Synthesis, characterization, and biological activity of some organotin pyrazolecarboxylates

Article abstract of DOI:10.1081/SIM-100001934

A series of organotin pyrazolecarboxylates of the general formula R_nSnL4_-n have been synthesized and characterized by elemental analyses, IR, ¹H NMR, and mass spectroscopy. Biological activity determinations for selected compounds indicate that these compounds have antibacterial activity.

Full text of DOI:10.1081/SIM-100001934

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SYNTHESIS, CHARACTERIZATION, AND
BIOLOGICAL ACTIVITY OF SOME ORGANOTIN
PYRAZOLECARBOXYLATES
Jinshan Li a , Guofeng Zhao a , Chuanhui Xiong a & Yongqiang Ma a
a Institute of Elemento-Organic Chemistry, Nankai University , Tianjin, 300071, People's
Republic of China
Published online: 20 Aug 2006.
To cite this article: Jinshan Li , Guofeng Zhao , Chuanhui Xiong & Yongqiang Ma (2001) SYNTHESIS, CHARACTERIZATION,
AND BIOLOGICAL ACTIVITY OF SOME ORGANOTIN PYRAZOLECARBOXYLATES, Synthesis and Reactivity in Inorganic and
Metal-Organic Chemistry, 31:1, 85-93, DOI: 10.1081/SIM-100001934
To link to this article: http://dx.doi.org/10.1081/SIM-100001934
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SYNTH. REACT. INORG. MET.-ORG. CHEM., 31(1), 85–93 (2001)
SYNTHESIS, CHARACTERIZATION,
AND BIOLOGICAL ACTIVITY OF SOME
ORGANOTIN PYRAZOLECARBOXYLATES
Jinshan Li,∗ Guofeng Zhao, Chuanhui Xiong,
and Yongqiang Ma
Institute of Elemento-Organic Chemistry, Nankai
University, Tianjin 300071, People’s Republic of China
ABSTRACT
A series of organotin pyrazolecarboxylates of the general
formula Rn SnL4−n have been synthesized and characterized by el-
emental analyses, IR, 1H NMR, and mass spectroscopy. Biological
activity determinations for selected compounds indicate that these
compounds have antibacterial activity.
Key Words: Organotin; Pyrazolecarboxylate; Antibacterial acti-
vity
INTRODUCTION
Organotin carboxylates have been widely studied due to their wide range of
applications, such as biocides and as homogeneous catalysts in industry (1–5). It
is well known that pyrazole derivatives have a broad spectrum of biological activ-
ity (6). However, studies of derivatives of pyrazolecarboxylate with main group
∗Corresponding author. E-mail: llma@eyou.com
85
Copyright ꢀ 2001 by Marcel Dekker, Inc.
www.dekker.com
C

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LI ET AL.
metalsarerelativelyfew. Inordertoinvestigatetheirbiologicalactivity, wedescribe
in this paper the synthesis and characterization of a series of organotin pyrazole-
carboxylates, which contain two active centers, namely the organotin moiety and
the pyrazolecarboxylate group.
EXPERIMENTAL
Material and Methods
All operations were performed in an atmosphere of dry argon, using Schlenk
and vacuum techniques. All solvents were dried by standard methods and distilled
prior to use. Elemental analyses were determined on a Yanaco CHN Corder MT-3
elemental analyzer. IR spectra were recorded on a Bruker Equinox 55 spectrometer
in KBr discs. 1H NMR spectra were measured on a Bruker AC-200 spectrometer
in CDCl3 solution with TMS as internal standard. Mass spectra were recorded
on a HP-5988A mass spectrometer at 70 eV with the temperature of ionization
being 200◦C. Pyrazolecarboxylic acid (see Figure 1) was prepared according to
earlier references (6,7). Organotin chlorides were synthesized by standard meth-
ods (8–10). [(PhCMe2CH2)3Sn]2O was reagent grade and was obtained from the
Beijing Chemical Company.
Synthesis of the Organotin Complexes
Pyrazolecarboxylicacid(1mmol)andpotassiumhydroxide(0.056g, 1mmol)
were stirred in 20 mL of toluene for 4 h at room temperature to prepare the
potassium salts of pyrazolecarboxylic acid. The triorganotin chloride (1 mmol) or
diorganotin dichloride (0.5 mmol) was added to the suspension of the potassium
salts of pyrazolecarboxylic acid in toluene. The mixture was stirred overnight at
room temperature. Then the solvent was evaporated under vacuum, the obtained
solid was recrystallized from CH2Cl2/petroleum ether (1:3, v/v) and dried in vacuo.
Reactions of [(PhCMe2CH2)3Sn]2O (0.526 g, 0.5 mmol) with the pyrazole-
carboxylic acid, viz, HL1 and HL2, in 1:2 molar ratio have been carried out in
R2
N
R2
N
Cl
COOH
COOH
R3
N
R1
N
R1
HL1:R1 = Me; R2 = Me, Et
HL2:R1 = Me, Ph; R2 = Me; R3 = OPh
Figure 1. Structures of the ligands.

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ORGANOTIN PYRAZOLECARBOXYLATES
87
refluxing benzene (20 mL). The mixture was refluxed with constant stirring for
10 h. Then the reaction mixture was treated as above.
RESULTS AND DISCUSSION
All of the newly synthesized compounds are white solids, which are stable
in air and soluble in common organic solvents. The analytical data are in good
agreement with the proposed stoichiometry of the compounds (see Table 1).
KL1
KL2
R43SnL1
R43SnL2
1:1
−→
r.t.
R43SnCl +
+ KCl
Compd.
L
R1
R2
R3
R4
Ph
Cy
n-Bu
Ph
Ph
Ph
Cy
(1)
(2)
(3)
(4)
(5)
(6)
(7)
L2
L2
L2
L1
L2
L1
L1
Ph
Ph
Ph
Me
Me
Me
Me
Me
Me
Me
Me
Me
Et
OPh
OPh
OPh
–
OPh
–
Et
–
KL1
KL2
R42SnL12
R42SnL22
1:2
−→
r.t.
R42SnCl2 +
+ 2KCl
Compd.
L
R1
R2
R3
R4
(8)
(9)
(10)
(11)
L1
L1
L2
L2
Me
Me
Me
Me
Me
Et
Me
Me
–
–
OPh
OPh
n-Bu
n-Bu
Ph
n-Bu
1:2
[(PhCMe2CH2)3Sn]2O + HL −→ (PhCMe2CH2)3SnL + H2O
reflux
Compd.
L
R1
R2
R3
(12)
(13)
(14)
L2
L2
L1
Ph
Me
Me
Me
Me
Et
OPh
OPh
–

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88
LI ET AL.

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ORGANOTIN PYRAZOLECARBOXYLATES
89
Table 2. Infrared Frequencies (cm−1) of Organotin Derivatives of Pyrazolecar-
boxylic Acid
Compd.
νasym(CO2)
νsym(CO2)
ꢀν (CO2)
ν(Sn−O)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
1615 s
1629 s
1635 s
1616 s
1601 s
1624 s
1624 s
1575 s
1581 s
1589 m
1592 s
1631 s
1636 s
1652 s
1345 s
1345 m
1344 s
1322 s
1350 m
1327 s
1330 s
1349 s
1344 s
1413 m
1419 m
1358 s
1340 s
1311 s
270
284
291
294
251
297
294
226
237
176
173
273
296
341
457 m
465 m
445 m
453 s
459 m
461 s
470 w
456 m
473 s
458 m
465 m
474 m
475 m
468 m
s: Strong; m: Medium; w: Weak.
IR Spectra
The IR spectra of these compounds have been recorded in the range of
400–4000 cm−1. Tentative assignments have been made on the basis of earlier
publications and the important data are listed in Table 2. The IR spectra of all
of the organotin(IV) compounds do not show a strong band in 3500–3300 cm−1
region, due to ν(OH), indicating deprotonation and coordination of the carboxylate
group with tin metal as expected.
The vacant 5d orbital of tin atoms tends toward high coordination with
ligands containing lone pairs of electrons. The IR stretching frequencies of the
carboxylate groups are very important for determining their structures: when there
are interactions between the carbonyl oxygen atoms of the carboxylate groups
and the tin atom, the asymmetric absorption vibration frequencies νasym(CO2) of
carboxylate groups decrease and the symmetric absorption frequencies νsym(CO2)
increase. Their difference [ꢀν (CO2)] therefore decreases (11–13). In the IR spec-
tra of the title compounds the carboxylate bands are observed in the characteristic
regions for νasym(CO2) between 1640 and 1575 cm−1 and νsym(CO2) between 1419
and 1311 cm−1 (see Table 2).
In the triorganotin(IV) derivatives the differences [ꢀν (CO2)] between νasym
(CO2) and νsym(CO2) are more than 200 cm−1 indicating the covalent nature of the
metal–oxygen bond (14). Ionic bonding and also bridging or chelation, therefore,
can be excluded, and unidentate coordination of the carboxylic groups bonding to

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LI ET AL.
the metal must be assumed (15). In the diorganotin(IV) derivatives the frequencies
νsym(CO2) are shifted to higher wave numbers as compared to those of the free
acids. ꢀν (CO2) in the diorganotin derivatives is smaller than ꢀν (CO2) in the
triorganotin derivatives and this may be attributed to steric crowding around the
tin atom. Thus, for compounds (10) and (11), ꢀν (CO2) is less than 200 cm−1
;
this indicates that the carboxylate groups are chelated and bonded to the metal
bidentately (16). In addition, the frequencies ν(Sn−O) appear between 453 and
473 cm−1. This is consistent with the literature values (425–520) cm−1) (16–18).
1H NMR Spectra
The chemical shifts of various protons in the compounds are given in Table 3.
The conclusions drawn from the 1H NMR spectral studies lend further support to
the mode of bonding discussed above. The absence of signals between 10.00 and
13.00 ppm due to the CO(OH) proton suggests the deprotonation of the carboxylic
Table 3. 1H NMR Chemical Shifts (δ ppm; J Hz) of R4n Sn(L)4−n
Compd.
R1
R2
R3
R4
(1)
(2)
(3)
(4)
(5)
(6)
6.85–7.65 (m, 5H) 2.57 (s, 3H)
6.89–7.22 (m, 5H) 2.55 (s, 3H)
6.88–7.59 (m, 5H) 2.53 (s, 3H)
6.85–7.65 (m, 5H) 6.85–7.65 (m, 15H)
6.89–7.22 (m, 5H) 1.22–1.74 (m, 33H)
6.88–7.59 (m, 5H) 0.81–1.48 (m, 27H)
7.42–7.78 (m, 15H)
6.94–7.58 (m, 5H) 6.94–7.58 (s, 15H)
7.45–7.80 (m, 15H)
3.77 (s, 3H)
3.64 (s, 3H)
4.08 (s, 3H)
2.47 (s, 3H)
2.52 (s, 3H)
2.62 (q, 7.6, 2H)
1.21 (t, 7.6, 3H)
2.60 (q, 7.4, 2H)
1.21 (t, 7.4, 3H)
2.44 (s, 6H)
2.63 (q, 7.3, 4H)
1.22 (t, 7.3, 6h)
2.44 (s, 6H)
(7)
4.06 (s, 3H)
1.31–1.98 (m, 33H)
(8)
(9)
3.79 (s, 6H)
4.09 (s, 6H)
0.61–1.76 (m, 18H)
0.63–1.76 (m, 18H)
(10)
(11)
(12)
3.63 (s, 6H)
3.62 (s, 6H)
6.67–7.62 (m, 10H) 6.67–7.62 (m, 10H)
6.86–7.25 (m, 10H) 0.68–1.33 (m, 18H)
6.98–7.67 (m, 5H) 6.98–7.67 (m, 15H)
1.16 (s, 18H)
2.42 (s, 6H)
6.98–7.67 (m, 5H) 2.65 (s, 3H)
1.14 (s, 6H)
(13)
(14)
3.57 (s, 3H)
4.03 (s, 3H)
2.46 (s, 3H)
6.87–7.24 (m, 5H) 6.87–7.24 (m, 15H)
1.06 (s, 18H)
1.03 (s, 6H)
7.06–7.27 (m, 15H)
1.22 (s, 18H)
2.62 (q, 7.4, 2H)
1.24 (t, 7.4, 3H)
1.26 (s, 6H)

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ORGANOTIN PYRAZOLECARBOXYLATES
91
group of the ligands. The signals due to the aromatic protons of organotin pyra-
zolecarboxylate are complex and are observed between 6.67 and 7.78 ppm. All
protons in the compounds have been identified and agree with those calculated
from the expected molecular formula.
Mass Spectra
The mass spectra of compounds (4) and (9) were recorded. For compound (4)
the molecular ion peak 524 (M+) is observed but for compound (9) the molecular
ion peak is not observed. Decarboxylation and dephenylation from the tin atom
are the two main breakdown patterns for the two compounds [e.g. for compound
(4) (m/z, relative intensity): Ph3Sn+ (351, 3.86), PhSn+ (197, 45.89), R+ꢁCOO+
(173, 25.74); for compound (9): Bu2SnO2CRꢁ+ (407, 2), BuSn(O2CRꢁ)2 (523,
23), Bu+ (57, 39)].
Supported Structures of the Complexes
Based on the above analytical studies and earlier publications (3,19,20), the
proposed structures of the complexes are shown in Figure 2.
Antibacterial Activity
Selected title compounds were evaluated for their antibacterial activity using
the paper disc method (21) against the bacteria Gibbereila zeae, Alternaria solani,
Rhizoctonia solani, and Physolospora piricola at 50 ppm concentration in acetone
as solvent in vitro. The results of the antibacterial activity are given in Table 4.
These results indicate that all selected compounds have antibacterial activity for the
four bacteria. Triorganotin derivatives have relatively higher antibacterial activity
R4
R4
Sn R4
R4
O
O
O
O
O
R2
N
R2
N
R2
C
C
O
C
Sn
R4
R3
R3
N
R3
N
N
N
R1
R1
R1
Figure 2. Proposed structures of the complexes.

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LI ET AL.
Table 4. Antibacterial Activity of Selected Compounds
Inhibition Ratio (%)
Compd.
G. zeae
A. solani
R. solani
P. piricola
(1)
(3)
(4)
(5)
(6)
(11)
(12)
(13)
(14)
68.0
61.1
76.9
100.0
48.0
18.8
23.1
42.3
73.8
40.0
50.2
61.8
100.0
46.7
7.3
13.6
36.6
63.6
60.0
100.0
80.1
100.0
57.1
28.8
27.1
42.4
69.5
100.0
60.0
94.1
100.0
66.7
38.2
35.3
42.1
91.2
than diorganotin derivatives. Compound (5) has a very high antibacterial activity,
the inhibition ratios are 100% for all four bacteria.
ACKNOWLEDGMENT
We are thankful to Professor Bingwu Li of the National Laboratory of
Elemento-Organic Chemistry in Nankai University, for testing the antibacterial
activity.
REFERENCES
1. Davis, A.G.; Smith, P.J.; Wilkinson, G.; Stone, F.G.A.; Abel, E.W. Eds.
Comprehensive Organometallic Chemistry; Pergamon Press: Oxford, 1982;
Vol. 2.
2. Omae, I. Organotin Chemistry, J. Organomet. Chem. Library Elsevier,
Amsterdam, 1989; Vol. 21.
3. Song, X.Q.; Yang, Z.Q.; Xie, Q.L.; Li, J.S. J. Organomet. Chem. 1998, 566,
103.
4. Nath, M.; Yadav, R.; Eng, G.; Nguyen T.T.; Kumar, A. J. Organomet. Chem.
1979, 577, 1.
5. Blunden, S.J.; Cussack, P.A.; Hill, R. The Industrial Use of Tin Chemicals;
Royal Society of Chemistry: London, 1985.
6. Hideo, T.; Horoshi, H.; Akira, N.; Kuniaki, Y. Jpn. Kokai. Tokkyo Koho JP,
62 53, 970 (1987); Chem. Abstr. 1987, 107, P96714n.
7. Huppatz, J.L. Aust. J. Chem. 1983, 36, 135.

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REPRINTS
ORGANOTIN PYRAZOLECARBOXYLATES
93
8. Collins, J.D.; Jones, T.E. US Patent 4, 113, 758, 1979; CA 1979, 90, 23257m.
9. Chambers, R.; Scherer, P. J. Am. Chem. Soc. 1926, 48, 1054.
10. Kozeschkov, K.A.; Nadj, M.M.; Alexandrow, A.A. Ber. 1934, 67, 1348.
11. Doak, G.O.; Long, G.G.; Freedman, L.D. J. Organomet. Chem. 1965, 4, 82.
12. Singhal, K.; Rastogi, R.; Raj, P. Indian J. Chem. 1987, 26A, 146.
13. Glowacki, A.; Huber, F.; Preut, H. Recl. Trav. Chim. Pays-Bas 1988, 107,
278.
14. Nath, M.; Goyal, S.; Goyal, S.; Eng, G.; Ogwura, N. Synth. React. Inorg.
Met.-Org. Chem. 1998, 28, 1619.
15. Roge, G.; Huber, F.; Preut, A.; Silvestri, A.; Barbieri, R. J. Chem. Soc., Dalton
Trans. 1983, 595.
16. Sandhu, G.K.; Gupta, R.; Sandhu, S.S.; Parish, R.V. Polyhedron 1985, 4, 81.
17. Sandhu, G.K.; Hundal, R.; Tiekink, E.R.T. J. Organomet. Chem. 1991,
412, 31.
18. Shavma, N.; Prem, P.; Sharama, V.; Blatt, S.S.; Chaudhry, S.C. Synth. React.
Inorg. Met.-Org. Chem. 1997, 27, 1381.
19. Tiekink, E.R.T. Appl. Organomet. Chem. 1994, 5, 1.
20. Kushlefsky, B.; Simmons, I.; Ross, A. Inorg. Chem. 1963, 2, 187.
21. Keshavan, B.; Radhika, R.T. Synth. React. Inorg. Met.-Org. Chem. 1999, 29,
1339.
Received April 28, 2000
Accepted September 1, 2000
Referee I: D. Rabinovich
Referee II: T. R. Webb

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