Platinum (IV) thiohydrazide, thiodiamine and thiohydrazone complexes: A spectral, antibacterial and cytotoxic study

Article abstract of DOI:10.1016/j.saa.2006.04.038

Some platinum (IV) complexes [Pt(L)₂Cl₂] [where, L = 2-aminopyridine-N-thiohydrazide (L¹), (2-aminopyridine-N-thio)-1,3-propanediamine (L²), benzaldehyde-2-aminopyridine-N-thiohydrazone (L³) and salicylaldehyde-2-aminopyrtidine-N-thiohydrazone (L⁴)] have been synthesized. The thiohydrazides, thiodiamine and thiohydrazones can exist as thione-thiol tautomer and coordinate as a bidentate N-S ligand. The ligands found to act in monobasic bidentate fashion. Analytical data reveals that metal to ligand stoichiometry is 1:2. The complexes have been characterized by elemental analysis, IR, mass, electronic and ¹H NMR spectroscopic studies. In vitro antibacterial and cytotoxic study have also been carried out for some complexes.

Full text of DOI:10.1016/j.saa.2006.04.038

Spectrochimica Acta Part A 66 (2007) 1042–1047
Platinum (IV) thiohydrazide, thiodiamine and thiohydrazone complexes:
A spectral, antibacterial and cytotoxic study
A.K. Mishraa, S.B. Mishrab, N. Manava, R. Kumarc, Sharadc,
R. Chandrac, D. Salujac, N.K. Kaushika,∗
a Department of Chemistry, University of Delhi, Delhi 110007, India
b Department of Chemistry, University of the Free State-9866, South Africa
c Ambedkar Centre for Biomedical Research, University of Delhi, Delhi 110007, India
Received 27 March 2006; accepted 26 April 2006
Abstract
Some platinum (IV) complexes [Pt(L)2Cl2] [where, L = 2-aminopyridine-N-thiohydrazide (L1), (2-aminopyridine-N-thio)-1,3-propanediamine
(L2), benzaldehyde-2-aminopyridine-N-thiohydrazone (L3) and salicylaldehyde-2-aminopyrtidine-N-thiohydrazone (L4)] have been synthesized.
The thiohydrazides, thiodiamine and thiohydrazones can exist as thione–thiol tautomer and coordinate as a bidentate N–S ligand. The ligands found
to act in monobasic bidentate fashion. Analytical data reveals that metal to ligand stoichiometry is 1:2. The complexes have been characterized by
elemental analysis, IR, mass, electronic and 1H NMR spectroscopic studies. In vitro antibacterial and cytotoxic study have also been carried out
for some complexes.
© 2006 Elsevier B.V. All rights reserved.
Keywords: Synthesis; Characterization; Spectral; Cytototoxic and Antibacterial
1. Introduction
the pharmacological properties and thus the effectiveness of the
drug. However, platinum (IV) complexes have enormous poten-
tial as anticancer agents in terms of both high activity and low
toxicity, but this potential has not been realized by the drugs
investigated to date, probably because they are reduced too read-
ily in the bloodstream. The potential advantages of platinum
(IV) complexes that remain in the higher oxidation state in the
bloodstream are that their lower reactivity would diminish loss
of active drugs and lower the incidence of unwanted side reac-
tions that lead to side effects [14].
Platinum complexes suitable for oral administration have
been known to be water-soluble, lipophilic, and robust enough
to survive the gastric environment. For the platinum (IV) com-
plexes, ligand substitution reactions are slow compared with
their platinum (II) analogues and Pt(IV) complexes may be
required to be reduced to the kinetically more labile and reactive
Pt(II) derivatives in vivo [14,15]. Nowadays attention is focused
on platinum (IV) complexes with bioactive ligands, because of
the lower toxicity of platinum (IV) and the possibility of oral
administration of some potent platinum (IV) compounds as well
as the fact that they can coordinate to DNA. In view of num-
ber of applications of the thiohydrazides and thiohydrazones
[16–18] and the well proven clinical utility the platinum–metal
Platinum (IV) complexes are widely applied in the treatment
of various types of cancer such as testicular, ovarian and blad-
der carcinomas [1–5]. Cisplatin is used in the treating head
and neck cancer, lung carcinoma, stomach carcinoma and so
on [6,7]. However, the clinical usefulness of cisplatin has been
frequently limited by its severe side effects such as nephrotoxic-
ity, nausea, ototoxicity, neurotoxicity and myelotoxicity [8–10],
development of acquired resistance low activity against breast
and colon cancer. Therefore, it is desirable to develop new plat-
inum based drugs with broader spectrum of activity, improved
clinical efficacy and reduced toxicity, better than cisplatin
[11].
The platinum (IV) complexes have revealed significantly
greater activity in human than that of cisplatin is particularly
disappointing in light of the report [12,13]. The high activity
was ascribed to high cellular uptake, but in vivo reduction alters
∗
Corresponding author. Tel.: +91 11 27666616; fax: +91 11 7256605.
E-mail addresses: ajaykmishra1@yahoo.com (A.K. Mishra),
narenderkumar kaushik@yahoo.co.in (N.K. Kaushik).
1386-1425/$ – see front matter © 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2006.04.038

A.K. Mishra et al. / Spectrochimica Acta Part A 66 (2007) 1042–1047
1043
complexes, we have prepared platinum (IV) complexes of the
thiohydrazides, thiodiamines and thiohydrazones in order to
characterize and screen them for antibacterial and cytotoxic
activity.
a yellowish-white crystalline precipitate of 2-aminopyridine
dithiocarbamate separated. It was filtered, washed with ice-cold
aqueous methanol. The product was then suspended in 10 mL
methanol and treated with freshly prepared potassium chloroac-
etate [(0.05 mol) {potassium chloroacetate was obtained by
dissolving 4.73 g chloroacetic acid in 3 mL ice-cold water and
mixing it in 5 mL aqueous solution of 2.8 g potassium hydrox-
ide}]. The temperature of the reaction mixture was kept at
about 40 ◦C for an hour and the contents were left overnight
at room temperature. After 24 h methanolic solution of 2.44 mL
(0.05 mol) hydrazine hydrate (density 1.026) was added to the
reaction mixture. The content was then heated on a water
bath for about 45 min when the desired product began to
separate out. It was cooled in ice for 24 h and filtered. 2-
Aminopyridine-N-thiohydrazide thus obtained was recrystal-
lized from methanol and dried under vacuum over CaCl2 at room
temperature.
2. Experimental
2.1. Chemicals and materials
All the reagents used were AR grade. The analysis of
CHNS/O contents of ligands and metal complexes were done
on Elementar Analysensysteme Gmbh Vario El-III. IR and far
IR were recorded on Perkin-Elmer spectrum 2000 FTIR spec-
trometer. Electronic spectra were recorded on Shimadzu UV–vis
spectrophotometer Model 1601. Conductance measurements
werecarriedoutonDigitalConductometerModelPT-827, India.
Model JEOL SX102/DA-600 (KV 10MA) was used for record-
ing mass spectra of the ligands. 1H NMR was recorded on
Brucker spectrospin 300 spectrometer.
The reactions taking place in the preparation are shown
below.
CHNS-analysis; found (calculated) %: C; 43.46 (42.86), H;
4.28 (4.77), N; 34.23 (33.33), S; (18.67) 19.0. Mass spectra
(CH3OH); m/z: 168.76.
2.2. Preparation of thiohydrazides
2.2.2. Preparation of
(2-aminopyridine-N-thio)-1,3-propanediamine (L2)
Preparation of 2-aminopyridine-N-thiohydrazides, (2-amin-
opyridine-N-thio)-1,3-propanediamine, benzaldehyde-2-ami-
nopyridine-N-thiohydrazone and salicylaldehyde-2-aminop-
yrtidine-N-thiohydrazone were prepared by modified [16–18]
literature method [19].
10.4 g (0.05 mol) 2-aminopyridine dithiocarbamate prepared
as earlier was suspended in 15 mL methanol and treated
with freshly prepared potassium chloroacetate [(0.05 mol)
{potassium chloroacetate was obtained by dissolving 4.73 g
chloroacetic acid in 3 mL ice-cold water and mixing it in 5 mL
aqueous solution of 2.8 g potassium hydroxide}]. The temper-
ature of the reaction mixture was kept at about 40 ◦C for an
hour and the contents were left overnight at room temper-
ature. After 24 h methanolic solution of 4.36 mL (0.05 mol)
1,3-propanediamine (density 0.85) was added to the reaction
mixture. The content was then heated on a water bath for about
45 min when the desired product began to separate out. It was
cooled in ice for 24 h and filtered. (2-aminopyridine-N-thio)-1,3-
propanediamine thus obtained was recrystallized from methanol
and dried under vacuum over CaCl2 at room temperature.
The reactions taking place in the preparation are shown
below.
2.2.1. Preparation of 2-aminopyridine-N-thiohydrazide
(L1)
In a three necked round bottle flask 4.71 g (0.05 mol) of 2-
aminopyridine dissolved in 20 mL methanol taken and chilled
it. To this, a chilled solution of 2.8 g (0.05 mol) potassium
hydroxide in 1 mL water and 10 mL methanol was mixed with
constant stirring. The mixed solution was treated with an ice-
cold solution of 3.02 mL (0.05 mol) carbon disulphide (den-
sity 1.26) in 3 mL methanol. The temperature of the reaction
mixture was maintained below 10 ◦C by keeping flask in a
freezing mixture of common salt and ice. During the process,

1044
A.K. Mishra et al. / Spectrochimica Acta Part A 66 (2007) 1042–1047
CHNS-analysis; found (calculated) %: C; 52.68 (51.40), H;
6.63 (6.67), N; 25.59 (26.67), S; (14.93) 15.20. Mass spectra
(CH3OH); m/z: 210.89.
2.4. Preparation of complexes
Preparation of thiohydrazide [Pt(L)2Cl2] complexes where
L = L1, L2, L3 and L4. The corresponding ligand L [where
L = L1 (0.084 g, 0.5 mmol), L2 (0.105 g, 0.5 mmol), L3 (0.128 g,
0.5 mmol) and L4 (0.141 g, 0.5 mmol)] in methanol was added
to aqueous solution of H2PtCl6 (0.103 g, 0.25 mmol). The solu-
tion was stirred for 4–5 h. The colour of solution changed yellow
to yellowish-orange. It was washed with double distilled water
several times and dried in desiccator over CaCl2 under vacuum.
2.3. Preparation of thiohydrazones
The thiohydrazones were prepared by refluxing the thiohy-
drazides with corresponding aldehydes or ketones in methanol.
2.3.1. Preparation of
benzaldehyde-2-aminopyridine-N-thiohydrazone (L3)
5.04 g (0.03 mol) of 2-aminopyridine-N-thiohydrazide and
3.05 mL (0.03 mol) of benzaldehyde (density 1.044) were
refluxedinmethanolfor3 h. Oncoolingyellowishmassobtained
was filtered and washed with cold methanol. It was recrystallized
from hot methanol.
2.5. In vitro antibacterial activity
Most of the compounds have been screened in vitro
against Streptomyces epidermidis. Various methods [20–23] are
CHNS-analysis; found (calculated) %: C; 61.17 (60.93), H;
4.73 (4.70), N; 20.99 (21.87), S; (11.86) 12.50. Mass spectra
(CH3OH); m/z: 256.73.
available for the evaluation of the antibacterial activity of dif-
ferent types of drugs. However, the most widely used method
[23] consists in determining the antibacterial activity of the drug
is to add it in known concentrations to the cultures of the test
organisms.
2.3.2. Preparation of
salicylaldehyde-2-aminopyridine-N-thiohydrazone (L4)
5.04 g (0.03 mol) of 2-aminopyridine-N-thiohydrazide and
3.15 mL (0.03 mol) of salicylaldehyde (density 1.164) were
refluxedinmethanolfor3 h. Oncoolingyellowishmassobtained
was filtered and washed with cold methanol. It was recrystallized
from hot methanol.
2.5.1. Disc diffusion assay
The disc diffusion assay was used to determine antibacte-
rial activity of the drug using Gram positive and Gram negative
strains of bacteria namely S. epidermidis. Base plates were
CHNS-analysis; found (calculated) %: C; 56.96 (57.35), H;
4.26 (4.41), N; 19.47 (20.59), S; (11.98) 11.76. Mass spectra
(CH3OH); m/z: 272.43.
prepared by pouring 10 mL of autoclaved Muller-Hinton agar
(Biolab) into sterile Petri dishes (9 cm) and allowing them to
settle. Molten autoclaved Muller-Hinton that had been kept at

A.K. Mishra et al. / Spectrochimica Acta Part A 66 (2007) 1042–1047
1045
Table 1
Elemental analysis
Complexes
% Found (calculated)
C
H
N
S
Cl
Metal
Pt(L1)2Cl2
Pt(L2)2Cl2
Pt(L3)2Cl2
Pt(L4)2Cl2
23.67 (23.92)
32.05 (31.48)
40.03 (40.10)
39.01 (38.52)
2.63 (2.66)
4.02 (4.08)
3.17 (3.08)
2.97 (2.96)
18.43 (18.60)
17.01 (16.33)
14.28 (14.39)
14.75 (14.83)
10.41 (10.63)
9.19 (9.33)
7.99 (8.22)
8.11 (7.90)
10.93 (11.79)
11.28 (10.35)
9.27 (9.13)
33.04 (32.39)
28.50 (28.43)
25.56 (25.06)
24.19 (24.07)
8.69 (8.77)
48 ◦C was inoculated with a broth culture (106 to 108 mL−1
)
diphenyltetrazolium bromide). MTT solutions 20 ␮L (5 mg/mL
dd H2O) along with 200 ␮L of fresh, complete media were
added to each well and plates were incubated for 4 h. Follow-
ing incubation, the medium was removed and the purple for-
mazan precipitate in each well was sterilized in 200 ␮L DMSO.
Absorbance was measured using Techman Magellan microplate
reader (molecular device) at 570 nm and the percentage (%)
cytotoxicity was calculated as:
of the test organism and then poured over the base plate. The
discs were air dried and placed on the top of the agar layer.
Four replicants of each drug tested (four disc per plate) with
a gentamycin disc (0.5 ␮g/disc) as a reference. The plates were
then incubated for 18 h at room temperature. Antibacterial activ-
ity is expressed as a ratio of the inhibition zone produced by
the drug to the inhibition zone produced by the gentamycin
standard.
O.D. in sample well
Cytotoxicity (%) = 1 −
× 100
O.D. in control well
2.5.2. Micro dilution antibacterial assay
FCS is the fetal calf serum, PBS is phosphate buffered saline
(FCS was obtained from Genetix, DMSO from cell culture
tested, MTT from SRL, and DMEM were purchased from
Sigma, USA).
The serial dilution technique described by using 96-well
micro plates to determine the minimum inhibitory concentra-
tion (MIC) of the drugs for antibacterial activity was used. Two
milliliter cultures of four bacterial strains of S. epidermidis was
prepared and placed in a water bath overnight at 37 ◦C. The
overnight cultures were diluted with sterile Muller-Hinton broth.
The drugs were resuspended to a concentration of 60 ␮g/disc
(in DMSO) with sterile distilled water in a 96-well micro plate.
A similar two-fold serial dilution of gentamycin (Sigma) was
used as positive control against each bacterium. One hundred
microliters of each bacterial culture was added to each well. The
plates were covered and incubated overnight at 37 ◦C. To indi-
cate bacterial growth p-iodonitrotetrazolium violet was added to
each well and the plates incubated at 37 ◦C for 30 min. Bacterial
growth in the wells were indicated by a red colour, whereas clear
wells indicated inhibition.
3. Results and discussion
3.1. Elemental analysis
Elemental analysis (Table 1) reveals the purity of the com-
plexes. All complexes are soluble in DMSO. The molar con-
ductance values of the isolated complexes measured in DMSO
are found to be less than 15 ꢀ−1 cm2 mol−1 suggesting their
non-electrolytic nature.
3.2. Electronic spectra
The electronic spectra (Table 2) of the thiohydrazides (L1),
thiodiamines (L2), thiohydrazones (L3 and L4) show spectral
2.6. In vitro cell growth inhibition assay (cytotoxicity test)
Cells were seeded in 96-well plates at a concentration of
0.1–1.0 × 104 cells/well in 200 ␮L of complete media and incu-
bated for 24 h at 37 ◦C in 5% CO2 atmosphere to allow for cell
adhesion. Stock solutions (4 mM) of the compounds made in
DMSO were filter sterilized, then diluted to 1 mM in incom-
plete media. The 1 mM solutions were further diluted to 500 ␮M
and 50 ␮M incomplete media for treatment against HeLa cell
lines, where 40–4 ␮L of compound solutions were added to
160–196 ␮L, respectively, of fresh medium in wells to give final
concentrations of 100–1 ␮M. All assays were performed in two
independent sets of quadruplicate tests. Control group contain-
ing no drug as well as equivalent amounts of DMSO was run in
each assay.
Table 2
Electronic spectra
Complexes
λmax (nm)
Log ε
270
312
398
3.98
2.87
2.21
Pt(L1)2Cl2
282
324
386
3.88
2.65
2.02
Pt(L2)2Cl2
Pt(L3)2Cl2
Pt(L4)2Cl2
277
330
393
3.59
2.87
2.45
280
322
386
3.89
3.57
2.78
Following 48 h of exposure of cells to drug, each well
was carefully rinsed with 200 ␮L PBS buffer. Cytotoxic-
ity was assessed using MTT (3-[4,5-dimethylthiazol-2yl]-2,5-

1046
A.K. Mishra et al. / Spectrochimica Acta Part A 66 (2007) 1042–1047
• L1—δ (ppm): 7.73–6.4 (m, 4H, Py-H), 9.16 (br s, 1Ha, –NH),
Table 3
IR spectra
3.43 (br s, 2Hb, –NH2).
• [Pt(L1)2Cl2]—δ (ppm): 8.93–7.86 (m, 8H, Py-H), 9.21 (br s,
Compounds ν(C N) ν(N–N) ν(C S) ν(M–N) ν(M–S) ν(M–Cl)
2Ha, –NH), 3.68 (br s, 4Hb, –NH2).
L1
–
–
–
1025
1028
1032
1016
1026
1018
1036
1028
876
767
880
785
890
745
888
767
–
469
–
462
–
481
–
471
–
385
–
376
–
378
–
382
–
265
–
270
–
305
–
310
• L2—δ (ppm): 7.7–6.6 (m, 4H, Py-H), 9.12 (br s, 1Ha, –NH),
3.3 (t, 4Hb, –CH2), 1.8 (m, 2Hc, –CH2), 3.67 (br s, 2Hd,
–NH2).
Pt(L1)2Cl2
L2
Pt(L2)2Cl2
L3
–
1633
1628
1614
1635
• [Pt(L2)2Cl2]—δ (ppm): 8.43–7.74 (m, 8H, Py-H), 9.17 (br s,
2Ha, –NH), 2.43 (t, 8Hb, –CH2), 1.9 (m, 4Hc, –CH2), 4.5 (br
s, 4Hd, –NH2).
Pt(L3)2Cl2
L4
Pt(L4)2Cl2
• L3—δ (ppm): 7.7–6.51 (m, 4H, Py-H), 9.6 (br s, 1Ha, –NH),
9.16 (br s, 1Hb, –NH), 8.23 (s, 1Hc, –CH), 7.3–6.4 (m, 5H,
–Ar–H).
*
*
bands because of ␲ → ␲ and n → ␲ transition. In UV spec-
tra of ligand L1 two bands at 230 nm (log ε = 3.35) and 281 nm
(log ε = 2.47). Two absorption bands are observed for ligand L2
at 239 nm (log ε = 3.75) and 285 nm (log ε = 2.36). Thiohydra-
zones (L3 and L4) show three bands, ligand L3 absorbs at 227 nm
(log ε = 3.99), 265 nm (log ε = 3.37) and 302 nm (log ε = 2.25).
LigandL4 absorbsat238 nm(log ε = 4.02), 290 nm(log ε = 3.45)
and 303 nm (log ε = 2.55). On complexation these bands are
shifted. Strong charge transfer transitions may interfere and pre-
vent the observation of all the expected bands [24,25]. Strong
bands ∼340 nm is assignable to a combination of metal ligand
charge transfer (M → LCT) and d–d band. The very intense band
∼390 is assignable to combination of sulphur → metal charge
transfer (L␲ → MCT) and d–d bands.
• [Pt(L3)2Cl2]—δ (ppm): 8.43–7.41 (m, 8H, Py-H), 9.43 (br s,
2Ha, –NH), 9.19 (br s, 2Hb, –NH), 8.23 (s, 1Hc, –CH), 7.7–6.7
(m, 10H, –Ar–H).
• L4—δ (ppm): 7.21–6.42 (m, 4H, Py-H), 10.42 (br s, 1Ha,
–NH), 9.1 (br s, 1Hb, –NH), 8.3 (s, 1Hc, –CH), 7.4–6.26 (m,
5H, –Ar–H), 11.3 (br s, 1Hd, –OH).
• [Pt(L4)2Cl2]—δ (ppm): 8.41–7.6 (m, 8H, Py-H), 10.21 (br s,
2Ha, –NH), 9.17 (br s, 2Hb, –NH), 8.15 (s, 1Hc, –CH), 7.9–6.5
(m, 10H, –Ar–H), 11.26 (br s, 2Hd, –OH).
The 1H NMR spectrum of thiohydrazides, thiodiamines and
thiohydrazones [30,31] shows two signals at δ ∼9.0–10.3 and δ
∼4.0 ppm, due to the presence of NH protons, which are lost on
D2O exchange. This is observable in the complexes also suggest-
ing that hydrogen bonding to the solvent occurs in the complexes
as well as free ligands. The resonance assigned to aldehyde –CH
is generally shifted upfield, indicating coordination of azome-
thine nitrogen [32].
3.3. Infrared spectra
The IR spectra (Table 3) of the thiohydrazides, thiodiamines
and thiohydrazones contain groups –NH–C S as a potential
bond forming site. The IR bands are shifted on complex forma-
tion due to increased double bond character of C N group on
complexation. The band due to ν(C S) 750–900 cm−1 is a major
contributor and ν(C N) as minor. This is shifted to lower fre-
quency on complexation indication the coordination to metal ion
3.5. Antibacterial study
In the current study (Table 4), some synthesized com-
plexes were tested against pathogenic bacterial strains such as
Staphylococcus epidermidis (S. epidermidis) using the disc dif-
fusion method. Gentamycin was used as reference drug for
bacteria.
is through thioamide sulphur C S. This shift is ∼80–140 cm−1
,
if coordination is through thiol sulphur [26] and 30–40 cm−1, if
coordination is through the thione sulphur [27]. In all the com-
plexes the thiohydrazide, thiodiamine and thiohydrazone ligand,
no band for ν(S–H) in the region 2600–2800 cm−1 is observed
which shows the absence of any thiol (–SH) tautomer in the solid
state. However, in solution and in the presence of certain metal
ion, the ligands may exist in equilibrium with the tautomeric
thiol form.
3.6. Cytototoxic study
In the present studies (Table 5), the cytotoxic property of
one metal complex has been determined. The study was used to
test the growth inhibition assay by MTT assay. Data expressed
in terms of percentage (%) cytotoxicity. The metal complexes
caused ∼50% inhibition. The results of the antitumour activity
of the metal complexes suggested that the complexes are an
effective inhibitor at moderate concentrations. The importance
In all the Pt(IV) complexes the metal nitrogen vibration,
ν(M–N) are assigned to the new bands [28] in the far IR
between 460 and 490 cm−1, while in the region between 350 and
390 cm−1 gives metal–sulphur, ν(M–S) band stretching [29].
The band at ∼330–270 cm−1 is assigned due to ν(Pt–Cl) stretch-
ing vibrations.
Table 4
Antibacterial study
Serial no.
Complexes
Zone of inhibition (mm),
S. epidermidis
3.4. NMR spectra
1
2
Pt(L1)2Cl2
Pt(L2)2Cl2
8
8
1H NMR spectra of ligands and complexes were recorded in
d6-DMSO taking TMS as internal standards.

A.K. Mishra et al. / Spectrochimica Acta Part A 66 (2007) 1042–1047
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Table 5
Cytototoxic study
[5] R.F. Ozols, R.C. Young, Semin. Oncol. 11 (1984) 251.
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Serial no.
1
Complexes
Pt(L1)2Cl2
Concentrations (␮g/mL)
100
10
1
45.5
13.6
9.1
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Hillen, G.J. Hogendoorn, H. Scheerder, V. van der, Cancer Chemother.
Pharmacol. 15 (1985) 86.
of such work lies the possibility that the new complexes might
more efficacious drug against tumours for which a thorough
investigation regarding the structure activity of the complexes
and their stability is required in order to understand the variation
in their biological effects, which could be helpful in designing
more potent antitumour agents for therapeutic use.
[9] D.D. Von Hoff, R. Schilsky, C.M. Reichert, R.L. Reddick, M. Rozencweig,
R.C. Young, F.M. Muggia, Cancer Treat. Rep. 63 (1979) 1527.
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4. Conclusion
All the complexes are found to be diamagnetic, so the
Pt(IV) complexes must be octahedral. Pt(IV) is d6 system
1
3
and four bands are expected corresponding to A1g → T1g,
1A1g → T2g, A1g → T1g and A1g → T2g transitions. The
shift towards lower frequency on complexation, indicates the
coordination to metal ion is through thioamide sulphur. The
antibacterial study of the complexes shows significant activity.
The bacterial strains with the zone of inhibition were observed,
8 mm. One complex was tested for the cytotoxic activity. The
complex was tested on primary adenocarcinoma (colour). The
complex showed good activity at 100 and 1 ␮M solutions. On
dilution activity decreases, which show that, the complex is an
effective inhibitor at moderate concentrations. On the basis of
these spectroscopic studies the probable structure of the com-
plexes is:
3
1
1
1
1
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