Synthesis, structure and properties of a nickel coordination polymer with 3D supramolecular framework

Article abstract of DOI:10.1080/15533174.2016.1186069

One nickel coordination polymer with 3D supramolecular framework based on 5-(imidazol-1-ylmethyl) isophthalic acid (H₂L) as a main ligand and 1,2-bis(4-pyridyl) ethene (bpe) as a N-containing ancillary ligand, {[NiL(bpe)(H₂O)] (H₂O)₃}_n(1), has been obtained by hydrothermal synthesis and characterized by powder X-ray diffraction (PXRD), UV/vis, IR, elemental analysis, thermal gravimetric analysis (TGA) and single-crystal XRD. It crystallizes in the monoclinic, space group P2₁/c. In 1, L^2- anions connect Ni(II) ions forming 2D layers (Ni₃L₃)n and then adjacent layers are further associated together by π π interaction leading to double layers, which are formed by the neighboring imidazolyl group. Meanwhile, hydrogenbonding interactions between layers extend these double layers into 3D supramolecular network.

Full text of DOI:10.1080/15533174.2016.1186069

Inorganic and Nano-Metal Chemistry
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Synthesis, structure and properties of a nickel
coordination polymer with 3D supramolecular
framework
Fu-An Li, Wei-Chun Yang, Song-Tian Li & Xu Miao
To cite this article: Fu-An Li, Wei-Chun Yang, Song-Tian Li & Xu Miao (2017) Synthesis, structure
and properties of a nickel coordination polymer with 3D supramolecular framework, Inorganic
and Nano-Metal Chemistry, 47:3, 433-437, DOI: 10.1080/15533174.2016.1186069
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Date: 10 November 2016, At: 16:21

INORGANIC AND NANO-METAL CHEMISTRY
2017, VOL. 47, NO. 3, 433–437
http://dx.doi.org/10.1080/15533174.2016.1186069
Synthesis, structure and properties of a nickel coordination polymer with 3D
supramolecular framework
Fu-An Li, Wei-Chun Yang, Song-Tian Li, and Xu Miao
College of Chemistry and Chemical Engineering, Pingdingshan University, Pingdingshan, P. R. China
ABSTRACT
ARTICLE HISTORY
Received 1 June 2015
Accepted 1 May 2016
One nickel coordination polymer with 3D supramolecular framework based on 5-(imidazol-1-ylmethyl)
isophthalic acid (H2L) as a main ligand and 1,2-bis(4-pyridyl) ethene (bpe) as a N-containing ancillary
ligand, {[NiL(bpe)(H2O)]¢(H2O)3}n(1), has been obtained by hydrothermal synthesis and characterized by
powder X-ray diffraction (PXRD), UV/vis, IR, elemental analysis, thermal gravimetric analysis (TGA) and
single-crystal XRD. It crystallizes in the monoclinic, space group P21/c. In 1, L2¡ anions connect Ni(II) ions
forming 2D layers (Ni3L3)n and then adjacent layers are further associated together by p¢¢¢p interaction
leading to double layers, which are formed by the neighboring imidazolyl group. Meanwhile, hydrogen-
bonding interactions between layers extend these double layers into 3D supramolecular network.
KEYWORDS
Nickel; 5-(imidazol-1-
ylmethyl)isophthalic acid;
1,2-bis(4-pyridyl)ethene;
coordination polymer
Introduction
components in crystals,[15,16] the organic compounds with aro-
matic rings have the potential of building supramolecular net-
works by p¢¢¢p interactions. Taking the above into
consideration, 5-(imidazol-1-ylmethyl)isophthalic acid (H2L)
as an organic ligand is chosen for the following reasons: (1)
H2L possesses two functional groups, namely rigid carboxylate
group and flexible imidazol-1-ylmethyl group. The carboxylate
group can act not only as coordination site forming coordina-
tion polymer but also as hydrogen-bond acceptor giving rise to
supramolecular architecture. The imidazolyl can form weak
non-covalent forces based on p¢¢¢p interactions as well as pro-
vide coordination site. (2) H2L ligand with abundant functional
groups can be used as a multiconnector in the assembly of com-
plexes, and the imidazol-1-ylmethyl arm has more spatial free-
dom to adopt different orientations.[17–19] The variable
coordination modes and conformations provide the feasibility
to assemble complexes with novel structures. (3) The ligand
H2L has a very good water solubility and is very beneficial to
study its properties in hydrothermal conditions. (4) Although a
few coordination polymers based on H2L ligand have been
reported,[20,21] it is very limited to understand the coordination
chemistry of H2L.
Crystal engineering of supramolecular architectures is much
more challenging and difficult to control because of the deli-
cate nature of non-covalent forces, particularly when a great
deal of weak forces are present in a competitive environment.
A good understanding of cooperativity is therefore essential
for obtaining insights into the behavior of synthetic materials.
Crystal structures, which represent an extreme of periodic
organization of molecules in three dimensions, cannot yet be
predicted a priori, but it is interestingly becoming possible to
control molecular order to some degree by directed weak
forces assembly, for example, hydrogen bonds,[1,2] p¢¢¢p inter-
actions,[3–6] and so on. The hydrogen bond, a very important
non-covalent interaction with directionality, is a very good
tool in crystal engineering,[7,8] and the packing of molecules in
crystal structures built by conventional hydrogen bonds has
been well studied.[9–11] Unlike hydrogen bonding, p–p inter-
action is very difficult to control because of the lack of strength
and directionality,[12] so comparing with hydrogen bonds,
p–p interactions are easily omitted in construction of supra-
molecular architectures. However, the stability of supramolec-
ular networks mainly depends on cooperative weak
interactions that constitute the resultant supramolecular net-
work. Therefore, to design and construct supramolecular
framework, we not only pay attention to every non-covalent
weak forces, such as hydrogen bonds, pp interactions and so
on but also consider their cooperativity.
Inspired by the above consideration, we intend to synthesize
supramolecular architectures constructed by p¢¢¢p interaction
and hydrogen bonds. As expected, a Ni(II) 3D supramolecular
coordination polymer, {[NiL(bpe)(H2O)]¢(H2O)3}n(1), was
synthesized under hydrothermal condition, and characterized
by single-crystal X-ray diffraction analysis, elemental analyses,
powder X-ray diffraction (PXRD), thermal gravimetry (TG)
and IR.
Because aromatic rings can interact in different geometrical
arrangements, such as face-to-face and point-to-face,[13,14] and
are a very useful tool in the manipulation of molecular
CONTACT Fu-An Li
lifuanpds@126.com
College of Chemistry and Chemical Engineering, Pingdingshan University, Pingdingshan 467000, P. R. China.
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/lsrt.
CCDC 1062287 for {[Nil(BPE)(H2O)]¢(H2O)3}n(1) contains the supplementary crystallographic data for this article. These data can be obtained free of charge at
www.ccdc.cam.ac.uk/conts/retrieving.hmtl [or from the Cambridge Crystallographic Data Center, 12, Union Road, Cambridge CB21EZ, UK; fax (Internet) C44-1223/336-
033; e-mail: deposit@ccdc.cam.ac.uk].
© 2017 Taylor & Francis Group, LLC

434
F.-A. LI ET AL.
Experimental
Table 1. Crystal data and structure refinement for 1.
Compound
1
Materials and measurements
Formula
fw
Crystal system
C24H26N4O8Ni
557.20
Monoclinic
The single crystal for 1 was obtained by hydrothermal method
in Teflon-lined stainless steel container. Other starting materi-
als were of reagent grade and obtained commercially without
further purification. The FT-IR spectra were recorded from
KBr pellets in the range from 4000 to 400 cm¡1 on a Nicolet
NEXUS 470-FTIR spectrometer. Solid UV¡visible spectra
were obtained in the 200¡800 nm range on a JASCO UVI-
DEC-660 spectrophotometer. Elemental analyses for C, H and
N were performed on a Perkin-Elmer 240 elemental analyzer.
Thermal analysis was performed on an SDT 2960 thermal ana-
lyzer from room temperature to 800ꢀC with a heating rate of
10ꢀC/min under nitrogen flow. PXRD was measured at 293ꢀ K
on a Rigaku D/max-3B diffractometer (Cu-Ka, λ D 1.5418 A).
The crushed single-crystalline powder samples were prepared
by crushing the crystals and scanned from 5ꢀ to 50ꢀ with a step
of 0.1ꢀ/s.
Space group
P21/c
ꢀ
a (A)
9.9531(5)
28.9708(11)
10.7270(10)
90
122.134(4)
90
2619.3(3)
4
1.413
1160
4549
3620
0.0415
ꢀ
b (ꢀA)
c (A)
a (ꢀ)
b (ꢀ)
g (ꢀꢀ )
V (A3)
Z
Dc (g cm¡3
F(000)
)
Reflns collected
Independent reflns
R(int)
GOF on F2
1.000
0.0580
0.1449
0.993/¡0.585
R1a [I > 2s (I)]
wR2b [I > 2s (I)]
ꢀ
Max/min(eA¡3
)
ꢀ
Synthesis of H2L
graphite monochromatized MoKa radiation (λ D 0.71073 A) at
H2L was prepared by reaction of dimethyl 5-(bromomethyl)iso- room temperature using the v-scan technique. Empirical
phthalate with imidazole following the procedures used for syn- absorption corrections were applied to the intensities using the
thesis of a-imidazolyl-m-toluic acid hydrochloride.[18,19,22]
A
SADABS program.[24] The structure was solved by direct meth-
mixture of dimethyl 5-(bromomethyl)isophthalate (1.28 g, ods using SHELXS-97[25] computer program and refined by full-
5 mmol) and imidazole (1.7 g, 25 mmol) in methanol (75 mL) matrix least-squares methods on F2 with the SHELXL-97[26]
was cooled to room temperature after stirring at 80ꢀC for 24 h. program package. All non-hydrogen atoms were subjected to
The methanol was moved by evaporation to give a white solid; anisotropic refinement. The hydrogen atoms of the organic
the solid was dissolved in CH2Cl2 (»150 ml) and then washed ligands were included in the structure factor calculation at ideal-
with water. The CH2Cl2 solution was then dried over Na2CO3. ized positions using a riding model and refined isotropically.
The Na2CO3 was filtered off. Then, 200-mL water and KOH The crystallographic data and selected bond distances and
(1.12 g, 20 mmol) were added into the resulting mixture. The angles for 1 are listed in Tables 1 and 2, respectively.
reaction mixture was refluxed for 10 h, and then poured into
ice water, acidified with acetic acid to pH 3–4. After filtration,
Results and discussion
the product was obtained as pale-yellow solid (1.08 g, 88%). 1H
NMR (300 MHz, DMSO-d6, 25ꢀC): 8.39 (s, 1H); 8.03 (s, 2H);
7.86 (s, 1H); 7.26 (s, 1H); 6.96 (s, 1H); 5.37 (s, 2H). Anal. calcd
X-ray structural analysis revealed that complex 1 crystallizes in
for C12H10N2O4: C, 58.54; H, 4.09; N, 11.38%. Found: C, 58.62;
monoclinic, space group P21/c. As shown in Figure 1a, the
H, 4.28; N, 11.56%.
Crystal structure description of {[Nil(bpe)(H2O)]¢(H2O)3}n (1)
asymmetric unit for 1 consists of one Ni(II) ion, one L2¡ ion,
one bpe molecule, one coordinated water molecule and three
Synthesis of 1
free water molecules. The Ni(II) center is coordinated by three
oxygen atoms from two different L2¡ ligands (O1,O3#2,O4#2),
one coordinated water molecule, one N atom of imidazolyl
group and other N atom of bpe to achieve a distorted octahe-
dral geometry. The Ni¡N and Ni¡O bond lengths are shown
Complex 1 was synthesized hydrothermally in a Teflon-lined
stainless steel container by heating a mixture of H2L (0.0123 g,
0.05 mmol), 1,2-bis(4-pyridyl) ethene (bpe) (0.0091 g,
0.05 mmol), Ni(NO3)2¢6H2O (0.0146 g, 0.05 mmol) in 5 mL of
N,N-Dimethyl-formamide (DMF)–water (V:V D 1:1) solution
at 140ꢀC for 3 days. Green block crystal for 1 was obtained in
80% yield based on nickel. Anal. calcd for C24H26N4O8Ni
(557.20): C, 51.73; H, 4.70; N, 10.53%. Found: C, 51.67; H, 4.73;
N, 10.46%. IR (KBr pellet, cm¡1): 3439(s), 3121(m), 1609(s),
1560(s), 1363(s), 1090(m), 939(m), 748(m), 721(m), 673(w).
ꢀ
Table 2. Selected bond lengths (A) and angles (ꢀ) for complex 1.
Ni(1)-O(1)
Ni(1)-N(2)#1
2.056(3)
2.076(3)
Ni(1)-O(3)#2
Ni(1)- N(3)
2.115(3)
2.099(3)
Ni(1)-O(1w)
2.048(3)
Ni(1)-O(4)#2
2.184(3)
N(2)#1-Ni(1)-O(1)
N(2)#1-Ni(1)-O(3)#2
N(3)-Ni(1)-O(1)
N(3)-Ni(1)-O(3)#2
O(1)-Ni(1)-O(1w)
O(3)#2-Ni(1)-O(4)#2
O(1)-Ni(1)-O(3)#2
N(3)-Ni(1)-N(2)#1
94.77(13)
89.62(13)
88.77(13)
88.32(13)
97.19(12)
61.49(11)
158.39(12)
175.09(14)
N(2)#1-Ni(1)-O(1w)
N(2)#1-Ni(1)-O(4)#2
N(3)-Ni(1)-O(1w)
N(3)-Ni(1)-O(4)#2
O(1w)-Ni(1)-O(3)#2
O(4)#2-Ni(1)-O(1)
O(1w)-Ni(1)-O(4)#2
89.78(13)
95.02(12)
86.40(13)
87.87(12)
103.99(12)
97.00(11)
164.56(12)
Crystallographic data collection and structure
determination
Single-crystal X-ray diffraction data of 1 were collected on a
Bruker Smart Apex CCD diffractometer
[23]
Symmetry codes: #1: ¡1 C x, y, z; #2: ¡1 C x, y, ¡1 C z.
equipped with

INORGANIC AND NANO-METAL CHEMISTRY
435
Figure 1. (a) Metal coordination and atom labeling in 1 (thermal ellipsoids at 50% probability level). All hydrogen atoms are omitted for clarity. (b) The 2D layer structure.
(c and d) The double layer structure of complex 1. (e) The hydrogen bonding interactions of 1. Symmetry codes: #1: ¡1 C x, y, z; #2: ¡1 C x, y, z; #3: ¡1 C x, 1.5¡y, 0.5
C z; #4: ¡x, 2¡y, 1¡z; #5: x, y, 1 C z; #6 ¡x, 2¡y, ¡z; #7: x, y, ¡1 C z.
in Table 2. L2¡ links three Ni atoms in bridging mode, and Ni atmosphere in the range of 30–800ꢀC (Figure 3). The TG curve
(II) center coordinates to three different L2¡ ligands giving a for 1 shows the initial weight loss in the temperature range of
2D layer in the ac plane (Figure 1b). Then adjacent layers are 30¡100ꢀC, which can be ascribed to the removal of lattice
associated together by weak p¢¢¢p interactions (centroid¡cent- water molecules (observed: 10.01% and calculated: 9.70%).
ꢀ
roid distance, 3.7573(1) A) between the neighboring imidazolyl Then, a gradual weight loss from 100ꢀC to 210ꢀC is attributed
rings leading to double layers (Figure 1c and d), and these dou- to the release of one coordinated water molecule (observed,
ble layers are further connected by the inter-layer hydrogen 3.01%; calculated, 3.23%), and there is a steep weight loss
bonds (Figure 1e) constructing 3D supramolecular architecture. between 338ꢀC and 429ꢀC, which could be assigned to the
It is well known that the stability for supramolecular frame- decomposition of the framework (Figure 3).
works depend on cooperative weak interactions, which constitute
the resultant supramolecular architecture. In crystal structure of
Electronic spectra of complex 1
1, three sorts of hydrogen-bonding interactions and one p¢¢¢p
interaction have been observed, which further stabilize 3D supra-
The diffuse-reflectance UV–vis spectra reveal the absorption
features of complex 1 and ligand H2L (Figure 4), and the two
molecular networks of complex 1 (Figure 1c–e, Table 3).
spectra consist of absorption components in the UV and Vis
regions. In the two cases, the intense absorption peaks at 235
and 237 nm for complex 1 and ligand H2L can be ascribed to
Powder XRD studies of 1
To check the purity, PXRD for complex 1 has been studied. As
shown in Figure 2, all the peaks displayed in the experimental pat-
terns correspond well with those in the simulated patterns gener-
ꢀ
Table 3. Hydrogen-bond geometry (A,ꢀ).
ated by single-crystal diffraction data, indicating the high purity
DꢁꢁH¢¢¢A
DꢁꢁH
H¢¢¢A
D¢¢¢A
DꢁꢁH¢¢¢A
of the synthesized samples. The difference in reflection intensities
between the simulated and experimental patterns was due to the
variation in preferred orientation of the synthesized powder sam-
ples during the collection of the observed PXRD data.
O(1W)-H(1WB)¢¢¢N(2)#3
O(1W)-H(1WA)¢¢¢O(2)
O(2W)-H(2WA)¢¢¢O(2)#7
O(2W)-H(2WB)¢¢¢O(3w)
O(3W)-H(3WB)¢¢¢O(3w)#6
O(3W)-H(3WB)¢¢¢O(4w)
O(4W)-H(4WA)¢¢¢O(4)
O(4W)-H(4WB)¢¢¢O(1)#4
0.850
0.850
0.850
0.850
0.850
0.850
0.850
0.920
1.88
1.83
2.09
1.68
2.30
1.99
2.07
1.95
2.716 (5)
2.637 (5)
2.937 (18)
2.535 (18)
2.738 (19)
2.837 (11)
2.854 (4)
2.869 (5)
168.0
156.8
178.9
179.0
112.0
178.5
152.6
172.5
Thermal stability of 1
To characterize this complex in terms of thermal stability, TG
analyses for complex 1 have been conducted under a nitrogen
Symmetry codes: #3: ¡1 C x, 1.5-y, 0.5 C z; #4: ¡x, 2¡y, 1¡z; #6: ¡x, 2-y, ¡z; #7:
x, y, ¡1 C z.

436
F.-A. LI ET AL.
Ni(II) (d8) ion in distorted octahedral coordination
configuration.
Funding
This research was supported by the Education Chamber of Henan Prov-
ince (No.15A150068) and the Key Laboratory of Applied Chemistry of
Pingdingshan University (No.201201).
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