Structural, spectroscopic and microbiological characterization of the chalcone 2E-1-(2?-hydroxy-3?,4?,6?-trimethoxyphenyl)-3-(phenyl)-prop-2-en-1-one derived from the natural product 2-hydroxy-3,4,6-trimethoxyacetophenone

Article abstract of DOI:10.1016/j.molstruc.2018.11.075

Chalcones are important intermediates in the biosynthesis of biologically active compounds such as flavonoids and their derivatives. In this paper, a new chalcone 2E-1-(2?-Hydroxy-3?,4?,6?-trimethoxyphenyl)-3-(phenyl)-prop-2-en-1-one (HYTPHENYL) was synth

Full text of DOI:10.1016/j.molstruc.2018.11.075

Accepted Manuscript
Structural, spectroscopic and microbiological characterization of the chalcone 2E-1-
(2ʹ-hydroxy-3ʹ,4ʹ,6ʹ-trimethoxyphenyl)-3-(phenyl)-prop-2-en-1-one derived from the
natural product 2-hydroxy-3,4,6-trimethoxyacetophenone
A.M.R. Teixeira, H.S. Santos, P.N. Bandeira, M.S.S. Julião, P.T.C. Freire, V.N. Lima,
B.G. Cruz, P.T. da Silva, H.D.M. Coutinho, D.M. Sena, Jr.
PII:
S0022-2860(18)31387-5
DOI:
https://doi.org/10.1016/j.molstruc.2018.11.075
MOLSTR 25904
Reference:
To appear in: Journal of Molecular Structure
Received Date: 17 August 2018
Revised Date: 15 November 2018
Accepted Date: 22 November 2018
Please cite this article as: A.M.R. Teixeira, H.S. Santos, P.N. Bandeira, M.S.S. Julião, P.T.C. Freire,
V.N. Lima, B.G. Cruz, P.T. da Silva, H.D.M. Coutinho, D.M. Sena Jr., Structural, spectroscopic and
microbiological characterization of the chalcone 2E-1-(2ʹ-hydroxy-3ʹ,4ʹ,6ʹ-trimethoxyphenyl)-3-(phenyl)-
prop-2-en-1-one derived from the natural product 2-hydroxy-3,4,6-trimethoxyacetophenone, Journal of
Molecular Structure (2018), doi: https://doi.org/10.1016/j.molstruc.2018.11.075.
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Structural, spectroscopic and microbiological characterization of the
chalcone
2E-1-(2ʹ-Hydroxy-3ʹ,4ʹ,6ʹ-trimethoxyphenyl)-3-(phenyl)-
prop-2-en-1-one derived from the natural product 2-hydroxy-3,4,6-
trimethoxyacetophenone
A.M.R. Teixeiraa,b*, H.S. Santosc, P.N. Bandeirac, M.S.S. Juliãoc, P.T.C. Freired, V.N.
Limaa, B.G. Cruza, P.T da Silvaa,c, H.D.M. Coutinhoa, D.M. Sena Jr.a
a Department of Biological Chemistry, Regional University of Cariri, Crato, CE, 63105-000, Brazil
b Department of Physics, Regional University of Cariri, Juazeiro do Norte, CE, 63041-145, Brazil
c Science and Technology Centre - Course of Chemistry, State University Vale do Acaraú, Sobral, CE,
62040-370, Brazil
d Department of Physics, Federal University of Ceará, Fortaleza, CE, 60455-760, Brazil
ABSTRACT
Chalcones are important intermediates in the biosynthesis of biologically active
compounds such as flavonoids and their derivatives. In this paper, a new chalcone 2E-1-
(2ʹ-Hydroxy-3ʹ,4ʹ,6ʹ-trimethoxyphenyl)-3-(phenyl)-prop-2-en-1-one
(HYTPHENYL)
was synthesized by the condensation reaction of Claisen-Schmidt in basic medium
between the 2-hydroxy-3,4,6-trimethoxyacetophenone (HTMCX) and benzaldehyde.
The molecular structure of this chalcone was determined by Nuclear Magnetic
Resonance, and characterized by infrared and Raman spectroscopy, at room
temperature. Its electrochemical behavior was also evaluated. Vibrational wavenumber
and wavevector have been predicted using the Density Functional Theory (DFT)
calculations and their normal modes were analyzed in terms of the potential energy
distribution (PED). Furthermore, DFT calculations were carried out to obtain the
molecular orbitals and the electrostatic surface map. Electronic absorption spectrum of
HYTPHENYL was measured and compared with that obtained for the HTMCX
compound. Additionally, analysis of the antimicrobial activity and antibiotic resistance
*Corresponding author. FAX: 55-88-3102 1294, Phone: 55-85-999 224809.
E-mail address: alexandre.teixeira@urca.br

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modulation was carried out to evaluate the antibacterial potential of the HYTPHENYL
chalcone.
Keywords: NMR; Vibrational spectroscopy; UV-VIS; DFT; Voltammetric study,
Antimicrobial activity; Chalcone.
1. Introduction
The chalcones and their derivatives have received great attention because of
their simple structure and the diversity of pharmacological activities that they present
[1-10]. Among them, we can mention anti-cancer [4, 11-13], antioxidant [12], anti-HIV
[14], antibacterial [15, 16], antimalarial [17], anti-infective [18], anti-inflammatory [18]
activities, inhibitors of tyrosine phosphatase A of Mycobacterium tuberculosis [19],
and antifungal [20].
Recently, we have published a paper on antimicrobial and modulatory activities
of the compound 2-hydroxy-3,4,6-trimethoxyacetophenone (C11O5H14, hereafter named
HTMCX) isolated of the stem bark of Croton anisodontus [21]. The results from the
work of Ref. [21] indicated that this natural compound, when associated with amikacin
antibiotic, presents synergism against Pseudomonas aeruginosa 03 and Staphylococcus
aureus 358. These results corroborate with other reports in the literature that combine
natural products with antibiotics against bacteria to decrease microbial resistance [22].
Furthermore, the synthesis of analogues [23, 24] and derived from the natural products
[24] may enable the discovery of new active substances. In this context, we have
synthesized a new chalcone from natural product HTMCX. Also, very recently, we have
reported a complete study of the structural and vibrational properties of this natural
product [25].
In this paper, a new chalcone 2E-1-(2ʹ-Hydroxy-3ʹ,4ʹ,6ʹ-trimethoxyphenyl)-3-
(phenyl)-prop-2-en-1-one (C18O5H18, hereafter named HYTPHENYL) was synthesized
by the condensation reaction of Claisen-Schmidt [26] in basic medium between the
natural compound HTMCX and benzaldehyde. The molecular structure of this chalcone
was determined by Nuclear Magnetic Resonance, and characterized by infrared and
Raman spectroscopy, at room temperature. Its electrochemical behavior was also
evaluated. Vibrational wavenumber and wavevector were predicted using the Density
Functional Theory (DFT) calculations and their normal modes were analyzed in terms

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of the potential energy distribution (PED). Furthermore, DFT calculations were carried
out to obtain the molecular orbitals and the electrostatic surface map. Electronic
absorption spectrum of HYTPHENYL was measured and compared with that obtained
for the HTMCX. Additionally, analysis of the antimicrobial activity and antibiotic
resistance modulation was carried out to evaluate the antibacterial potential of the
HYTPHENYL chalcone. Literature survey reveals that to the best of our knowledge
neither the structural, electrochemical and vibrational properties of chalcone
HYTPHENYL nor the study of antimicrobial activity and modulatory antimicrobial
activity for the HYTPHENYL compound were reported yet. Beyond a complete
characterization of the material, our study points to the potential use of this chalcone in
synergy with antibiotics as antimicrobial agent.
2. Materials and methods
2.1 Synthesis of the chalcone HYTPHENYL
The chalcone synthesis is as shown in Figure 1. The starting materials were the
natural product 2-Hydroxy-3,4,6-trimethoxyacetophenone (HTMCX) (1) and
benzaldehyde (2) commercially obtained from Sigma-Aldrich. The chalcone derivative
(3) was prepared by stirring a solution of HTMCX compound (1) (0.20g; 0.62 mmol),
EtOH (10 mL), NaOH (0.25g; 6,5 mmol), and benzaldehyde (0.1093g; 1.03 mmol) (2)
at room temperature for 2 h. The NMR data confirm that the product of this synthesis is
the chalcone 2E-1-(2ʹ-Hydroxy-3ʹ,4ʹ,6ʹ-trimethoxyphenyl)-3-(phenyl)-prop-2-en-1-one
(HYTPHENYL).
2.2 NMR data of the chalcone HYTPHENYL
1H-NMR showed peaks at δH 3.96 ppm (s) and 3.85 ppm (s) corresponding to
hydrogen atoms from three methoxy groups. The resonances at δH 6.01 (s) is due to the
only hydrogen atom bound to the aromatic ring, and the one at δH 13.94 (1H, s) is due to
a chelated phenol hydroxyl group. Additionally, the signals at δH 7.79 and 7.88 ppm are
13
attributed to hydrogens α and β, respectively. C-NMR and DEPT 135° allowed to
recognize signals for three methoxy groups at δC 60.94, 56.26 and 56.22 ppm, six
aromatic quaternary carbon atoms with peaks at δC 159.6 (C-4´), 158.8 (C-6´), 158.7
(C-2´), 131.2 (C-5´), 107.1 (C-1´) and 135.7 (C-1), six aromatic methines carbon at δC

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130,3 (C-4), 129.1 (C-3/5), δC 128.6 (C-2/6) and 87.4 (C-3´). Additionally, the signal at
δC 193.5 ppm suggests the presence of one conjugated carbonyl group and the signals at
δC 127.7 and δC 142.8 ppm should be associated with C-sp2. The NMR spectra of the 13C
1
(125 MHz) and H (500 MHz) in (CDCl3, δ, ppm, J/Hz) are presented in the
Supplementary Material on Figure S1 and Figure S2, respectively.
2.3 Raman, IR, UV-VIS measurements
FT-Raman spectra were taken using a Bruker RFS100/S FTR system and a
D418-T detector, with the sample excited by means of the 1064 nm line of a Nd:YAG
laser. FT-Raman spectrum was collected from samples confined in screw cap standard
chromatographic glass vials, at a nominal resolution of 4 cm-1 accumulating 60 scans
per spectra and using a laser power of 150 mW.
The infrared spectra were obtained by using a Cary 660 FT-IR spectrometer. In
order to record IR spectra we have grinded the sample in an agate mortar to minimize
scattering on the particle surface and prepared a pellet with KBr by mixing it with the
sample until a uniform mixture was obtained.
The UV absorption spectra of the HTMCX and HYTPHENYL compounds were
recorded in ethanol on a GENESYS™ 10S UV-Vis spectrophotometer.
2.4 Computational method
Calculations using DFT were carried out with the Gaussian 09 programme
package [27]. The B3LYP functional was used with the 6-31 G(d,p) basis set. The
molecular structure of HYTPHENYL used as the input files for Gaussian was drawn in
the ChemSketch program [28] by means of the data obtained from NMR data. The
structure was optimized and the wavenumbers and the atomic displacements for each
mode were then calculated. At the optimized structures of the molecules, the
calculations do not furnish any imaginary frequency. The wavefunctions of electron
densities were obtained for the optimized structure of HYTPHENYL compound. The
wavefunctions generated were used for molecular electrostatic potential (MEP)
calculations. Furthermore, DFT calculations were carried out to obtain the Kohn-Sham
orbitals and the Highest Occupied Molecular Orbital (HOMO) and the Lowest
Unoccupied Molecular Orbital (LUMO), as well as the following quantum chemical
parameters: vertical ionization energy, vertical electron affinity, chemical potential,
electronegativity, global hardness and electrophilicity index. To construct the MEP

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surface and the shape of HOMO and LUMO orbitals, the Chemcraft program [29] was
utilized. Theoretical Raman frequencies were scaled through least-square fits as
suggested by Rauhut and Pulay [30]. For the HYTPHENYL compound we used the
scaling factor of 0.9626 for frequencies below 2000 cm-1, and for frequencies above
2000 cm-1, the scaling factor was 0.9440. The description of the normal modes of
vibration were made based on the potential energy distribution (PED) calculated using
the program VEDA [31]. The calculated vibrational wavenumbers were adjusted to
compare with experimental Raman and infrared frequencies.
2.5 Electrochemical measurements
The electrochemical investigation of chalcone HYTPHENYL was performed
with a conventional three-electrode cell in an µAutolab III potentiostat (Metrohm
Autolab BV, Utrecht, the Netherlands) coupled to a PC microcomputer, using NOVA
2.1.3. software. The working electrode was a glassy carbon electrode, GCE, (Metrohm
Autolab BV) of 3 mm diameter, the counter electrode was platinum coil, and the
reference electrode was Ag/AgCl, Cl– (3.0 mol L-1), all contained in one-compartment
electrochemical cell with a volumetric capacity of 20.0 mL. It was used a volume of
10.0 mL. 0.25 mmol L-1 of HYTPHENYL and 3.0 mmol L-1 of acetophenone HTMCX
stock solutions, prepared by dissolving 7.9 mg in 100 mL of ethanol and 33.9 mg in 10
mL of ethanol + 40 mL of Sorensen buffer, pH 6.96, respectively. Both solutions were
stored in amber flask (to avoid photochemical degradation) and maintained in the
refrigerator during one week maximum.
Cyclic voltammograms were recorded between -400 and 1200 mV, the scan rate
varied from 10 to 100 mVs-1. Nitrogen was used to degas the solution, and the solution
was covered with a nitrogen blanket during experiments. All measurements were carried
o
out at room temperature (25 ± 1 C) and at least in triplicate, and the mean value was
considered.
The oxidation procedure was performed using the stock solutions 0.25 mmol L-1
of HYTPHENYL, and 3.0 mmol L-1 of HTMCX in phosphate buffer (PBS), pH 7.14,
and Sorensen buffer, pH 6.96. The oxidation peak did not disappear and cell current did
not decrease. The oxidized compounds were still electroactive, with an oxidation peak
at a less positive potential. In all reported experiments, the results obtained with GCE in

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the presence of the HYTPHENYL and HTMCX were compared with those obtained
with reference blank electrode operated under the same conditions.
2.6 Microbiological characterization
Bacterial Material
The microorganisms used in sensitivity to HYTPHENYL natural product testing
were obtained from American Type Culture Collection (ATCC) by means of National
Institute for Quality Control in Health (INCQS, Instituto Nacional de Controle de
Qualidade em Saúde) from Oswaldo Cruz Foundation (FIOCRUZ, Fundação Oswaldo
Cruz), Health Ministry, Brazil. The bacterial strains used were Escherichia coli 27 and
Staphylococcus aureus 358. All strains were maintained on heart infusion agar (HIA,
Difco Laboratories Ltd.). Before the tests, the strains were grown for 18 h at 35 ºC in
broth brain heart infusion (BHI, Difco Laboratories Ltd.).
Antimicrobial Activity Test
The initial solution was prepared by dissolving 10 mg of the crystalline
compound HYTPHENYL in 1.0 mL of dymethilsulfoxide (DMSO-Merck, Darmstadt,
Germany) obtaining an initial concentration of 10 mg/mL. This initial solution was then
diluted in a volume of 5.0 mL to be used in all microbiological tests. Afterwards, an
aliquot of the initial solution was dissolved in DMSO to a final concentration of 1024
ꢀg/mL.
The drugs used in the antimicrobial activity tests were the amikacin and
gentamicin antibiotics (Sigma Co., St. Louis, USA). All drugs were diluted in sterile
water, to concentration 5000 mg/mL. For the evaluation of the effect of the compound
HYTPHENYL as modulators of resistance to the antibiotic it was used the amikacin and
gentamicin aminoglycosides (Sigma Co., St. Louis, USA) as well as the bacterial strains
Escherichia coli 27 and Staphylococcus aureus 358.
Minimal inhibitory concentration (MIC) was determined in a microdilution
assay as described previously [32-34]. MIC was defined as the lowest concentration at
which no bacterial growth was observed. For the evaluation of the HYTPHENYL
compound for antibiotic resistance-modifying activity, MIC of the antibiotics was

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determined in the presence or absence of the HYTPHENYL compound at sub-inhibitory
concentrations CIM/8 (1.024 ꢀg/mL).
The antibacterial effect of the compound HYTPHENYL and the modulation of
antibiotic activity (both measured by the MIC) were performed using microtiter plates,
using the methodology described by Coutinho et al. [35]. A growth positive control
containing broth and microorganism was used in the last well of each column.
Microplates were incubated for 24h at 35 ± 2 ºC. A resazurin reagent was used to
indicate the presence of uninhibited bacterial growth (pink colour) or inhibition (blue
colour).
3. Results and discussion
3.1. Molecular structure
Figure 2 shows the molecular structure of HYTPHENYL. This structure is
compatible with our NMR data reported in the Table 1. The base structure of the
HYTPHENYL molecule comprises two six-membered aromatic rings. The ring A is
formed by the atoms C1ʹ, C2ʹ, C3ʹ, C4ʹ, C5ʹ and C6ʹ and the ring B is formed by the
atoms C1, C2, C3, C4, C5 and C6. These two aromatic rings are joined by a three
carbon α,β-unsaturated carbonyl system. Therefore, the molecular structure of
HYTPHENYL is characteristic of a chalcone substance [36].
3.2. Quantum chemical parameters
The frontier molecular orbital theory developed by Kenichi Fukui in 1950's
plays a key role in the understanding of the chemical reactivity [37]. The HOMO is the
outermost orbital containing donor electrons. LUMO is innermost orbital containing
free places to accept electrons. The chemical behavior of HYTPHENYL molecule can
be predicted by the following parameters: HOMO energy, LUMO energy, energy gap
(∆E= ELUMO- EHOMO), vertical ionization energy (I = –EHOMO), vertical electron affinity
(A = –ELUMO), chemical potential (ꢀ = –(I + A)/2), electronegativity (χ = –ꢀ ), global
hardness (η = (I – A)/2) and electrophilicity index (ω = ꢀ2/2η) [38-40]. These quantum
chemical parameters for the optimized geometries of the HYTPHENYL and HTMCX
compounds are given in Table 2. The graphical structures of HOMO and LUMO
molecular orbitals of HYTPHENYL compound are shown in Figure 3. The values of
the energy gap, hardness and chemical potential are smaller in the HYTPHENYL

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compound than the values found for the HTMCX compound [25]. Therefore, the
lowering in these chemical parameters indicates that the reactivity of the HYTPHENYL
compound is greater than that observed in the HTMCX compound. Consequently,
HYTPHENYL compound presents higher electrophilic characters than the HTMCX
compound as noted in the values of electrophilicity index of these molecules (4.01 eV
for HYTPHENYL against 2.68 eV for HTMCX).
The experimental UV absorption spectra of the HYTPHENYL and HTMCX
compounds are shown in Fig. 4. Comparing these spectra we see that Peak 1 remains
essentially unchanged, whereas Peak 2 might have its intensity decreased due the
formation of the enone chain (Cβ=Cα-C=O) of the HYTPHENYL chalcone, and Peak 3
corresponds to the new moiety (ring B).
The electrostatic surface map for HYTPHENYL compound is given in Figure 5.
In this image, blue and pink regions indicate positive and negative charge distributions,
respectively. In the blue regions are spread over the hydrogen atoms and methyl groups
comprising the electrophilic sites of the compound HYTPHENYL. Whereas, the pink
regions, where the oxygen atoms are concentrated are the nucleophilic sites. Therefore,
the charge distribution in the electrostatic surface map for HYTPHENYL compound
shows the existence of the sites where should occur the intra and intermolecular
interactions. The polar nature of this molecule can be examined by the dipole moment
presented by it. The theoretical calculations showed that the value of the dipole moment
for the HYTPHENYL compound is 3.90 Debye (D) while that of dipole moment of
HTMCX was 4.02 D [25]. Therefore, the HTMCX compound is only slightly more
polar than the HYTPHENYL compound.
3.3. Vibrational analysis
The HYTPHENYL molecule has 41 atoms, therefore there are 123 degrees of
freedom, excluding the three rotational modes and the three translational movements are
expected 117 vibrational modes.
The experimental and theoretical FT-Raman spectra of polycrystalline samples
of HYTPHENYL is shown in Figure 6, whereas the FT-IR spectrum of HYTPHENYL
is shown in Figure 7. A complete assignment of the vibrational modes of HYTPHENYL

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is presented in the Table 3. The calculated wavenumber values, not scaled, are given in
the first column, while the calculated and scaled wavenumbers are given in the second
column. The third and fourth columns show the experimental FT-Raman and the
experimental FT-IR wavenumbers, respectively, and the last column lists the
assignments with the percentage contribution of the PED for each vibrational mode.
The Raman and infrared spectra for the HYTPHENYL sample present some
bands which are also characteristic of HTMCX what is expected, since HTMCX
compound is the precursor for the synthesis of HYTPHENYL compound whose ring A
of HTMCX compound is preserved in the synthesis. In the Supplementary Material in
Figure S3 is shown the comparative between the Raman and infrared bands of the
HYTPHENYL and HTMCX compounds.
The FT-IR spectrum of HYTPHENYL shows intense transmittance bands in the
wavenumber range of 1800-400 cm-1. From the FT-Raman spectrum we observe that
modes below 200 cm-1 are associated with external modes and others with internal
modes as discussed below.
The assignment for HYTPHENYL compound shows that most of the bands
observed through FT-Raman and FT-IR spectroscopy corresponds to a mixture of
vibrational modes. Also, it is ascertained that there is a good correspondence between
the scaled and experimental Raman and infrared bands. Torsional vibrations and out of
plane deformations are observed in throughout region of scaled wavenumbers lower
than 1000 cm-1 in the vibrational spectra of HYTPHENYL. It is also noted that in this
region there is predominance of vibrations characteristic of the ring A in both HTMCX
and HYTPHENYL compounds.
In the region of scaled wavenumber between 1000 and 1631 cm-1 of the Raman
and infrared spectra of HYTPHENYL is observed the predominance of the stretching
modes of carbon-carbon and carbon-oxygen atoms. However, in this region is also
possible to observe a marked localization of bending modes of the methyl group. In
fact, wagging vibrations and anti-symmetric bending of the of methyl group are clearly
observed in this compound. A very strong infrared band which is associated with
wagging vibration of the methyl groups of the molecule was observed at 1419 cm-1, and
three strong infrared bands observed at 1439, 1455 and 1468 cm-1 are associated with
the anti-symmetric bending of methyl groups of HYTPHENYL.

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The carbonyl (C=O) stretching vibrations of HYTPHENYL molecular structure
appear associated with stretching modes of carbon-carbon group. In the HTMCX
compound these modes are restricted to two vibrational modes observed in both Raman
and infrared spectra which are localized at scaled wavenumbers 1595 and 1619 cm-1. On
the other hand, in the HYTPHENYL compound the carbonyl (C=O) stretching mode
appears associated with the ketone group CαCβ and is observed in both Raman and
infrared spectra at scaled wavenumber 1429 cm-1. It is noteworthy that the stretching
modes of the C=O carbonyl in the IR spectra have lower intensity than those observed
in other classes of organic compounds.
In the wavenumber region higher than 2800 cm-1 of both Raman and infrared
spectra of the HYTPHENYL are expected the vibrations associated with stretching
modes of CH, methyl and OH groups. For example, in the infrared spectrum of
HYTPHENYL the bands seen at 3113 and 2972 cm-1 are associated respectively with
the stretching modes of CH and CʹH stretching according to the assignment done on the
bases of DFT calculation. In this region of the Raman spectrum the profile of bands
appears with low intensity but even in this manner is possible to note the presence of
several bands. A complete description of all modes appearing in the Raman and infrared
spectra is given in Table 3.
3.4. Voltammetric behavior of the HYTPHENYL
The electrochemical behavior of the HYTPHENYL was studied using cyclic
voltammetry at a GCE, which has been the working electrode of choice in analogous
studies [41]. In the Sorensen buffer, pH 6.96 and GC electrode, the HTMCX and
chalcone derived HYTPHENYL give one well-defined anodic peak (Eap1 = 0.67 V) in
the first cycle curve. Oxidation is an irreversible process confirmed by the absence of
cathodic peak on reverse sweeps. Cyclic voltammograms for the HTMCX and
HYTPHENYL compounds are shown in the Figure 8.
From the second scan, another anodic peak (Eap2) is registered at 0.12 V and the
decreasing of the anodic peak current (at Eap1). On the reverse sweep, a reduction peak
appears at Ecp = 0.06 V only if the second cycle curve has been scanned beforehand, no
other peak appears between –0.4 and +1.0 V, indicating that the final oxidation product
is reduced in the cathodic peak (Ecp); however, it cannot be further oxidized in that
range of potential.

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By the first cycle curves of cyclic voltammograms, anodic peak voltage (Eap1)
values give well-defined peaks, while its half-peak voltage (E1/2) was calculated as the
voltage at which the current equaled half of the maximum anodic peak current. For the
HYTPHENYL, the anodic peak potentials (Eap1) and half-peak potentials (E1/2) are 0.67
V, and 0.041 V, respectively, as is shown in Figure 9.
More details about the process involved in the anodic peak are obtained by
studying the dependence of the experimental current function (Ψ) on the scan rate and
concentration of the HYTPHENYL. The Ψ may be defined as Ψ = Ip/(Aν1/2 c), where A
is the working electrode area, in cm2, ν corresponds to the potential scan rate in V s-1,
and c represents the bulk concentration of HYTPHENYL in mol L-1. This parameter is
more sensitive to the electrode processes [42, 43].
Typical results for different concentrations and scan rates are Ψ 1.1 A (V/s)–1/2
cm–2 L mol–1. The estimated number (with 10 % of error) of electrons exchanged in the
overall electrode process can be calculated by using the experimental Ψ value and
comparing with model compounds that exchange one and two electrons measured with
the same working electrode in similar experimental conditions.
Potassium ferrocyanide was selected as a model for one-electron exchange Ψ =
0.68 A (V/s)–1/2 cm–2 L mol–1, and 1,4-hydroquinone as a two-electron exchange model
[38], Ψ = 1.4 A (V/s)–1/2 cm–2 L mol–1. The value of Ψ 1.2 A (V/s)–1/2 cm–2 L mol–1
indicates that the overall electrode process for HYTPHENYL involves two electrons per
molecule. These data lead to the conclusion that in the Sorensen buffer, pH 6.96, the
oxidation of HYTPHENYL may comprise two successive one electron transfers at
similar formal potential. Thus being E0
E0 , only one peak is detected in the first
1
2
anodic scan [44].
A proposed oxidation mechanism for the HYTPHENYL compound involves the
formation of a phenoxyl radical resulting from the one-electron abstraction from the
2ʹ-hydroxyl group followed by abstraction of H+ ion. Subsequently, this phenoxyl
radical most probably forms a dimer. [45]. The introduction of another aromatic ring B
on structure of the HTMCX seems to affect the oxidation capacity of the
HYTPHENYL, because this compound is more easily oxidized (Eap = 0.67 ± 0.04 V)
than HTMCX compound (Eap = 0.92 ± 0.02 V), Figure 8.

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A plausible explanation for this observation is that the presence of electron-
donating phenyl group (ring B) increases the electron density of the ring thus increasing
the strength of the hydrogen bond between the hydrogen of the hydroxyl group and the
oxygen of the carbonyl (C=O), hindering the removal of hydrogen. Finally, a good
linearity (r = 0.990) for the relationship of the anodic peak current and square root of
scan rate was achieved, which indicates diffusion control of HYTPHENYL oxidation
on the GCE surface.
3.5. Antimicrobial activity and modulatory antibiotic activity
The MIC of the HYTPHENYL compound was 1024 ꢀg/L for all bacterial strains
tested, thereby no antibacterial activity was detected, revealing it as inactive against the
microorganisms tested. However, modulatory activity of antibiotics was observed to
HYTPHENYL compound against strains of Escherichia coli 27 and Staphylococcus
aureus 358.
In the determination of MIC, an effect is regarded as synergistic when a
favorable contribution is observed in the action of the antibiotic associated with the
compound, with a decreasing in the MIC. On the other hand, an antagonistic effect
happens in reverse, that is, occurs an increasing in the MIC on account the action of the
antibiotic associated with the compound.
The MIC of the amikacin aminoglycoside in the presence of the HYTPHENYL
compound in the MIC/8 concentration (128 ꢀg/mL), against strains of Escherichia coli
27 and Staphylococcus aureus 358 showed a significant inhibitory effect with
significance with p < 0.01 on the bacterial growth, as can be seen in Figure 10. These
results indicate that the HYTPHENYL compound showed synergistic effects against
these bacteria strains when it is associated with amikacin antibiotic.
It is worth mentioning that chalcone derivative have been used in preparation of
drug for providing antibacterial activity against gram-positive bacteria, preferably
methicillin-resistant Staphylococcus aureus [46]. In the MIC of the gentamicin
aminoglycoside in the presence and absence of the HYTPHENYL compound in the
MIC/8 concentration (128 ꢀg/mL) is observed a synergy against strain of Escherichia
coli 27 and no effect on the bacterial growth was detected against strain of
Staphylococcus aureus 358, as can be seen in Figure 11.

ACCEPTED MANUSCRIPT
Recent studies have shown that the natural product HTMCX (which is the
precursor of synthesis of HYTPHENYL compound) presents synergism against strains
of Pseudomonas aeruginosa 03 and Staphylococcus aureus 358 in the association with
the amikacin aminoglycoside [21]. On the other hand, no effect on the bacterial growth
was detected against strains of Escherichia coli 27 and Staphylococcus aureus 358
when the natural product HTMCX was associated with the gentamicin antibiotic [21].
Therefore, the combination of this new chalcone HYTPHENYL with the
gentamicin and amikacin aminoglycosides may be useful for the treatment against
strains of Escherichia coli 27 and Staphylococcus aureus 358.
4. Conclusions
In this work a novel chalcone HYTPHENYL was synthesized by the
condensation reaction of Claisen-Schmidt in basic medium between the natural
compound HTMCX and benzaldehyde and its molecular structure was determined by
Nuclear Magnetic Resonance. Additionally, we have reported for the first time the
vibrational spectra of polycrystalline samples of HYTPHENYL by FT-IR (between 400
and 3200 cm-1) and FT-Raman (between 0 and 3200 cm-1) spectroscopy. DFT
calculations were performed, using the Gaussian 09 package with the B3LYP functional
and 6-31G(d,p) basis set, in order to obtain information about the normal modes of
vibrations, allowing a complete assignment, and several quantum chemical parameters
of the HYTPHENYL chalcone. From the voltammetric study was possible to obtain an
understanding for the electrochemical mechanism in aqueous medium of the HTMCX
and HYTPHENYL. Antimicrobial and modulatory antibiotic activities of the
HYTPHENYL compound were investigated. Significant modulatory activity of the
antibiotics tested was observed for HYTPHENYL against strains of Escherichia coli 27
and Staphylococcus aureus 358. The HYTPHENYL showed synergistic effects against
these bacteria strains when associated with amikacin antibiotic. Other synergistic effect
could be observed for Escherichia coli 27 in the presence of HYTPHENYL with the
gentamicin antibiotic. It is important to note that, in previous results, HTMCX did not
show antimicrobial modulatory activity against Escherichia coli when associated with
the gentamicin antibiotic. Therefore, these results demonstrate that HYTPHENYL

ACCEPTED MANUSCRIPT
compound presents potential antimicrobial activity and may contribute to the control of
Escherichia coli and Staphylococcus aureus bacterial resistance.
Acknowledgments
We thank CENAPAD-SP for the use of the Gaussian09 software package and
for computational facilities made available through the project “proj373”. Financial
support from FUNCAP and CNPq is also acknowledged. A.M.R. Teixeira, Ph.D, also
acknowledges financial support from the PQ/CNPq-2015 (Grant#: 303963/2015-8).
H.S. Santos acknowledges financial support from the PQ-BPI/FUNCAP (Grant#: BP2-
0107- 00026.01.00/15). D.M. Sena Jr. acknowledges financial support from PQ/CNPq-
2017 (Grant#: 313407/2017-7). P.T.C. Freire thanks financial support from PRONEX
FUNCAP/CNPq (Grant#: PR2-0101-00006.01.00/15). Authors also acknowledge Dr.
Antonio César Honorato Barreto for the support in the spectroscopy measurements.
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CAPTION FOR THE FIGURES:
Figure 1: Scheme of the synthesis of the HYTPHENYL chalcone.
Figure 2. Molecular structure in ball and stick model with atom numbering for
HYTPHENYL.
Figure 3: The frontier HOMO and LUMO orbitals for the HYTPHENYL chalcone.
Figure 4: Experimental UV absorption spectra of the HYTPHENYL and HTMCX
compounds.
Figure 5: The electrostatic surface map for the HYTPHENYL chalcone.
Figure 6: Experimental and theoretical FT-Raman spectra of the HYTPHENYL in the
spectral range from 3200–2600 cm−1 and 1800–0 cm−1.
Figure 7: Experimental FT-IR spectrum of the HYTPHENYL in the spectral range
from 3200–2500 cm−1 and 1800–400 cm−1.
Figure 8: Cyclic voltammograms recorded on GCE in: ( ) Sorensen buffer, pH 6.96,
with ( ) HYTPHENYL 25 µmol L-1 and ( ) HTMCX 300 µmol L-1. Experimental
conditions: Einitial = Efinal = –0,40 V; Eλ1 = 1,20 V; Eλ2 = –0,40 V. Scan rate: (A) 10
mVs-1 and (B) 100 mVs-1.
Figure 9: Cyclic voltammograms recorded on GCE in: ( ) blank, HYTPHENYL 25
µmolL-1 with ( ) PBS, pH 7.14, and ( ) Sorensen buffer, pH 6.96. Experimental
conditions: Einitial = Efinal = –0,40 V; Eλ1 = 1,00 V; Eλ2 = –0,40 V. Scan rate: (A) 10
mVs-1 and (B) 100 mVs-1.
Figure 10: Minimum inhibitory concentration (MIC) of amikacin aminoglycoside in
the presence and absence of the HYTPHENYL compound in a MIC/8 concentration

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(128 ꢀg/mL) towards Escherichia coli 27 and Staphylococcus aureus 358. Statistically
significant value with **p<0.01.
Figure 11: Minimum inhibitory concentration (MIC) of gentamicin aminoglycoside in
the presence and absence of the HYTPHENYL compound in a MIC/8 concentration
(128 ꢀg/mL) towards Escherichia coli 27 and Staphylococcus aureus 358. Statistically
significant value with ***p<0.001.
CAPTION FOR THE TABLES:
1
13
Table 1: H and C NMR data for the HYTPHENYL chalcone (in CDCl3), J in Hz.
Chemical displacements δC and δH are in ppm.
Table 2: Quantum chemical parameters for the optimized geometries of HYTPHENYL and
HTMCX compounds (eV).
Table 3: Calculated vibrational wavenumbers unscaled and scaled by the scale factors
0.9626 (20 cm-1 to 2000 cm-1) and 0.9440 (2000 cm-1 to 4000 cm-1), experimental
Raman and transmittance band positions and assignment of vibrational modes for the
HYTPHENYL.
SUPPLEMENTARY MATERIAL
Figure S1: NMR spectrum of 13C (125 MHz) in (CDCl3, δ, ppm, J/Hz) for
HYTPHENYL.
1
Figure S2: NMR spectrum of H (500 MHz) in (CDCl3, δ, ppm, J/Hz) for
HYTPHENYL.
Figure S3: Comparative between the Raman and infrared bands of the HYTPHENYL
and HTMCX compounds.

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1
13
Table 1: H and C NMR data for the chalcone HYTPHENYL (in CDCl3), J in Hz.
Chemical displacements δC and δH are in ppm.
C
δC
δH
1’
2’
3’
4’
5’
107.1
158.8
131.2
159.6
87.4
6.01 (s)
6’
158.7
60.9
56.3
MeO-3
MeO-4
MeO-6
C=O
1
3.85 (s)
3.96 (s)
3,96 (s)
56.2
193.5
135.7
128.6
2/6
7.60 (dd, J = 7.53; 1.77
Hz)
3/5
4
Cα
Cβ
129.1
130.3
127.7
142.8
7.43 (m)
7.42 (m)
7.79 (d, J = 15.60 Hz)
7.88 (d, J = 15.60 Hz)

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Table 2: Quantum chemical parameters for the optimized geometries of HYTPHENYL and
HTMCX compounds (eV).
Compound
EHOMO ELUMO
I
5.59
5.67
A
2.02
1.23
∆E
3.57
4.44
µ
-3.81
-3.45
χ
3.81
3.45
η
1.79
2.22
ω
4.01
2.68
-5.59
-2.02
HYTPHENYL
HTMCX*
-5.67
-1.23
*Data of HTMCX were taken from Ref. [25].

Table 3: Calculated νibrational waν
enumbers unscaled and scaled by the scale factors 0.9626 (20 cm-1 to 2000 cm-1)
and 0.9440 (2000 cm-1 to 4000 cm-1), experimental Raman and transmittance band positions and assignment of
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vibrational modes for the HYTPHENYL.
Assignment of vibrational modes for the HYTPHENYL with PED* (%)
ωscal
ωcαlc
ωFT-Rαmαn ωFT-IR
12
18
20
12
17
19
τ (C5ʹC6ʹC1ʹC) (10) + τ (C6ʹC1ʹCCα) (12) + τ (C8ʹO4C4ʹC5ʹ) (47)
τ (C5ʹC6ʹC1ʹC) (18) + τ (C6ʹC1ʹCCα) (26) + τ (C8ʹO4C4ʹC5ʹ) (17)
τ (CαCβC1C2) (59) + τ (C1ʹCCαCβ) (31)
47
67
77
102
103
111
121
147
198
45
64
74
98
δ (CαCβC1) (26) + δ (C1ʹCCα) (19) + δ (CCαCβ) (28)
τ (C4ʹC5ʹC6ʹC1ʹ) (14) + τ (C7ʹO5C6ʹC5ʹ) (33) + τ( C1ʹO4C4ʹC5ʹ) (12)
τ (C5ʹC6ʹC1ʹC) (12) + τ (C1ʹCCαCβ) (10) + τ (CCαCβC1) (15) + γ (CβC2C6C1) (12)
τ (C2ʹC3ʹC4ʹC5ʹ) (20) + τ (C7ʹO5C6ʹC5ʹ) (11) + τ (C9ʹO3C3ʹC4ʹ) (15)
τ (C7ʹO5C6ʹC5ʹ) (12) + τ (C9ʹO3C3ʹC4ʹ) (32)
τ (C3ʹC4ʹC5ʹC6ʹ) (10) + τ (C1ʹCCαCβ) (23) + τ (C9ʹO3C3ʹC4ʹ) (12)
τ (C6ʹC1ʹCCα) (22) + τ (C7ʹO5C6ʹC5ʹ) (14)
δ (O3C3ʹC2ʹ) (12) + τ (HC9ʹO3C3ʹ) (27) + τ (C9ʹO3C3ʹC4ʹ) (18)
τ (C3ʹC4ʹC5ʹC6ʹ) (15) + τ (C2ʹC3ʹC4ʹC5ʹ) (15) + τ (C4ʹC5ʹC6ʹC1ʹ) (19) + γ (O4C5ʹC3ʹC4ʹ)
(12)
65m
86m
99
107
116
142
191
137vw
201
206
230
243
264
277
286
312
324
356
376
413
193
198
221
234
254
267
275
300
312
343
362
398
δ (C6ʹC1ʹC) (16) + δ (CβC1C6) (11) + δ (O5C6ʹC5ʹ) (17) + δ (C7ʹO5C6ʹ) (14)
δ (O4C4ʹC3ʹ) (15) + δ (O5C6ʹC5ʹ) (16)
δ (C9ʹO3C3ʹ) (18) + γ (O3C4ʹC2ʹC3ʹ) (22)
τ (HC8ʹO4C4ʹ) (24) + τ (HC8ʹO4C4ʹ) (19) + τ (HC8ʹO4C4ʹ) (15) + τ (C2ʹC3ʹC4ʹC5ʹ) (13)
δ (O4C4ʹC3ʹ) (14) + δ (CβC1C6) (13) + δ (C8ʹO4C4ʹ) (16)
τ (C6C5C4C3) (14) + τ (C3ʹC4ʹC5ʹC6ʹ) (30) + τ (CCαCβC1) (21)
τ (HC7ʹO5C6ʹ) (25) + τ(HC7ʹO5C6ʹ) (14) + τ (HC7ʹO5C6ʹ) (12)
τ (C5ʹC6ʹC1ʹC) (23) + τ (C3ʹC4ʹC5ʹC6ʹ) (22)
δ (O3C3ʹC2ʹ) (24)
δ (C6ʹC1ʹC) (14) + δ (C8ʹO4C4ʹ) (31)
δ (C2ʹC3ʹC4ʹ) (10) + δ (C3ʹC4ʹC5ʹ) (16) + δ (O3C3ʹC2ʹ) (11)
τ (HC2C3C4) (10) + τ (HC6C5C4) (12) + τ (C6C5C4C3) (33) + τ (C5C4C3C2) (20) +
τ (C1C2C3C4) (18)
287vw
325vw
382vw
429
439
467
498
501
514
574
592
622
413
423
450
479
482
495
553
570
599
420vw
453vw
417m
454m
ν (C1ʹC) (12) + δ (C4ʹC5ʹC6ʹ) (16) +δ (C8ʹO4C4ʹ) (11)
δ (O2C2ʹC1ʹ) (33)
δ (C7ʹO5C6ʹ) (11)
γ (CβC2C6C1) (33)
δ (CαCβC1) (10) + δ (C1ʹCCα) (15)
δ (C9ʹO3C3ʹ) (23)
ν (C3ʹC4ʹ) (18) + ν (O4C4ʹ) (10) + δ (C2ʹC3ʹC4ʹ) (15)
δ (O1CCα) (26) + δ (C1C2C3) (18)
487vw
499vw
517vw
577vw
593vw
486m
496vw
575s
595vw
τ (HC5ʹC6ʹC1ʹ) (23) + γ (Ο1C3ʹC1ʹC2ʹ) (22) + γ (Ο2C5ʹC3ʹC4ʹ) (28)
633
641
655
693
609
617
631
667
δ (C6C5C4) (22) + δ (C4C3C2) (38) + δ (C1C2C3) (13)
ν (C1ʹC) (11) + δ (O1CCα) (10) + δ (C3ʹC4ʹC5ʹ) (11)
γ (O1CαC1ʹC) (15) + γ (O5C5ʹC1ʹC6ʹ) (40)
τ (C1C2C3C4) (13) + γ (O2C3ʹC1ʹC2ʹ) (13) + γ (O3C4ʹC2ʹC3ʹ) (13) + γ (O4C5ʹC3ʹC4ʹ)
(15)
618vw
630vw
656vw
617m
701
731
753
767
782
675
704
725
738
753
688vs
720vs
757vs
765vs
τ (HC4C5C6) (10) + τ (C3ʹC4ʹC5ʹC6ʹ) (10) + τ (C1C2C3C4) (26) + γ (O2C3ʹC1ʹC2ʹ) (13)
γ (O1CαC1ʹC) (32)
δ (O4C4ʹC3ʹ) (11) + δ (O5C6ʹC5ʹ) (21)
ν (O3C3ʹ) (14) + δ (O1CCα) (16) + δ (C5C4C3) (10)
τ (HC3C4C5) (11) + τ (HC4C5C6) (10) + τ (HC5C4C3) (11) + τ (C1C2C3C4) (17) +
γ (O1CαC1ʹC) (13) + γ (CβC2C6C1) (13)
721vw
729vw
756vw
802
851
853
899
916
932
966
973
772
819
821
865
882
897
930
937
768vw
781vw
798vw
835vw
872vw
902vw
τ (HC5ʹC6ʹC1ʹ) (69)
ν (CβC1) (10) + δ (C5C4C3) (19)
792vs
837s
871vs
893vs
τ (HC2C3C4) (24) + τ (HC6C5C4) (27) + τ (HC3C4C5) (21) + τ (HC5C4C3) (19)
τ (HCαCβC1) (57)
δ (CαCβC1) (11) + δ (O23CCα) (10) + δ (CCαCβ) (14)
τ (HCαCβC1) (11) + τ (HC2C3C4) (24) + τ (HC6C5C4) (22) + τ (HC4C5C6) (29)
τ (HO2C2ʹC3ʹ) (92)
τ (HC2C3C4) (18) + τ (HC6C5C4) (15) + τ (HC3C4C5) (25) + τ (HC5C4C3) (33)

989
952
ν (O4C4ʹ) (31) + ν (O3C9ʹ) (13)
999
962
977
969vw
964vs
τ (HC3C4C5) (23) + τ (HC4C5C6) (30) + τ (HC5C4C3) (17) + τ (C6C5C4C3) (10)
δ (C6C5C4) (33) + δ (C4C3C2) (16) + δ (C5C4C3) (20)
ACCEPTED MANUSCRIPT
1015
1026
1037
1045
1056
1111
1115
1157
1171
1176
1177
1189
1209
1218
1223
1239
1240
1248
1274
1320
1332
1356
1357
1368
1381
1477
1482
1490
1492
1500
1503
1504
1508
1516
1518
1527
1531
1540
1615
1629
1632
1657
1677
1694
2871
3019
3028
3058
3095
3111
3137
3148
3152
3157
3177
3180
3185
3194
988
998
990w
1000m
990vs
998vs
1009vs
1025m
1074vs
ν (O5C7ʹ) (32) + ν (O4C8ʹ) (13) + δ (C4ʹC5ʹC6ʹ) (12)
τ (HCαCβC1) (15) + τ (HCβC1C2) (70)
ν (O3C9ʹ) (50)
ν (C4C3) (21) + ν (C5C4) (27)
ν (C6C5) (12) + ν (C3C2) (19) + δ (HC2C3) (10) + δ (HC6C5) (12) + δ (HC4C3) (15)
ν (CCα) (19) + ν (O4C8ʹ) (19)
1006
1017
1069
1073
1114
1127
1132
1133
1145
1164
1172
1177
1193
1194
1201
1226
1271
1282
1305
1306
1317
1329
1422
1427
1434
1436
1444
1447
1448
1452
1459
1461
1470
1474
1482
1555
1568
1571
1595
1614
1631
2710
2850
2858
2887
2922
2937
2961
2972
2975
2980
2999
3002
3007
3015
1027vw
1085s
1117vw
1123vs
ν (O2C2ʹ) (16) + ν (O5C7ʹ) (21)
r (C8ʹH3) (26) + τ (HC8ʹO4C4ʹ) (70)
r (C7ʹH3) (26) + τ (HC7ʹO5C6ʹ) (70)
r (C9ʹH3) (26) + τ (HC9ʹO3C3ʹ) (70)
δ (HC3C2) (17) + δ (HC4C3) (30) + δ (HC5C4) (16)
δ (HC2C3) (26) + δ (HC6C5) (19) + δ (HC3C2) (13) + δ (HC5C4) (15)
r (C9ʹH3) (10) + τ (HC9ʹO3C3ʹ) (44)
τ (HC8ʹO4C4ʹ) (27)
ν (C1ʹC) (11) + δ (HC5ʹC6ʹ) (18) + δ (HCαCβ) (13)
ν (C1C2) (13) + ν (CβC1) (21) + δ (HCβCα) (16)
ν (O4C4ʹ) (13) + ν (O5C6ʹ) (14) + δ (HC5ʹC6ʹ) (14)
ν (C4ʹC5ʹ) (13) + ν (O3C3ʹ) (24)
1154vw
1181m
1152vs
1204m
1242m
1268s
1206vs
1246vs
1268vs
ν (C2ʹC3ʹ) (17)
δ (HCβCα) (17)
ν (O2C2ʹ) (18)
1302vw
1318m
1287vs
ν (CαCβ) (13) + ν (C1C2) (11) + δ (HCβCα) (30)
δ (HC2C3) (24) + δ (HC6C5) (22) + δ (HC4C3) (13)
ν (C5ʹC6ʹ) (10) + δ (HCαCβ) (24)
wag (C9ʹH3) (54) + wag (C8ʹH3) (14)
wag (C9ʹH3) (10) + wag (C8ʹH3) (11) + wag (C7ʹH3) (34)
δ (HC4C3) (12) + δas (C9ʹH3) (12)
δ (HC4C3) (10) + δas (C9ʹH3) (22)
δas (C8ʹH3) (63) + τ (HC8ʹO4C4ʹ) (12)
δas (C9ʹH3) (19) + δas (C8ʹH3) (15) + δas (C7ʹH3) (24)
δas (C7ʹH3) (69) + τ (HC7ʹO5C6ʹ) (14)
δas (C8ʹH3) (62) + τ (HC8ʹO4C4ʹ) (11)
δas (C8ʹH3) (17) + δas (C7ʹH3) (33)
δ (HO2C2ʹ) (17) + δas (C7ʹH3) (10)
δas (C9ʹH3) (77) + τ (HC9ʹO3C3ʹ) (14)
ν (O1C) (12) + δas (C7ʹH2) (28) + wag (C8ʹH3) (10)
δ (HC2C3) (17) + δ (HC6C5) (15) + δ (HC3C2) (15) + δ (HC5C4) (19)
ν (O1C) (20) + ν (C4ʹC5ʹ) (14)
ν (C3C4) (15)
ν (C5ʹC6ʹ) (12) + ν (C3ʹC4ʹ) (10) + ν (C3C4) (10)
ν (C6C5ʹ) (30) + ν (C3C2) (10)
ν (C2ʹC3ʹ) (15) + δ (HO2C2ʹ) (30)
ν (CαCβ) (44) + ν (CO1) (13)
ν (O2H) (95)
νs (C9ʹH3) (99)
νs (C7ʹH3) (100)
νs (C8ʹH3) (99)
νas (C7ʹH3) (100)
1317vs
1333vs
1419vs
1440w
1439vs
1455vs
1468vs
1460vw
1487s
1554vs
1558vs
1584s
1576m
1596vs
1624vs
2842vw
2882vw
2946vw
2975vw
1629vs
2881m
2915m
2946m
νas (C9ʹH3) (100)
νas (C8ʹH3) (99)
νas (C9ʹH3) (99)
νas (C7ʹH3) (89)
2972m
2988vw
3007vw
2986m
3004m
νas (C8ʹH) (98)
ν (CβH) (56) + ν (C2H) (23) + ν (C3H) (10)
ν (CβH) (37) + ν (C3H) (15) + ν (C4H) (18) + ν (C5H) (19)
ν (C2H) (36) + ν (C6H) (10) + ν (C5H) (35)
ν (C2H) (22) + ν (C6H) (16) + ν (C3H) (19) + ν (C4H) (31) + ν (C5H) (11)

3203
3210
3255
3281
3024
3030
3073
3097
3021m
3113m
ν (C6H) (47) + ν (C3H) (29)
ν (C6H) (21) + ν (C3H) (20) + ν (C4H) (31) + ν (C5H) (23)
ACCEPTED MANUSCRIPT
3058vw
ν (C5ʹH) (99)
ν (CαH) (99)
*
Only PED values greater that 10 % are gives.
Nomenclature: τ = torsion; sc= scissoring; δ = deformation; δas
=
anti-symmetric bending, γ = deformation out
of plane; δout = deformation out of plane; ν = stretching; νas = asymmetric stretching; νs = symmetric stretching.
vs=very strong ; s = strong; m = medium; w = weak; vw =very weak.

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