M. Hu et al. / Inorganic Chemistry Communications 13 (2010) 1548–1551
1549
contains Ag2 centers and L ligands. In fragment B, the hydrolyzed
carboxylate group in L acts as a bridge, by linking three Ag2 atoms through
1
2
3
its two carboxylate O atoms with μ –η :η -bridging mode, generate
an almost planar four-membered ring composed of Ag2–O1B–Ag2K–O1H
and a non-planar eight-membered ring composed of Ag2–O1B–C1B–
O2B–Ag2F–O1G–C1G–O2G with the non-bonding Ag2⋯Ag2K separation
of 3.8456 Å (B=x, −y+1/2, z−1/2; F=−x+1, −y, −z; G=−x+1,
y−1/2, −z+1/2; H=−x+1, y+1/2, −z+1/2; K −x+1, −y+1,
−
z). As a consequence, such binding linkages lead to the formation of a
-D chain motif along the [010] direction (see Fig. S2 in the Supplementary
1
material, top). In addition, adjacent 1-D chains are assembled into a 2-D
layered network running parallel to the (100) plane via the Ag–S bond
between the Ag2 and S1 (see Fig. S2 in the Supplementary material,
bottom). Furthermore, two 2-D layered motifs (fragments A and B)
are alternately interlinked via the bridging L ligands, which finally produce
a 3-D coordination framework (see Fig. 3). The presence of Ag–S
interactions plays an important role in the formation of the 3-D structure.
I
Fig. 1. View of the local coordination environments of Ag atoms in 1 (purple and pink
1 2
The S atoms adopted μ -monodentate and μ -bidentate bridging
spheres correspond to Ag1 and Ag2 centers with different coordination geometries,
respectively). The atoms labeled with the suffixes A, B, C, D, E, F, G, and H are generated by
the symmetry operations (−x+2, −y, −z), (x, −y+1/2, z−1/2), (−x+2, y−1/2,
z+1/2), (−x+2, −y, −z), (x, −y−1/2, z−1/2), (−x+1, −y, −z), (−x + 1, y−1/2,
z+1/2), and (−x+1, y+1/2, −z+1/2).
I
coordination modes upon the Ag atoms. All the Ag–S bond distances
[2.5074(11)–2.6742(12) Å] are in the normal range [11,12].
−
−
Analysis of network topology provides a convenient tool in designing
and understanding the complicated crystal structures such as coordina-
tion polymers or hydrogen-bonded networks [13]. Such structures can
usually be reduced to simple topological networks with different
connectivity of the components. To further demonstrate the 3-D
structure of 1, we can consider both (Ag1) and (Ag2) dimeric units
2 2
are connected to six equivalent L ligands and could be regarded as 6-
connected nodes in the construction of this complicated network,
uses all of its four O atoms and two S atoms to coordinate to eight AgI
ions (four Ag1 and four Ag2 atoms), with two different carboxylate
1
2
coordination modes: namely μ
for O3–C6–O4 carboxylate group and μ
O1–C1–O2 carboxylate group, as well as two different S atoms
coordination modes: μ -monodentate coordination modes for S1
atom and μ -bidentate bridging modes for S2 atom (see Fig. 2). In the
2
–η :η -chelating/bridging mode
1
2
3
–η :η -bridging mode for
respectively. As such, each L ligand coordinates to three (Ag1)
2
units
1
and three (Ag2) units, so it can be reduced to a 6-connecting node. The
2
2
resulting highly unusual 6-connected network is shown in Fig. 4. It has
3
9 6
network of 1, short Ag–Ag bonding contact (3.2523 Å), so-called
argentophilic interactions, has been observed between Ag2 and Ag2F
bridged by the carboxylate groups of L (F=−x+1, −y, −z), which is
shorter than the sum of the van der Waals radii of two silver atoms
the Schläfli symbol of (412.6 )
2 2 2
(4 .6 ) (representing (Ag1) / (Ag2) / L
nodes).
I
In general, Ag complexes usually emit weak photoluminescence at
low temperature, and only a few Ag complexes exhibiting luminescent
I
(
3.44 Å) [8a,10,11].
To further confirm and better understand the connectivity between
properties at room temperature have been reported [14]. Interestingly, as
depicted in Fig. 5, complex 1 exhibits the blue fluorescent emission band
at λmax =428 nm upon excitation of 351 nm. It should be pointed out
that the free L ligand displays very weak luminescence in the solid state at
ambient temperature. According to the literature [2a,15], we can
presume that the enhancement of luminescence in 1 may be mainly
derived from Ag–Ag interactions and the nature of its emitting states
strongly depends on the number of metal centers and the interactions
between them. Although a great number of silver(I) carboxylate
complexes have been structurally characterized in recent years [16,17],
the components in the overall 3-D structure of 1, it is better to separate 1
into two types of 2-D fragments, denoted as A and B, running parallel to
thesameplane(seeFigs. S1–S2 in the Supplementary material). Fragment
A contains Ag1 centers and L ligands. Ag1 atoms are bridged by the
1
2
2
carboxylate groups with μ –η :η -chelating/bridging mode to form a
planar four-membered ring composed of Ag1–O4B–Ag1A–O4C, with the
non-bonding Ag1⋯Ag1A separations of 3.3848 Å (A=−x+2, −y, −z;
B=x, −y+1/2, z−1/2; C=−x+2, y−1/2, −z+1/2; see Fig. S1 in the
Supplementary material). Such [Ag
atoms via μ -bidentate bridging modes and leads to the formation of a 2-D
motif running parallel to the (100) plane. On the other hand, fragment B
2 2
O ] dimeric units are linked by S2
2
1
2
Fig. 2. View of coordination modes of L in 1: μ
2
–η :η -chelating/bridging mode for O3–C6–O4
–η :η -bridging mode for O1–C1–O2 carboxylate group, --
monodentate coordination mode for S1 atom, and μ -bidentate bridging mode for S2 atom.
1
2
carboxylate group,
μ
3
μ
1
2
The symmetry-related atoms labeled with the suffixes C, G, H, I, and J are generated by
the symmetry operations (−x+2, y−1/2, −z+1/2), (−x+1, y−1/2, −z+1/2), (−x+1,
y+1/2, −z+1/2), (x, −y+1/2, z+1/2), and (−x+2, y+1/2, −z+1/2).
Fig. 3. The 3-D network structure of 1 viewed along the [010] direction.
Hu, Min
