Synthesis and characterization of p-benzophenoneoxycarbonylphenyl acrylate by means of experimental measurements and theoretical approaches, and bulk melt polymerization

Article abstract of DOI:10.1016/j.molstruc.2013.07.003

This multidisciplinary study deals with not only the synthesis of p-benzophenoneoxycarbonylphenyl acrylate (BPOCPA) in the xylene solvent and production of Poly(BPOCPA) by bulk melt polymerization and solution methods but also the characterization of BPOC

Full text of DOI:10.1016/j.molstruc.2013.07.003

Journal of Molecular Structure 1049 (2013) 479–487
Contents lists available at SciVerse ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Synthesis and characterization of p-benzophenoneoxycarbonylphenyl
acrylate by means of experimental measurements and theoretical
approaches, and bulk melt polymerization
c
b
d
b
U. Soykan a, S. Cetin a, B. Ozturk a, F. Karaboga b, , Y. Zalaoglu , M. Dogruer , G. Yildirim , C. Terzioglu
⇑
a Abant Izzet Baysal University, Department of Chemistry, Bolu 14280, Turkey
b Abant Izzet Baysal University, Department of Physics, Bolu 14280, Turkey
c Osmaniye Korkut Ata University, Department of Physics, Osmaniye 80000, Turkey
d Abant Izzet Baysal University, Department of Mechanical Engineering, Bolu 14280, Turkey
h i g h l i g h t s
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
Synthesis and characterization of BPOCPA via experimental and theoretical approaches.
An excited-state intra-molecular charge transfer between donor and acceptor regions.
Wide band gap energy of 3.16 eV for metallic bonding and intermolecular interaction.
p–
pꢁ Transitions at 310 and 344 nm due to HOMO ? LUMO (%48.54) and HOMOꢂ1 ? LUMO (%60.75).
Disappearance of four main bending vibrations in the poly(BPOCPA) spectrum.
a r t i c l e i n f o
a b s t r a c t
Article history:
This multidisciplinary study deals with not only the synthesis of p-benzophenoneoxycarbonylphenyl
acrylate (BPOCPA) in the xylene solvent and production of Poly(BPOCPA) by bulk melt polymerization
and solution methods but also the characterization of BPOCPA experimentally (by DCS, UV, IR, 1H NMR
and PL) and theoretically (with DFT method, B3LYP) method for the first time. The FTIR and 1H NMR mea-
surement results verify that the synthesis of the BPOCPA is performed in the yield of 57 wt% without any
impurities. Moreover, DSC melting point belonging to the monomer is found to be about 131.1 °C when
the C and H contents are noted to be 71.397% and 3.554%, respectively. As for the UV–vis spectrometer
Received 22 May 2013
Received in revised form 2 July 2013
Accepted 3 July 2013
Available online 12 July 2013
Keywords:
Organic compounds
Polymers
findings, the absorption wavelength kmax is observed at 344 nm due to the effective p–
pꢁ conjugated seg-
ments in the title compound. The optical band gap energy is observed to be about 3.22 eV, confirming the
presence of the strong electronic donating groups in the monomer. Furthermore, PL spectrum shows that
the compound exhibits strong fluorescence centered at 464.4 nm with a large Stokes shift of 120.4 nm.
Moreover, the theoretical calculation results indicate that the structure is quite stable but obtains high
electronic donor ability for the electrophilic attack (intermolecular interactions), favored by the experi-
mental findings of UV–vis and PL measurements. Theoretical electronic absorption spectra values are also
discussed clearly.
Differential scanning calorimetry
Visible and ultraviolet spectrometers
Ó 2013 Elsevier B.V. All rights reserved.
1. Introduction
began with the proposal of Ringsdorf and co-worker in 1978
[1–3]. According to their findings, there should be a flexible spacer
Side-chain liquid crystalline polymers (SCLCPs) represent a com-
bination of liquid crystalline behavior and polymeric properties.
Shortly, they are defined as the composition of the anisotropy of li-
quid crystalline mesogens with the mechanical properties of the
polymers. The polymeric backbones of SCLCPs are also composed
of primarily polyacrylates, polymethacrylates and polysiloxanes.
Systematic investigations on the synthesis of the side-chain LCPs
between the polymeric backbones and mesogenic side groups to
decouple the motions of the backbone and side groups in the
liquid–crystalline state. This is attributed to the fact that the SCLCPs
easily exist in the form of rod-like (terminal or lateral) and disk-like
mesogens. Thus, in the last decades, there have been a considerable
amount of attention on the examinations on the SCLCPs owing to
their potential applications in solid polymer electrolytes, separation
membranes, optical data storage, non-linear optics, stationary
phases for gas/supercritical-fluid/high-performance liquid chroma-
tography, thermoconducting and display materials [4–8].
⇑
Corresponding author. Tel.: +90 374 254 26 28; fax: +90 374 253 46 42.
E-mail address: karabogafirat@gmail.com (F. Karaboga).
0022-2860/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.molstruc.2013.07.003

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U. Soykan et al. / Journal of Molecular Structure 1049 (2013) 479–487
As well known, majority of side-chain liquid crystal materials
any purification. The dicumyl peroxide (DCP) obtained from Merck
Co., Ltd. with 99.99+% purity is also used as initiator.
are made up of two synthetic routes: (I) free radical polymerization
of acrylic type monomers, bearing mesogenic moieties [9,10], and
(II) hydrosilylation of mesogenic terminal alkenes with linear poly
[(methylhydro)siloxanes], copolymers bearing alkylhydrosiloxane
monomeric units [9,11] or polymer systems being modified with
reactive SiAH bonds [12]. Hence, directly determination of the
reactive regions in the structure is difficult by the experimental
studies. In this respect, the researchers need to use the theoretical
calculation programs to characterize the SCLCPs and interpret the
experimental findings for the technological applications. Even it
is a well-known reality that the computational methods are reli-
able as well as effective to identify the organic compounds because
of their efficiency and accuracy with regard to the evaluation of a
number of molecular properties [13]. It is to be mentioned here
that a suitable quantum chemical method is helpful to predict
compound properties economically and to clarify some experiment
phenomena insightfully [14].
Moreover, quantum chemical methods have widely been used as
the standard techniques for the structural, optical and electrochem-
ical characteristics of molecular systems [15]. Density functional
theory (DFT) and ab initio Hartree Fock (HF) are from the most useful
methods and obtain considerable popularity as an effective general
procedure to study the physical properties of organic compounds.
However, the former (DFT) methods treat the electronic energy
against the electron density of all the electrons simultaneously
while no electron correlation effects are taken into account in the
latter (HF) methods. In other words, only DFT calculation methods
recover the electron correlation in the self-consistent Kohn–Sham
procedure along with the electron density functions [16–18], con-
firming that the DFT methods are the more effective and reliable
as compared to the HF ones. As well known from the literature, in
the DFT method, the Becke’s three parameter hybrid exchange func-
tional combined with the Lee–Yang–Parr non-local correlation func-
tion (DFT/B3LYP) level of theory exhibits good performance on the
characterization of the organic compounds [19,20].
2.2. Synthesis mechanisms of compounds
In this work, the condensation reaction of p-acryloyloxybenzoyl
Chloride (ABC) and p-hydroxybenzophenone (HBP) compounds is
used to synthesize the p-benzophenoneoxycarbonylphenyl
acrylate (BPOCPA). The former compound is prepared refluxing
the p-acryloyloxybenzoic acid (ABA) with thionyl chloride [21].
2.2.1. Synthesis of p-acryloyloxybenzoic acid (ABA)
p-Hydroxybenzoic acid (69.0 g) is added to 500 mL of 2 M NaOH
in a flask equipped with a magnetic stirrer. The solution obtained is
cooled down to the temperature of 0–5 °C, and then acryloyl chlo-
ride (0.5 mol) is added dropwise to the stirred solution for 1 h at
the temperature range and then for 1 h at the room temperature.
With the addition of cool diluted HCl into the reaction mixture
for the neutralization, the solid p-acryloyloxybenzoic acid (ABA)
starts to precipitate slowly. Hence, ABA compound precipitated is
filtered and washed with warm water. The product is recrystallized
from acetone (yield 75%), being superior to that of the literature
[22]. The 1H NMR spectrum of ABA shows a quartet at d 6.3 and
doublets at d 6.0 and d 6.6 corresponding to three protons of
CH2@CHA, and two doublets at d 7.1 and d 8.1 corresponding to
four protons of the C6H4A group. Additionally, the FTIR spectrum
of ABA presents broad bands between 3200 and 2500 cmꢂ1 due
to the carboxylic acid OAH and CAH stretching vibrations. The
strong band due to characteristic C@O stretching vibrations of
ester group is observed at 1742 cmꢂ1
. A strong band at
1688 cmꢂ1 is due to C@O stretching vibrations of aryl carboxylic
acids. The bands at 1600 and 1500 cmꢂ1 are assigned to C@C
stretching vibrations of aromatic compounds. The four bands at
800, 909, 939 and 987 cmꢂ1 are arisen from vinylic CAH out-of-
plane bending vibrations. Scheme 1 illustrates the simplified reac-
tion between p-hydroxybenzoic acid and acryloyl chloride.
In this present study, we endeavor to identify the BPOCPA
monomer with the aid of both the experimental evidences and the-
oretical results for the first time. The DSC, UV–vis spectrometer,
FTIR spectrophotometer, 1H NMR, PL spectrometer and elemental
analysis measurements are performed for the experimental investi-
gations whereas the DFT/B3LYP level of theory is chosen for the the-
oretical calculations. All the results obtained are discussed clearly.
2.2.2. Synthesis of p-acryloyloxybenzoyl chloride (ABC)
ABA (25 g) in the dimethylformamide is refluxed by thionyl-
chloride (250 mL) for the duration of 8 h. The solvent is filtrated
and distilled off in vacuum. The product obtained is purified and
recrystallized from the dichloromethane where the solubility of
the ABC compound is lowered by the addition of the hexane. The
yield of ABC is noted to be about 98 wt%. The reaction is clearly dis-
played in Scheme 2.
2. Experimental details
2.1. Materials
2.2.3. Synthesis of p-benzophenoneoxycarbonylphenyl acrylate
(BPOCPA)
Acetone, dimethyl formamide, ethanol, ethyl methyl ketone,
hexane, trietyl amine, xylene (Merck Co., Ltd.), dichloromethane,
methanol, dimethylsulfoxide, (VWR Co., Ltd.) and ethylacetate
(Riedel-de Haen A Co., Ltd.) are used without any purification dur-
ing the synthesis processes.
Acryloyl chloride, p-hydroxybenzoic acid, thionyl chloride
(Merck Co., Ltd.), 4-hydroxybenzophenone (Alfa Aesar Co., Ltd.)
and the other high purity chemicals for the synthesis of p-benz-
ophenoneoxycarbonylphenyl acrylate (BPOCPA) are used without
The p-benzophenoneoxycarbonylphenyl acrylate is synthesized
as reported previously [21]. Namely, HBP (25.0 g, 0.126 mol) and
12 mL (7.5 g, 0.126 mol) triethylamine are dissolved in the ethyl
methyl ketone (150 mL), and the reaction solution is cooled down
to 0–5 °C in ice bath, and waited for 1 h at this temperature range
and then for 5 h at room temperature, respectively. The solid qua-
ternary ammonium salt is filtered off and washed with access
amount of EMK. The organic solution is also washed successively
with 5% aqueous NaOH solution, diluted HCl and distilled water,
O
O
O
+
OH
O
Cl
O
HO
OH
Scheme 1. Synthesis reaction of ABA compound.

U. Soykan et al. / Journal of Molecular Structure 1049 (2013) 479–487
481
O
O
O
O
OH
Cl
O
+
S
O
Cl
Cl
O
Scheme 2. The simplified reaction between p-acryloyloxybenzoic acid and thionyl chloride.
respectively. The product is precipitated by further addition of dis-
tilled water, and then collected with the aid of a filter. The solid
product is repeatedly recrystallized from ethanol and ethyl acetate
(yield 16 wt%). The purification is carried out by column chroma-
tography. Here, the dichloromethane is used as a mobile phase
while the silica gel is preferred as a stationary phase.
of temperature of 40 °C (yield 54.07%). Thus, the first method for
the polymerization of BPOCPA is found to be more superior to sec-
ond one.
2.4. Instrumentation
Alternatively, the new synthesis method for the monomer is
accomplished refluxing ABC and HBP in xylene. HBP (25.0 g,
0.126 mol) and (26.5 g, 0.126 mol) ABC are refluxed in xylene
(250 mL) for about 3–4 days to produce the dark brown-black
impurity in the reaction medium. The suspension is relaxed by
adding a small amount of hexane. The monomer, BPOCPA is precip-
itated from the reaction solution and then recrystallized from
ethanol and ethyl acetate mixture. Surprisingly, the yield of the
monomer is found to be about 57 wt%, which is one of the most
striking features of this work. Additionally, the synthesis method
is examined by using dioxane, dimethyl sulfoxide and dimethyl
formamide instead of xylene solution; however, the reaction
mechanism fails for all the solutions. The simplified reaction for
the preparation of the monomer is shown in Scheme 3.
NMR spectra, performed with the aid of a Bruker-Spectrospin
Avance DPX 400 Ultra-shield 1H NMR spectrometer in DMSO solu-
tion with a frequency of 400 MHz are reported in parts per million
scales (d scale) downfield from the internal standard tetramethyl-
silane (TMS). UV–vis spectra of the products are recorded by the
unpolarized light at normal incidence in the wavelength range of
400–700 nm, with a JASCO 430 UV–vis spectrophotometer. The
FTIR spectra are recorded on a Shimadzu 8400S FTIR spectropho-
tometer in the region 400–4000 cmꢂ1 with a resolution of 4 cmꢂ1
in the transmission mode. The thermal studies are conducted by
a Setaram DSC 131 Differential Scanning Calorimeter (DSC) at a
heating rate of 10 °C/min with sample sizes of 5–15 mg under
nitrogen atmosphere when Fluorescence spectra are obtained from
a Hitachi F-450 spectrometer. The elemental analysis in terms of
C% and H% is also performed by use of Eurovector EuroEA Elemen-
tal Analyser.
2.3. Polymerization of the BPOCPA
Polymerization of the BPOCPA is exerted by two main methods:
(I) bulk melt polymerization and (II) solution polymerization. The
former method is carried out with the use of initiator, dicumyl per-
oxide (DCP). The mixture of BPOCPA and DCP (2% with respect to
weight of monomer) is annealed in vacuum at the constant tem-
perature of 170 °C for 40 min. The last product, poly(BPOCPA), is
washed repeatedly with EMK, DMSO and methanol to remove
monomer residuals and soluble parts, and then dried under vac-
uum. The yield of the poly(BPOCPA) is found to be about 94.91%.
As for the second polymerization method, the polymerization of
the monomer is carried out in the dimethyl formamid (DMF) and
dimethyl sulfoxide (DMSO). The solution containing 2% (with
respect to weight of BPOCPA) benzoyl peroxide (BPO) is heated
up to 100 °C and waited for the duration of 1 h. The product, poly
(BPOCPA) is precipitated by the methanol addition. After filtering,
the product is washed with methanol and ethyl methyl ketone
(EMK) to remove the remaining unpolymerized monomer residu-
als and other soluble parts, and dried in vacuum at the constant
2.5. Computational studies
The optical and electrochemical properties such as frontier orbi-
tals (HOMO and LUMO), optical band gap (HOMO–LUMO), electro-
static potential (ESP) with 2D total charge density contour and
molecular electrostatic potential (MEP) of the BPOCPA are per-
formed using 2009W version of the GAUSSIAN suite program
[23] with molecular visualization program [24] on the personal
computer by means of the Becke’s three parameter hybrid
exchange functional [25] combined with the Lee–Yang–Parr non-
local correlation function [26] supplemented with the standard
6-31G(d,p) [27,28] level of calculation for the first time.
Moreover, the electronic properties of the title compound are cal-
culated with the aid of the total energies (TE) and the Koopmans’
theorem (KE). The ionization potential corresponding to the mono-
mer is evaluated from the energy difference between the radical
cation and respective neutral compound; IPTE = Ecation ꢂ En;
IPKE = ꢂEHOMO whereas the energy difference between the neutral
Scheme 3. Likely sequence of steps for the formation of BPOCPA compound.

482
U. Soykan et al. / Journal of Molecular Structure 1049 (2013) 479–487
molecule and anion molecule: EATE = En ꢂ Eanion; EAKE = ꢂELUMO
in Fig. 3. It is visible from the figure that 1H isotropic chemical shift
values are observed at 6.45–8.21 ppm. There is doublet at d
6.1 ppm (minimum value) corresponding to Hb proton of vinylic
group and one quartet at d 6.45 ppm corresponding to vinylic Ha
proton. Moreover, the doublet observed at d 6.6 ppm is responsible
for Ha ꢂ Hc trans coupling of vinylic group. The five doublets found
at d 7.45, 7.50, 7.76, 7.86 and 8.21 ppm are peculiar to Hd, Hf, He,
Hg, Hh proton, being related to the single O-coupling of the C6H4-
groups in the structure. The two triplets at d 7.57 and 7.68 ppm
are attributed to Hj and Hi protons obtaining the double O-coupling
of C6H4-groups in the BPOCPA. It is another interesting point ob-
tained from Fig. 2 that no impurities could be noticed from the
1H NMR spectra for the monomer synthesized.
allows us to find the electron affinity of the molecule studied,
respectively. Electronegativity (v), hardness (g), softness (f), and
electrophilicity index ( ) are determined in terms of the ionization
w
potential and electron affinity values [29–32].
IP þ EA
Electronegativity ð
v
Þ :
l
ꢃ ꢂ
v
¼ ꢂ
ð1Þ
ð2Þ
ð3Þ
2
IP ꢂ EA
Chemical hardness ð
gÞ ꢃ
2
1
Softness ðfÞ ¼
2
g
From Fig. 4, one can see the DSC measurement result of BPOCPA
compound. According to the figure, the DSC melting point of BPOC-
PA is found be about 131.1 °C under N2 atmosphere with heating
rate of 10 °C/min.
l2
Electrophilicity Index ðwÞ ¼
ð4Þ
2
g
As for the observation of the C and H contents in the monomer
synthesized, the elemental analysis data of the BPOCPA indicate
that the C content of 71.397% and H content of 3.554% are found
to be in good agreement with the calculated values for the assigned
structure.
3. Results and discussion
The structure of p-benzophenoneoxycarbonylphenyl acrylate
(BPOCPA), which is a novel acrylate monomer to be composed of
benzophenone side group, is identified with the aid of elemental
analysis, FTIR, 1H NMR, UV–vis, DSC techniques and theoretical
approaches.
As well known from the literature, the electronic transitions are
usually classified in terms of the orbitals engaged or specific parts
of the molecule involved. The transitions of
p
(donor)–pꢁ (accep-
tor) and n–pꢁ are the common types of electronic transitions in
the organic compounds [33,34]. The former is named as strong
transition while the latter is termed as the weak transition. The
optical data deduced from the absorption spectra of the title com-
pound are listed in Table 1. As shown from the table, the absorp-
tion wavelength kmax of the BPOCPA is observed at 344 nm, being
3.1. Characterization of p-benzophenoneoxycarbonylphenyl acrylate
Fig. 1 depicts the FTIR spectrum of BPOCPA where the absorp-
tion peaks at 1741 and 1730 cmꢂ1 are characteristic of C@O
stretching vibrations of carbonyl groups. The strong IR band iden-
tified at 1651 cmꢂ1 is assigned to C@O ketone stretching vibrations
of the pendant benzophenone moiety. The moderate band at
3063 cmꢂ1 is attributed to the aromatic CAH stretching vibrations.
The bands observed at 1599 and 1504 cmꢂ1 are due to aromatic
stretching vibrations of C@C bonds in the structure. The strong
bands at 1207 and 1276 cmꢂ1 are corresponding to ester CAOAC
stretching vibrations. The absorption bands due to the monosubsti-
tuted aromatic C-H bending vibrations are found to be in a range of
1000–1200 cmꢂ1. The moderate bands appearing between 823 and
1001 cmꢂ1 represent the vinylic CAH out-of-plane bending
vibrations.
attributed to the effective p–
pꢁ conjugated segments of the mono-
mer such as the C@O and vinylic group. Furthermore, this peak
(kmax) corresponds to vertical excitation as a result of the Frank–
Condon principle [35]. It is another interesting point that the en-
ergy of the optical band gap to be measured from the absorption
onset of the molecule is observed to be about 3.22 eV, confirming
the presence of the strong electronic donating groups such as car-
bonyl and vinylic group [36].
In the photoluminescence spectra, the p-benzophenoneoxycar-
bonylphenyl molecule exhibits strong fluorescence centered at
464.4 nm with a large Stokes shift of 120.4 nm. This may be attrib-
uted to the fact that when the title compound is connected to the
polymer backbone, the molecule can emit bright blue owing to the
Fig. 2 displays the 1H NMR spectra belonging to the BPOCPA
monomer. The proton shifts extracted from the figure are pictured
Fig. 1. FTIR spectrum of the BPOCPA in the solid phase.

U. Soykan et al. / Journal of Molecular Structure 1049 (2013) 479–487
483
Fig. 2. The 1H NMR Spectra of the BPOCPA monomer.
allows us to determine the chemical reactivity and kinetic stability
of a structure [43]. The lower band gap energy the more reactive,
polarizable and less stable the structure becomes. Hence, the (soft)
material obtains a high chemical reactivity and low kinetic stability
[44]. Besides, the optical band gap energy is used to explain the
eventual charge transfer interaction within the molecule for the
biological activity as a consequence of the significant degree of
intramolecular charge transfer (ICT) from the end-capping elec-
tron-donor groups to the efficient electron-acceptor groups
Fig. 3. Proton scheme belonging to the BPOCPA.
through p-conjugated path [45–47].
3D plots of the HOMOs and LUMOs belonging to the BPOCPA
monomer are shown in Fig. 5. It is apparent from the figure that
extended
p-electronic structure in the side chain backbone. Fur-
thermore, it is another interesting point that there seems to be
an excited-state intra-molecular charge transfer (ICT) between
the donor and acceptor regions in the polymers studied [37,38].
both the HOMOs and LUMOs are mostly p-antibonding-type orbi-
tals. The former orbitals are mostly delocalized on the vicinity of
the benzene rings but no translation appears on vinylic and car-
bonyl groups. In contrast, the latter charge densities are localized
mainly on the title compound expect for the hydrogen atoms. Based
on the results obtained, the benzene rings (especially ring-II ꢄ high-
est reactivity) play the significant roles for the potent antioxidant
activity of the organic compound. On the other hand, it is to be men-
tioned here that the concentration of the charge density in the ring-
III is considerably less as compared to the ring-I and ring-II for the
HOMOs. This may be related to the fact that the bond dissociation
enthalpies (BDEs) in the ring-III are higher than in the other rings
of the title compound [48]. As for the LUMOs, the composition of
the monomer clearly reveals high delocalization of charge density
over the entire parts, meaning that the compound with the high
reactive system is highly planar and more powerful inhibitors of
mutagenesis and thus can behave as soft electrophilic [49].
3.2. Computational study
Highest occupied molecular orbital (HOMO) and lowest unoc-
cupied molecular orbital (LUMO) play a crucial role to determine
the optical and electrochemical properties of an organic compound
as well as UV–vis spectra [39]. The interaction between the species
can be interpreted with the aid of HOMO and LUMO information of
the compound. The HOMO is known to be the outermost orbital
containing electrons and behaves as an electron donor. On the
other hand; the LUMO is the innermost orbital containing free
places to accept electrons [40]. According to the molecular orbital
theory, the transition of p–
pꢁ stems from the interaction between
HOMO and LUMO orbital of the title compound [41]. Thereby, the
HOMO energy is directly attributed to the ionization potential
while the energy of the LUMO is directly related to the electron
affinity [42]. In other words, the energy separation between HOMO
and LUMO orbital is described as optical band gap energy that
Moreover, the HOMO and LUMO energies of the title compound
are obtained to be about ꢂ6.85 eV and ꢂ2.65 eV respectively at
B3LYP/6-31G(d,p) basis set. The value of the energy separation
between the HOMO and LUMO (band gap energy) is found to be

484
U. Soykan et al. / Journal of Molecular Structure 1049 (2013) 479–487
Fig. 4. DSC thermogram of BPOCPA.
activity of the former compound is higher than that of the latter
molecule due to the different number of the carbonyl groups in
the title compounds studied [52–58].
Table 1
Summary of the optical properties of the BPOCPA.
Uv–vis results
PL results
The data obtained for the BPOCPA are depicted in Table 2.
Eogpta (eV)
kmax (nm) konset (nm)
kex (nm) kem (nm) Stokes shift (nm)
According to the table, the
v and w values are found to be about
344
385
3.22
464.4
523.8
120.4
4.75 and 5.37 eV, respectively. This may be in accordance with
the fact that although the title structure has possible sites for the
electrophilic attack (being favored by the MEP analysis), the organ-
ic compound is quite stable (being supported by the frontier orbital
a
Estimated from the absorption onset (Eg = 1240/konset).
about 4.20 eV (Table 2). This is associated with the fact that the ti-
tle structure is quite stable [50]. Additionally, in previous work, we
studied on the characterization of the title compound, p-biphenyl-
oxycarbonylphenyl acrylate. It was observed that the HOMO value
is found to be about ꢂ6.21 eV when the optical band gap energy is
obtained to be about 4.76 eV at B3LYP/6-31G(d,p) level of
calculation. Based on the findings obtained (lower band gap and
greater HOMO eigen-value), the electronic donor ability of the
p-benzophenoneoxycarbonylphenyl acrylate (the present com-
pound) is stronger than the p-biphenyloxycarbonylphenyl acrylate
(the studied molecule) [51]. In other words, the antioxidant
examination). Whereas the
g value is also obtained to be about
2.10 eV, the f value of 0.24 eVꢂ1 is observed for the compound
studied, presenting that the monomer synthesized may be useful
in the optic and opto-electronic applications [59,4,2].
3.3. Molecular electrostatic potential and electrostatic potential
Molecular electrostatic potential (MEP) and electrostatic poten-
tial (ESP) being useful characteristics to demonstrate the charge
distributions of an organic compound give the information about
Fig. 5. 3D maps of the HOMO and LUMO of BPOCPA (Positive phase is shown by red regions while negative phase is displayed by green blobs). (For interpretation of the
references to color in this figure legend, the reader is referred to the web version of this article.)

U. Soykan et al. / Journal of Molecular Structure 1049 (2013) 479–487
485
and yellowish colors are found to be the predominance on the mol-
ecule as a consequence of the negative charge distribution.
Table 2
Calculated energy values of the BPOCPA in the ground state with singlet symmetry at
B3LYP/6-31G(d,p) level of theory for the potential technological and industrial
applications.
3.4. Theoretical electronic absorption spectra values of BPOCPA
Quantity
Value
The peak calculated in 344 nm is related to the overlapping of
Lowest MO Eigen value (eV)
Highest MO Eigen value (eV)
HOMO (eV)
ꢂ561.38
1404.74
ꢂ6.85
ꢂ2.65
4.20
p–
pꢁ transition in benzene ring and oscillation effect whereas the
weak absorption peak at 368 nm stems from the n ? pꢁ type tran-
sition in the carbonyl groups. On the other hand, the absorption
maxima defined as the functions of the electron availability are cal-
culated to be about 289, 311, and 341 nm at the TD-B3LYP/6-
31G(d,p) level of theory [64–66] in the THF solution. Based on
the results obtained, the calculation results are found to be shorter
than the experimental evidences [67]. It is attributed to the fact
that the calculated energy transitions are blue shifted from the
experimental findings. However, the agreement between theoreti-
cal data and experimental results is quite acceptable. The percent-
age contribution of the translations evaluated from the Singlet-A
values (CI expansion coefficients) is also another important result
obtained from Table 3. The visible absorption maxima of the mono-
mer synthesized are in accordance with the electron transition be-
tween frontier orbitals (such as translation from HOMO to LUMO;
or HOMOꢂ1 to LUMO+1). The experimental bands observed at 310
and 344 nm result from%48.54 transition of HOMO ? LUMO
and%60.75 transition of HOMOꢂ1 ? LUMO, respectively. Likewise,
the experimental band found at 368 nm may be assigned to a tran-
sition from HOMO-2 to LUMO. It is noted that other one-electron
excitations may also contribute to describe this observed band
[68]. Oscillator strength values are also displayed in Table 3. As
seen from the table that the lowest intense band is computed to
be about 0.0036 at TD-B3LYP/6-31G(d,p) calculation level. Accord-
ing to the oscillator strengths calculated, the least intense band
centered at 368 nm is due to the partly forbidden n–pꢁ transition.
LUMO (eV)
HOMO–LUMO gap (eV), |
(electronegativity) (eV)
(chemical hardness) (eV)
f (Softness) (eV)ꢂ1
(Electrophilicity index) (eV)
DE|
v
g
4.75
2.10
0.24
5.37
w
how the molecules interact with another molecule. The molecular
electrostatic potential, V(r), is known as the interaction energy
between the electrical charge generated from the electrons and
nuclei of the molecule studied and a positive test charge to be
located at a given point r(x,y,z) [50,60]. As a consequence of the
relation with the electronic density, MEP is a very useful descriptor
to decide the sites in the organic molecule for electrophilic attack
and nucleophilic reactions as well as hydrogen-bonding interac-
tions [61–63]. Fig. 6 shows 3D plot of the MEP belonging to the
BPOCPA. Here, electrophilic reactivity is presented by negative
(red) regions whereas nucleophilic reactivity is shown by the posi-
tive (blue) regions. It is obvious from the figure that for the electro-
philic attack (intermolecular interactions) there are three possible
sites on the compound synthesized in this work. These red (nega-
tive) regions are delocalized on the oxygen atoms of the carbonyl
groups. These regions reflect the most electronegative region
(excess negative charge). As for the blue regions in the figure, the
nucleophilic reactivity of the molecule is localized on the hydrogen
atoms. The compound studied is, in this respect, useful to both
bond metallically and interact intermolecularly. Whereas there
are two greater negative regions for p-biphenyloxycarbonylphenyl
acrylate molecule in the previous study, p-benzophenoneoxycar-
bonylphenyl acrylate obtains three main negative regions as a con-
sequence of the strong electronic donating carbonyl groups. This is
related to the fact that the latter compound is more useful for the
intermolecular interactions (electrophilic attacks). Furthermore,
Fig. 7 pictures the electrostatic potential (ESP) image belonging
to the BPOCPA compound. It is apparent from the figure that the
most negative ESP being reflected as a yellowish blob is spread
more over the oxygen atoms, presenting not only the delocaliza-
3.5. Characterization of poly(BPOCPA)
The FTIR and DSC measurements are carried out for the identi-
fication of the poly(BPOCPA). According to the results obtained, the
aromatic C-H stretching vibrations shift from 3063 cmꢂ1 to the
lower value of 3049 cmꢂ1. The calculated C@O stretching vibration
for ester groups in the poly(BPOCPA) is found to be close to the
monomer vibration value (1741 cmꢂ1) whereas the strong band
at 1656 cmꢂ1 is assigned to ketone C@O stretching vibrations be-
tween two phenyl groups. Similarly, the C@C stretching bands
are found to be in the range of 1597–1504 cmꢂ1. As for the ester
CAOAC stretching modes, the strong bands are observed at 1197
and 1267 cmꢂ1. The absorption bands due to monosubstituted aro-
matic CAH bending vibration are found between 1012 and
1160 cmꢂ1. The four bands at 979, 968, 943 and 904 cmꢂ1 observed
in the spectrum of the monomer BPOCPA owing to the vinylic CAH
out-of-bending vibrations disappear completely in the spectrum,
tion of p-electrons over the carbonyl groups but also the extended
conjugation of the vinylic and benzene rings with these groups. On
the other hand, the positive ESP is localized on the rest of the
organic compound, meaning that the ESP map correlates with
electronegativity and partial charges in the structure synthesized
in this work. Moreover, the total charge density contour is given
in the same figure. As seen from the figure, generally the reddish
Fig. 6. 3D map of the molecular electrostatic potential (MEP) map of BPOCPA (Red color depicts the negative regions while blue color illustrates the positive regions of MEP).
(For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

486
U. Soykan et al. / Journal of Molecular Structure 1049 (2013) 479–487
Fig. 7. 3D map of the electrostatic potential (ESP) of BPOCPA.
Table 3
Experimental and theoretical electronic absorption spectra values of BPOCPA.
Excitations
Singlet-A
% Contribution
Wave Length (nm)
Experimental
Oscillator strength (f)
Translations
Calculation
335
Excited state 1
93 ? 98
93 ? 99
96 ? 98
96 ? 99
97 ? 98
97 ? 99
0.25621
0.15314
0.21804
0.12937
0.45095
0.24948
15.66
5.60
11.35
3.99
48.54
14.86
368
0.0036
HOMOꢂ4 ? LUMO
HOMOꢂ4 ? LUMO+1
HOMOꢂ1 ? LUMO
HOMOꢂ1?LUMO+1
HOMO ? LUMO
HOMO ? LUMO+1
Excited state 2
94 ? 98
94 ? 99
96 ? 98
97 ? 98
0.12484
0.12485
0.53788
ꢂ0.37089
0.13479
3.27
3.27
60.75
28.89
3.82
344
310
280
274
0.8012
0.0118
HOMOꢂ3 ? LUMO
HOMOꢂ3 ? LUMO+1
HOMOꢂ1 ? LUMO
HOMO ? LUMO
94 ? 99
HOMOꢂ3 ? LUMO+1
Excited state 3
92 ? 98
93 ? 98
94 ? 98
95 ? 98
95 ? 99
96 ? 98
96 ? 99
97 ? 98
0.14211
0.13947
0.19931
0.49972
0.20528
ꢂ0.19568
ꢂ0.12733
ꢂ0.14109
4.53
4.36
8.91
56.04
9.46
8.59
3.64
4.47
HOMOꢂ5 ? LUMO
HOMOꢂ4 ? LUMO
HOMOꢂ3 ? LUMO
HOMOꢂ2 ? LUMO
HOMOꢂ2 ? LUMO+1
HOMOꢂ1 ? LUMO
HOMOꢂ1 ? LUMO+1
HOMO ? LUMO
confirming the production of the poly(BPOCPA). At the same time,
DSC measurement displays that the homopolymer exhibits two
endotherms at about 198 °C and 231 °C for the liquid crystal-isot-
ropization temperature and the melting point of crystalline do-
mains, respectively. As remembered, the DSC melting point
belonging to the BPOCPA monomer is experimentally observed to
be about 131.1 °C. Based on the change in the endothermic points,
the poly(BPOCPA) is produced successfully. The similar results are
also found in the literature [21]. It is another probable result that
the endothermic shift observed at about 75 °C may stem from
the glass transition temperature, being reported at 69 °C in [21].
As for the future plans, the graft copolymerization of the BPOC-
PA onto high density polyethylene (HDPE) will be performed with
the aid of the bulk melt polymerization method in the content
range of 0–40 wt%. Moreover, characterization of the graft copoly-
mers produced will be conducted by several techniques such as
DSC, UV–vis, 1H NMR, PL and FTIR measurements and the effect
of the poly(BPOCPA) addition level on the microstructural and
mechanical properties (ultimate tensile strength, Young’s modulus
and impact strength) of the grafted HDPE materials via the SEM,
TG/IR and mechanical measurements will be examined seriously.
4. Conclusions
In this multidisciplinary study, we synthesize p-benzophenone-
oxycarbonylphenyl acrylate (BPOCPA) and try to characterize with
the aid of the experimental measurements such as differential
scanning calorimeter, ultra violet-visible spectrometer, Fourier
transform infrared spectrophotometer, nuclear magnetic reso-
nance proton chemical shifts, photoluminescence spectrum, ele-
mental analysis measurements, and theoretical simulations
evaluated from density-functional theory method for the first time.
The poly(BPOCPA) is also produced by two different methods, the
bulk melt polymerization (yield 54.07%) and solution polymeriza-
tion (yield 94.91%) and major conclusions to be evaluated from this
work are as follows:
ꢀ There is only one endotherm point at about 131.1 °C in the
DSC spectrum of the title monomer whereas the poly(-
BPOCPA) exhibits two endotherms at about 198 °C for liquid
crystal-isotropization temperature and 231 °C for the melt-
ing of crystalline domains. The endothermic shift is recorded
as about 75 °C.

U. Soykan et al. / Journal of Molecular Structure 1049 (2013) 479–487
487
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