Hydrogen bonded supra-molecular framework in inorganic-organic hybrid compounds of Mn(II) and Zn(II): Syntheses, structures, and photoluminescent studies

Article abstract of DOI:10.1016/j.molstruc.2013.11.026

In our efforts to tune the structures of compounds by selection of polycarboxylic acid ligands and N-heterocyclic ligands, two novel unreported compounds [Mn(cipt)(m-BDC)·H₂O]_n (1) and [Zn(mip)(NDC)]_n (2) were obtained by

Full text of DOI:10.1016/j.molstruc.2013.11.026

Journal of Molecular Structure 1058 (2014) 277–283
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Hydrogen bonded supra-molecular framework in inorganic–organic
hybrid compounds of Mn(II) and Zn(II): Syntheses, structures,
and photoluminescent studies
a
b
Li Yan a, , Chuanbi Li , Xiaoli Chen
⇑
a College of Chemistry, Jilin Normal University, Siping 136000, PR China
b Songyuan City Qianguo’erluosi County Second Senior High School, Songyuan 138000, PR China
g r a p h i c a l a b s t r a c t
h i g h l i g h t s
The reaction of Mn(SO4)2ÁH2O, ZnCl2 with N-heterocyclic ligands and poly-carboxylate ligands yielded
two novel coordination polymers. All compounds were characterized by elemental analysis, FT-IR, ther-
mogravimetric analysis and X-ray crystallography. Furthermore, we studied the solid-state and solvent
fluorescence spectrum, as well as the ligands.
ꢀ
ꢀ
Two compounds have been
synthesized and characterized.
Weak interactions provide additional
assembly forces. The fluorescence
spectrum of the complexes are
investigated.
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 12 August 2013
Received in revised form 7 November 2013
Accepted 8 November 2013
Available online 16 November 2013
In our efforts to tune the structures of compounds by selection of polycarboxylic acid ligands and N-het-
erocyclic ligands, two novel unreported compounds [Mn(cipt)(m-BDC)ÁH2O]n (1) and [Zn(mip)(NDC)]n (2)
were obtained by hydrothermal reaction, where cipt = 2-(3-chlorophenyl)-1H-imidazo[4,5-f][1,10]phe-
nanthroline, m-BDC = isophthalic acid, mip = 2-(3-methoxyphenyl)-1H-imidazo[4,5-f][1,10]phenanthro-
line, and NDC = naphthalene-1,4-dicarboxylic acid. All compounds have been characterized by IR,
elemental analyses, single crystal X-ray diffraction, and thermogravimetric analysis (TGA). Structural
analyses show that compounds 1 and 2 possess mononuclear structures and exhibit 1D zigzag chain
structure. The intermolecular O–HÁ Á ÁO and N–HÁ Á ÁO interactions extend the compounds into 2D sheet
Keywords:
Coordination compounds
Crystal structures
Hydrothermal synthesis
Fluorescence properties
networks. There are H-bonds and
fluorescence spectrum of compounds 1 and 2 were also investigated.
Ó 2013 Elsevier B.V. All rights reserved.
p–p interactions in the title compounds. Furthermore, the solid-state
1. Introduction
Recently, the rational design and synthesis of new polymeric
transition metal–organic frameworks (MOFs) have received
intense interest and attentions for their potential applications as
⇑
Corresponding author. Tel.: +86 15844401591.
E-mail address: yanli820618@163.com (L. Yan).
0022-2860/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.molstruc.2013.11.026

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L. Yan et al. / Journal of Molecular Structure 1058 (2014) 277–283
function materials as well as their structural diversity and intrigu-
ing variety of topologies [1–6]. These MOFs can be specially de-
signed by the careful selection of metal centers with preferred
coordination geometries. Selection of appropriate multidentate li-
gands to coordinate metal ions is a key strategy for construction.
The selection of polycarboxylate anions is extremely important be-
cause changing the structures of the anions can control and adjust
the structures of coordination polymers. Among poly-carboxylates,
the best studied are dicarboxylates, tricarboxylates, and
biphenyldicarboxylates. 2-(Pyridin-2-yl)pyridine, 4-(pyridin-4-
yl)pyridine, and 1,10-phenanthroline can act as terminal ligands
and provide supramolecular interaction sites for molecular recog-
nition [7–10]. So far, 1,10-phenanthroline (phen) has been widely
used to build supra-molecular architectures for its excellent coor-
dinating ability and large-conjugated system. However, far less
attention has been given to their derivatives. In this paper, two
important phen derivative possesses fruitful aromatic systems
cooled to room temperature at a rate of 5 °C/h. Compound 2 were
collected in 76% yield based on Zn. C32H20N4O5Zn: calcd. C 63.43%
H 3.33%, N 9.25%; found: C 63.52%, H 3.36%, N 9.41%.
The synthesis parameters play an important role in the forma-
tion of fascinating new compounds. However, a detailed under-
standing of the role that these variables play in the synthesis of
hybrid inorganic–organic systems is, to date, a challenging work
in this field. The differences in the synthetic condition in 1 and 2
are the pH value and temperature of the reactions. We found that
higher pH value and temperature will favor the coordination poly-
mer 2 produced, and it is clear that the pH value and temperature
of the reaction play an important role in controlling the structures
of MOFs.
2.3. X-ray crystallography
Single-crystal X-ray diffraction data for compounds 1 and 2
were collected at 293(2) K with a Bruker SMART APEX II CCD dif-
have
been
prepared:
2-(3-chlorophenyl)-1H-imidazo[4,5-
f][1,10]phenanthroline (cipt) and 2-(3-methoxyphenyl)-1H-imi-
dazo[4,5-f][1,10]phenanthroline (mip) in view of their following
characteristics: (1) they possess extended aromatic system, which
fractometer equipped with a graphite-monochromatized Mo K
a
radiation (k = 0.71073 A) in the range of 1.72 6 h 6 26.06° for 1
and 2.10 6 h 6 26.09° for 2. Absorption corrections were applied
using multi-scan technique and all the structures were solved by
direct methods and refined by full-matrix least-squares based on
F2 using the programs SHELXS-97 [14] and SHELXL-97 [15]. Non-
hydrogen atoms were refined with anisotropic temperature
parameters and all hydrogen atoms were refined isotropically.
Experimental details for crystallographic data and structure refine-
ment parameters for compounds 1 and 2 are listed in Table 1.
potentially provide supramolecular interactions such as p–p inter-
actions between the aryl rings to construct intriguing structures;
(2) they have strong coordination with two nitrogen atoms; (3)
they possess rigidity of coordination to metal atoms. Nowadays
the interest in Zn(II) compounds comes from their diverse applica-
tions especially in photochemistry due to their luminescent prop-
erties [11,12]. In this paper, we synthesized two polymers
containing Mn2+ and Zn2+ ions and reported the syntheses, crystal
structures, thermogravimetric analysis (TGA), as well as photolu-
minescence properties of coordination polymers 1–2.
3. Results and discussion
3.1. Structural analysis of compound 1
2. Experimental section
The molecular structure is shown in Fig. 1. The 1D zigzag chain
structure is suggested in Fig. 2, and 2D sheet structure is shown in
Fig. 3. Selected bond lengths and bond angles are given in Table 2.
Single-crystal X-ray structural analysis reveals that the asymmetric
2.1. Materials and physical measurements
The ligands cipt and mip were prepared according to the
description in the literature procedures [13]. All the other chemi-
cals from commercial sources were commercially available, and
used without further purification. The FT-IR spectrum was mea-
sured with KBr pellets in the range of 4000–400 cmÀ1 on a Per-
Table 1
Crystal data and details of structure refinement parameters for 1 and 2.
kin–Elmer 240C spectrometer. TGA was performed using
a
Perkin–Elmer TG-7 analyzer at the rate of 10 °C/min rise of
temperature in nitrogen atmosphere. Crystal structures were
determined on a Bruker SMART APEX II CCD X-ray diffractometer.
Carbon, hydrogen and nitrogen elemental analyses were per-
formed with a PE-2400 elemental analyzer. Fluorescence spectra
were recorded on a FLSP 920 Edinburgh fluorescence spectrometer.
Compound
1
C
2
Empirical formula
Formula weight
Crystal system
space group
a (nm)
54H32Cl2Mn2N8O10
C32H20N4O5Zn
605.89
monoclinic
p2(1)/n
1.27411(8)
1.49255(9)
1.35881(8)
90.989(1)
2.5836(3)
4
1133.66
monoclinic
C2/c
1.4124(6)
2.3311(1)
1.5703(1)
102.655(6)
5.045(5)
4
b (nm)
c (nm)
b (°)
2.2. Syntheses
Volume (nm3)
Z
Density (Mg/m3)
(calculated)
Absorption coefficient
1.493
1.558
[Mn(cipt)(m-BDC)ÁH2O]n (1):
A mixture of cipt (0.100 g,
0.3 mmol), Mn(SO4)2ÁH2O (0.051 g, 0.3 mmol), isophthalic acid
(m-BDC) (0.100 g, 0.6 mmol) in distilled H2O (18 mL) was stirred
at room temperature and adjusted the pH value to 6.0 with NaOH.
The cloudy solution were put into a 30-mL Teflon-lined stainless
vessel at 170 °C for 3 days and afterwards cooled to room temper-
ature at a rate of 5 °C/h. The yellow crystals of compound 1 were
obtained in 81% yield based on Mn.C54H31Cl2Mn2N8O10: calcd. C
57.26%, H 2.75%, N 9.89%; found: C 57.35%, H 2.89%, N 9.81%.
[Zn(mip)(NDC)]n (2): Compound 2 was synthesized by a proce-
dure similar to that used for 1 except for some syntheses condition.
The mixture of mip, ZnCl2, and NDC was adjusted the pH value to
8.5 with NaOH, and the cloudy solution were put into a 30-mL Tef-
lon-lined stainless vessel at 180 °C for 3 days and afterwards
0.675
2304
1.003
1240
(mmÀ1
)
F(000)
Crystal size (mm3)
Theta range (°)
0.318 Â 0.115 Â 0.091 0.272 Â 0.177 Â 0.160
1.7226.06
13808
2.1026.09
14000
5107 [0.0502]
1.002
R1 = 0.0456
wR2 = 0.1001
R1 = 0.0855
wR2 = 0.814
3.487, À0.291
Reflections collected
Unique reflections [Rint
Goodness-of-fit on F2
]
4976 [0.0608]
0.983
R1 = 0.0707
wR2 = 0.1827
R1 = 0.1191
wR2 = 0.2134
Final R indices [I > 2
r
(I)]
R indices (all data)
Largest difference peak and 2.202, À0.545
hole (e. ÅÀ3
)

L. Yan et al. / Journal of Molecular Structure 1058 (2014) 277–283
279
coordinated water molecule, and two nitrogen atoms donors
[Mn–N = 2.265(4)–2.272(4) Å] from one chelating cipt ligand,
forming a distorted octahedral geometry. The angle of O(2)–
Mn(1)–O(1), O(1)–Mn(1)–N(1), N(1)–Mn(1)–O(1W) and O(2)–
Mn(1)–O(1W) is 56.84°, 100.34°, 113.34° and 90.95°, and the
sum is 361.47°. For the coordination environment of Mn(1), the
Mn1, O(1W), O(1), N(1), O(2) atoms define the basal plane, and
the N(2) and O(3) atoms occupy the apical axial positions. The
equation of
a plane is 10.1820(0.0141)x + 2.9168(0.0293)y +
7.9639(0.0175)z = 4.0545(0.0068). The deviation of atoms Mn1,
O(1W), O(1), N(1), O(2), N(2) and O(3) to the plane is À0.1226,
À0.1282, À0.2429, 0.1913, 0.3024, 2.1083 and À2.1488 Å, respec-
tively. The distances of Mn–O/N bond lengths are all consistent
with corresponding bond lengths found in the literature [20–25].
The m-BDC acid bridges two adjacent Mn centers to form a 1D zig-
zag chain structure in two different coordination modes: one m-
BDC acid bridges two adjacent Mn centers in mono-bridging
coordination mode with distance of MnÁ Á ÁMn is 11.0335 Å, and
one m-BDC acid bridges two adjacent Mn centers in bidentate che-
lating coordination mode with distance of MnÁ Á ÁMn is 9.4487 Å
(Fig. 2). Two different m-BDC ligands arranged almost perpendicu-
lar to each other while coordinating to metal center. Hydrogen
bonding interactions are usually important in the synthesis of
supramolecular architectures. There are three types of H-bonds
interactions in compound 1: O–HÁ Á ÁO, N–HÁ Á ÁO and C–HÁ Á ÁO inter-
actions. The most interesting aspect of the structure in 1 concerns
Fig. 1. The molecular structure of compound 1 (hydrogen atoms were omitted).
unit of compound 1 crystallizes in monoclinic, space group C2/c.
Each Mn atom is coordinated by one m-BDC acid, one cipt mole-
cule, and one water molecule (Fig. 1). Mn(II) metal exhibits pen-
ta-, six-, or seven-coordinated mode [16–19]. The Mn(II) atom in
compound 1 shows a hexa-coordinated arrangement, which arises
from three oxygen atoms [Mn–Ocarboxylic = 2.082(4)–2.348(4) Å,
Mn–Owater = 2.135(4) Å] from two distinct m-BDC ligands, one
the
intermolecular
O–HÁ Á ÁO
[H(1 WA)Á Á ÁO(4) = 1.800 Å,
Fig. 2. 1D zigzag chain structure of compound 1 (hydrogen atoms were omitted).
Fig. 3. 2D layer structure of compound 1 linked by O–HÁ Á ÁO hydrogen bonds (dotted lines represent hydrogen bonds).

280
L. Yan et al. / Journal of Molecular Structure 1058 (2014) 277–283
Table 2
consists of one Zn(II) atom, one mip ligand, and one NDC ligand.
Zn(II) metal exhibits four-, penta-, six- mode [26–29]. The Zn(II)
atom is four-coordinated with two nitrogen atoms (N(1), N(2))
from one chelating mip ligand and two oxygen atoms (O(2),
O(4)) from two different monodentate bridging NDC ligands, form-
ing a distorted trigonal pyramidal geometry. The N(O)–Zn–O(N)
angles range are from 113.12(10)° to 123.08(11)°. The bond dis-
tances of Zn–O in compound 2 are from 1.958(3) to 1.987(2) Å,
and those of Zn–N bond distances fall in the 2.070(3) to
2.071(3) Å range, which are similar with the values reported [30–
32,11,33]. The average bond of Zn–O is 1.973 Å, smaller than the
average bonds of Zn–N (2.071 Å). Each Zn(II) atom is linked to an-
other two Zn(II) atoms by bis-bridging NDC ligands, and this lead
to the formation of a 1D zigzag chain network with the distances
of ZnÁ Á ÁZn are 10.6168 Å (Fig. 5). The N-heterocyclic ligands mip
are attached to both sides of this zigzag chain regularly, and mip
ligands on the same sides are parallel with the angular separation
of the zigzag chain are 89.323°. The most interesting aspect of the
Selected bond lengths [Å] and bond angles [°] for compound 1.
Bond
Dist.
Bond
Dist.
Mn(1)–O(1)
Mn(1)–O(3)
Mn(1)–N(1)
2.263(4)
2.082(4)
2.272(4)
Mn(1)–O(2)
Mn(1)–O(1W)
Mn(1)–N(2)
2.348(4)
2.135(4)
2.265(4)
Angle
(°)
Angle
(°)
O(3)–Mn(1)–O(1)
O(1W)–Mn(1)–O(1)
O(1W)–Mn(1)–O(2)
O(3)–Mn(1)–N(2)
O(1)–Mn(1)–N(2)
O(1W)–Mn(1)–N(1)
N(2)–Mn(1)–O(2)
N(2)–Mn(1)–N(1)
91.38(17)
146.27(13)
90.95(13)
156.73(16)
97.70(15)
113.34(14)
89.51(14)
72.57(14)
O(3)–Mn(1)–O(1W)
O(1)–Mn(1)–O(2)
O(3)–Mn(1)–O(2)
O(1W)–Mn(1)–N(2)
O(3)–Mn(1)–N(1)
O(1)–Mn(1)–N(1)
N(1)–Mn(1)–O(2)
93.14(16)
56.84(12)
113.27(15)
91.10(15)
84.76(15)
100.34(14)
149.47(14)
structure in
[H(3A)Á Á ÁO(2) = 2.090 Å,
H(3A)Á Á ÁO(2) = 167°] interactions, which help in the construction
of the 2D layer structure (Fig. 6). Moreover, there are interac-
2
concerns the intermolecular N–HÁ Á ÁO
N(3)Á Á ÁO(2) = 2.934 Å and N(3)–
p–p
tions between the aryl ring of mip ligands in coordination polymer
2 with distance of cg(1) cg(2) ring centroid is 3.619 Å. Cg(1): C14–
C15–C16–C17–C18–C19, Cg(2): C4–C5–C6–C7–C11–C12.
Dicarboxylates are widely used in the assembly of supra-molec-
ular architectures because of their diverse coordination modes and
bridging ability. For example, the BDC ligand can function in che-
lating bis-bidentate, bis-monodentate, mono-bidentate, bridging
bis-bidentate, monodentate–bidentate or chelating/bridging bis-
bidentate modes [26]. In the title compounds, we can see the final
structures are always decided by the diversity of coordination
modes of dicarboxylates ligands, and coordination modes (chelat-
ing bis-bidentate or bis-monodentate) usually raise the 1D chain
or 1D double-chain structure.
Fig. 4. The molecular structure of compound 2 (hydrogen atoms were omitted).
O(1W)Á Á ÁO(4) = 2.615 Å and O(1W)–H(1WA)Á Á ÁO(4) = 140°] inter-
actions, which help in the construction of the 2D layer structure
(Fig. 3). Moreover, there are p–p interactions between the aryl ring
of cipt ligands in coordination polymer 1 with distance of cg(1)
cg(2) ring centroid is 3.614 Å. Cg(1): C1–C2–C3–C4–C11–N1,
Cg(2): C4–C5–C6–C7–C11–C12.
3.3. IR spectra
The FT-IR spectra absorption peaks at 3214 cmÀ1 for 1, and
3132, 3206 cmÀ1 for 2 correspond to the C–H stretching mode
for the aromatic rings. The infrared spectrum of the compound 1
exhibited absorption at 3466 cmÀ1, which is assigned to O–H
stretching vibration of the water molecules. It is a clear indication
of the presence of water molecules. There are two peaks at 1625
and 1554 cmÀ1, which correspond to the antisymmetric stretching
of carboxyl, and the absorption of 1398 cmÀ1 corresponds to the
3.2. Structural analysis of compound 2
The molecular structure is shown in Fig. 4, and the 1D zigzag
chain structure is shown in Fig. 5. The 2D layer structure is shown
in Fig. 6. Selected bond lengths and bond angles are listed in
Table 3. As shown in Fig. 4, the asymmetric unit of compound 2
Fig. 5. The 1D zigzag chain of compound 2 (hydrogen atoms were omitted).

L. Yan et al. / Journal of Molecular Structure 1058 (2014) 277–283
281
Fig. 6. The 2D layer structure of compound 2 by N–HÁ Á ÁO hydrogen bonds (dotted lines represent hydrogen bonds).
Table 3
Selected bond lengths [Å] and bond angles [°] for compound 2.
Bond
Dist.
Bond
Dist.
Zn(1)–O(2)
Zn(1)–N(1)
1.987(2)
2.070(3)
Zn(1)–O(4)
Zn(1)–N(2)
1.958(3)
2.071(3)
Angle
(°)
Angle
(°)
O(4)–Zn(1)–O(2)
O(2)–Zn(1)–N(1)
O(2)–Zn(1)–N(2)
109.18(11)
113.12(10)
123.08(11)
O(4)–Zn(1)–N(1)
O(4)–Zn(1)–N(2)
N(1)–Zn(1)–N(2)
119.81(12)
109.41(11)
80.45(10)
symmetric stretching of carboxyl. The
D
v (vas(COOÀ)–vs(COOÀ))
are 227 and 156 cmÀ1, indicates that the carboxyls are monoden-
tately and bidentately coordinated with Mn(II) atoms. In 2, the
strong characteristic absorption peak at 1662 cmÀ1 is attributed
to the antisymmetric stretching vibration of the coordinated
carboxyl groups, and the peak at 1397 cmÀ1 corresponds to the
symmetric stretching of carboxyl. The separation is 265 cmÀ1
,
Fig. 7. TGA curves of compounds 1 and 2.
which indicates that the carboxyls groups adopt monodentate
coordination modes. The IR results are good agreement with their
solid structural features from the results of their crystal structures.
bonds and
p–p interactions reinforce the structural thermal stabil-
ity for MOFs.
3.4. Thermal properties
3.5. Photoluminescent properties
To examine the thermal stability of compounds 1 and 2, TG
curves have been obtained from crystalline samples in the flowing
nitrogen atmosphere at a heating rate of 10 °C/min (Fig. 7). In com-
pound 1, First weight loss of 3.11% from 262 to 267 °C reveals the
loss of the water molecule (calcd. 3.17%). The second weight loss of
27.50% from 267 to 501 °C corresponds to the loss of m-BDC li-
gands (calcd. 29.29%), and the last weight loss of 59.10% from
501 to 670 °C reveals the loss of the cipt ligands (calcd. 58.35%).
Compound 2 exhibits good thermal stability and can stable before
the temperature of 361 °C, and the first weight loss of 32.13% from
361 to 397 °C corresponds to the loss of NDC ligands (calcd.
35.68%). The last weight loss of 52.87% in the temperature range
of 397–598 °C can be ascribed to the release of mip ligands (calcd.
53.86%). Compared with the similar compounds without H-bonds
Luminescence property is very important in photochemistry
and photophysics. So in this study, we research the luminescence
of compounds 1 and 2, as well as the free ligands cipt and mip
(Figs. 8 and 9). The free ligands exhibit emissions at 539 nm (exci-
tation at 347 nm) for cipt, and at 541 nm for mip (excitation at
320 nm). Compound 1 shows one broad emission band with the
maximum intensity at 612 nm upon excitation at 330 nm, which
is red-shifted by 73 nm relative to the emission wavelength of free
ligand cipt. Compound 2 shows one broad strong emission band
with the maximum intensity at 619 nm upon excitation at
340 nm, which is red-shifted by 78 nm relative to the emission
wavelength of free ligand mip. The energy of the luminescence
suggests that the most possible assignment for the emissions of
1 originates from ligand-to-metal charge transfer (LMCT), and the
emissions of 2 mainly originate from the intra-ligand fluorescent
or
p–p interactions [34–36,18], our compounds shows good ther-
mal stability, and it is noteworthy that the existence of hydrogen

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L. Yan et al. / Journal of Molecular Structure 1058 (2014) 277–283
emissions of ligands [37]. In order to explore the potential of com-
pound 2 in terms of sensing small molecules, its luminescent prop-
erties in different solvent emulsions were investigated. The 2-
solvent emulsions were prepared by introducing powder of 2 into
4 mL methanol, ethanol, and N, N-dimethylformamide (DMF),
respectively. As shown in Fig. 10, the luminescent intensity of 2
is largely dependent on the solvent molecules, which exhibits dif-
ferent degrees of quenching effects in the solvents. Compounds 1
and 2 exhibit strong emissions, the reason may be attributed to
the rigidity of N-heterocyclic ligands. The rigidity is favor of energy
transfer and reduces the loss of energy through a radiationless
pathway. The coordination polymers 1 and 2 may be good candi-
date for potential photoluminescence material because it is highly
thermally stable and insoluble in water and common organic
solvents.
4. Conclusions
In summary, we have reported two compounds formed by poly-
carboxylate and N-heterocyclic ligands. The polycarboxylates
ligands function in mono-bridging and bidentate-chelating coordi-
nation modes to form 1D zigzag chain structure in compound 1,
and function in bis-bridging coordination modes to form a 1D zig-
zag chain network in compound 2. It is noteworthy that non-cova-
Fig. 8. Luminescent spectrum of ligand cipt and compound 1 in solid state at room
temperature.
lent interactions (
p p interactions, H-bond and coordination
Á Á Á
bonds) can be one of the most powerful force for instructing and
directing the supra-molecular architectures. The results also pres-
ent a feasible strategy for the construction of framework architec-
tures by synthesis condition design, such as pH value, temperature,
and so on. This material will give new impetus to the construction
of novel functional material with potentially useful physical prop-
erties. Further studies are now under way in our laboratory.
Supplementary material
CCDC 912838 and 910139 contain the supplementary crystallo-
graphic data for 1 and 2, respectively. These data can be obtained
free of charge from the Cambridge Crystallographic Data Centre
via www.ccdc.cam.ac.uk/data request.cif.
Acknowledgments
Fig. 9. Luminescent spectrum of ligand mip and compound 2 in solid state at room
temperature.
We thank Jilin Normal University, and the Science Development
Project of Jilin Province of China (20130522071JH) for financial
support.
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