Mesomorphic behaviour of N-benzoyl-N′-aryl thioureas liquid crystalline compounds

Article abstract of DOI:10.1016/j.molstruc.2010.11.037

A series of N-benzoyl-N′-aryl thiourea derivatives bearing alkoxy groups in terminal positions have been prepared and investigated for their potential liquid crystals properties. It was found that only the compounds which have only two alkoxy chains show calamitic mesomorphic behaviour, with nematic, smectic A and C phases being displayed. The type and stability of these mesophases are greatly influenced by the alkyl chain length. Successive introduction of additional alkoxy groups on the benzoyl moiety led to a significant decrease of the clearing points and suppression of the mesogenic character. Using of branched alkyl chain, 2-ethyl-hexyl, instead of normal alkyl group, led to the disappearance of mesogenic behaviour together with the lowering of the clearing temperature. The influence of chain length and number of chains is discussed.

Full text of DOI:10.1016/j.molstruc.2010.11.037

Journal of Molecular Structure 987 (2011) 1–6
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Mesomorphic behaviour of N-benzoyl-N0-aryl thioureas liquid
crystalline compounds
Monica Ilißs a, Madalina Bucos a, Florea Dumitraßscu b, Viorel Cîrcu a,
⇑
a Dept. of Inorganic Chemistry, University of Bucharest, 23 Dumbrava Rosie St., Sector 2, Bucharest 020464, Romania
b Centre of Organic Chemistry ‘‘C.D. Nenitzescu’’, Romanian Academy, Spl. Independentei 202B, Bucharest 060023, Romania
a r t i c l e i n f o
a b s t r a c t
A series of N-benzoyl-N0-aryl thiourea derivatives bearing alkoxy groups in terminal positions have been
prepared and investigated for their potential liquid crystals properties. It was found that only the com-
pounds which have only two alkoxy chains show calamitic mesomorphic behaviour, with nematic, smec-
tic A and C phases being displayed. The type and stability of these mesophases are greatly influenced by
the alkyl chain length. Successive introduction of additional alkoxy groups on the benzoyl moiety led to a
significant decrease of the clearing points and suppression of the mesogenic character. Using of branched
alkyl chain, 2-ethyl-hexyl, instead of normal alkyl group, led to the disappearance of mesogenic behav-
iour together with the lowering of the clearing temperature. The influence of chain length and number
of chains is discussed.
Article history:
Received 29 September 2010
Received in revised form 15 November 2010
Accepted 15 November 2010
Available online 23 November 2010
Keywords:
N-benzoyl thiourea
Liquid crystals
Mesophase
Smectic
Ó 2010 Elsevier B.V. All rights reserved.
Nematic
1. Introduction
In this work we present a systematic study of the influence of
the alkyl chain length, number and position of the alkoxy groups
The N-benzoyl thiourea derivatives represent one of the most
investigated classes of ligands in the coordination chemistry as
they possess very strong donor groups (carbonyl and thioamide)
that can bind to various metal ions. It is well known that such com-
pounds, in particular N,N-dialkyl-N0-benzoyl thioureas, react with
transition metals either in monoanionic bidentate form by depro-
tonation forming neutral homoleptic complexes with S, O – coordi-
nation or in neutral form only through S atom [1].
These derivatives have found many important applications, for
example: biological activity [2], solvent extraction of metal ions
[3], especially platinum group metals, and, recently, they have
been used in the design of liquid crystalline materials [4–6], both
in purely organic liquid crystals, simple or connected to a ferrocene
moiety, or metal-containing liquid crystals – metallomesogens. Re-
cently, we reported the use of simple N-benzoyl thiourea deriva-
tives as co-ligands in luminescent platinum(II) 2-phenylpyridine
complexes [7] or in ortho-metallated palladium and platinum(II)
complexes which show liquid crystals properties [8]. Few exam-
ples of N-benzoyl-N0-aryl thiourea derivatives substituted with ter-
minal alkoxy groups in para positions at the both ends of the
molecule were reported previously by us [6] and by Seshadri
et al. [5]. These compounds were found to exhibit nematic, smectic
A and C phases, depending on the alkyl chain length.
as well as branching of alkyl chain on the mesomorphic behaviour
of a series of N-benzoyl-N0-aryl thiourea derivatives with the aim
to use further such compounds as ancillary ligands in the organo-
metallic chemistry of platinum(II) and palladium(II) with imine
type ligands. This is based on the fact that this class of ligands is
very much appealing to be used in the design of metal-containing
liquid crystals as they can be easily prepared to provide a large col-
lection in order to tailor the mesogenic or photophysical properties
of the metallomesogens.
2. Results and discussion
The availability of a large number of carboxylic acids derivatives
through the O-alkylation reaction with different alkyl bromides of
the corresponding starting material (methyl 4-hydroxybenzoate,
methyl 3,5-hydroxybenzoate or ethyl gallate) prompted us to syn-
thesize a series of BTU derivatives in which the benzoyl fragment
contains different number of alkoxy groups while keeping only
one alkoxy group on the thioureic fragment. Such approach, the in-
crease of the number of alkoxy groups at the periphery of the mol-
ecule, proved to be very successful in the design of polycatenar
materials that can display both rod or disk-like behaviour, in partic-
ular the tetracatenar mesogens, where the number and position of
alkoxy groups has a great influence on the mesogenic behaviour [9].
The synthetic procedure used to prepare the BTU compounds is
depicted in Scheme 1. These N-benzoyl-N0-aryl thiourea deriva-
⇑
Corresponding author.
E-mail address: viorel_carcu@yahoo.com (V. Cîrcu).
0022-2860/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2010.11.037

2
M. Ilißs et al. / Journal of Molecular Structure 987 (2011) 1–6
R1
R1
H(O)
H(O)
CnH2n+1Br
HCl
COOCH3
R2
COOH
R2
COOCH3
C2H5OH
K2CO3
R3
R3
H(O)
acetone
R1
R1
R3
H2N
O
CnH2n+1
O
KSCN
SOCl2
CONCS
R2
R2
acetone
CH2Cl2
Cl
acetone
R3
R1
R2
N
H
N
H
O
CnH2n+1
O
S
R3
1 (R1 = R3 = H, R2 = -OCmH2m+1; n = 1; m = 6)
2 (R1 = R3 = H, R2 = -OCnH2n+1; n = 6, a; n = 8, b; n = 10, c; n = 12, d; n = 14, e; n = 16, f)
3 (R1 = R3 = -OCnH2n+1, R2 = H; n = 12)
4 (R1 = R2 = -OCnH2n+1, R3 = H, n = 10)
5 (R1 = R2 = R3 = -OCmH2m+1; n = 8; m = 12, a; m = 16, b)
6 (R1 = R3 = H, R2 = 2-ethyl-hexyl; n = 8)
Scheme 1. Preparation of N-benzoyl-N0-aryl thiourea derivatives (BTU).
tives were obtained in good yields as white or off-white microcrys-
talline solid products, which are stable under normal conditions.
These compounds were characterized by elemental analysis, IR,
1H and 13C NMR spectroscopy while their liquid crystalline proper-
ties were investigated by DSC and polarizing optical microscopy.
The acid chlorides were prepared from the corresponding car-
boxylic acid and thionyl chloride and were used in the next step
without further purification. The entire procedure is similar to
the one used for the synthesis of simple N-benzoyl thiourea com-
pounds and comprises the reaction between acid chloride and
KSCN in dry acetone to form the corresponding isothiocyanate
derivatives that further reacts with different anilines to give the fi-
nal BTU products [10]. The formation of these products can be eas-
ily monitored by the 1H NMR spectra where two singlets, one in
the range 12.48–12.37 ppm and a second one in the range 9.02–
8.98 ppm, which can be assigned to the two NH groups, can be
seen. The first one was assigned to the NH proton located between
the thiocarbonyl group and benzene ring while the second one was
assigned to the NH proton located between the carbonyl and thio-
carbonyl groups. This assignment is also based on the fact that
when these type of ligands bind to metal ions in monoanionic
bidentate form, the latter signal disappears in the corresponding
1H NMR spectra of metal complexes. The other signals assigned
to aromatic protons show the normal splitting pattern correspond-
ing to 1,4-, 1,3,4-, 1,3,4,5-substitution of the aromatic ring. The IR
spectra show the expected absorption bands attributed to mNAH
in the range 3200–3400 cmꢀ1 and to mC@O at ꢁ1670 cmꢀ1. Three
other strong absorbtion bands can be found in the regions 1500–
1510 cmꢀ1, 1240–1250 cmꢀ1 and 1145–1155 cmꢀ1 which were as-
signed to a combination of mCAN and mphenyl stretching frequencies
[11].
3. Thermal behaviour
The new compounds were investigated for their potential liquid
crystalline properties by a combination of hot stage polarizing
optical microscopy and differential scanning calorimetry (DSC).
The transition temperatures and the corresponding enthalpies
are presented in Table 1. The assignment of the mesophases was
made based on their optical texture and several examples are pre-
sented in Figs. 4–7 [12].
The nematic phase was evidenced based on its marbled or
threaded texture which flashed when subjected to exterior
mechanical stress applied on the cover slip. An example of such a
texture can be seen in Fig. 4. The smectic A phase could be detected
based on the typical focal-conic texture displayed (Fig. 7) accompa-
nied by black homeotropic regions that, indeed confirm the iden-
tity of this mesophase. Compounds 2b and 2c also showed a
smectic C phase that was separated from a previous SmA phase.
This transition could not be evaluated from the DSC trace but from
polarizing optical microscopy observations when the previous tex-
ture of SmA phase transforms into a broken focal-conic texture
typical for SmC phase (Fig. 7). The SmC phase that was isolated
straight from the isotropic state (compounds 2d–f) could be de-
tected by the typical appearance of the broken focal-conic texture
and accompanied sometimes by gray regions of Schlieren textures
(Figs. 5 and 6).
Now, if we consider the first group of compounds, 1 and 2a–f,
bearing only two alkoxy groups in terminal position, it is very clear
that the mesomorphic behaviour is dominated by the alkyl chain
length. The nematic phase is displayed only by the compounds
having short alkyl chains (methoxy or hexyl) and this phase is
strongly destabilized as it has only a monotropic character.

M. Ilißs et al. / Journal of Molecular Structure 987 (2011) 1–6
3
Table 1
10
Transition temperatures and enthalpy changes for N-benzoyl-N0-aryl thiourea
2°C/min
5°C/min
10°C/min
derivatives.*
0
-10
-20
-30
-40
-50
-60
-70
Compound
1
Transition
Temperature (°C)
D )
H (kJ molꢀ1
Cr–Cr0
Cr0–I
113
116
15.6
27.9
20°C/min
(I–N)
(N–Cr)
(102)
(86)
(0.6)
(39.4)
30°C/min
2a
2b
Cr–I
(I–N)
(N–SmA)
(SmA–Cr)
118
48.2
(1.8)
(0.3)
(42.3)
(113)
(105)
(95)
Cr –Cr0
Cr0–SmA
SmA–I
97
115
128
2.9
42.3
5.9
I–SmA
127
6.1
20
30
40
50
60
70
(SmA–SmC)**
(SmC–Cr)
(104)**
(102)
T/°C
(39.3)
2c
Cr–SmA
SmA–I
113
128
50.4
7.6
Fig. 2. First cooling traces at various cooling rates of compound 5b.
I–SmA
122
7.5
(SmA–SmC)**
(SmC–Cr)
(118)**
(93)
(55.9)
2d
2e
2f
Cr–SmC
SmC–I
I–SmC
104
121
121
90
32.6
5.9
6.2
70
60
50
SmC–Cr
34.2
Cr–SmC
SmC–I
I–SmC
102
115
115
89
54.6
10
10
30°C/min
40
30
20
10
0
SmC–Cr
54.1
Cr–SmC
SmC–I
I–SmC
108
117
116
96
64.3
11.8
12
20°C/min
SmC–Cr
63.2
10°C/min
5°C/min
2°C/min
3
4
Cr–I***
47
84.1
Cr–I
I–Cr
94
81
53.8
52.5
30
40
50
60
70
5a
Cr–I
I–Cr
51
24
91.9
90.2
T/°C
5b
6
Cr–Cr0
Cr0–I
Cr–I
46
60
104
91
115.3
9
42.5
42.4
Fig. 3. Second heating traces at various heating rates of compound 5b.
I–Cr
*
Parentheses denote a monotropic transition.
This transition was evidenced only by polarizing optical microscopy.
Compound 3 on cooling stays in the isotropic liquid state.
**
***
80
70
60
50
40
30°C/min
30
20
10
0
20°C/min
Fig. 4. The nematic phase of compound 2a recorded on cooling from the isotropic
state at 112 °C.
10°C/min
5°C/min
2°C/min
Compound 2a having hexyl chain as terminal groups show an addi-
tional SmA phase with the same monotropic behaviour. On going
from hexyl to octyl chain there is a significant change of the mes-
ogenic character. The monotropic nematic phase is replaced by an
enantiotropic SmA phase and an additional monotropic SmC phase
30
40
50
60
70
T/°C
Fig. 1. First heating traces at various heating rates of compound 5b.

4
M. Ilißs et al. / Journal of Molecular Structure 987 (2011) 1–6
Fig. 5. Microphotograph showing the broken focal-conical texture of the SmC phase
of compound 2e recorded on cooling at 107 °C.
Fig. 7. Polarized light optical microphotographs of compound 2b, as observed on
cooling: (a) smectic A phase at 115 °C and (b) the smectic C phase at 104 °C (200ꢂ).
the exothermic peak to a transition to liquid crystalline state, addi-
tional DSC measurements were carried out at various heating–
cooling rates: 2 °C/min, 5 °C/min, 10 °C/min, 20 °C/min and 30 °C/
min. The first heating traces are shown in Fig. 1 while the first cool-
ing traces and the second heating traces for compound 5b recorded
at various heating–cooling rates are shown in Figs. 2 and 3, respec-
tively. Indeed, the first endothermic peak becomes bigger while the
second endothermic peak would become smaller with elevating
heating rate – a typical double melting behaviour. On the other
hand, as can be seen in Fig. 3, the exothermic peak between the
two endothermic peaks on the second heating DSC trace increase
with slowing down the heating rate, which once again confirm
the double melting behaviour of compound 5b [14].
It is well known that the use of branched alkyl chain leads to a
decrease of packing efficiency with immediate consequence on
melting and clearing temperatures [13]. Introducing the branched
alkyl chain in the molecule has a considerable effect on the thermal
behaviour of compound 6. Thus, the clearing point drops by nearly
24 °C by comparison with the unbranched analogue, compound 2b.
On cooling from the isotropic state, compound 6 starts crystallizing
at 91 °C, ruling out the formation of any mesophase at lower tem-
perature due to supercooling process.
Fig. 6. The SmC phase of compound 2d at 112 °C (200ꢂ).
for compound 2b or an enantiotropic SmC phase for compound 2c.
For longer alkyl chains (12, 14, and 16) only an enantiotropic SmC
phase could be seen. Such behaviour is in a total agreement with a
normal influence of the alkyl chain length on the mesogenic prop-
erties of the calamitic materials when the chain length increase
leads to an increase of the smectic tendency in the detriment of
the nematic phase [13]. Moreover, the melting points of com-
pounds 2b–f which show enatiotropic behaviour follow the normal
trend, e.g. melting points reduced by increasing the alkyl chain
length on going from n = 8 (2b) to n = 14 (2e) and an increase of
melting points, ca. 6 °C, on going from n = 14 (2e) to n = 16 (2f)
as a consequence of excessive van der Waals intermolecular forces
of attraction [13].
A significant drop of clearing temperature, between 60 and
75 °C, as well as a total suppression of liquid crystal properties oc-
curs for compounds bearing three or four alkoxy chains (com-
pounds 3, 4, 5a, b) irrespective of their number and disposition
on the benzoyl moiety. This behaviour can be explained in terms
of molecular anisotropy by taking into account that the molecular
breadth is larger when additional alkoxy groups are introduced in
the molecule and so the molecular breadth to length ratio is higher.
Fig. 3 shows the second heating DSC trace of compound 5b
where one exothermic peak between two endothermic peaks can
be seen. Such an appearance suggests the possibility of double
melting behaviour with two different stable crystalline forms. To
confirm such a hypothesis and to avoid any misleading to assign
4. Conclusions
A
series of N-benzoyl-N0-aryl thiourea derivatives bearing
alkoxy groups in terminal positions have been synthesized and
characterized structurally by
techniques.
a combination of spectroscopic

M. Ilißs et al. / Journal of Molecular Structure 987 (2011) 1–6
5
Their thermal behaviour was investigated by a combination of
DSC and polarizing optical microscopy and it was found that only
the compounds which have only two alkoxy chains show calamitic
mesomorphic behaviour, with nematic, smectic A and C phases
being displayed, while additional alkoxy groups on the benzoyl
moiety led to a significant decrease of the clearing points and
non-mesogenic behaviour. The stability of the smectic phase is
higher when longer alkyl chains are present in the molecule.
Branching of the alkyl chain had a great effect on the clearing
temperature as well as on thermal behaviour. Thus, the branched
analogue shows no mesomorphic properties.
tem, 3JHH = 9.0 Hz); 6.99 (2H, d, AA0XX0 system, 3JHH = 9.0 Hz); 6.92
3
3
(2H, d, AA0XX0 system, JHH = 9.0 Hz); 4.03 (2H, t, JHH = 6.5 Hz);
3
3.96 (2H, t, JHH = 6.5 Hz); 1.87–1.29 (24H, m); 0.89 (6H, m).
13C NMR: d(75 MHz, CDCl3, ppm): 178.8, 166.3, 163.7, 157.8,
130.4, 129.6, 125.8, 123.2, 114.9, 114.6, 68.5, 68.2, 31.8, 29.4,
29.3, 29.2, 29.0, 26.1, 26.0, 22.6, 14.1.
IR (KBr, cmꢀ1): 3303 (
CAN), 1246 ( Phenyl), 1154 (mC@S + m
m
NH), 2921, 2855 (
CAN).
mCH), 1673 (mC@O), 1510
(m
m
2c. White crystalline solid. Yield: 87%. Anal. Calcd. For
C34H52N2O3S(%): C, 71.8; H, 9.2; N, 4.9; Found: C, 71.5; H, 9.6; N,
4.8.
1H NMR: d(300 MHz, CDCl3, ppm): 12.48 (1H, s); 9.02 (1H, s),
3
7.84 (2H, d, AA0XX0 system, JHH = 8.9 Hz); 7.55 (2H, d, AA0XX0 sys-
5. Experimental
tem, 3JHH = 9.0 Hz); 6.99 (2H, d, AA0XX0 system, 3JHH = 9.0 Hz); 6.93
3
3
(2H, d, AA0XX0 system, JHH = 9.0 Hz); 4.04 (2H, t, JHH = 6.5 Hz);
Dichloromethane was distilled from phosphorus pentaoxide
while acetone was distilled over calcium chloride; other chemicals
were used as supplied. The IR spectra were recorded in KBr pellets
using a Bruker spectrometer. The NMR spectra were recorded on a
Varian Gemini 300 BB spectrometer operating at 300 MHz, using
CDCl3 or DMSO-d6 as solvent. 1H chemical shifts were referenced
to the solvent peak position, d 7.26 and TMS. Analysis by DSC as
carried out with Perkin–Elmer Diamond instrument using various
scanning rates after being encapsulated in aluminium pans. Two
or more heating traces were performed on each sample. The liquid
crystals properties were investigated by hot-stage POM (polarizing
optical microscopy) using Nikon 50i Pol microscope equipped
with a Linkam THMS600 hot stage and a TMS94 temperature con-
troller. Mesophases were assigned by their optical textures by
using POM.
3
3.97 (2H, t, JHH = 6.5 Hz); 1.85–1.25 (32H, m); 0.89 (6H, m).
13C NMR: d(75 MHz, CDCl3, ppm): 178.9, 166.5, 163.8, 158.0,
130.6, 129.8, 125.9, 123.4, 115.1, 114.8, 68.7, 68.4, 32.1, 29.7,
29.6, 29.5, 29.4, 29.2, 26.2, 26.1, 22.9, 14.3.
IR (KBr, cmꢀ1): 3335 (
CAN), 1247 ( Phenyl), 1154 (mC@S + m
m
NH), 2921, 2852 (
CAN).
mCH), 1673 (mC@O), 1510
(m
m
2d. White crystalline solid. Yield: 58%. Anal. Calcd. For
C38H60N2O3S(%): C, 73.0; H, 9.7; N, 4.5; Found: C, 72.7; H, 10.0;
N, 4.3.
1H NMR: d(300 MHz, CDCl3, ppm): 12.47 (1H, s); 9.00 (1H, s),
3
7.84 (2H, d, AA0XX0 system, JHH = 8.9 Hz); 7.55 (2H, d, AA0XX0 sys-
tem, 3JHH = 9.0 Hz); 6.99 (2H, d, AA0XX0 system, 3JHH = 9.0 Hz); 6.93
3
3
(2H, d, AA0XX0 system, JHH = 9.0 Hz); 4.04 (2H, t, JHH = 6.5 Hz);
3
3.96 (2H, t, JHH = 6.5 Hz); 1.85–1.30 (40H, m); 0.89 (6H, m).
13C NMR: d(75 MHz, CDCl3, ppm): 173.9, 166.5, 163.9, 158.0,
130.6, 129.8, 125.9, 123.4, 115.1, 114.8, 68.7, 68.4, 32.1, 29.7,
29.6, 29.5, 29.4, 29.2, 26.2, 26.1, 22.9, 14.3.
6. Preparation of N-benzoyl-N0-aryl thiourea derivatives
IR (KBr, cmꢀ1): 3352 (
CAN), 1246 ( Phenyl), 1154 (mC@S + m
m
NH), 2920, 2851 (
mCH), 1671 (mC@O), 1509
The following is the typical procedure for the preparation of all
BTU derivatives.
(m
m
CAN).
2e. White crystalline solid. Yield: 64%. Anal. Calcd. For
The acid chlorides were prepared by the reaction between cor-
responding carboxylic acids and thionyl chloride in freshly distilled
dichloromethane by heating under reflux for 8 h. The excess of
thionyl chloride was removed under reduced pressure and the
resulting products were used in the next step without further puri-
fication. A solution of corresponding acid chloride (5 mmol) in ace-
tone (15 mL) was added dropwise to a solution of KSCN (5 mmol)
in acetone (30 mL). The resulting mixture was stirred and heated
under reflux for 30 min. After the mixture was cooled down to
room temperature, a solution of corresponding p-alkoxyaniline
(46 mmol) in acetone (10 mL) was added dropwise for another
30 min. The mixture was further stirred at room temperature for
2 h after which 100 mL of water was added. The resulting precipi-
tate was filtered off and washed several times with water and eth-
C
42H68N2O3S(%): C, 74.1; H, 10.1; N, 4.1; Found: C, 73.9; H, 10.5;
N, 4.0.
1H NMR: d(300 MHz, CDCl3, ppm): 12.47 (1H, s); 9.01 (1H, s),
3
7.84 (2H, d, AA0XX0 system, JHH = 8.9 Hz); 7.55 (2H, d, AA0XX0 sys-
tem, 3JHH = 9.0 Hz); 6.99 (2H, d, AA0XX0 system, 3JHH = 9.0 Hz); 6.93
3
3
(2H, d, AA0XX0 system, JHH = 9.0 Hz); 4.04 (2H, t, JHH = 6.6 Hz);
3
3.96 (2H, t, JHH = 6.6 Hz); 1.85–1.30 (48H, m); 0.89 (6H, m).
13C NMR: d(75 MHz, CDCl3, ppm): 173.9, 166.5, 163.9, 158.0,
130.6, 129.8, 125.9, 123.4, 115.1, 114.8, 68.7, 68.4, 32.1, 29.7,
29.6, 29.5, 29.4, 29.2, 26.2, 26.1, 22.9, 14.3.
IR (KBr, cmꢀ1): 3225 (
CAN), 1248 ( Phenyl), 1167 (mC@S + m
m
NH), 2923, 2853 (
CAN).
mCH), 1675 (mC@O), 1507
(m
m
2f. White crystalline solid. Yield: 72%. Anal. Calcd. For
C46H76N2O3S(%): C, 74.9; H, 10.4; N, 3.8; Found: C, 74.5; H, 10.6;
anol followed by recrystallisation from
dichloromethane/ethanol.
a
mixture of
N, 3.6.
1H NMR: d(300 MHz, CDCl3, ppm): 12.45 (1H, s); 9.01 (1H, s),
3
The analytical data for compounds 1 and 2a were reported else-
where [6]. The yields, elemental analysis results as well as 1H and
13C NMR and IR data are presented below:
7.85 (2H, d, AA0XX0 system, JHH = 8.9 Hz); 7.53 (2H, d, AA0XX0 sys-
tem, 3JHH = 9.0 Hz); 6.99 (2H, d, AA0XX0 system, 3JHH = 9.0 Hz); 6.92
3
3
(2H, d, AA0XX0 system, JHH = 9.0 Hz); 4.05 (2H, t, JHH = 6.5 Hz);
2a. 1H NMR: d(300 MHz, CDCl3, ppm): 12.45 (1H, s); 9.00 (1H, s),
3.97 (2H, t, JHH = 6.5 Hz); 1.88–1.28 (56H, m); 0.91 (6H, m).
3
3
7.83 (2H, d, AA0XX0 system, JHH = 8.9 Hz); 7.53 (2H, d, AA0XX0 sys-
13C NMR: d(75 MHz, CDCl3, ppm): 173.9, 166.5, 163.9, 158.0,
130.6, 129.8, 125.9, 123.4, 115.1, 114.8, 68.7, 68.4, 32.1, 29.7,
29.6, 29.5, 29.4, 29.2, 26.2, 26.1, 22.9, 14.3.
tem, 3JHH = 8.9 Hz); 6.98 (2H, d, AA0XX0 system, 3JHH = 8.9 Hz); 6.98
3
3
(2H, d, AA0XX0 system, JHH = 8.9 Hz); 4.03 (2H, t, JHH = 6.3 Hz);
3
3.95 (2H, t, JHH = 6.3 Hz); 1.85–1.30 (16H, m); 0.91 (6H, m).
IR (KBr, cmꢀ1): 3356 (
CAN), 1255 ( Phenyl), 1153 (mC@S + m
m
NH), 2919, 2851 (
CAN).
mCH), 1671 (mC@O), 1510
IR (cmꢀ1): 3332 (
mNH), 2942, 2861 (
mCH), 1673 (
m
C@O), 1508
(m
m
(m
CAN), 1250 (
m
Phenyl), 1154 (mC@S CAN).
+
m
3. Off-white crystalline solid, Yield: 51%. Anal. Calcd. For
2b. White crystalline solid. Yield: 60%. Anal. Calcd. For
C50H84N2O4S(%): C, 74.2; H, 10.5; N, 3.5; Found: C, 74.0; H, 10.7;
C
5.9.
30H44N2O3S(%): C, 68.4; H, 7.9; N, 6.1; Found: C, 68.0; H, 8.2; N,
N, 3.3.
1H NMR (300 MHz CDCl3, ppm): d 12.37 (s, 1H); 9.01 (s, 1H);
1H NMR: d(300 MHz, CDCl3, ppm): 12.48 (1H, s); 9.02 (1H, s),
7.56 (AA0XX0 system, 2H, JHH = 9.0 Hz); 6.93 (m, 4H); 6.67 (t, 1H,
3
3
7.85 (2H, d, AA0XX0 system, JHH = 8.9 Hz); 7.55 (2H, d, AA0XX0 sys-
4JHH = 2.2 Hz); 3.98 (m, 6H); 1.80–1.26 (m, 60H); 0.88 (m, 9H).

6
M. Ilißs et al. / Journal of Molecular Structure 987 (2011) 1–6
13C NMR (75 MHz): d 178.6, 167.1, 160.9, 158.0, 133.7, 125.9,
13C NMR (75 MHz): d 179.0, 166.6, 164.1, 158.1, 130.8, 129.9,
126.0, 123.5, 115.2, 114.9, 102.4, 71.3, 68.5, 39.5, 32.0, 30.7, 29.6,
29.5, 29.3, 26.3, 24.1, 23.2, 22.9, 14.3, 11.3.
114.7, 106.6, 105.7, 68.7, 68.4, 32.1, 29.8, 29.78, 29.7, 29.5, 29.4,
29.2, 26.2, 26.1, 22.8, 14.3.
IR (KBr, cmꢀ1): 3310 (
CAN), 1244 (
m
NH), 2918, 2852 (
m
CH), 1663 (
mC@O), 1512
IR (KBr, cmꢀ1): 3310 (
CAN), 1252 ( Phenyl), 1156 (mC@S + m
m
NH), 2923, 2856 (
CAN).
mCH), 1672 (mC@O), 1509
(m
m
Phenyl), 1173 (mC@S CAN).
+
m
(m
m
4. Off-white crystalline solid. Yield 65%. Anal. Calcd. For
C44H72N2O4S(%): C, 72.9; H, 10.0; N, 3.9; Found: C, 72.7; H, 10.3;
Acknowledgments
N, 3.9.
1H NMR (300 MHz, DMSO-d6, ppm): d 9.79 (s, 1H); 7.52 (dd, 1H,
The authors acknowledge the financial support from CNCSIS –
UEFISCSU, Project Number PNII – IDEI ID_954/2007 and CEEX ET-
31.
4
3JHH = 8.4 Hz, JHH = 1.8 Hz); 7.50–7.42 (m, 3H); 6.98 (d, 1H,
3
3JHH = 8.4 Hz); 6.83 (AA0XX0 system, 2H, JHH = 8.8 Hz); 4.01–3.87
(m, 6H); 1.85–1.20 (m, 48H); 0.85 (m, 9H).
IR (KBr, cmꢀ1): 3235 (
m
NH), 2919, 2850 (
mCH), 1652 (mC@O), 1515
Appendix A. Supplementary material
(m
CAN), 1245 (mPhenyl), 1165 (mC@S CAN).
+ m
5a. White crystalline solid. Yield: 71%. Anal. Calcd. For
58H88N2O5S(%): C, 75.3; H, 9.6; N, 3.0; Found: C, 75.0; H, 9.9; N,
Supplementary data associated with this article (NMR and IR
spectra, DSC traces) can be found, in the online version, at
doi:10.1016/j.molstruc.2010.11.037.
C
2.8.
1H NMR (300 MHz, CDCl3, ppm): d 12.44 (s, 1H); 8.99 (s, 1H);
3
7.55 (d, AA0XX0 system, 2H, JHH = 9.1 Hz); 7.04 (s, 2H); 6.93 (d,
References
3
AA0XX0 system, 2H, JHH = 8.8 Hz); 4.07–3.94 (m, 8H); 1.92–1.20
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(b) P. Muhl, K. Gloe, F. Dietze, E. Hoyer, L. Beyer, Z. Chem. 26 (1986) 81;
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(m, 72H); 0.88 (m, 12H).
13C NMR (75 MHz): d 178.7; 166.9; 158.1; 153.6; 143.3;
130.5;126.3; 125.9; 114.8; 106.2; 73.8; 69.7; 68.4; 31.07; 32.0;
30.6; 30.5; 29.8; 29.8; 29.5; 29.4; 26.2; 22.8; 14.3.
IR (KBr, cmꢀ1): 3313 (
CAN), 1244 ( Phenyl), 1174 (mC@S + m
m
NH), 2918, 2851 (
CAN).
mCH), 1659 (mC@O), 1500
(m
m
5b. White crystalline solid Yield: 60%. Anal. Calcd. For
C70H124N2O5S(%): C, 76.0; H, 11.3; N, 2.5; Found: C, 75.7; H, 11.6;
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N, 2.4.
(2008) 3537;
1H NMR (300 MHz, CDCl3, ppm): d 12.44 (s, 1H); 8.98 (s, 1H);
(b) V. Cîrcu, D. Ma˘na˘ila˘-Maximean, C. Rosßu, M. Ilisß, Y. Molard, F. Dumitrasßcu,
Liq. Cryst. 36 (2009) 123;
(c) A.S. Mocanu, M. Ilis, F. Dumitrascu, M. Ilis, V. Circu, Inorg. Chim. Acta 363
(2010) 729.
3
7.55 (d, AA0XX0 system, 2H, JHH = 9.1 Hz); 7.03 (s, 2H); 6.93 (d,
3
AA0XX0 system, 2H, JHH = 9.1 Hz); 4.06–3.94 (m, 8H, d); 1.92–
1.20 (m, 96H); 0.87 (m, 12H).
[9] R.W. Date, E.F. Iglesias, K.E. Rowe, J.M. Elliott, D.W. Bruce, Dalton Trans. (2003)
1914.
[10] I.B. Douglass, F.B. Dains, J. Am. Chem. Soc. 56 (1934) 719.
[11] (a) M.S.M. Yusof, R.H. Jusoh, W.M. Khairul, B.M. Yamin, J. Mol. Struct. 975
(2010) 280;
13C NMR (75 MHz): d 178.7; 166.9; 158.1; 153.6; 130.5; 125.9;
114.8; 106.2; 102.9; 73.8; 69.7; 68.4; 33.3; 32.07; 30.5; 29.9; 29.8;
29.5; 26.2; 22.8; 14.3.
IR (KBr, cmꢀ1): 3328 (
CAN), 1251 ( Phenyl), 1172 (mC@S + m
mNH), 2919, 2851 (
mCH), 1667 (mC@O), 1513
(b) V. Cârcu, M. Negoiu, T. Rosßu, S. Sßerban, J. Therm. Anal. Calorim. 61 (2000)
935.
(m
m
CAN).
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Taylor&Francis, London and New York, 2004.
[14] (a) K. Ohta, H. Muroki, K. Hatada, I. Yamamoto, K. Matsuzaki, Mol. Cryst. Liq.
Cryst. 130 (1985) 249;
6. White crystalline solid. Yield: 67%. Anal. Calcd. For
C30H44N2O3S(%): C, 70.3; H, 8.6; N, 5.5; Found: C, 70.0; H, 8.9; N,
5.3.
1H NMR (300 MHz, CDCl3, ppm): d 12.48 (s, 1H); 9.03 (s, 1H);
(b) K. Ohta, H. Muroki, K. Hatada, A. Takagi, H. Ema, I. Yamamoto, K. Matsuzaki,
Mol. Cryst. Liq. Cryst. 140 (1986) 163;
(c) K. Ohta, H. Ema, H. Muroki, I. Yamamoto, K. Matsuzaki, Mol. Cryst. Liq.
Cryst. 147 (1987) 61.
3
7.84 (d, AA0XX0 system, 2H, JHH = 8.8 Hz); 7.55 (d, AA0XX0 system,
3
3
2H, JHH = 9.1 Hz); 6.99 (d, AA0XX0 system, 2H, JHH = 8.8 Hz); 6.92
3
(d, AA0XX0 system, 2H, JHH = 9.1 Hz); 3.99–3.91 (m, 3H), 1.85–
1.76 (m, 2H); 1.60–1.24 (m, 20H); 0.96 (m, 9H).