Coordination networks constructed with supramolecular synthon RX-C{triple bond, long}C?Agn (n = 4, 5; RX = halophenyl)

Article abstract of DOI:10.1016/j.poly.2009.05.004

Eight new silver(I) double salts: AgL¹·2AgCF₃COO (1), AgL¹·3AgNO₃ (2), 2AgL²·5AgCF₃COO·2CH₃CN·H₂O (3), 4AgL³·6AgCF₃COO·5CH₃CN (4), 4Ag

Full text of DOI:10.1016/j.poly.2009.05.004

Polyhedron 28 (2009) 2684–2692
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Coordination networks constructed with supramolecular synthon
RX–C„CꢀAgn (n = 4, 5; RX = halophenyl)
*
Siegfried M.J. Wang, Thomas C.W. Mak
Department of Chemistry and Centre of Novel Functional Molecules, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
a r t i c l e i n f o
a b s t r a c t
Eight new silver(I) double salts: AgL1ꢁ2AgCF3COO (1), AgL1ꢁ3AgNO3 (2), 2AgL2ꢁ5AgCF3COOꢁ2CH3CNꢁH2O
(3), 4AgL3ꢁ6AgCF3COOꢁ5CH3CN (4), 4AgL4ꢁ6AgCF3COOꢁ5CH3CN (5), 2AgL5ꢁ4AgCF3COOꢁNC(CH2)4CN (6),
2AgL5ꢁ4AgCF3COOꢁ2CH3CN (7) and AgL6ꢁ2CF2(CF2COOAg)2ꢁ2CH3CN (8) (L1 = 4-iodophenylethynide;
Article history:
Received 11 March 2009
Accepted 5 May 2009
Available online 13 May 2009
L
2 = 3,4-dichlorophenylethynide; L3 = 3-chlorophenylethynide; L4 = 3-bromophenylethynide; L5 = 2-
chlorophenylethynide; L6 = 2-fluorophenylethynide) have been synthesised and characterized by X-ray
crystallography. All compounds contain the silver–halophenylethynide supramolecular synthon
RXꢂC„CꢀAgn (n = 4, 5). In particular, the three-dimensional supramolecular structures in 1 and 2 are sta-
bilized by strong Agꢁ ꢁ ꢁI interactions, while that in 3 is consolidated by both Agꢁ ꢁ ꢁCl and van der Waals
type Fꢁ ꢁ ꢁCl interactions. In isomorphous compounds 4 and 5, the presence of respective Fꢁ ꢁ ꢁCl or Fꢁ ꢁ ꢁBr
contact contributes to the stability of the network. The silver aggregates in 6, 7 and 8 are stabilized by
Agꢁ ꢁ ꢁCl or Agꢁ ꢁ ꢁF interactions between the ortho-halo substituent and the Agn basket.
Ó 2009 Elsevier Ltd. All rights reserved.
Keywords:
Coordination network
Halogenꢁ ꢁ ꢁhalogen
Silver–ethynide
Silverꢁ ꢁ ꢁhalogen
Supramolecular synthon
1. Introduction
2AgCF3COO (1), AgL1ꢁ3AgNO3 (2), 2AgL2ꢁ5AgCF3COOꢁ2CH3CNꢁ H2O
(3), 4AgL3ꢁ6AgCF3COOꢁ5CH3CN (4), 4AgL4ꢁ6AgCF3COOꢁ5CH3CN
The silver(I) cation, like other easily-polarizable metal cations,
tends to associate with ‘soft’ non-metals such as sulfur, selenium,
tellurium and iodine. Accordingly, intermolecular interactions of
the type Agꢁ ꢁ ꢁX (X = F, Cl, Br, I) have been used in the design and
assembly of supramolecular structures [1]. Besides using halogen
ions in their bare forms [2], several reports have demonstrated
the feasibility of using X-aryl moieties to incorporate silverꢁ ꢁ ꢁhalo-
gen interactions into coordination networks. The Agꢁ ꢁ ꢁI-aryl inter-
action (with Agꢁ ꢁ ꢁI distances in the range of 2.719–3.357 Å)
commonly occurs [1], while Agꢁ ꢁ ꢁBr-aryl and Agꢁ ꢁ ꢁCl-aryl are less
studied [3], and Agꢁ ꢁ ꢁF-aryl is rarely reported.
(5), 2AgL5ꢁ4AgCF3COOꢁNC(CH2)4CN (6), 2AgL5ꢁ4AgCF3COOꢁ2CH3CN
(7) and AgL6ꢁ2CF2(CF2COOAg)2ꢁ2CH3CN (8) (L1 = 4-iodophenylethy-
nide; L2 = 3,4-dichlorophenylethynide; L3 = 3-chlorophenylethy-
nide; L4 = 3-bromophenylethynide; L5 = 2-chlorophenylethynide;
L6 = 2-fluorophenylethynide), which are stabilized by both sil-
ver(I)–ethynide and silver(I)ꢁ ꢁ ꢁhalogen interactions. In addition,
CAHꢁ ꢁ ꢁX (X = Br, Cl) hydrogen bonds exist in 4 and 5, respectively,
and multiple halogenꢁ ꢁ ꢁhalogen van der Waals interactions con-
tribute to network stabilization in 3, 4, 5 and 6.
2. Experimental
In recent years, we have carried out a systematic investigation
on the construction of silver–organic coordination networks based
on silver–ethynide supramolecular synthons, which comprise sil-
ver aggregates stabilized by argentophilicity and silver–ethynide
2.1. General
All chemicals are used as received from AldrichÒ with no further
purification. Degassing and desiccation are not performed for sol-
vents of analytical reagent grade.
interactions of the r, p and mixed (r, p) types [4]. Among the com-
pounds studied thus far, two examples exhibit signꢂificant sil-
verꢁ ꢁ ꢁhalogen interaction involving the Fꢂ and PF2O2 ions [5].
Therefore, it is of interest to us to investigate the role played by
the silverꢁ ꢁ ꢁhalogen interactions in coordination network assembly
based on the silver–ethynide supramolecular synthon [4b,6]. In
this paper, we report the synthesis and structure characteri-
zation of eight new silver(I) halophenylethynide complexes: AgL1ꢁ
2.1.1. Synthesis of polymeric silver(I) halophenylethynides
[AgL1]n. (4-Iodophenylethynyl)trimethylsilane (1.00 g, 3.33
mmol) was dissolved in a mixed solvent of 20 mL acetonitrile,
2 mL triethylamine and 40 mL methanol, to which was subse-
quently added 10 mL acetonitrile solution containing dissolved sil-
ver nitrate (0.623 g, 3.66 mmol). A white precipitate formed
immediately. After stirring for 10 h, the crude polymeric product
was filtered off and washed with 20 mL acetonitrile, 10 mL diethyl
* Corresponding author. Tel.: +852 2609 6279; fax: +852 2603 5057.
E-mail address: tcwmak@cuhk.edu.hk (T.C.W. Mak).
0277-5387/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2009.05.004

S.M.J. Wang, T.C.W. Mak / Polyhedron 28 (2009) 2684–2692
2685
ether and 10 mL distilled water trice, and then stored under ꢂ10 °C
in wet form. Yield: 72% (based on TMS-C„CPhI-4). IR:
C: 23.85% (24.18%), H: 1.28% (1.16%). IR: v = 2048, 2012 cmꢂ1
(w, C„C).
m
m
= 2034 cmꢂ1 (w,
mC„C).
[AgL2]n. 3,4-Dichlorophenylacetylene (1.00 g, 5.85 mmol) was
2.1.2.6. 2AgL5ꢁ4AgCF3COOꢁNC(CH2)4CN (6). AgBF4 (0.384 g, 2 mmol)
and AgCF3COO (0.220 g, 1 mmol) were dissolved in the mixture
of 1 mL distilled water, 0.5 mL acetonitrile and 0.1 mL adiponitrile,
to which [AgL5]n (ꢃ0.050 g) was added subsequently. The mixture
was stirred for 4 h. The undissolved solid was then filtered off. Col-
orless block-like crystals were formed one week later. Elemental
analysis (calculated): C: 24.21% (24.37%), H: 1.20% (1.09%). IR:
dissolved in a mixture of 2 mL triethylamine and 60 mL acetoni-
trile, to which a 10 mL acetonitrile solution of silver nitrate
(1.00 g, 5.88 mmol) was subsequently added. After stirring for
10 h, the crude polymeric salt was filtered off and washed with
20 mL acetonitrile and 10 mL distilled water trice, and then stored
under ꢂ10 °C in wet form. Yield: 80%, IR:
m mC„C).
= 2026 cmꢂ1 (w,
Similar procedures were conducted in obtaining the following four
m mC„C).
= 2041 cmꢂ1 (w,
crude polymeric silver salts.
[AgL3]n. This material was prepared employing 3-chlorophenyl-
2.1.2.7. 2AgL5ꢁ4AgCF3COOꢁ2CH3CN (7). AgBF4 (0.384 g, 2 mmol) and
AgCF3COO (0.220 g, 1 mmol) were dissolved in 1 mL distilled
water, and subsequently [AgL5]n (ꢃ0.050 g) was added. The mix-
ture was stirred vigorously for 1 h. During that time, 0.4 mL aceto-
nitrile was introduced. The undissolved solid was then filtered off,
and the filtrate stored under 25 °C in the dark. Plate-like crystals
were obtained in one week. Elemental analysis (calculated):
acetylene. Yield: 80%, IR:
[AgL4]n. This material was prepared employing 3-bromophenyl-
acetylene. Yield: 80%, IR: C„C).
= 2010 cmꢂ1 (w,
[AgL5]n. This material was prepared employing 2-chlorophenyl-
acetylene. Yield: 60%, IR: C„C).
= 2025 cmꢂ1 (w,
[AgL6]n. This material was prepared employing 2-fluorophenyl-
acetylene. Yield: 56%, IR: C„C).
= 2054 cmꢂ1 (w,
m mC„C).
= 2010 cmꢂ1 (w,
m
m
m
m
m
m
C: 23.19% (23.15%), H: 1.10% (0.97%). IR: v = 2058 cmꢂ1
(mC„C).
2.1.2. Synthesis of silver(I) halophenylethynide complexes
2.1.2.8. AgL6ꢁ2Ag2C3F6(COO)2ꢁ2CH3CN (8). AgBF4 (0.384 g, 2 mmol),
hexafluoroglutaric acid (0.120 g, 0.5 mmol) and Ag2O (0.116 g,
0.5 mmol) were dissolved in a mixture of 1 mL distilled water
and 0.2 mL acetonitrile, to which [AgL6]n (ꢃ0.050 g) was added
subsequently. The mixture was stirred for 4 h and filtered after-
wards. Colorless needle-like crystals were formed after two weeks.
Elemental analysis (calculated): C: 21.81% (21.72%), H: 1.00%
2.1.2.1. AgL1ꢁ2AgCF3COO (1). AgBF4 (0.384 g, 2 mmol) and AgCF3-
COO (0.220 g, 1 mmol) were dissolved in 1 mL distilled water,
and subsequently [AgL1]n (ꢃ0.050 g) was added. The mixture was
stirred vigorously for 1 h. During that time, 0.1 mL acetonitrile
was introduced. The undissolved solid was then filtered off, and
the filtrate stored under 25 °C in the dark. Crystallization happened
two weeks later. Elemental Analysis (calculated): C: 18.78%
(0.83%). IR:
m mC„C).
= 2057 cmꢂ1 (w,
(18.56%), H: 0.51% (0.52%). IR:
m mC„C).
= 2032 cmꢂ1 (w,
2.2. X-ray crystallography
2.1.2.2. AgL1ꢁ3AgNO3. (2). AgNO3 (0.600 g, 3.5 mmol) was dissolved
in a mixture of 1 mL distilled water and 0.2 mL acetonitrile, and
subsequently [AgL1]n (ꢃ0.050 g) was added. The mixture was stir-
red for 1 h. The undissolved solid was then filtered off, and the fil-
trate was stored under 25 °C in the dark. Crystallization happened
two weeks later. Elemental Analysis (calculated): C: 11.16%
Selected crystals were used for data collection on a BrukerAXS
Kappa APEX2 CCD diffractometer at 293 K using frames of oscilla-
tion range 0.5° (Phi scan and Omega scan) with 2° < h < 28° (com-
pound 1, 2, 3, 6, 7, 8) or on a BrukerAXS SMART 1000 CCD
diffractometer at 293 K using frames of oscillation range 0.3°
(Omega scan) with 2° < h < 28° (compound 4, 5). Empirical absorp-
tion corrections based on multi-scan method were applied using
the SADABS program [7]. The structures were solved by the direct
method and refined by full-matrix least squares based on F2 using
the programs in SHELXTL package [8]. The crystal data and details of
refinement are summarized in Table 1.
(11.38%), H: 0.50% (0.48%). IR:
m mC„C).
= 2022 cmꢂ1 (w,
2.1.2.3. 2AgL2ꢁ5AgCF3COOꢁ2CH3CNꢁH2O (3). AgBF4 (0.384 g, 2 mmol)
and AgCF3COO (0.220 g, 1 mmol) were dissolved in 1 mL distilled
water, and subsequently [AgL2]n (ꢃ0.050 g) was added. The mix-
ture was stirred vigorously for 1 h. During that time, 0.1 mL aceto-
nitrile was introduced. The undissolved solid was then filtered off,
and the filtrate stored under 25 °C in the dark. Small plate-like
crystals were obtained two months later. Elemental analysis (cal-
culated): C: 20.30% (20.45%), H: 1.06% (0.92%), IR: v = 2048 cmꢂ1
3. Results and discussion
3.1. AgL1ꢁ2AgCF3COO (1)
(w, mC„C).
2.1.2.4. 4AgL3ꢁ6AgCF3COOꢁ5CH3CN (4). AgBF4 (0.384 g, 2 mmol) and
AgCF3COO (0.220 g, 1 mmol) were dissolved in 1 mL distilled
water, and subsequently [AgL3]n (ꢃ0.050 g) was added. The mix-
ture was stirred vigorously for 1 h. During that time, 0.4 mL aceto-
nitrile was introduced. The undissolved solid was then filtered off,
and the filtrate stored under 25 °C in the dark. Plate-like crystals
were obtained in one week. Elemental analysis (calculated): C:
25.75% (25.90%), H: 1.40% (1.25%). IR: v = 2065, 2000 cmꢂ1
As shown in Fig. 1, compound 1 features a centrosymmetric Ag6
aggregate derived from two inversion-related Ag4 baskets sharing
one silver edge (Ag3ꢁ ꢁ ꢁAg3a). An ethynide group (C1„C2) is at-
tached to each Ag4 basket in the l4– , , ,
g2 g2 g1 g1 ligation mode.
The distances between silver atoms range from 2.815(1) to
3.238(1) Å, suggesting the existence of significant argentophilic
interaction. Such silver baskets and ethynide ligation mode are
consistent with those in the previously established R–C„CꢀAgn
(n = 4, 5) supramolecular synthon [4b,6].
(w, mC„C).
The connection of Ag6 aggregates by bridging trifluoroacetate li-
gands across crystallographic inversion centers gives rise to a two-
dimensional coordination network, as shown in Figs. 1 and 2. The
carboxyl group containing oxygen atoms (O3, O4) adopts the
2.1.2.5. 4AgL4ꢁ6AgCF3COOꢁ5CH3CN (5). AgBF4 (0.384 g, 2 mmol) and
AgCF3COO (0.220 g, 1 mmol) were dissolved in 1 mL distilled
water, and subsequently [AgL4]n (ꢃ0.050 g) was added. The mix-
ture was stirred vigorously for 1 h. During that time, 0.4 mL aceto-
nitrile was introduced. The undissolved solid was then filtered off,
and the filtrate stored under 25 °C in the dark. Needle-like crystals
were obtained in one week. Elemental analysis (calculated):
l
4–O,O,O0,O0 ligation mode generates a centrosymmetric (AgCF3-
COO)2 unit (Fig. 2). The distance between two silver atoms
(Ag1ꢁ ꢁ ꢁAg1a) within this unit is 2.993(1) Å, which lies within the
argentophilic distance range; under such linkage, the silver

2686
S.M.J. Wang, T.C.W. Mak / Polyhedron 28 (2009) 2684–2692
Table 1
Crystallographic data of compound 1–8.
Compound
Formula
1
2
3
4
5
6
7
8
C12H4O4
F6IAg3
776.66
Triclinic
P 1
8.3284(5)
10.0353(6)
11.0673(7)
84.762(1)
74.189(1)
71.732(1)
845.11(9)
2
C8H4N3O9
Ag4I
844.52
Monoclinic
Cc
8.9094(4)
25.562(1)
7.1395(3)
90.00
112.045(1)
90.00
C30H14N2O11
Ag7Cl4F15
1760.32
Monoclinic
Cc
23.416(1)
7.2186(4)
27.567(2)
90.00
102.212(2)
90.00
4554.3(4)
4
C54H31N5O12
F18Ag10Cl4
2504.34
Triclinic
P 1
14.695(5)
15.336(6)
17.685(7)
73.350(5)
70.084(5)
83.571(5)
3590(2)
2
C54H31N5O12
F18Ag10Br4
2682.18
Triclinic
P 1
14.846(5)
15.362(5)
17.715(5)
73.298(5)
70.934(5)
84.054(5)
3657(2)
2
C30H16N2O8
Ag6Cl2F12
1478.57
Triclinic
P 1
11.9499(4)
13.8333(4)
13.9590(4)
114.503(1)
94.962(1)
107.901(1)
1936.1(1)
2
C28H14N2O8
Ag6Cl2F12
1452.53
Triclinic
P 1
12.008(6)
13.150(7)
13.706(7)
67.21(1)
81.68(1)
80.18(1)
1959(2)
2
C22H10N2O8
Ag5F13
1216.67
Triclinic
P 1
9.2084(2)
13.3717(6)
13.9829(4)
113.748(1)
104.932(1)
95.177(1)
1485.7(1)
2
Fw
Crystal system
Space group
a (Å)
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
V (Å3)
1507.1(1)
4
Z
Dc (mg/m3)
Total reflection
Reflection [I > 2
Parameters
Rint
3.052
28,642
2882
3.722
26,840
2675
2.567
49,585
7438
2.317
24,230
9689
2.436
20,845
7085
2.536
70,980
6457
575
0.0231
0.0220
0.0481
1.089
2.463
79,851
5645
2.720
23,152
5423
r(I)]
252
215
712
931
873
557
441
0.0271
0.0271
0.0619
1.053
1.285
1.335
0.0261
0.0181
0.0431
1.110
0.926
1.216
0.0397
0.0336
0.0770
1.039
1.164
1.295
0.0365
0.0485
0.1334
1.022
1.635
1.387
0.0536
0.0689
0.1870
1.007
1.511
1.092
0.0426
0.0380
0.0951
1.016
1.141
1.115
0.0193
0.0216
0.0538
1.086
1.212
1.202
R1 (obsd)
wR2 (all)
S (GooF)
qmax (eÅꢂ3
ꢂ
)
0.990
0.885
qmin (eÅꢂ3
)
aggregates are extended into an infinite silver chain along the a
direction. Furthermore, the Ag6 aggregates in parallel silver chains
are also cross-linked by the other independent trifluoroacetate li-
gand (containing O1, O2) acting in the
l
3–O,O,O0 mode to form a
web-like layer in the ab plane, as shown in Figs. 1 and 2. It is nota-
ble that bridging between silver chains is assisted by silverꢁ ꢁ ꢁfluoro
close contact. The bridged Ag2ꢁ ꢁ ꢁF9 distance is 3.088(1) Å, being
slightly shorter than the sum of van der Waals radii of F and Ag
on the Bondi scale [9]. This kinds of close contact between silver
and fluorine rarely occurs, though an example of this interaction
was reported in our previous work on the crystal structure of
Ag2C4ꢁ2AgFꢁ10AgC2F5CO2ꢁCH3CNꢁ12H2O [5].
As shown in Fig. 3, the iodophenyl ethynide ligands are arrayed
between the above-mentioned web-like layers, alternatively run-
ning parallel or anti-parallel with respect to the c axis. Their ethy-
nide terminals are inserted into corresponding silver baskets, while
Fig. 2. Two-dimensional coordination network lying in the ab plane of complex 1.
CF3 moieties of trifluoroacetate ions are omitted for clarity. Symmetry code: a 2 ꢂ x,
ꢂy, 1 ꢂ z; b 1 ꢂ x, 1 ꢂ y, 1 ꢂ z; c 1 + x, y, z.
Fig. 1. Two Ag6 aggregates in complex 1, which are linked by carboxyl groups and
Agꢁ ꢁ ꢁF close contacts. For clarity, some CF3 moieties of trifluoroacetate anions and
all hydrogen atoms are omitted. Selected bond lengths [Å]: C1„C2 1.222(6),
C1ꢁ ꢁ ꢁAg1 2.341(5), C1ꢁ ꢁ ꢁAg2 2.164(5), C1ꢁ ꢁ ꢁAg3 2.253(4), C1ꢁ ꢁ ꢁAg3a 2.523(5),
C2ꢁ ꢁ ꢁAg1 2.842(5), C2ꢁ ꢁ ꢁAg3a 2.673(5), Ag1ꢁ ꢁ ꢁAg2 3.026(1), Ag1ꢁ ꢁ ꢁAg3 3.238(1),
Ag2ꢁ ꢁ ꢁAg3 2.781(1), Ag3ꢁ ꢁ ꢁAg3a 2.815(1). Symmetry code: a 1 ꢂ x, ꢂy, 1ꢂz; b 1 ꢂ x,
1 ꢂ y, 1 ꢂ z.
Fig. 3. Packing diagram of complex 1 in the ac plane. Trifluoroacetate anions are
omitted for clarity, except for one bridging carboxyl moiety. Symmetry code: a
2 ꢂ x, ꢂy, 1 ꢂ z; b x, y, 1 + z; c 2 ꢂ x, ꢂy, ꢂz; d 1 ꢂ x, ꢂy, ꢂz; e 2 ꢂ x, ꢂy, ꢂz.

S.M.J. Wang, T.C.W. Mak / Polyhedron 28 (2009) 2684–2692
2687
each iodophenyl group is coordinated to a pair of silver atoms of
the (AgCF3COO)2 structural unit by adopting the 2–I mode. The
l
distance between silver and iodine atoms are 2.906(1) Å
(Ag1ꢁ ꢁ ꢁI1c) and 3.394(1) Å (Ag1ꢁ ꢁ ꢁI1b), indicating the presence of
strong silverꢁ ꢁ ꢁiodine interactions. The interlaced phenyl rings
are stacked via two types of edge-to-edge
p p interaction of
ꢁ ꢁ ꢁ
intermediate strength [6b]: C4–C5ꢁ ꢁ ꢁC5e–C4e 3.670(1) Å and
C7–C8ꢁ ꢁ ꢁC8d–C7d 3.563(1) Å. The corresponding center-to-center
distances of adjacent phenyl rings are 4.149(1) Å (I) and
4.199(1) Å (II). Thus the iodophenyl ethynide ligands connect the
web-like layers altogether to generate a 3D network.
3.2. AgL1ꢁ3AgNO3 (2)
In the non-centrosymmetric structural unit (Fig. 4) of com-
Fig. 5. Unit-cell content of complex 2. Hydrogen atoms are omitted for clarity. Only
those nitrate anions that bridge the silver baskets are included.
pound 2, the ethynide group (C1„C2) inserts into a stand-alone
Ag4 basket in the l4– , , ,
g2 g2 g1 g1 ligation mode, being similar to
that in complex 1. The distances between the silver atoms range
from 2.909(1) to 3.021(1) Å. Three of the four silver atoms are coor-
dinated by nitrate ions. There is one intramolecular CAHꢁ ꢁ ꢁO
hydrogen bond between C8 and O9, in which the Cꢁ ꢁ ꢁO distance
is 3.177(6) Å and \OHC is 165o.
network built by nitrate linkages and silverꢁ ꢁ ꢁiodo interactions is
stabilized by inter-layer
p p interaction.
ꢁ ꢁ ꢁ
3.3. 2AgL2ꢁ5AgCF3COOꢁ2CH3CNꢁH2O (3)
As shown in Fig. 4, adjacent structural units in compound 2 are
linked by nitrate ions (upper limit of AgAO bonding distance taken
In the structural unit of compound 3, two parallelly aligned
as 2.61 Å) [10] and silverꢁ ꢁ ꢁiodo interactions in the
l2–I mode:
3,4-dichlorophenylethynide ligands are inserted into separate Ag5
each unit is connected to twelve neighboring ones (see Supple-
mentary Material) to yield a three-dimensional network directly.
The Agꢁ ꢁ ꢁI distances are 3.211(1) Å for Ag1ꢁ ꢁ ꢁI1 and 2.814(1) Å
for Ag4ꢁ ꢁ ꢁI1, respectively. With reference to the van der Waals radii
of silver (1.72 Å) and iodine (1.95 Å) on the Bondi scale [9], the two
contacts are ranked as strong silverꢁ ꢁ ꢁiodo interactions.
baskets by adopting the l5– , , , , – , , ,
g2 g2 g2 g1 g1 and l4 g2 g2 g2 g1
ligation modes. The silver baskets share one edge to give an Ag8
aggregate, and such aggregates are anchored and stabilized by tri-
fluoroacetate anions (Fig. 6). The Ag8 aggregates are further con-
nected together by sharing type Ag5ꢁ ꢁ ꢁAg6 edges of length
3.201(1) Å to form a silver chain. Two types of face-to-face
p p
ꢁ ꢁ ꢁ
Along the b direction, the contents in the ac plane are arranged
in the infinite sequence: silver baskets, nitrate ions, silver baskets,
organic ligands, . . .. As shown in Fig. 5, the phenyl rings are inter-
laced by 60° and stacked alternately, forming face-to-face
interaction (centroid-to-centroid distance 3.595(1) Å) along the c
direction. Alternatively, adjacent layers containing the stacks
interactions occur between neighboring phenyl rings to form a zig-
zag stack alongside the extended silver chain. The distances be-
tween the ring centroids are 3.999(1) and 3.899(1) Å (average
inter-planar distance: 3.63 and 3.71 Å), respectively.
p
ꢁ ꢁ ꢁ
p
p
are linked via silverꢁ ꢁ ꢁiodo interaction and bridged by nitrate an-
ions attached to silver baskets: each iodine atom interacts with
two vertices belonging to silver baskets in adjacent layers, and
the linkages of nitrate anions occur mainly between silver baskets
that are aligned head-to-head. In this manner, a three-dimensional
Fig. 6. Metal-ligand bonding in 3. All hydrogen atoms, acetonitrile molecules, a
water molecule, and CF3 moieties of trifluoroacetate anions are omitted for clarity.
Selected bond lengths [Å]: C1„C2 1.191(11), C9„C10 1.216(10). C1ꢁ ꢁ ꢁAg1
2.089(7), C1ꢁ ꢁ ꢁAg4 2.524(8), C1ꢁ ꢁ ꢁAg5 2.567(7), C1ꢁ ꢁ ꢁAg6 2.662(8), C1ꢁ ꢁ ꢁAg7
2.413(7), C2ꢁ ꢁ ꢁAg4 2.984(8), C2ꢁ ꢁ ꢁAg5 2.989(7), C2ꢁ ꢁ ꢁAg7 2.677(7), C9ꢁ ꢁ ꢁAg2
2.070(7), C9ꢁ ꢁ ꢁAg4 2.387(7), C9ꢁ ꢁ ꢁAg5a 2.476(7), C9ꢁ ꢁ ꢁAg6a 2.362(7), C10ꢁ ꢁ ꢁAg4
2.780(7), C10ꢁ ꢁ ꢁAg5a 2.959(7), C10ꢁ ꢁ ꢁAg6a 2.732(7), Ag1ꢁ ꢁ ꢁAg4 3.136(1), Ag1ꢁ ꢁ ꢁAg5
3.020(1), Ag1ꢁ ꢁ ꢁAg6 3.179(1), Ag1ꢁ ꢁ ꢁAg7 3.009(1), Ag2ꢁ ꢁ ꢁAg3 3.080(1), Ag2ꢁ ꢁ ꢁAg5a
2.951(1), Ag2ꢁ ꢁ ꢁAg6a 3.065(1), Ag4ꢁ ꢁ ꢁAg2 2.954(1), Ag4ꢁ ꢁ ꢁAg6 2.920(1), Ag5ꢁ ꢁ ꢁAg6
3.201(1), Ag7ꢁ ꢁ ꢁAg5a 3.097(1). Symmetry code: a x, y ꢂ 1, z; b x, y + 1, z.
Fig. 4. Coordination geometry in 2 (50% thermo ellipsoids for Ag atoms), and the
bridging of adjacent units. Selected bond lengths [Å]: C1„C2 1.225(7), C1ꢁꢁꢁAg1
2.308(6), C1ꢁ ꢁ ꢁAg2 2.234(5), C1ꢁ ꢁ ꢁAg3 2.191(6), C1ꢁ ꢁ ꢁAg4 2.304(6), C2ꢁ ꢁ ꢁAg1
2.873(6), C2ꢁ ꢁ ꢁAg4 2.683(6), Ag1ꢁ ꢁ ꢁAg2 3.054(1), Ag1ꢁ ꢁ ꢁAg3 3.012(1), Ag2ꢁ ꢁ ꢁAg3
2.947(1), Ag2ꢁ ꢁ ꢁAg4 3.011(1), Ag3ꢁ ꢁ ꢁAg4 2.909(1), O9ꢁ ꢁ ꢁC8 3.177(5). Symmetry
code: a 1 + x, y, 1 + z; b 1 + x, 1 ꢂ y, 0.5 + z; c x, 1 ꢂ y, 0.5 + z .

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S.M.J. Wang, T.C.W. Mak / Polyhedron 28 (2009) 2684–2692
l
3–O,O0 (O5–O6) trifluoroacetate groups with further stabilization
by argentophilic interaction (Ag3ꢁ ꢁ ꢁAg2 3.080(1) Å). Weak inter-
chain silverꢁ ꢁ ꢁchloro interaction between Ag3 and Cl1 (Ag3ꢁ ꢁ ꢁCl1
3.287(2) Å) occurs in the c direction to generate a supramolecular
layer, and inter-layer Fꢁ ꢁ ꢁCl contact in the a direction is of the
van der Waals type [9,11] (F19ꢁ ꢁ ꢁCl3 3.23(1) Å). (Fig. 7).
3.4. 4AgL3ꢁ6AgC2F5COOꢁ5CH3CN (4) and 4AgL4ꢁ6AgC2F5COOꢁ5CH3CN
(5)
Compound 4 and 5 are nearly isomorphous with the same kind
of centrosymmetric structural unit. In compound 4 (Fig. 8), four
parallel-related ethynides are inserted into respective Ag5 baskets
by adopting l5
g1 (C25„C26) l5
tion modes. The only difference in compound 5 is that C17„C18
adopts the l5
1 mode. By sharing edges, the Ag5 bas-
kets are further united to form a columnar fragment. Four phenyl
rings in each fragment are aligned on the same side of the silver
–
g2
,
g2
,
g2
,
g1
,
g1 (C9„C10 and C17„C18),
g1 (C1„C2) liga-
l5–
g2
,
g2
,
g1
,
g1
,
– , , , ,
g2 g1 g1 g1
–
g2
, , , , g
g2 g1 g1
Fig. 7. Packing diagram of 3 viewed along b direction. The trifluoroacetate anions
containing F19 are displayed, as well as the carboxyl groups of the anions
containing C25. Other anions, hydrogen atoms and acetonitrile molecules are
omitted for clarity. Symmetry code: a x, ꢂy, z ꢂ 0.5; b x ꢂ 0.5, 0.5ꢂy, z ꢂ 0.5; c
x ꢂ 0.5, 0.5 + y, z; d x, 1 + y, z.
column and stacked via weak face-to-face
p p interactions. Each
ꢁ ꢁ ꢁ
fragment and its inversion-related neighbors share three Agꢁ ꢁ ꢁAg
edges to generate an infinite column (Fig. 8).
As shown in Fig. 6, independent atom Ag3 alone lies outside the
In both 4 and 5, CAHꢁ ꢁ ꢁX (X = Br, Cl) hydrogen bonds and weak
halogenꢁ ꢁ ꢁhalogen interactions are observed between the silver
silver basket and is anchored by type
l
4–O,O,O0,O0 (O3–O4) and
Fig. 8. Extension of silver chain in 4 (a) and 5 (b). Acetonitrile molecules and trifluoroacetate anions and a minor disordered part of Cl5/Br5 with C55 to C60 (of both) are
omitted for clarity. Selected bond lengths [Å], 4: C1„C2 1.203(8), C9„C10 1.211(9), C17„C18 1.193(9), C25„C26 1.200(9), Cꢁ ꢁ ꢁAg: 2.101(7) (C17ꢁ ꢁ ꢁAg8) to 3.022(8)
(C18ꢁ ꢁ ꢁAg7), Agꢁ ꢁ ꢁAg: 2.882(1) (Ag6ꢁ ꢁ ꢁAg6b) to 3.277(1) (Ag4ꢁ ꢁ ꢁAg10)). 5: C1„C2 1.224(16), C9„C10 1.203(16), C17„C18 1.205(16), C25„C26 1.200(15), Cꢁ ꢁ ꢁAg: 2.131(11)
(C17ꢁ ꢁ ꢁAg8) to 3.012(13) (C25ꢁ ꢁ ꢁAg8b), Agꢁ ꢁ ꢁAg: 2.883(2) (Ag6ꢁ ꢁ ꢁAg6b) to 3.262(2) (Ag3ꢁ ꢁ ꢁAg7). Symmetry code 4: a 1 ꢂ x, 2ꢂy, ꢂz; b 1 ꢂ x, 1 ꢂ y, 1 ꢂ z. 5: a 1 ꢂ x, 2 ꢂ y, 1 ꢂ z;
b 1 ꢂ x, 1 ꢂ y, 2 ꢂ z. Ring centroid-to-centroid distance in the sequence (I), (II), (III): 4, 3.844(1), 3.810(1), 4.276(1) Å; 5: 3.860(1), 3.860(1), 4.219(1), respectively.

S.M.J. Wang, T.C.W. Mak / Polyhedron 28 (2009) 2684–2692
2689
for 4, d(Br2bꢁ ꢁ ꢁC30) = 3.456(9) Å, CHBr = 132° for 5, while halo-
genꢁ ꢁ ꢁhalogen interactions are observed between the Cl or Br atom
at the meta position of the phenylethynide moiety and a fluorine
atom of the CF3COOꢂ anion: d(Cl3ꢁ ꢁ ꢁF16) = 3.195(9) Å for 4 and
d(Br3ꢁ ꢁ ꢁF16) = 3.19(1) Å for 5. Although the inter-halogen contacts
are close to the sums of their van der Waals radii, their presence
and attractive nature contribute to the stability of the network. It
is noted that in compound 3, van der Waals type Clꢁ ꢁ ꢁF interaction
also occurs between the meta chlorine atom and the fluorine atom
of a CF3COOꢂ anion.
3.5. 2AgL5 ꢁ 4AgCF3COO ꢁ NC(CH2)4CN (6) and 2AgL5 ꢁ 4AgCF3COO ꢁ
2CH3CN (7)
In the structural units of these two complexes, parallelly-related
ethynide ligands are inserted into Ag5 baskets by adopting the l5
1(C1„C2), l5 1(C9„C10) (in 6) and
1(C1„C2), l5 1(C9„C10) (in
7) ligation modes, with interactions occurring between the
ꢁ ꢁ ꢁ
–
g2
the l5
,
g2
,
g1
–
,
g1
g2
,
g
,
–
g2
,
g1
,
g1
–
,
g1
g2
,
g
g2
,
g2
,
g2
,
g
g2
,
, , , g
g1 g1
p
p
phenyl rings. The centroid-to-centroid distances are 3.928(1) Å (6,
average inter-planar distance 3.58 Å) and 3.941(2) Å (7, average in-
ter-planar distance 3.54 Å) (Figs. 10 and 11). Both silverꢁ ꢁ ꢁchloro
interaction and chloroꢁ ꢁ ꢁfluoro interaction are observed in complex
6 (Ag6ꢁ ꢁ ꢁCl1 3.191(4) Å, Ag7ꢁ ꢁ ꢁCl1 3.006(5) Å, Ag1ꢁ ꢁ ꢁCl2 3.404(1) Å,
Cl2ꢁ ꢁ ꢁF12 3.165(4) Å; Ag7 and Ag6 together represent a disordered
silver atom with site occupancy ratio Ag6:Ag7 = 13:12.). The dis-
tance between Cl1 and Ag6/Ag7 is significantly smaller than the
sum of their van der Waals radii by 0.3–0.5 Å [9], indicated a strong
silverꢁ ꢁ ꢁhalogen interaction. On the other hand, both silverꢁ ꢁ ꢁchloro
and chloroꢁ ꢁ ꢁfluoro short contacts occur at Cl2, which has never
been observed in our previous works. In 7, only silverꢁ ꢁ ꢁchloro
interaction is observed: Cl2ꢁ ꢁ ꢁAg6 3.280(3) Å, indicating a moder-
ately-strong silverꢁ ꢁ ꢁhalogen interaction.
In complex 6, two adjacent inversion-related structural units are
held by argentophilic interactions (Ag3ꢁ ꢁ ꢁAg3b and Ag5ꢁ ꢁ ꢁAg5a) to
form a silver column in the a direction (Fig. 12a), and such columns
are further expanded to a two-dimensional supramolecular struc-
ture via the linkage of adiponitrile molecules, as shown in
Fig. 13a. In 7, a silver column parallel to a axis is similarly formed
(sharing edges Ag1ꢁ ꢁ ꢁAg1b and Ag3ꢁ ꢁ ꢁAg3a) (Fig. 12b), which is ex-
panded into a three-dimensional supramolecular structure via the
formation of two hydrogen bonds: C5–H5ꢁ ꢁ ꢁF18 (C5ꢁ ꢁ ꢁF18:
Fig. 9. Weak halogenꢁ ꢁ ꢁhalogen interactions and CAHꢁ ꢁ ꢁX (X = Cl, Br) type hydro-
gen bonds in the crystal structure of 4 (a) and 5 (b). Symmetry code 4: a 2 ꢂ x, 1 ꢂ y,
1 ꢂ z; b 2 ꢂ x, 1 ꢂ y, ꢂz; 5: a 2 ꢂ x, 1 ꢂ y, 2 ꢂ z; b 2 ꢂ x, 1 ꢂ y, 1 ꢂ z.
columns, leading to a three-dimensional supramolecular architec-
ture [11–13] (Fig. 9). Hydrogen bonds occur between the halogen-
substituted phenyl rings: d(Cl2bꢁ ꢁ ꢁC30) = 3.380(8) Å, \CHCl = 126°
3.274(9) Å,
\CHF = 170°)
and
C28–H20ꢁ ꢁ ꢁO7
(C28ꢁ ꢁ ꢁO7:
3.236(12) Å, \CHO = 162°) [13], as shown in Fig. 13b.
Fig. 10. (a) Coordination geometry of complex 6 (thermal ellipsoid 50%). All trifluoroacetate ions, hydrogen labels and disordered groups are omitted for clarity. Selected
bond lengths [Å]: C1„C2 1.217(5), C9„C10 1.224(4), C1ꢁ ꢁ ꢁAg2 2.270(3), C1ꢁ ꢁ ꢁAg4 2.740(3), C1ꢁ ꢁ ꢁAg5 2.193(4), C1ꢁ ꢁ ꢁAg6 2.249(6), C1ꢁ ꢁ ꢁAg5a 2.626(3), C2ꢁ ꢁ ꢁAg6 2.602(6),
C2ꢁ ꢁ ꢁAg5a 2.916(3), C9ꢁ ꢁ ꢁAg1 2.236(5), C9ꢁ ꢁ ꢁAg2 2.748(5), C9ꢁ ꢁ ꢁAg3 2.211(3), C9ꢁ ꢁ ꢁAg4 2.285(4), C9ꢁ ꢁ ꢁAg3b 2.532(4), C10ꢁ ꢁ ꢁAg1 2.687(4), C10ꢁ ꢁ ꢁAg3b 2.772(4), Cl1ꢁ ꢁ ꢁAg6
3.191(4), Cl2ꢁ ꢁ ꢁAg1 3.404(1), Ag1ꢁ ꢁ ꢁAg3 3.093(1), Ag1ꢁ ꢁ ꢁAg4 3.299(1), Ag2ꢁ ꢁ ꢁAg3 3.190(1), Ag2ꢁ ꢁ ꢁAg4 2.919(1), Ag2ꢁ ꢁ ꢁAg5 2.810(1), Ag3ꢁ ꢁ ꢁAg3b 2.832(1), Ag3ꢁ ꢁ ꢁAg4 2.780(1),
Ag4ꢁ ꢁ ꢁAg5 3.234(1), Ag5ꢁ ꢁ ꢁAg6 3.078(3), Ag5ꢁ ꢁ ꢁAg5a 2.808(1). Symmetry code: a 1 + x, y, 1 + z; b ꢂ x, 1 ꢂ y, 1 ꢂ z. (b) Agꢁ ꢁ ꢁClꢁ ꢁ ꢁF interaction. Cl2ꢁ ꢁ ꢁF12: 3.165(4) Å.

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S.M.J. Wang, T.C.W. Mak / Polyhedron 28 (2009) 2684–2692
Fig. 11. Coordination geometry of complex
7
(thermal ellipsoid 50%). All CF3
moieties of trifluoroacetate ions, acetonitrile molecules and hydrogen labels are
omitted for clarity. Selected bond lengths [Å]: C1„C2 1.219(6), C9„C10 1.226(9),
C1ꢁ ꢁ ꢁAg1 2.167(5), C1ꢁ ꢁ ꢁAg2 2.320(5), C1ꢁ ꢁ ꢁAg4 2.580(7), C1ꢁ ꢁ ꢁAg5 2.318(6),
C1ꢁ ꢁ ꢁAg1b 2.608(5), C2ꢁ ꢁ ꢁAg2 2.982(5), C2ꢁ ꢁ ꢁAg4 2.937(7), C2ꢁ ꢁ ꢁAg5 2.850(7),
C2ꢁ ꢁ ꢁAg1b 2.959(5), C9ꢁ ꢁ ꢁAg2 2.778(7), C9ꢁ ꢁ ꢁAg3 2.180(6), C9ꢁ ꢁ ꢁAg4 2.397(6),
C9ꢁ ꢁ ꢁAg6 2.297(8), C9ꢁ ꢁ ꢁAg3a 2.599(6), C10ꢁ ꢁ ꢁAg6 2.618(8), C10ꢁ ꢁ ꢁAg3a 2.983(5),
Cl2ꢁ ꢁ ꢁAg6 3.280(3), Ag1ꢁ ꢁ ꢁAg2 2.908(1), Ag1ꢁ ꢁ ꢁAg4 3.123(2), Ag1ꢁ ꢁ ꢁAg5 2.988(2),
Ag1ꢁ ꢁ ꢁAg1b 2.862(1), Ag2ꢁ ꢁ ꢁAg3 3.160(1), Ag2ꢁ ꢁ ꢁAg4 3.011(2), Ag2ꢁ ꢁ ꢁAg5 3.236(2),
Ag3ꢁ ꢁ ꢁAg4 2.804(1), Ag3ꢁ ꢁ ꢁAg6 3.134(2), Ag3ꢁ ꢁ ꢁAg3a 2.818(1). Symmetry code: a
1 ꢂ x, 1 ꢂ y, 1 ꢂ z; b 2 ꢂ x, 1 ꢂ y, 1 ꢂ z.
3.6. AgL6ꢁ2CF2(CF2COOAg)2ꢁ2CH3CN (8)
In compound 8, the 2-fluorophenylethynide ligand is connected
Fig. 13. (a) The two-dimensional coordination network of 6. Symmetry code: a ꢂx,
1 ꢂ y, 1 ꢂ z; b 1 ꢂ x, 1 ꢂ y, ꢂz; c x ꢂ 1, y, z ꢂ 1. (b) The 3D structure of 7 constructed
by hydrogen bonds. Symmetry code: a 1 ꢂ x, 1 ꢂ y, 2 ꢂ z; b x, 1 + y, z.
to a butterfly-shaped Ag5 basket by adopting the l4– , , ,
g2 g2 g1 g1
ligation mode (Fig. 14). The lone Ag5 atom is coordinated linearly
by two acetonitrile ligands and a carboxylate oxygen atom: Agꢁ ꢁ ꢁO
(2.622(2) Å). One of the two independent hexafluoroglutarate dia-
nions adopts a bent conformation to anchor on the Ag5 basket,
while the other one is fully extended. The distance between F13
and Ag2 is 3.106(3) Å, being approximately equal to the sum of
their van der Waals radii [9].
the b direction, the Ag8 aggregates are linked by unbent hexaflu-
oroglutaric dianions to yield a two-dimensional metal–organic
network.
In this two-dimensional framework, the hexafluoroglutaric dia-
nions form a loop structure, and the void space in the middle of it is
filled by two linear Ag(CH3CN)2 moieties (NAAgAN = 169°)
oriented parallel to the c axis. The silver atom Ag5 of such a moiety
is connected to the surrounding dianions via two weak Agꢁ ꢁ ꢁO
coordination interactions (Ag5ꢁ ꢁ ꢁO5 2.622(2) Å, Ag5ꢁ ꢁ ꢁO8
By sharing one edge (Ag1ꢁ ꢁ ꢁAg1a), two inversion-related Ag5
baskets form an Ag8 aggregate.
A
halogenꢁ ꢁ ꢁ
p interaction
(Fig. 15) is observed between F3 and the centroid of the phenyl ring
belonging to an inversion-related unit (F3ꢁ ꢁ ꢁcentroid 3.292(2) Å;
closest Fꢁ ꢁ ꢁC contact F3aꢁ ꢁ ꢁC7 3.351(4) Å) [14] The centrosymmet-
ric Ag8 aggregates are further linked by bent hexafluoroglutarate
dianions to form a silver–organic chain along the a axis, in which
2.884(2) Å) and
a
CAHꢁ ꢁ ꢁF type hydrogen bond (C10ꢁ ꢁ ꢁF8
3.296(5) Å, \CHF = 155°) A close contact of 3.002(2) Å is also
observed between the ligand-unsupported Ag5 atom and F11a in
the perfluoro arm of the surrounding dianion. Although this moiety
does not serve as a bonding-linkage unit, it fills the ligand-
inaccessible void space to stabilize the overall framework structure
(Fig. 16).
each carboxyl group adopts the
l
3–O,O,O0, mode. Notably, short
Fꢁ ꢁ ꢁAg contacts are also observed between fluorine and silver
atoms of adjacent Ag8 aggregates: Ag3ꢁ ꢁ ꢁF1c 3.044(2) Å, Ag4ꢁ ꢁ ꢁF5c
2.915(2) Å (Fig. 15), being significantly shorter than the sum of
their van der Waals radii, 3.19 Å [9]. On the other hand, along
Fig. 12. (a) Formation of silver column in complex 6. Symmetry code: a 1 ꢂ x, 1 ꢂ y, 1 ꢂ z; b ꢂ x, 1 ꢂ y, 1 ꢂ z. (b) Formation of silver column in 7. Symmetry code: a 1 ꢂ x,
1 ꢂ y, 1 ꢂ z; b 2 ꢂ x, 1 ꢂ y, 1 ꢂ z. Hydrogen atoms, trifluoroacetate ions and acetonitrile/adiponitrile molecules are omitted for clarity.

S.M.J. Wang, T.C.W. Mak / Polyhedron 28 (2009) 2684–2692
2691
4. Conclusion
We have synthesised eight silver(I) halophenyl ethynide com-
plexes bearing the supramolecular synthon RX–C„CꢀAgn (n = 4,
5; RX = halophenyl). Strong silverꢁ ꢁ ꢁiodo interactions in two of the
structures play an important role in constructing high-dimensional
coordination networks, while in the other six complexes, sil-
verꢁ ꢁ ꢁchloro interactions and chloroꢁ ꢁ ꢁfluoro, bromoꢁ ꢁ ꢁfluoro inter-
actions are observed. The silverꢁ ꢁ ꢁiodo contacts in crystals are
significantly shorter than those of silverꢁ ꢁ ꢁchloro and silverꢁ ꢁ ꢁflu-
oro, indicating that the silverꢁ ꢁ ꢁiodo interaction has greater
strength, since the van der Waals radius of iodine is larger than
those of the other two (I: 198 pm, Cl: 175 pm, F: 147 pm).
It is notable that, in compound 1 and 2, the ligation mode of
ethynide ligands toward Agn baskets is l4– rather than l5–, though
the latter mode is commonly observed in our previous studies
[4b,6]. Moreover, the respective ratios of ancillary ligands to the
ethynide ligand are also smaller than expected. This is probably
due to the significant strength of the silverꢁ ꢁ ꢁiodine interaction,
Fig. 14. Coordination geometry and atom labeling of 8. Labels of hydrogen atoms
are omitted. Selected bond lengths [Å]: C1„C2 1.223(3), C1ꢁ ꢁ ꢁAg1 2.297(3),
C1ꢁ ꢁ ꢁAg2 2.513(3), C1ꢁ ꢁ ꢁAg3 2.257(2), C1ꢁ ꢁ ꢁAg4 2.301(3), C1ꢁ ꢁ ꢁAg1a 2.554(3),
C2ꢁ ꢁ ꢁAg2 2.609(3), C2ꢁ ꢁ ꢁAg1a 2.671(3), Ag1ꢁ ꢁ ꢁAg2 2.915(1), Ag1ꢁ ꢁ ꢁAg3 2.901(1),
Ag1ꢁ ꢁ ꢁAg4 2.829(1), Ag1ꢁ ꢁ ꢁAg1a 3.012(1), Ag3ꢁ ꢁ ꢁAg4 2.876(1), Ag2ꢁ ꢁ ꢁF13 3.106(3),
O5ꢁ ꢁ ꢁAg5 2.622(2). Symmetry code: a ꢂx, 1 ꢂ y, 1 ꢂ z.
the
l2–I ligation mode, and the rigidity of the iodophenyl ligand
which together account for little accessible void space for the
accommodation of ancillary ligands. A better understanding of
the role of silverꢁ ꢁ ꢁhalogen interactions on stabilization of coordi-
nation networks needs to be further investigated.
Within the limited number of complexes reported here, all
halogen atoms at the para position of the phenyl ring are observed
to form silverꢁ ꢁ ꢁhalogen interactions, while van der Waals type hal-
ogen (Cl, Br)ꢁ ꢁ ꢁfluoro interactions are observed on all substituents at
the meta position. This is an interesting phenomenon unnoticed in
the past. On the other hand, ortho chloro atoms in 6 and 7 form
moderate to strong silverꢁ ꢁ ꢁchloro interactions due to their rela-
tively close location to the silver baskets; for the same reason, they
are not involved in the generation of higher-dimensional structures.
The silverꢁꢁꢁfluoro close contacts observed in 8 are different from
the silverꢁ ꢁ ꢁchloro(ortho) interactions in 6 and 7: the strong elec-
tron-withdrawing fluoro substituent on the phenyl ring facilitates
the formation of charge-induced Fꢁ ꢁ ꢁ
p interaction. On the other
hand, though the silverꢁ ꢁ ꢁfluoro interaction that involves contacts
significantly shorter than the sum of respective van der Waals radii
is not well-recognized due to too few reports in the literature, the
occurrence of unusually large number of such contacts in one
structure indicated its potentially significant role in the stabiliza-
tion of coordination networks.
Fig. 15. The bridging linkage of Ag8 clusters in 8 along the a direction. Acetonitrile
molecules, Ag5 and the unbent hexafluoroglutarate anion are omitted for clarity.
Symmetry code: a ꢂx, 1 ꢂ y, 1 ꢂ z; b x ꢂ 1, y, z; c 1 ꢂ x, 1 ꢂ y, 1 ꢂ z .
The present report demonstrates the feasibility of using halo-
gen-substituted phenylethynide synthons RX–C„CꢀAgn (n = 4, 5)
in the construction of silver(I) coordination and supramolecular
networks. Variation on the type and the position of halogen sub-
stituents on the phenyl ring leads to network structures of differ-
ent dimensionality due to the presence of subtle weak
interactions in supramolecular organization. Further systematic
investigation employing multi-substituted halophenylethynide li-
gands is required in order to shed additional light on the role of
weak supramolecular interactions involving halogen atoms in the
stabilization of coordination networks.
Acknowledgment
This work is supported by the Hong Kong Research Grants
Council (GRF CUHK 402408) and the Wei Lun Foundation of The
Chinese University of Hong Kong.
Appendix A. Supplementary data
CCDC 723285, 723286, 723287, 723288, 723289, 723290,
723291 and 723292 contain the supplementary crystallographic
Fig. 16. Packing diagram of complex 8. Symmetry code: a 1 ꢂ x, ꢂy, 1 ꢂ z; b ꢂ x, ꢂy,
1 ꢂ z; c 1 + x, y, z.

2692
S.M.J. Wang, T.C.W. Mak / Polyhedron 28 (2009) 2684–2692
(e) S.-Q. Zang, L. Zhao, T.C.W. Mak, Organometallics 27 (2008) 2396;
(f) L. Zhao, X.-D. Chen, T.C.W. Mak, Organometallics 27 (2008) 2483;
(g) S.-Q. Zang, T.C.W. Mak, Inorg. Chem. 47 (2008) 7094;
(h) L. Zhao, C.-Q. Wan, J. Han, X.-D. Chen, T.C.W. Mak, Chem. Eur. J. 14 (2008)
10437.
data for this paper. These data can be obtained free of charge via
http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail: de-
posit@ccdc.cam.ac.uk. Supplementary data associated with this
article can be found, in the online version, at doi:10.1016/
j.poly.2009.05.004.
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