Synthesis, crystal structure, and fluorescent property of [ZnII(Pta)2(4,4′-Bipy)(H2O)2] n1

Article abstract of DOI:10.1134/S1070328415070064

A coordination polymer of [Zn^II(Pta)₂(4,4′-Bipy)(H₂O)₂] _n (HPta = 2-(4-phenyl-1H-1,2,3-triazol-1-yl)acetic acid, 4,4′-Bipy = 4,4′-bipyridine) was synthesized and characterized by IR, fluorescence spec

Full text of DOI:10.1134/S1070328415070064

ISSN 1070ꢀ3284, Russian Journal of Coordination Chemistry, 2015, Vol. 41, No. 7, pp. 447–450. © Pleiades Publishing, Ltd., 2015.
Synthesis, Crystal Structure, and Fluorescent Property
1
of [ZnII(Pta)2(4,4'ꢀBipy)(H2O)2]n
C. L. Ma, J. Wu, and Y. F. Chen*
School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan, 430073 P.R. China
*eꢀmail: chyfch@hotmail.com
Received November 17, 2014
Abstract—A coordination polymer of [ZnII(Pta)2(4,4'ꢀBipy)(H2O)2]n (HPta = 2ꢀ(4ꢀphenylꢀ1
zolꢀ1ꢀyl)acetic acid, 4,4'ꢀBipy = 4,4'ꢀbipyridine) was synthesized and characterized by IR, fluorescence
spectroscopy and Xꢀray single crystal diffraction (CIF file CCDC no. 1001498). The complex crystallizes in
triclinic, space group with = 5.574(2), = 11.514(5), = 12.140(5) Å, = 64.653(6)°, = 86.859(8)°,
= 700.6(5) Å3, ρc = 1.569 g/cm3,
= 1, C30H28N8O6Zn, Mr = 661.97, (000) = 342,
0.938 mm–1, the final
= 0.0578 and wR = 0.1241 for 4876 observed reflections with I > 2σ ). In this comꢀ
Hꢀ1,2,3ꢀtriaꢀ
a
b
c
α
β
P1
γ
= 84.282(7)°,
V
Z
F
μ
=
R
(I
plex, the 1,2,3ꢀtriazoleꢀcarboxylic acid ligand, which only supplies a carboxylic anion to coordinate with
Zn2+ ions, while the nitrogen atoms of 1,2,3ꢀtriazole don’t coordinate with Zn2+ ions, the 4,4'ꢀbipyridine
ligand serves as a linker to form a 1D chain structure, the abundant hydrogen bonding which plays an imporꢀ
tant role in forming 2D structure. Compared with free HPta and 4,4'ꢀBipy, the intensity of fluorescence of
Pta with Zn(OAc)2 and 4,4'ꢀBipy with Zn(OAc)2 enhanced. However, the complex displays fluorescence
quenching, which probably be caused by charge transfer which due to HPta and 4,4'ꢀBipy mutual coordinaꢀ
tion with Zn(II).
DOI: 10.1134/S1070328415070064
1
INTRODUCTION
condition. The fluorescence properties of the complex
and free ligands were investigated, the results revealed
that the fluorescence quenching occurred for this
complex (the fluorescence enhancement for Zn(II)
with single free ligands), which probably be caused by
the HPta and 4,4'ꢀBipy mutual coordination with
Zn(II).
With the development of the Cu(I)ꢀcatalyzed
azideꢀalkyne cycloaddition (CuAAC) reaction [1], the
1,2,3ꢀtriazole has become a popular building block in
many fields, such as pharmaceutical research [2],
materials chemistry [3] and bioconjugation [4]. More
recently, the 1,2,3ꢀtriazoles also served as ligand to
form the 1,2,3ꢀtriazoleꢀbased metal complexes with
different metals, such as Cu [5], Zn [6], Co [7], Ni [8],
Pd [9], etc. [10], some of them show unique properꢀ
ties. For the abundant coordination nitrogen atoms
and high electron density of the 1,2,3ꢀtriazole ring
together with their strong stability, the 1,2,3ꢀtriazoles
can be a good candidate ligand for the synthesis of new
metal complexes.
EXPERIMENTAL
Materials and physical measurement. All chemiꢀ
cals were purchased from commercial available and
used without further purification. FTꢀIR spectrum
was recorded from KBr pellets and the range of 500–
4000 cm–1 on a Nicolet IS50ꢀIR spectrometer.
1H NMR spectra were recorded on Varian Mercury
400 MHz spectrometer. Chemical shifts were reported
relative to internal tetramethylsilane (TMS)
At the same time, 4,4'ꢀbipyridine (4,4'ꢀBipy),
which is a rigid bidentate spacer, has been extensively
used as bridging group along with proper metal ions
resulting in conjugation with other coꢀligands [11].
Mostly, complexes bridged by 4,4'ꢀBipy have interestꢀ
ing supraꢀmolecular architectures owing to its coordiꢀ
nation interactions [12]. In this paper, we synthesized
1
(0.00 ppm) or DMSOꢀd6 (2.50 ppm) for H NMR.
Melting points were measured on a melting point
tester RYꢀ1G apparatus. The liquidꢀstate fluorescence
emission/excitation spectra were recorded on a Hitaꢀ
chi Fꢀ7500 fluorescence spectrophotometer equipped
a Zn(II) coordination polymer [ZnII(Pta)2(4,4
'ꢀ
with a continuous Xeꢀ900 xenon lamp and a F900
μ
microsecond flash lamp. Crystal determination was
performed with a Bruker SMART APEX II CCD difꢀ
fractometer equipped with graphiteꢀmonochromaꢀ
Bipy)(H2O)2]n (I) by the mixing the 2ꢀ(4ꢀphenylꢀ1Hꢀ
1,2,3ꢀtriazolꢀ1ꢀyl)acetic acid (HPta) and 4,4'ꢀBipy
ligand with the Zn(OAc)2 under the hydrothermal
tized Mo
K
radiation (
λ
= 0.71073 Å), structure were
α
1
The article is published in the original.
solved by direct method using SHELXL program and
447

448
MA et al.
Table 1. Crystallographic data and structure refinement for complex
I
Parameter
Crystal system
Value
Triclinic
Space group
P1
a
b
, Å
, Å
5.574 (2)
11.514(5)
12.140(5)
64.653(6)
86.859(8)
84.282(7)
700.6(5)
1
c
α
, Å
, deg
, deg
β
γ
, deg
V, Å3
Z
ρcalcd, g cm–3
Crystal size, mm
1.569
0.1
×
0.1 0.1
×
F
μ
(000)
342
(MoK
), mm–1
0.938
1.86–24.99
6, –13 13, –14
α
θ
Range for data collection, deg
Index range
Type of scan
Reflections collected
h
,
k
,
l
–6
≤
h
≤
≤
k
≤
≤
l ≤ 14
Multiꢀscan
4876
Independent reflections, Rint
0.0591
0.1241
2423
Reflections with
I
> 2 , I
σ
Number of refinement parameters
Goodnessꢀofꢀfit on F2
1.055
Final R1
R1 wR2, all data**
Δρmax and Δρmin
,
wR2
,
I
> 2
σ
, (
I
)*
R
R
1 = 0.0578, wR2 = 0.1241
1 = 0.0814, wR2 = 0.1390
0.774, –0.367
,
,
e
Å–3
2
2
2 2
1/2
2
* R = Σ(F – F )/Σ(F ), ** wR = {Σ[w(Fo – Fc ) ]/Σ(Fo ) }
.
o
c
o
2
refined by fullꢀmatrix least squares on F2. Power Xꢀray
diffraction (PXRD) was recored on Bruker D8ꢀ
IR (KBr,
, cm–1): 3249, 1612, 1458, 1294, 1167,
1035, 971, 805, 761, 686, 622.
ν
ADVANCEX with Cu
K
radiation ( = 1.5418 Å).
λ
α
Xꢀray structure determination. A colorless single
Synthesis of I. The HPta was synthesized according
to the literature [13]. A mixture of ethynylbenzene
(0.102 g, 1 mmol), 2ꢀazidoacetic acid (0.121 g,
crystal of complex I was determined with MoK radiꢀ
α
ation using a BRUKER SMART APEX II CCD difꢀ
fractometer at 296(2) K using the –2 scan mode. In
the range of 2.12° ≤ θ ≤ 26.00 , a total of 35305 reflecꢀ
ω
θ
1.2 mmol) were treated with CuSO4 5H2O (0.013 mg,
⋅
°
0.05 mmol) and sodium ascorbate (0.029 g,
0.15 mmol) in MeOH (8 mL). A white solid (0.153 g,
tions were obtained with 9983 unique ones and used in
the succeeding refinements. The structure was solved
by direct methods and refined with fullꢀmatrix leastꢀ
squares on F2 using SHELXLꢀ97 [14]. The crystal data
as well as details of data collection and refinements for
the complex are listed in Table 1. The selected bond
lengths and bond angles of the title complex are listed
in Table 2.
0.76 mmol) was obtained. Its melting point is 197–
1
199°C
and chemistry shifts of H NMR (400 MHz,
DMSO) are 13.01 (s., 1H), 8.57 (s., 1H), 7.88
(m., 2H), 7.40 (s., 2H), 7.34 (s., 1H), 5.38 (s., 2H)
ppm, which are consistent with the literature reports.
A mixture of Zn(OAc)2
· 2H2O (0.066 g,
0.3 mmol), 4,4'ꢀBipy (0.021 g, 0.10 mmol), HPta
(0.040 g, 0.1 mmol), H2O (7 mL) was placed in a
23 mL Teflonꢀlined autoclave. The vessel was heated
to 120°C for 24 h, and then cooled to room temperaꢀ
ture. Colorless block crystals were obtained.
Supplementary material for structure
I has been
deposited with the Cambridge Crystallographic Data
Centre (CCDC no. 1001498; deposit@ccdc.
cam.ac.uk or http://www.ccdc.cam.ac.uk).
For C30H28N8O6Zn
RESULTS AND DISCUSSION
anal. calcd., %:
Found, %:
C, 59.11;
C, 59.04;
H, 20.68;
H, 20.89;
N, 4.46.
N, 4.54.
The ORTEP drawing of the compound with atom
labeling is shown in Fig. 1. The extended structure
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 41
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2015

SYNTHESIS, CRYSTAL STRUCTURE, AND FLUORESCENT PROPERTY
449
O(1B)
C(15)
C(14)
C(11)
C(13)
C(12)
Zn(1)
O(5B)
Zn(1A)
N(4B)
N(4)
O(5)
O(1)
O(2)
C(10) N(3)
C(8)
C(1)
C(2)
C(3)
C(4)
C(9)
C(7)
C(6) C(5)
N(2)
N(1)
Fig. 1. The labeled ORTEP molecular structure of the compound shown as 30% thermal ellipsoid probability. Symmetry codes:
(a) – 1, ; (b) 2 – , 2 –
x,
y
z
x,
–
y
z.
…
C–H
π
interaction
Hydrogen bonding
…
π π interaction
Fig. 2. The 3D structure of the complex and the interactions.
…
contains linear 1D chains formed by 4,4'ꢀBipy ligands network, a C–H
π
interaction was observed, i.e.
…
connecting Zn atoms (Zn–Zn 11.514 Å). All Zn C(12)–H(12) Cg (x, y – 1, z; Cg is the centroid of benꢀ
…
atoms are octahedrally ZnO4N2 coordinated zene C(1) C(6) atoms) with the C Cg distance of
[
]
−
through four oxygen atoms from two Pta anions and 3.696(6) Å. These adjacent 2D networks were further
…
two coordination water molecules (Zn–O 2.097(2) linked by a π π interaction between two inversionꢀ
and 2.128(2) Å, respectively) and two nitrogen atoms related triazole groups with the centroidꢀtoꢀcentroid
from two 4,4'ꢀBipy ligands (Zn–N 2.201 Å). The Zn– distance of 3.652(3) Å, resulting in the final 3D netꢀ
N bond distances are similar to those found in related work (Fig. 2).
Zn(II)ꢀ4,4'ꢀBipy coordination polymers [15].
The synthesized complex has been characterized by
PXRD at room temperature. The peak positions of the
simulated and experimental PXRD patterns are most
agreement with each other, but the phase is not absoꢀ
lutely pure and it may be caused by impurity. The differꢀ
ences in reflection intensity may be due to the preferred
orientation of the crystalline powder samples.
The abundant hydrogen bondings which plays an
important role in forming 2D structure are observed in
the layer: (a) Hꢀbonding between the water and carꢀ
… …
boxylate O atom of thePta O(5)–H(5B) O(1): O H
2.16(5) Å, OHO 144(5)°; (b) Hꢀbonding between the
coordination water and another O atoms from the carꢀ
… …
boxylate O(5)⎯H(5A) O(2): O H 1.85(4) Å, OHO
175(8)°; (c) Hꢀbonding between the C(6)–H(6) from
Table 2. Selected bond lengths (Å) and bond angles (deg)
benzene and N(1) atom of the triazole C(6)–
for
I*
…
…
H(6) N(1): N H 2.62 Å, CNO 100
°; (d) Hꢀbonding
between the C(11)–H(11) of the pydine and O atom
Bond
d
, Å
Angle
ω
, deg
…
…
of the water C(11)–H(11) O(5): O H 2.57 Å, OHO
159 ; (e) Hꢀbonding between the C(15)–H(15) of the
pydine and O atom of the Pta C(15)–H(15) O(1)
Zn(1)–O(1)
Zn(1)–O(5)
Zn(1)–N(4)
2.097(3) O(1)Zn(1)O(5) 88.46(13)
2.128(3) O(5)Zn(1)N(4) 95.60(13)
2.201(4) O(1)Zn(1)N(4) 87.62(13)
°
…
:
…
O H 2.48 Å, OHO 118 , as shown in Table 3. In the 2D
°
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 41
No. 7
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450
MA et al.
I*
Table 3. Geometric parameters of hydrogen bonds for
Distance, Å
⋅⋅⋅
D–H⋅⋅⋅
A
Angle DHA, deg
D–H
H
A
D⋅⋅⋅A
O(5)–H(5
A
)
⋅⋅⋅O(2)i
)
⋅⋅⋅O(1)ii
0.82(4)
0.80(5)
0.93
0.93
0.93
1.85(4)
2.16(5)
2.62
2.57
2.48
2.672(5)
2.850(5)
2.917(9)
3.457(6)
3.032(7)
175(8)
144(5)
100
159
118
O(5)–H(5
B
C(6)–H(6)⋅⋅⋅N(1)
C(11)–H(11
C(15)–H(15)⋅⋅⋅O(1)i
B
)
⋅⋅⋅O(5)ii
i
ii
* Symmetry codes: 2 – x, –y, 2 – z; 1 – x, –y, 2 – z.
mer displays a threeꢀdimensional layer structure,
which is associated through metal coordination,
359
…
…
π
hydrogen bonding and C–H
together with π π
interactions. The fluorescent properties of the comꢀ
plex and ligand revealed that there was a coꢀeffect of
ancillary 4,4'ꢀBipy and HPta ligand for the quenching
of fluorescence.
4
354
1
375
356
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303
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Fig. 3. The fluorescence spectra of HPta (
1
), 4,4'ꢀBipy (
2),
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Zn(OAc)
I
(
3
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the ligand and the complex in DMF at the room temꢀ
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(
λex = 218 nm) and 356 nm (λex = 238 nm), respecꢀ
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,
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tion with metal ion which change the rigidity of the
ligand. There is an increasing of the intensity of the
fluorescence when Zn(OAc)2 was added into the
ligand. However, the fluorescence quenching occurred
for this complex, which probably be assigned to charge
transfer due to the pta and 4,4'ꢀbipy mutual coordinaꢀ
tion with Zn(II).
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2015