Containing-PMBP N2O2-donors transition metal(II) complexes: Synthesis, crystal structure, Hirshfeld surface analyses and fluorescence properties

Article abstract of DOI:10.1002/aoc.5013

Three newly designed containing-PMBP N₂O₂-donors complexes, [Co(L¹)(CH₃OH)₂] (1), [{Zn(L²)(CH₃OH)(H₂O)}₃] (2) and [Cu₄(L²)₄]?2CHCl₃ (3), have been synthesized and structurally characterized using elemental analyses, infrared and UV–visible spectroscopies and single-crystal X-ray diffraction. X-ray crystal structure determinations revealed that 1 consists of one Co(II) atom, one completely deprotonated (L¹)^2? unit and two coordinated methanol molecules. Complex 2 consists of three Zn(II) atoms, three completely deprotonated (L²)^2? units, three coordinated methanol molecules and three coordinated water molecules. However, 3 includes four Cu(II) atoms, four completely deprotonated (L²)^2? units and two crystallization chloroform molecules. The Co(II) and Zn(II) atoms in the structures of 1 and 2 adopt slightly distorted octahedral geometries. While, Cu(II) atoms in 3 can be best described as adopting slightly distorted square planar geometries. Complex 2 is a novel structure, and the ratio of H₂L² to Zn(II) atom is 3:3. In addition, two-, three- and three-dimensional supramolecular structures were constructed for 1, 2 and 3. Most importantly, Hirshfeld surface analysis of 1, 2 and 3 was conducted and fluorescence properties were investigated.

Full text of DOI:10.1002/aoc.5013

Received: 15 January 2019
DOI: 10.1002/aoc.5013
Revised: 5 May 2019
Accepted: 6 May 2019
F U L L P A P E R
Containing‐PMBP N O ‐donors transition metal(II)
2
2
complexes: Synthesis, crystal structure, Hirshfeld surface
analyses and fluorescence properties
Quan‐Peng Kang | Xiao‐Yan Li | Lan Wang | Yang Zhang | Wen‐Kui Dong
School of Chemical and Biological
1
Three newly designed containing‐PMBP N O ‐donors complexes, [Co(L )
Engineering, Lanzhou Jiaotong
2 2
2
2
University, Lanzhou 730070, China
(
CH OH) ] (1), [{Zn(L )(CH OH)(H O)} ] (2) and [Cu (L ) ]⋅2CHCl (3), have
3
2
3
2
3
4
4
3
been synthesized and structurally characterized using elemental analyses,
infrared and UV–visible spectroscopies and single‐crystal X‐ray diffraction. X‐
ray crystal structure determinations revealed that 1 consists of one Co(II) atom,
Correspondence
Wen‐Kui Dong, School of Chemical and
Biological Engineering, Lanzhou Jiaotong
University. Lanzhou 730070, China.
Email: dongwk@126.com
1
2−
one completely deprotonated (L ) unit and two coordinated methanol mole-
cules. Complex 2 consists of three Zn(II) atoms, three completely deprotonated
2 2−
Funding information
(
L ) units, three coordinated methanol molecules and three coordinated
Program for Excellent Team of Scientific
Research in Lanzhou Jiaotong University,
Grant/Award Number: 201706; National
Natural Science Foundation of China,
Grant/Award Number: 21761018
water molecules. However, 3 includes four Cu(II) atoms, four completely
2
2−
deprotonated (L ) units and two crystallization chloroform molecules. The
Co(II) and Zn(II) atoms in the structures of 1 and 2 adopt slightly distorted
octahedral geometries. While, Cu(II) atoms in 3 can be best described as
adopting slightly distorted square planar geometries. Complex 2 is a novel
2
structure, and the ratio of H L to Zn(II) atom is 3:3. In addition, two‐,
2
three‐ and three‐dimensional supramolecular structures were constructed for
1
, 2 and 3. Most importantly, Hirshfeld surface analysis of 1, 2 and 3 was con-
ducted and fluorescence properties were investigated.
KEYWORDS
2 2
complex, crystal structure, fluorescence property, N O donor ligands, synthesis
1
| INTRODUCTION
using
an
O‐alkyloxime
(─CH═N─O─(CH2)n
─
O─N═CH─). When an O‐alkyloxime unit substitutes
an imine moiety, the larger electronegativity of the oxy-
gen atoms will improve significantly the electronic behav-
iors of the N O coordination sphere, which may lead to
A Salen‐like compound is a multifunctional tetradentate
N O chelating ligand in modern coordination chemis-
try.
2
2
1–6]
[
A great number of metal coordination com-
2
2
pounds with Salen‐like N O ligands have been
extensively studied for several decades, which have been
variously investigated for potential applications in biolog-
novel structures and better properties of metal com-
2
2
[
42,43]
plexes.
A study has shown that these are at least
4
[44]
10 times more stable than Salen‐like complexes.
the work reported herein, three new complexes, [Co(L )
In
[
7–12]
[13–15]
1
ical fields,
electrochemical conduction,
ion rec-
[16–21]
architectures,[22–26]
2
ognitions,
supramolecular
(CH OH) ] (1), [{Zn(L )(CH OH)(H O)} ] (2) and
3
2
3
2
3
[
27–29]
[30–35]
2
catalysts,
cent
as well as magnetic
and lumines-
[Cu (L ) ]⋅2CHCl (3), constructed from Salamo‐like
4
4
3
[
36–41]
materials. More recently, Salamo‐like N O2
N O donor ligands were prepared and characterized
2 2
2
chelating ligands and their analogues have been explored
structurally.
Appl Organometal Chem. 2019;e5013.
wileyonlinelibrary.com/journal/aoc
© 2019 John Wiley & Sons, Ltd.
1 of 15
https://doi.org/10.1002/aoc.5013

2
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KANG ET AL.
2
| RESULTS AND DISCUSSION
.1 | Infrared (IR) spectra analyses
2
1
2
The IR spectra of H L and H L and their complexes 1, 2
2
2
and 3 show various absorption bands in the 4000–
−
1
4
00 cm region (Figure 1). It is obvious that typical
broad ν(O─H) stretching bands were observed at 3454
−
1
1
2
and 3461 cm in the spectra of H L and H L , respec-
2
2
tively. It is inferred that PMBP molecules in the ligands
1
2
H2L and H2L exist in the enol form. The C═N
1
2
stretching bands of ligands H L and H L appear at
624 and 1619 cm , and the spectra of complexes 1, 2
2
2
−
1
1
and 3 show C═N stretching bands at 1605, 1608 and
−
1
[45,46]
1
615 cm , respectively.
The characteristic C═N
stretching frequencies are shifted to lower values, indicat-
ing that the Co(II), Zn(II) and Cu(II) atoms are coordi-
1
2
FIGURE 1 IR spectra of H
and 3
2 2
L and H L and their complexes 1, 2
1
2
nated with the free ligands H L and H L . The IR
2
2
1
2
spectra of free ligands H L and H L show absorption
2
2
−
1
bands at 1182 and 1179 cm , assignable to Ar─O
1
2
stretching. Compared with H L and H L , the typical
2
2
Ar─O stretching bands of complexes 1, 2 and 3 occurred
−
1
at 1175, 1175 and 1173 cm , respectively. This phenom-
enon can be explained by the formation of M─O bonds
[
47]
(
M = Co, Zn and Cu).
Meanwhile, the free ligand
1
H L exhibited typical aromatic C═C skeleton vibrations
bands at 1505, 1487 and 1459 cm , while for complex 1
these appeared at 1519, 1505 and 1489 cm , respectively.
The free ligand H L also shows aromatic C═C skeleton
vibration bands at 1521, 1486 and 1459 cm , while those
of complex 2 (or 3) appear at 1519, 1492 and 1456 cm
or 1507, 1487 and 1458 cm ), respectively.
2
−
1
−
1
2
2
−
1
−
1
−
1
(
2.2 | UV–visible absorption spectra
1
2
1
2
FIGURE 2 UV–visible spectra of H
complexes 1, 2 and 3
2
L
and H
2
L
and their
The UV–visible absorption spectra of H L and H L with
2
2
those of their complexes 1, 2 and 3 in dimethylformamide
FIGURE 3 (a) View of the molecular structure of complex 1. (b) Coordination polyhedron for the Co(II) atom of complex 1

KANG ET AL.
3 of 15
−
5
(
DMF) solution (1.0 × 10 M) at 298 K are shown in
Figure 2. As the UV–visible absorption spectra of
complexes 1, 2 and 3 are similar, we obtain the same con-
1
clusion. The absorption spectra of the free ligands H L
2
2
and H L exhibit relatively intense absorption peaks at
2
ca 269 and 266 nm, respectively. These absorption peaks
could be attributed to the π–π* type transitions of the ben-
[
48]
zene rings.
Compared to the absorption peaks of the
1
2
free ligands H L and H L , these absorption peaks of
2
2
complexes 1, 2 and 3 are bathochromically shifted to
70, 269 and 271 nm, respectively, indicating the
coordination of Co(II), Zn(II) and Cu(II) atoms with the
2
1
2−
2 2−
[49,50]
(
L )
broad absorption peaks emerge at ca 314, 320 and
09 nm in the spectra of complexes 1, 2 and 3, respec-
or (L )
units.
Meanwhile, new weak
3
tively, which are attributed to the n–π* charge transfer
transitions from the lone‐pair electrons of the N atoms
of C═N groups.
FIGURE 4 View of the intramolecular hydrogen bondings of
complex 1
[
51]
FIGURE 5 Part of the infinite one‐dimensional supramolecular chain of complex 1
FIGURE 6 View of the two‐dimensional supramolecular structure of complex 1 showing the C–H···π and π···π interactions

4
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KANG ET AL.
2
.3 | Crystal structure of complex 1
coordinated methanol molecules at the two axial sites,
resulting in a mononuclear Co(II) complex. The four
atoms of the donor set (N3, N4, O1, O4) and Co1 essen-
tially lie in a plane. The data for Co1–O1 (2.049(3) Å),
Co1–O4 (2.051(3) Å), Co1–O5 (2.113(4) Å), Co1–O6
(2.116(4) Å), Co1–N3 (2.224(4) Å) and Co1–N4
(2.220(4) Å) revealed that the oxygen and nitrogen atoms
take part in coordination with the Co(II) atom. The
The structure of complex 1 is shown in Figure 3. Selected
bond lengths and angles are given in Table S1. The com-
plex [Co(L )(CH OH) ] was isolated, and crystallizes in
the triclinic system, space group P‐1, with Z = 2. In the
Co(II) complex, the molecule consists of one Co(II) atom,
one completely deprotonated (L )
1
3
2
1
2−
unit and two
FIGURE 7 (a) Molecule structure of complex 2 (hydrogen atoms and solvent molecules are omitted for clarity). (b) Coordination
polyhedron for Zn(II) atoms of complex 2
FIGURE 8 View of the intramolecular
hydrogen bondings of complex 2

KANG ET AL.
5 of 15
dihedral angle between the two coordination planes, N3–
Co1–O1 and N4–Co1–O4, is 10.62(9)°, indicating the
coordination geometry around the central Co(II) atom is
a slightly distorted octahedron.
In the crystal structure of complex 1, there are ten sig-
nificant intramolecular hydrogen bondings (C1–H1···N2,
C5–H5A···O1, C18–H18A···O6, C18–H18A···N4, C19–
H19A···O5, C19–H19A···N3, C32–H32···O4, C36–
H36···N5, C37–H37C···O4 and C38–H38C···O1) and two
intermolecular hydrogen bondings (O5–H5···N2 and
O6–H6···N5), which perform a crucial role in construct-
ing and stabilizing the supramolecular structure
[52–54]
(Figure 4). The units are interlinked by the intermolecu-
lar hydrogen bonding interactions into an infinite one‐
dimensional chain supramolecular structure (Figure 5).
In addition, complex 1 molecules are interlinked
effectively via three pairs of C–H···π (C10–H10C···Cg1,
C26–H26···Cg2 and C30–H30B···Cg3) hydrogen bonding
interactions and two pairs of π···π (Cg2···Cg2 and
Cg4···Cg4) stacking interactions (Cg2 = N5–N6–C27–
FIGURE 9 (a) View of the intramolecular hydrogen bondings and (b) three‐dimensional supramolecular structure of complex 2 showing
C–H⋯π hydrogen bonding interactions

6
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KANG ET AL.
C28–C29 and Cg4 = N1–N2–C7–C8–C9), which form an
infinite two‐dimensional layered supramolecular struc-
ture (Figure 6). The hydrogen bonding parameters are
summarized in Table S2.
and three coordinated methanol and three coordinated
water molecules. The three Zn(II) atoms are located in
the N O2 coordination spheres, and hexa‐coordinated
2
with donor N O atoms and two other oxygen atoms
2
2
(
O5 and O6) come from the coordinated methanol and
water molecules occupying the axial positions, respec-
tively. The dihedral angle between coordination
planes of N4–Zn1–O4 and N3–Ni1–O1 is 80.88(5)°, which
indicates that the Zn(II) atoms form distorted
octahedral geometries. The primary Zn–N and Zn–O
distances are in the normal ranges (Zn1–O1 = 1.983(7),
2
.4 | Crystal structure of complex 2
The crystal structure of complex 2 is shown in Figure 7.
Selected bond lengths and angles are given in Table S3.
A colorless crystalline complex of rarely reported 3:3 com-
plex [{Zn(L )(CH OH)(H O)} ] was isolated, and crystal-
lizes in the trigonal system, space group R3, with Z = 3.
The molecular structure of complex 2 consists of three
2
Zn1–O5
=
2.099(8), Zn1–O6
=
2.078(8), Zn1–
3
2
3
#
1
O4
=
1.956(8), Zn1–N3
= 2.115(8) and Zn1–
#
1
N4 = 2.111(8) Å) (Table S3). These data revealed that
the oxygen and nitrogen atoms take part in coordination
2
2−
Zn(II) atoms, three completely deprotonated (L ) units,
FIGURE 10 (a) Molecule structure of complex 3 (hydrogen atoms and solvent molecules are omitted for clarity). (b) Coordination
polyhedron for Cu(II) atoms of complex 3
FIGURE 11 View of the intramolecular
hydrogen bondings of complex 3

KANG ET AL.
7 of 15
with the Zn(II) atoms. The bond lengths between the
Zn(II) atom and the apical oxygen atoms (O5 and O6)
are 2.099(8) and 2.078(8) Å, which are obviously longer
than the distances between the Zn(II) atom and the basal
oxygen and nitrogen atoms. This significant elongation
has been observed previously in Zn(II) complexes with
Salamo‐type ligands.
It is worth noting that the center of complex 2 has a
similar cage‐like geometry. The three Zn(II) atoms are
connected through trialkylene chains, resulting in a 24‐
membered ring, which means that complex 2 has better
stability.
As illustrated in Figure 8, in the crystal structure of
complex 2, the structure is connected by five pairs of
intramolecular hydrogen bonding interactions (C17–
H17···O1, C18–H18B···N4, C20–H20B···N3, C33–
H33···O4 and C38–H38A···O4), which play a vital role
in constructing and stabilizing complex 2. In addition,
there are three pairs of intramolecular C–H···π (C18–
H18A···Cg1, C11–H11C···Cg2 and C20–H20A···Cg2) and
FIGURE 12 View of the three‐
dimensional supramolecular structure of
complex 3 exhibiting intermolecular
hydrogen bonding interactions
FIGURE 13 View of the one‐dimensional structure of complex 3 exhibiting C–H···π hydrogen bonding and π···π stacking interactions

8
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KANG ET AL.
FIGURE 14 Hirshfeld surfaces mapped
with dnorm (left), shape_index (middle)
and curvedness (right)
FIGURE 15 Fingerprint plot: full and resolved into C···H/H···C, N···H/H···N and H···H contacts contributing to the total Hirshfeld surface
area of complexes 1, 2 and 3

KANG ET AL.
9 of 15
two pairs of intermolecular C–H···π (C14–H14···Cg3 and
The center Cu1 atom is tetra‐coordinated in a N O plane
2
2
C36–H36···Cg4)
hydrogen
bonding
interactions
by two oxime nitrogen atoms (N3, N6) and two oxygen
2
2−
(Figure 9). Furthermore, every molecule links other mol-
atoms (O1, O5) of the two deprotonated (L ) units.
The Cu(II) atom can be best described as adopting a
slightly distorted square planar geometry with CuN O
ecules via intermolecular C–H···π hydrogen bonds
forming an infinite three‐dimensional supramolecular
2
2
[52–54]
network.
The hydrogen bonding parameters are
coordination. Since there are very weak interactions in
the axial positions with Cu2–O3 of 2.789(1) Å, the interac-
tion between them can be neglected. Therefore, the center
Cu2 atom is also tetra‐coordinated by two oxime nitrogen
atoms (N7, N10) and two oxygen atoms (O7, O8) of two
summarized in Table S4.
2.5 | Crystal structure of complex 3
2
2−
fully deprotonated (L ) units. The axial Cu–O and Cu–
N distances are in the range 1.900(3)–1.987(7) and
1.833(7)–2.004(4) Å, respectively. Additionally, dihedral
angles between the basal planes (N O plane) and another
The structure of complex 3 is presented in Figure 10.
Selected bond lengths and angles are given in Table S5.
The complex [Cu (L ) ]⋅2CHCl was isolated, and crystal-
2
4
4
3
2 2
lizes in the triclinic system, space group P‐1, which
basal plane (N O plane) are 84.38(2)°. It can be seen that
2 2
comprises four Cu(II) atoms, four fully deprotonated
the base plane of Cu1 and the equatorial plane of Cu2 are
almost perpendicular. The dihedral angle of planes N3–
Cu1–O1 and O5–Cu1–N6 is 20.54(2)°. This structure
may be stabilized by the intermolecular contacts
2
2−
(L ) units and two crystallization chloroform molecules.
(
2.883(5) Å) between copper and nitrogen atoms to form
a head‐to‐tail dimer. Unlike previous reports, solvent mol-
[55]
ecules did not participate in the coordination
and
formed a new complex 3.
Meanwhile, in the crystal structure of complex 3, there
are nine significant intramolecular hydrogen bonds
(
Figure 11). As illustrated in Figure 12, complex 3 mole-
cules form an infinite three‐dimensional supramolecular
[52–54]
structure by intermolecular hydrogen bondings,
three pairs of intermolecular hydrogen bonds (C20–
H20···Cl2, C45–H45C···N2 and C75–H75···O8) being
formed. In addition, complex 3 molecules form a one‐
dimensional infinite chain structure via C–H···π and
π···π (Cg3···Cg3) (Cg3 = N1–N2–C7–C8–C9) stacking
interactions (Figure 13). Hydrogen bonding interactions
are detailed in Table S6.
1
2
2 2
FIGURE 16 Emission spectra of H L and H L (λex = 360 nm)
and their complexes 1, 2 and 3 in dilute DMF solution
1
2
FIGURE 17 (a) Fluorescence spectral changes of H L solution upon addition of different amounts of Co(II) ions (0–1.0 equiv.) in DMF
2
+
1 2−
solution. Inset: the absorbance at 415 nm varied as a function of [Co ]/[(L ) ]. (b) Linear relationship between fluorescence intensities and
concentrations of Co(II) ions (λex = 360 nm)

10 of 15
KANG ET AL.
2
.6 | Hirshfeld surface analyses
total Hirshfield surfaces for complexes1, 2 and 3, respec-
tively. Whereas H···H interactions comprise 61.2, 77.8
and 53.2% of the total Hirshfeld surfaces for complexes
1, 2 and 3, respectively. Because there are more hydrogen
atoms in the crystal structures and most of them are
short‐range actions, the interaction between H···H is the
greatest, which is similar to previously reported com-
[56,57]
The Hirshfeld surfaces
of complexes 1, 2 and 3 are
depicted in Figure 14. This figure demonstrates the sur-
face which has been mapped over dnorm, shape_index
and curvedness. In complexes 1, 2 and 3, the main inter-
actions are between the H···H, C···H/H···C and
N···H/H···N surfaces, which are evident on the Hirshfeld
surface, as shown by the bright red spots on the dnorm sur-
face in Figure 14. However, there are several other visible
spots on the Hirshfeld surface.
[
59]
plexes.
As a result of the existence of these hydrogen
bondings, complexes 1, 2 and 3 could be more stabilized.
[58]
Two‐dimensional fingerprint plots
of Hirshfeld sur-
2.7 | Fluorescence spectra
faces for the H···H, C···H/H···C and N···H/H···N interac-
tions are illustrated in Figure 15. These are an important
supplement for the Hirshfeld surface. In addition, tkey
can quantitatively describe the properties and types of
intermolecular interactions between crystals. The extents
of C···H/H···C interactions cover 22.6, 14.3 and 22.2% and
N···H/H···N interactions cover 6.5, 4.4 and 7.9% of the
1
2
The fluorescence properties of H L and H L and their
2
2
complexes were determined at room temperature. The
spectra are shown in Figure 16. The free ligands H L
and H L demonstrated an intense emission peak at ca
416 nm upon excitation at ca 360 nm, which could be
1
2
2
2
[60,61]
attributed to intra‐ligand π–π* transition.
2
FIGURE 18 (a) Fluorescence spectral changes of H
2
L solution upon addition of different amounts of Zn(II) ions (0–1.0 equiv.) in DMF
2
+
2 2−
solution. Inset: the absorbance at 415 nm varied as a function of [Zn ]/[(L ) ]. (b) Linear relationship between fluorescence intensities and
concentrations of Zn(II) ions (λex = 360 nm)
2
FIGURE 19 (a) Fluorescence spectral changes of H
2
L solution upon addition of different amounts of Cu(II) ions (0–1.0 equiv.) in DMF
2
+
2 2−
solution. Inset: the absorbance at 415 nm varied as a function of [Cu ]/[(L ) ]. (b) Linear relationship between fluorescence intensities and
concentrations of Cu(II) ions (λex = 360 nm)

KANG ET AL.
11 of 15
Complexes
1
and
2
demonstrated
weak
However, complex 3 displayed enhanced emission inten-
2
photoluminescence with maximum emission peaks at ca
16 and 510 nm upon excitation at 360 nm, respectively,
sities compared to the corresponding ligand H L , and
2
5
the peaks are bathochromically shifted, which could be
SCHEME 1 Synthetic route to ligands
1
2
H
2
L and H
2
L
TABLE 1 Crystallographic data and refinement parameters for complexes 1, 2 and 3
Parameter
1
2
3
Empirical formula
Formula weight
T (K)
C
38
H
38CoN
6
O
6
C
114
H
114
N
18
O18Zn
3
C
150 6 4 24 16
H130Cl Cu N O
733.69
2220.34
296.15
0.71073
Trigonal
R3
2991.63
173.00(10)
0.71073
Triclinic
P‐1
173.00(10)
0.71073
Triclinic
P‐1
Wavelength (Å)
Crystal system
Space group
a (Å)
9.2446(14)
12.512(2)
15.8811(18)
81.798(11)
78.146(11)
70.492(14)
1689.1(5)
2
20.2381(11)
20.2381(11)
31.3312(15)
90
13.3304(11)
13.9358(11)
21.7616(15)
108.544(7)
94.920(6)
104.045(7)
3659.3(5)
1
b (Å)
c (Å)
α (°)
β (°)
90
γ (°)
120
3
V (Å )
1689.1(5)
3
Z
−
3
Dcalc (g cm
)
1.447
0.995
1.358
−
1
μ (mm
)
0.567
0.537
0.754
F (000)
766.0
3474
1544
Crystal size (mm)
θ range (°)
0.21 × 0.17 × 0.14
3.349–26.022
0.22 × 0.19 × 0.18
0.23 × 0.21 × 0.17
2.413–25.387
3.253–26.022
Index ranges
−11 ≤ h ≤ 10
−24 ≤ h ≤ 24
−23 ≤ k ≤ 24
−35 ≤ l ≤ 37
−16 ≤ h ≤ 16
−17 ≤ k ≤ 17
−21 ≤ l ≤ 26
−
15 ≤ k ≤ 15
19 ≤ l ≤ 19
−
Reflections collected
Unique reflections
11612
27932
25981
6650
8813
14395
R
int
0.0809
0.0858
0.0600
Completeness (%) (θ)
99.7 (25.242)
6650/6/470
1.058
99.9 (25.242)
8813/871/430
1.035
99.7 (25.242)
14395/90/1007
1.038
Data/restraints/parameters
Goodness of fit (GOF)
Final R
, wR
Residuals peak/hole (e Å
1
, wR
2
indices
0.0768, 0.1163
0.1422, 0.1586
0.916 and −0.480
0.0650, 0.1529
0.0893, 0.1663
0.737 and −0.460
0.0776, 0.1754
0.1340, 0.2222
1.340 and −0.675
R
1
2
indices (all data)
−
3
)

12 of 15
KANG ET AL.
[62]
−1
attributed to ligand‐to‐metal charge transfer.
tion, fluorescence titration experiments of complexes 1,
and were conducted in DMF solution
1.0 × 10 M). The results are shown in Figures 17, 18
In addi-
(400–4000 cm ) were recorded using a Vertex 70 FT‐IR
spectrophotometer, with samples prepared as KBr pellets.
UV–visible absorption spectra were recorded with a
2
(
3
−
5
1
Shimadzu UV‐3900 spectrometer. H NMR spectra were
and 19. It can be seen from the fluorescence spectra that
the fluorescence intensities gradually change when differ-
ent metal ions are gradually added. When the amount of
metal ions reached 1.0 equiv., the fluorescence emission
intensity remained relatively constant. Furthermore,
from the emission intensity by following the modified
Benesi–Hidebrand equation, the association constants of
obtained with an AVANCE DRX‐400/600 spectrometer
(Bruker, Germany). X‐ray single‐crystal structure deter-
minations for complexes 1, 2 and 3 were carried out with
SuperNova Dual (Cu at zero) or Bruker APEX‐II CCD dif-
fractometers. Fluorescence spectra were recorded with an
F‐7000 FL spectrophotometer.
5
complexes 1, 2 and 3 were calculated as 2.98 × 10 ,
5
5
−1 [19,21]
4.2 | Synthesis of H L
2
1
.67 × 10 and 3.69 × 10 M .
1,2‐Bis(aminooxy)ethane and 1,3‐bis(aminooxy)propane
3
| CONCLUSIONS
were prepared according to an analogous method
[
63]
reported earlier.
The symmetric N O ‐type ligand
2
2
In summary, three new metal complexes with symmetric
H L was synthesized according to the procedures
2
[
64,65]
N O ‐donors ligands were successfully prepared and char-
reported in earlier literature.
The major synthetic
2
2
1
2
acterized. X‐ray crystal structure analyses revealed the
Co(II) and Zn(II) atoms of complexes 1 and 2 are hexa‐
coordinated and adopt slightly distorted octahedral
coordination geometries. Complexes 1, 2 and 3 possess
self‐assembling infinite two‐, three‐ and three‐
dimensional supramolecular structures via intermolecu-
lar hydrogen bonding and C–H···π and π···π stacking
interactions, respectively. The intermolecular interactions
of the two complexes were discussed in terms of Hirshfeld
route to ligands H L and H L is shown in Scheme 1.
2
2
1
4.2.1 | Synthesis of H2L
To an ethanol solution (15 ml) of PMBP (531.2 mg,
.91 mmol) was added an ethanol solution (5 ml) of 1,2‐
1
bis(aminooxy)ethane (124.6 mg, 1.35 mmol). The mixed
solution was stirred at 55°C for 10 h. After cooling to
room temperature, the precipitates were collected. The
product was dried in vacuo, and a colorless solid was
obtained (Scheme 1). Yield: 493.2 mg, 75.2%. M.p. 201–
surface analyses and two‐dimensional fingerprint plots. In
1
addition, fluorescence behaviors of the ligands H L and
2
2
1
H L were studied. Compared with the ligands H L and
2
2
2
03°C. Anal. calcd for C H N O (%): C, 70.57; H,
2
36 32 6 4
H L , the luminescence intensities of complexes 1 and 3
2
5.26; N, 13.72. Found (%): C, 70.64; H, 5.47; N, 13.58.
decreased significantly. However, the luminescence inten-
sity of complex 2 increased significantly, indicating that
the different ions have different fluorescence effects.
2
4.2.2 | Synthesis of H2L
To an ethanol solution (15 ml) of PMBP (917.4 mg,
4
4
| EXPERIMENTAL
3.30 mmol) was added an ethanol solution (5 ml) of 1,3‐
bis(aminooxy)propane (241.3 mg, 2.28 mmol). The mixed
solution was stirred at 55°C for 10 h. After cooling to
room temperature, the precipitates were collected. The
product was dried in vacuo, and a colorless solid was
obtained (Scheme 1). Yield: 827.3 mg, 71.4%. M.p. 196–
.1 | Materials and physical
measurements
1‐Phenyl‐3‐methyl‐4‐benzoyl‐5‐pyrazolone (PMBP) from
East China Normal University Chemical Plant was used
without further purification. The other reagents and sol-
vents were analytical grade reagents from Tanjin Chemi-
cal Reagent Factory.
1
97°C. Anal. calcd for C H N O (%): C, 70.91; H,
37 34 6 4
5.47; N, 13.41. Found (%): C, 70.82; H, 5.61; N, 13.57.
C, H and N analyses were obtained using a VariuoEL
V3.00 automatic elemental analysis instrument. Elemen-
tal analyses for Co(II), Zn(II) and Cu(II) were conducted
with an IRIS ER/S‐WP–1 ICP atomic emission spectrom-
eter. Melting points were obtained by the use of a micro-
scopic melting point apparatus (Beijing Taike Instrument
Company Limited) and were uncorrected. IR spectra
4.3 | Syntheses of complexes
4.3.1 | Synthesis of complex 1
A methanolic solution (3 ml) of Co(OAc) ⋅4H O (3.48 mg,
2
2
0.01 mmol) was gradually added to a chloroform solution
1
(2 ml) of H L (6.16 mg, 0.01 mmol). A bright brown
2

KANG ET AL.
13 of 15
66]
[
solution was obtained. The reaction solution was stirred
for 10 min at room temperature. Several brown needle‐
like single crystals suitable for X‐ray analysis were
obtained by slow evaporation of the maternal solution
in a bottle after one week. They were separated and
washed several times with cold methanol and dried in
vacuo. Yield: 58.3%. Anal. calcd for C H CoN O (%):
solved using the direct method with SHELXS‐2014.
All hydrogen atoms were added theoretically and
difference‐Fourier map exhibited the positions of the
remaining atoms. The hydrogen atoms were placed in
idealized positions and constrained to ride on their parent
atoms. All the non‐hydrogen atoms were refined with
independent anisotropic displacement parameters using
38
38
6 6
2
C, 62.21; H, 5.22; N, 11.45; Co, 8.03. Found (%): C,
1.87; H, 5.54; N, 11.59; Co, 7.89.
a full‐matrix least‐squares procedure on
F
with
[
67]
6
SHELXL‐2014.
The crystal data and experimental
parameters relevant to the structure determinations are
listed in Table 1.
4.3.2 | Synthesis of complex 2
ACKNOWLEDGEMENTS
A solution of Zn(NO ) ⋅6H O (2.97 mg, 0.010 mmol) in
methanol (2 ml) was added to a solution of ligand H2L
3
2
2
2
This work was supported by the National Natural Science
Foundation of China (21761018) and the Program for
Excellent Team of Scientific Research in Lanzhou
Jiaotong University (201706), both of which are gratefully
acknowledged.
(6.26 mg, 0.010 mmol) in methanol (2 ml). The mixed
solution was kept stirring for 10 min, and gently heated
to 60°C, the color of the mixed solution gradually clarify-
ing. After cooling to room temperature and then filtering,
the filtrate was allowed to stand for a few days in the dark
at room temperature. Colorless block‐shaped single crys-
tals suitable for X‐ray diffraction measurements were
formed at the bottom of the bottle after a few days on
slow evaporation of solvent. Yield: 50.8%. Anal. calcd for
C114H114N Zn O (%): C, 61.67; H, 5.18; N, 11.35; Zn,
SUPPLEMENTARY MATERIAL
CCDC 1890720–1890722 contain the supplementary crys-
tallographic data for complexes 1, 2 and 3. These data can
be obtained free of charge via http://www.ccdc.cam.ac.
uk/conts/retrieving.html, or from the Cambridge Crystal-
lographic Data Centre, 12 Union Road, Cambridge CB2
1EZ, UK; fax: (+44) 1223 336 033; or e‐mail:
deposit@ccdc.cam.ac.uk.
18
3 18
8
.83. Found (%): C, 61.45; H, 5.33; N, 11.19; Zn, 8.94.
4.3.3 | Synthesis of complex 3
A methanol solution (2 ml) of Cu(OAc) ⋅2H O (1.99 mg,
2
2
0
.01 mmol) was added to a chloroform solution (3 ml)
2
ORCID
of ligand H L (6.26 mg, 0.01 mmol), and the color of
2
the mixed solution immediately turned brown. The reac-
tion solution was stirred for 10 min at room temperature,
and the mixture solution was filtered and the filtrate was
allowed to stand for a few days in the dark. Several
brown needle‐like single crystals suitable for X‐ray analy-
sis were obtained by slow evaporation of the maternal
solution in the bottle. Yield: 53.7%. Anal. calcd for
C150H130Cl Cu N O (%): C, 60.22; H, 4.38; N, 11.24;
Wen‐Kui Dong https://orcid.org/0000-0003-1249-5808
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4

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How to cite this article: Kang Q‐P, Li X‐Y, Wang
L, Zhang Y, Dong W‐K. Containing‐PMBP N O ‐
donors transition metal(II) complexes: Synthesis,
crystal structure, Hirshfeld surface analyses and
fluorescence properties. Appl Organometal Chem.
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crystal structures, University of Göttingen, Germany, 2014.
2
2
SUPPORTING INFORMATION
2019;e5013. https://doi.org/10.1002/aoc.5013
Additional supporting information may be found online
in the Supporting Information section at the end of the
article.