Syntheses, structures and luminescence properties of two Cd(II) Complexes Based on 2-((1H-1,2,4-Triazol-1-yl)methyl)-1H-benzimidazole and aromatic polycarboxylate ligands

Article abstract of DOI:10.5560/ZNB.2012-0159

Two new Cd(II) complexes, {[Cd(m-bdc)(tmb)(H₂O)]·CH ₃OH}n (1) and {[Cd(t-bdc)(tmb)(H₂O)]·2H ₂O·DMF}n (2), have been prepared by using 2-((1H-1,2,4- triazol-1-yl)methyl)-1Hbenzimidazole (tmb) as a ligand in the presence of 1,3-benzenedicarboxylic acid (m-H₂bdc) or 1,4-benzenedicarboxylic acid (t-H₂bdc). Single-crystal X-ray diffraction exhibits that complex 1 displays a 2D structure constructed by tmb ligands in trans conformation and carboxylate groups in a chelating mode. The 2D structure of complex 2 is different from that of 1, in that the tmb ligands are in cis conformation, and the carboxylate groups are in both unidentate or chelating coordination mode at the Cd(II) centers. The luminescence properties of 1 and 2 in the solid state at room temperature have been studied.

Full text of DOI:10.5560/ZNB.2012-0159

Syntheses, Structures and Luminescence Properties of Two Cd(II)
Complexes Based on 2-((1H-1,2,4-Triazol-1-yl)methyl)-1H-benzimidazole
and Aromatic Polycarboxylate Ligands
Xiuxiu Wang, Xiao Han, Zhun Qiao, Guanghua Jin, and Xiangru Meng
The College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou
450052, P. R. China
Reprint requests to Prof. Xiangru Meng. Fax: +86-0371-67783126. E-mail: mxr@zzu.edu.cn
Z. Naturforsch. 2012, 67b, 783 – 790 / DOI: 10.5560/ZNB.2012-0159
Received May 4, 2012
Two new Cd(II) complexes, {[Cd(m-bdc)(tmb)(H2O)]·CH3OH}n (1) and {[Cd(t-bdc)(tmb)(H2O)]
·2H2O·DMF}n (2), have been prepared by using 2-((1H-1,2,4-triazol-1-yl)methyl)-1H-
benzimidazole (tmb) as a ligand in the presence of 1,3-benzenedicarboxylic acid (m-H2bdc)
or 1,4-benzenedicarboxylic acid (t-H2bdc). Single-crystal X-ray diffraction exhibits that complex 1
displays a 2D structure constructed by tmb ligands in trans conformation and carboxylate groups in
a chelating mode. The 2D structure of complex 2 is different from that of 1, in that the tmb ligands
are in cis conformation, and the carboxylate groups are in both unidentate or chelating coordination
mode at the Cd(II) centers. The luminescence properties of 1 and 2 in the solid state at room
temperature have been studied.
Key words: Cd(II) Complex, 2-((1H-1,2,4-Triazol-1-yl)methyl)-1H-benzimidazole, Crystal
Structure, Luminescence, Benzenedicarboxylate
Introduction
and 1,2,4,5-benzenetetracarboxylic acid have been
widely studied because of the diversity of coordination
The structures of metal-organic frameworks modes and the pH-sensitivity of the carboxylate
(MOFs) are affected by the choice of the coordi- groups [11]. Aromatic polycarboxylic acids can be
nation geometry of metal centers, the coordination partially or fully deprotonated to adopt different coor-
behavior of the multifunctional organic ligands and dination modes in their reactions with metal ions, and
auxiliary ligands, the reaction temperature, the pH they can act not only as hydrogen bond acceptors but
values, and the solvent system [1, 2]. The selection also as hydrogen bond donors to form supramolecular
of the organic ligand plays an important role in structures or allow for guest structures by hydrogen
the construction of complexes because the change bonding interactions [12].
in the type of bridging units, the flexibility of the
Cd(II) ions are able to coordinate simultaneously to
molecular backbone, the conformational preference, both oxygen- and nitrogen-containing ligands. A great
and the symmetry of organic ligands can lead to number of Cd(II) complexes containing both aro-
remarkable classes of materials bearing diverse matic carboxylates and N-heterocyclic ligands have
architectures and functions [3, 4]. For example, been reported [11]. For this contribution we chose
multifunctional N-heterocyclic ligands 1,2-bis(4- the flexible N-heterocyclic ligand 2-((1H-1,2,4-triazol-
pyridyl)-ethane [5, 6], 1,2-di(4-pyridyl)ethenes [7], 1-yl)methyl)-1H-benzimidazole (tmb) as the bridg-
1,3-bi(4-pyridyl)propane [8 – 10] etc. can coordinate ing ligand and 1,3-benzenedicarboxylic (m-H2bdc)
to transition metal ions to produce unique struc- or 1,4-benzenedicarboxylic acid (t-H2bdc) as auxil-
tural motifs with beautiful aesthetics and useful iary ligands in order to construct d10 transition metal
functional properties. Furthermore, MOFs based complexes, and to explore mixed-ligand Cd(II) com-
on aromatic polycarboxylic acid ligands, such as plexes constructed from aromatic carboxylate and
1,2-benzenedicarboxylic,
1,3-benzenedicarboxylic, N-heterocyclic ligands. Herein, we report the crys-
1,4-benzenedicarboxylic, 1,3,5-benzenetricarboxylic, tal structures and luminescence properties of two
c
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X. Wang et al. · Cd(II) Complexes
new complexes, {[Cd(m-bdc)(tmb)(H2O)]·CH3OH}n 3.51, N 13.49. – FT-IR (KBr, cm−1): ν = 3410 (m), 3118
(s), 1607 (s), 1548 (s), 1515 (s), 1462 (m), 1444 (s), 1398
(m), 1378 (s), 1284 (m), 1226 (m), 1120 (s), 1024 (s), 844
(1) and {[Cd(t-bdc)(tmb)(H2O)]·2H2O·DMF}n (2).
(m), 739 (s), 671 (m).
Experimental Section
Synthesis of {[Cd(t-bdc)(tmb) (H2O)]·2H2O·DMF}n (2)
All chemicals were of reagent grade quality obtained
from commercial sources and used without further pu-
The preparation of 2 was similar to that of 1 except
rification. The ligand 2-((1H-1,2,4-triazol-1-yl)methyl)-1H-
that 1,4-benzenedicarboxylic acid (t-H2bdc) was used in-
benzimidazole (tmb) was synthesized as reported previ-
ously [13]. Carbon, hydrogen and nitrogen analyses were
carried out on a Flash EA 1112 elemental analyzer. IR data
stead of 1,3-benzenedicarboxylic acid. Crystals of {[Cd(t-
bdc)(tmb)(H2O)]·2H2O·DMF}n suitable for X-ray analysis
were obtained. Yield: 57%. – Anal. for C21H26CdN6O8
were recorded on a Bruker Tensor 27 spectrophotometer with
(602.88): calcd. C 41.83, H 4.36, N 13.94; found C 41.64,
KBr pellets in the 400 – 4000 cm−1 region. Steady-state lu-
H 4.47, N 13.78. – FT-IR (KBr, cm−1): ν = 3372 (m), 3146
minescence measurements were performed using a Fluoro
Max-P spectrofluorimeter at room temperature in the solid
(m), 1669 (s), 1566 (s), 1499 (m), 1463 (m), 1384 (s), 1367
(s), 1287 (m), 1276 (m), 842 (m), 751 (s).
state.
Single-crystal structure determination
Synthesis of {[Cd(m-bdc)(tmb)(H2O)]·CH3OH}n (1)
A mixture of ligand tmb (0.05 mmol), CdCl2·2.5H2O
Suitable single crystals of 1 and 2 were carefully se-
(0.05 mmol), 1,3-benzenedicarboxylic acid (m-H2bdc) lected and glued to thin glass fibers. X-Ray data collections
(0.05 mmol), H2O (6 mL), CH3OH (2 mL), and DMF were performed on a Rigaku Saturn 724 CCD area detec-
(1 mL) was poured into a Parr Teflon-lined stainless-steel tor equipped with a graphite monochromator (MoKα radia-
˚
vessel (25 mL). Then the vessel was sealed and heated tion; λ = 0.71073 A; operating at 50 kV and 40 mA). The
to 120 ◦C for 3 d. The autoclave was cooled to room data were collected in the ω-scan mode at a temperature of
temperature at a rate of 10 ◦C·h−1. Crystals of {[Cd(m- 293(2) K. The crystal-to-detector distance was 45 mm. An
bdc)(tmb)(H2O)]·CH3OH}n suitable for X-ray analysis empirical absorption correction was applied. The data were
were collected. Yield: 51%. – Anal. for C19H19CdN5O6 corrected for Lorentz and polarization effects. The struc-
(525.79): calcd. C 40.40, H 3.65, N 13.32; found C 40.66, H tures were solved by Direct Methods and completed by dif-
Table 1. Crystallographic
data and structure refine-
Complex
1
2
Empirical formula
Formula weight
Temperature, K
Crystal size, mm3
Crystal system
Space group
C19H19CdN5O6
525.79
293(2)
C21H26CdN6O8
602.88
293(2)
ment details for
1 and
2.
0.19 × 0.18 × 0.15
0.20 × 0.17 × 0.16
triclinic
triclinic
¯
¯
P1
P1
˚
a, A
8.1745(16)
10.034(2)
13.195(3)
107.10(3)
97.84(3)
96.55(3)
1011.1(4)
2
10.237(2)
11.057(2)
11.529(2)
93.36(3)
˚
b, A
˚
c, A
α, deg
β, deg
γ, deg
95.30(3)
108.21(3)
1228.9(4)
2
1.63
0.9
3
˚
Volume, A
Z
Calculated density, g cm−3
Absorption coefficient, mm−1
F(000), e
1.73
1.1
528
612
θ range for data collection, deg
hkl range
2.15 – 26.00
±10,−12 → 11, ±16
10987 / 3966 / 0.0470
3966 / 282
0.0500 / 0.1073
0.0566 / 0.1126
1.121
2.37 – 25.50
±12,−13 → 12, −10 → 13
11816 / 4480 / 0.0225
4480 / 325
0.0256 / 0.0643
0.0292 / 0.0663
1.034
Reflections collected / unique / Rint
Data / ref. parameters
Final R1 / wR2 [I > 2 σ(I)]
Final R1 /wR2 (all data)
Goodness-of-fit on F2
−3
˚
∆ρfin (max / min), e A
0.81 / −0.97
0.47 / −0.48
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X. Wang et al. · Cd(II) Complexes
785
ference Fourier syntheses and refined by full-matrix least- tallographic crystal data and structure processing parameters
squares using the SHELXS/L-97 program package [14]. All for complexes 1 and 2 are summarized in detail in Table 1.
non-hydrogen atoms were refined anisotropically. The hy- Selected bond lengths and bond angles are listed in Table 2.
drogen atoms were positioned geometrically and refined us- Hydrogen bond parameters are listed in Table 3.
ing a riding model. The hydrogen atoms were assigned with
CCDC 877998 (1) and 877999 (2) contain the supple-
common isotropic displacement parameters and included in mentary crystallographic data for this paper. These data can
the final refinement by using geometrical restraints. Crys- be obtained free of charge from The Cambridge Crystallo-
˚
Table 2. Selected bond lengths (A) and
Complex 1
Cd1–N4#1
Cd1–N1
Cd1–O2
Cd1–O5
2.312(4)
2.340(4)
2.341(4)
2.366(3)
Cd1–O4#2
2.392(4)
2.481(3)
2.544(3)
angles (deg) for 1 and 2 with estimated
standard deviations in parenthesesa.
Cd1–O1
Cd1–O3#2
O1–Cd1–O3#2
N4#1–Cd1–O2
N4#1–Cd1–O5
O2–Cd1–O5
N1–Cd1–O4#2
O5–Cd1–O4#2
N1–Cd1–O1
O5–Cd1–O1
N4#1–Cd1–3#2
O2–Cd1–O3#2
O4#2–Cd1–O3#2
176.09(12)
144.96(13)
86.05(12)
96.81(13)
93.54(14)
87.97(14)
101.81(14)
84.63(14)
85.86(12)
128.72(12)
52.25(11)
N4#1–Cd1–N1
N1–Cd1–O2
N1–Cd1–O5
N4#1–Cd1–O4#2
O2–Cd1–O4#2
N4#1–Cd1–O1
O2–Cd1–O1
O4#2–Cd1–O1
N1–Cd1–O3#2
O5–Cd1–O3#2
86.26(13)
93.02(14)
170.14(12)
137.44(13)
77.60(12)
92.10(13)
53.73(12)
129.20(12)
81.40(13)
91.90(12)
Complex 2
Cd1–O3
2.3098(17)
2.322(2)
2.328(2)
100.01(7)
81.00(8)
88.20(8)
83.40(7)
88.23(8)
134.28(7)
82.68(7)
93.08(8)
Cd1–O2
Cd1–N1
Cd1–O1
2.374(2)
2.381(2)
2.479(2)
142.32(7)
83.40(7)
134.11(7)
166.32(7)
105.38(8)
93.86(8)
53.55(7)
Cd1–O5
Cd1–N4#1
O3–Cd1–O5
O5–Cd1–N4#1
O5–Cd1–O2
O3–Cd1–N1
N4#1–Cd1–N1
O3–Cd1–O1
N4#1–Cd1–O1
N1–Cd1–O1
O3–Cd1–N4#1
O3–Cd1–O2
N4#1–Cd1–O2
O5–Cd1–N1
O2–Cd1–N1
O5–Cd1–O1
O2–Cd1–O1
a
Symmetry transformations used to generate equivalent atoms: 1: #1 x+1, y, z; #2 x, y−1,
z; 2: #1 −x+1, −y+2, −z+2.
Table 3. Hydrogen bonds
˚
˚
˚
D–H···A
d(D–H) (A)
d(H···A) (A)
d(D···A) (A)
(D–H···A)(deg)
for 1 and 2a.
Complex 1
1.84
O6–H6···O3#3
0.82
0.86
0.85
0.85
2.658(5)
2.716(5)
2.691(5)
2.702(5)
172.3
159.9
155.6
148.4
N5–H5A···O6#5
O5–H1W···O2#6
O5–H2W···O4#7
1.89
1.89
1.94
Complex 2
1.90
O5–H2W···O6
O6–H3W···O7
O7–H5W···O8
O7–H6W···O2
N2–H2A···O3#4
O5–H1W···O4#5
O6–H4W···O7#6
0.85
0.85
0.85
0.85
0.86
0.85
0.85
2.731(3)
2.816(4)
2.716(4)
2.752(3)
2.760(3)
2.789(3)
2.864(4)
166.8
151.8
176.5
164.5
156.3
174.3
167.3
2.04
1.87
1.92
1.95
1.94
2.03
Symmetry transformations used to generate equivalent atoms: 1: #3 x − 1, y, z; #5 −x + 1, −y + 1, −z;
a
−x + 3, −y + 1, −z + 1; #7 −x + 3, −y + 2, −z + 1; 2: #4 −x + 2, −y + 2, −z + 2; #5 −x + 1, −y + 1,
#6
−z+2; #6 −x+1, −y+1, −z+1.
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786
X. Wang et al. · Cd(II) Complexes
graphic Data Centre via www.ccdc.cam.ac.uk/data request/
cif.
Results and Discussion
IR spectra of complexes 1 and 2
The IR spectra exhibit absorption bands at
3410 cm−1 for 1 and at 3372 cm−1 for 2 associ-
ated with the stretching vibrations of the hydroxyl
groups, and absorption bands at 3118 cm−1 for 1
and at 3146 cm−1 for 2 attributed to Ar-H stretch-
ing vibrations [15]. The absorption band observed at
1669 cm−1 is corresponding to the non-coordinated
DMF molecule [16]. Furthermore, the absorption
bands at 1607, 1548, 1462, and 1444 cm−1 for 1 and
at 1566, 1499 and 1463 cm−1 for 2 originate from
C=C and C=N stretching vibrations [17, 18]. The ab-
sorption bands at 739 cm−1 for 1 and at 751 cm−1
for 2 can be assigned to characteristic stretching vi-
brations of o-phenylene [19]. The absorption band
at 671 cm−1 for 1 can be attributed to the stretch-
ing vibrations of m-phenylene, and that at 842 cm−1
for 2 corresponds to the stretching vibrations of t-
phenylene [20]. Separations (∆) between νa(COO) and
νs(COO) are different for the unidentate, chelating
(bidentate) and bridging complexation. In 1, the sepa-
ration (∆) between νa(COO) and νs(COO) is 53 cm−1
(1515, 1462 cm−1), and the carboxylate groups are
thus chelating the Cd(II) center. In 2, unidentate and
chelating carboxylate groups are mixed; the uniden-
tate carboxylate group shows νa(COO) and νs(COO)
at 1566 and 1384 cm−1 (∆ = 182 cm−1) [20], while
the chelating carboxylate group displays νa(COO) and
νs(COO) at 1499 and 1463 cm−1 (∆ = 32 cm−1), re-
spectively. The above analyses are confirmed by the
determination of the molecular structure.
The structure of {[Cd(m-bdc)(tmb)(H2O)]·CH3OH}n
(1)
Single-crystal X-ray analysis has revealed that com-
¯
plex 1 crystallizes in the triclinic space group P1 with
Fig. 1. (a) Coordination environment of Cd(II) in 1 with el-
lipsoids drawn at the 30% probability level; hydrogen atoms
and free methanol molecules have been omitted for clarity;
(b) view of the 2D structure of complex 1; (c) view of the
packing of the building unit of complex 1 in the solid state
supported by hydrogen bonds and π···π interactions.
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X. Wang et al. · Cd(II) Complexes
787
Fig. 2. (a) View of the coordination environ-
ment of the Cd(II) center and the dinuclear
structure connected by tmb ligands in complex
2 with ellipsoids drawn at the 30% probability
level; hydrogen atoms and free water and DMF
molecules were omitted for clarity; (b) view of
the 2D network of complex 2; (c) 3D structure
of complex 2 in the solid state supported by
hydrogen bonds.
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788
X. Wang et al. · Cd(II) Complexes
Z = 2. As shown in Fig. 1a, the Cd(II) center is hepta- a unidentate fashion. The other carboxylate group co-
coordinated in a distorted pentagonal-biyramidal ge- ordinates to a neighboring Cd(II) center in a chelating
ometry. Four O atoms (O1, O2, O3#2, O4#2) from coordination mode, whereas in 1 both of the carboxy-
two chelating carboxylate groups as well as one N lates of the 1,3-benzenedicarboxylate ligand coordi-
atom from the benzimidazole ring occupy the equa- nate to Cd(II) in a chelating fashion. Furthermore, in 2
torial positions (the mean deviation from the plane each tmb ligand coordinates to Cd(II) centers in a trans
˚
is 0.1169 A), and one N atom from a triazole ring conformation with the N1–C15–C16–N6 torsion an-
together with one O atom from a coordinated water gle of 80.0◦, while the tmb ligands are coordinated to
molecule are located in the apical positions (the N1– Cd(II) centers in the cis conformation in 1. Fig. 2a dis-
Cd1–O5 bond angle is 170.14(12)◦). The Cd–O and plays the coordination environment of the Cd(II) cen-
Cd–N distances are in the ranges 2.341(4) – 2.544(3) ter. It is hexa-coordinated by four O atoms and two N
˚
and 2.312(4) – 2.340(4) A, and they are similar to the atoms to give rise to a severely distorted octahedral ge-
results for other Cd(II) complexes [21 – 24]. The coor- ometry. The equatorial positions are occupied by three
dinated carboxylate groups are statistically different in O atoms from one unidentate carboxylate group and
that for O1, O2 (or O3#2, O4#2), the Cd–O distances one chelating carboxylate group and one N atom from
˚
˚
are 2.481(3), 2.341(4) A (or 2.544(3) and 2.392(4) A), a triazole ring, and the mean deviation from the plane
˚
respectively, suggesting that the pentagonal bipyramid is 0.1521 A. One O atom from the coordinated wa-
is distorted. In complex 1, each tmb ligand adopts the ter molecule as well as one N atom from a benzimid-
trans conformation with the N3–C3–C4–N4 torsion azole ring occupy the apical positions, and the O5–
angle of –126.9◦ and links two Cd(II) centers paral- Cd1–N1 bond angle is 166.32(7)◦. The distances Cd–
lel to the crystallographic a direction forming a chain O and Cd–N are in the ranges 2.3098(17) – 2.479(2)
˚
(·· ·Cd-tmb-Cd·· ·) (Fig. 1b). The intra-chain Cd· ··Cd and 2.328(2) – 2.381(2) A, respectively. They are sim-
˚
distance via the ligand tmb is 8.174 A. The m-H2bdc ilar to those in 1 and to the results for other Cd(II)
ligand is completely deprotonated, and the carboxylate complexes [21 – 24]. In 2, Cd1 and Cd1#1 are bridged
groups coordinated to the Cd(II) centers in the chelat- by two tmb ligands leading to a dinuclear structure
ing mode. The chains are further linked by the m-bdc2− [Cd2(tmb)2], in which the Cd1· · ·Cd1#1 distance is
˚
groups parallel to the b direction to give rise to a 2D 6.571 A as shown in Fig. 2a. The dimers are bridged by
structure of “fields” shape, as shown in Fig. 1b. The unidentate carboxylate groups leading to a chain par-
distance Cd···Cd via the m-bdc2− groups is 10.034 A. allel to the crystallographic a direction. These chains
˚
In addition, there are π· · ·π interactions between the are linked by chelating carboxylate groups form-
˚
benzene rings (the distance between them is 3.449 A) ing a 2D grid structure as shown in Fig. 2b. Addi-
of the m-bdc2− groups in adjacent layers [17]. There tionally, there are six kinds of hydrogen bonds be-
are three kinds of hydrogen bonds between coordi- tween the coordinating water molecules and carboxy-
nating water molecules and carboxylate groups, be- late groups, between coordinating water molecules
tween non-coordinating water molecules and carboxy- and non-coordinating water molecules, between non-
late ions, and between N atoms from benzimidazole coordinating water molecules and carboxylate groups,
rings and CH3OH molecules. The layers are stacked between non-coordinating water molecules and DMF
via hydrogen bonds, and the π···π interactions lead to molecules, between non-coordinating water molecules
a 3D structure (Fig. 1c).
and non-coordinating water molecules, and between
N atoms from benzimidazole rings and carboxylate
groups. Through these hydrogen bonds these layers are
further stacked into a 3D framework (Fig. 2c).
The structure of
{[Cd(t-bdc)(tmb)(H2O)]·2H2O·DMF}n (2)
Substitution of 1,4-benzenedicarboxylic acid in Luminescence properties
2 for 1,3-benzenedicarboxylic acid in 1 results in
a different crystal and molecular structure. The
Because metal-organic complexes constructed from
single-crystal X-ray analysis shows that the 1,4- d10 metal centers and organic ligands are promis-
benzenedicarboxylate ligand in 2 coordinates with ing candidates for hybrid photoactive materials with
one of its carboxylate groups to one Cd(II) center in potential applications e. g. in light-emitting diodes
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X. Wang et al. · Cd(II) Complexes
789
m-H2bdc
ligands, the emissions of complexes 1 and 2 show
bathochromic shifts, which may be assigned to in-
traligand π → π∗ transitions, the same as in the free
ligands. The N-donor and O-donor ligands contribute
to the fluorescence of the two complexes simultane-
ously [30].
tmb
Complex 2
Complex 1
Conclusion
t-H2bdc
In summary, we have isolated two new com-
plexes resulting from flexible N-heterocyclic lig-
ands and a Cd(II) salt in the presence of 1,3-
benzenedicarboxylic or 1,4-benzenedicarboxylic acid.
Because of the difference of the auxiliary ligands,
the 2-((1H-1,2,4-triazol-1-yl)methyl)-1H-benzimida-
zole ligand adopts different conformations, which lead
to different crystal and molecular structures of 1 and 2.
In complex 1, tmb ligands coordinate to Cd(II) centers
with a trans conformation, while a cis conformation is
adopted to connect to Cd(II) centers in 2. The present
results demonstrate that an auxiliary ligand plays an
important role in the construction of the frameworks.
If one introduces other auxiliary ligands into the reac-
tion systems, new complexes with interesting structure
may be obtained.
300
350
400
450
500
550
Wavelength (nm)
Fig. 3. Solid-state emission spectra of the free ligands, and
complexes 1 and 2 at room temperature.
(LEDs) [25 – 29], the emission spectra of both com-
plexes have been investigated in the solid state at room
temperature (Fig. 3). Complexes 1 and 2 show lumi-
nescence at 450 nm (λex = 389 nm) and 391 nm (λex
=
346 nm), respectively. To further analyze the nature
of the emission bands, the luminescence properties of
the ligand tmb and of the auxiliary ligands m-H2bdc
and t-H2bdc have also been investigated in the solid
state at room temperature. The emission peaks occur
Acknowledgement
at 378 nm (λex = 335 nm) for tmb, 363 nm (λex
=
We gratefully acknowledge the financial support by
the National Natural Science Foundation of China (no.
292 nm) for m-H2bdc and 384 nm (λex = 329 nm) for
t-H2bdc. Compared to the emission bands of the free J0830412).
[1] C. C. Wang, S. M. Tseng, S. Y. Lin, F. C. Liu, S. C. Dai,
G. H. Lee, W. J. Shih, H. S. Sheu, Cryst. Growth & Des.
2007, 7, 1783.
[2] P. Zhang, D. S. Li, J. Zhao, Y. P. Wu, C. Li, K. Zou,
J. Y. Lu, J. Coord. Chem. 2011, 64, 2329.
[3] Y. Wan, L. Zhang, L. Jin, S. Gao, S. Lu, Inorg. Chem.
2003, 42, 4985.
[4] M. Eddaoudi, J. Kim, J. B. Wachter, H. K. Chae, M.
O’Keeffe, O. M. Yaghi, J. Am. Chem. Soc. 2001, 123,
4368.
[9] L. Pan, E. B. Woodlock, X. Wang, K. C. Lam,
A. L. Rheingold, Chem. Commun. 2001, 1762.
[10] M. L. Tong, Y. M. Wu, J. Ru, X. M. Chen, H. C. Chang,
S. Kitagawa, Inorg. Chem. 2002, 41, 4846.
[11] J. D. Lin, J. W. Cheng, S. W. Du, Cryst. Growth & Des.
2008, 8, 3345.
[12] F. Oscar, P. Jorge, C. D. Laura, S. D. Fernando, L. Ana,
L. Francesc, J. Miguel, R. P. Catalina, Cryst. Growth &
Des. 2008, 8, 3984.
[13] R. Pellicciari, Synth. Commun. 1981, 629.
[5] E. Suresh, M. M. Bhadbhade, CrystEngComm 2001, 3, [14] G. M. Sheldrick, SHELXS/L-97, Programs for Crys-
50.
tal Structure Determination, University of Go¨ttingen,
Go¨ttingen (Germany) 1997. See also: G. M. Sheldrick,
Acta Crystallogr. 1990, A46, 467; ibid. 2008, A64, 112.
[15] S. X. Yan, D. Zhao, T. Li, R. Wang, X. R. Meng, J. Co-
ord. Chem. 2012, 65, 945.
[6] D. Ghoshai, T. K. Maji, G. Mostafa, T. H. Lu,
N. R. Chaudhuri, Cryst. Growth & Des. 2003, 3,
9.
[7] M. C. Brandys, R. J. Puddephatt, Chem. Commun.
2001, 1508.
[16] J. Q. Chen,
Y. P. Cai,
H. C. Fang,
Z. Y. Zhou,
[8] F. M. Tabellion, S. R. Seidel, A. M. Arif, P. J. Stang,
Angew. Chem. Int. Ed. 2001, 40, 1529.
X. L. Zhan, G. Zhao, Z. Zhang, Cryst. Growth &
Des. 2009, 9, 1605.
Unauthenticated
Download Date | 3/15/17 12:31 PM

790
X. Wang et al. · Cd(II) Complexes
[17] A. Majumder, V. Gramlich, G. M. Rosair, S. R. Bat- [24] S. Wang, H. Xing, Y. Z. Li, J. F. Bai, Y. Pan, M. Scheer,
ten, J. D. Masuda, M. S. El Fallah, J. Ribas, J. P. Sutter, X. Z. You, Eur. J. Inorg. Chem. 2006, 3041.
C. Desplanches, S. Mitra, Cryst. Growth & Des. 2006, [25] B. Valeur, Molecular Fluorescence: Principles and Ap-
6, 2355. plications, Wiley-VCH, Weinheim, 2001.
[18] G. H. Jin, Y. Yang, X. L. Zhou, X. R. Meng, Z. Natur- [26] Y. Qiu, Y. Li, G. Peng, J. Cai, L. Jin, L. Ma, H. Deng,
forsch. 2012, 67b, 29.
[19] X. R. Meng, W. Zhou, Y. F. Qi, H. W. Hou, Y. T. Fan, J.
M. Zeller, S. R. Batten, Cryst. Growth & Des. 2010,
10, 1332.
Organomet. Chem. 2010, 695, 766.
[27] L. L. Liang, S. B. Ren, J. Zhang, Y. Z. Li, H. B. Du,
X. Z. You, Cryst. Growth & Des. 2010, 10, 1307.
[20] K. Nakamoto. Infrared and Raman Spectra of Inor-
ganic and Coordination Compounds, Part B, 6th ed., [28] L. P. Zhang, J. F. Ma, J. Yang, Y. Y. Pang, J. C. Ma, In-
John Wiley, Hoboken, New Jersey, 2009.
[21] F. A. A. Paz, J. Klinowski, Chem. Commun. 2003, [29] W. Liu, L. Ye, X. Liu, L. Yuan, J. Jiang, C. Yan, Cryst-
1484. EngComm 2008, 10, 1395.
[22] F. A. A. Paz, J. Klinowski, Inorg. Chem. 2004, 43, [30] Y. Y. Liu, J. F. Ma, J. Yang, Z. M. Su, Inorg. Chem.
org. Chem. 2010, 49, 1535.
3948.
2007, 46, 3027.
[23] F. A. A. Paz, J. Klinowski, Inorg. Chem. 2004, 43,
3882.
Unauthenticated
Download Date | 3/15/17 12:31 PM