Polymorphism and configurational isomerism in 3-(9-anthryl)-1-(3-hydroxyphenyl)prop-2-en-1-one

Article abstract of DOI:10.1016/j.molstruc.2019.03.049

In this study, 3-(9-anthryl)-1-(3-hydroxyphenyl)prop-2-en-1-one was synthesized and formed two cis isomers (α and β polymorphs) and one trans isomer under different crystallization conditions. Single crystal X-ray diffraction revealed that all the three c

Full text of DOI:10.1016/j.molstruc.2019.03.049

Accepted Manuscript
Polymorphism and configurational isomerism in 3-(9-anthryl)-1-(3-
hydroxyphenyl)prop-2-en-1-one
Qi Feng, Jiali Wang, Wenhui Huan, Chao Shen, Fang Guo, Jiadan Lu, Guowang Diao
PII:
S0022-2860(19)30325-4
DOI:
https://doi.org/10.1016/j.molstruc.2019.03.049
MOLSTR 26318
Reference:
To appear in: Journal of Molecular Structure
Received Date: 12 October 2018
Revised Date: 14 March 2019
Accepted Date: 15 March 2019
Please cite this article as: Q. Feng, J. Wang, W. Huan, C. Shen, F. Guo, J. Lu, G. Diao, Polymorphism
and configurational isomerism in 3-(9-anthryl)-1-(3-hydroxyphenyl)prop-2-en-1-one, Journal of Molecular
Structure (2019), doi: https://doi.org/10.1016/j.molstruc.2019.03.049.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to
our customers we are providing this early version of the manuscript. The manuscript will undergo
copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please
note that during the production process errors may be discovered which could affect the content, and all
legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT
1
2
3
4
5
6
7
Polymorphism and configurational isomerism in 3-(9-anthryl)-1-(3-
hydroxyphenyl)prop-2-en-1-one
a
a
a
a
a
a
a
8
9
Qi Feng, Jiali Wang, Wenhui Huan, Chao Shen, Fang Guo, Jiadan Lu, Guowang Diao*
a
School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou, 225002
1
0
1
1
Abstract
1
2
1
1
1
1
1
1
1
2
2
2
2
2
3
4
5
6
7
8
9
0
1
2
3
4
In this study, 3-(9-anthryl)-1-(3-hydroxyphenyl)prop-2-en-1-one was synthesized and formed two cis
isomers (α and β polymorphs) and one trans isomer under different crystallization conditions. Single
crystal X-ray diffraction revealed that all the three crystals exhibit the similar crystal structures, in
which the two adjacent chalcone molecules form dimers through intermolecular H-bonds between
the phenolic hydroxyl and carbonyl groups, and all of the dimers stack parallel to construct their 3D
structures. In order to rationalize the configurational phenomenon and investigate the stability of the
three crystals, Hirshfeld surface analyses, theoretical calculation and grinding experiments were
performed. The results revealed that the coexistence of H-bonds and C-H···π interactions around the
two hydrogen atoms on the C=C double bond may be crucial for formation of the cis configuration,
and the trans isomer is more stable than the other two cis isomers. Moreover, the optical-physical
properties of these crystals were also investigated. Due to the similar crystal structures, the similar
fluorescence bands were observed in their spectra.
2
2
2
5
8
9
Keywords: configurational isomerism, chalcone, polymorphism
2
67
3
0
Introduction
3
3
3
1
2
3
Cis–trans isomerism of organic compounds, also known as geometric isomerism or configurational isomerism, is
always a subject of great interest from both academia and industry, for their distinctive physical and chemical
properties, such as solubility, stability and mechanical properties (tabletability), etc [1-6].
3
3
3
3
4
5
6
7
The importance of cis–trans isomerism in luminescent material system was also underscored, because the different
configuration of a given molecule usually exhibits distinct optical-physical properties [7,8]. For example, 5-(-1-(4-
bromo-phenyl)-3a’,7a’-hexahydro-1H-indazol-3-yl)-3-methyl-1-phenyl-1H-pyrazole-4-carbonitrile (PZ) displays an
emission band at 396 nm in trans form, whereas its fluorescence emission maximum is 475 nm in cis form [9].
3
3
4
4
4
4
4
4
4
4
8
9
0
1
2
3
4
5
6
7
Chalcone [10], an important natural compounds possessing a wide range of bioactivities [11], can be also used as
organic luminescent materials due to their excellent optical-physical properties [12,13]. In this study, an chalcone
derivative, 3-(anthracen-9-yl)-1-(3-hydroxyphenyl)prop-2-en-1-one (Scheme 1), was synthesized and some
interesting solid state behaviors have been observed. The compound afforded three different crystals from a variety
of different solvents. Single crystal X-ray analyses revealed that two of them adopt the cis configuration and only
one exhibits a trans configuration. The trans isomer crystallizes in a monoclinic system with space group C2/c, and
its asymmetric units (ASU) accommodates one crystallographically independent molecule. However, both the two
cis isomers (named as α and β polymorphs) crystallize in the triclinic system with space group Pī, and their ASUs
accommodate two and one crystallographically independent molecules, respectively. To the best of our knowledge,
for the chalcone derivative, the trans isomers usually exhibit greater stability than the cis isomers, and many

ACCEPTED MANUSCRIPT
4
4
5
5
5
5
8
9
0
1
2
3
chalcones in the previous reports, such as 3-(1-pyrenyl)-1-(4-chlorophenyl)prop-2-en-1-one, 1-phenyl-3-(1-
pyrenyl)prop-2-en-1-one and 4-bromo-1-naphthyl Chalcone, mainly adopt trans configuration due to their strikingly
steric effect and stabilities [14,15]. Conformational polymorphism was rarely reported for the cis chalcone
molecules, even rarer an ASU accommodates two cis conformers simultaneously [16]. Based on the three crystal
structures, computational methods were performed for rationalizing the configuration phenomenon and investigating
their stability. Meanwhile, the solid-state properties of the three crystals were also investigated.
5
5
4
5
Scheme 1. Chemical structure of 3-(anthracen-9-yl)-1-(3-hydroxyphenyl)prop-2-en-1-one.
5
5
6
7
Experiment
Material Synthesis and Characterization
5
5
6
6
6
6
6
6
8
9
0
1
2
3
4
5
The chalcone molecule was synthesized and characterized by a previous reported method [18]. A mixture of 3-
hydroxyacetophenone (1.6 g), 9-anthracenecarboxaldehyde (2.3 g), and 3 M of aqueous sodium hydroxide (6 mL) in
ethanol (20 mL) was stirred at 50°C for 16 h. The crude product was collected by filtration and recrystallized from
1
95% ethanol to give pure chalcone (trans isomer) as orange crystals: 2.71 g, yield: 74.9%, mp: 198-200 °C. H
NMR (DMSO, Figure 1S of the Supporting Information): δ (ppm) 7.03−7.08 (dd, 1H), 7.32−7.38 (t, 1H), 7.46−7.49
1
3
(t, 1H), 7.53−7.64 (m, 6H), 8.10−8.17 (dd, 2H), 8.21−8.28 (d, 2H), 8.55−8.62 (d, 1H), 8.67 (s, 1H), 9.83(s, 1H).
C
NMR (DMSO, Figure 2S): δ (ppm) 115.13, 120.18, 121.00, 125.44, 126.05, 127.25, 128.70, 129.32, 129.43, 130.14,
130.47, 131.29, 131.85, 139.10, 140.59, 158.23, 189.13.
6
6
Crystals’ Preparation
6
6
6
7
7
7
8
9
0
1
The preparation of the trans isomer crystals has been mentioned in the synthesis part. α polymorph of the cis
isomers was recrystallized from ethanol/chloroform mixed solvent (v : v = 1 : 3). Slow evaporation of the solvent at
room temperature for 4–5 days yielded orange needlelike crystals. However, despite extensive efforts, β polymorph
of the cis isomers was obtained only once from acetone/dichloromethane (v : v = 1 : 1) mixed solvent. Since it was
difficult to get an adequate amount of β polymorph, only its single crystal data was measured.
7
2
Measurement
7
7
7
7
7
7
7
8
8
3
4
5
6
7
8
9
0
1
Single crystal X-ray diffraction experiments were carried out using a Bruker D8 QUEST diffractometer equipped
with a Bruker APEX-II (λ = 0.71073 Å). Data collection for the three crystals was done at ambient temperature.
Crystal structures were solved with direct methods using SHELXL-2014 program and refined anisotropically using
a full-matrix least-squares procedure [19]. All non-hydrogen atoms were refined anisotropically. All the hydrogen
atoms, including hydrogen atom of the phenolic hydroxyl groups, were inserted at their calculated positions and
fixed at their positions. The structural data for three crystals have been deposited as CIFs at the Cambridge
Crystallographic Data Base (CCDC No. 1868346, 1855435 and 1868347) and are also available as Supporting
Information (SI). Powder X-ray diffraction (PXRD) patterns were measured with a Bruker D8 advance superspeed
powder diffractometer, which operated at ambient temperature, using Cu Kα radiation (λ = 0.15405 nm).
8
8
8
2
3
4
UV-Vis absorption spectra were recorded on a Shimadzu UV-3600 spectrometer. Fluorescence spectra were
obtained on a Horiba FluoroMax 4 spectrofluorometer. Quantum yields of the chalcone in different solvents
were also determined on Horiba FluoroMax 4 spectrofluorometer, quinolone sulfate in 0.5 M H SO was used as a
2
4

ACCEPTED MANUSCRIPT
8
8
5
6
standard and excitation was chosen at 365 nm. Solid fluorescent quantum yields were obtained by using an
Edinburgh Instrument with an excitation wavelength at 365 nm.
8
7
Hirshfeld surface analysis
8
8
8
9
Hirshfeld surface graphical representation over dnorm around each crystallographically independent molecule in the
three polymorphs, and associated 2D fingerprint plots were performed out by using Crystal Explorer 3.1 [20].
9
9
0
1
Calculation Details
Comparison of crystals’ stability
9
9
9
9
9
9
2
3
4
5
6
7
The geometry optimization of crystals was performed starting from the X-ray structures. Cambridge Sequential
Total Energy Package (CASTEP) module based on the Planewaves Pseudopotential method of density functional
theory (DFT) was used to optimize three crystals, and the most stable structures and energy are calculated.
Generalized Gradient Approximation (GGA) and Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional
were used. To ensure the correctness of the calculation, the cut-off energy was selected as 400.0 eV. All the
calculations were performed by Material Studio 6.0 program [21].
9
9
8
9
Theoretical study of spectra
Structural, electronic and optical properties were studied in the framework of the density functional theory (DFT).
The M062X functional with 6-31+G (d,p) basis set level was chosen to calculate excited state [22]. All calculations
were performed using the Gaussian 09 version B.01 suite of programs [23]. The absence of imaginary frequency
modes for the optimized structures at the DFT level confirms a true minimum on the potential energy surface.
Further analyses of electronic and optical properties were performed by calculations of both vertical and adiabatic
ionization potentials and the calculation of the visible-UV absorption and emission spectra in the framework of
time-dependent DFT (TD-DFT).
1
1
1
1
1
1
00
01
02
03
04
05
1
06
07
Result and Discussion
Crystal structure
1
108
109
110
111
112
113
Single crystal X-ray diffraction analyses were performed for the three crystals to determine their structures. Thermal
ellipsoids of the chalcone molecules in the three ASUs were shown in Figure 1. It was worth noting that all the cis
isomers exhibit the similar conformation with each other, in which the dihedral angles between the anthracene and
benzene rings are 80.07° (type A in α polymorph), 83.08° (type B in α polymorph) and 82.43° (β polymorph),
respectively (Figure 2). In contrast, the trans isomer shows a nearly planar structure with the dihedral angle of
29.95°. The crystallographic data was presented in Table 1.

ACCEPTED MANUSCRIPT
1
14
15
1
Figure 1. Thermal ellipsoids plots of the two cis isomers (a and b) and trans isomer (c).
1
1
16
17
Figure 2. Comparison of the conformation for the three cis isomers.
118
Table 1. Numerical details of the solutions and refinements of the three crystal structures.
Crystals
Formula
Morphology
Crystal system
Space group
a / Å
α
polymorph
C23 H16 O2
needle
β
polymorph
C23 H16 O2
needle
trans isomer
C23 H16 O2
needle
triclinic
triclinic
Pī
monoclinic
C2/c
Pī
5.4651(6)
16.891(2)
19.743(3)
68.888(4)
89.737(4)
5.4587(6)
33.809(4)
5.5199(7)
21.394(2)
90
b / Å
11.5366(14)
13.5526(16)
96.297(4)
c / Å
α /deg
β /deg
96.784(4)
124.694(2)

ACCEPTED MANUSCRIPT
γ /deg
89.614(4)
1700.2(4)
4
90.865(4)
842.04(17)
2
90
3282.8(7)
8
3
V/ Å
Z
-3
ρ (calcd)/Mg m
1.267
1.279
1.313
θ Range for data
collection/°
2
.418–27.581 1.523–27.576 2.316–27.548
F(000)
680
340
1360
0
0
0
0
.0571,
0.0601,
0.1490
0.1057,
0.1679
R
1
, w R
2
(I > 2σ(I))
0.0577, 0.1132
0.1735, 0.1424
.1464
.1211,
.1794
R , w R (all data)
1
2
Goodness-of-fit
CCDC
1.002
1.098
1.068
1868346
1855435
1868347
119
120
121
122
123
124
125
126
127
128
129
It was interesting that the three crystals have the similar structures. As shown in Figures 3−5, due to the
intermolecular H-bonds (O-H···O, summarized in Table 2) between the phenolic hydroxyl and carbonyl groups, the
chalcone molecules in all the three crystals pair up and generate the molecular dimers. In the β polymorph and trans
isomer, the molecular dimers are parallel stacked along the a, b and c axes to give their 3D structures. The analogous
structure could be found in the monoclinic polymorph of 1-phenyl-3-(3-hydroxyphenyl)-2-propen-1-one, where the
molecular dimer constructed via H-bonds (O-H···O) is also the repeating motif [24]. Compared with above two
crystals, the α polymorph possesses two types of chalcone molecules, namely types A and B. In this crystal, the two
adjacent chalcone molecules connect with each other and form A-A or B-B dimers. These dimers are stacked
alternately along the c axis and adopt parallel arrangement along the a and b axes to provide its 3D structure.
Furthermore, in the three crystals, the closest centroid distances between the anthracene rings is 5.459 Å, thus no
strong π-overlap exist among them.
130
131
132
133
Figure 3. Crystal structure of α polymorph. (a) The two types of the hydrogen bonding dimers. (b) 3D packing diagram of α
polymorph projected in the bc plane. The types of A and B chalcone molecules are shown in purple and green, respectively.
Hydrogen atoms not participating in the interactions have been omitted for clarity.

ACCEPTED MANUSCRIPT
134
1
35
36
Figure 4. Crystal structure of β polymorph. (a) The hydrogen bonding dimer. (b) 3D packing diagram of β polymorph projected
in the bc plane. Hydrogen atoms not participating in the interactions have been omitted for clarity.
1
137
1
38
39
Figure 5. Crystal structure of the trans isomer. (a) The hydrogen bonding dimer. (b) 3D packing diagram of the trans isomer
projected in the ac plane. Hydrogen atoms not participating in the interactions have been omitted for clarity.
1
140
Table 2. H-bonds geometry (Å, deg) in the three crystals.
Crystals
D-X···A
D-X
0.82
0.82
0.82
0.82
X···A
2.14
2.09
2.10
2.07
D···A
D-X···A
159.2
O1–H16···O2
O4–H32···O3
2.916(2)
α
β
polymorph
2.900(2)
169.3
polymorph O1–H16···O2
O1–H1···O2
2.8973(19)
2.8637(18)
163.3
trans isomer
162.0
141
Powder X-ray Diffraction (PXRD) Patterns and FT-IR Spectroscopy
142
143
144
As shown in Figure 6, PXRD patterns of α polymorph and trans isomer are distinctly different and are in agreement
with that simulated from their crystal data. Thus, the powder product could be used for the solid-state properties
investigation later.

ACCEPTED MANUSCRIPT
1
45
46
1
Figure 6. Comparison of the experimental and simulated PXRD patterns of the α polymorph (a and c) and trans isomer (b and d).
FT-IR spectra were also recorded to identify the cis and trans isomers. From the fingerprint spectra, the two peaks
147
148
149
150
151
−1
with medium intensity at 773 and 993 cm could be observed in their fingerprint areas (Figure 7a, the entire spectra
−1
were shown in Figure 3S), corresponding to the two peaks at 793 and 1039 cm , which were calculated in ideal gas
phase conditions (Figure 7b). The two peaks are specific for the nonplanar deformation vibrations of the hydrogens
of an ethylenic bond in the cis or trans isomer, suggesting that the opposite configuration between the two crystals.
1
52
53
1
Figure 7. The experimental and simulated fingerprint spectra of α polymorph (a) and trans isomer (b).
154
Configuration and stability analyses of 3-(9-anthryl)-1-(3-hydroxyphenyl)prop-2-en-1-one

ACCEPTED MANUSCRIPT
155
156
157
In contrast to many other chalcone molecules exhibiting the trans configuration, the chalcone in this study mainly
exhibits the cis configuration. Aiming to rationalize the configurational phenomenon of this chalcone, computational
methods were performed.
158
159
160
161
First, Hirshfeld surface was performed to give insights regarding the important intermolecular interactions in the
three crystals. The inspection of the intermolecular interactions was normalized by van der Waals radii through a
red-white-blue color scheme, where the red spots denote closer contacts of molecules. The non-covalent interactions
occurring within the structures have clear signatures on the fingerprint plots.
1
62
63
1
Figure 8. Hirshfeld surface mapped with dnorm for the four independent molecules in the three crystals.
164
165
166
167
168
169
170
171
172
173
174
175
176
From the Hirshfeld surface (Figure 8), it was obviously observed that all the four chalcone molecules exhibit two red
spots on the phenolic hydroxyl and carbonyl groups, corresponding to the H-bonds (O-H···O) for constructing the
molecular dimers. That is to say, these H-bonds play a key role in crystal packing for the three crystals. In addition,
for each molecule in α and β polymorphs, another two red spots could be found around the hydrogen atoms on C=C
double bond (one red spot on type A molecule in α polymorph is not very obvious), which should be ascribed to the
interactions among the 1D chain motifs in crystal structures (Table 3). Take type A molecule for example (Figure 9),
one spot should be assigned to the weak H-bond (C=O···H) associated with carbonyl group from the neighboring
chalcone molecule, another spot could be assigned to intermolecular C-H···π interaction. However, for the trans
chalcone, only one red spot corresponding to the intermolecular H-bond (C=O···H) was observed around C=C
double bond. Based on the Hirshfeld surface analyses, a conclusion could be drawn that the coexistence of H-bond
(C=O···H) and C-H···π interactions around C=C double bond are crucial for formation of the cis isomer, which like
two hands pull the two hydrogen atoms to the same side of C=C double bond. In contrast, disappearance of one
interaction would result in formation of the trans chalcone configuration.

ACCEPTED MANUSCRIPT
1
77
78
1
Figure 9. H-bond (C=O···H) and C-H···π interaction around the hydrogen atoms on C=C double bond.
Table 3. Weak H-bonds and C-H···π interactions geometry (Å, deg) in the three crystals.
179
Crystals
D-X···A
D-X
X···A
2.670
2.673
2.517
2.877
2.465
2.857
2.608
D···A
3.434
3.566
3.353
3.802
3.331
3.766
3.486
D-X···A
139.91
161.20
149.67
173.34
148.50
166.22
157.78
C16–H11···O2
C15–H10···π
C39–H27···O3
C38–H26···π
C16–H11···O2
C15–H10···π
C16–H16···O2
0.930
0.819
0.930
0.929
0.971
0.930
0.930
α
polymorph
β
polymorph
trans isomer
180
181
182
183
184
185
Table 4 summarized the contacts contributing to the Hirshfeld surface represented in normal mode. It was found that
weak H···H contacts display the major contribution in all the three polymorphs, with 44.2%, 41.9%, 43.8% and 43.0%
of total surface area, respectively. The C···H contacts with second major contribution comprise 38.2%, 40.1%, 38.2%
and 37.1% of total surface area. Apart from that, O···H contacts in the three polymorphs also show important
contribution for the supramolecular architectures from 12.3 to 14.6% of total surface area and appear as two wings
in the left (H···O) and right (O···H) areas of the related plots (Figure 10).

ACCEPTED MANUSCRIPT
186
1
1
87
88
Figure 10. Two-dimensional fingerprint plots for O···H / H···O contacts: types A (a) and B (b) in α polymorph, β polymorph (c)
and trans isomer (d).
189
Table 4. Contributions of the intermolecular contacts.
Chalcone molecule
polymorph (type A)
polymorph (type B)
H
···H %
C
···H %
38.2
O
···H %
14.3
C
···C %
C
···O %
1.1
α
α
44.2
2.3
41.9
40.1
14.6
1.8
1.7
β
polymorph
43.8
38.2
14.3
2.5
1.3
trans isomer
43.0
37.1
12.3
5.2
2.4
190
191
192
193
194
Second, according to former research, the most chalcone molecules contained large π-conjugated groups, such as
anthryl or pyrenyl, usually exhibit twisted structure [25,26]. However, in our system, the dihedral angles between
the anthracene and benzene rings in all the cis isomers are nearly vertical. In contrast, the trans chalcone molecule
shows a nearly planar structure. In order to investigate stability of the three crystals, theoretical calculation and
correlative phase transition experiments were performed.
195
196
197
198
199
200
Calculation details has been described in experiment part. Fixed the unit cell parameters, the molecules were relaxed
to obtain the energy of each unit cell, and the result was summarized in Table 5. It could be found that the trans
isomer exhibits lowest energy of 4690.19 eV, which has 0.18 and 0.1eV lower than α and β polymorphs, suggesting
it is more stable than the other two cis polymorphs. Moreover, as shown in Figure 11, the conversion energy barrier
from cis isomer to trans isomer was also calculated by DFT in gas phase condition at M062X/6-31+G(d,p) level.
The cis isomer need to overcome 181.453 kcal/mol for transforming into trans isomer.

ACCEPTED MANUSCRIPT
201
202
203
204
In order to verify the above result, the phase transitions were investigated. Analysis of the grinding product by
PXRD patterns (Figure 5S), whether or not the solvent was added, the α polymorph always transformed into the
trans ismoer polymorph. This result further proved that the trans isomer is more stable, which may be also
responsible for unavailability of β polymorph, despite extensive efforts.
205
Table 5. The energy (eV) of the three polymorphs calculated by GGA-PBE method (cut-off energy 400.0 eV) [27].
[a]
Optimized crystal structure
energy
α
polymorph
-4690.01
-4690.09
-4690.19
β polymorph
trans isomer
[
a]
206
Optimized super cell were shown in Figure 4S.
2
2
07
08
Figure 11. Conversion energy barrier from cis isomer to trans isomer.
209
210
211
212
213
214
215
Optical–physical properties
The absorption and fluorescence spectra of the chalcone in various solvents with different polarities were shown in
Figure 12. The absorption spectra show very little change with an increase in the solvent polarity and exhibit the
narrow absorption bands with the absorption maxima around 250 nm. Besides, several weak absorption bands in
340–420 nm could be also observed, which are attributed to anthracene chromophore [28]. Agreeing with the above
experiments, TD-DFT calculation revealed that the chalcone molecule (trans isomer) has two dominant absorption
bands (Figure 13a). The one band was found at 5.10 eV (243 nm), which is associated with HOMO-2→LUMO
216
217
218
219
220
221
222
transition. The other band is around 3.24 eV (383 nm), corresponding to HOMO→LUMO transition.
In Figure 12b, the fluorescence spectra in various solvents were presented. Compared with the absorption spectra,
the intensity of fluorescence peaks exhibits obvious change with an increase in the polarity of solvents. When the
solvent was changed from chloroform to acetonitrile, fluorescence intensity decrease / increase could be found
around 280–330 and 360–460 nm in the spectra, respectively. The spectrum of the chalcone in acetonitrile shows
vibration peaks at 393, 415 and 438 nm, corresponding to anthracene chromophore emission [28]. However, when
measured in the other solvents, the vibration structure is less clear, even disappears almost completely in ethanol.

ACCEPTED MANUSCRIPT
223
224
225
226
The emission spectrum of the chalcone molecule (trans isomer) in gas phase calculated at the M062X/6-31+G(d,p)
level of theory were plotted with respect to the integrated amplitude and were shown Figure 13b. It could be
observed that the dominant emission bands are centered at 3.10 eV (404 nm) and 4.03 eV(308 nm), which are
attributed to the LUMO→HOMO and LUMO+2→HOMO transitions, respectively.
2
27
28
2
Figure 12. UV-Vis (a) and fluorescence (b) spectra of the chalcone in various solvents.
2
2
29
30
Figure 13. UV-Vis (a) and fluorescence (b) spectra of the chalcone calculated in gas phase at M062X/6-31+G(d, p).
Apart from that, the optical-physical properties of α polymorph and trans isomer were also investigated. As shown
in Figure 14, the α polymorph and trans isomer have similar absorption spectra, which exhibit a two broad
absorption bands around 245 and 300 nm, respectively. Compared with that measured in solvents, the absorption
bands in 340–420 nm range almost disappear.
231
232
233
234
235
236
237
238
239
Excited at 365 nm, the weak fluorescence could be observed in both the α polymorph and trans isomer in our system,
they exhibit a broad band with only one peak centered at 592 and 586 nm, respectively. Compared with that
measured in solvents, the solid-state emission maxima shift to the longer wavelength region with a red shift of about
160 nm. The solid-state properties of a given molecule are usually closely related to its arrangement. Thus, the
similar optical-physical properties of the two crystals should be ascribed to their similar crystal structures.

ACCEPTED MANUSCRIPT
2
40
41
2
Figure 14. Absorption (a) and fluorescence (b) spectra of the α polymorph and trans isomer.
Table 6. Optical-Physical Properties Data.
242
[a]
[b]
[c]
solvents / crystals
ethanol
λab (nm)
λem (nm)
ΦF
2
2
52
54
377
0.003
0.002
chloroform
ethyl acetate
acetonitrile
α polymorph
291
292
251
250
249
309
0.002
0.001
0.003
0.002
394
592
586
trans isomer
a
b
2
43
44
Maximum wavelengths of absorption spectra. Wavelengths of fluorescence emission spectra excited at 365 nm for the chalcone in
c
2
solvents or crystals. Fluorescent quantum yields excited at 365 nm.
245
Conclusions
246
247
248
249
250
251
252
253
254
255
In summary, we discovered an interesting polymorphism in 3-(9-anthryl)-1-(3-hydroxyphenyl)prop-2-en-1-one.The
compound formed three crystals, two of them adopt the cis configuration and only one exhibits the trans
configuration. All the three crystals exhibit the similar structures, in which the two adjacent chalcone molecules
form the dimers and stack parallel to construct their crystal structures. Hirshfeld surface analyses revealed that the
intermolecular H-bonds (O-H···O) between the phenolic hydroxyl and carbonyl groups play a key role in crystal
packing for the three crystals. However, the coexistence of H-bonds (C=O···H) and C-H···π interactions around
C=C double bond are crucial for formation of the cis configuration. Moreover, the theoretical calculation and
grinding experiments revealed that the trans isomer is more stable than the two other cis isomers. The optical-
physical properties of the α polymorph and trans isomer were also investigated. Due to their similar crystal
structures, no obvious change could be found in their fluorescence spectra.
2
56
57
Conflicts of interest
2
There are no conflicts to declare.
258
Acknowledgements
259
260
261
This work is partly supported by the National Natural Science Foundation of China (Grant No. 21773203), Certificate of China
Postdoctoral Science Foundation Grant (No. 2018M632387), the Natural Science Foundation of the Jiangsu Higher Education
Institutions of China (No. 18KJB150035), and Innovation and Cultivation Fund of Yangzhou University (No. 2017CXJ012).

ACCEPTED MANUSCRIPT
262
Notes and references
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
1
2
3
4
5
6
Zhao, Y.; Shen, X. F.; He, S. L; Han, X. G.; Ni, Z. H. SYNTHETIC MET. 2018, 245, 175–1181.
Dey, D.; Chopra, D CrtstEngComm 2015, 17, 5288–5298.
Swapna, B.; Suresh, K.; Nangia, A. Chem.Commun. 2016, 52, 4037–4040.
Hodges, J. M.; Schaak, R. E. Accounts Chem. Res. 2017, 50, 1433–1440.
Klein, C.; Fischer, C.; Seichter, W.; Schwarzer, A.; Weber, E. CrtstEngComm. 2011, 13, 1931–1938.
Couzijn, EPA.; Schakel, M; de Kanter, FJJ; Ehlers, AW; Lutz, M; Spek, AL; Lammertsma, K. Angew. Chem. Int. Edit.
2004, 43, 3440–3442.
Geng, J.; Tao, T.; Chen, H. Q.; Huang, W. Inorg. Chem. Commun. 2014, 42, 23–28.
Li, J. T.; Luo, X. L.; Zhou, Y.; Zhang, L. R.; Huo, Q. S.; Liu, Y. L. Cryst. Grow. Des. 2018, 18, 1857–1863.
Mati, S. S.; Sarkar, S.; Sarkar, P.; Bhattacharya, S. C. J. Phys. Chem. A. 2012, 116, 10371–10382.
.
.
7
8
9
10 Go, M. L.; Wu, X.; Liu, L. X. Curr. Med. Chem. 2005, 12, 483–499.
11 Labib, M. B.; Sharkawi, S. M. Z.; El-Daly, M. Bioorg. Chem. 2018, 80, 70–80.
12 Cheng, X.; Wang, Z. Y.; Tang, B. L.; Zhang, H. Y.; Qin, A. J.; Sun, J. Z.; Tang, B. Z. Adv. Funct. Mater. 2018, 28
1706506.
13 Karuppusamy, A.; Vandana, T.; Kannan, P. J. Photoch. Photobio. A. 2017, 345, 11–20.
14 Zhang, R. M.; Wang, M. L.; Sun, H.; Khan, A.; Usman, R.; Wang, S. Z.; Gu, X. T.; Wang J.; Chun, C. X. New J.
,
Chem. 2016, 44, 6441–6450.
15 Nithya, R.; Santhanamoorthi, N.; Kolandaivel P.; Senthilkumar, K. J. Phys. Chem. A. 2011, 115, 6594–6602.
16 Ramos, R. R.; da Silva, C. C.; Guimaraes, F. F.; Martins, F. T. CrtstEngComm. 2016, 18, 2144–2154.
17 James, J. P.; Bhat, K. I.; More, U. A.; Joshi, S. D. Med. Chem. Res. 2018, 27, 546–559.
18 Sheldrick, G. M. Acta Crystallogr. 2015, C71, 3.
19 Wolff, S. K.; Grimwood D. J.; McKinnon J. J.; Jayatilaka D.; Spackman M. A. CrystalExplorer 3.1, The University of
Western Australia, Perth, Australia, 2012.
20 Rajan, R.; Ravindran, T. R.; Venkatesan, V.; Srihari, V.; Pandey, K. K.; Chandra, S.; Mishra, K. K.; Vargeese, A. A. J.
Phys. Chem. A. 2018, 122, 6236–6242.
21 Jennings, G.; Smith, M. D.; Kuang, S. M.; Hodges, L. M.; Tyrell, J.; Williamson, R. T.; Seaton, P. J. Chem.
Crystallogr. 2012, 42, 159–164.
22 Pandeti, S.; Feketeova, L.; Reddy, T. J.; Abdoul-Carime, H.; Farizon, B.; Farizon, M.; Mark, T. D. J. Chem. Phys
.
2019, 150, 014302.
23 Koraiem, A. I.; El-Shafei, A.; Abdellah, I. M.; Abdel-Latif, F. F.; Abd El-Aal, R. M. J. Mol. Struct. 2018, 1173, 406–
416.
24 McKinnon, J. J.; Spackman, M. A.; Mitchell, A. S. Acta Crystallogr. 2004, B60, 627–668.
25 Yu, F. F.; Wang, M. L.; Sun, H.; Shan, Y. Q.; Du, M.; Khan, A.; Usman, R.; Zhang, W.; Shan, H. B.; Xu, C. X. RSC
Adv. 2017, 7, 8491-8503.
26 Zhang, R. M.; Wang, M. L.; Sun, H.; Khan, A.; Usman, R.; Wang, S. Z.; Gu, X. T.; Wang J.; Chun, C. X. New J.
Chem. 2016, 44, 6441–6450.
27 Nisar, J.; Arhammar, C.; Jamstorp, E.; Ahuja, R. Phys. Rev. B. 2011, 84, 075120.
28 Hanulia,
T.;
Inami,
W.;
Ono,
A.;
Kawata,
Y.
Opt.
Commun.
2018,
427
,
266–270.

ACCEPTED MANUSCRIPT
Dear Referees:
We would like to submit the manuscript entitled “Polymorphism and configurational isomerism in
3
-(9-anthryl)-1-(3-hydroxyphenyl)prop-2-en-1-one” to be published in Journal of Molecular
Structure. Chalcone have been studied extensively, however, the most chalcone molecules exhibit
the trans configuration. In this work, an chalcone,
3
-(anthracen-9-yl)-1-(3-hydroxyphenyl)prop-2-en-1-one, was synthesized, which afforded three
polymorphs under different solvents. To our surprise, two of the three polymorphs exhibit the cis
configuration, whereas only one exhibit the trans configuration. Hirshfeld surface analyses and
theoretical calculation were performed for rationalizing the configuration polymorphism
phenomenon and investigating the stability of these crystals. The results revealed that the
coexistence of H-bonds and C-H···π interactions around the two hydrogen atoms on the C=C
double bond may be crucial for formation of the cis configuration, and the trans polymorph is
more stable than the two other cis polymorphs. Meanwhile, several solid-state properties were
also investigated. We believed that the study could provide reference for controlling the
polymorphism and configuration in chalcone derivatives. We also deeply appreciate your
consideration of our manuscript, and look forward to receiving comments from the reviewers. If
you have any queries, please don’t hesitate to contact us at the address below.
Thank you and best regards.
Yours sincerely,
Corresponding author:
Name: Guowang Diao
E-mail: gwdiao@yzu.edu.cn