Assembly of layer-type organosilver(i) complexes incorporating nitrate and isomeric halophenylethynide ligands

Article abstract of DOI:10.1071/CH14326

Single-crystal X-ray analysis of a series of 10 silver(I) nitrate complexes containing carbon-rich ligands each composed of a halosubstituted phenyl nucleus bearing a terminal ethynyl group at various positions provided detailed information on the influen

Full text of DOI:10.1071/CH14326

RESEARCH FRONT
CSIRO PUBLISHING
Aust. J. Chem.
Full Paper
http://dx.doi.org/10.1071/CH14326
Assembly of Layer-Type Organosilver(I) Complexes
Incorporating Nitrate and Isomeric Halophenylethynide
Ligands
A
A
A B
,
Ping-Shing Cheng, Sam C. K. Hau, and Thomas C. W. Mak
A
Department of Chemistry and Center of Novel Functional Molecules, The Chinese
University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China.
Corresponding author. Email: tcwmak@cuhk.edu.hk
B
Single-crystal X-ray analysis of a series of 10 silver(I) nitrate complexes containing carbon-rich ligands each composed of
a halosubstituted phenyl nucleus bearing a terminal ethynyl group at various positions provided detailed information on
the influence of ligand disposition and orientation, coordination preferences, and the co-existence of silver(I)–ethynide and
silver(I)–halogen interactions in the construction of coordination networks, which are consolidated by argentophilic and
weak intra or intermolecular interactions.
Manuscript received: 22 May 2014.
Manuscript accepted: 23 July 2014.
Published online: 3 September 2014.
Introduction
and (o-IC6H4CꢀCAg)2ꢂAgNO3ꢂDMSO (9). On the basis
of our previous experience, dissolution of the crude starting
materials [p-ClC6H4CꢀCAg]n (10), [p-BrC6H4CꢀCAg]n
(11), [p-IC6H4CꢀCAg]n (12), [m-ClC6H4CꢀCAg]n (13), [m-
BrC6H4CꢀCAg]n (14), [m-IC6H4CꢀCAg]n (15), [o-ClC6H4Cꢀ
CAg]n (16), [o-BrC6H4CꢀCAg]n (17), and [o-IC6H4CꢀCAg]n
(18) in a concentrated DMSO solution of silver nitrate is
expected to generate MOFs stabilized by argentophilic, multi-
nuclear silver(I)–ethynide bonding and silver–halogen inter-
actions, and the phenyl ring is potentially capable of partaking
in weak p–p stacking interactions.
Coordination polymers are potential precursors for the synthesis
of photoluminescent materials,[1] non-linear optical compo-
nents,[2] and rigid-rod molecular wires.[3] Such polymers are
often derived from transitional metal–ethynyl complexes,[4–6]
which are regarded as structure building units (SBUs) owing to
their occurrence and structural diversity. In the past decades, our
group and others have made use of the silver(I)-ethynide[7]
supramolecular synthon[8] R–CꢀCꢁAgn (R ¼ alkyl, phenyl,
heteroaryl, n ¼ 3–5) as a versatile and robust SBU in the gen-
eration of various high-nuclearity clusters,[9–11] as well as a wide
variety of two- and three-dimensional metal–organic frame-
works (MOFs).[11,12]
Results and Discussion
Several years ago, we reported a systematic study on new
silver(I) trifluoroacetate complexes containing ligands each
composed of a halophenyl nucleus functionalized with a termi-
nal ethynide group, which exhibit a wide variety of crystal
structures consolidated by silver–ethynide and silver–halogen
interactions.[13] Subsequent investigation of silver(I) complexes
generated with aromatic ligands bearing a terminal ethynide
substituent showed that crystallization in DMSO in the presence
of nitrate ions led to the assembly of argentophilic layer-type
structures.[8,14] To extend our systematic investigation in this
area, we focussed our attention on the utility of halophenyl-
ethynide ligands in combination with nitrate ions for crystalli-
zation in DMSO.
The polymeric powdery materials [p-ClC6H4CꢀCAg]n (10),
[p-BrC6H4CꢀCAg]n (11), [p-IC6H4CꢀCAg]n (12), [m-
ClC6H4CꢀCAg]n (13), [m-BrC6H4CꢀCAg]n (14), [m-IC6H4Cꢀ
CAg]n (15), [o-ClC6H4CꢀCAg]n (16), [o-BrC6H4CꢀCAg]n (17),
and [o-IC6H4CꢀCAg]n (18) were synthesized from the reaction
between the corresponding halosubstituted phenylethynide
compounds and silver nitrate in the presence of triethylamine.
These precursors were then each dissolved in a concentrated
DMSO solution of AgNO3 to increase the silver(I) ion con-
centration and provide the auxiliary NOꢃ3 ligand, which are
necessary for the formation of the R–CꢀCꢁAgn supramolecular
synthon, where n can be as high as 4 or 5.[15,16]
Herein, we report the synthesis of a series of 10 new
polymeric silver(I) halosubstituted phenyl ethynides, from
which 10 crystalline complexes have been generated with the
incorporation of nitrate: (p-ClC6H4CꢀCAg)2ꢂAgNO3 (1),
(p-BrC6H4CꢀCAg)2ꢂAgNO3 (2), (p-IC6H4CꢀCAg)2ꢂAgNO3
(3A and 3B), (m-ClC6H4CꢀCAg)2ꢂAgNO3 (4), (m-BrC6H4Cꢀ
CAg)2ꢂAgNO3 (5), (m-IC6H4CꢀCAg)2ꢂAgNO3ꢂH2O (6), (o-
ClC6H4CꢀCAg)2ꢂAgNO3 (7), (o-BrC6H4CꢀCAg)3ꢂAgNO3 (8),
Description of Crystal Structures
(p-ClC6H4CꢀCAg)2ꢂAgNO3 (1)
Complex 1 contains two crystallographically independent
ethynide ligands that exhibit different coordination modes:
m4–Z1,Z1,Z2,Z2 for C1ꢀC2 and m3–Z1,Z1,Z2 for C9ꢀC10
(Fig. 1a). Silver(I) ions Ag2 and Ag3, and their inversion-related
equivalents Ag2A andAg3A constitute a pyramidal Ag4 segment.
Journal compilation Ó CSIRO 2014
www.publish.csiro.au/journals/ajc

B
P.-S. Cheng, S. C. K. Hau, and T. C. W. Mak
(a)
C13
(b) c
C12
C12
b
C14
C11
Ag3B
Ag2
C9
C15
II
a
C10
Ag1A
Ag3B
C16
Ag1A
Ag1
Ag2
Ag3
Ag2C
C2
N1
O2
Ag3
C1
O3
Ag1
Ag2C
I
O1
C4
Ag3A
Ag1D
Ag2D
C3
C8
C5
C6
Cl1
C7
Fig. 1. (a) Perspective view of coordination geometry in double salt (p-ClC6H4CꢀCAg)2ꢂAgNO3 (1). The argentophilic AgꢂꢂꢂAg distances
˚
shown as thick rods lie in the range 2.70–3.40 A. Silver ions are drawn as thermal ellipsoids (50 % probability level) with atom labelling.
(b) Perspective view of silver(I) layer viewed along the c axis. Symmetry codes: A: 2x, 2y, 1 2 z, B: 1 2 x, ꢃy, 1 2 z, C: 1 ꢃ x, 1 ꢃ y, 1 ꢃ z,
D: 1 þ x, y, z. In this and all other figures, silver ions coordinated by independent ethynide ligands are shown in purple, and other symmetry-
related silver ions are drawn in blue; the hydrogen and fluorine atoms are omitted for clarity.
(a)
a
(b)
Ag1C
b
IIٞ
c
IIЉ
Ag3B
Ag2A
IЉ
Ag2
I
Ag3
Ag1
Ag1
Ag3B
Ag2C
II
Ag1A
Ag2
IIЉ
Fig. 2. (a) Perspective view of silver(I) layer in 1 along the b axis. (b) Perspective view of the crystal packing in 1, showing all notable
p–p stacking interactions. Symmetry codes: A: 2x, 2y, 1 2 z, B: 1 þ x, y, z, C: 1 ꢃ x, 1 ꢃ y, 1 ꢃ z, D: x, 1 þ y, z, E: 1 þ x, 1 þ y, z.
Such segments are linked through argentophilic interaction
between type Ag2 ions to generate an infinite silver(I) chain
along the b axis. Adjacent chains are further associated by Ag1
ions to yield a wavy layer structure (Fig. 1b and Fig. 2a).
In addition, each argentophilic layer is flanked on both sides
by 4-chlorophenyl rings, which exhibit continuous offset face-
to-face p–p stacking interactions (inter-centroid distance: ring
Such units are then fused together through argentophilic
interaction to yield a silver(I) layer (Fig. 4a). Adjacent phenyl
rings of p-IC6H4CꢀCꢃ ligands arranged on both sides of the
silver(I) layer are held tightly through both offset face-to-
face p–p stacking (inter-centroid distance: ring II?ring III0,
00
000
˚
˚
3.884(2) A; ring IV ?ring I , 3.978(2) A) and edge-to-face
C–H?p interactions (C16–H?ring I0000, 2.735(2) A with an
˚
0
00
00
˚
˚
˚
I?ring II , 3.915(2) A; ring I?ring II , 3.839(2) A) (Fig. 2b).
angle of 134.88; C20B–H?ring IV , 2.744(2) A with an angle
of 128.98) (Fig. 4b).
(p-BrC6H4CꢀCAg)2ꢂAgNO3 (2) and
(m-BrC6H4CꢀCAg)2ꢂAgNO3 (5)
(p-IC6H4CꢀCAg)2ꢂAgNO3 (3B)
Complexes 2 and 5 were found to be isomorphs of the
corresponding chlorosubstituted phenylethynide complexes 1
and 4 respectively, and their crystal structures are reported in the
Supplementary Material.
Unlike 3A, which was crystallized from slow diffusion
by water layering over a DMSO filtrate, complex 3B was
obtained from slow evaporation of a saturated solution of
p-IC6H4CꢀCAg (12) with AgNO3 (3 mmol) in acetonitrile.
Complex 3B belongs to the higher-symmetry space group P4/
mcc. The independent p-IC6H4CꢀCꢃ ligand is attached to
independent silver(I) ions Ag1 and Ag2 in the m3–Z1,Z1,Z2
coordination mode (Fig. 5a), in which Ag2 exhibits half-site
occupancy. With a two-fold axis passing through the centre of
Ag1, an infinite silver(I) chain is generated along the c axis,
which is consolidated by the nitrate ligand adopting the m2-O,O0
mode (Fig. 5b).
(p-IC6H4CꢀCAg)4ꢂ(AgNO3)2 (3A)
The asymmetric unit of 3A contains six crystallographically
independent AgI ions, four ethynide ligands in different ligation
modes, and two bridging nitrate ligands in m3–Z1,Z3 and
m3–Z1,Z2 modes. The four independent ethynide groups
(C1ꢀC2, C9ꢀC10, C17ꢀC18, C25ꢀC26) are inserted to sepa-
rate Ag3 units in either m3–Z1,Z2,Z2 or m3–Z1,Z1,Z2 modes
(Fig. 3a, b). The independent silver(I) ions coalesce to yield an
Ag6 cluster unit.
Furthermore, adjacent silver(I) chains are interassociated
[13]
through a notable Ag?I interaction (I1?Ag1B, 3.586(9) A)
˚

Silver Complexes Bearing Nitrate and Halophenylethynide
C
O5
(a)
N2
O6
(b)
Ag6C
O4
C31
I4
C32
C26 C27
C25
Ag5
Ag1A
Ag3B
II
Ag6
C30
I2
IV
C13
C12
C11
C29
C14
Ag4
C9
C28
C20
Ag4
C15
C10
C16
C4
Ag3
I3
C21
Ag5
Ag3
C1
C5
C19
C18
Ag1A
C22
C23
I1
Ag2
C6
C2
Ag2
C17
Ag6D
C24
III
O1
O3
C3
I
C7
C8
Ag1
N1
O2
Fig. 3. (a) Perspective view of coordination geometry of two independent ligands in double salt (p-IC6H4CꢀCAg)4ꢂ(AgNO3)2 (3A). The
˚
argentophilic AgꢂꢂꢂAg distances shown as thick rods lie in the range 2.70–3.40A. Silver ions are drawn as thermal ellipsoids (50 %
probability level) with atom labelling. (b) Perspective view of the remaining ligands in 3A. Symmetry codes: A: 0.5 þ x, 0.5 2 y, 1 2 z,
B: 1 þ x, y, z, C: 0.5 þ x, 1.5 ꢃ y, 1 ꢃ z, D: ꢃ0.5 þ x, 1.5 ꢃ y, 1 ꢃ z.
(a)
(b)
c
c
a
b
Iٞ
II
b
a
IIIЈ
C20B
IVЉ
Ag1
IЉЉ
Ag1A
Ag3
C16
Ag4
Ag6
Ag2
Ag5
Ag6D
Fig. 4. (a) Perspective view of silver(I) layer in 3A. (b) Perspective view of the crystal packing in 3A, showing all notable p–p stacking and
CꢃHꢂꢂꢂp interactions. Symmetry codes: A: 0.5 þ x, 0.5 2 y, 1 2 z, B: 0.5 þ x, 1.5 ꢃ y, 1 ꢃ z.
(a)
(b)
O2
O1
c
N1
O1B
Ag2
b
a
Ag2A
Ag1
Ag2A
Ag1
C8
Ag2C
C7
C6
Ag2
Ag1D
C1
C2
C3
I1
C4
C5
Fig. 5. (a) Perspective view of coordination geometry in double salt (p-IC6H4CꢀCAg)2ꢂAgNO3 (3B). The argentophilic AgꢂꢂꢂAg
˚
distances shown as thick rods lie in the range 2.70–3.40 A. Silver ions are drawn as thermal ellipsoids (50 % probability level) with
atom labelling. (b) Perspective view of the infinite silver(I) chain in 3B. Symmetry codes: A: ꢃx, y, 0.5 þ z, B: ꢃx, y, 0.5 ꢃ z, C: ꢃx,
1 ꢃ y, z, D: x, 1 ꢃ y, 0.5 ꢃ z.
to yield a porous three-dimensional coordination network
(Fig. 6a), which is further stabilized by offset face-to-face
p–p stacking interaction between phenyl rings (inter-centroid
After exclusion of the van der Waals radii of the surface
atoms, the free area of the nearly circular cross-section of each
2
˚
˚
channel (radius 3.49 A) in 3B is ,12.2p A (Fig. 6b). A
calculation with PLATON reveals that the free volume of the
˚
distance: 3.743(7) A).

D
P.-S. Cheng, S. C. K. Hau, and T. C. W. Mak
(a)
(b)
b
b
a
c
a
C2A
C1A
I1A
C1
6.99 Å
I1
Ag1B
C2
Fig. 6. (a) Perspective view of the interconnection between adjacent silver(I) chains of 3B, showing all notable AgꢂꢂꢂI
interactions and p–p stacking interactions. (b) Perspective view of the porous three-dimensional coordination network,
showing a cross-section of the empty channel. Symmetry codes: A: x, y, 0.5 ꢃ z, B: x, 1 ꢃ y, z.
(a)
C5
C6
C7
I
(b)
b
C4
c
a
C3
C8
Ag3D
Ag3
Cl1
C2
Ag1A
Ag3
Ag3B
Ag2A
Ag2
Ag2A
C1
O2
Ag1
Ag3A
Ag1
Ag3B
Ag1C
C9
Ag2
C10
Ag1C
N1
O1
C16 II
C15
C11
O3
C12
C13
Ag3C
CI2
C14
Fig. 7. (a) Perspective view of coordination geometry in double salt (m-ClC6H4CꢀCAg)2ꢂAgNO3 (4). The argentophilic AgꢂꢂꢂAg distances
˚
shown as thick rods lie in the range 2.70–3.40 A. Silver ions are drawn as thermal ellipsoids (50 % probability level) with atom labelling.
(b) Perspective view of the argentophilic silver(I) layer in 4. Symmetry codes: A: ꢃx, ꢃy, 1 ꢃ z, B: ꢃx, 1 ꢃ y, 1 ꢃ z, C: 1 ꢃ x, 1 ꢃ y, 1 ꢃ z,
D: ꢃ1 ꢃ x, ꢃy, 1 ꢃ z.
(a)
c
(b)
a
b
IЉ
Ag3A
Ag2A
Ag1A
O2
O3
IIЉ
II
Ag1
Ag2
Ag2
Ag1 O1
I
Ag3
IЈ
a
IIЈ
c
Fig. 8. (a) Perspective view of coordination geometry of the nitrate ligands in 4. (b) Perspective view of the argentophilic layer in 4
along the b axis, showing all notable p–p stacking interactions. Symmetry code: A: ꢃx, ꢃy, 1 ꢃ z.
3
˚
channels is 302 A per unit cell. However, no cocrystallized
solvent molecule was found within the crystal lattice.
C9ꢀC10 (Fig. 7a). An infinite zigzag silver(I) chain is formed
along the b axis through argentophilic interaction between Ag2
and Ag2A. Such chains are interconnected by weak Ag?Ag
interaction between Ag1A and Ag3D (3.421(6) A) along the
a axis to generate an argentophilic layer (Fig. 7b).
˚
(m-ClC6H4CꢀCAg)2ꢂAgNO3 (4)
Complex 4 is isostructural with isomeric complex 1, both
belonging to the same space group P1 (no. 2) with very similar
unit cell dimensions and matching atomic coordinates. The two
independent ethynide moieties exhibit different coordination
modes: m4–Z1,Z1,Z2,Z2 for C1ꢀC2 and m3–Z1,Z1,Z2 for
This layer structure is consolidated by nitrate ligands in
m3–Z1,Z2 mode (Fig. 8a) and is further stabilized by continuous
offset face-to-face p–p stacking interaction between phenyl
0
˚
rings (inter-centroid distance: ring I?ring II , 3.804(3) A;
ring I?ring II , 4.107(3) A) (Fig. 8b).
00
˚

Silver Complexes Bearing Nitrate and Halophenylethynide
E
(a)
(b)
b
I2
C13
Ag4
Ag3A
Ag3
a
Ag2
C12
Ag2C
C9
Ag1
C1
C10
C14
C11
Ag3A
Ag2
C16 C15
II
Ag4
Ag1
Ag4C
Ag1C
C2
C3
C8
O1
N1
C4
I
Ag3
I1
O2
O1W
O3
Ag2B
C5
C6
Ag3B
C7
Fig. 9. (a) Perspective view of coordination geometry in double salt (m-IC6H4CꢀCAg)2ꢂAgNO3ꢂH2O (6). The argentophilic AgꢂꢂꢂAg
˚
distances shown as thick rods lie in the range 2.70–3.40 A. Silver ions are drawn as thermal ellipsoids (30 % probability level) with atom
labelling. (b) Perspective view of infinite silver(I) chain in 6. Symmetry codes: A: x, ꢃ1 þ y, z, B: 2 ꢃ x, y, 1.5 ꢃ z, C: x, 1 þ y, z.
c
(a)
(b)
a
IIЉ
IIٞ
IЈ
I
Ag1A
O3WD
N1C
O3C
O3E
N1E
I1
O1W
IIЈ
II
I2
Ag4B
b
c
a
Fig. 10. (a) Perspective view of crystal packing in 6, showing all notable p–p stacking interactions. (b) Perspective view of the crystal packing
showing all notable H-bonding between aqua ligands and nitrate groups between coordination layers. Symmetry codes: A: 2 ꢃ x, 2 ꢃ y, 1 ꢃ z,
B: 2 ꢃ x, 1 ꢃ y, 2 ꢃ z, C: 1.5 ꢃ x, 0.5 þ y, 1.5 ꢃ z, D: 1.5 ꢃ x, 2.5 ꢃ y, 1 ꢃ z, E: x, 2 ꢃ y, ꢃ0.5 þ z.
(m-IC6H4CꢀCAg)2ꢂAgNO3ꢂH2O (6)
Adjacent silver(I) columns are assembled in a pseudo-
hexagonal array (Fig. 12a) and interconnected through additional
˚
In the crystal structure of complex 6, two independent
m-IC6H4CꢀCꢃ ligands are coordinated to a W-shaped Ag5 unit,
in which C1ꢀC2 and C9ꢀC10 adopt m3–Z1,Z2,Z2 and
m3–Z1,Z1,Z2 modes respectively (Fig. 9a). With a two-fold axis
passing through type Ag1 and Ag4 ions, the W-shaped Ag5 units
are fused through atom sharing to generate an infinite chain of
linked parallelograms along the b axis (Fig. 9b).
H-bonding (C5–H?O3B, 2.69(5) A) to yield
dimensional supramolecular network (Fig. 12b), which is
a three-
further stabilized by weak Ag?Cl interactions (Ag3D?
˚
˚
Cl1C, 3.373(2) A, Ag2?Cl2, 3.178(2) A).
(o-BrC6H4CꢀCAg)3ꢂAgNO3 (8)
Adjacent chains are linked by weak Ag?I interactions (I1?
In complex 8, there are three independent ethynide ligands
coordinated to an Ag7 unit (comprising an Ag1–Ag4 segment
and symmetry-related silver ions Ag2A, Ag2C, and Ag3B)
in different coordination modes: m3–Z1,Z1,Z2 for C1ꢀC2,
m3–Z1,Z2,Z2 for C9ꢀC10, and m3–Z1,Z1,Z1 for C17ꢀC18
(Fig. 13a). Two inversion-related Ag4 segments are fused to
yield an Ag8 rhombic prism. With successive inversion
centres located between silver atom pairs (Ag3A and
Ag3B), adjacent Ag8 prisms are interconnected through
˚
˚
Ag1A, 3.49(2) A and I2?Ag4B, 3.50(1) A) to generate a layer
structure, which is further stabilized by continuous offset face-
to-face p–p stacking interaction between phenyl rings (inter-
0
00
˚
centroid distance: ring I?ring II , 3.852(8) A; ring I?ring II ,
˚
3.857(8) A) (Fig. 10a). Cross-linkage of adjacent metal–organic
layers through additional H-bonding between nitrate groups
˚
and aqua ligands (O1W?O3C, 2.97(3) A) yields a 3D supra-
molecular network (Fig. 10b).
˚
a double argentophilic link (Ag4?Ag3B, 3.237(7) A) to
produce an infinite silver(I) chain of polyhedra along the a
axis (Fig. 13b).
(o-ClC6H4CꢀCAg)2ꢂAgNO3 (7)
In complex 7, there are two independent ethynide moieties,
each bonded to an Ag3 triangle via the m3–Z1,Z2,Z2 mode, which
are fused to an Ag5 assembly by sharing the Ag3 atom (Fig. 11a).
The independent nitrate ion is coordinated to the silver segment
in the m4–Z1,Z1,Z2 mode. Such Ag5 segments coalesce to form
an infinite silver column along the a axis (Fig. 11b).
Each silver–ethynide coordination chain is further stabi-
lized by continuous offset face-to-face p–p stacking inter-
action between adjacent phenyl rings of two 0independent
˚
ethynides (inter-centroid distances: ring I?ring II , 3.895(2) A;
00
˚
ring II?ring I , 3.989(2) A) (Fig. 14a). Subsequently, adjacent

F
P.-S. Cheng, S. C. K. Hau, and T. C. W. Mak
C14
C13
(a)
(b)
C15
C16
C6
C7
C8
C12
Cl2
C5
C4
C11
C10
Ag2
Ag3
Ag2B
Ag1A
C3
C9
Ag1
Cl1
C2
Ag2B
Ag3C
Ag2
O2
C1
Ag3
b
a
c
Ag1A
O3
Ag1
Ag1C
N1
Ag2D
O1
Fig. 11. (a) Perspective view of coordination geometry in double salt (o-ClC6H4CꢀCAg)2ꢂAgNO3 (7). The argentophilic AgꢂꢂꢂAg
˚
distances shown as thick rods lie in the range 2.70–3.40 A. Silver ions are drawn as thermal ellipsoids (50 % probability level) with atom
labelling. (b) Perspective view of infinite silver column coordinated by o-chlorophenylethynide ligands on both sides. Symmetry codes:
A: 1 ꢃ x, ꢃy, 2 ꢃ z, B: ꢃ1 þ x, y, z, C: 1 þ x, y, z, D: 2 ꢃ x, ꢃy, 2 ꢃ z.
(a)
(b)
b
b
a
c
c
O3B
C5
Cl2
Ag2
C5C
Cl1C
O3A
Ag3D
Fig. 12. (a) Perspective view of the pseudo-hexagonal array of the infinite columns in 7 along the a axis, showing all notable H-bonding
interactions. (b) Perspective view of interconnection of adjacent chains in 7. Symmetry codes: A: ꢃ1 þ x, y, z, B: 2.5 ꢃ x, 0.5 þ y, 1.5 ꢃ z,
C: 1.5 ꢃ x, ꢃ0.5 þ y, 1.5 ꢃ z, D: 0.5 ꢃ x, ꢃ0.5 þ y, 1.5 ꢃ z.
Ag2C
Ag4B
(a)
(b)
Ag2B
Ag3B
a
b
c
II
C9
Ag3B
C10
Ag2C
Br2
Ag1
Ag2
Ag3
Ag4
Ag4
Ag3A
Ag2A
Br3
Ag4A
C17
C18
Ag1
Ag2
Ag1A
Ag2A
Br1
C2 C1
III
Ag3
I
Fig. 13. (a) Perspective view of coordination geometry in double salt (o-BrC6H4CꢀCAg)3ꢂAgNO3 (8). The argentophilic AgꢂꢂꢂAg
˚
distances shown as thick rods lie in the range 2.70–3.40 A. Silver ions are drawn as thermal ellipsoids (50 % probability level) with atom
labelling. (b) Perspective view of the infinite chain of linked polyhedra in 8. Symmetry codes: A: ꢃx, 1 ꢃ y, 1 ꢃ z, B: 1 þ x, y, z, C: 1 ꢃ x,
1 ꢃ y, 1 ꢃ z.
˚
polyhedral silver(I) columns are linked by p–p stacking
involving the0 third 00independent ethynide (inter-centroid dis-
(C5B–H?O2A, 2.94(7) A), which is further stabilized by
˚
Ag?Br interaction (Ag2A?Br1A, 3.23(7) A; Ag4C?
˚
Br2C, 3.54(7) A) to construct a 3D supramolecular network
(Fig. 14b).
˚
tance: ring III ?III , 3.706(2) A), hydrogen bonding between
the nitrate ions and the phenyl ring of o-BrC6H4CꢀCꢃ ligands

Silver Complexes Bearing Nitrate and Halophenylethynide
G
(a)
(b)
b
a
IIЉ
I
IIЈ
III
O2
c
Br2C
Ag4C
IIIЈ
O2A
C5B
O2B
C5A
IIIЉ
b
Br1A
Ag2A
a
II
IЈ
IЉ
c
Fig. 14. (a) Perspective view of the crystal packing in 8, showing continuous p–p stacking interactions. (b) Perspective view of the crystal
packing in 8, showing all notable H-bonding. Symmetry codes: A: x, ꢃ1 þ y, z, B: ꢃx, ꢃy, ꢃz, C: 1 ꢃ x, 1 ꢃ y, 1 ꢃ z.
(a)
(b)
a
C6
C7
O3
N1
I
C5
C4
C8
O1
O2
c
O2
C3
C2
Ag4A
Ag4
O3
N1
Ag4
C10
Ag3
Ag1
C1
O1
C9
Ag1
I1
Ag2
II
I2
Ag2
Ag4A
Ag3
S1
C18
C12
C11
C16
O4
C13
C14
C17
C15
Fig. 15. (a) Perspective view of coordination geometry in double salt (o-IC6H4CꢀCAg)2ꢂAgNO3ꢂDMSO (9). The argentophilic AgꢂꢂꢂAg
˚
distances shown as thick rods lie in the range 2.70–3.40 A. Silver ions are drawn as thermal ellipsoids (50 % probability level) with atom
labelling. (b) Perspective view of the wide silver(I) ribbon in 9. Symmetry code: A: ꢃ1 þ x, y, z.
(o-IC6H4CꢀCAg)2ꢂAgNO3ꢂDMSO (9)
As illustrated in Fig. 15a, both ethynide moieties of the two
independent ligands are each attached to an Ag3 basket in
m3–Z1,Z1,Z2 coordination mode. These two Ag3 segments
O1C
coalesce to produce an Ag5 aggregate through sharing one silver
atom, Ag3. With successive centres lying on silver ions Ag1 and
Ag2, such Ag5 aggregates are fused to form a wide silver(I)
ribbon consisting of three strands along the a axis (Fig. 15b),
which is further consolidated by m2-coordinated nitrate and
m2-coordinated DMSO ligands.
C17D
IЈ
IЉ
C17
O1B
N1B
In addition, adjacent silver(I) ribbons are linked through
weak H-bonding between nitrate and DMSO ligands
C17A
b
c
˚
I
(C17A–H?O1B, 2.68(2) A) to form a supramolecular layer
structure (Fig. 16). Such layers are interconnected by offset
face-to-face p–p stacking int0eractions between phenyl rings
Fig. 16. Perspective view of crystal packing in 9, showing all notable
H-bonding and p–p stacking interactions. Symmetry codes: A: 1 ꢃ x, ꢃy,
1 ꢃ z, B: x, ꢃ1 þ y, 1 þ z, C: x, y, 1 þ z, D: 1 ꢃ x, 1 ꢃ y, 1 ꢃ z.
00
˚
(inter-centroid distance: ring I ?II , 3.793(2) A). As a result,
a complex, three-dimensional silver(I) organic supramolecular
network structure is constructed.
and 5 (Fig. 17). With the terminal ethynide and halosubstituent
having a para relationship, the size difference between bromo
and chloro groups is not sufficient to influence layer-structure
construction in 1 and 2. On switching to the sterically bulky
iodo substituent in complex 3A, a more closely packed three-
dimensional coordination network is obtained.
Similarly, the layer structures of 4 and 5 based on meta-
XC6H4CꢀCꢃ ligands (X ¼ Cl, Br respectively) do not differ
much on comparison. In addition, formation of an infinite
coordination chain becomes more favourable as the
Structure Correlation Relationship
The series of 10 complexes reported herein reaffirms the
general utility of the silver–ethynide supramolecular synthon
R–CꢀCꢁAgn (n ¼ 4, 5) in coordination network assembly.
Except for 3B, which exists as a three-dimensional porous
coordination network, all complexes were crystallized from
slow liquid diffusion of deionized water into the respective
DMSO filtrate. Silver(I)-layer formation is facilitated by
multinuclear Ag–C and argentophilic interactions in 1, 2, 3A, 4,

H
P.-S. Cheng, S. C. K. Hau, and T. C. W. Mak
Cl
Br
I
para
(1)
(2)
(3A)
meta
ortho
(4)
(7)
(5)
(8)
(6)
(9)
Fig. 17. Argentophilic silver(I) structures in complexes 1–9, except 3B.
halosubstituent of the phenylethynide is changed to the iodo
group in 6. However, when the terminal ethynide and halosub-
stituent are positioned close to each other, silver–chloro and
silver–bromo interactions occur in 7 and 8 respectively, whereas
no silver–iodo interaction is found in 9 owing to steric hin-
drance. Consequently, silver(I) columnar structures are found in
7 and 8 in contrast to the ribbon in 9.
Single-crystal X-ray analysis of the complexes provided
detailed information on the influence of ligand disposition
and orientation, coordination preferences, and co-existence of
different kinds of silver(I)–ethynide and silver(I)–halogen
interactions in coordination network construction, as well as the
roles played by weak interactions in supramolecular assembly.
Experimental
Weak Intermolecular Interactions and Formation
of Supramolecular Frameworks
Materials and General Methods
(4-Iodophenylethynyl)trimethylsilane, (3-iodophenylethynyl)
trimethylsilane, (2-iodophenylethynyl)trimethylsilane, (4-
bromophenylethynyl)trimethylsilane, (3-bromophenylethynyl)
trimethylsilane, (2-bromophenylethynyl)trimethylsilane, 4-
chlorophenyl acetylene, 3-chlorophenyl acetylene, and 2-
chlorophenyl acetylene were obtained commercially from Farco
Chemical Supplies or Aldrich and used without further purifi-
cation. Organic solvents were removed under reduced pressure
on a rotary evaporator. Chromatographic purification of the
products was performed on Macherey Nagel Kieselgel 60M
(230–400 mesh). Thin-layer chromatography (TLC) was con-
ducted on Merck silica gel 60 F254 (0.1-mm thickness) coated on
aluminium plates. Melting points (uncorrected) were measured
with a Reichert apparatus in degrees Celsius. Elemental analysis
(C, H, N) was performed at Shanghai Institute of Organic
Chemistry, China.
Among the 10 complexes reported herein, DMSO is only found
as a cocrystallized solvent molecule in complex 9. This result
reflects the dominant coordination capacity of the nitrate ion,
which plays a major role in directing two-dimensional argen-
tophilic assembly. The coordination modes of the nitrate groups
vary from the common m3–Z1,Z2 kind to the m2–Z1,Z1 and
m4–Z1,Z1,Z2 varieties. The nitrate ligand generally plays two
important roles: one type spans an edge of the Agn basket to
consolidate the [AgnCꢀC](nꢃ1)þ cationic moiety, whereas the
other type bridges adjacent Agn baskets or Ag ions to generate an
infinite chain or a layer-type structure.
In complexes 1–5, the offset face-to-face p–p stacking
interactions and edge-to-face C–H?p interactions play signif-
icant roles in stabilizing the argentophilic silver(I) layers. In 6, 8,
and 9, aromatic p–p stacking interaction between adjacent
layers leads to the generation of a three-dimensional supra-
molecular network. When the terminal ethynide (C1ꢀC2) is
positioned closer to the chloro group (7), the stronger Ag?Cl
interaction dominates formation of the assembled structure at
the expense of weak p–p stacking interactions.
CAUTION! Silver ethynide complexes are potentially
explosive and should be handled with extreme care and used
in small quantities.
Preparation of Polymeric Silver Salts as Synthetic
Precursors
Hydrogen bonding between the nitrate group and the aqua
ligand in 6, or weak C–HꢂꢂꢂO interaction (7–9) with the phenyl
ring confer enhanced stability to the silver(I) coordination chains
and connect them into a two- or three-dimensional supra-
molecular network.
[p-ClC6H4CꢀCAg]n (10), [p-BrC6H4CꢀCAg]n (11),
[p-IC6H4CꢀCAg]n (12), [m-ClC6H4CꢀCAg]n (13),
[m-BrC6H4CꢀCAg]n (14), [m-IC6H4CꢀCAg]n (15),
[o-ClC6H4CꢀCAg]n (16), [o-BrC6H4CꢀCAg]n (17),
and [o-IC6H4CꢀCAg]n (18)
Conclusion
In a 10-mL round bottom flask, silver nitrate (1 mmol) was
added to a solution of acetonitrile or methanol (40 mL) that
contained an equimolar amount of halosubstituted phenyl acet-
ylene and triethylamine (1 mmol). After vigorous stirring for
2 h, the yellow precipitate was collected by filtration and washed
The present work reports the structural characterization of
a series of 10 silver(I) nitrate complexes containing carbon-
rich ligands each composed of a halosubstituted phenyl
nucleus bearing a terminal ethynyl group at various positions.

Silver Complexes Bearing Nitrate and Halophenylethynide
I
thoroughly with 3 ꢄ 20 mL methanol. nmax (KBr)/cmꢃ1 (nCꢀC, w)
2050, 10; 2048, 11; 2034, 12; 2010, 13; 2010, 14; 2031, 15;
2025, 16; 2024, 17; 2018, 18.
General Procedure for Crystallization of Silver Ethynide
Complexes 1, 2, 3A, and 4–9 via Slow Liquid Diffusion
AgNO3 (0.510 g, 3 mmol) was first dissolved in DMSO (1 mL),
and polymeric [AgCꢀCR]n (,100 mg) was then added to the
solution. After stirring until all solids had dissolved, the solution
was filtered and the filtrate transferred to a test-tube. De-ionized
water was layered over the filtrate, which was stored in the dark.
Crystals of good quality were deposited after 1 week by slow
liquid diffusion of water into the filtrate.
(p-ClC6H4CꢀCAg)2ꢂAgNO3 (1)
Colourless plate-like crystals in ,75 % yield. Anal. calc. for
C16H8Ag3Cl2NO3: C 29.26, H 1.23, N 2.13; found C 29.67,
H 1.47, N 1.91. nmax (KBr)/cmꢃ1 2007 (w, nCꢀC). Compound 1
decomposes above 2208C.
(p-BrC6H4CꢀCAg)2ꢂAgNO3 (2)
Colourless plate-like crystals of in ,75 % yield. Anal. calc.
for C16H8Ag3Br2NO3: C 25.77, H 1.08, N 1.88; found C 25.41,
H 1.29, N 1.58. nmax (KBr)/cmꢃ1 2000 (w, nCꢀC). Compound 2
decomposes above 2208C.
(p-IC6H4CꢀCAg)4ꢂ(AgNO3)2 (3A)
Yellow plate-like crystals of 3A were deposited in ,60 %
yield. Anal. calc. for C32H16Ag6I4N2O6: C 22.89, H 0.96,
N 1.67; found C 22.81, H 1.07, N 1.41. nmax (KBr)/cmꢃ1 2019
(w, nCꢀC). Compound 3A decomposes above 2008C.
(p-IC6H4CꢀCAg)2ꢂAgNO3 (3B)
AgNO3 (0.510 g, 3 mmol) was dissolved in 1 mL acetonitrile.
Then [p-IC6H4CꢀCAg]n (,55 mg) was added to the solution.
After stirring for approximately half an hour, the solution was
filtered and the filtrate stored at ꢃ108C in a refrigerator. One day
later, yellow needle-like crystals of 3B were deposited in ,45 %
yield. Anal. calc. for C16H8Ag3I2NO3: C 22.89, H 0.96, N 1.67;
found C 22.80, H 1.02, N 1.48. nmax (KBr)/cmꢃ1 2013 (w, nCꢀC).
Compound 3B decomposes above 2008C.
(m-ClC6H4CꢀCAg)2ꢂAgNO3 (4)
Colourless plate-like crystals in ,75 % yield. Anal. calc. for
C16H8Ag3Cl2NO3: C 29.26, H 1.23, N 2.13; found C 28.77,
H 1.34, N 2.21. nmax (KBr)/cmꢃ1 2006 (w, nCꢀC). Compound 4
decomposes above 2008C.
(m-BrC6H4CꢀCAg)2ꢂAgNO3 (5)
Pale yellow plate-like crystals in ,75 % yield. Anal. calc. for
C16H8Ag3Br2NO3: C 25.77, H 1.08, N 1.88; found C 25.61,
H 1.18, N 1.68. nmax (KBr)/cmꢃ1 2037 (w, nCꢀC). Compound 5
decomposes above 2008C.
(m-IC6H4CꢀCAg)2ꢂAgNO3ꢂH2O (6)
Colourless needle-like crystals in ,5 % yield. Compound 6
decomposes above 2008C.
(o-ClC6H4CꢀCAg)2ꢂAgNO3 (7)
Colourless needle-like crystals of 7 in ,65 % yield. Anal.
calc. for C16H8Ag3Cl2NO3: C 29.26, H 1.23, N 2.13; found

J
P.-S. Cheng, S. C. K. Hau, and T. C. W. Mak
C 29.42, H 1.06, N 2.36. nmax (KBr)/cmꢃ1 2022 (w, nCꢀC).
Compound 7 decomposes above 1808C.
(g) H.-B. Xu, L.-Y. Zhang, X.-M. Chen, X.-L. Li, Z.-N. Chen, Cryst.
Growth Des. 2009, 9, 569. doi:10.1021/CG800866R
[3] (a) F. Paul, C. Lapinte, Coord. Chem. Rev. 1998, 178–180, 431.
doi:10.1016/S0010-8545(98)00150-7
(o-BrC6H4CꢀCAg)3ꢂAgNO3 (8)
(b) V. W.-W. Yam, K. M.-C. Wong, Top. Curr. Chem. 2005, 257, 1.
doi:10.1007/B136069
(c) S. Rigaut, C. Olivier, K. Costuas, S. Choua, O. Fadhel, J. Massue,
P. Turek, J. Y. Saillard, P. H. Dixneuf, D. Touchard, J. Am. Chem. Soc.
2006, 128, 5859. doi:10.1021/JA0603453
Colourless needle-like crystals of 8 in ,50 % yield. Anal.
calc. for C24H12Ag4Br3NO3: C 27.89, H 1.17, N 1.36; found
C 27.68, H 1.21, N 1.42. nmax (KBr)/cmꢃ1 2016 (w, nCꢀC).
Compound 8 decomposes above 1808C.
(d) G. A. Koutsantonis, G. I. Jenkins, P. A. Schauer, B. Szczepaniak,
B. W. Skelton, C. Tan, A. H. White, Organometallics 2009, 28, 2195.
doi:10.1021/OM800992P
(o-IC6H4CꢀCAg)2ꢂAgNO3ꢂDMSO (9)
Yellow needle crystals of 9 in ,50 % yield. Anal. calc. for
C18H14Ag3I2NO4S: C 23.56, H 1.54, N 1.53; found C 23.67,
H 1.47, N 1.61. nmax (KBr)/cmꢃ1 2011 (w, nCꢀC). Compound 9
melts from 162.4 to 164.18C.
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Crowley, Inorg. Chem. 2011, 50, 1123. doi:10.1021/IC1020059
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M. D. Ward, Chem. – Eur. J. 2006, 12, 9299. doi:10.1002/CHEM.
200600698
X-Ray Crystallographic Study
Selected crystals were used for intensity data collection on a
Bruker AXS Kappa Apex II Duo diffractometer at 296 K using
frames of oscillation range 0.38, with 28 , y , 288. As crystals
of complex 6 are rather brittle and easily shattered by cutting, a
fairly large one was selected for data collection, which accounts
for the abnormally low precision of the structure analysis.
A multiscan absorption correction was applied to all measured
intensity data using the SADABS program.[17] The structures
were solved by the direct method and refined by full-matrix
least-squares on F2 using the SHELXTL program package.[18]
The crystallographic data are summarized in Table 1. CCDC
1015550–1015559 contain the crystallographic data for this
paper, which can be obtained free of charge from the Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_
request/cif.
(c) D. Salazar-Mendoza, S. A. Baudron, M. W. Hosseini, Chem.
Commun. 2007, 2252. doi:10.1039/B704466F
(d) C. Ferna´ndez-Cortabitarte, F. Garc´ıa, J. V. Morey, M. McPartlin,
S. Singh, A. E. H. Wheatley, D. S. Wright, Angew. Chem. Int. Ed. 2007,
46, 5425. doi:10.1002/ANIE.200700925
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(c) N. J. Long, C. K. Williams, Angew. Chem. Int. Ed. 2003, 42, 2586.
doi:10.1002/ANIE.200200537
(d) V. W.-W. Yam, J. Organomet. Chem. 2004, 689, 1393.
doi:10.1016/J.JORGANCHEM.2003.12.029
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Supplementary Material
[6] (a) C. P. McArdle, J. J. Vittal, R. J. Puddephatt, Angew. Chem. Int. Ed.
2000, 39, 3819. doi:10.1002/1521-3773(20001103)39:21,3819::
AID-ANIE3819.3.0.CO;2-6
Descriptions of crystal structures 2 and 5 are available on the
Journal’s website.
(b) C. P. McArdle, M. C. Jennings, J. J. Vittal, R. J. Puddephatt,
Chem. – Eur. J. 2001, 7, 3572. doi:10.1002/1521-3765(20010817)
7:16,3572::AID-CHEM3572.3.0.CO;2-C
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Puddephatt, Chem. – Eur. J. 2002, 8, 723. doi:10.1002/1521-3765
(20020201)8:3,723::AID-CHEM723.3.0.CO;2-T
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Acknowledgements
We gratefully acknowledge financial support by the Hong Kong Research
Grants Council (GRF CUHK 402710), the Wei Lun Foundation, and the
award of a Postgraduate Studentship to P.-C. Cheng and a Postdoctoral
Research Fellowship to S. C. K. Hau respectively from The Chinese Uni-
versity of Hong Kong.
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