New organic single crystal of (benzylthio)acetic acid: Synthesis, crystal structure, spectroscopic (ATR-FTIR, 1H and 13C NMR) and thermal characterization

Article abstract of DOI:10.1016/j.molstruc.2016.01.016

(Benzylthio)acetic acid (Hbta) was synthesized with 78% yield from benzyl chloride and thiourea as substrates. Well-shaped crystals of Hbta were grown by slow solvent evaporation technique from pure methanol. The compound was investigated by single-crystal X-ray and powder diffraction techniques and was also characterized by other analytical methods, like ATR-FTIR, ¹H and ¹³C NMR and TG/DSC. The acid molecule adopts bent conformation in the solid state. The crystal structure of Hbta is stabilized by numerous intermolecular interactions, including O-H···O, C-H···O, C-H···S and C-H···π contacts. Thermal decomposition of the obtained material takes place above 150 °C.

Full text of DOI:10.1016/j.molstruc.2016.01.016

Accepted Manuscript
New organic single crystal of (benzylthio)acetic acid: Synthesis, crystal structure,
spectroscopic (ATR-FTIR, 1H and 13C NMR) and thermal characterization
Justyna Sienkiewicz-Gromiuk, Bogdan Tarasiuk, Liliana Mazur
PII:
S0022-2860(16)30016-3
10.1016/j.molstruc.2016.01.016
MOLSTR 22132
DOI:
Reference:
To appear in: Journal of Molecular Structure
Received Date: 12 October 2015
Revised Date: 8 January 2016
Accepted Date: 11 January 2016
Please cite this article as: J. Sienkiewicz-Gromiuk, B. Tarasiuk, L. Mazur, New organic single crystal of
(benzylthio)acetic acid: Synthesis, crystal structure, spectroscopic (ATR-FTIR, 1H and 13C NMR) and
thermal characterization, Journal of Molecular Structure (2016), doi: 10.1016/j.molstruc.2016.01.016.
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ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
New organic single crystal of (benzylthio)acetic acid: Synthesis, crystal
1
structure, spectroscopic (ATR-FTIR, H and 13C NMR) and thermal
characterization
Justyna Sienkiewicz-Gromiuka,*, Bogdan Tarasiukb, Liliana Mazura
aDepartment of General and Coordination Chemistry, Faculty of Chemistry, Maria Curie-Skłodowska University, M.C. Skłodowska Sq. 2,
20-031 Lublin, Poland
bDepartment of Organic Chemistry, Faculty of Chemistry, Maria Curie-Skłodowska University, Gliniana Str. 33, 20-614 Lublin, Poland
Abstract
(Benzylthio)acetic acid (Hbta) was synthesized with 78 % yield from benzyl chloride and thiourea as
substrates. Well-shaped crystals of Hbta were grown by slow solvent evaporation technique from pure
methanol. The compound was investigated by single-crystal X-ray and powder diffraction techniques and was
1
also characterized by other analytical methods, like ATR-FTIR, H and 13C NMR and TG/DSC. The acid
molecule adopts bent conformation in the solid state. The crystal structure of Hbta is stabilized by numerous
intermolecular interactions, including O−H···O, C−H···O, C−H···S and C−H···π contacts. Thermal
decomposition of the obtained material takes place above 150 °C.
Keywords (Benzylthio)acetic acid; Hbta; Crystal structure; NMR; ATR-FTIR; Thermal behaviour
1. Introduction
The (benzylthio)acetic acid (Hbta) belongs to the group of compounds named aromatic thiocarboxylic acids
containing ″soft″ sulphur and ″hard″ oxygen donor atoms. Hbta is a monocarboxylic heteroligand which is
composed of flexible −CH2−S−CH2− group, with unpaired spins on sulphur atom, located between the phenyl
ring and carboxylic moiety.
In organic synthesis Hbta is used as a key intermediate for the synthesis of 3-(4-methoxy-benzylidene)-
isothiochroman-4-one [1] belonging to the spiro-heterocyclic compounds, which can act as anti-tumorous, anti-
tubercular and anti-HIV agents [2-4]. Hbta is also involved in the enantioselective synthesis of 4-(2-hydroxy-
(1R)-phenylethyl)-thiomorpholin-3-one [5] derived from the group of 2-substituted thiomorpholin-3-ones (2-
STMOs) figured as pharmacophores in the ligand-based drug design [6]. Owing to three potential binding sites it
is used as a spacer for construction of metal-organic coordination polymers with metal ions, like copper(II) [7],
cadmium (II) and zinc(II) [8]. Moreover, it was shown that its thiocarboxylate salt displays biological activity
which is based on stimulation of the γ–globin promoter and increase of hemoglobin production [9]. It has also
been reported that Hbta undergoes the direct photolysis in acetonitrile solution, in which the main process is the
photoinduced cleavage of C−S bond [10]. Therefore, it was found that Hbta plays crucial roles in the following
processes: (i) acts as a photoinitiating system (electron donor) in photoinduced free-radical polymerization in
conjunction with 4-carboxybenzophenone as a sensitizer [11]; (ii) acts as the electron-donating quencher in the
primary photochemical process of 4-carboxybenzophenone used as the triplet sensitizer [12].
The literature reports various methods of Hbta preparation [1, 13-19]. Among them, the efficient method is
S-alkylation of thioglycolic acid by benzyl chloride in the presence of silica at room temperature which gives the
yield 71 % for Hbta [13]. The other routes of Hbta synthesis involve the reaction between: (i) benzyl chloride
* Corresponding author. E-mail address: j.sienkiewicz-gromiuk@poczta.umcs.lublin.pl (J. Sienkiewicz-
Gromiuk)
1

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and sodium salt of ethyl-thioglycolate in the presence of ethanol-water solution [1]; (ii) benzyl bromide and
thioglycolic acid [14]; (iv) benzylthiol and chloroacetic acid [15]; (v) benzyl alcohol and S-carboxymethyl-
hydrogen thiosulfate [16]; (vi) benzyl alcohol and thioglycolic acid [17]; (vii) O-alkyl-N,N′-dicyclohexylisourea
and thioglycolic acid [18]; (viii) S-benzylithiouronium chloride and chloroacetic acid [19].
Despite numerous studies of Hbta carried out for ages, its crystal structure was not described. This paper
presents a three-step route of Hbta synthesis consisting in: (a) reaction of benzyl chloride and thiourea resulting
in isothiouronium chloride; (b) transformation of isothiouronium salt into benzylthiol; (c) conversion of
benzylthiol into (benzyl)thioacetic acid. Though the above presented method includes three reactions known
individually in the literature, their combination into the above reaction sequence proved to be a very effective
synthesis method of completely pure Hbta. Moreover, the acid synthesized in the form of white powder was
successfully re-crystallized and the prepared single crystals were exploited for determination of the Hbta crystal
structure. Besides the SC XRD technique, the compound was analyzed using: elemental analysis, melting point
1
measurement, XRPD analysis, ATR-FTIR and H and 13C NMR spectroscopy as well as thermal analysis
(TG/DSC).
2. Experimental section
2.1. Materials and general methods
All chemicals and solvents used in the synthesis were obtained from a commercial source and used without
further purification.
Melting point was measured on a SANYO Gallenkamp MPD 350 BM 3.5 melting point apparatus and was
uncorrected.
Elemental analysis for carbon, hydrogen and sulphur was performed by means of a Perkin Elmer 2400
Series II CHNS/O elemental analyzer.
The X-ray powder diffraction (XRPD) data for powdered single-crystals were collected at ambient
temperature on an Empyrean PANalytical automated diffractometer with CuKα radiation (λα = 1.54187 Å) via
continuous scan with a step size of 0.02626 ° over the scattering angular range 2θ = 3−90 °. Indexation of the
recorded diffraction profile and calculation of unit cell parameters were made using the DICVOL04 [20] and
TREOR90 [21-23] programs as implemented in the FullProf Suite software package [24]. The reliability of the
calculated unit cell was estimated by the figure of merit M(n) [25] and F(n) [26]. The indexed powder X-ray
diffraction pattern was compared with the XRD pattern simulated by the Mercury software [27] on the basis of
single crystal X-ray data.
The attenuated total reflectance ATR-FTIR spectrum was recorded in the range 4000–600 cm-1 employing a
Nicolet 6700 FTIR spectrophotometer equipped with a universal ATR attachment with a ZnSe crystal.
One-dimensional NMR spectra were registered with a Bruker Avance 300 FT-NMR spectrometer operating
at 300 and 75.5 MHz for 1H and 13C, respectively. The 1H and 13C chemical shifts were collected at 25 °C in the
DMSO-d6 relative to an internal standard of TMS. The DEPT (Distorsionless Enhancement by Polarisation
Transfer) technique was applied for determination of the number of hydrogen atoms directly linked to carbon
atoms. The DEPT spectra were registered for the width of 45, 90 and 135 ° pulse sequences.
The thermal behaviour was investigated with a Setaram Setsys 16/18 thermal apparatus, recording the TG,
DTG and DSC curves. The sample of 7.96 mg was heated in a ceramic crucible between 30 and 750 °C in the
flowing air atmosphere with a heating rate of 10 °C min-1.
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2.2. Synthesis and growth
The general method, involving a three-step reaction sequence, adopted for the preparation of Hbta is
specified in Fig. 1. The first stage of preparation consisted in the reaction of benzyl chloride with thiourea in the
presence of ethanol-water solution, which allowed to produce the first intermediate product, namely
isothiouronium chloride (Fig. 1a). Next, the obtained isothiouronium salt was subjected to the alkaline
hydrolysis giving benzylthiol (benzyl mercaptan) as the hydrolisate (Fig. 1b). Lastly, benzylthiol was condensed
with chloracetic acid in the alkaline environment to Hbta as the final product (Fig. 1c). The applied reactions
which successively formed isothiouronium chloride [28-32], benzylthiol [33] and finally (benzylthio)acetic acid
[15] are the modifications of literature methods. Crystallization of crude product from ethanol and water (50:50)
gave pure Hbta in the form of white powder (6.3 g, 78 % yield). The full description of individual stages of the
synthesis strategy is given in detail in the Appendix A: Supplementary Material.
A saturated solution of Hbta was prepared from the pure synthesized material, using methanol as solvent,
and the filtered solution was allowed to evaporate at room temperature in order to enhance the purity of the
material and to obtain single crystals of Hbta suitable for structural studies. The colourless plate crystals suitable
for single-crystal diffraction study were isolated after one week.
Data for Hbta: Yield (6.3 g, 78 %); M. p.: 63.5−65 ºC (lit. M.p.: 64 ºC [1], 62−63 ºC [14]); Anal. Calcd. for
C9H10O2S (182.24): C, 59.31; H, 5.53; S, 17.60. Found: C, 59.43; H, 5.59; S, 17.44; ATR-FTIR (cm-1): 3060,
3028, 2954, 2918, 2667, 2581, 1694, 1451, 1430, 1308, 1132, 1070, 931, 758, 680; 1H NMR (300 MHz, DMSO-
d6): δ 12.61 (s, 1H), 7.22–7.36 (m, 5H), 3.81 (s, 2H), 3.11 (s, 2H); 13C NMR (75.5 MHz, DMSO-d6): δ 171.30,
137.76, 128.97, 128.43, 127.01, 35.44, 32.62.
2.3. Single crystal X-ray analysis
The crystallographic measurements of (benzylthio)acetic acid (Hbta) were performed on an Oxford
Diffraction Xcalibur CCD diffractometer with the graphite-monochromatized Mo Kα radiation. The data were
collected at 295(2) K using the ω scan technique, with an angular scan width of 1.0°. The CRYSALIS suit of
programs [34] was used for data collection, cell refinement and data reduction. A multi-scan absorption
correction was applied. The structure was solved by the direct methods using SHELXS-97 and refined by the
full-matrix least-squares on F2 using SHELXL-97 [35]. All non-H atoms were refined with anisotropic
displacement parameters. All H atoms were found in the difference-Fourier maps and refined with isotropic
displacement parameters.
3. Results and discussion
3.1. X-ray crystallography
The crystallographic data and structure refinement details for Hbta are given in Table 1. Single-crystal X-ray
analysis confirmed that the title compound crystallizes in the monoclinic space group P21/c with one Hbta
molecule in the asymmetric unit of the crystal (Fig. 2). The acid molecule adopts bent conformation in the solid
state, with sulphur S1 atom being ±sc oriented towards phenyl C9 and carboxyl O2 atoms. As follows from the
torsion angle C1−C2−S1−C3 (Table 2), the carboxylic group of the acid is ±sc as regards the benzyl moiety and
forms a dihedral angle of 22.2(3) ° with the best plane of the benzyl subunit.
3

The most characteristic featureAofCthCeEstPudTieEdDcryMstaAl iNs UtheSpCreRseInPceTof molecular dimers formed by the
inversion related molecules connected by strong O2−H2o···O1(a) [symmetry code: 1-x, 1-y, 1-z] hydrogen bonds
(d)
(Fig. 3a, Table 3). The adjacent dimers are linked via C3−H3a…πphen interactions (dC3…πcent = 3.512(2) Å,
dH3a…πcent = 2.64(2) Å, θC8-H3a…πcent = 149(2) °; symmetry code: 2-x, -y, 1-z) and further by weak C2−H2a…O2(b)
(symmetry code: 1-x, y-1/2, 3/2-z) and C7−H7…S1(c) (symmetry code: x, -y-1/2, z-1/2) hydrogen bonds into the
complex 3-D supramolecular architecture (Fig. 3b).
3.2. Structure of polycrystalline product
The phase purity and crystalline nature of Hbta were established on the basis of X-ray powder diffraction
(XRPD) analysis. The well defined Bragg’s peaks at particular 2θ angles in the experimental and simulated
powder diffraction profiles are presented in Fig. 4. Both patterns fit well with each other which confirms that the
studied material represents a pure phase with good crystallinity. The Hbta crystallizes in the monoclinic crystal
system with the unit cell parameters listed in Table 4. Additionally, these calculated values of lattice parameters
show very good match with the data (Table 1) determined from single-crystal X-ray diffraction.
3.3. ATR-FTIR spectral analysis
ATR-FTIR spectroscopy was used for the detection of functional groups of the synthesized material. The
recorded spectrum of Hbta is shown in Fig. 5. The broad absorption band in the region 3300 to 2400 cm-1 is due
to the overlapping of hydroxyl ν(OH) stretching vibrations (2667 and 2581 cm-1), aromatic ν(CarH) stretching
vibrations (3060, 3028 and 3002 cm-1) and methylene ν(CH2) stretching asymmetric (2954 cm-1) and symmetric
(2918 cm-1) vibrations. This broad band observed in the high frequency region confirms the dimeric association
in Hbta crystals. This dimeric association is the result of formation of strong and linear hydrogen bonds between
two carboxyl groups from the adjacent molecules of Hbta. Other specific bands of the organic acid function can
be determined, such as ν(C=O) stretch mode at 1694 cm-1, in-plane deformation β(COH) band at 1430 cm-1,
ν(C−O) stretching band at 1308 cm-1 and out-of-plane deformation γ(COH) band at 931 cm-1. The molecule of
Hbta contains one benzene ring, so in the spectrum some aromatic bands were found. The stretching ν(CarCar)
ring modes are located at 1599, 1493 and 1451 cm-1, the in-plane deformation β(CarH) vibrations are situated at
1132 and 1070 cm-1, whereas the intensive bands observed at 758 and 680 cm-1 indicate the out-of-plane bending
γ(CarH) vibrations which are characteristic of monosubstituted aromatic ring [36].
3.4. 1H and 13C nuclear magnetic resonance
1
The protons and carbons were assigned by their chemical shift (δ) from H and 13C NMR spectra (Fig 6)
recorded in the DMSO-d6 solution. In the case of carbon signals, their respective assignments were supported by
the DEPT experiments [36] (Figs S1-S3; Appendix A: Supplementary Material). The collected spectroscopic
data of Hbta are summarized in Table 5.
1
As follows from the H NMR profile (Fig. 6a), the four conspicuous proton signals derived from Hbta
confirm four different proton environments. The very weak and broadened signal observed at 12.61 ppm reflects
the presence of intermolecularly H-bonded carboxylic HA proton [36, 38]. The proton signal appearing from 7.22
to 7.36 ppm originates from five aromatic HB protons of phenyl moiety. The singlet found at 3.81 ppm came
from HC methylene hydrogens of benzyl part of Hbta, whereas the second singlet centered at 3.11 ppm was
assigned to the methylene HD protons from the acetic system. Apart from the proton signals derived from Hbta,
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the other two singlets at 3.34 and 2.51 ppm were visible. These peaks constituted the remanent proton signals
stemmed from water protons and not completely deuterized methyl protons of DMSO molecules acting as
pollutants of the applied solvent in the form of deuterized DMSO-d6.
As can be seen from Fig. 1, there is carbon atom bound to electronegative oxygen atoms in the molecule of
Hbta. Thus, the peak situated in the 13C NMR spectrum (Fig. 6b) in the deshielded region at 171.3 ppm as well
as its absence in each DEPT sequence (Figs S1-S3) pinpoints the carboxylic C1 carbon atom. The aromatic
carbons give signals with the chemical shift values in the range 100–150 ppm [36]. The four signals were
observed between 127.01 and 137.76 ppm due to the four types of magnetically and chemically equivalent
aromatic carbons. Amid them, one clearly separated carbon signal with the highest value of chemical shift being
137.76 ppm corresponds to the nonprotonated aromatic carbon atom C2 which is not active in any DEPT
measurements. The other three signals observed at slightly lower values of chemical shift, that is: 128.97, 128.43
*
and 127.01 ppm, are attributed to the three types of equivalent and protonated aromatic C3 , C4* and C5 carbon
atoms of phenyl ring, respectively. The protonation of C3, C4 and C5 atoms is also confirmed by the DEPT
profiles in which the signals derived from them are observed as plus active. The two singlets seen at 35.44 and
32.62 ppm came from the methylene carbon atoms C6 and C7, respectively. The seven-component signal located
between 38.66 and 40.33 ppm is derived from not completely deuterized molecules of DMSO.
3.5. TG/DSC investigations
The information about thermal stability of Hbta crystals was acquired through thermogravimetric and
differential scanning calorimetry. The TG, DTG and DSC curves for Hbta are presented in Fig. 7. The analyzed
material exhibits good resistance to thermal decomposition up to about 150 °C. Additionally, the plateau on the
registered TG curve between 30 and 150 °C attests anhydrous character of Hbta. The sharp endothermic peak
found on the DSC curve at 64 °C indicates the melting point of the pure acid which is compliant with the
measured melting point in the range 63.5−65 °C. The investigated material undergoes exothermic decomposition
in a single stage between 150 and 300 °C which is confirmed by only one exothermic peak visible on the DSC
curve around 285 °C. The decomposition process of Hbta is probably overlapped with another endothermic
melting process observed on the DCS curve as a broadened peak with the top situated at 275 °C.
4. Conclusions
The pure and crystalline (benzylthio)acetic acid was successfully synthesized from thiourea and benzyl
chloride via thiouronium salt and benzylthiol as intermediates. The well-shaped crystals of (benzylthio)acetic
acid were grown by the slow evaporation technique using methanol as a solvent. The obtained crystals were
subjected to various characterization studies, including elemental analysis, melting point measurement, X-ray
1
single and powder diffraction, ATR-FTIR, H and 13C NMR and thermal analysis. Single crystal X-ray analysis
provided detailed information on molecular and crystal structure of the acid. Very good fit between the simulated
and experimental powder diffraction patterns confirmed the phase purity and good crystalline quality of the
1
sample. The appearance of four proton and seven carbon signals in the recorded H and 13C NMR spectra
unambiguously proved the structure of Hbta. The presence of hydrogen-bonded carboxylic groups derived from
the neighbouring molecules of Hbta is reflected in the registered ATR-FTIR spectrum. Thermal study indicates
that the analyzed material is resistant to thermal degradation up to about 150 ºC and the melting point is 64 ºC.
5

Appendix A: Supplementary MateAriaCl CEPTED MANUSCRIPT
Crystallographic data for the structure reported in this paper has been deposited with the Cambridge
Crystallographic Data Centre as supplementary publication No. CCDC: 1002053. Copies of available materials
can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (fax: (+44)
1223-336-033; e-mail: data_request@ccdc.cam.ac.uk or www: http//www.ccdc.cam.ac.uk/data_request/cif).
Supplementary data associated with this article can be found, in the online version, at …
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36 R.M. Silverstein, F.X. Webster, Spectrometric Identification of Organic Compounds, John Wiley & Sons, New York, 1998.
37 J. Fröhlich, F. Sauter, V. Milata, 13C NMR of thia- or aza-substituted butyric acid derivatives, Magn. Reson. Chem. 39 (2001) 113-114.
38 M. Hesse, H. Meier, B. Zeeh, Spectroscopic Methods in Organic Chemistry, 2nd Edition, Thieme Medical Publishers Inc., 2007.
Figure captions:
Fig. 1. Three-step synthesis scheme of Hbta from benzyl chloride and thiourea.
Fig. 2. Molecular structure of Hbta in the crystal with the atom numbering scheme. Thermal ellipsoids are drawn
at 50% probability level.
Fig. 3. (a) Intermolecular interactions in Hbta; (b) crystal packing in view along the b-axis. Symmetry codes: (a) -
x+1, -y+1, -z+1; (c) x, -y-1/2, z-1/2; (d) -x+2, -y, -z+1; (e) -x+1, -y, -z+1.
Fig. 4. Experimental and simulated XRPD patterns of Hbta.
Fig. 5. ATR-FTIR spectrum for Hbta.
Fig. 6. 1H NMR (a) and 13C NMR (b) spectra of Hbta dissolved in DMSO-d6.
Fig. 7. Thermal profile of Hbta containing TG, DTG and DSC thermal curves.
7

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Table 1 Single-crystal data and structure refinement details for Hbta.
Empirical formula
Formula weight
Temperature [K]
Wavelength [Å]
Crystal system
Space group
C9H10O2S
182.23
295(2)
0.71073
monoclinic
P21/c
Unit cell dimensions
a [Å]
b [Å]
c [Å]
α [°]
10.0453(7)
8.0579(6)
11.4830(7)
90.00
β [°]
100.464(6)
90.00
914.0(1)
γ [°]
V [Å3]
Z
4
Calculated density [g cm-3]
Absorption coefficient [mm-1]
F(000)
1.324
0.309
384
Crystal size [mm]
θ range [°]
0.56 × 0.26 × 0.08
3.26–27.47
2090 (0.02)
1.105
R1=0.0397; wR2=0.0973
R1=0.0504; wR2=0.1085
Unique reflections (Rint)
Goodness-of-fit on F2
Final R indices [I>2σ(I)]
R indices (all data)
Largest diff. peak and hole [e Å-3] 0.36 and -0.27
Table 2 Selected bond lengths, angles and torsion angles [Å, °] for Hbta.
1.242(2)
1.302(2)
1.499(2)
1.817(2)
1.816(2)
1.511(2)
C1−O1
C1−O2
C1−C2
S1−C2
S1−C3
C3−C4
124.1(2)
120.8(1)
115.0(1)
108.3(1)
100.6(1)
114.2(1)
O1−C1−O2
O1−C1−C2
O2−C1−C2
C1−C2−S1
C2−S1−C3
S1−C3−C4
-78.9(2)
-54.1(2)
-75.6(1)
-66.0(1)
O2−C1−C2−S1
S1−C3−C4−C9
C1−C2−S1−C3
C2−S1−C3−C4
Table 3 Hydrogen-bonding geometry for Hbta [Å, °].
D-H...A
d(D-H) d(H...A) d(D...A)
0.92(3) 1.69(3) 2.613(3)
0.90(2) 2.70(2) 3.459(2)
0.98(2) 3.00(2) 3.807(2)
DH...A
178(2)
143(2)
140(2)
O2−H1o...O1a
C2−H2a...O2b
C7−H7...S1c
Symm. codes: (a) -x+1, -y+1, -z+1; (b) -x+1, y-1/2, -z+3/2;
(c) x, -y-1/2, z-1/2;

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Table 4 Lattice parameters for polycrystalline form of Hbta.
Lattice
parameters
System
a [Å]
b [Å]
c [Å]
Powder XRD data refined
by DICVOL04 [20]
Powder XRD data refined
by TREOR90 [21-23]
monoclinic
10.2402
8.0775
11.5367
90
monoclinic
10.2456
8.0823
11.5396
90
α [°]
β [°]
99.804
90
941.63
99.804
90
940.32
γ [°]
V[Å3]
M(20) [25] 38.9
31
F(20)
F(n) [26]
75.4(0.0063, 42)
F(42) = 30.9(0.0055, 247)
60.(0.0080, 42)
F(42) = 28.(0.0063, 244)
F(n) – number of indexed peaks
Table 5 Experimental 1H and 13C NMR chemical shifts δ [ppm] for Hbta.
δ (300 MHz,
DMSO-d6)
δ (300 MHz,
CDCl3) [1]
Group
fragment
1H
A
B
C
D
12.61
7.22–7.36
3.81
10.20
–COOH
–PhH
7.35
3.85
3.15
δ (50.3 MHz,
CDCl3)[37]
176.8
136.8
129.2
128.6
127.4
36.3
–CH2Ph
–CH2COOH
Group
fragment
–COOH
–Ph
–Ph
–Ph
–Ph
–CH2Ph
–CH2COOH
3.11
δ (75.5 MHz,
DMSO-d6)
171.30
137.76
128.97
128.43
127.01
35.44
13C
1
2
3*
4*
5
6
7
32.62
31.9

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Hightlights
ꢀ
ꢀ
ꢀ
ꢀ
Synthesis and crystal growth of (benzyl)thioacetic acid (Hbta) crystals.
The first full structural description of Hbta crystals.
Spectroscopic (ATR-FTIR and NMR) characterization of title material.
Thermal stability study of the compound.