Construction of two new 3D supramolecular networks with 3-pyridyl-4-yl-benzoic acid ligands: Synthesis, characterization, and luminescence

Article abstract of DOI:10.1134/S1070328414010011

Two new coordination polymers with 3-pyridyl-4-yl-benzoic acid (3,4-HPybz), namely, [Zn(3,4-Pybz)₂·2H₂O] _n (I) and [Ag(3,4-Pybz)(3,4-HPybz)] _n (II), have been synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single crystal X-ray diffraction. Compound I crystallizes in the triclinic system and has P1 space group. Complex I is an infinite 1D chain polymer and the infinite chains array uniformly in a 3D supramolecular network which posesses abundant O-H.O hydrogen-bonding interactions among the occupied and unoccupied carboxylate O atoms and the coordinated water molecules; compound II crystallizes in the triclinic system and has Pbar 1 space group, II is an infinite chain with the repeat sequence of Ag1(I)-Ag2(I)-Ag1(I), in which weak intermolecular interactions play a key role in forming the final 3D supramolecular architectures. The photoluminescences and lifetime of I and II in the solid state have been investigated.

Full text of DOI:10.1134/S1070328414010011

ISSN 1070ꢀ3284, Russian Journal of Coordination Chemistry, 2014, Vol. 40, No. 1, pp. 10–15. © Pleiades Publishing, Ltd., 2014.
Construction of Two New 3D Supramolecular Networks
with 3ꢀPyridylꢀ4ꢀylꢀBenzoic Acid Ligands: Synthesis,
Characterization, and Luminescence1
J. Guoa, b, S. J. Lia, D.ꢀL. Miaoc, J. S. Liua, *, and W. D. Songb, *
aSchool of Environmental Science and Engineering, Donghua University, Shanghai, 200051 P.R. China
bSchool of Petrolium & Chemical Engineering, Zhejiang Ocean University, Zhoushan, 316000 P.R. China
cCollege of Food Science and Technology, Guangdong Ocean University, Zhanjiang, 524088 P.R. China
*eꢀmail: liujianshe@dhu.edu.cn; songwd60@126.com
Received April 17, 2012
Abstract
Pybz)2
mental analysis, IR spectroscopy, thermogravimetric analysis, and single crystal Xꢀray diffraction. Comꢀ
pound crystallizes in the triclinic system and has 1 space group. Complex is an infinite 1D chain polymer
and the infinite chains array uniformly in a 3D supramolecular network which posesses abundant O–H···
hydrogenꢀbonding interactions among the occupied and unoccupied carboxylate O atoms and the coordiꢀ
nated water molecules; compound II crystallizes in the triclinic system and has space group, II is an infiꢀ
—
Two new coordination polymers with 3ꢀpyridylꢀ4ꢀylꢀbenzoic acid (3,4ꢀHPybz), namely, [Zn(3,4ꢀ
⋅
2H2O]n ( ) and [Ag(3,4ꢀPybz)(3,4ꢀHPybz)]n (II), have been synthesized and characterized by eleꢀ
I
I
P
I
O
P1
nite chain with the repeat sequence of Ag1(I)–Ag2(I)–Ag1(I), in which weak intermolecular interactions
play a key role in forming the final 3D supramolecular architectures. The photoluminescences and lifetime
of and II in the solid state have been investigated.
I
DOI: 10.1134/S1070328414010011
1
INTRODUCTION
as 3ꢀpyridylꢀ3ꢀylꢀbenzoate and 4ꢀpyridylꢀ4ꢀylꢀbenꢀ
zoate, have been proved to be excellent candidates for
constructing novel coordination polymers with differꢀ
ent properties [6].
The past decade has witnessed tremendous
progress in the synthesis of metalꢀorganic frameworks
and the investigation of their properties. The comꢀ
pounds based on the ligands and metal centers display
a great variety of properties, such as molecular recogꢀ
nition, heterogeneous catalysis, ion exchange, magꢀ
netic and photochemical areas, as well as their intriguꢀ
ing variety of topologies [1–4]. Generally, the diversity
of the framework structures of such materials as the reꢀ
sult of the selfꢀassemble process greatly depends on
the selection of the metal centers and organic spacers,
as well as on the reaction pathways [5]. In addition,
weak intermolecular forces in these coordination
polymers have been wellꢀstudied and can be used to to
design and synthesize complexes with interesting arꢀ
chitectures and functions. The judicious selection of a
multifunctional ligand with hydgrogen donors and acꢀ
ceptors and suitable spacers between linking groups to
connect metal ions to generate a fascinating configuꢀ
ration is a common strategy.
However, their isomeric building block 3ꢀpyridinꢀ
4ꢀylꢀbenzoate has been largely unexplored so far
[7, 8]. Four 3D complexes assembled from Mn(II),
Zn(II), Cd(II), or Pb(II) with 3,4ꢀPybz are presented
in [9], two isostructural complexes are obtained in [10]
and three isostructural complexes are reported and
studied the magnetic properties in [11].
We choose the unsymmetrical ligand 3ꢀpyridinꢀ4ꢀ
ylꢀbenzoic acid (3,4ꢀHpybz) in the selfꢀassembly. Heꢀ
rein, we report two 3D supramolecular networks:
[Zn(3,4ꢀPybz)2
HPybz)]n (II). Complexes
chains and extended into the final 3D framework via
hydrogen bonding and/or stacking interactions.
·
2H2O]n
(I), [Ag(3,4ꢀPybz)(3,4ꢀ
I
and II are 1D infinite
π π
–
EXPERIMENTAL
Materials and measurements. All solvents and reꢀ
agents were commercially available and used without
further purification. Elemental (C, H, and N) analyses
were performed on PerkinElmer 240 CHN element
analyzer. Infrared (IR) spectra were recorded (4000–
400 cm–1) as KBr disks on a Bruker 1600 FTIR specꢀ
trometer. Thermogravimetric analysis (TGA) experiꢀ
NꢀHeterocyclic multicarboxylic acids have been
widely used to construct coordination polymers for
their potential application. Among the reported
frameworks, the multifunctional organic ligands that
incorporate both pyridyl and carboxylate groups, such
1
The article is published in the original.
10

CONSTRUCTION OF TWO NEW 3D SUPRAMOLECULAR NETWORKS
11
ments were carried out on a PerkinElmer TG/DTA gles and hydrogen bonds are listed in Table 2. Suppleꢀ
6300 system with a heating rate of 10 C/min from mentary material has been deposited with the Cambridge
room temperature to 600 C under nitrogen atmoꢀ Crystallographic Data Centre (nos. 857472 ( ),
sphere. Luminescence spectra for crystal solid 857472 II); deposit@ccdc.cam.ac.uk or http://
samples were recorded at room temperature on a Hiꢀ www.ccdc.cam. ac.uk).
tachi Fꢀ4500 fluorescence spectrophotometer.
Synthesis of complex I. A mixture of Zn(NO3)2
°
°
I
(
·
RESULTS AND DISCUSSION
6H2O (0.14 g, 0.5 mmol), 3,4ꢀHPybz (0.1 g, 0.5 mmol)
and H2O (10 mL) with pH adjusted to 4 was stirred for
30 min in air. Afterwards, it was sealed in a 20 mL Teflon
The asymmetric unit of I (Fig. 1a) consists of one
Zn2+ ion, two 3,4ꢀPybz ligands and two coordinated
water molecules. Each Zn(II) center is hexaꢀcoordinatꢀ
ed with a distorted octahedral coordination geometry
reactor and kept under autogenous pressure at 150
for 96 h. The mixture was cooled to room temperature
at a rate of 5
tained in a yield of 51% based on Zn.
°C
°
C h–1 and colorless plate crystals were obꢀ supplied by two carboxylate oxygen atoms from one
3,4ꢀPybz ligand, two nitrogen atoms from two different
3,4ꢀPybz ligands and two oxygen atoms from two coorꢀ
dinated water molecules. The Zn(1)–Ocaboxylate bonds
For C24H20N2O6Zn (
I)
(2.175(4) and 2.194(4)
Zn–Owater bonds (1.997(4) and 2.109(4)
due to that the carboxylate group in the bidentate
chelating mode weakens the Zn–O bonding interacꢀ
tions. All Zn–O distances (from 1.997(4) to 2.194(4)
and Zn–N distances (from 2.100(4) to 2.305(5)
falls in the normal range. 3,4ꢀPybz ligands in complex
display two kinds of coordination modes:
Å
) are slightly longer than the
anal. calcd., %: C, 57.85;
H, 4.02;
H, 4.06;
N, 5.62.
N, 5.63.
Å). This may
Found, %:
C, 57.78;
IR bands (KBr;
, cm–1): 3242 s, 1589 s, 1537 v.s, 1409 s,
ν
Å
)
)
1373 s, 1196 w, 1136 s, 1036 w, 1007 w, 863 s, 779 v.s,
708 w, 558 w, 484 w.
Synthesis of complex II. A mixture of AgNO3
(0.09 g, 0.5 mmol), 3,4ꢀHpybz (0.14 g, 0.5 mmol) and
water (15 mL) was stirred for 30 min in air with the pH
of 8 adjusted by NaOH, sealed in a 20 mL Teflon reacꢀ
Å
I
Zn
Zn
N
N
tor and kept under autogenous pressure at 170
72 h. The mixture was cooled to room temperature at
a rate of 5
C h–1 and colorless plate crystals were obꢀ
tained in a yield of 36% based on Ag.
°C for
°
O
O
O
O
Zn
For C24H17N2O4Ag (II
)
anal. calcd., %: C, 57.00;
H, 3.36;
H, 3.33;
N, 5.54.
N, 5.63.
Ag
Ag
N
N
Found, %:
C, 56.82;
IR bands (KBr;
, cm–1): 3067 w, 1695 s, 1592 s, 1433 s,
1340 w, 1135 s, 864 s, 812 w, 776 s, 742 w, 705 w, 507 w.
ν
Xꢀray structure determination. Diffraction data of
HO
O
O
O
complexes
SMART CCD 1000 diffractometer operating at 50 kV
and 30 mA using Mo radiation ( = 0.71073 ) at
298 K. Data collection and reduction were performed
using the SMART and SAINT software [12], Multiꢀ
I and II were performed on a Bruker
Ag
Scheme 1.
K
λ
Å
α
One moda connects one Zn(II) center via pyridylꢀN
scan absorption correction was applied using the atom; the other chelates one Zn(II) center via the carꢀ
SADABS program [12]. The structures were solved by boxylate group in the bidentate chelating mode and
direct methods and refined by fullꢀmatrix leastꢀ bridges another Zn(II) center via one pyridylꢀN atom.
squares techniques using the SHELXTL program Based on such coordination modes of L ligands, an inꢀ
package [13]. All nonꢀhydrogen atoms were treated finite 1D chain was formed (Fig. 1b), such adjacent 1D
anisotropically. The hydrogen atoms belonging to C chains are connected into a 2D layer via O(2
w)–
and N atoms were calculated theoretically. The hydroꢀ H(4 ···O(3) hydrogenꢀbonding interaction between
w)
gen atoms of water molecules were located in a differꢀ the depronated carboxylate O atoms and the coordinatꢀ
ence Fourier maps. Hydrogen atoms on water moleꢀ ed water molecules (Fig. 1c). The 2D layers are further
cules were located from difference Fourier maps and extended into 3D supramolecular net via O–H···O hyꢀ
refined with distance restraints of O–H 0.84(2)
···H 1.39(2) . Crystal data and details of the data O(1
collection and refinement for two compounds are listꢀ among the occupied and unoccupied carboxylate O atꢀ
ed in Table 1. The data for selected bond lengths, anꢀ oms and the coordinated water molecules (Fig. 1d).
Å
and drogenꢀbonding interactions (O(2
w
w
)–H(3
)–H(1
w
)
···O(4),
H
Å
w
)–H(2 ···O(3), and O(1
w
)
w)···O(2))
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 40
No. 1
2014

12
GUO et al.
Table 1. Crystallographic data and refinement parameters for structures
I
and II
Value
Parameter
I
II
Empirical formula
C24H29N2O6Zn
497.79
C24H17N2O4Ag
505.27
Formula weight
Crystal size, mm
Crystal system
Space group
0.42
×
0.39
×
0.21
0.30
×
0.28 × 0.11
Triclinic
Triclinic
P
1
P1
a
, Å
, Å
6.0528(6)
7.7930(4)
8.2484(9)
b
10.3371(11)
12.2031(14)
89.588(2)
87.0870(10)
70.9240(10)
982.03(19)
1.709
c
, Å
11.6702(12)
84.386(2)
75.8830(10)
84.801(2)
530.02(8)
1.560
α
,
deg
deg
deg
Å3
β
,
γ,
V
,
ρcalcd,
mg/cm3
Z
1
2
F(000)
256
508
Absorption coefficient, mm–1
1.204
1.062
Max and min transmission
0.7861 and 0.6317
2.63–25.00
0.8921 and 0.7411
2.62–25.00
θ
Range for data collection, deg
Limiting indices
–6
≤
h
≤
7, –9
≤
k
≤
9, –13
≤
l
≤
12 –9
≤
h
≤
9, –12
≤
k
≤
12, –14
≤
l ≤ 10
Reflections collected/unique
2714/2207
98.2
5119/3400
98.70
Completeness to θ = 25.00, %
Data/restraints/parameters
GOOF
2207/9/298
1.068
3400/0/283
1.023
Final
R
indices (
I
> 2
σ(
I
))
R
1 = 0.0282, wR2 = 0.0650
1 = 0.0294, wR2 = 0.0657
R
1 = 0.0389, wR2 = 0.0805
R
indices (all data)
R
R1 = 0.0644, wR2 = 0.0956
R1
=
Σ
(|
F
o| – |
F
c|)
/
Σ
|
Fo
|
wR2 = [
Σ
w
(|F
o|2 – |
F
c|2)2
/ w
(Fo)2]1 2
.
Σ
Table 2. Geometric parameters of hydrogen bonds for complexes I and II*
Distance, Å
H···A
Contact D–H···A
Angle D–H···A, deg
D–H
D···A
I
O(2
O(2
O(1
O(1
w
w
w
w
)–H(4
)–H(3
)–H(2
)–H(1
w)···O(3a)
w)···O(4b)
w)···O(3b)
w)···O(2c)
0.85
0.85
0.85
0.85
1.95
1.84
1.76
1.84
II
2.793(6)
2.685(6)
2.613(5)
2.674(5)
173
171
176
165
O(4)–H(4)···O(1)a
0.82
1.66
2.459(4)
164
* Symmetry codes: (a)
x,
y
+ 1,
z
– 1; (b)
x + 1, y + 1, z – 1; (c) x + 1, y, z (I); (a) x – 1, y + 1, z (II).
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 40
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2014

CONSTRUCTION OF TWO NEW 3D SUPRAMOLECULAR NETWORKS
13
(a)
(a)
ii
i
N(2
)
N(1 )
C(23)
O(2)
C(22)
C(21)
Ag(2)
N(2)
C(18)
C(15)
i
i
O(3)
C(13)
C(24)
N(2)
Zn(1)
C(17)
N(1 )
C(19)
O(3 ) Ag(1)
O(3)
C(15)
C(13)
C(16)
C(21)
C(17)
C(20)
C(16)
C(6)
C(20)
C(7)
C(14)
O(1w
)
C(14)
O(4)
O(4)
N(1)
C(24)
C(19)
C(12)
C(11)
C(8)
C(9)
C(1)
C(10)
C(9)
C(11)
C(18)
C(5)
C(22)
O(2
w
)
C(2)
O(1)
C(4)
C(23)
C(12)
C(5)
C(3)
C(3)
C(2)
C(4)
C(8)
N(1)
C(10)
O(2)
C(1)
C(6)
y
C(7)
(b)
(c)
O(1)
Zn
N
z
(b)
(c)
O
C
x
x
z
y
y
z
z
x
y
x
Ag
N
O
C
(d)
(d)
z
y
x
z
x
Fig. 1. Thermal ellipsoid plot of the asymmetry unit of
(30% probability ellipsoids). Symmetry code: – 1,
+ 1 (a); an infinite chain in (b); 2D sheet consisting of
1D chains linked by O(2 )–H(4 ···O(3) hydrogenꢀ
bonding interactions (c); 3D supramolecular structure
formed by O(2 )–H(3 ···O(4), O(1 )–H(2 ···O(3),
and O(1 )–H(1 ···O(2) (d). In (c) and (d), the hydrogen
atoms not involved in forming hydrogen bonds are omitted
for clarity.
I
y,
I
=
x
z
I
w
Fig. 2. The coordination environment of Ag(1) and Ag(2)
w)
i
in II (30% probability ellipsoids). Symmetry code:
⎯y + 2, –z + 1; –x, –y, –z + 2 (a); an infinite chain with
–x,
ii
w
w)
w)
w
w)
Ag1(I) and Ag2(I) centers arranged alternatively in II (b);
a wavelike layer constructed via O–H···O hydrogen bondꢀ
ing interactions (c) (hydrogen atoms not involved in formꢀ
ing hydrogen bonds are omitted for clarity); 3D supramoꢀ
lecular structure formed by hydrogen bonding interactions
w
and
π
··· stacking interactions (d).
π
Compound II has a 1D chain structure. As shown
in Fig. 2a, there exist two types of coordination enviꢀ
ronments around the Ag ions in the crystal structure.
Ag(1) ion is ligated with two nitrogen atoms (Ag(1)–N
(Ag(1)–O 2.634(3) Å) from four different 3,4ꢀPybz
ligands, forming a distorted square planar coordinaꢀ
2.243(3)
Å) and two carboxylate oxygen atoms tion geometry. While each Ag(2) ion is coordinated by
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 40
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2014

14
Mass, %
GUO et al.
100
80
60
40
20
0
b
a
b
a
300 320 340 360 380 400 420 440 460 480
Wavelenght, nm
100
200
300
400
500 600
Temperature, °C
Fig. 4. Solidꢀstate emission spectra of
room temperature.
I (a) and II (b) at
Fig. 3. The TGA curves of complexes I (a) and II (b).
from 209 to 394
ity as no strictly clean weight loss step occurs below
°
C. Complex II shows thermal stabilꢀ
two nitrogen atoms (Ag(2)–N 2.181(4) Å) from two
3,4ꢀPybz ligands to furnish a linear coordination geꢀ
ometry. 3,4ꢀPybz ligands in complex II display two
kinds of coordination modes (Scheme 1): one acts as
terminal ligand to coordinate one Ag(I) center in
monodentate; the other bridges two Ag(I) centers via
one carboxylate O atom and one pyridylꢀN atom.
Thus, an infinite chain with Ag(1) and Ag(2) centers
arranged alternatively was generated, in which the adꢀ
253
253
°
°
C. The weightꢀloss step occurs above 291 and
C which corresponds to the decomposition of
frameworks and the residue accounts for 21.9%, which
is nearly in agreement with the calculated value of
18.9%, by assuming the final product is Ag.
Due to the fact that coordination polymers are able
to adjust the emission wavelength of organic ligands
via incorporation of metal atoms, it is quite of imporꢀ
tance to investigate the luminescence properties of coꢀ
ordination polymers in view of potential applications
as lightꢀemitting diodes [14]. The photoluminescence
jacent Ag···Ag distance is 11.966(4)
are abundant weak interactions around Ag(1) and
Ag(2). Ag(1)···O(1), Ag(2)···O(2), and Ag(2)···O(4)
(2.913(4), 3.045(3), and 2.833(4) , respectively),
which are shorter than the sums of the van der Waals
radii of Ag and O (3.24 ). The adjacent chains are
connected into an wavelike layer via O–H···O hydroꢀ
gen bonding interactions (Fig. 2c), which combine
with ··· stacking interactions (the shortest centroid–
centroid distance between parallel benzene and pyꢀ
ridyl rings of the 3,4ꢀPybz ligands is 3.36(9) and the
shortest centroid–centroid distance between parallel
pyridyl rings is 3.841(3) ) contribute to the formation
Å (Fig. 2b). There
Å
of
temperature. As indicated in Fig. 4, the emission specꢀ
tra of complexes and II exhibit strong emission. The
emission maxima (λem) are 406 nm ( ) and 362 nm (II
λex = 330 nm for , 270 nm for II), respectively. Comꢀ
pared with the case of the free ligand 3,4ꢀHPybz with
maximum emission peak at 387 nm (λex = 327 nm) reꢀ
ported previously [9], the maximal emission of may
I and II were investigated in the solid state at room
Å
I
I
)
π
π
(
I
Å
I
Å
be attributed to the ligandꢀcentered transitions [9].
The blue shift of the luminescence of II compared to
that of the free ligand may originate from the coordiꢀ
nation effect of the ligand to the silver ions [15].
of a 3D supramolecular network (Fig. 2d).
The absorption band at 3242 cm–1 for
the presence of the water molecules, while the characꢀ
I
indicates
teristic peaks at 1589, 1537 and 1409, 1373 cm–1 for
I,
1592 and 1433, 1340 cm–1 for II, are associated with
the asymmetric (COO) and symmetric (COO)
ACKNOWLEDGMENTS
stretching vibrations. The peak at 1695 cm–1 for
characteristic of free carboxyl groups.
I is
The work was supported by the National Marine
Public Welfare Projects (grant no. 2000905021), the
Guangdong Oceanic Fisheries Technology Promotion
Project (grant no. A2009003–018(c)), the Guangdong
TGA of compounds
N2 atmosphere when the samples were heated to
600 C at a constant rate of 10
are depicted in Fig. 3. For complex
loss of 7.16% from 63 to 201 C is attributed to the deꢀ Guangdong Province key project in the field of social
I and II were performed in a
°
°
C/min. The TG curves Chinese Academy of Science comprehensive strategic
I
, the initial mass cooperation project (grant no. 2009B091300121), the
°
parture of two water molecules (calcd. 7.23%), whereꢀ development (grant no. A2009011–007(c)), the Sciꢀ
as the release of 3,4ꢀPybz ligand molecules occurred ence and Technology Department of Guangdong
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 40
No. 1
2014

CONSTRUCTION OF TWO NEW 3D SUPRAMOLECULAR NETWORKS
15
7. Zhang, Y.B., Zhou, H.L., He, C.T., et al., Chem.
J. Chin. Univ., 2011, vol. 324, p. 97.
Province Project (grant no. 00087061110314018) and
the Guangdong Natural Science Fundation
(no. 9252408801000002).
8. Fang, W.H., Wang, Z.L., and Yang, G.Y., Chin. J. Inorg.
Chem., 2010, vol. 26, p. 1917.
9. Jiang, X.J., Du, M., Sun, Y., et al., J. Solid. State
Chem., 2009, vol. 182, p. 3211.
10. Guo, F., Z. Anorg. Allg. Chem., 2010, vol. 636, p. 857.
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