Syntheses, structures and fluorescent properties of two silver(I) complexes with 5-sulfo-salicylic acid as ligand templated by alkaline-earth metals

Article abstract of DOI:10.1016/j.inoche.2006.04.021

Two silver(I) complexes, [Mg(H₂O)₆][Ag₂(HL)₂] (1) and Sr₂Ag₄(HL)(H₂O)₁₄ · 2H₂O (2) (H₃L = 5-sulfo-salicylic acid), have been synthesized by use of alkaline-earth metals (Mg²⁺ and Sr²⁺, respectively) as templates. Single-crystal X-ray diffractions reveal that compound 1 is a 1-D chain polymer built from [Ag₂(HL)₂] dimers and compound 2 is a 2-D framework constructed from unusual tetramer units of [Ag₂(HL)₂] dimers. The two complexes are both further linked into 3-D networks by the extensive intermolecular hydrogen bonding interactions.

Full text of DOI:10.1016/j.inoche.2006.04.021

Inorganic Chemistry Communications 9 (2006) 767–771
www.elsevier.com/locate/inoche
Syntheses, structures and fluorescent properties of two
silver(I) complexes with 5-sulfo-salicylic acid as ligand templated
by alkaline-earth metals
*
Qiang Li, Ming-Lai Fu, Xi Liu, Guo-Cong Guo , Jin-Shun Huang
State Key Laboratory of Structure Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences,
Fuzhou, Fujian 350002, PR China
Received 16 February 2006; accepted 14 April 2006
Available online 4 May 2006
Abstract
Two silver(I) complexes, [Mg(H2O)6][Ag2(HL)2] (1) and Sr2Ag4(HL)(H2O)14 Æ 2H2O (2) (H3L = 5-sulfo-salicylic acid), have been
synthesized by use of alkaline-earth metals (Mg2+ and Sr2+, respectively) as templates. Single-crystal X-ray diffractions reveal that com-
pound 1 is a 1-D chain polymer built from [Ag2(HL)2] dimers and compound 2 is a 2-D framework constructed from unusual tetramer
units of [Ag2(HL)2] dimers. The two complexes are both further linked into 3-D networks by the extensive intermolecular hydrogen
bonding interactions.
Ó 2006 Elsevier B.V. All rights reserved.
Keywords: Alkaline-earth metals; Silver complexes; Template synthesis; Tetramer
In recent years, much efforts have been made for con-
trolling the assembly of molecules and designing the crystal
structures of coordination polymers [1] for their potential
applications as functional materials on catalysis, nonlinear
optics, microelectronics, sensors, and molecular recogni-
tion [2]. Numerous studies on this challenge have reveled
that many factors affect the assembly of molecules, and lit-
tle change of the synthetic conditions can often result in the
different ultimate structure. Recently self-assembly synthe-
ses with alkali or alkaline earth metals as template are of
great interest due to their abilities in the controlling of mol-
ecules assembly and the crystal structures of coordination
polymers [3]. There is a need for much work to be done
in understanding the nature of the reactions, which plays
a crucial role in the design of novel functional materials.
On the other hand, the selection of suitable ligand is
important in the design of novel coordination polymers
[4]. 5-Sulfosalicylic acid (H3L), which contains –OH,
–COOH, and –SO3H groups, can offer versatile coordina-
tion modes, and was selected as ligand in the present work
due to its potential multi-coordinating ability. Although
the ligand has been known for a long time and some
metal complexes bridged with it have been reported so
far [5,6], the silver coordination polymers based on H3L
ligand have been reported to be very limited [6]. When
synthesizing these Ag+ complexes, the different synthetic
conditions always result in very different structure motif
[6]. Great efforts have been made on the pH value of
the solutions have great effects on the resulting complexes.
In this contribution, after AgNO3 and H3Ssal were dis-
solved in water, the pH value of the solution was adjusted
with [N(CH2CH3)4](OH) to about 5. Then different alkali
earth ions (Mg2+ and Sr2+) are introduced as templates
into the reactions, respectively [7], and result in two silver
coordination polymers, [Mg(H2O)6][Ag2(HL)2] (1) with 1-D
chain polymer built from the [Ag2(HL)2] building block,
and [Sr2Ag4(HL)(H2O)14] Æ 2H2O (2) with 2-D framework
constructed from unusual tetramer units of [Ag2(HL)2]
building block [8].
*
Corresponding author. Fax: +86 591 837 14946.
E-mail address: gcguo@ms.fjirsm.ac.cn (G.-C. Guo).
1387-7003/$ - see front matter Ó 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.inoche.2006.04.021

768
Q. Li et al. / Inorganic Chemistry Communications 9 (2006) 767–771
Single-crystal X-ray analysis reveals that complex 1 is a
nate oxygen atoms; (f) between phenolic oxygen and
carboxylate oxygen atoms; (g) among the lattice water mol-
ecules. The chains, hydrated Mg2+ ions and the lattice
water molecules are linked to each other by these hydrogen
bonding interactions to form a 3-D supramolecular struc-
ture (Fig. S1).
1-D chain polymer with hydrated Mg2+ as counter ions
and lattice water stacking besides the chains, as shown in
Fig. 1. The asymmetric unit of 1 contains one Ag+ ion, half
occupied Mg2+ ion, one HL2ꢀ ligand, four coordinated
water molecules and two lattice water molecules. Four-
coordinated Ag1 was coordinated by two carboxylic O
atoms, one sulfonate O atom and one coordinated water
molecule with the Ag–O bond distances being in the range
Single-crystal X-ray analysis reveals that complex 2 is
2-D network constructed from the unusual tetramers of
[Ag2(HL)2] building block connected by Sr2+ ions. Four
Ag+ ions, two Sr2+, four HL2ꢀ ligand, fourteen coordi-
nated water and two lattice water molecules are found
in the asymmetric unit, as shown in Fig. S2. The coordi-
nation polyhedra of the crystallographically independent
Ag1, Ag2 and Ag4 atoms can be described as distorted
trigonal geometries, which were completed by the O12,
O32 and O12W atoms for Ag1; the O13, O33 and
O13W atoms for Ag2; and O23, O43 and O14 atoms
for Ag4. While the Ag3 atom adopts four-coordinated
mode and displays a distorted tetrahedron geometry
completed by the O42, O46, O22 and O14W atoms.
The Sr1 and Sr2 atoms are both eight-coordinated with
one phenolic oxygen atom, two sulfonate oxygen atoms
from two different HL2ꢀ ligand and five-coordinated
water molecules for Sr1 and one sulfonate oxygen atom,
one phenolic oxygen atom and six coordinated water
molecules for Sr2. The four asymmetric HL2ꢀ
ligands exhibit three types of coordination modes:
l3-j1O(2):j1O(3):j1O(4); l4-j1O(1):j1O(2):j1O(3):j1O(4);
˚
of 2.225(2)–2.591(2) A. Mg1 cation adopts six-coordinated
mode and displays octahedral coordination geometry com-
pleted by six water molecules. The HL2ꢀ ligand adopts a l3
coordination mode with sulfonate group coordinating to
one metal and carboxylate group connecting two metals
in a trans–trans mode. Two carboxylate groups of HL2ꢀ
double-bridge two symmetry-related Ag1 atoms to form
a [Ag2(HL)2] building block with the Ag atoms and carbox-
ylate groups being coplanar, which is further linked by the
O14 atoms of sulfonate groups from adjacent dimers with
the Ag1–O14 bonds approximately perpendicular to the
plane of dimer to form a chain extending along the b-axis.
The existence of abundant coordinated water, lattice
water, the ionized sulfonate group and carboxylate group
in 1 yield seven kinds of hydrogen bonding interactions
(Table S1): (a) between coordinated water molecules and
sulfonate oxygen atoms; (b) between coordinated water
molecules and phenolic oxygen atoms; (c) between coordi-
nated water molecules and lattice water molecules; (d)
between coordinated water molecules and carboxylate oxy-
gen atoms; (e) between lattice water molecules and sulfo-
l5-j1O(1):j1O(2):j1O(3):j1O(4)j1O(5),
which
are
reported for the first time (Fig. S3).
O1W
Mg1
O3W
O14
O2W
O15
S11
O16
O4W
C13
C16
C14
C15
O12
C12
Ag1
C17
C11
O13
O11
Fig. 1. ORTEP drawing of 1-D chain structure of 1 extent along the b-axis with 30% thermal ellipsoids. The lattice water molecules and hydrogen atoms
˚
are omitted for clarity. Selected bond lengths (A) and bond angles (°): Ag(1)–O(13)B 2.2245(19); Ag(1)–O(12)A 2.2292(18); Ag(1)–O(16) 2.578(2); Ag(1)–
O(4W) 2.591(2); Ag(1)–Ag(1)C 2.9143(12); Mg(1)–O(1W) 2.0780(19); Mg(1)–O(2W) 2.0393(18); Mg(1)–O(3W) 2.073(2); O(13)B–Ag(1)–O(12)A 161.81(7);
O(13)B–Ag(1)–O(16) 95.15(7); O(12)A–Ag(1)–O(16) 91.72(6); O(13)B–Ag(1)–O(4W) 87.91(7); O(12)A–Ag(1)–O(4W) 110.03(7). Symmetry code: A x,
y + 1, z; B ꢀx + 1, ꢀy, ꢀz + 1; C ꢀx + 1, ꢀy + 1, ꢀz + 1.

Q. Li et al. / Inorganic Chemistry Communications 9 (2006) 767–771
769
Each of the Ag1 and Ag2 pair, and Ag3 and Ag4 pair is
double-bridged by two HL2ꢀ ligands in a trans–trans mode
to form two kinds of [Ag2(HL)2] dimers, which link to each
other through the Ag4–O14 bond to form bi-dimer. The bi-
dimer further connects to its centrosymmetry-related unit
by Ag3–O46 bond to yield a novel tetramer of [Ag2(HL)2]
dimers (Fig. 2). Although the ½Ag2L02ꢁ (L0 = carboxylic
ligand) dimers have been found to be either isolated [9]
or linked to each other to form bi-dimer [10], 1-D [11], 2-
D [12] and 3-D [13] structures, to our best knowledge, prior
to the present work no tetramer of ½Ag2L02ꢁ dimers has been
reported. The adjacent tetramer units in 2 link to each
other by the bonding interactions of Sr1–O34, Sr1–O41,
Sr2–O31 and Sr2–O44 to form a chain extending along
the [110] direction, which are further connected to each
other by Sr1–O26 bonds to form 2-D network along the
[1ꢀ10] direction (Fig. 3). Abundant hydrogen bonds are
also found in 2, which link the layers to form 3-D supramo-
lecular structure (Table S2).
It is interesting that the two complexes were synthesized
in the similar conditions with different alkaline earth ions
added to the synthetic system, while compound 1 is a
O13W
Ag2
O14
O43
O13
O12
Ag4
O33
O32
O23
O42
Ag3
Ag1
O14W
O46A
O22
O12W
Fig. 2. The diagram of unusual tetramer of [Ag2(HL)2] dimers with hydrogen atoms being omitted for clarity. Ag(1)–O(12) 2.218(4); Ag(1)–O(32)
2.226(4); Ag(1)–O(12W) 2.489(4); Ag(1)–Ag(2) 2.8403(8); Ag(2)–O(13) 2.179(4); Ag(2)–O(33) 2.196(4); Ag(2)–O(13W) 2.497(4); Ag(3)–O(22) 2.246(4);
Ag(3)–O(42) 2.260(4); Ag(3)–O(14W) 2.426(4); Ag(3)–O(46)A 2.589(4); Ag(3)–Ag(4) 2.8499(7); Ag(4)–O(23) 2.171(4); Ag(4)–O(43) 2.188(4); Ag(4)–O(14)
2.563(4). Symmetry code: A ꢀx ꢀ 1, ꢀy, ꢀz + 1.
Fig. 3. The 2-D layer of 2 constructed from the unusual tetramer of [Ag2(HL)2] dimers connected by Sr2+ ions with the lattice water molecules and
coordinating water molecules of Sr2+ being omitted for clarity.

770
Q. Li et al. / Inorganic Chemistry Communications 9 (2006) 767–771
Young Scientist of China (20425104), and the NSF of Fuj-
ian Province (E0513019).
[Ag2(HL)2]·Mg(H2O)6
Ag4Sr2(HL)(H2O)14·2H2O
H3L
Appendix A. Supplementary data
Supplementary data associated with this article can be
found, in the online version, at doi:10.1016/j.inoche.
2006.04.021.
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s, 1485 s, 1435 s, 1353 m, 1298 s, 1265 m, 1177 m, 1121 m, 1083 m,
1038 m, 893 m, 809 m, 733 m, 672 m, 579 m, 439 m. For 2: The
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3406 s, 1595 m, 1557 s, 1485 s, 1435 s, 1353 m, 1298 s, 1265 m, 1177 m,
1121 m, 1083 m, 1038 m, 893 m, 809 m, 733 m, 672 m, 579 m, 439 m.
Acknowledgements
We gratefully acknowledge the financial support of the
NSF of China (20571075), the NSF for Distinguished

Q. Li et al. / Inorganic Chemistry Communications 9 (2006) 767–771
771
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˚
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˚
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˚
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,
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˚
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