Spectral and thermal studies with anti-fungal aspects of some organotin(IV) complexes with nitrogen and sulphur donor ligands derived from 2-phenylethylamine

Article abstract of DOI:10.1016/j.saa.2008.01.015

Some complexes of 2-phenylethyl dithiocarbamate, thiohydrazides and thiodiamines with dibenzyltin(IV) chloride, tribenzyltin(IV) chloride and di(para-chlorobenzyl)tin(IV) dichloride have been synthesized and investigated in 1:2 and 1:1 molar ratio. The di

Full text of DOI:10.1016/j.saa.2008.01.015

Available online at www.sciencedirect.com
Spectrochimica Acta Part A 71 (2008) 669–675
Spectral and thermal studies with anti-fungal aspects of some organotin(IV)
complexes with nitrogen and sulphur donor ligands derived from
2-phenylethylamine
Rajeev Singh, N.K. Kaushik∗
Organometallic Research Laboratory, Department of Chemistry, University of Delhi, Delhi-110007, India
Received 19 April 2007; received in revised form 5 January 2008; accepted 12 January 2008
Abstract
Some complexes of 2-phenylethyl dithiocarbamate, thiohydrazides and thiodiamines with dibenzyltin(IV) chloride, tribenzyltin(IV) chloride
and di(para-chlorobenzyl)tin(IV) dichloride have been synthesized and investigated in 1:2 and 1:1 molar ratio. The dithiocarbamate ligand act as
monoanionic bidentate and thiohydrazide, thiodiamines act as neutral bidentate ligand. The synthesized complexes have been characterized by
elemental analysis and molecular weight determination studies and their bonding pattern suggested on the basis of electronic, infrared, 1H and 13
C
NMR spectroscopy. Using thermogravimetric (TG) and differential thermal analysis (DTA) various thermodynamic and kinetic parameters viz.
reaction order (n), apparent activation energy (Ea), apparent activation entropy (S#) and heat of reaction (ꢀH) have been calculated and correlated
with the structural aspects for solid-state decomposition of complexes. The ligands and their tin complexes have also been screened for their
fungitoxicity activity against Rhizoctonia solanii and Sclerotium rolfsii and their ED50 values calculated.
© 2008 Elsevier B.V. All rights reserved.
Keywords: Organotin(IV) complexes; Synthesis; Spectral; Phenomenological; Kinetic; Anti-fungal (ED50
)
1. Introduction
are registered in all the EU member states and many other coun-
tries [11]. The thiohydrazides are the hydrazine derivatives of
dithioacid (RCS2−H+) and thiodiamines are the diamine deriva-
tives of dithioacid (RCS2−H+). The work has been reported by
many workers [7,8,11–17] by synthesizing and characterizing
thesetypesofligandsandtheircomplexesusingdifferentmetals.
Inthispaperwereportonthesynthesis, spectralcharacterization,
thermal decomposition pattern and the fungitoxicity aspects of
the reaction of organotin(IV) chloride with the ligands proposed,
derived from 2-phenylethylamine. The structures of the ligands
are shown in Figs. 1 and 2.
Organotin compounds have a wide range of applications and
they are amongst the most widely used organometallic chemi-
cals. The use of organotins in industry has risen dramatically
as a result of their wide range of technical applications and
their favorable environmental and toxological properties [1]. At
present, the industrial uses of non-toxic organotin compounds
account for almost two-third of the total world consumption,
though the other major use for these derivatives as anticancer
[2], antifouling [3,4] and bactericidal [5,6], fungicidal [7–9] and
antiviral agents [10].
The dithiocarbamates (R2NCS2−) are the half-amides of
dithiocarbonic acid. These are the sulphur analogs of carbamates
(R2NCO2−). The strong metal binding properties of dithiocar-
bamates are directly related to their possession of two donor
sulphur atoms. DTCs are the main group of fungicides used to
control approximately 400 pathogens of more than 70 crops and
2. Experimental
2.1. Physical measurements
All reagents used were AR grades and the solvents were
purified by standard method and dried before use. The elemen-
tal analysis was carried out on an Elementar Analysensysteme
GmbH Varion EL III, Germany. Tin was estimated gravimet-
rically as SnO2 and chlorine was estimated volumetrically by
Volhard’s method. The Rast Camphor Method was used to carry
∗
Corresponding author. Tel.: +91 931 122 5501; fax: +91 112 776 2780.
E-mail addresses: raajeevssiingh@yahoo.com (R. Singh),
narenderkumar kaushik@yahoo.co.in (N.K. Kaushik).
1386-1425/$ – see front matter © 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2008.01.015

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2.3.1. Preparation of 2-phenylethyl dithiocarbamate (L1)
The dithiocarbamate was prepared by the method described
by Gilman and Blatt [20] with some modifications. Phenylethy-
lamine (25.37 ml, 0.2 mol) (density 0.960) was dissolved in
ethanol and to it KOH (11.2 g, 0.2 mol) in minimum ethanol
was added. Carbon disulphide (12.06 ml, 0.2 mol) (density 1.26)
was then added to the mixture, the temperature being kept below
10 ◦C. An off-white crystalline precipitate of the potassium salt
of 2-phenylethyl dithiocarbamate separated, which was further
recrystallized from ethanol and dried in vacuum dessicator over
CaCl2.
Fig. 1. Structure of dithiocarbamate ligand (L1).
out the molecular weight determinations. The electronic spectra
were recorded on a Varian Cary 100 UV–vis spectrophotometer.
IR and far IR spectra were recorded on KBr and polyethylene
discs respectively using a PerkinElmer Spectrum 2000 FTIR
1
spectrometer and H, 13C NMR spectra were recorded on a
Bruker Spectrospin Advance 300 spectrometer. The TG/DTA
were recorded on a Thermoflex PTC-10A Rigaku Corporation,
Japan in static air at heating rate 5◦ min−1. The Pt crucible was
used with alumina as the reference material.
Anal. Calcd. for L1 (%): C, 45.92; H, 4.28; N, 5.95; Found: C,
44.92; H, 4.78; N, 5.55.
2.2. Fungitoxicity testing
2.3.2. Preparation of N-thiohydrazide (L2) and
N-thiodiamine (L3 and L4)
The in vitro antifungal activities of the ligands and their
corresponding complexes were tested by poisoned food tech-
nique using potato–dextrose–agar (PDA) medium at 500 ppm,
250 ppm and 125 ppm. Rhizoctonia solanii Kuhn and Sclerotium
rolfsii Saccardo were used as test organisms. A 5-mm thick
disk of fungus (spores and mycelium) cut from earlier subcul-
tured Petridish was put in the centre of the solidified medium
in the test Petriplates and lids replaced. Both treated and con-
trol Petriplates were kept in BOD incubator at 25 1 ◦C for
4–6 days. The mycellial growth of fungus (cm) in both treated
(T) and control (C) Petriplates were measured diametrically in
three different directions. Two replicates were taken for each
treatment. From the mean growth of above reading percent-
age inhibition of growth (I) was calculated by using formula:
I(%) = {[C − T]/C} × 100. From the mean growth percentage
inhibition (%I), the ED50 values were calculated by means of a
Basic LD50 programme Version 1.1 [18].
The ligand 2-phenylethyl N-thiohydrazide have been syn-
thesized by the method of Kazakova et al. [21–23] with some
modifications. The aqueous solution of dithiocarbamate was
treated with freshly prepared potassium chloroacetate (0.2 mol).
The temperature of the reaction mixture was increased to and
maintained below 40 ◦C for 1 h. The mixture was then left
for 24 h at room temperature. Then a methanolic solution of
hydrazine hydrate (9.72 ml, 0.2 mol) was added and the reac-
tion mixture heated on a water bath for an hour, at which the
desired product separated. It was cooled in ice for 24 h, and
then filtered. The thiohydrazide so obtained was recrystallized
and dried. Similar procedure was followed for N-thiodiamines
of 1,3-diaminopropane (L3) and 1,2-diaminoethane (L4). They
were recrystallized from water and dried over CaCl2.
Anal. Calcd. for L2 (%): 55.38; H, 6.66; N, 21.53; Found: C,
54.37; H, 6.65; N, 20.44.
2.3. Preparation of organotin and ligands
Anal. Calcd. for L3 (%): C, 60.75; H, 8.01; N, 17.73; Found:
C, 61.30; H, 7.82; N, 17.77.
Dibenzyltin(IV) dichloride (C6H5CH2)2SnCl2; di(para-
chlorobenzyl)tin(IV) dichloride (p-ClC6H4CH2)2SnCl2 and
tribenzyltin(IV) chloride (C6H5CH2)3SnCl were synthesized by
the method given by Sisido et al. [19].
Anal. Calcd. for L4 (%): C, 59.19; H, 7.65; N, 18.83; Found:
C, 59.5; H, 6.32; N, 18.73.

R. Singh, N.K. Kaushik / Spectrochimica Acta Part A 71 (2008) 669–675
671
Fig. 2. Structure of N-thiohydrazide and N-thiodiamine ligands. Rꢀ: L2,
–NHNH2; L3, –NH(CH2)3NH2; L4, –NH(CH2)2NH2.
2.4. Preparation of complexes
2.4.1. Preparation of dithiocarbamate complexes
A solution of potassium 2-phenylethyl dithiocarbamate [L1,
4.70 g (0.02 mol)] in 25 ml THF was added slowly to a solution
of R2SnCl2 (0.01 mol) or R3SnCl (0.02 mol) in 25 ml THF. The
contents were stirred for ∼9 h on a water bath at 60 ◦C. The
solution was reduced in concentration to one-fourth of original
volume under vacuum and the complex so obtained was dried
in a vacuum dessicator over anhydrous CaCl2.
2.4.2. Preparation of N-thiohydrazide and N-thiodiamines
complexes
A solution of ligand [L2, 3.90 g; L3, 4.74 g; L4, 4.46 g
(0.02 mol)] in 25 ml of dioxane was added slowly with con-
tinuous stirring to corresponding organotin chloride R2SnCl2
or R3SnCl (0.02 mol) in 25 ml of dioxane. The mixture so
obtained was refluxed for an hour and stirred for additional
∼4 h and then the solution was reduced in concentration to
one-fourth of its original volume under vacuum. The complex
so obtained was recrystallized in acetone and finally washed
with petroleum ether and dried in a dessicator over CaCl2. For
the(C6H4CH2)2Sn(L3)Cl2 complex, 1:7distilledwater–acetone
mixture was used as a solvent medium.
3. Results and discussions
The complexes synthesized were found to be pure and soluble
in acetone, chloroform and dimethylsulphoxide solvents. All the
complexes were colored and showed sharp melting point. The
elemental analysis is given for the complexes in Table 1.
3.1. Electronic spectra
In the UV–vis spectra, the dithiocarbamate ligand showed
two absorption bands due to the chromophore group (NCS2).
Band I in the 260 nm region is attributed to ␲–␲* transition
of
groups. Band II in the ∼290 nm region is due
to ␲–␲* electronic transition involving lone pair of electrons
locatedonthesulphuratom, respectively. Oncomplexationthese
bands shifted to lower wavelength, showing the involvement
of NCS2 group in all the complexes. In case of thiohydrazide
and thiodiamines due to chromophore region, absorption bands
are assigned as ␲–␲* transition. These bands are at ∼262 nm
corresponding to free ligands which shift to lower wavelength
∼261 nmindicatingtheinvolvementofC Sgrouponcomplexa-
tion. One additional band also appears in the complexes because
of metal–ligand charge transfer.

672
R. Singh, N.K. Kaushik / Spectrochimica Acta Part A 71 (2008) 669–675
Table 2
in comparison to the free ligands is due to coordination of the
ligand to metal ion.
1H and 13C NMR spectral data for dithiocarbamate complexes
Complexes
1H
NH
13C
C
In thiohydrazides and thiodiamines (Table 3), the terminal
NH2 of the thiohydrazide ligand experiences a downfield shift
indicating coordination through the terminal nitrogen or NH2
group to the tin metal. The aromatic proton signals, which appear
in the form of a complex multiplet at δ 6.89–6.78 ppm, shifts to
δ 6.92–6.79 ppm due to deshielding on complexation. On com-
plexation, additional peaks were also observed in the region
δ 7.20–7.11 ppm (ArH) and δ ∼2.91 ppm corresponding to the
Sn CH2 groups present in the complexes. On comparison
withliteraturereports[12,14]ofsimilarsynthesizedcompounds,
significant changes in the δ (ppm) value support more stable
coordination on complexation.
Sn CH2
S
Sn CH2
L1
3.61
3.81
3.83
3.89
–
179.9
181.5
186.6
183.5
–
(C6H5CH2)2Sn(L1)2
(p-ClC6H4CH2)2Sn(L1)2
(C6H5CH2)3Sn(L1)
2.89
2.93
2.91
18.19
24.66
17.34
3.2. Infrared spectra
The IR spectra of dithiocarbamate complexes show a strong
band in the 1491–1505 cm−1 region, which is attributed to the
␯(C N) stretching frequency. In the free ligands the ␯(C N)
frequency occurs at ∼1452 cm−1. The occurrence of this fre-
quency at lower energy in the free ligands as compared to the
metal complexes is expected since on complexation there is an
increase in electron density on the sulphur atoms due to back
donation of electrons from metal d-orbitals to the vacant anti-
bonding sulphur orbitals. The band at 950 cm−1 and 933 cm−1 is
assigned to ␯(C S) which on complexation shows a strong band
at 1007 cm−1 indicating that all the dithiocarbamate ligands are
of bidentate nature and symmetrically bonded.
Comparativelyinthiohydrazideandthiodiaminescomplexes,
the ꢁNH stretching vibration at ∼3210 cm−1 of terminal ꢁNH2
group shifted to lower frequency, indicating the coordination of
NH2 group to the metal atom. The band at 933 cm−1 assignable
to a ␯(C S) shifts to lower frequency ∼903 cm−1. A peak at
1207 cm−1 is observed for ␯(C N). Significant changes in lig-
and bands upon complexation indicate coordination through the
terminal nitrogen and thiocarbonyl sulphur. Besides this, far
IR spectra of the metal complexes showed several new bands,
which are ␯(Sn S) [24,25] at 352 cm−1, ␯(Sn N) [25,26] at
696 cm−1, ␯(Sn Cl) [24,25] at 375 cm−1, thus lending support
to the proposed coordination in the complexes.
3.4. 13C NMR spectra
13CNMR data have been recorded for all the ligands and their
corresponding tin complexes (Tables 2 and 3). In all the com-
plexes, the thione carbon suffer upfield shifts in the complexes
thereby supporting a change in the ꢁC S bond order indicating
that the coordination of ligands is through sulphur to the metal
ions.
On the basis of elemental analysis, spectral evidence and
thermal data; the following structures representing coordi-
nation have been proposed for the complexes synthesized
(Figs. 3 and 4).
3.5. Thermal studies
3.5.1. Phenomenological aspects
The phenomenological data for every step, determined from
the TG curves are presented in Table 4.
(C6H5CH2)2Sn(L1)2 complex. The TG curve (Fig. 5, curve
A) shows that the complex starts decomposing at 380 K and
continues to decompose till 566 K, this step corresponds to
3.3. 1H NMR spectra
The proton magnetic resonance spectra of the ligands and
their corresponding 1:2 and 1:1 tin complexes were recorded in
CDCl3 and shown in Tables 2 and 3. The results were compared
with, those of the free ligands. A number of signals have been
observed which on complexation shifts from their original posi-
tion. A downfield shift in the resonance signals of the complexes
Table 3
1H and 13C NMR spectral data for thiohydrazide and thiodiamine complexes
Complexes
1H
NH2
13C
C
Sn CH2
S
Sn CH2
L2
3.52
3.89
3.65
3.77
3.69
3.76
–
2.91
–
2.91
–
2.96
178.33
181.45
180.09
188.30
180.09
182.33
–
(C6H5CH2)2Sn(L2)Cl2
19.43
–
20.44
–
L3
(C6H5CH2)2Sn(L3)Cl2
L4
(C6H5CH2)2Sn(L4)Cl2
21.00
Fig. 3. Dithiocarbamate complexes.

R. Singh, N.K. Kaushik / Spectrochimica Acta Part A 71 (2008) 669–675
673
Fig. 6. DTA curves for dithiocarbamate complexes: (A) (C6H5CH2)2Sn(L1)2,
(B) (p-ClC6H4CH2)2Sn(L1)2, (C) (C6H5CH2)3Sn(L1), (D) (C6H5CH2)
2Sn(L2)Cl2, (E) (C6H5CH2)2Sn(L3)Cl2 and (F) (C6H5CH2)3 Sn(L4)Cl2.
Fig. 4. N-Thiodiamine complexes.
the loss of the two benzyl groups. The expected and observed
mass losses are 26.27% and 25.25% respectively. The final step
corresponding to the decomposition of organic part L1 and sub-
sequent conversion of Sn to SnO2 lies in the temperature range
566–890 K. The total expected and observed mass losses, after
the complete formation of SnO2 are 78.24% and 77.39% respec-
tively. In the DTA profile (Fig. 6, curve A) step I is shown as an
exothermic peak Tmax = 478 K and the final step is marked by an
endothermic peak with Tmax = 777 K. The heat of reaction (ꢀH)
for step I is 19.00 kJ g−1 and for the step II it is 62.36 kJ g−1
.
(C6H5CH2)3Sn(L1) complex. Step I of thermal degradation,
which initiated at 410 K and continued up to 559 K corresponds
to the loss of all the three benzyl groups (Fig. 5, curve C). The
expected and observed mass losses were 46.45% and 45.44%
respectively. After the completion of the final step, which cor-
responded to the decomposition of the organic part L1 and the
formation of SnO2, the total expected and observed mass losses
were 73.83% and 74.35%, respectively. This step lies in the tem-
peraturerange559–930 K. TheTGcurveisshown in Fig. 1curve
C. The DTA profile (Fig. 6, curve C) showed two thermal effects.
Fig. 5. TG curves for dithiocarbamate complexes: (A) (C6H5CH2)2Sn(L1)2,
(B) (p-ClC6H4CH2)2Sn(L1)2, (C) (C6H5CH2)3Sn(L1), (D) (C6H5CH2)
2Sn(L2)Cl2, (E) (C6H5CH2)2Sn(L3)Cl2 and (F) (C6H5CH2)3Sn(L4)Cl2.
Table 4
Phenomenological data for the thermal decomposition of the complexes
Complexes
Step no.
TG plateaux (K)
Mass loss observed (calc.) %
Nature of product
I
II
380–566
566–890
25.25 (26.27)
77.39 (78.24)
Loss of two benzyl groups and chlorine atom
Formation of SnO2
(C6H5CH2)2Sn(L1)2
(p-
I
II
389–610
610–920
31.50 (32.90)
79.8 (80.22)
Loss of two p-chlorobenzyl groups and two chlorine atoms
Formation of SnO2
ClC6H4CH2)2Sn(L1)2
I
II
410–559
559–930
45.44 (46.45)
73.83 (74.35)
Loss of three benzyl groups and chlorine atom
Formation of SnO2
(C6H5CH2)3Sn(L1)
I
II
423–690
690–1010
43.29 (44.64)
72.91 (73.40)
Loss of two benzyl groups and chlorine atom
Formation of SnO2
(C6H5CH2)2Sn(L2)Cl2
(C6H5CH2)2Sn(L3)Cl2
(C6H5CH2)2Sn(L4)Cl2
I
II
344–596
596–999
40.24 (41.62)
74.34 (75.91)
Loss of two benzyl groups and chlorine atom
Formation of SnO2
I
II
375–533
533–863
41.55 (42.47)
73.25 (74.60)
Loss of two benzyl groups and chlorine atom
Formation of SnO2

674
R. Singh, N.K. Kaushik / Spectrochimica Acta Part A 71 (2008) 669–675
Table 5
Kinetic parameters for the thermal decomposition of the complexes
Complexes
Step no.
TG
DTA
n
Ea (kJ mol−1
)
S (J K−1 mol−1
)
Thermal effect
Tmax (K)
ꢀH (kJ g−1
)
I
II
1
1
34.60
55.63
4.15
3.57
Exo
Endo
478
777
19.00
62.36
(C6H5CH2)2Sn(L1)2
(p-
I
II
1
1
33.63
60.76
2.50
4.16
Exo
Endo
560
792
14.23
70.29
ClC6H4CH2)2Sn(L1)2
I
II
1
1
39.68
49.17
4.63
2.80
Exo
Endo
515
756
9.64
71.56
(C6H5CH2)3Sn(L1)
I
II
1
1
34.40
71.14
1.73
4.30
Exo
Exo
630
901
14.33
48.63
(C6H5CH2)2Sn(L2)Cl2
(C6H5CH2)2Sn(L3)Cl2
(C6H5CH2)2Sn(L4)Cl2
I
II
1
1
27.45
50.67
2.12
1.65
Exo
Exo
492
892
24.63
47.48
I
II
1
1
41.25
45.51
5.99
2.29
Exo
Exo
471
750
9.81
51.63
The exothermic peak with Tmax at 515 K (ꢀH = 9.64 kJ g−1) cor-
responded to step I and an endothermic peak with Tmax at 756 K
(ꢀH = 71.56 kJ g−1) corresponded to the final step.
is a reference temperature, T − Tm, Tm is the peak temperature.
From the TG curves, the order of reaction (n), activation energy
(Ea) and entropy of activation (S#) of the thermal decomposition
reaction have been elucidated. The values of the heat of reaction
ꢀH, microvolts, were obtained directly from the computer fitted
to the thermoanalyser; it was converted to kJ g−1. The various
kinetic parameters calculated are given in Table 5.
(C6H5CH2)2Sn(L2)Cl2 complex. The TG curve (Fig. 5, curve
D) for this complex shows that almost 43.29% mass loss occurs
up to 690 K. The initial thermal decomposition step is over the
range 423–690 K. At this step there is loss of two benzyl groups
and chlorine atoms. The subsequent step at 1010 K shows a mass
loss of 72.90%; tin oxide (SnO2) is the end product. The DTA
curve (Fig. 6, curve D) show an exothermic peak at Tmax = 630 K
(ꢀH = 14.33 kJ g−1), for step I. An exothermic peak at 901 K
(ꢀH = 48.63 kJ g−1) corresponds to complete decomposition of
the complex.
3.5.3. Discussions
The TG and DTA curves are shown in Figs. 5 and 6, respec-
tively. The order of reaction for the thermal decomposition
of the above complexes was one. The decomposition of the
complexes was observed to be a two-step process, step 1 cor-
responding to the loss of all the benzyl groups (and chlorine
atom too in case of di(p-chlorobenzyltin(IV) dichloride). Step
II corresponded to the decomposition of the organic part, L
and ultimately, formation of SnO2. The DTA profile of each
complex showed the corresponding exothermic or endother-
mic peak. Further it was observed from the above data, that
the Sn R bond (where R = benzyl/p-chlorobenzyl) and Sn Cl
bond is weaker than Sn L (L = ligand) bond so these bonds
cleave before Sn L bond and hence, the activation energy
(Ea) value for step I is lower than step II because of greater
steric hindrance initially in the complexes. The energy of
3.5.2. Kinetic aspects
The kinetics of thermal decomposition of these complexes
has been measured under dynamic temperature conditions. Eval-
uation of kinetic parameters has been performed by means of
the Horowitz–Metzger method [26] assuming a rate law of the
type dx/dt = K(1 − α)n and an Arrhenius equation of the type
K = Z e−E/RT to be valid, where α represents the fraction trans-
formed, n the order of reaction, K the rate constant and E
is the activation energy; the graph for log(−ln(1 − α)) versus
1/T × 103 gave straight lines with slope Eθ/2.303Tm2 , where θ
Table 6
Anti-fungal screening data of the ligands and their tin complexes. (Inhibition %) (Conc. 125, 250, 500 ppm)
Compound
Rhizoctonia solanii
Sclerotium rolfsii
125
250
500
ED50
125
250
500
ED50
L1
28.32
52.66
43.23
37.91
43.33
25.25
39.36
55.70
43.2
54.64
68.86
58.44
57.18
63.20
43.62
55.65
63.56
60.60
62.31
73.31
68.21
66.66
83.40
78.52
73.65
79.26
77.32
54.82
19.76
35.09
42.62
31.76
51.26
39.38
21.21
33.11
46.14
45.23
42.38
29.33
47.51
36.82
41.36
46.68
48.72
59.36
54.66
55.55
64.86
62.99
43.28
61.14
59.15
57.88
64.18
68.29
75.45
78.82
83.98
68.92
78.36
65.55
75.12
30.83
35.40
35.60
39.48
29.10
54.34
33.15
31.17
28.86
(C6H5CH2)3Sn(L1)Cl
(p-ClC6H4CH2)2Sn(L1)Cl2
L2
(C6H5CH2)2Sn(L2)Cl2
L3
(C6H5CH2)2Sn(L3)Cl2
L4
(C6H5CH2)2Sn(L4)Cl2

R. Singh, N.K. Kaushik / Spectrochimica Acta Part A 71 (2008) 669–675
675
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