˚
chelate ring with an AgÁ Á ÁAg separation of 5.205 A,
indicating the absence of any interaction between two
silver centres. We have previously observed that the pyet
ligand behaves as a bidentate donor via the N and hy-
droxyl O atoms to other divalent transition metals
3
[
.4. Description of the crystal structure of
Ag (sac) (pyet) ]
2
2
2
[
16–18]. Here, it acts a monodentate ligand through
A molecular view of [Ag (sac) (pyet) ] with the atom
2
the N atom and the hydroxyl O atom remains
uncoordinated.
The Ag–Nsac and Ag–Npyet bond distances are simi-
2
2
numbering scheme is shown in Fig. 1. The selected bond
lengths and angles together with the hydrogen bonding
geometry are given in Table 3. The complex crystallizes
˚
lar, being 2.1753(11) and 2.1444(12) A, respectively.
The Ag–Nsac bond distance is similar to the correspond-
ꢀ
in the triclinic space group P1. The structure consists of
˚
ing values found in [Ag(sac)] [2.16 A] [7], Na[Ag(sac)]
˚
[2.1405(11)] and 2.1570(11) A] [9], but differs from the
individual molecules of dinuclear [Ag (sac) (pyet) ]
units formed from doubly bridged monomeric [Ag-
sac) (pyet)] units joined through the sulfonyl oxygen
2
2
2
˚
bond values reported for [Ag(sac)(PPh ) ] [2.285(8) A]
(
2
3 2
˚
atoms of the sac ligands (Fig. 1). Each silver (I) centre
is three coordinated by an N-bonded sac ligand, an
N-bonded pyet ligand and the bridging sulfonyl oxygen
[8] and [Ag (l-sac) (l-hep) ] [2.084(2) A] [10]. The
2
2
2 n
˚
bridging Ag–Osulfonyl bond distance of 2.6454(10) A is
˚
comparable to that of Na[Ag(sac)] [2.6390(10) A] [9],
but significantly longer than the corresponding bond
˚
in [Ag(sac)] (2.45 A) [7].
The sac ligand is essentially planar with a root-mean-
square (rms) deviation of the non-hydrogen atoms
(excluding the sulfonyl O atoms) from the best least-
squares plane of 0.03 A and the pyet ligand is also pla-
˚
˚
nar with an rms deviation of 0.004 A, but C17 and O17
˚
atoms deviate by 1.375(2) and 2.241(2) A, respectively,
from the best pyet plane. The sac and pyet ligands coor-
dinate to silver (I) in an approximately linear fashion
with an N–Ag–N angle of 159.14(5)°. The dihedral angle
between the planes of sac and pyet is 5.65(6)°, showing
the approximately coplanar arrangement of their ring
systems.
The individual [Ag (sac) (pyet) ] molecules are linked
2
2
2
by strong hydrogen bonds between the hydrogen of the
hydroxyl group and the uncoordinated sulfonyl O atom
of the sac ligands in the neighbouring units, forming a
one-dimensional chain running parallel to the b-axis
(see Fig. 2(a)). The one-dimensional hydrogen bonded
chains are further linked by non-conventional intermo-
2 2 2
Fig. 1. Dimeric molecular unit in [Ag (sac) (pyet) ] with the atom
labelling scheme and 50% thermal ellipsoids (arbitrary spheres for the
H atoms). Symmetry code: (i) = –x, 2 À y, –z.
lecular C–HÁ Á ÁO hydrogen bonds and p(sac)–p(pyet)
˚
stacking interactions [CgÁ Á ÁCg = 3.75(7) A] as shown
in Fig. 2(b).
Table 3
a
2 2 2
Selected geometrical data for [Ag (sac) (pyet) ]
3
[
.5. Description of the crystal structure of
Ag (sac) (pypr) ]
˚
Bond lengths (A) and angles (°)
Ag1–N1
Ag1–N2
2.1753(11)
2.1444(12)
2.6454(10)
N1–Ag1–N2
N1–Ag1–O2
N2–Ag1–O2
159.14(4)
96.11(4)
104.75(4)
4
4
2
i
i
i
Ag1–O2
The molecular structure of the tetranuclear silver (I)
complex [Ag (sac) (pypr) ] with the atom labelling is
4
4
2
D–HÁ Á ÁA
Hydrogen bonds
d(D–H)
d(HÁ Á ÁA)
d(DÁ Á ÁA)
\(DHA)
shown in Fig. 3. The selected bond lengths and angles
are given in Table 4. The compound crystallizes in the
ii
ꢀ
O17–H17Á Á ÁO1
0.82(2)
0.95
0.99
2.02(3)
2.55
2.43
2.8083(17)
3.4133(19)
3.4124(16)
163(2)
150
172
triclinic space group P1 and has two tetrameric mole-
ii
C12–H12Á Á ÁO17
cules in its asymmetric unit with a similar conformation.
The structure consists of isolated molecules of [Ag4
(sac) (pypr) ], which are built up from the bridging of
iii
C16– H16BÁ Á ÁO21
a
Symmetry operations: (i) Àx, 2 À y, Àz; (ii) x, y À 1, z; (ii) 1 À x,
4
2

V.T. Yilmaz et al. / Polyhedron 24 (2005) 693–699
697
i
the two outer silver (I) ions (Ag2 and Ag2 ) are coordi-
nated by a sac ligand and a pypr ligand in a near linear
AgN geometry [N2–Ag2–N3 = 168.6(4)°]. The sac li-
2
gands in the central [Ag (sac) ] unit act as a bidentate
2
2
chelating ligands via the N and carbonyl O atoms form-
ing an roughly planar eight-membered chelate ring. The
central Ag1 pair of silver atoms appear to be interacting
i
based on the Ag–Ag (i = 1 À x, 1 À y, Àz) distance of
˚
.8480(13) A, while Ag2 has no metal neighbours within
˚
A. The separation of the two central Ag3 atoms in the
2
5
second asymmetric molecule of [Ag (sac) (pypr) ] is
2
4
4
˚
.8590(13) A. These silver–silver contacts are some
2
˚
.60 A shorter than twice the van der Waals radius of
0
˚
silver (3.44 A) and clearly indicate a strong bonding
interaction between the Ag1 and the Ag3 centres in
the tetranuclear complex. The Ag–Ag distances found
in [Ag (sac) (pypr) ] are also much shorter than those
4
4
2
reported for other tetranuclear silver units
˚
Ag (SPh) (PPh ) ] [3.1300(3) A] [19] and [Ag (tren
4 4 3 4 4
[
4
+
˚
mim) ) ] [2.929(1) and 3.1313(9) A] [20], where SPh
3 2
(
and tren(mim) are thiolate and tris {2-2(1-methyl)imid-
3
azolyl]methyliminoethyl} amine, respectively. The sig-
nificance of short silver–silver distances has been
˚
debated: Jansen reported a value of 3.30 A as the upper
limit for an AgÁ Á ÁAg contact in coordination com-
pounds [21], whereas Dance et al. [22] stated that since
the linear geometry at silver (I) indicates the fulfilment
of its coordination requirements, there is no bonding
interaction between silver (I) centres as close to each
Fig. 2. (a) A fragment of the hydrogen bonded one-dimensional chain
of [Ag (sac) (pyet) ]. Symmetry code: i = –x, –y, –z. (b) Projection of
the structure of [Ag (sac) (pyet) ] on the ac plane, showing p(sac)–p
pyet) interactions. The phenyl and ethylene H atoms are removed for
clarity.
2
2
2
2
2
2
(
˚
other as 2.886 A in [Ag(SCMeEt) ] . However, we argue
2
n
the central [Ag (sac) ] unit with two [Ag(sac)(pypr)]
2
that there is a significant bonding interaction between
the silver centres at the short distances in the present
[Ag (sac) (pypr) ] complex.
2
units through the sulfonyl oxygen atoms of the sac li-
gands. [Ag (sac) (pypr) ] exhibits two different silver
centres. The two silver (I) ions (Ag1 and its symmetry-
4
4
2
4
4
2
The Ag–Nsac bond distances in [Ag (sac) (pypr) ] are
4 4 2
i
equivalent partner Ag1 ) in the centre exhibit a T-shaped
planar AgNO geometry with three sac ligands, while
similar to those reported for the related silver (I)-sac-
charinato complexes [7,9–11], but the terminal Ag–Nsac
2
Fig. 3. View of tetrameric unit in [Ag
4 4 2
(sac) (pypr) ] with the atom labelling scheme and 50% thermal ellipsoids (arbitrary spheres for the H atoms).
Symmetry code (i) = 1 À x, 1 À y, –z. The asymmetric unit of the complex contains two molecules and one of them was removed for clarity.

698
V.T. Yilmaz et al. / Polyhedron 24 (2005) 693–699
Table 4
a
4 4 2
Selected geometrical data for [Ag (sac) (pypr) ]
˚
Bond lengths (A) and angles (°)
i
i
Ag1–N1
Ag1–O1
Ag1–O5
Ag2–N2
Ag2–N3
2.184(10)
2.230(8)
2.431(9)
N1–Ag1–O1
165.5(3)
106.2(3)
88.2(3)
168.6(4)
99.0(3)
92.2(3)
i
N1–Ag1–O5
O1–Ag1–O5
N2–Ag2–N3
N2–Ag2– O3
N3–Ag2– O3
2.102(10)
2.140(10)
2.960(9)
i
i
i
Ag2–O3
Ag1–Ag1
i
2.8480(13)
D–HÁ Á ÁA
Hydrogen bonds
d(D–H)
d(HÁ Á ÁA)
d(DÁ Á ÁA)
\(DHA)
b
ii
O7–H1Á Á ÁO10
0.90
0.90
0.95
0.95
0.95
1.89
1.89
2.48
2.20
2.38
2.793(14)
2.788(14)
3.360(17)
3.127(17)
3.289(17)
180
180
154
165
161
i
O14–H2Á Á ÁO2
iii
C16–H16Á Á ÁO14
iv
i
C38–H38Á Á ÁO7
C40–H40Á Á ÁO2
a
Symmetry operations: (i) 1 À x, 1 À y, Àz; (ii) 1 À x, 1 À y, 1 À z;
(
iii) 1 + x, y, z; and (iv) 1 + x, y À 1, z.
b
O10, O17 and C38 and C40 atoms belongs to the second molecule
in the asymmetric unit of the compound.
bond distances are noticeably longer than the corre-
sponding bonds and the Ag–Osac bonds in the central
˚
unit. The Ag–Ocarbonyl bond distance of 2.230(8) A is al-
˚
most identical to that observed in [Ag(sac)] [2.22 A] [7],
but slightly shorter than those found in [Ag (l-sac) (l-
2
2
˚
hep) ] [2.2535(11) and 2.3010(14) A] [10]. The bridging
2
n
˚
Ag–Osulfonyl bond distance of 2.431(9) A is similar to the
˚
equivalent value observed in [Ag(sac)] (2.45 A) [7], but is
4 4 2
Fig. 4. A view of the unit cell of [Ag (sac) (pypr) ] viewed along the a
˚
significantly shorter than the 2.6390(10) A found in
axis. It shows the packing of the tetramers to form a herringbone
motif. The phenyl and ethylene H atoms are removed for clarity.
Na[Ag(sac)] [9]. Furthermore, there is a weaker interac-
tion between the sulfonyl O atoms of the sac ligands
in the central unit and the silver (I) centres at the
a herring-bone motif. The two molecules in the asym-
metric unit of the structure are connected by strong
terminal units, yielding a Ag–Osulfonyl bond distance of
˚
˚
2.960(9) A and probably suggesting the ‘‘semi-coordina-
tion’’ ofthesulfonylgroupofsactosilver(I). TheAg–Npypr
intermolecular O–HÁ Á ÁO bonds (HÁ Á ÁO = 1.89 A),
involving the hydroxyl H of pypr and sulfonyl O of
sac. The O10, O17 and C38 and C40 atoms belongs to
the second molecule in the asymmetric unit of the com-
pound. The strong hydrogen bonds form hydrogen
bonded dimers, which are further linked by C–HÁ Á ÁO
interactions, resulting in a layered structure. The C38–
˚
bond distance is 2.140(10) A. Similarly, the hydroxyl
group of pypr is uncoordinated in [Ag (sac) (pypr) ] in
4
4
2
contrast to the bidentate coordination behaviour in the
presence of divalent transition metals [23–25]. This
may be explained in terms of hard and soft acids and
bases. As a soft acid, silver (I) will not prefer a hard base
OH for coordination.
iv
H38Á Á ÁO7 bond has an exceptionally short HÁ Á ÁO con-
˚
tact of 2.20 A, but this may arise from unmodelled
The ring systems of sac and pypr are planar. The rms
deviations from the best planes of the sac1 with N1, sac2
˚
with N2 and pypr species are 0.010, 0.016 and 0.012 A,
disorder of some of the carbon atoms in the py ring con-
taining C38.
respectively. The displacement of the silver (I) ions from
the corresponding planes is as follows: Ag1 from
4. Supplementary material
˚
sac1 = 0.356(11) A, Ag2 from sac2 = 0.212(9) A and
˚
˚
Ag2 from pypr = 0.0429(19) A. The planes of sac and
pypr coordinated the terminal Ag2 atoms are roughly
coplanar with a dihedral angle of 10.7(6)°.
Crystallographic data for the structures reported in
the paper have been deposited at the CCDC as supple-
mentary data, CCDC Nos. 253479 and 253480 for
[Ag (sac) (pyet) ] and [Ag (sac) (pypr) ], respectively.
Copies of the data can be obtained on application to
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK
The unit-cell packing of the molecules of [Ag (sac)
(pypr) ] is shown in Fig. 4. Relevant hydrogen bonds
are listed in Table 4. The packing of the tetramers forms
4
4
2
2
2
4
4
2
2

V.T. Yilmaz et al. / Polyhedron 24 (2005) 693–699
699
(Fax: +44 1223 336033; E-mail: deposit@ccdc.cam.ac.
uk; http://www.ccdc.cam.ac.uk).
[10] S. Hamamci, V.T. Yilmaz, W.T.A. Harrison, J. Mol. Struct. 734
2005) 191.
(
[11] G.M. Sheldrick, SHELX-97, Programs for Crystal Structure Anal-
ysis, University of G o¨ ttingen, Germany, 1997.
[12] L.J. Farrugia, J. Appl. Crystallogr. 30 (1997) 565.
Acknowledgement
[13] O.V. Quinzani, S. Tarulli, O.E. Piro, E.J. Baran, E.E. Castellano,
Z. Naturforsch. B52 (1997) 183.
[
[
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15] K. Nakamoto, Infrared and Raman Spectra of Inorganic and
Coordination Compounds, Part B, 5th ed., Wiley, New York,
This work was supported financially by Ondokuz
Mayis University.
1
16] V.T. Yilmaz, S. Hamamci, C. Thone, Cryst. Res. Technol. 37
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