Self-assembly of two 2D copper(II) coordination networks with tetrachloro-1,3-benzenedicarboxylate: Solvent effects, supramolecular interactions, and luminescence behavior

Article abstract of DOI:10.1002/zaac.201400049

Reaction of the rigid ligand 2,4,5,6-tetrachloro-1,3-benzenedicarboxylic acid (1,3-H₂BDC-Cl₄) with copper(II) nitrate in different solvent systems afforded two new complexes {[Cu(1,3-BDC-Cl₄)(DMF)] (H₂O)}_n (1) and {[Cu(1,3-BDC-Cl₄)(H ₂O)₃] (dioxane)·(H₂O)}_n (2), which were fully characterized by elemental analysis, IR spectroscopy, as well as single crystal and powder X-ray diffiraction techniques. Single-crystal X-ray diffraction reveals that complexes 1 and 2 crystallize in different space groups P2₁/m and Pbca, respectivly. Compound 1 shows a two-dimensional (2D) (4,6)-connected layered network constructed by the connectivity between one-dimensional (1D) [-Cu-DMF-COO-]_n chains and tetrachlorinated backbones of 1,3-BDC-Cl₄, which is further assembled to generate a three-dimensional (3D) supramolecular framework through intermolecular O-H...O and O-H...Cl hydrogen-bonding interactions. Compound 2 features a 2D 4-connected sql coordination net formed by 1D [Cu-H₂O]_n chains and 1,3-BDC-Cl₄ spacers, which is further extended into a 3D supramolecular network by multiple O-H...O hydrogen-bonding interactions. The different structural features of the two compounds suggest that the choice of solvent systems should play a key role in the process of assembly. Their thermal and fluorescence properties were also investigated. Copyright

Full text of DOI:10.1002/zaac.201400049

ARTICLE
DOI: 10.1002/zaac.201400049
Self-assembly of Two 2D Copper(II) Coordination Networks with
Tetrachloro-1,3-benzenedicarboxylate: Solvent Effects, Supramolecular
Interactions, and Luminescence Behavior
Sheng-Chun Chen,*[a,b] Xin-Xin Wang,[a] Hai-Kun Luo,[a] Ming-Yang He,[a]
Cheng-Peng Li,*[c] and Qun Chen*[a,b]
Keywords: Coordination polymer; Tetrachloroisophthalate; Solvent effects; Supramolecular interactions; Luminescence
properties
Abstract. Reaction of the rigid ligand 2,4,5,6-tetrachloro-1,3-benzene-
dicarboxylic acid (1,3-H2BDC-Cl4) with copper(II) nitrate in different
backbones of 1,3-BDC-Cl4, which is further assembled to generate a
three-dimensional (3D) supramolecular framework through intermo-
solvent systems afforded two new complexes {[Cu(1,3- lecular O–H···O and O–H···Cl hydrogen-bonding interactions. Com-
BDC-Cl4)(DMF)] (H2O)}n (1) and {[Cu(1,3-BDC-Cl4)(H2O)3] pound 2 features a 2D 4-connected sql coordination net formed by 1D
(dioxane)·(H2O)}n (2), which were fully characterized by elemental [Cu-H2O]n chains and 1,3-BDC-Cl4 spacers, which is further extended
analysis, IR spectroscopy, as well as single crystal and powder X- into a 3D supramolecular network by multiple O–H···O hydrogen-
ray diffiraction techniques. Single-crystal X-ray diffraction reveals that bonding interactions. The different structural features of the two com-
complexes 1 and 2 crystallize in different space groups P21/m and pounds suggest that the choice of solvent systems should play a key
Pbca, respectivly. Compound 1 shows a two-dimensional (2D) (4,6)- role in the process of assembly. Their thermal and fluorescence proper-
connected layered network constructed by the connectivity between
one-dimensional (1D) [–Cu–DMF–COO–]n chains and tetrachlorinated
ties were also investigated.
the crystal packing via multiple non-covalent interactions.[10]
Recently, the utilization of halogen-substituted compounds has
proved to be a feasible approach for constructing diverse coor-
dination networks, since the effect of halogen groups can sig-
nificantly affect their solid structures, physical and chemical
properties by virtue of electronegativity, polarizability, and
steric requirement.[11–14] It has also been found that halogen
bonding such as C–H···X–C and X···X contacts (X = halogen),
as an important of noncovalent interactions, can be used to
modulate the supramolecular architectures or generate smart
properties in the solid state.[15–17]
Recently, we have been interested in exploring multifunc-
tional metal-organic hybrid materials based on the perhalogen-
substituted benzenedicarboxylate ligands as the functional and
structural units.[18–24] In our previous work, in virtue of sol-
vent-tuning strategy, 2,3,5,6-tetrachloro-1,4-benzenedicarbox-
ylic acid (1,4-H2BDC-Cl4) has been successfully used to con-
struct a series of polymeric MnII [18] and CuII [20] coordination
architectures with desired structural transformations and inter-
esting physical properties. As a continuation of this project, in
this contribution, we selected 2,4,5,6-tetrachloro-1,3-benzene-
dicarboxylic acid (1,3-H2BDC-Cl4) as the building block, and
two new 2D CuII CPs {[Cu(1,3-BDC-Cl4)(DMF)] (H2O)}n (1)
and {[Cu(1,3-BDC-Cl4)(H2O)3] (dioxane)·(H2O)}n (2), were
obtained by the reaction of CuII nitrate with 1,3-H2BDC-Cl4
under different mixed solvent systems (MeOH-DMF for 1, and
dioxane-H2O for 2) (see Scheme 1). To the best of our knowl-
Introduction
Design and synthesis of coordination polymers (CPs) based
on transition metal ions and organic bridging ligands has been
intensely studied due to their wide structural diversity and their
potential applications as functional materials in many
fields.[1–3] With respect to traditional organic polymers, CPs
have several advantages in terms of structural and functional
features.[4] CPs deal with metal-ligand bonds as the primary
design feature involving metal ions and bridging organic link-
ers. In this regard, the suitable selection of organic ligands and
metal ions plays a dominating role on the construction of
CPs.[5–9] Moreover, if the bridging ligand is designed with
electron-donating or electron-withdrawing groups, then it be-
comes a perfect potential supramolecular synthon to determine
* Dr. S.-C. Chen
Fax: +86-519-86330251
E-Mail: cscczu@yahoo.com
* Prof. Dr. Q. Chen
E-Mail: chenqunjpu@yahoo.com
* Dr. C.-P. Li
E–Mail: tjnulicp@gmail.com
[a] Jiangsu Key Laboratory of Advanced Catalytic Materials and Tech-
nology
Changzhou University
Changzhou 213164, P. R. China
[b] School of Chemical Engineering
Nanjing University of Science & Technology
Nanjing 210094, P. R. China
[c] College of Chemistry
Tianjin Normal University
Tianjin 300387, P. R. China
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2D Copper(II) Coordination Networks with Tetrachloro-1,3-benzenedicarboxylate
squares on F2 with SHELXL.[28] C-bound hydrogen atoms were placed
edge, this work represents the first example of complexes con-
structed from 1,3-H2BDC-Cl4. Furthermore, solid-state proper-
ties of thermal stability and luminescence for both crystalline
materials were also briefly investigated.
in geometrically calculated positions by using a riding model. O-bound
hydrogen atoms were firstly localized by difference Fourier maps and
fixed geometrically with isotropic temperature factors. Crystal data and
structural refinement parameters are summarized in Table 1, and the
selected bond lengths and angles are listed in Table 2.
Table 1. Crystal and structure refinement data for complexes 1 and 2.
1
2
Empirical formula
Formula weight
Crystal size /mm3
Crystal system
Space group
a /Å
b /Å
c /Å
α /°
β /°
CuC11H9Cl4NO6
456.54
0.24ϫ0.22ϫ0.22
monoclinic
P21/m
8.817(1)
7.264(1)
12.252(2)
90
95.633 (4)
90
780.9(2)
2
1.942
2.11
454
CuC12H16Cl4O10
525.60
0.26ϫ0.26ϫ0.20
orthorhombic
Pbca
8.499(2)
16.888(5)
27.326(8)
90
90
90
3922.1(2)
8
1.780
Scheme 1.
Experimental Section
γ /°
Reagents and Instruments: All reagents and solvents for synthesis
and analysis were commercially available and used as received. The
Fourier transform (FT) IR spectra (KBr pellet) were taken with a Nico-
let ESP 460 FT-IR spectrometer in the range of 4000–400 cm–1. Ele-
mental analyses were performed with a PE-2400II (Perkin-Elmer) ana-
lyzer. Powder X-ray diffraction (PXRD) patterns were recorded with
a Rigaku D/ max-2500 diffractometer at 40 kV and 100 mA for a Cu-
target tube (λ = 1.5406 Å). The calculated PXRD patterns were ob-
tained from the single-crystal diffraction data using the PLATON soft-
ware.[25] Thermogravimetric analysis (TGA) experiments were carried
out in the temperature range of 25–800 °C with a Dupont thermal ana-
lyzer in a nitrogen atmosphere at a heating rate of 10 °C·min–1. The
luminescence emission spectra for the powdered solid samples were
measured with a Varian Cary Eclipse spectrometer at room tempera-
ture.
V /Å3
Z
ρcalcd. /g·cm–3
μ /cm–1
1.71
2120
F(000)
Range of h, k, l
–10/10, –8/8, –13/14 –10/10, –21/21,
–26/35
Total/independent reec-
tions
4346/1489
24454/4554
Rint
R
0.052
0.0333, 0.0976
1.023
0.127
0.0617, 0.1197
0.979
b)
a), Rw
c)
GOF
Residuals /e·Å–3
0.62, –0.50
0.62, –0.99
2
2 2
2 2 1/2
a) R = ∑||Fo|–|Fc||/∑|Fo|. b) Rw = [∑[w(Fo –Fc ) ]/∑w(Fo ) ]
.
c) GOF = {∑[w(Fo –Fc ) ]/(n–p)}1/2
.
2
2 2
Table 2. Selected bond lengths /Å and angles /° for complexes 1 and
2.
{[Cu(1,3-BDC-Cl4)(DMF)] (H2O)}n (1). A mixture of 1,3-H2BDC-
Cl4 (30.4 mg, 0.1 mmol) and Cu(NO3)·3H2O (24.1 mg, 0.1 mmol) was
dissolved in the MeOH/DMF mixed solvents (v/ v, 1:1, 6 mL) with
stirring for 30 min. The resulting solution was filtered and left to stand
at room temperature. Blue block crystals of 1 suitable for X-ray dif-
fraction were obtained in ca. 7 d upon solvent evaporation in ca. 60%
yield (27.4 mg, based on 1,3-H2BDC-Cl4). C11H9Cl4CuNO6: calcd. C
28.99; N 3.07; H 1.99%; found: C 28.26; N 3.13; H 2.01%. IR (KBr):
ν˜ = 3434 br. s, 2960 m, 2925 m, 1652 s, 1600 vs, 1552 m, 1490 m,
1432 m, 1411 s, 1349 vs, 1255 m, 1103 m, 1031 w, 956 m, 767 w,
663 w, 628 m, 526 m cm–1.
1
Cu1–O1
Cu1–O2#1
Cu1–O3#1
O1–Cu1–O1#1
O1–Cu1–O2#1
O1–Cu1–O3#1
O2–Cu1–O3
O3–Cu1–O3#1
1.947(2)
1.986(2)
2.389(2)
180
94.01 (9)
82.16 (8)
85.41 (9)
180
Cu1–O1#1
Cu1–O2
Cu1–O3
O1–Cu1–O2
O1–Cu1–O3
O2–Cu1–O2#1 180
1.947(2)
1.986(2)
2.3892(2)
85.99 (9)
97.84 (8)
O2–Cu1–O3#1 94.59 (9)
2
{[Cu(1,3-BDC-Cl4)(H2O)3] (dioxane)·(H2O)}n (2). The same syn-
thetic procedure as that for 1 was used except that the solvents were
replaced by dioxane/H2O (v/ v, 1:1, 6 mL), giving blue block crystals
Cu1–O1
Cu1–O5
Cu1–O6
1.964(3)
2.257(3)
1.987(3)
87.0(2)
96.5(1)
177.2(1)
95.6(1)
90.8(1)
93.7(1)
85.4(1)
89.7(1)
Cu1–O3#1
Cu1–O5#2
Cu1–O7
O1–Cu1–O5
O1–Cu1–O6
O3#1–Cu1–O5 87.9(1)
O3#1–Cu1–O6 178.3(1)
O5–Cu1–O5#2 172.1(1)
O5#2–Cu1–O6 82.8(1)
1.984(3)
2.480(3)
1.973(3)
90.6(1)
of
2 in ca. 40% yield (21.1 mg, based on 1,3-H2BDC-Cl4).
O1–Cu1–O3#1
O1–Cu1–O5#2
O1–Cu1–O7
O3#1–Cu1–O5#2
O3#1–Cu1–O7
O5–Cu1–O6
O5#2–Cu1–O7
O6–Cu1–O7
C12H16Cl4CuO10: calcd. C 27.42; H 3.07%; found: C 27.85; H 3.03%.
IR (KBr): ν˜ = 3457 br. s, 2977 m, 2966 m, 2923 w, 1622 vs, 1548 m,
1444 w, 1415 m, 1396 s, 1344 vs, 1257 m, 1120 s, 1080 m, 1045 w,
952 w, 873 s, 831 w, 709 w, 638 s, 619 m, 541 w cm–1.
92.4(1)
X-ray Crystallography: Single-crystal X-ray diffraction measure-
ments of 1 and 2 were performed with a Bruker Apex II CCD dif-
fractometer at the ambient temperature with Mo-Kα radiation (λ =
0.71073 Å). In each case, a semiempirical absorption correction was
applied using SADABS,[26] and the program SAINT was used for inte-
gration of the diffraction profiles.[27] The structures were solved by the
direct methods using SHELXS program of SHELXTL packages and
refined anisotropically for all non-hydrogen atoms by full-matrix least-
O5–Cu1–O7
87.5(1)
Symmetry transformations used to generate equivalent atoms:
For 1, #1: –x+2, –y+1, –z+2. For 2, #1: –x+1/2, y+1/2, z;
#2: x+1/2, –y+3/2, –z+2.
Crystallographic data (excluding structure factors) for the structures in
this paper have been deposited with the Cambridge Crystallographic
Z. Anorg. Allg. Chem. 2014, 1810–1815
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
1811

S.-C. Chen, C.-P. Li, Q. Chen et al.
ARTICLE
Data Centre, CCDC, 12 Union Road, Cambridge CB21EZ, UK. Copies
of the data can be obtained free of charge on quoting the depository
numbers CCDC-981975 and CCDC-981976 for 1 and 2 (Fax:
+44-1223-336-033;
E-Mail:
deposit@ccdc.cam.ac.uk,
http://
www.ccdc.cam.ac.uk).
Results and Discussion
Syntheses and General Characterization
Considering the effect of crystalline solvent systems on
structural assemblies of coordination polymers,[29] our strategy
was to prepare new polymeric CuII complexes with a new per-
chlorinated ligand 1,3-H2BDC-Cl4 by changing the solvent
systems. Complexes 1 and 2 were synthesized in different sol-
vent systems (MeOH/DMF for 1 and dioxane/H2O for 2)
through the reaction of 1,3-H2BDC-Cl4 with Cu(NO3)2 under
ambient conditions. When Cu(NO3)2 was replaced by CuCl2,
Cu(OAc)2, or Cu(ClO4)2, both 1 and 2 could also be isolated
by the same procedure (confirmed by IR spectra and X-ray
analysis), which indicates that the final products are indepen-
dent of the counter-anions in such solvent systems. Both com-
plexes are stable at room temperature and insoluble in water
and common organic solvents, which is consistent with their
polymeric nature. Slight peak shifts and intensity in the PXRD
patterns (see Figure 1) can be attributed to differences in the
temperatures, at which data were acquired and the degree of
solvent loss from the samples. For the IR spectra of 1 and
2, the broad peak appearing in the region of 3000–3500 cm–1
corresponds to the O–H stretching frequencies. Both com-
plexes show characteristic bands of carboxylate groups appear-
ing in the region of 1590–1660 cm–1 for the antisymmetric
stretching vibrations and at 1340–1410 cm–1 for the symmetric
stretching vibrations, respectively. For 2, the strong character-
istic peaks around 873 and 1120 cm–1 can be assigned to the
ring valence vibrations of dioxane.[30] In addition, the absence
of strong adsorption band around 1712 cm–1 for the free 1,3-
H2BDC-Cl4 molecule indicates that the 1,3-H2BDC-Cl4 ligand
in 1 and 2 is completely deprotonated, which is consistent with
the consideration of charge balance.
Figure 1. Experimental and simulated PXRD patterns for complexes
1 (a) and 2 (b).
chlorinated benzene ring with dihedral angles of 90°, which
is obviously larger than those of other carboxylate complexes
constructed from 1,4-BDC-Cl4.[18,20,21,24] Each 1,3-BDC-Cl4
ligand connects four CuII ions with the two carboxylate groups
adopting a familiar bridging bis-bidentate mode, and the DMF
ligand is also a bridging ligand since the oxygen atoms of
DMF join successive CuII ions. Due to such unique connectiv-
ity, the distorted CuO6 octahedra are interlinked to each other
in a trans corner-sharing fashion to form an infinite 1D [–Cu–
DMF–COO–]n chain along the [010] direction, within which
the adjacent Cu···Cu separation is 3.631(2) Å and the
Cu···Cu···Cu angle is 180°. Each chain is connected to neigh-
boring parallel chains through the backbones of 1,3-BDC-Cl4,
resulting in a 2D coordination layer (Figure 2b). From the
Structure Descriptions of Complexes 1 and 2
{[Cu(1,3-BDC-Cl4)(DMF)] (H2O)}n (1)
Single-crystal X-ray diffraction analysis reveals that com- viewpoint of topology, each central CuII atom is regarded as a
plex 1 crystallizes in the monoclinic space group P21/m and 6-connected node to join four neighboring 4-connected 1,3-
exhibits a 2D layered structure. The asymmetric unit of 1 con- BDC-Cl4 nodes, and two adjacent central CuII atoms are also
tains one CuII ion, one 1,3-BDC-Cl4 dianion, one DMF ligand, linked through the carbonyl of DMF. Thus, the ligands and
and one guest water molecule. As depicted in Figure 2a, the metal atoms are interconnected to generate a 2D (4,6)-con-
central CuII atom is six-coordinate to four oxygen atoms (O1, nected network with the Schläfli symbol of (32.42.52)
O1#1, O2, and O2#1) from four different 1,3-BDC-Cl4 ligands (34.44.54.63). Furthermore, intermolecular Cl···Cl interactions
in the basal plane, and by two oxygen atoms (O3 and O3#2) (Cl2···Cl4i distance = 3.410(1) Å, i = x–1, y, z) were found to
from two DMF ligands occupying the axial positions. The ax- stabilize such 2D coordination motifs. It should be pointed out
ial elongated Cu–O distance is significantly longer than those that the Cl···Cl distance in 1 is shorter than twice the Pauling’s
in the basal plane (Table 2). Notably, owing to the steric hin- van der Waals radius of the chlorine atom (3.76 Å)[31] and that
drance of the bulky chlorine atoms, the two carboxylate groups stated by Bondi (3.52 Å).[32] With respect to the lattice water
within the 1,3-BDC-Cl4 ligand are perpendicular to the tetra- guest, it works as a linker to fabricate the 3D supramolecular
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© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2014, 1810–1815

2D Copper(II) Coordination Networks with Tetrachloro-1,3-benzenedicarboxylate
the Cl3 atoms and carboxylate O1 atoms of 1,3-BDC-Cl4, as
illustrated in Figure 2c.
Table 3. Possible hydrogen-bonding arrangements /Å,° in the crystal
structures of 1 and 2.
D–H···A
H···A D···A
D–H···A Symmetry code
1
O4–H4A···Cl3
C9–H9···Cl1
2
O5–H5B···O2
O7–H7B···O1
O5–H5A···O4
O6–H6A···O10 1.87
O6–H6B···O3
O7–H7A···O9
2.70
2.74
3.380(5) 138
3.669(4) 177
x, y, z–1
x+1, y, z
1.90
1.95
1.89
2.738(5) 167
2.786(5) 166
2.658(5) 149
2.714(5) 174
2.842(5) 163
2.682(7) 160
2.773(5) 140
2.903(5) 177
–x, –y+1, –z+2
x–1/2, –y+3/2, –z+2
–x+1, –y+1, –z+2
x–1/2, –y+3/2, –z+2
–x+1/2, y+1/2, z
–x+3/2, y+1/2, z
2.02
1.87
O10–H10A···O4 2.06
O10–H10B···O2 2.05
{[Cu(1,3-BDC-Cl4)(H2O)3] (dioxane)·(H2O)}n (2)
Crystallographic studies show that complex 2 crystallizes in
the orthorhombic space group Pbca and the asymmetric unit
contains one CuII ion, one 1,3-BDC-Cl4 dianion, two aqua li-
gands, one lattice dioxane molecule, and one water guest. In
the structure of 2 (see Figure 3a), the CuII ion has a distorted
octahedral environment (CuO6), consisting of two oxygen
atoms (O1 and O3#1) from two 1,3-BDC-Cl4 ligands and four
oxygen atoms (O5, O5#1, O6, and O7) from four aqua ligands
with the Cu–O distance in the range of 1.964(3)–2.480(3) Å.
In contrast to 1, each anionic 1,3-BDC-Cl4 in 2 takes the bis-
monodentate coordination fashion, where the rotation angles
between the carboxylates and the tetrachlorinated benzene ring
are 67.3(3)° and 68.5(3)°, respectively. Two adjacent CuII ions
are linked by one μ2-O atom of the aqua ligand to construct a
1D [Cu-H2O]n chain. Such 1D motifs are further extended by
1,3-BDC-Cl4 spacers to afford a 2D layer (Figure 3b). Thus,
the layers have the common 2D 4-connected (4,4) sql coordi-
nation net.[33] Furthermore, the included lattice water and diox-
ane molecules are found to interact with the 2D coordination
motifs by means of multiple O–H···O bonds such as
O5–H5A···O4, O6–H6A···O10, O6–H6B···O3, O7–H7A···O9,
O10–H10A···O4, and O10–H10B···O2 (see Table 3 for details),
which consolidate the 3D supramolecular lattice of 2.
Thermal Stability
Figure 2. View of (a) the coordination environment of the central
CuII atoms in 1. Symmetry codes: #1, x, –y+1/2, z; #2, –x+2, y–1/2,
– z+2; #3, –x+1, –y+1, – z+2; #4, x+1, y, z; #5, – x+2, –y+1, –z+2.
(b) The 2D coordination layer of 1 along the ab plane. (c) 3D supra-
molecular architecture. Hydrogen bonds interactions are shown as
dashed lines.
To investigate the thermal stabilities of complexes 1 and 2,
thermogravimetric analysis (TGA) experiments were taken
from room temperature to 800 °C. The corresponding curves
are depicted in Figure 4. For 1, the first weight loss of 19.2%
in the temperature range of 45–200 °C corresponds to the eli-
mination of coordinated DMF and lattice water molecules (cal-
culated: 19.9%). The residual solid starts to decompose at
architecture by connecting the neighboring layers through 215 °C with a series of consecutive weight losses that do not
intermolecular O–H···Cl and C–H···Cl hydrogen-bonding inter- stop until the heating end. The TGA curve for 2 shows the
actions (hydrogen bond parameters are listed in Table 3) with initial weight loss of 14.1% in the temperature range of 75–
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S.-C. Chen, C.-P. Li, Q. Chen et al.
ARTICLE
135 °C, which can be ascribed to the removal of three coordi-
nated and one lattice water molecules (calcd. 13.7%). The co-
ordination framework starts to decompose beyond 240 °C with
a series of weight losses.
Luminescent Properties
To explore their potential applications as luminescent crys-
talline materials, the emission spectra of complexes 1 and 2 as
well as the free ligand 1,3-H2BDC-Cl4 were recorded in the
solid state at room temperature (see Figure 5). Excitation of
the microcrystalline samples at 335 nm leads to the generation
of broad fluorescence emissions in the range of 450–530 nm.
The free ligand 1,3-H2BDC-Cl4 has a weak fluorescence emis-
sion band maximized at 476 nm, which can be ascribed to the
πǞπ* and/or nǞπ* transitions. In comparison with the spec-
trum of the 1,3-H2BDC-Cl4 ligand, 1 and 2 show similar
strong emission bands maximized at 479 nm for 1 and 477 nm
for 2, respectively. Obviously, the emission bands of both com-
plexes should come from the ligand-centered transitions, and
the slight redshift compared to that of 1,3-H2BDC-Cl4 may
result from the effect of metal-ligand coordination interactions.
Moreover, effective enhancement of their fluorescence inten-
sity in comparison with that of the free ligand may be attrib-
uted to the increased rigidity of 1,3-BDC-Cl4 when bound to
central CuII atoms, which will effectively reduce the loss of
energy.[34,35]
Figure 3. View of (a) the coordination environment of the central CuII
atoms in 2. Symmetry codes: #1, –x+1/2, y+1/2, z; #2, x+1/2, –y+3/
2, –z+2; #3, –x+1/2, y–1/2, z. (b) The 2D layered structure of 2 along
the ab plane.
Figure 5. Solid-state fluorescent emission spectra of complexes 1 and
2 as well as the free ligand 1,3-H2BDC-Cl4.
Conclusions
This work presents syntheses, crystal structures, and proper-
ties of two new 2D CuII coordination polymers based on a new
perchlorinated benzenedicarboxylate ligand 1,3-H2BDC-Cl4,
which may show different 1D CuII motifs such as [–Cu–DMF–
COO–]n chain (for 1) and [Cu–H2O]n chain (for 2) connected
with 1,3-BDC-Cl4 spacers to generate distinct 2D coordination
Figure 4. Thermogravimetric profiles for complexes 1 and 2.
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© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2014, 1810–1815

2D Copper(II) Coordination Networks with Tetrachloro-1,3-benzenedicarboxylate
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networks. Their structural diversity of such crystalline prod-
ucts may be regulated by the choice of solvent systems. Inves-
tigation on the crystal packing of both complexes suggests that
intermolecular O–H···O and O–H···Cl hydrogen-bonding inter-
actions may act as important driving forces for the self-as-
sembly of 3D supramolecular architectures. Further studies on
the effect of chlorine interactions on the construction of new
supramolecular frameworks based on various polychlorinated
organic ligands are underway in our laboratory.
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We gratefully acknowledge financial support by the National Natural
Science Foundation of China (21201026), the Nature Science Founda-
tion of Jiangsu Province (BK20131142), the Open Foundation of Ji-
angsu Province Key Laboratory of Fine Petrochemical Technology
(KF1105), and A Project Funded by the Priority Academic Program
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Received: January 30, 2014
Published Online: March 26, 2014
Z. Anorg. Allg. Chem. 2014, 1810–1815
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
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