Synthesis, characterization and antibacterial activity of organotin(IV) complexes derivatives of 2-chloro-4-nitrobenzoic acid

Article abstract of DOI:10.14233/ajchem.2014.16066

Four organotin(IV) carboxylate complexes have been successfully synthesized and characterized quantitatively and qualitatively. Spectroscopic studies showed that the coordination took place via oxygen atoms from the carboxylate anions. With the exceptiona

Full text of DOI:10.14233/ajchem.2014.16066

Asian Journal of Chemistry; Vol. 26, No. 10 (2014), 2949-2953
ASIAN JOURNAL OF CHEMISTRY
http://dx.doi.org/10.14233/ajchem.2014.16066
Synthesis, Characterization and Antibacterial Activity of Organotin(IV)
Complexes Derivatives of 2-Chloro-4-nitrobenzoic Acid
1
1,*
1
2
CHEN-SHANG CHOONG , YIP-FOO WIN , SIE-TIONG HA and EMAD YOUSIF
1Department of Chemical Science, Faculty of Science, Universiti TunkuAbdul Rahman, Perak Campus, Jalan Universiti, Bandar Barat, 31900
Kampar, Perak, Malaysia
2Department of Chemistry, College of Science, Al-Nahrain University, Baghdad, Iraq
*Corresponding author: Fax: +60 5 4661676; Tel: +60 5 4688888; E-mail: williamyfw@yahoo.com
Received: 18 July 2013;
Accepted: 22 November 2013;
Published online: 10 May 2014;
AJC-15155
Four organotin(IV) carboxylate complexes have been successfully synthesized and characterized quantitatively and qualitatively.
Spectroscopic studies showed that the coordination took place via oxygen atoms from the carboxylate anions. With the exceptional case,
spectroscopic studies indicated that one methanol molecule also take part in the coordination to tin(IV) atom moiety in complex 4
resulting the tin(IV) atom exhibited five coordination. From the preliminary in vitro antibacterial screening activity, triphenyltin(IV)
(complex 4) showed some significant activity compared to diorganotin(IV) complexes (1-3).
Keywords: Organotin(IV) carboxylate, 2-Chloro-4-nitrobenzoic acid.
1H-13C HMQC and 119Sn NMR were recorded on a Joel JNM-
ECX 400 FT-NMR Spectrometer using deuterated CDCl3 and
INTRODUCTION
The coordination chemistry of organotin(IV) complexes
are extensively studied due to its coordination geometries as
d6-DMSO as the solvent and tetramethylsilane, TMS as the
internal standard. Elemental C, H and N analyses were carried
well as structural diversity which could expand from simple
out on a Perkin-Elmer 2400 CHN Elemental Analyzer. The
monomer and dimeric to hexameric, oligomeric and polymeric
structures1-6. In general, it was also well-documented that the
uncorrected.
melting points were determined in an open capillary and were
participation of coordinating solvent molecules such as water,
acetone and methanol to tin(IV) atoms moieties and its coordi-
Preparation of dimethyltin(IV) oxide, Me2SnO:
Dimethyltin(IV) dichloride was dissolved in distilled water
nation sphere will influence the overall structure of organotin(IV)
and stirred for 16 h. Colourless solution was obtained.Ammonia
solution (60 %) was added into the colourless solution and
complexes including its 3D crystal structure packing3,4,6,7. Up-
to-date, numerous studies on organotin(IV) complexes have
finally white precipitate was obtained. The precipitate was
been carried out in order to study its biological properties against
bacterial strains and cancer cell lines to explore its structural-
placed in an oven (60 °C) for a few days to dry.
Preparation of sodium salt: The sodium salt of the acid
activity relationship8-15
.
was obtained by heating under reflux a 1:1 molar mixture of
sodium hydroxide, NaOH and 2-chloro-4-nitrobenzoic acid
in ethanol (50 mL) for 2 h.After a few days, white precipitates
were obtained. Sodium salt of 2-chloro-4-nitrobenzoic acid:
FTIR as KBr disc (cm-1) selected data: ν(COO)as 1617,
ν(COO)s 1356, ∆ν = 262.
In this paper, we report on the synthesis and structural
characterization of new organotin(IV) carboxylate complexes
derived from 2-chloro-4-nitrobenzoic acid, HL as well as the
preliminary in vitro antibacterial screening activity of the comp-
lexes.All the important results obtained were reported herein.
EXPERIMENTAL
Synthesis of complexes
Preparation of (2-Cl-4-NO2-C6H3COO)2(CH3)2Sn (1):
Complex 1 was obtained by heating under reflux a 1:2 molar
mixture of dimethyltin(IV) oxide (0.33 g, 2 mmole) and 2-
chloro-4-nitrobenzoic acid (0.81 g, 4 mmole) in acetonitrile
(50 mL) for 4 h. A clear colourless transparent solution was
All the reagents, starting materials as well as the solvents
were purchased commercially and used without any further
purification. The infrared spectra were recorded using a Perkin-
Elmer System 2000 FTIR Spectrophotometer as a KBr disc in
the frequency range of 4000-400 cm-1. The spectra for 1H, 13C,

2950 Choong et al.
Asian J. Chem.
separated by filtration and kept in a bottle. After few days,
transparent solids (0.73 g, 66.7 % yield) were collected. m.p.:
180.3-182.9 °C. Analysis for C16H12N2O8Cl2Sn1: C, 34.08; H,
1.93; N, 5.11 %. Calculated for C16H12N2O8Cl2Sn1 C, 34.95;
H, 2.20; N, 5.09 %. FTIR (KBr disc, cm-1): ν(C-H) aromatic
3048, ν(C-H) saturated 2931; ν(COO)as 1717; ν(COO)s 1349,
∆ν = 368; ν(NO2) 1528, ν(O-Sn-O) 624, ν(Sn-C) 544, ν(Sn-
O) 492. 1H NMR (ppm) (CDCl3): δ: benzene protons 8.16 (d,
8.7 Hz, 2H); 8.20 (dd, 2.3 Hz, 6.4 Hz, 2H); 8.36 (d, 1.8 Hz,
solution was isolated by filtration and kept in a bottle. After
few days, transparent crystals (0.71 g, 69.5 % yield) were
collected. m.p.: 115.6-116.6 °C.Analysis for C26H22N1O5ClSn:
C, 53.45; H, 3.74; N, 2.33 %. Calculated for C26H22N1O5Cl1Sn1:
C, 53.60; H, 3.81; N, 2.40 %. FTIR (KBr disc, cm-1): ν(C-H)
aromatic 3072, 3052; ν(C-H) saturated 2979, ν(COO)as 1618,
ν(COO)s 1345, ∆ν = 273; ν(NO2) 1522, ν(Sn-O) 457. 1H NMR
(ppm) (d6 DMSO): δ: phenyl protons 7.41-7.48 (m, 9H); 7.86-
7.88 (m, 6H); benzene 7.60 (d, 8.5 Hz, 1H); 8.12 (dd, 2.3 Hz,
6.6 Hz, 1H); 8.19 (d, 2.3 Hz, 1H); CH3OH 3.18 (d, 4.8 Hz,
3H), 4.15 (q, 5.0 Hz, 1H). 13C NMR (ppm) (d6-DMSO): δ:
phenyl carbons Cipso 142.73 (798.0 Hz), Cortho 136.26 (45.4
Hz), Cmeta 128.44 (69.5 Hz), Cpara 129.11; benzene 122.24,
124.92, 129.44, 130.25, 131.00, 147.67; CH3OH 48.72; COO
167.61. 119Sn-NMR (ppm) (d6-DMSO): δ: -261.65.
13
2H); methyl 1.30 (s, 6H), 2J(119Sn-1H) = 81.1 Hz. C NMR
(ppm) (CDCl3): δ: benzene carbons 121.48, 126.30, 133.06,
134.52, 135.71, 149.87; methyl 5.48, COO 170.42. 119Sn NMR
(ppm) (CDCl3): δ: -97.20.
Preparation of (2-Cl-4-NO2-C6H3COO)2(C4H9)2Sn (2):
Complex 2 was obtained by heating under reflux a 1:2 molar
mixture of dibutyltin(IV) oxide (0.50 g, 2 mmole) and 2-
chloro-4-nitrobenzoic acid (0.81 g, 4 mmole) in ethanol
(50 mL) for 4 h. A clear colourless transparent solution was
separated by filtration and kept in a bottle. After few days,
transparent solids (0.86 g, 67.8 % yield) were collected. m.p.:
115.6-116.6 °C. Analysis for C22H24N2O8Cl2Sn: C, 41.98; H,
4.06; N, 4.43 %. Calculated for C22H24N2O8Cl2Sn1: C, 41.67;
H, 3.82; N, 4.42 %. FTIR (KBr disc, cm-1): ν(C-H) aromatic
3082, ν(C-H) saturated 2961, 2934, 2868; ν(COO)as 1602;
ν(COO)s 1347, ∆ν = 255; ν(NO2) 1554, ν(O-Sn-O) 640, ν(Sn-
2-Chloro-4-nitrobenzoic acid, HL: The parent acid, 2-
chloro-4-nitrobenzoic acid, HL was purchased from Acros
Organics and used without any further purification. FTIR (KBr
disc, cm-1): selected data: ν(OH) 2823-2577, ν(COO)as 1708,
1
ν(COO)s 1356, ∆ν = 353. H NMR (ppm) (d6-DMSO): δ:
benzene protons 7.98 (d, 8.7 Hz, 1H); 8.23 (dd, 1.8 Hz, 4.1
Hz, 1H); 8.33 (d, 2.3 Hz, 1H). 13C NMR (ppm) (d6-DMSO):
δ: benzene carbons 122.84, 125.82, 131.99, 132.63, 138.11,
149.42; COO 166.26.
Preliminary in vitro antibacterial screening activity:
The synthesized complexes 1-4 and acid, 2-chloro-4-nitro-
benzoic acid were screened for their in vitro antibacterial activity
against two Gram-negative [Escherichia coli (ATCC 25922)
and Pseudomonas aeruginosa (ATCC 27853)] and two Gram-
positive [Bacillus subtilis (ATCC 38583) and Staphylococcus
aureus (ATCC 25923)] bacterial strains by Inhibition Zone
Method using paper disc diffusion method16-17. The seeded agar
(nutrient agar medium) was prepared by cooling the molten
agar to 40 °C and then adding bacterial inoculums containing
approximately 1 × 104-108 colony forming units (CFU)/mL.
The bacterial inoculums were spread on the plate containing
agar medium and even coverage was ensured before the agar
solidified. The complexes were dissolved in DMSO to prepare
1.0 mg/mL concentration. Later, small filter paper discs (6 mm)
containing 1.0 mg/mL of the samples were laid on the growth
medium. The plates were incubated immediately at 37 °C for
20-24 h. The activity was determined by measuring the diameter
of the inhibition zone (in mm).
1
C) 520, ν(Sn-O) 485. H NMR (ppm) (CDCl3): δ: benzene
protons 8.13 (d, 8.3 Hz, 2H); 8.19 (dd, 1.8 Hz, 6.4 Hz, 2H);
8.33 (d, 2.3 Hz, 2H); butyl, CH3 0.95 (t, 7.4 Hz, 6H), CH2
1.48 (sx, 7.3 Hz, 4H); CH2 1.84 (qn, 7.3 Hz, 4H); CH2 1.98 (t,
8.7 Hz, 4H). 13C NMR (ppm) (CDCl3): δ: benzene carbons
121.53, 126.09, 132.75, 135.09, 136.02, 149.59; butyl 13.63,
26.41, 26.75, 26.90; COO 173.30. 119Sn-NMR (ppm) (CDCl3):
δ: -123.40.
Preparation of [{2-Cl-4-NO2-C6H3COO(C4H9)2Sn}2O]2
(3): Complex 3 was obtained by heating under reflux a 1:1
molar mixture of dibutyltin(IV) oxide (0.50 g, 2 mmole) and
2-chloro-4-nitrobenzoic acid (0.41 g, 2 mmole). The reaction
was carried out in a mixture of ethanol (60 mL) for 3 h. A
clear transparent solution was isolated by filtration and kept
in a bottle. After few days, colourless crystals (0.73 g, 83.7 %
yield) were collected. m.p.: 175.4-176.5 °C. Analysis for
C60H84N4O18Cl4Sn4: C, 41.22; H, 4.47; N, 3.20 %. Calculated
for C60H84N4O18Cl4Sn4: C, 40.81; H, 4.79; N, 3.17 %. FTIR
(KBr disc, cm-1): ν(C-H) aromatic 3100, 3065; ν(C-H) satu-
rated 2960, 2928, 2861; ν(COO)as 1594, ν(COO)s 1342, ∆ν =
252; ν(NO2) 1530, ν(Sn-O-Sn) 624, ν(Sn-C) 519, ν(Sn-O)
468. 1H NMR (ppm) (CDCl3): δ: benzene protons 7.72 (d, 7.8
Hz, 4H); 8.16 (d, 8.24 Hz, 4H); 8.29 (d, 1.8 Hz, 4H); butyl,
CH3 0.86 (t, 7.4 Hz, 12H), 0.91 (t, 7.4 Hz, 12H); CH2 1.28-
1.45 (m, 16H); CH2 1.56-1.78 (m, 32H). 13C NMR (ppm)
(CDCl3): δ: benzene carbons 121.65, 125.82, 130.28, 133.08,
140.16, 148.65; butyl 13.63, 26.74, 26.79, 27.37, 27.56, 28.75,
30.16; COO 170.62. 119Sn NMR (ppm) (CDCl3): δ: -183.76,
-197.49.
RESULTS AND DISCUSSION
In this study, complexes 1-4 have been obtained in solid
state. Complexes 1-4 gave a sharp melting point indicating
the isolation of fairly pure complexes. An outline of the
proposed structure for complexes 1-4 were depicted in Fig. 1.
The micro-elemental analysis for C, H and N data obtained
were in agreement with the predicted formula for complexes
1-4. Based on the micro-elemental analysis, it was believed
that a methanol molecule was present in complex 4 which
acted as a solvate molecule in those similar reported comp-
lexes3,4,6,7. This phenomenon has already been clarified and
the X-ray crystal structure of complex 4 has been reported4.
The ν(O-H) bands of the acid, 2-chloro-4-nitrobenzoic
acid was absent in the infrared spectra of salt and complexes
Preparation of 2-Cl-4-NO2-C6H3COO(C6H5)3Sn.-
CH3OH (4): The title complex was obtained by heating under
reflux a 1:1 molar mixture of triphenyltin(IV) hydroxide
(0.73 g, 2 mmole) and 2-chloro-4-nitrobenzoic acid (0.41 g,
2 mmol) in methanol (50 mL) for 2 h. A clear transparent

Vol. 26, No. 10 (2014)
Synthesis, Characterization and Antibacterial Activity of Organotin(IV) Complexes Derivatives 2951
Me
O
O
O
O
Sn
NO2
+ H2O
NO2
HOOC
O2N
Me2SnO
+
C
C
2
2
Me
Cl
Cl
Cl
1
Bu
Sn
Bu
O
O
O
O
NO2
NO2
+ H2O
HOOC
O2N
Bu2SnO
+
C
C
Cl
Cl
Cl
Cl
2
Bu
Bu
Cl
Sn
C
O
NO2
O
O2N
C
O
O
O
Bu
Bu
Bu
Bu
Sn
Sn
NO2
+ 2H2O
4HOOC
+
Bu2SnO
4
O
Cl
O
C
O
C
NO2
Sn
O
O
O2N
Cl
Cl
Bu
Bu
3
Ph
O
methanol
NO2
HOOC
Ph Sn
+
+ H2O
Ph3SnOH
NO2
C
O
Ph
Cl
Me methyl, Bu butyl & Ph = phenyl
Cl
CH3OH
4
=
=
Fig. 1. Proposed structure for complexes 1-4
1-4 showed that the deprotonation and coordination of the
carboxylate anion. In addition, complexes 1-4 (except complex
1) revealed that the ν(COO)as was shifted to a lower wavelength
number compared to the acid, 2-chloro-4-nitrobenzoic acid
which signified that the coordination took place via the oxygen
atoms of the carboxylate anion. Complex 1 was isolated as a
monomeric type and its ∆ν was 368 cm-1 which was higher
than the sodium salt (∆ν = 262 cm-1) of 2-chloro-4-nitrobenzoic
acid, indicating that the carboxylate anions were coordinated
to the tin(IV) atom moiety in a monodentate manner and exhi-
bited four coordination number18. From the infrared spectra
of complexes 2 and 3, both of the ∆ν values (complex 2 = 255
cm-1, complex 3 = 252 cm-1) were comparable and lower than
the ∆ν of the sodium salt indicating that all the carboxylate
anions were bonded to the tin(IV) atoms in a bidentate mode18.
Hence, as an early structure determination, the tin(IV) atom
in complex 2 was six-coordinated and exhibited distorted
octahedral geometry. Moreover, since all the carboxylate anions
in complex 3 were bonded in bidentate manner, as a result,
two tin(IV) atoms exhibited a distorted trigonal bipyramidal
geometry and while another two tin(IV) atoms exhibited a
distorted octahedral geometry. For complexes derived from
triphenyltin(IV) carboxylate, ∆ν greater than 200 cm-1 would
be expected for the monodentate bonding carboxylate anions19.
Hence, the carboxylate anion in complex 4 would be expected
to bond to the tin(IV) atom in monodentate manner since the
∆ν above 200 cm-1. Based on the micro-elemental analysis
and crystal structure study, a methanol molecule was present
in complex 4. As a result the absorption bands of the aliphatic
and aromatic functional groups centered around 3000 cm-1
appeared as though they were sitting on a small hump together
with the ν(OH) band in the spectra of complexes 4. Hence,
the tin(IV) atom of complex 4 was five-coordinated and
exhibited a trigonal bipyramidal geometry. For further evidence
of the coordination to tin(IV) atom via oxygen atoms was
revealed by the presence of the ν(O-Sn-O)/ν(Sn-O-Sn) and
ν(Sn-O) stretching bands which could be found in the
wavelength number at 640-624 and 492-457 cm-1, respectively
in the spectra of complexes 1-4.
1
The H NMR spectra of complexes 1-4 exhibited simi-
larities to their acid, 2-chloro-4-nitrobenzoic acid. In the
upfield regions of the 1H NMR spectra of the complexes 1-3
showed the signal of the methyl and butyl protons of the
organotin(IV) at 1.30 ppm and in the range of 0.86-1.93 ppm,

2952 Choong et al.
Asian J. Chem.
respectively. Complex 1 exhibited a sharp singlet in the upfield
2
indicating that the tin(IV) atom in complex 1 remained four-
coordinated whereas the tin(IV) atom in complex 2 was five-
coordinated. This may be due to the disassociation of one
bidentate bond upon dilution during the preparation of NMR
study. Complexes derivatives of organodistannoxane dimer
types usually exhibit two well resolved δ(119Sn) signals
(complex 3 = -183.77, -197.49 ppm). Based on the 119Sn NMR
spectra, all the tin(IV) atoms in complex 3 were five-
coordinated and each exhibited a distorted trigonal bipyramidal
geometry. This is due to the same phenomenon that happened
in complex 2. Normally, the δ(119Sn) value of triphenyltin(IV)
complexes lie in the range between -180 to -260 ppm was
believed to be five-coordinated and in the distorted trigonal
bipyramid geometry [ Ph3SnX·L (L is a monodentate ligand)].
Complex 4 showed that the δ(119Sn) value at -261.66 ppm
which lie slightly upfield in the range of -180 to -260 ppm
indicated the tin(IV) atom was five-coordinated and possessed
a trans-trigonal bipyramid geometry23-24. From the 119Sn NMR
study, it is strongly to conclude that the methanol molecule
(coordinating solvent) was coordinated to the tin(IV) atom in
complex 4 resulting the tin(IV) atom being five-coordinated.
Preliminary in vitro antibacterial screening activity:
The preliminary in vitro antibacterial screening activity of acid,
2-chloro-4-nitrobenzoic acid and complexes 1-4 were given
in Table-1. Inhibition zones with a diameter less than 10 mm
are considered as weak; larger than 10 mm but less than 16
mm are considered as moderate and finally larger than 16 mm
and above are active. Based on the study, acid, HL were found
to be inactive and complexes 1-3 showed a weak to moderate
activity to all the tested bacterial strains. In addition, complex
4 was found to show selective activity against Bacillus subtillis
and Staphylococcus aureus at 1.0 mg/mL with the inhibition
zones obtained for complex 4 were 23 and 21 mm, respectively
indicating that the preliminary in vitro antibacterial activity
was in the active mode. Moreover, the inhibition zone diameters
of complexes 1-3 in the range of 8-15 mm indicated that their
activities were weak to moderate. Hence, the triphenyltin(IV)
complexes were more active compared to diorganotin(IV)
complexes derivatives against Gram-positive bacterial strains.
This phenomenon was due to complex 4 was derivatives of
triorganotin(IV) which is known to possess higher biological
activity compared to diorganotin(IV); the tin(IV) atom moiety
of complex 4 was five-coordinated and exists in a trans-R3SnO2
geometry in solution form hence causing its activity of be greater
compared to complexes 1-322,27. In addition, it was believed
region with the J(119Sn-1H) value of 81.1 Hz. Based on the
Lockhart-Manders equation, the C-Sn-C angles of complex 1
was 132.2°20. Hence, the tin(IV) atom of complex 1 was not
six-coordinated and should be four-coordinated based on the
infrared spectroscopy study. For complex 4, the resonances
appeared as two well separated sets of multiplets in the regions
centering around δ = 7.44 and 7.87 ppm (downfield) with the
integration values of 9:6, respectively, ascribed to the aromatic
protons of the phenyl group21. Based on the 1H NMR spectral
studies of complex 4, the proton resonances originating from
the methanol molecule occurred at δ = 3.18 and 4.15 ppm;
based on the integration, only one methanol molecule was
present in complex 4.
Evidence of the formation of the complexes was displayed
in the 13C NMR spectra. The 13C NMR spectra of complexes
1-4 showed that the δ(COO) signals shifted to the downfield
region which was lower compared to that of the acid, 2-chloro-
4-nitrobenzoic acid indicating the carboxylate anions were
bonded to tin(IV) atoms. Complex 1 exhibited a sharp signal
at 5.48 ppm indicating the presence of the methyl groups in
the SnMe2 moiety whereas complex 2 exhibited four sharp
signals at 13.63, 26.41, 26.75 and 26.90 ppm indicating the
presence of the butyl groups of the SnBu2 moiety. Moreover,
complex 3 was derivatives of organodistannoxane dimer types
exhibited two sets of signals corresponding to the butyl groups
in the 13C NMR spectra as observed in complex 2. These two
sets of signals were attributed to the butyl groups linked to the
exo- and endo-cyclic tin(IV) atoms respectively22. Complex 4
revealed the chemical shifts of the δ(13C)ipso at 142.73 ppm
indicative of a five-coordinated tin(IV) atom23-25. Complex 4
also showed that the 1J(119Sn-13C) value of 798.0 Hz lie in the
range of 750-850 Hz, thus indicating that the tin(IV) atom in
complex 4 was five-coordinated and has a trans-trigonal
bipyramid geometry24. In addition, in the 13C NMR spectra of
complex 4, the signals due to the methanol molecule was
located at the upfield region at δ = 48.72 ppm. This indicated
that the methanol molecule bonded strongly to the tin(IV) atom
without any disassociation upon dilution during the preparation
of liquid state NMR study.
The δ(119Sn) values of the four-coordinated complexes fall
in the range between +200 to -60 ppm; the five-coordinated
complexes between -90 to -190 ppm and the six-coordinated
complexes between -210 to -400 ppm26. The δ(119Sn) values of
complexes 1 and 2 were -97.20 and -123.40 ppm, respectively
TABLE-1
PRELIMINARY in vitro ANTIBACTERIAL SCREENING ACTIVITY OF
2-CHLORO-4-NITROBENZOIC ACID AND COMPLEXES 1-4
Complexes
Inhibition Zone (mm)
Bacillus subtilis
Escherichia coli
Pseudomonas aeruginosa
Staphylococcus aureus
2-Chloro-4-nitrobenzoic acid (HL)
-
-
-
-
1
10
15
15
23
27
35
24
8
9
8
2
11
11
9
9
11
12
21
19
36
28
3
25
20
9
4
Chloramphenicol
Doxycycline
Rifampicin
8
23
16
25
14
Paper disc diffusion method (in vitro) = 1.0 mg/mL; Reference drug = Chloramphemicol, Doxycycline and Rifampicin

Vol. 26, No. 10 (2014)
Synthesis, Characterization and Antibacterial Activity of Organotin(IV) Complexes Derivatives 2953
9. R. Willem,A. Bouhdid, B. Mahieu, L. Ghys, M. Biesemans, E.R.T. Tiekink,
that the coordinated methanol molecule aided the transpor-
tation of active triphenyltin(IV) to the cell or active sites (receptor
sites) which enhanced its biological activity28-30. Although
complex 4 showed significant in vitro antibacterial activity
against Gram-positive bacterial strains but the value obtained
were lower compared to the reference drugs.
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Conclusion
Complexes 1-4 have been successfully synthesized. The
structural as well as the coordination number of tin(IV) atoms
moieties of complexes 1-4 have been successfully characterized
quantitatively and qualitatively. Based on the preliminary in vitro
antibacterial screening activity, complex 4 [triphenyltin(IV)]
showed better activity compared to complexes 1-3 [diorga-
notin(IV)] against Gram-positive bacterial strains but lower
activity compared to the reference drugs.
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ACKNOWLEDGEMENTS
The authors would like to thank Universiti Tunku Abdul
Rahman (UTAR) for the UTAR Research Fund (Project No.
IPSR/RMC/UTARRF/C1-11/C07) for financial support as well
as technical assistance and facilities.
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