Crystal structure, thermal behavior, luminescence and theoretical calculation of a new Pb(II) coordination complex

Article abstract of DOI:10.1016/j.molstruc.2020.128950

In this report, a new coordination complex Pb(CDIPT)₂(L)₂ (CDIPT= 10?chloro?2-(2,4-dichlorophenyl)-1H-imidazo[4,5-f]-[1,10]phenanthroline, HL= 2,4-dichlorophenyl acrylic acid) has been synthesized and fully characterized by elemental analysis, IR spectroscopy, UV spectrum, single-crystal X-ray diffraction analysis, luminescence spectra, TGA and powder X-ray diffraction. The structural analysis showed that the complex 1 is a zero dimensional structure with seven coordinated Pb(II) ion. And further, the adjacent complex units are extended into a 2D supramolecular network through the H-bonds [N(4)-H(4)???O(4) and N(7)-H(7)???O(1)]. The luminescence explorations demonstrated that complex 1 has good optical properties. In addition, the quantum chemistry calculations were performed with the Gaussian09 program.

Full text of DOI:10.1016/j.molstruc.2020.128950

Journal Pre-proof
Crystal structure, thermal behavior, luminescence and theoretical
calculation of a new Pb(II) coordination complex
He Wang , Shuang Han , Linan Dun , Baosheng Zhang ,
Xue Chen , Jiajun Wang , Chuanbi Li , Chunling Liu
PII:
S0022-2860(20)31275-8
DOI:
Reference:
https://doi.org/10.1016/j.molstruc.2020.128950
MOLSTR 128950
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Journal of Molecular Structure
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Revised date:
Accepted date:
12 March 2020
16 July 2020
20 July 2020
Please cite this article as: He Wang , Shuang Han , Linan Dun , Baosheng Zhang , Xue Chen ,
Jiajun Wang , Chuanbi Li , Chunling Liu , Crystal structure, thermal behavior, luminescence and the-
oretical calculation of a new Pb(II) coordination complex, Journal of Molecular Structure (2020), doi:
https://doi.org/10.1016/j.molstruc.2020.128950
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Highlights
• One new Pb(II) complex has been synthesized with DIPT and HL.
• The complex 1 has been characterized by IR and single crystal X-ray diffraction.
• The PXRD, TGA, UV and Luminescent property were also investigated.
• The calculated absorption value is in closed the experimental result.
• Intermolecular hydrogen bonding give rise to 2D supramolecular arrangements.

Crystal structure, thermal behavior, luminescence and theoretical
calculation of a new Pb(II) coordination complex
He Wang a,b , Shuang Han a,b , Linan Dun a,b, Baosheng Zhang a,b, Xue Chen a,b , Jiajun
Wang a,b, Chuanbi Li a, b,c, Chunling Liu a,b,c٭
a
Department of Chemistry, Jilin Normal University, Siping 136000, PR China
b
Key Laboratory of Preparation and Application of Environmental Friendly Materials, Ministry of Education, Jilin
Normal University, Changchun 130103, China
c
College of Jilin Province, Engineering Research Center of Medicine Intermediate, Siping, Jilin 136000, China
Abstract: In this report,
a
new coordination complex Pb(CDIPT)2(L)2 (CDIPT=
10-chloro-2-(2,4-dichlorophenyl)-1H-imidazo[4,5-f]-[1,10]phenanthroline, HL= 2,4-dichlorophenyl
acrylic acid) has been synthesized and fully characterized by elemental analysis, IR spectroscopy, UV
spectrum, single-crystal X-ray diffraction analysis, luminescence spectra, TGA and powder X-ray
diffraction. The structural analysis showed that the complex 1 is a zero dimensional structure with
seven coordinated Pb(II) ion. And further, the adjacent complex units are extended into a 2D
supramolecular network through the H-bonds [ N(4)-H(4)···O(4) and N(7)-H(7)···O(1) ]. The
luminescence explorations demonstrated that complex 1 has good optical properties. In addition, the
quantum chemistry calculations were performed with the Gaussian09 program.
Keywords: Crystal structure; Pb(II) complex; Luminescence; Quantum chemistry calculations
1. Introduction
Coordination complexes are crystal materials with periodic network formed by self-assembly of
metal ions or metal clusters and organic ligands. Coordination complexes have become a hot topic in
the field of new materials due to their adjustable structures, high crystallinity and controllable porosity.
[1-6]. Coordination complexes can be divided into one-dimensional chain structure, two-dimensional
layer structure and three-dimensional network [7-9]. And now, it is easy to acquire the different
coordination complexes with desired structures and properties. There are lots of methods to synthesize
the coordination complexes such as evaporative solvent method, diffusion method, hydrothermal or
solvent-thermal method, ultrasonic and microwave method etc. [10-12].
٭ Corresponding author. Tel.: +86 13844402157.
E-mail address: liu_chunling@126.com (C. Liu).

The center metal ions and organic ligands show the decisive role for the structures and functions
of targeted coordination complexes [13-15]. The selection of metal centers of coordination complexes
almost covers all metals, including main group elements, transition elements, lanthanide metals, etc.
[16-22]. The different valence states and coordination capacities of different metal ions can also affect
the structures and properties of materials. For organic ligand’s selection, the transition from the
earliest easily collapsed nitrogen heterocyclic ligands to the stable carboxylic acid ligands [23]. In
order to solve the collapse of coordination complexes which were removing guest molecules, chemists
began to synthesized coordination complexes with one or more functional groups based on anion and
neutral ligands. The combination of different functional groups greatly expanded the application scope
of coordination complexes [24]. Due to large specific surface area, adjustable channel, easy
functionalization and interesting topological structure, researchers have made great advances in fields
such as molecular magnetics, photoluminescence, ion exchange, gas storage, and catalysis.[25-34].
Heterocyclic compounds play an important role in coordination chemistry [35-39].
1,10-phenanthroline and its derivatives [39] have been widely studied on account of their unique
structures and properties. Each 1,10-phenanthroline molecule is composed of three aromatic rings,
which has strong conjugation and is easy to coordinate with a variety of metal ions to produce
complexes with unique functions. Because it has a good conjugated system, which can increase the
thermal stability and fluorescence intensity of coordination complexes [41-43]. Therefore, it has
widespread applications in optical, magnetic and fluorescent materials.
β-substituted phenylacrylic acid has good coordination ability and thermal stability. For example,
S. Han, etc. [44] investigated the synthesis, crystal structure and theoretical calculation of triphenyltin
(IV) polymer based on 2,4-dichlorophenylacrylic acid. H. Y. Sun, etc. [45] successfully synthesized a
novel Co(II) by using 2-(2,4-dichlorophenyl)-1H-imidazo[4,5-f]-[1,10]phenanthroline as the
N-heterocyclic ligand and the 3-(2-chlorophenyl)acrylic acid. Therefore, it is meaningful to study the
β-substituted phenylacrylic acid as carboxylic acid ligand in coordination complexes.
In order to further exploring the structural type of the coordination complex and the coordination
mode of central Pb(II) ions, our group synthesized a Pb(II) coordination complex using
2,4-dichlorophenyl
acrylic
acid
(HL)
and
2-(2,4-dichlorophenyl)-1H-
imidazo[4,5-f]-[1,10]phenanthroline (DIPT).
2. Experimental
2.1 Synthesis of 2, 4-dichlorophenyl acrylic acid
The synthesis of HL (Route 1): A mixture of 3.7 g malonic acid (0.035 mol), 4 mL pyridine, 8 mL
toluene, 5.7 g 2, 4-Dichlorobenzaldehyde (0.033 mol), 0.35 mL aniline (catalytic) are added in a
round-bottom flask, added. The mixed solution was refluxed for 3-4 h under electromagnetic stirring,
taken away the solvent by vacuum distillation, added K2CO3 solution and ethyl acetate, then stirred for

15 minutes. The organic layer was neutralized by HCl solution and the resulting solid was washed,
filtered and dried, then obtained target compound. Productivity: 64.6%. Elemental analysis: calcd. (%)
for C9H6O2Cl2: C, 49.80; H, 2.79; found (%): C, 48.04; H, 2.81. IR (KBr, cm-1): 2823(w), 2567(w),
1
1690(s), 1619 (m), 1579(m), 1469(m), 1211(m), 982(m), 862(m), 815(m), 769(m). H NMR (DMSO,
ppm, 400Hz) : 12.71 (s, 1H, H6), 7.96 (d, 3J(H-H) = 8.0 Hz, 1H, H3), 7.81 (d, 3J(H-H) = 16.0 Hz, 1H,
H4), 7.72(s, 1H, H1), 7.48 (d, 3J(H-H) = 8.0 Hz, 1H, H2), 6.65 (d, 3J(H-H) = 16.0 Hz, 1H, H5).
Route 1
2.2 Synthesis of 2-(2,4-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline
The synthesis of DIPT (Route 2): A mixture of 2.2 mL 2,4-dichlorobenzaldehyde (0.020 mol) ,
4.20 g 1,10-Phenanthroline-5,6-dione (0.020 mol), 5.0 g ammonium acetate (0.060 mol), 40 mL
glacial acetic acid were added in a round-bottom flask and the reaction was monitored by TLC
technique. After the reaction ended, reaction mixture was extracted by dichloromethane and resultant
products was purified by column chromatography (benzene : ethyl acetate = 9 : 1). Productivity:
69.8%. Elemental analysis: calcd. (%) for C19H10Cl2N4: C, 62.48; H, 2.76; N, 15.34. found (%): C,
62.04; H, 2.08; N, 14.88. IR (KBr, cm-1): 3379(w), 1672(s), 1554(m), 1096(m), 803(m), 738(m),
562(m). 1H NMR (DMSO, ppm, 400 Hz): 13.97 (s, 1H, H7), 9.07(d, 2H, H3,H4), 8.89 (d, 2H, H1,H6),
7.98 (d, 3J(H-H) = 8.0 Hz, 1H, H8), 7.92 (s, 1H, H10), 7.84(s, 2H, H5,H2),7.69 (d, 3J(H-H) = 8.0 Hz, 1H,
H9).
Route 2
2.3 Synthesis of complex 1
The synthesis of complex 1: 83.44 mg PbCl2 (0.0003 mol), 219.13 mg DIPT (0.0006 mol) and
83.44 mg HL (0.0003 mol) were mixed according to the material ratio of 1 : 2 : 1, added 36 mL tap
water and stirred thoroughly at room temperature for 20min. Then adjusted pH=6.5 with NaOH
solution. The reaction mixture crystallized in a 50 mL Teflon-lined autoclave for 5 days at 160 ℃, and

then cooled to room temperature at 5 ℃/h. A large number of yellow block crystals were obtained at
the bottom of the kettle, washed with distilled water and dried naturally with a yield of 6.8% (in terms
of Pb). The experimental value of element analysis is (%): C, 46.69; H, 1.94; N, 5.05. The theoretical
value of element analysis is (%): C, 46.71;H, 1.95;N, 5.00.
2.4 physical measurements
The IR spectrum was described through Perkin-Elmer 240C spectrometer in the range of
4000~400 cm-1. The UV spectrum was carried out a JASCO V-770 ultraviolet spectrophotometer in
the range of 200~800nm. TGA was performed using a Rigaku Thermo Plus-EVO analyzer in nitrogen
with a heating rate of 10 ℃/min. The luminescence spectra for the powdered solid samples were
measured at room temperature and the spectra were collected with a Hitachi F-4600 fluorescence
spectrometer. Powder X-ray diffraction ( PXRD ) data was recorded on a Rigaku model RINT Ultima
III diffractometer by depositing powder on glass substrate, from 2θ = 1.5° up to 60° with 0.02°
1
increment. The date of H NMR were obtained Bruker AVANCE III HD 400M. The quantum
chemistry calculation of complex 1 was performed with the Gaussian09 program [46] at the
B3LYP/GenECP level (the 6-31+G(d) basis set for C, H, O, N, Cl) and LANL2DZ basis set for Pb).
The initial state structure for the title complex 1 was obtained from the X-ray refinement data (cif).
The initial state structure we adopted the approximate structure model was not optemized, while the
triplet state structure is optemized at the same level.
2.5 X-ray crystallography
Crystal structure measurement was performed on a Bruker SMART APEX II CCD diffractometer
equipped with a graphite-monochromatic Mo Kα (λ = 0.71073 nm) radiation by using the φ and ω
scan mode at 296 (2) K [47]. The structure was solved by direct methods with SHELXS program [48]
and refined with SHELXL-2016/6 [49] by full-matrix least-squares techniques on F2. All
non-hydrogen atoms were refined anisotropically. Crystallographic data and Structure Refinement
parameters for the complex 1 in Table 1. Selected bond lengths (Å) and bond angles (°) are in Table 2.
Hydrogen bond lengths (Å) and bond angles (°) are listed are in Table 3. The Crystallographic data
have been deposited with the Cambridge Crystallographic Data Centre: deposition numbers CCDC
1977916. These data may be obtained free of charge from the Cambridge Crystallographic Data
Center through http:// www.ccdc.cam.ac.uk/data_request/cif.

Table 1. Crystallographic data and Structure Refinement parameters for the complex 1.
Empirical formula
Formula weight
Temperature
C56H28Cl10N8O4Pb
1438.55
296(2) K
Wavelength (Å)
Crystal system
Space group
0.71073
Orthorhombic
Pn21a
a (Å)
33.112(3)
b (Å)
14.3543(15)
c (Å)
11.3282(12)
α (º)
90
β (º)
90
γ (º)
90
Volume (Å3)
5384.3(10)
Z
4
Density ( Mg/m3) calculated
Absorption coefficient (mm-1)
F(000)
1.775
3.687
2816
Crystal size (mm3)
Theta range (°)
Limiting indices
Reflections collected / unique
Refinement method
Data / restraints / parameters
Goodness-of-fit on F2
Final R indices [I > 2σ (I)]
R indices (all data)
Largest diff. peak and hole (e Å-3)
0.28 × 0.26 ×0.25
1.878-25.009
-39 ≤ h ≤ 39, -17 ≤ k ≤ 14, -13 ≤ l ≤ 12
27332 / 8580 [Rint = 0.0479]
Full-matrix least-squares on F2
6914 / 5 / 629
1.048
R1 = 0.0410, wR2 = 0.0939
R1 = 0.0575, wR2 = 0.0999
0.623 and -1.344
Table 2. Selected Bond Lengths (Å) and Bond Angles (°)
Bond
Dist.
Bond
Dist.
Bond
Dist.
Pb-O(1)
Pb-N(1)
Angle
2.486(9)
2.527(4)
(°)
Pb-O(3)
Pb-N(2)
Angle
2.643(9)
2.549(5)
(°)
Pb-N(6)
Pb-N(5)
Angle
2.795(5)
2.709(6)
(°)
O(1)-Pb-O(3)
O(1)-Pb-N(6)
O(3)-Pb-N(5)
N(1)-Pb-N(2)
N(2)-Pb-N(6)
90.4(3)
147.3(3)
134.7(3)
63.9(3)
75.9(3)
O(1)-Pb-N(1)
O(1)-Pb-N(5)
N(1)-Pb-O(3)
N(1)-Pb-N(5)
N(2)-Pb-N(5)
76.1(3)
126.3(3)
141.1(3)
79.4(3)
128.6(3)
O(1)-Pb-N(2)
O(3)-Pb-N(6)
N(1)-Pb-N(6)
N(2)-Pb-O(3)
N(5)-Pb-N(6)
79.8(3)
105.5(3)
73.6(3)
78.0(3)
59.3(3)
Table 3. Hydrogen Bond Lengths (Å) and Bond Angles (°)
D–H···A
d(D–H)
d(H···A)
d(D···A)
∠DHA
N(4)-H(4)···O(4)
0.86
1.88
2.14
2.731(17)
2.898(14)
170.7
N(7)-H(7)···O(1)
0.86
147.3
3. Results and discussion

3.1 Description of crystal structure
It’s interesting that a hydrogen atom on the carbon at position 10 of the DIPT ligand was
replaced by a chlorine atom. According to references[50-51], the Speculative principle is as follows
(Route 3): under a definite temperature and pressure, PbCl2 as a single electron transfer reagent,
captures a single electron on the imidazole ring and causes the DIPT ligand to generate free radical
positive ions. The corresponding resonance formula reacts with PbCl2- and obtains the
10-chloro-2-(2,4-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (CDIPT).
Route 3
The structure of complex 1 is described in Fig. 1, each central Pb(II) is seven-coordinated by
four nitrogen atoms (N1, N2, N5, N6) from two CDIPT ligands and three carboxylate oxygen atoms
(O1, O2, O3) from two different deprotonation of HL, it can be regarded as a distorted
heptacoordinate pentagonal bipyramid in Fig. 2. Deprotonation of HL has two coordination modes:
monodentate bridging and bidentate chelating coordination. The structure analysis shows that the
complex 1 is a zero dimensional structure. There exist hydrogen bonds [ N(4)-H(4)···O(4) and
N(7)-H(7)···O(1) ] between the two bridging ligands CDIPT and deprotonation of HL in the complex
1, there are intermolecular which stabilizes the structure and promote the formation of 2D
supramolecular network (Fig. 3 and 4).

Fig. 1 Crystal structure of the complex 1.
Fig. 2 Coordination environment of the Pb2+.

Fig. 3 Hydrogen bond linking of neighboring molecules (Some atoms are omitted).
Fig. 4 The 2D structure of complex 1 .
3.2 IR spectrum

Fig. 5 IR spectra of complex 1.
IR spectra of complex 1 was shown in Fig.5. From the infrared spectra of complex 1, the main
characteristic peaks of complex 1 are 3430, 3064, 1633, 1530, 1456, 1430, 1371, 1278, 1092, 1041,
973, 812,736 cm-1. At 3430 cm-1, the absorption peak is wide and scattered, which indicates that the
complex 1 contains water. The peak at 3064 cm-1 is mainly the stretching vibration of C-H(-C=C-H)
[52]. At 1633, 1530 cm-1, they should be attributed to the asymmetric stretching vibration absorption
peak of C=O on the carboxyl group, and at 1456, 1430 cm-1, they should be classified as the
symmetric stretching vibration absorption peak of C=O, indicating that the carboxyl group in the
ligand participates in coordination [53] and the coordination pattern of carboxyl group are single
dentate bridging and double dentate chelating. The peak at 1371 cm-1 should be attributed to the
stretching vibration of C-N. Around 1092 cm-1, this region mainly includes the in-plane bending
vibration of C-H [54], stretching vibration of C-Cl, and single-bond skeleton vibration of C-C. At 812
and 736 cm-1, there are the characteristic peaks of substituted aromatic ring [55]. It is consistent with
the results of elemental analysis and single crystal structure analysis of the complex 1.
3.3 UV spectrum and Fluorescence spectrum
Its solid UV spectrum and fluorescence spectrum are studied. The relationship between structure
and property is discussed.
The UV spectrum was used to test the wavelength range of 200-800 nm, as shown in Fig. 6. The
ligand HL has a strong absorption peak at 200-380 nm, the DIPT has a strong absorption peak at
200-450 nm. Similarly, the complex 1 has shown strong peak at 200-500nm can be assigned to π→π*
transition of the aromatic ring and n→π* transition of the carboxyl, one weaker peak at 500-520 nm
and presumably originates from metal-to-ligand transition. The shift in the position and strength of
the characteristic absorption peaks are due to the redistribution of the electron cloud and electron
transfer between the ligands and metal ions after the coordination between the metal ions and ligands.

Fig. 6 UV spectrum of the ligands and complex 1
The solid state luminescent properties of complex 1, ligand HL and DIPT have been tested at
room temperature and the fluorescence emission spectra of them are illustrated in Fig. 7. the
excitation wavelength of HL, DIPT and complex 1 has also tested (insert of Fig.7). The emission peak
of the ligand HL is located at 408 nm (excitation at 320 nm) and the ligand DIPT is located at 426 nm
(excitation at 352 nm), the emission spectrum of complex 1 shows a maximum emission wavelength
at 481 nm (excitation at 384 nm). Compared to the ligand DIPT and HL, complex 1 exhibits a
significant red shift, which can be assigned to the formation of the complex. Fluorescence analysis
showed that the complex had good optical properties and could be used as a potential optical material
[56].
Fig. 7 Emission spectrum of ligands and complex 1 in solid state.
3.4 PXRD and Thermal Analyses
PXRD of complex 1 was carried out at room temperature in order to confirm the phase purity in

Fig. 8. The experimental PXRD pattern is closely matched with the simulated pattern from
single-crystal structure, revealing the good phase purity of the bulk crystalline material.
Fig.8 PXRD patterns of complex 1.
The TGA experiment was performed under N2 atmosphere at a heating rate of 10 ℃/min. As
shown in Fig. 9, the anhydrous complex 1 begins to decompose at 270 ℃ and ends above 470 ℃.
Within the temperature range of 50-800 ℃, only one section of weightlessness of complex 1
corresponds to the loss of organic ligands, and the final residual is the oxide of Pb. The
weightlessness of the whole process is 85.12 % (theoretical estimate of 84.48%). In conclusion, the
thermal data is in reasonable agreement with the crystal structure analysis and complex 1 exhibited
good thermal stability.
Fig. 9 TGA curves of complex 1
3.5 Theoretical Calculation

The calculation covered 107 atoms, 1508 basis functions, 2860 primitive gaussians, 313 α
electrons and 313 β electrons for the model of complex 1. The total molecular energy is
=-203942.207 eV, the energies of HOMO and LUMO are -3.126 eV and -5.344 eV, respectively, with
the ΔE (ELUMO-EHOMO) value to be 2.219 eV. Selected atom net charges and electronic configuration
of the title complex at the B3LYP/(6-31 + G(d) (for C, H, O, N and Cl) and LANL2DZ (for Pb) levels
are listed in Table 4. The calculation results show that electronic configurations of the central Pb atom
is 6S1.966p0.537p0.02, N atoms are 2S1.38~1.392p4.04~4.083S0.013p0.01~0.0247p0.01and those of O and Cl atoms
are 2S1.70~1.722p4.99~5.063S0.013p0.02~0.033d0.01~0.02and 3S1.86~1.873p25.11~5.123d0.01. It can be concluded from
the calculation that the coordination of Pb(II) ion with N and O atoms is mainly on the 2s and 2p
orbitals. All O atoms give electrons to the Pb(II) ion in the 2s, 2p, 3d orbitals and form coordination
bonds. N atoms form coordination bonds with Pb(II) ion through 2s, 2p and 3p orbitals. So the Pb(II)
ion gets some electrons from the O atoms of the deprotonation of HL ligand and the N atoms of the
CDIPT ligand. N1, N2, N5, N6, O1, O2, O3 have more negative charges, generally speaking, the
more negative charges, the stronger nucleophilicity, the stronger its ability to form coordination
complexes with the metals. Thus, according to valence-bond theory the atomic net charge distribution
in the HL and CDIPT show obvious covalent interactions between the coordinated atoms and Pb(II)
ion.
Table 4 Selected atom net charges and electronic configuration of complex 1 at the B3LYP/(6-31 +G(d) (for C, H,
O, N and Cl) and Lanl2dz (for Pb) levels
Atom
Pb
Charge
1.494
Electron configuration
[core]6S(1.96)6p( 0.53)7p( 0.02)
[core]2S(1.38)2p( 4.08)3p( 0.02)4p( 0.01)
[core]2S(1.39)2p( 4.07)3p( 0.02)
[core]2S(1.39)2p( 4.04)3S( 0.01)3p( 0.02)4p( 0.01)
[core]2S(1.39)2p( 4.05)3p( 0.02)
[core]2S(1.71)2p( 5.03)3p( 0.02)3d( 0.01)
[core]2S(1.71)2p( 5.04)3p( 0.03)3d( 0.02)
[core]2S(1.70)2p( 5.06)3d( 0.01)
[core]2S(1.72)2p( 4.99)3S( 0.01)
[core]3S(1.86)3p( 5.11)3d( 0.01)
[core]3S(1.87)3p( 5.12)3d( 0.01)
N1
N2
N5
N6
O1
O2
O3
O4
Cl1
Cl4
-0.493
-0.483
-0.463
-0.460
-0.776
-0.797
-0.778
-0.722
0.016
-0.003
UV spectral analysis of complex 1 has been investigated by TD-DFT method (Fig. 10). It can be
seen from the UV visible spectra, the calculated absorption maximum values has been found to be
341nm. The calculated absorption value is in good agreement with the experimental result.

Fig. 10 Calculated and experimental absorption values of complex 1.
The 341 nm absorption peak is mainly due to the transition of electrons from the HOMO-2
orbital to the LUMO orbital, it contributed 56.43 % of the main absorption peak. The others,
HOMO-3 → LUMO, 4.84 %; HOMO-1 → LUMO, 3.37 %; HOMO-1 → LUMO+1, 31.17 %;
HOMO-1 → LUMO+3, 4.19%. According to molecular orbital theory, HOMO has the important role
of giving electrons first, while LUMO receiving electrons. The HOMO and LUMO are presented in
Fig. 11, The HUMO-2 orbital electron cloud is provided by the double bond carbon atoms on the
deprotonation of HL ligand molecule and the whole CDIPT molecule, after absorbing the light
energy, it jumped to the CDIPT ligand molecule on the LUMO orbital.
Fig. 11 The molecular orbitals of the complex 1.
In the emission spectrum, complex 1 has the maximum luminescence intensity at 481 nm. In
calculation, the optemized triplet state has an emission peak of 532.9 nm as a difference between

triplet and ground singlet states at ground state molecular geometry, it is very close to the
experimental results. And the calculation indicates that the complex 1 emitted fluorescence.
Fig. 12 Calculated and experimental emission peak of complex 1.
4. Conclusion
In this work, a new 0 dimensional Pb(II) complex has been successfully synthesized by using
DIPT as a nitrogen-donor ligand and HL as an oxygen-donor carboxylic acid. The complex 1 was
analyzed by single-crystal X-ray diffraction analysis and the result showed that seven coordination
Pb(II) presents a distorted heptacoordinate pentagonal bipyramid structure. The complexes formed a
two-dimensional network by intermolecular hydrogen bonds. The calculation results showed
reasonable electronic configurations of the central Pb atom and the existence of the coordination bond
in the complex is fully confirmed. The theoretical results of the calculated absorption and emission
values are close to those of experiments. In addition, the complex which has good thermal stability
and red shift in solid state, is expected to be further applied in the future.
Author Contributions Section
He Wang : Investigation,Synthesized, Writing- Reviewing, Editing
Shuang Han: Investigation,Collecting data,Validation
Linan Dun: Investigation, Characterized
Baosheng Zhang: Investigation, Characterized
Xue Chen: Investigation, Characterized
Jiajun Wang: Conceptualization, Methodology, Investigation
Chuanbi Li: Conceptualization, Methodology, Investigation
Chunling Liu: Supervision, Conceptualization, Methodology, Investigation, Editing
Declaration of interests

 The authors declare that they have no known competing financial interests or personal
relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
We thank the National Natural Science Foundation of China (No.21805110) for financial
support.
REFERENCES
[1] C.Gao, J.Wang, H.Xu, Y.Xiong, Coordination chemistry in the design of heterogeneous photocatalysts.
Chem.Soc.Rev. 46(2017)2799-2823. https://doi.org/10.1039/C6CS00727A
[2] A.Q.Wu, Y.Li, F.K.Zheng, Guo, J.S.Huang, Different molecular frameworks of zinc(II) and cadmium(II)
coordination polymers constructed by flflexible double betaine ligands, Cryst. Growth Des. 6 (2006) 444-450.
https://doi.org/10.1021/cg050378e
[3] D.Yuan, Y.Li, W.Li, S.Li, Structures and properties of large supramolecular coordination complexes predicted with
the generalized energy-based fragmentation method, Phys.Chem.Chem.Phys. 2018(20)28894-28902.
https://doi.org/10.1039/C8CP05548C
[4] A.J.Timmons, M.D.Symes, Converting between the oxides of nitrogen using metal–ligand coordination complexes,
Chem.Soc.Rev. 44(2015)6708-6722. https://doi.org/10.1039/C5CS00269A
[5] J.Crassous, Chiral transfer in coordination complexes: towards molecular materials, Chem.Soc. Rev.
38(2009)830-845. https://doi.org/10.1039/B806203J
[6] Y.Mao, Q.Kong, B.Guo, X.Fang, X.Guo, L.Shen, A.Michel, Chen.L, Polypyrrole-iron-oxygen coordination
complex as high performance lithium storage material, Energy Environ.Sci. 4(2011)3442-3447.
https://doi.org/10.1039/C1EE01275D
[7] F.A.Mautner, R.C.Fischer, K.Reichmann, E.Gullett, K.Ashkar, S.S.Massoud, Synthesis and characterization of 1D
and 2D cadmium(II)-2,2′-bipyridine-N,N′-dioxide coordination polymers bridged by pseudohalides, J.Mol.Struct.
1175(2019) 797-803. https://doi.org/10.1016/j.molstruc.2018.08.022
[8] S.Gayen, D.Saha, S.Koner, Quinoline derivative containing monomeric and polymeric metal carboxylates:
Synthesis, crystal structure and gas adsorption study over a 2D layered framework, J.Mol.Struct. 1162(2018)10-16.
https://doi.org/10.1016/j.molstruc.2018.02.090
[9] G.G.Sezer, O.Z.Yeşilel, O.Büyükgüngör, Two 3D Zinc(II) coordination frameworks constructed from
pyrazine-2,3-dicarboxylate
and
1,2-bis(4-pyridyl)ethylene,
J.Mol.Struct.
1137(2017)562-568.
https://doi.org/10.1016/j.molstruc.2017.02.077
[10] J.A.Brant, Y.Liu, D.F.Sava, D.Beauchamp, M.Eddaoudi, Single-metal-ion-based molecular building blocks
(MBBs) approach to the design and synthesis of metal–organic assemblies. J.Mol.Struct. 796(2006)160-164.
https://doi.org/10.1016/j.molstruc.2006.02.064
[11] V.V.Butova, M.A.Soldatov, A.A.Guda, K.A.Lomachenko, C.Lamberti, Metal-organic frameworks: Structure,
properties,
methods
of
synthesis
and
characterization,
Russ.Chem.Rev.
85(2016)
280-307.
https://doi.org/10.1070/rcr4554
[12] T.Uemura, N.Yanai, S.Kitagawa, Polymerization reactions in porous coordination polymers, Chem.Soc.Rev. 38
(2009) 1228-1236. https://doi.org/10.1039/B802583P
[13] B.C.Félix-Sonda, J.Rivera-Islas, D.Herrera-Ruiz, H.Morales-Rojas, H.Höpfl, Nitazoxanide cocrystals in
combination with succinic, glutaric, and 2,5-dihydroxybenzoic acid, Cryst.Growth Des. 14(2014)1086-1102.
https://doi.org/10.1021/cg4015916
[14] Y.Tümer, N.Asmafiliz, Z.Kılıç, T.Hökelek, L.Y.Koç, L.Açık, M.L.Yola, A.O.Solak, Y.Öner, D.Dündar, M. Yavuz,
Phosphorus–nitrogen compounds: Part 28. Syntheses, structural characterizations, antimicrobial and cytotoxic
activities, and DNA interactions of new phosphazenes bearing vanillinato and pendant ferrocenyl groups, J.Mol.Struct.
1049 (2013)112-124. https://doi.org/10.1016/j.molstruc.2013.06.036
[15] H.Agarkar, D.Das, The photo-switching study of guest 2-(phenylazo)pyridine(PAP) embedded in solid host
material MOF-5, J.Mol.Struct. 1184(2019)435-442. https://doi.org/10.1016/j.molstruc.2019.02.059

[16] Kh.S.Abou-El-Sherbini, M.M.Hassanien, Synthesis of controlled-pore silica glas functionalized with quercetin
and its application for the separation and preconcentration of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II),
Sep.Sci.Technol. 39(2004)1177-1201. https://doi.org/10.1081/SS-120028578
[17] R.F.V.Souza, W.F.Giovani, Synthesis, spectral and electrochemical properties of Al(III) and Zn(II) complexes
with flavonoids, Spectrochim. Acta A. 61(2005)1985-1990. https://doi.org/10.1016/j.saa.2004.07.029
[18] M.Ghoreishi Amiri, G.Mahmoudi, A.Morsali, A.D.Hunter, M.Zeller, Zinc(II) nitrite coordination polymers based
on
rigid
and
flexible
organic
nitrogen
donor
ligands,
CrystEngComm.
9(2007)686-697.
https://doi.org/10.1039/B701711A
[19] H.Sadeghzadeh, A.Morsali, P.Retailleau, Ultrasonic-assisted synthesis of two new nano-structured 3D lead(II)
coordination polymers: precursors for preparation of PbO nano-structures, Polyhedron. 29(2010)925-933.
https://doi.org/10.1016/j.poly.2009.10.026
[20] A.A.Soudi, F.Marandi, A.Morsali, L.G.Zhu, [Pb2(2,2′-bipy)2(μ-4,4′-bipy)(NO3)4]: A novel hemidirected dimeric
mixed-ligands lead(II) complex extended in holodirected two-dimensional polymer by weak Pb–Onitrate interactions,
Inorg.Chem.Commun. 8 (2005)773-776. https://doi.org/10.1016/j.inoche.2005.05.016
[21] H.Ahmadzadi, F. Marandi, A. Morsali, Structural and X-ray powder diffraction studies of nano-structured lead(II)
coordination
https://doi.org/10.1016/j.jorganchem.2009.07.016
[22] J.X.Li, Z.X.Du, A Binuclear Cadmium(II) Cluster Based on π···π Stacking and Halogen···Halogen Interactions:
Synthesis, Crystal Analysis and Fluorescent Properties, J.Clust.Sci. 31(2020)507-511.
https://doi.org/10.1007/s10876-019-01666-w
[23] X.X.Xu, Y.Ma, E.B.Wang, Different aliphatic dicarboxylates affected assemble of new coordination polymers
constructed from flexible-rigid mixed ligands, J.Solid State Chem. 180(2007)3136-3145.
https://doi.org/10.1016/j.jssc.2007.05.033
[24] L.G.Yu, Y.G.Sun, Z.L.Wang, Mixed-ligand strategy affording two new metal-organic frameworks: Photocatalytic,
luminescent and anti-lung cancer properties, J.Mol.Struct. 1180(2019)209-214.
https://doi.org/10.1016/j.molstruc.2018.11.063
polymer
with
η2
Pb···C
interactions,
J.Organomet.Chem.
694(2009)3565-3569.
[25] J.N.Clifford, E.Martínez-Ferrero, A.Viterisi, E.Palomares, Sensitizer molecular structure-device efficiency
relationship in dye sensitized solar cells, Chem.Soc.Rev. 40(2011)1635-1646. https://doi.org/10.1039/B920664G
[26] M.Gollapalli, M.Taha, H.Ullah, M.Nawaz, L.M.R.AlMuqarrabun, F.Rahim, F.Qureshi, A.Mosaddik, N.Ahmat,
K.M.Khan, Synthesis of Bis-indolylmethane sulfonohydrazides derivatives as potent α-Glucosidase inhibitors,
Bioorg.Chem. 80(2018)112-120. https://doi.org/10.1016/j.bioorg.2018.06.001
[27] H.Yasui, A.Tamura, T.Takino, H.Sakurai, Structure-dependent metal-lokinetics of antidiabetic vanadyl-picolinate
complexes in rats: Studies on solution structure, insulinomimetic activity and metallokinetics, J.Inorg.Biochem.
91(2002)327-338. https://doi.org/10.1016/S0162-0134(02)00443-9
[28] A.A.El-Habeeb, M.S.Refat, Synthesis, structure interpretation, antimicrobial and anticancer studies of tranexamic
acid complexes towards Ga(III), W(VI), Y(III) and Si(IV) metal ions, J.Mol.Struct. 1175(2019)65-72.
https://doi.org/10.1016/j.molstruc.2018.07.099
[29] S.Gorduk, A.Altindal, Peripherally tetra-substituted metallophthalocyanines bearing carboxylic acid groups for
efficient dye sensitized solar cells, J.Mol.Struct. 1196(2019)747-753. https://doi.org/10.1016/j.molstruc.2019.07.027
[30] J.W.Zhang, R.J.Zhang, Y.Man, B.Q.Liu, Y.P.Dong, A new metal-organic framework constructed from Cu(II) and
3-bromo-5-(4-carboxyphenyl)pyridine: Synthesis, structure, photoluminescent and magnetic properties, J.Mol.Struct.
1185(2019)276-280. https://doi.org/10.1016/j.molstruc.2019.02.046
[31] S.Zhao, A novel 3D MOF with rich lewis basic sites as a base catalysis toward knoevenagel condensation reaction,
J.Mol.Struct. 1167(2018)11-15. https://doi.org/10.1016/j.molstruc.2018.04.078
[32] L.Yang, L.Guo, Q.Chen, H.Sun, J.Liu, X.Zhang, X.Pan, S.Dai, Theoretical design and screening of panchromatic
phthalocyanine sensitizers derived from TT1 for dye-sensitized solar cells, J.Mol.Graph.Model. 34 (2012)1-9.
https://doi.org/10.1016/j.jmgm.2011.12.001
[33] H.Furukawa, O.M.Yaghi, Storage of hydrogen, methane, and carbon dioxide in highly porous covalent organic
frameworks for clean energy applications, J.Am.Chem.Soc. 131(2009)8875-8883. https://doi.org/10.1021/ja9015765
[34] Y.L.Wu, G.P.Yang, S.Cheng, J.J.Q, Y.Y.Wang, Facile incorporation of Au nanoparticles into an unusual two-fold
entangled Zn(II)-MOF with nano-cages for highly efficient CO2 fixation under the mild conditions, ACS Appl.Mater.
Interfaces. 11(2019)47437-47445. https://doi.org/10.1021/acsami.9b17348
[35] H.Pervez, N.Khan, J.Iqbal, S.Zaib, M.Yaqub, M.M.Naseer, Synthesis and in vitro bio-activity evaluation of
N4-benzyl substituted 5-chloroisatin-3-thiosemicarbazones as urease and glycation inhibitors, Acta Chim.Slov. 65
(2018)108-118. https://doi.org/10.17344/acsi.2017.3649
[36] C.B.Sangani, N.M.Shah, M.P.Patel, R.G.Patel, Microwave-assisted synthesis of novel 4H-chromene derivatives
bearing phenoxypyrazole and their antimicrobial activity assessment, J. Serb.Chem. Soc. 77 (2012) 1165-1174.
https://doi.org/10.2298/JSC120102030S
[37] S.Naseem, M.Khalid, M.N.Tahir, M.A.Halim, A.A.C.Braga, M.M.Naseer, Z.Shafiq, Synthesis, structural, DFT
studies, docking and antibacterial activity of a xanthene based hydrazone ligand, J.Mol.Struct. 1143(2017)235-244.
https://doi.org/10.1016/j.molstruc.2017.04.093

[38] T.Raj, R.K.Bhatia, A.Kapur, M.Sharma, A.K.Saxena, M.P.S.Ishar, Cytotoxic activity of 3-(5-phenyl-3H-[1,2,4]
dithiazol-3-yl)chromen-4-ones and 4-oxo-4H-chromene-3-carbothioic acid N-phenylamides, Eur.J.Med.Chem. 45
(2010)790-794. https://doi.org/10.1016/j.ejmech.2009.11.001
[39] N.Touj, A.Chakchouk-Mtibaa, L.Mansour, A.H.Harrath, J.Al-Tamimi, L.Mellouli, I.Özdemir, S.Yasar,
N.Hamdi, Synthesis, spectroscopic properties and biological activity of new Cu(I) N-Heterocyclic carbene complexes,
J.Mol.Struct. 1181(2019)209-219. https://doi.org/10.1016/j.molstruc.2018.12.093
[40] M.M.Mohamed. El-Bendary, T.Rüffer, M.N.Arshad, A.M.Asiri, Synthesis and structure characterization of Pt(IV)
and Cd(II) 1,10-phenanthroline complexes; fluorescence, antitumor and photocatalytic property, J.Mol.Struct.
1192(2019)230-240. https://doi.org/10.1016/j.molstruc.2019.04.115
[41] Y.W.Niu, X.Liu, L.Zhao, Y.M.Guo, W.X.Li, M.M.Ma, X.L.Li, Synthesis, structures and photophysical properties
of four binuclear Cu(I) complexes of 1H-imidazo[4,5-f][1,10]phenanthroline, Polyhedron. 157(2019)241-248.
https://doi.org/10.1016/j.poly.2018.10.016
[42] F.Chen, J.Wang, M.W.Dong, S.L.Zhang, C.P.Wu, J.Q.Liu, Five lanthanide supramolecular frameworks based on
mixed 3-(4-hydroxyphenyl)propanoic acid and 1,10-phenanthroline tectons: Crystal structures and luminescent
properties, J.Mol.Struct. 1177(2019)117-123. https://doi.org/10.1016/j.molstruc.2018.09.032
[43] S.Hemalatha, J.Dharmaraja, S.Shobana, P.Subbaraj, T.Esakkidurai, N.Raman, Chemical and Pharmacological
aspects of Novel Hetero MLB complexes derived from NO2 type Schiff base and N2 type 1,10–Phenanthroline ligands,
J.Saudi.Chem.Soc. 24(2020)61-80. https://doi.org/10.1016/j.jscs.2019.09.004
[44] S.Han, H.Wang, J.J.Wang, L.N.Dun, C.B.Li, C.L. Liu, Synthesis, crystal structure and theoretical
calculation of triphenyltin (IV) polymer based on 2,4-dichlorophenylacrylic acid, Inorg.Nano-Met.Chem.
50(2020)187-193. https://doi.org/10.1080/24701556.2019.1703747
[45] H.Y.Sun, Z.R.Wang, X.Li, S.Han, J.J.Wang, W.F.Li, C.L.Liu, C.B.Li, A novel Co(II) based multifunctional
metal-organic framework: synthesis, fluorescence sensing and magnetic analysis, Inorg.Chim.Acta. 486(2019)
750-756. https://doi.org/10.1016/j.ica.2018.11.028
[46] G.W.T.M.J.Frisch, H.B.Schlegel, G.E.Scuseria, M.A.Robb, J.R.Cheeseman, G.Scalmani, V.Barone, B.Mennucci,
G.A.Petersson, H.Nakatsuji, M.Caricato, X.Li, H.P.Hratchian, A.F.Izmaylov, J.Bloino, G.Zheng, J.L.Sonnenberg, M.
Hada, M.Ehara, K.Toyota, R.Fukuda, J.Hasegawa, M.Ishida, T.Nakajima, Y.Honda, O.Kitao, H.Nakai, T.Vreven, J.A.Jr.
Montgomery, J.E.Peralta, F.Ogliaro, M.Bearpark, J.J.Heyd, E.Brothers, K.N.Kudin, V.N.Staroverov, R.Kobayashi, J.
Normand, K.Raghavachari, A.Rendell, J.C.Burant, S.S.Iyengar, J.Tomasi, M.Cossi, N.Rega, J.M.Millam, M.Klene,
J.E.Knox, J.B.Cross, V.Bakken, C.Adamo, J.Jaramillo, R.Gomperts, R.E.Stratmann, O.Yazyev, A.J.Austin, R.Cammi,
C.Pomelli, J.W.Ochterski, R.L.Martin, K.Morokuma, V.G.Zakrzewski, G.A.Voth, P.Salvador, J.J.Dannenberg, S.
Dapprich, A.D.Daniels, O.Farkas, J.B.Foresman, J.V.Ortiz, J.Cioslowski, D.J.Fox, Gaussian 09 (Gaussian, Inc.,
Wallingford CT, 2009).
[47] A.L.Spek, Structure validation in chemical crystallography. Acta Cryst. D. 65(2009)148-155.
https://doi.org/10.1107/S090744490804362X
[48] G.M.Sheldrick, SHELXS97 and SHELXL97, University of Göttingen, Germany, 1997.
[49] G.M.Sheldrick,.
Crystal
structure
refinement
with
SHELXL.
Acta
Cryst.C.
71(2015)3-8.
https://doi.org/10.1107/S2053229614024218
[50] E. Balong-Hergovich, G. Speier, ChemInform Abstract: The Chlorination of Indoles by Copper(II) Chloride.
18(1986)2305-2308. J. CHEM. SOC. PERKIN TRANS. I .https://doi.org/10.1039/P19860002305
[51] D. Y.B., L. Y.C., Progress in the Generation and Structural Study of Origanic Radical Cations, CHINESE
J.ORG.CHEM. 10(1990)488-497.
[52] D.Li-Vien, N.B.Colthup, W.G.Fateley, J.G.Grasselli, The Handbook of Infrared and Raman Characteristic
Frequencies of Organic Molecules, Academic Press, Boston, 1991.
[53] S.Lin, L.Zeng, G.Zhang, Y.Liao, D.Gong, Synthesis, characterization and xanthine oxidase inhibition of
Cu(II)-chrysin
https://doi.org/10.1016/j.saa.2017.01.056
[54] L.J.Bellamy, The Infrared Spectra of Complex Molecule, third ed., Willey, New York, 1975.
complex,
Spectrochim.
Acta
A
Mol.
Biomol.
Spectrosc.
178(2017)71-78.
[55] G.Varsanyi, Assignments of Vibrational Spectra of Seven Hundred Benzene Derivatives, vol. 1, Adam Higher,
England, 1974.
[56] A.Srivastava, R.Mishra, S.Kumar, K.Dev, P.Tandon, R.Maurya, Molecular structure, spectral investigation (1H
NMR, 13CNMR, UV-Visible, FT-IR, FT-Raman), NBO, intramolecular hydrogen bonding, chemical reactivity and first
hyperpolarizability analysis of formononetin [7-hydroxy-3(4-methoxyphenyl)chromone]: A quantum chemical study,
J.Mol.Struct. 1084(2015) 55-73. https://doi.org/10.1016/j.molstruc.2014.11.070

Graphical abstract
A
new
coordination
complex
Pb(CDIPT)2(L)2
(1)
was
synthesized
with
2-(2,4-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (DIPT) and 2,4-dichlorophenyl
acrylic acid(HL). Complex 1 was characterized by elemental analysis, IR spectroscopy, PXRD and
single-crystal X-ray diffraction analysis. Each central Pb ion is a distorted heptacoordinate pentagonal
bipyramid by four nitrogen atoms from two DIPT ligands and three carboxylate oxygen atoms from
two different deprotonation of HL. Based on this, the properties of the complex 1 were further studied,
fluorescence spectra showed that the complex has obvious red shift. TGA indicated that the complex
has good thermal stability. In addition, the complex was calculated by quantization method. The
stability and bonding characteristics of the complex were described, which were in good agreement
with the experimental results.