Thiosemicarbazones as effective fluorescent sensors for cations and anions

Article abstract of DOI:10.1134/S1070363212090137

Abstract- Series of anthracene-containing chemosensors was synthesized by the reaction of 4-Rthiosemicarbazides with aromatic aldehydes. Spectral studies showed their high sensory activity with respect to a group of cations and anions like Hg²⁺, F^-, CN^-, AcO^- etc. Pleiades Publishing, Ltd., 2012.

Full text of DOI:10.1134/S1070363212090137

ISSN 1070-3632, Russian Journal of General Chemistry, 2012, Vol. 82, No. 9, pp. 1533–1536. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © I.E. Tolpygin, 2012, published in Zhurnal Obshchei Khimii, 2012, Vol. 82, No. 9, pp. 1497–1500.
Thiosemicarbazones as Effective Fluorescent Sensors
for Cations and Anions
I. E. Tolpygin
Research Institute of Physical and Organic Chemistry, Southern Federal University,
pr. Stachki 194 /2, Rostov-on-Don, 344090 Russia
e-mail: tolpygin@ipoc.sfedu.ru
Received July 21, 2011
Abstract— Series of anthracene-containing chemosensors was synthesized by the reaction of 4-R-
thiosemicarbazides with aromatic aldehydes. Spectral studies showed their high sensory activity with respect to
a group of cations and anions like Hg2+, F–, CN–, AcO– etc.
DOI: 10.1134/S1070363212090137
Recently a significant progress was reached in the
development of fluorescent chemosensors capable to
recognize selectively different analytes of ionic nature,
which is primarily associated with the development of
research of the sensory processes [1–4]. The basis of
the most effects observed in the ionochromic mole-
cules consists in two principal types of interactions:
electrostatic and hydrogen bonds formation [1, 2].
thioamide tautomeric fragments capable of forming
stable hydrogen bonds [8–10]. Several derivatives of
thiosemicarbazide exhibit sensory properties with
respect to both cations and anions. In these compounds
the receptor often acts also as a signal fragment [11–
14]. The presence of a fluorescent substituent in the
sensor molecule increases its sensitivity and creates
advantages in accuracy and mobility at performing
analyses.
Thus, the effect of anion sensors is based on their
ability to form hydrogen bonds between their receptor
part and a negatively charged pollutant. Depending on
the structure of the receptor, such sensors are able to
selectively recognize anions of different nature,
geometry, and the charge [5–7]. Most effective in this
case are sensors of neutral nature containing amide or
We have previously developed mono- and dithio-
urea derivatives containing 9-anthrylmethyl fragment
as highly effective sensors to Hg2+ cations [15, 16]. To
obtain new sensitive sulfur-containing cation and anion
sensors, we synthesized a number of thiosemicar-
bazides I–VI.
H
N
H
N
H
R
N
c
S
H
N
H
N
а or b
H
R
RNH2
N
H
VII−XI
d
S
H
N
H
N
H
I−VI
R
N
S
HO
XII
а, (1) CS2, NH4OH, (2) ClCH2CO2Na, (3) NH2NH2; b, NH2NHC(S)SMe; c, 9-acarbaldehyde, H+, 1-BuOH; d, 2-
hydroxynaphthalene-1-carbaldehyde, H+; R = Н (I, VII), CH2Ph (II, VIII), CH2CH2Ph (III, IX), 9-C14H9CH2 (IV, XII), 2-
MeOC6H4 (V, X), 4-Et2NC6H4 (VI, XI).
1533

1534
TOLPYGIN
IV VII VIII IX
X XI XII
I/I0
The relative change in fluorescence intensity of compounds IV, VII–XII (c = 5.0×10–6 M) in MeCN with additives of NBu4+ A–
salts (c = 2.5 × 10–5 M).
Thioamides II and III were synthesized by
successive interaction of the corresponding amines
with carbon disulfide, sodium chloroacetate, and hyd-
razine hydrate (method a) [17], and derivatives IV–VI,
by the reaction of aromatic amines and (anthracen-9-
ylmethyl)amine with methylhydrazine carbodithioate
spectrum contains one broad band. On the basis of
fluorescence spectra we studied the chemosensory
activity of the obtained thioamides I–XII with respect
to the group of cathions: H+, Zn2+, Cd2+, Cu2+, Co2+,
Ni2+, Pb2+, and Hg2+. As was the case of the previously
described derivative I [11], the most selective is the
response to the ions Cu2+ and Hg2+. This is primarily
due to the presence of soft nucleophilic center, the
sulfur atom, and the possibility of prototropic
tautomerism in the thioamide fragment. The maximum
sensitivity with respect to the mercury(II) ions in a
series of derivatives is exhibited by thiosemicarbazone
VI: at the interaction 16-fold increase in the fluore-
scence burn occurs. Other cations did not cause any
significant changes in the fluorescence intensity (I/I0 in
the range of 0.7–2.3). At adding trifluoroacetic acid to
a soluthion of sensor IV a red shift of fluorescence
maximum by 40 nm occurs with a slight increase in its
intensity.
1
(method b) [18]. The H NMR spectrum of compound
IV contains characteristic signals of protons of the
thiosemicarbazide group (both NH2 and NH), and of
the CH2 fragment (a doublet, δ 5.63 ppm, J 7.2 Hz).
The thiosemicarbazides obtained were then brought
into the condensathion reacthion with anthracene-9-
carbaldehyde to form compounds VII–XI and 2-
hydroxynaphthalene-1-carbaldehyde to obtain the deri-
vative XII. The formation of thiosemicarbazone
1
fragment is indicated by the disappearance in the H
NMR spectra of the signal of NH2 protons and down-
field shift of the signals of two NH protons.
According to the data of electron absorption
spectroscopy, compounds IV and XII possess only the
fluorescence of the “classic” anthracene type with
λmax = 412–414 nm. In the case of derivatives VII–XI
the maximum suffers a red shift by ~15–85 nm relative
to the ordinary values, and the structure of the
spectrum is unusual for the anthracene derivatives: the
We investigated also the interaction of the
derivatives IV, VII–XII with tetrabutylammonium
salts containing anions F– , Cl–, CN–, SCN–, NO3–,
H2PO2–, ClO4–, HSO4–, and AcO– (see the figure).
Significant changes in the fluorescence intensity
were noted only at the interaction with fluoride,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 82 No. 9 2012

THIOSEMICARBAZONES AS EFFECTIVE FLUORESCENT SENSORS
1535
cyanide, and acetate anions. The maximum fluore-
scence burn occurred at adding these anions to the
derivatives X/XI, 14.0/9.0, 14.0/21.0, and 11.0/4.0
times, respectively. With the other derivatives no high
sensitivity and selectivity in the detecthion of anions
was observed.
3-Amino-1-(anthracen-9-ylmethyl)thiourea (IV).
Yield 73%, mp 254–255ºC (1-butanol). IR spectrum,
ν, cm–1: 3300, 3100, 1520, 1450. 1H NMR spectrum, δ,
ppm (DMSO-d6): 4.20 br.s (2H, NH2), 5.63 d (2H, J
7.2 Hz, CH2), 7.40–8.56 m (10H, HAr, NH); 8.69 br.s
(1H, NH). The fluorescence spectrum in acetonitrile,
λ
max, nm (c = 5×10–5 M): 415. Found, %: C 68.38, H
In going from thiosemicarbazide X to XI a sharp
increase occurs in the selectivity with respect to the
cyanide anion. In addithion, the ions CN– and F– cause
blue shift of the fluorescence maximum of thioamides
X by ~25 nm. The most significant shift of
fluorescence maxima occurs at adding NBu4+F– to a
soluthion of imine VIII: a blue shift by 84 nm, and at
5.30; N 14.84; S 11.48. Calculated, %: C 68.30; H
5.37; N 14.93; S 11.40.
3-Amino-1-(2-methoxyphenyl)thiourea (V). Yield
80%, mp 166–167ºC (EtOH). Found, %: C 48.80; H
5.54; N 21.22; S 16.33. Calculated, %: C 48.71; H
5.62; N 21.30; S 16.25.
+
adding NBu4 CN– to a soluthion of imine XII: a red
3-Amino-1-[4-(diethylamino)phenyl]thiourea (VI).
Yield 87%, mp 137–138ºC (MeCN). Found, %: C
55.50; H 7.55; N 23.43; S 13.52. C11H18N4S. Cal-
culated, %: C 55.43; H 7.61; N 23.51; S 13.45.
shift by 49 nm.
Thus, the study of 3-[(anthracen-9-ylmethylidene)-
amino]-1-R-thioureas as potential chemosensors for
various cations and anions showed their high selec-
tivity towards Hg2+ cations and F– and CN– anions.
General procedure for obtaining compounds
(VII–XII, XIII). A soluthion of 2 mmol of an appro-
priate aminothiourea I–VI and 2 mmol of anthracene-
9-carbaldehyde (synthesis of compounds VII–XII) or
2-hydroxynaphtalene-1-carbaldehyde (synthesis of
imine XIII) in 20 ml of 1-butanol was heated for 2 h.
The solvent was evaporated in a vacuum and the
residue was crystallized.
EXPERIMENTAL
1
The H NMR spectra were obtained on a Varian
Unity-300 spectrometer (300 MHz). As internal
references residual signals of CHCl3, δ 7.25 ppm, and
(CH3)2SO, δ 2.50 ppm, were used. The electron
absorption spectra were recorded on a Varian Cary 100
spectrophotometer, the luminescence spectra were
measured on a Hitachi 650-60 and a Varian Eclipse
spectrofluorimeters. The IR spectra were recorded on a
Specord 75IR instrument from the samples in mineral
oil. Melting points were determined in glass capillaries
on a PMP (M) device. Completeness of the reactions
and individuality of the compounds obtained were
monitored by TLC (plates Silufol U254, eluent
chloroform, development by the iodine vapor in a
humid chamber).
3-[(Anthracen-9-ylmethylidene)amino]thiourea
(VII). Yield 85%, mp 225–226ºC (193–194ºC [11]).
IR spectrum, ν, cm–1: 3300, 3100, 1595, 1530, 1460,
1
1235. H NMR spectrum (DMSO-d6), δ, ppm: 7.35
br.s (1H, NH); 7.42–7.60 m (4H, HAr, NH2), 5.8 d (4H,
J 8.6 Hz , HAr); 8.12 br.s (1H, NH); 8.50–8.58 m (3H,
HAr); 9.28 s (1H, CH) 11.65 s (1H, NH). The
fluorescence spectrum in acetonitrile, λmax, nm (c =
5×10–5 M): 497. Found, %: C 68.85; H 4.75; N 14.96;
S 11.44. C16H13N3S. Calculated, %: C 68.79; H 4.69; N
15.04; S 11.48.
General procedure for the preparathion of 1-R-
3-aminothioureas (II–VI). Derivatives II and III
were synthesized by the method of [17], IV–VI,
according to [18].
3-[(Anthracen-9-ylmethylidene)amino]-1-benzyl-
thiourea (VIII). Yield 88%, mp 232–233ºC. IR
1
spectrum, ν, cm–1: 3290, 3100, 1600, 1535, 1460. H
NMR spectrum (DMSO-d6), δ, ppm: 4.86 d (2H, J
7.0 Hz, CH2), 7.12–7.60 m (9H, HAr); 8.04 d (4H, J
8.6 Hz, HAr); 8.42–8.60 m (4H, HAr, NH); 9.30 s (1H,
CH), 11.80 s (1H, NH). The fluorescence spectrum in
acetonitrile, λmax, nm (c = 5×10–5 M): 497. Found, %:
C 74.85; H 5.25; N 11.29; S 8.61. C23H19N3S. Cal-
culated, %: C 74.77; H 5.18; N 11.37; S 8.68.
3-Amino-1-benzylthiourea (II). Yield 82%, mp
132–133ºC (MeCN). Found, %: C 52.95; H 6.05; N
23.23; S 17.77. C8H11N3S. Calculated, %: C 53.01; H
6.12; N 23.18; S 17.69.
3-Amino-1-[2-phenylethyl]thiourea (III). Yield
82%, mp 118–119ºC (MeCN). Found, %: C 55.41; H
6.65; N 21.44; S 16.50. Calculated, %: C 55.35; H
6.71; N 21.52; S 16.42.
3-[(Anthracen-9-ylmethylidene)amino]-1-(2-
phenylethyl)thiourea (IX). Yield 81%, mp 165–
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 82 No. 9 2012

1536
TOLPYGIN
166ºC. IR spectrum, ν, cm–1: 3300, 3100, 1590, 1530,
1455. H NMR spectrum (DMSO-d6), δ, ppm: 3.00 m
REFERENCES
1
1. Demchenko, A.P., Introducthion to Fluorescence
Sensing, Springer, 2008.
2. Optical Sensors and Switches (Molecular and Supra-
molecular Photochemistry), Ramamurthy, V. and
Schanze, K.S., Eds., New York: Marcel Dekker, vol. 7,
2001.
(2H, J 7.4 Hz, CH2) 4.00 to (2H, J 7.2 Hz, CH2), 7.08–
7.33 m (5H , HAr); 7.43–7.68 m (5H, HAr, NH); 7.96–
8.12 m (2H, HAr); 8.30–8.42 m (2H, HAr); 8.52 s (1H,
HAr); 9.00 s (1H, CH), 10.07 s (1H, NH). The fluore-
scence spectrum in acetonitrile, λmax, nm (c = 5×10–5 M):
455. Found, %: C 75.21; H 5.45; N 11.04; S 8.30.
C24H21N3S. Calculated, %: C 75.16; H 5.52; N 10.96;
S 8.36.
3. Anslyn, E.V. and Wang, B., Chemosensors: Principles,
Strategies, and Applicathions, Wiley Series in Drug
Discovery and Development Series, Chihester, Wiley &
Sons, 2011.
3-[(Anthracen-9-ylmethylidene)amino]-1-(2-
methoxyphenyl)thiourea (X). Yield 78%, mp 212–
212–213ºC. IR spectrum, ν, cm–1: 3280, 3080, 1520,
4. Stone, D.C., Chemical and Biological Sensors,
1
1465. H NMR spectrum (DMSO-d6), δ, ppm: 3.78 s
Cambridge: RSC, 2011.
(3H, CH ), 6.90–7.20 m (3H, HAr); 7.50–7.75 m (4H,
3
5. Martinez-Manez, R. and Sancenon, F., Chem. Rev.,
HAr); 8.18 d (2H, J 8.4 Hz, HAr); 8.57–8.82 m (4H ,
HAr); 9.48 a (1H, CH), 9.96 s (1H, NH), 12.16 s (1H,
2003, vol. 103, no. 11, p. 4419.
6. Garcia-Espana, E.D., Pilar, Llinares, J.M., and Bianchi, A.,
NH). The fluorescence spectrum in acetonitrile, λmax
,
nm (c = 5 × 10–5 M): 475. Found, %: C 71.71; H 5.05;
N 10.85; S 8.24. C23H19N3OS. Calculated, %: C 71.66;
H 4.97; N 10.90; S 8.32.
Coord. Chem. Rev., 2006, vol. 250, nos. 23–24, p. 2952.
7. Gunnlaugsson, T., Glynn, M., Tocci, G.M., Kru-
ger, P.E., and Pfeffer, F.M., Coord. Chem. Rev., 2006,
vol. 250, nos. 23–24, p. 3094.
3-[(Anthracen-9-ylmethylidene)amino]-1-[2-(di-
ethylamino)phenyl]thiourea (XI). Yield 92%, mp
186–187ºC. IR spectrum, ν, cm–1: 3300, 3080, 1510,
8. Chen, W., Zuckerman, N.B., Konopelski, J.P., and
Chen, S., J. Phys. Chem., A, 2009, vol. 113, no. 34,
p. 9474.
1
1460. H NMR spectrum (DMSO-d6), δ, ppm: 1.15 t
9. Ghosh, K. and Sen, T., Tetrahedron Lett., 2008, vol. 49,
(6H, J 7.2 Hz, 2CH ) 3.32 to (4H, J 7.0 Hz, 2CH2),
3
no. 50, p.7204.
6.65 d (2H, J 8.2 Hz, HAr); 7.38 d (2H, J 8.2 Hz, HAr);
7.42–7.70 m (4H, HAr); 8.07 d (2H, J 8.6 Hz, HAr);
8.40–8.60 m (3H , HAr); 9.06 s (2H, CH); 9.08 s (2H,
NH); 10.06 from (1H, NH). The fluorescence spectrum
in acetonitrile, λmax, nm (c = 5 × 10–5 M): 432. Found,
%: C 73.30; H 6.08; N 13.04; S 7.58. C26H26N4S.
Calculated, %: C 73.21; H 6.14; N 13.13; S 7.52.
10. Thiagarajan, V. and Ramamurthy, P., Spectrochimica
Acta, A, 2007, vol. 67, nos. 3–4, p. 772.
11. Qin, P., Niu, C., Zeng, G., Zhu, J., and Yue, L., Anal.
Sci., 2008, vol. 24, no. 9, p. 1205.
12. Zou, Q., Jin, J., Xu, B., Ding, L., and Tian, H.,
Tetrahedron, 2011, vol. 67, no. 5, p. 915.
3-[(2-Hydroxynaphthalen-1-ylmethylidene)amino]-
1-(anthracen-9-ylmethyl)thiourea (XII). Yield 82%
yield, 293–294ºC (1-butanol-DMF). IR spectrum, ν,
cm–1: 3330, 3100, 1610, 1515, 1460. 1H NMR
spectrum, δ, ppm (DMSO-d6): 5.77 d (2H, J 7.4 Hz,
CH2), 6.88–7.23 m (3H, HAr), 7.42–7.73 m (6H, HAr);
8.00–8.20 m (4H, HAr, NH); 8.40–8.60 m (3H, HAr);
8.95 s (1H, CH), 10.29 br.s (1H, NH); 11.50 br.s (1H,
13. Su, H., Lin, H., Cai, Z.-S., and Lin, H., J. Incl. Phenom.
Macrocycl. Chem., 2010, vol. 67, nos. 1–2, p. 183.
14. Zhang, Y.-M., Wang, D.-D., Lin, Q., and Wei, T.-B.,
Phosphorus, Sulfur, and Silicon, 2008, vol. 183, no. 1,
p. 44.
15. Tolpygin, I.E., Dubonosov, A.D., Bren’, V.A., Min-
kin, V.I., and Rybalkin, V.P., Zh. Org. Khim., 2003,
vol. 39, no. 9, p. 1435.
OH). The fluorescence spectrum in acetonitrile, λmax
,
nm (c = 5 × 10–5 M): 415. Found, %: C 74.38, H 4.92;
N 9.73; S 7.30. C27H21N3SO. Calculated, %: C74.46; H
4.86; N 9.65; S 7.36.
16. Tolpygin, I.E., Shepelenko, E.N., Revinskii, Yu.V.,
Tsukanov, A.V., Dubonosov, A.D., Bren’, V.A., and
Minkin, V.I., Zh. Obshch. Khim., 2010, vol. 80, no. 4,
p. 603.
ACKNOWLEDGMENTS
17. Kazakov, V.Ya. and Postovskii, I.Ya., Izv.Vuzov, Khim.
i Khim. Tekhnol., 1961, no. 2, p. 238.
This work was supported by the Program of
Southern Federal University and Russian Foundathion
for Basic Research (project no. 09-03-00052).
18. McElhinney, R.S., J. Chem. Soc., C, 1966, p. 950.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 82 No. 9 2012