Spectroscopic studies of some thiosemicarbazide compounds derived from Girard's T and P

Article abstract of DOI:10.1016/j.saa.2006.02.063

Three new derivatives of thiosemicarbazides, derived from the reactions of ethyl-, allyl- and phenyl isothiocyanates with Girard's T [(carboxymethyl) trimethylammonium chloride hydrazide] and P [1-(carboxymethyl) pyridinium chloride hydrazide], have been

Full text of DOI:10.1016/j.saa.2006.02.063

Spectrochimica Acta Part A 66 (2007) 480–486
Spectroscopic studies of some thiosemicarbazide
compounds derived from Girard’s T and P
M.M. Mostafa
Chemistry Department, Faculty of Applied Sciences, Umm Al-Qura University, P.O.Box 6503-25, Makkah, Saudi Arabia
Received 26 September 2005; accepted 27 February 2006
Abstract
Three new derivatives of thiosemicarbazides, derived from the reactions of ethyl-, allyl- and phenyl isothiocyanates with Girard’s T [(car-
boxymethyl) trimethylammonium chloride hydrazide] and P [1-(carboxymethyl) pyridinium chloride hydrazide], have been isolated and charac-
1
terized by chemical analyses, conductivities, spectral (IR, H NMR) and molecular weight measurements. The most important assignments of
the functional groups in the isolated solid organic compounds have been determined using IR spectra. Also, the main functional groups in the
1
skeleton of these compounds have been characterized using H NMR spectra. Moreover, a comparative studies between the three thiosemicarbazide
+
+
3 3 5 5
derivatives have been carried out. The role of the existence of ethyl-, allyl-, phenyl-, [(CH ) N –] and [C H N –] on the position of the functional
groups has been investigated. Finally, the absence of any type of hydrogen bonding (inter- and/or intra-) within these compounds is discussed on
1
the basis of the data of melting points, IR and H NMR spectra and molecular weight measurements.
©
2006 Elsevier B.V. All rights reserved.
Keywords: Spectroscopic studies; Thiosemicarbazide derivatives; Girard’s T and P derivatives
1
. Introduction
synthesize some new complex compounds and characterizing
their chemical and geometries structures.
No studies have been carried out on the derivatives of
the thiosemicarbazide compounds derived from Girard’s T
and P, except these done by us [1–4]. Also, in continuation
of our earlier work [5–15] on thiosemicarbazide derivatives
and its metal complexes, we extend this study to involve
N-{[(allylamino) thioxomethyl] hydrazinocarbonylmethyl}
trimethyl ammonium chloride (ATHTC), N-{(ethylamino)
thioxomethyl] hydrazine carbonylmethyl}trimethyl ammonium
chloride (ETHTC) and N-{[phenylamino) thioxomethyl]
hydrazinocarbonylmethyl}pyridinium chloride (PTHPC).
Another reason for continuing this work is to study the role
2. Experimental
Three thiosemicarbazide derivatives, derived from the
reactions of Girard’s T with allyl- and ethyl isothiocyanates
and Girard’s P with phenyl isothiocyanate, were synthesized.
The isolated compounds are namely, N-{[(allylamino) thiox-
omethyl]hydrazinocarbonylmethyl} trimethyl ammonium
chloride (ATHTC), N-{(ethylamino) thioxomethyl] hydrazine
carbonyl methyl}trimethyl ammonium chloride (ETHTC)
and N-{[phenylamino) thioxomethyl] hydrazinocarbonyl-
methyl}pyridinium chloride (PTHPC) and are represented in
Structure 1.
4
of ethyl-, allyl- and phenyl- groups attached to the NH group
1
(
Structure 1) on the positions of the IR bands and H NMR
signals. In addition, the effect of the methyl and/or the pyridyl
groups attached to the CH2 group on the behavior of these
compounds has been reported. Finally, the importance of the
compounds containing thiosemicarbazide moiety in medicinal
uses [16] gives us the push to stimulate this work. Some of these
compounds have been reported earlier by us [3,7] as ligands to
The first two compounds (ETHTC, ATHTC) were synthe-
sized by boiling under reflux a solution of G.T (16.8 g, 0.1 M)
withethylisothiocyanate(8.8 ml, 0.1 M)andallylisothiocyanate
(9.8 ml, 0.1 M) in absolute ethanol for 2 h. The third compound
of this series (PTHTC) was prepared by boiling under reflux
equivalent amounts of G.P (18.8 g, 0.1 M) with phenyl isothio-
cyanate (12 ml, 0.1 M) in absolute ethanol (100 ml) for 4 h. The
white products were filtered off hot and washed thoroughly with
cold solution of absolute ethanol and dry diethyl ether, respec-
E-mail address: mmostafa84@yahoo.com.
1
386-1425/$ – see front matter © 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2006.02.063

M.M. Mostafa / Spectrochimica Acta Part A 66 (2007) 480–486
481
Structure 1.
◦
tively. The isolated products were dried in an oven at 90 C,
crystallized from absolute EtOH and finally dried in a vacuum
desiccator over silica gel. The purity of the isolated compounds
were checked by m.p., TLC and molecular weight measure-
ments.
Structure 2.
3
. Results and discussion
−
1
1
Partial IR (cm )(KBr) for ATHTC (A2): υ(NH ) 3210,
4
2
υ(NH ) 3164, υ(NH ) 3100, υ(CO) 1700, υ(CS) 1222, 730,
The analytical data of the three compounds under investiga-
1
1
υ(N–N) 964; H NMR(400 MHz, d -DMSO): δ 10.87 (NH ), δ
6
tion are listed in Table 1. All the compounds are quite stable
in air and light, insoluble in most common non-polar solvents
but soluble in polar solvents. Consequently, the molar conduc-
tivities of the three compounds were carried out in DMSO and
their values fall in the range 32–38 ꢀ cm mol (Table 1).
The values suggest that the compounds are electrolytic in nature
17] as well as the existence of one ionizable chloride ion out-
side the brackets (Structure 2). Also, the results show that the
isolated compounds have low melting points (194–210 C) sug-
gesting straightforwardly the absence of any type of hydrogen
bonding within these molecules and the obscure of any type of
polymeric structure. Moreover, the molecular weight determi-
nations for all the three compounds coincide with the proposed
formulae of the thiosemicarbazide derivatives (Table 1).
The most important IR assignments of the isolated solid
thiosemicarbazide derivatives have been determined by com-
paring the IR spectra of the compounds under investigation with
our previous work involving of G.P [18] and G.T [19,20] as well
as the work done by Masui and Ohmori [21] and by us [1–4].
The IR spectrum of ATHTC in KBr shows two bands at 1700
4
2
9
.95 (NH ), δ 8.54 (NH ), δ 5.05 (NH·CH2), δ 5.8 CH CH2), δ
.27 (CH CH2), δ 3.43 (N·CH2), δ 3.26 {(CH3)}.
4
−
1
1
Partial IR (cm )(KBr) for ETHTC (A1): υ(NH ) 3320,
2
4
υ(NH ) 3139, υ(NH ) 3090, υ(CO) 1704, υ(CS) 1290, 740,
−1
2
−1
1
1
υ(N–N) 960; H NMR(400 MHz), d -DMSO) δ 10.76 (NH ), δ
.35 (NH ), δ 8.41 (NH ), δ CH3 (Et) 1.06, δ CH2(Et) 3.44, δ
6
4
2
9
[
(
CH3)3 3.25, δ CH2 (CH2·CO) 4.28.
−
1
1
Partial IR (cm ) (KBr) for PTHPC (A3): υ(NH ) 3286,
◦
4
2
υ(NH ) 3210, υ(NH ) 3021, υ(CO) 1700, υ(CS) 1197, 746,
υ(N–N) 950; H NMR(400 MHz, d -DMSO): δ 11.13 (NH ), δ
1
1
1
6
2
4
0.09 (NH ), δ 9.88 (NH ), δ 5.75 CH2 (N·CH2), δ 7.17–9.17
(
Py + Ph).
2
.1. Physical measurements
IR spectra were recorded in KBr and/or Nujol mull with
a Mattson 5000 FTIR Spectrometer at Mansoura University,
1
Egypt. H NMR spectra in d -DMSO were carried out on a
6
1
Joel H NMR Spectrometer (400 MHz) at King Saud University,
Riyadh, KSA. Molar conductance measurements were obtained
−1
and 1222 cm assigned to υ(CO) and υ(CS) vibrations, respec-
tively. The absence of any bands above 3480 cm as well as
in the 2600–2550 cm range assignable to υ(OH) and υ(SH)
−
3
with YSI model 35 conductivity bridge using 10 M solution
−1
◦
in DMSO at 25 C. The analyses of C, H, N and S (Table 1) were
−1
performed at King Fahd for Medical Research Center, Jeddah
at the Microanalytical Unit using Perkin-Elmer Microanalyzer
model 2400. Molecular weight measurements were carried out
by Rast’s method using camphor as a solvent.
vibrations, respectively, suggests that the CO and CS groups
remain as shown in Structure 3. Also, the absence of any bands
in the 2300–2500 and 1900–2100 cm regions suggests the
−1
obscure of any type of hydrogen bonding (inter-, or intra-)
Table 1
Analytical and some physical properties of the thiosemicarbazide derivatives
◦
a
Compound
Yield (%)
M.P. ( C)
Found (calculated, %)
ꢁm in DMSO
C
H
N
S
M.Wt
A1 = ETHTC = C9H19N4OSCl
A2 = ATHTC = C8H19N4OSCl
A3 = PTHTC = C14H15N4OSCl
94
90
97
210
196
194
37.5 (37.7)
40.3 (40.5)
52.1 (52.1)
7.4 (7.5(
7.1 (7.2)
4.8 (4.7)
21.9 (22.0)
20.7 (21.0)
17.6 (17.4)
12.5 (12.6)
11.7 (12.0)
11.7 (17.4)
253 (255)
260 (267)
309 (323)
38
35
32
a
−1
2
−1
ꢀ
cm mol .

4
82
M.M. Mostafa / Spectrochimica Acta Part A 66 (2007) 480–486
Structure 3.
Structure 4.
−
1
within these compounds. The three bands observed at 1544,
groups [23]. Also, the two bands at 1197 and 746 cm are
−
1
−
1
1
471 and 1415 cm are more likely attributed to υ(–N–C S)
attributed to υ(CS) vibration. The strong band at 1700 cm is
assignedtothecarbonyloxygengroup. Theabsenceofanybands
in the 1900–2200 and 2300–2500 cm regions suggests the
absence of any types of hydrogen bonding. Also, the obscure of
any band in the 2600–2550 cm region due to υ(SH) vibration
indicates that the ligand exists mainly in the thioketo form.
The H NMR spectrum of PTHPC in d -DMSO (Fig. 3)
shows three singlet signals at 11.13, 10.09 and 9.88 ppm, down-
[
22] vibrations. Moreover, the three strong bands at 3210, 3164
−
1
1
2
4
−
1
and 3100 cm are assigned to υ(NH ), υ(NH ) and υ(NH )
vibrations, respectively. Finally, the band observed at 916 cm
−
1
−
1
is assigned to υ(N–N) vibration [23].
1
The H NMR spectrum of ATHTC in d -DMSO (Fig. 1)
6
1
shows two singlet signals at 10.87 and 9.43 ppm, downfield of
6
1
4
TMS, assigned to the protons of (NH ) and (NH ), respectively.
2
1
The signal assigned to the proton of NH appears as a triplet sig-
field with respect to TMS, assignable to the protons of NH ,
4
2
nal centered at 8.54 ppm. The two signals at 3.26 and 3.43 ppm
with ratio 3:2 are assigned to the protons of CH3 and CH2
NH and NH , respectively. The singlet signal at 5.75 ppm is
attributed to the protons of CH2 (N–CH2) group. The multiple
signals in the 7.17–9.17 ppm region are attributed to the pro-
tons of the pyridyl and phenyl groups. The latter signals are
commensurate with ten protons attributable to five protons for
both phenyl and pyridyl groups. The value of molar conductance
10 M) of PTHPC in DMSO (32.0 ꢀ cm mol ) suggests
the electrolytic nature and the existence of one ionizable chloride
ion outside the bracket as shown in Structure 5.
(
N·CH2), respectively. Moreover, the quartet signal at 5.05 and
the doublet signal at 4.27 ppm are assigned to the protons of the
CH2 (–NH–CH2) and CH2 (–CH CH2), respectively. Finally,
the sextet signal centered at 5.8 ppm is assigned to the protons of
−
3
− −1 −1
3
2
the allyl CH group. The value of molar conductance (10 M)
(
−
1
2
−1
of ATHTC in DMSO (35.0 ꢀ cm mol ) suggests the elec-
trolytic nature [17] and the existence of one ionizable chloride
ion outside the bracket as shown in Structure 3.
On comparing the effect of R [(CH3)3, C H N] on the posi-
tions of the carbonyl band in the IR spectra, we found that these
groups have no effects on the absorption of the carbonyl band.
5
5
The IR spectrum of ETHTC in KBr shows three bands at
−
1
1
2
4
3
320, 3139 and 3090 cm assigned to υNH , υNH and υNH
−1
vibrations, respectively. Also, the bands at 1550, 1484 and
The carbonyl band is observed at 1700, 1704 and 1700 cm
−
1
1
450 cm are assigned to υ(–N–C S) vibrations [22]. The car-
for ATHTC, ETHTC and PTHPC, respectively. The existence
of this band within the same wavenumber is attributed mainly
to the effect of separation of the carbonyl oxygen group from R
by CH2 group and consequently the R groups have no effects on
the position of the carbonyl oxygen (CO). Contrarily, we found
−
1
bonyl oxygen band is observed at 1704 cm . The absence of
any bands due to OH and SH suggests that ETHTC is mainly
existed in the keto form as well as the absence of any type of
hydrogen bonding (inter- and intra-).
1
1
The H NMR spectrum of ETHTC in d -DMSO (Fig. 2)
6
that the position of the CH signal in the H NMR spectra is
2
shows three singlet signals with equal intensity at 10.76, 9.35
and 7.51 ppm, downfield with respect to TMS, assigned to the
dramatically affected by the presence of the R group [(CH3)3–,
C H N–]. The CH2 signal is observed at 3.43, 3.44 and 5.75 ppm
5
5
1
4
2
1
protons of NH , NH and NH , respectively. A triplet signal
centered at 1.06 ppm is attributed to the protons of the CH3
group (–CH2–CH3), while the protons of the CH2 (–CH2–CH3)
is observed as quintet signal centered at 3.44 ppm. On the other
hand, the trimethyl group [(CH3)3] exists as a singlet signal at
in the H NMR spectra of ATHTC, ETHTC and PTHPC, respec-
tively. The position of this signal is quite similar in case of
ATHTC and ETHTC but differs in case of PTHPC. This indi-
cates that the position of CH2 signal in the first two compounds
are quite similar due to the existence of the same group {(CH3)3}
which is directly attached to the (CH2) group, while the upfield
3
.25 ppm. Finally, the protons of CH2 group (–CH2–CO) are
observed as a singlet at 4.28 ppm. The value of molar con-
shift of the CH2 signal in case of PTHPC is attributed to the
−
3
1
2
1
+
ductance (10 M) of ETHTC in DMSO (38.0 ꢀ cm mol )
suggests the electrolytic nature and the existence of one ioniz-
able chloride ion outside the bracket [17] as shown in Structure
effect of the neighboring pyridine group (C H N) to the CH2
5
5
group. This can be explained on the basis of the high deshield-
+
ing effect of the (C H N) group in comparison to that of the
5
5
+
4
.
trimethyl ammonium group [(CH3)3N ]. Also, the presence of
asymmetric nitrogen atom of the pyridine group neighboring
Finally, the three sharp bands observed at 3286, 3210 and
−
1
1
3
021 cm in the IR spectrum of PTHPC are assigned to υ(NH ),
2
4
υ(NH ) and υ(NH ) vibrations, respectively. The four bands
observed at 1635, 1595, 1533 and 1492 cm are assigned to
−
1
υ(C N) and υ(C C) vibrations of both the pyridyl and phenyl
Structure 5.

M.M. Mostafa / Spectrochimica Acta Part A 66 (2007) 480–486
483
Fig. 1. 1H NMR spectrum of PTHTC in d6-DMSO.

4
84
M.M. Mostafa / Spectrochimica Acta Part A 66 (2007) 480–486
Fig. 2. 1H NMR spectrum of ETHTC in d6-DMSO.

M.M. Mostafa / Spectrochimica Acta Part A 66 (2007) 480–486
485
Fig. 3. 1H NMR spectrum of PTHTC in d6-DMSO.

4
86
M.M. Mostafa / Spectrochimica Acta Part A 66 (2007) 480–486
to the CH2 group makes the two protons of this group are not
equivalent.
the allyl and ethyl groups are quite similar, meanwhile the exis-
tence of the phenyl group neighboring to the NH signal causes
a downfield shift due to the mesomeric and inductive effects.
4
4
On the other hand, the NH band is observed at 3100,
−
1
3
090 and 3021 cm in the IR spectra of ATHTC, ETHTC and
PTHPC, respectively. This suggests that the effect of both the
References
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4
[
1] M.M. Mostafa, M.H. Abdel-Rhman, Spectrochim. Acta 56A (2000) 2341.
[
24] toward the NH group and hence their absorption band is
−
1
[2] M.M. Mostafa, R.M. El-Shazly, T.H. Rakha, M.H. Abdel-Rhman, Trans.
Met. Chem. 27 (3) (2002) 337.
[
[
quite similar (3100, 3090 cm ). Contrarily, the existence of the
neighboring phenyl group (C H –) to the NH group shifts the
4
6
5
3] A.A. El-Asmy, M.M. Mostafa, J. Coord. Chem. 12 (1983) 291.
4] A.A. El-Asmy, M.M. Mostafa, Polyhedron 2 (1983) 591.
4
−1
NH band to a remarkable lower wavenumber (3021 cm ) in
comparison to these observed in case of ATHTC and ETHTC.
This is explained on the basis of the mesomeric effect [25] of
the phenyl group which causes the lengthening or weakening
of the bond length and consequently leading in lowering of the
[5] M.M. Mostafa, A.M. Shallaby, A.A. El-Asmy, J. Inorg. Nucl. Chem. 43
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[8] M.M. Mostafa, A.A. El-Asmy, J. Coord. Chem. 12 (1983) 197.
(
[
[
3
1
absorption frequency of this group. Also, the H NMR spec-
(
tra of ATHTC, ETHTC and PTHPC show the proton signal of
2
[
9] M.M. Mostafa, A.A. El-Asmy, G.M. Ibrahim, Trans. Met. Chem. 8 (1983)
8.
the NH signal at 9.43, 9.44 and 9.75 ppm, respectively. The
2
observation of the signal due to the proton of the NH group,
[
[
[
[
[
[
10] A.A. El-Asmy, K.M. Ibrahim, M.M. Bekheit, M.M. Mostafa, Synth. React.
Inorg. Met. Org. Chem. 14 (1984) 785.
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Acad. Sci. (Hung) 119 (1985) 355.
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Inorg. Met. Org. Chem. 15 (1985) 1247.
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Mansoura 4 (1977) 193.
for the first two compounds at the same position, suggests that
the effect of both the allyl- and ethyl- groups on the proton of
4
NH is approximately similar and hence the signal for both com-
pounds (ATHTC and ETHTC) are quite identical. This behavior
is quite similar and coincides to a great extent with the results
obtained from the IR spectra. The same behavior is observed in
the position of the thioketo group (CS) for ATHTC, ETHTC and
PTHPC.
In conclusion, no effects have been observed for the [(CH3)3–
and C H N–] groups on the position of the carbonyl band for
5
5
[
[
[
the three compounds (ATHTC, ETHTC and PTHTC). This is
explained on the basis of the separation of the carbonyl band
1
from R by the CH2 group. In contrarily, the CH2 signal in H
[
[
[
19] M.N.H. Moussa, F.I.M. Taha, M.M. Mostafa, Egypt J. Chem. 162 (1973)
NMR spectra is dramatically affected by the presence of R group
especially in case of PTHPC due to the high shielding effect the
pyridine group as well as the existence of asymmetric nitrogen
atom beside the two protons of CH2 group. On the other hand,
1
15.
20] F.I. Taha, M.N.H. Moussa, A.M. Shallaby, M.M. Mostafa, Acta Chim. Sci.
Hung) 90 (1976) 339.
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[22] C.N. Rao, R. Venkatarghavan, Spectrochim. Acta 18 (1962) 541.
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(1968) 430.
24] M. Hesse, H. Meier, B. Zeeh, Spectroskopische Methoden in der Organis-
chan Chemie, Georg Thieme Verlag, Stuttgart, New York, 1978.
25] R.M. Silverstein, G. Bassler, T.C. Morril, Spectrometric Identification of
Organic Compounds, 6th ed., John Wiley, 1991.
(
4
the position of the NH band in the IR spectra of ATHTC and
[
[
[
ETHTC are quite similar due to their similarity in their elec-
4
tronic effect. The neighboring of the phenyl group to the NH
group causes a shift of this band to lower wavenumber due to
4
the mesomeric effect. Finally, the protons of the NH signal in
case of ATHTC and ETHTC are similar since the effect of both