Synthesis, spectroscopic characterization, X-ray structure and biological screenings of organotin(IV) 3-[(3,5-dichlorophenylamido)]propanoates

Article abstract of DOI:10.1016/j.ica.2013.01.025

Six new organotin(IV) complexes with general formula R₃SnL/ R₂SnL₂ where R = CH₃ (1, 4), n-C ₄H₉ (2, 5), C₆H₅ (3) or C ₈H₁₇ (6) and L = 3-[(3,5-d

Full text of DOI:10.1016/j.ica.2013.01.025

Inorganica Chimica Acta 400 (2013) 159–168
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Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Synthesis, spectroscopic characterization, X-ray structure and biological
screenings of organotin(IV) 3-[(3,5-dichlorophenylamido)]propanoates
a
Farooq Ali Shah a, Muhammad Sirajuddin a, Saqib Ali a, , Syed Mustansar Abbas ,
⇑
Muhammad Nawaz Tahir b, Corrado Rizzoli c
a Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan
b Department of Physics, University of Sargodha, Sargodha 40100, Pakistan
c Department of General and Inorganic Chemistry, Analytical Chemistry, Physical Chemistry, University of Parma, Viale G. P. Usberti 17/A, I-43100 Parma, Italy
a r t i c l e i n f o
a b s t r a c t
Article history:
Six new organotin(IV) complexes with general formula R3SnL/R2SnL2 where R = CH3 (1, 4), n-C4H9 (2, 5),
C6H5 (3) or C8H17 (6) and L = 3-[(3,5-dichlorophenylamido)]propanoic acid were synthesized and struc-
turally characterized by elemental analyses, FT-IR, NMR (1H and 13C) spectral studies, and mass spec-
trometry. Spectroscopic results suggest that the ligand coordinate through oxygen atom of the
carboxylate groups. Crystal structure of complex (2) exhibits distorted trigonal-bipyrimidal geometry
around the tin atom while that of complex (3) exhibits tetrahedral geometry around the tin atom. Com-
plexes (1–6) were screened for their antifungal and antibacterial studies and the results showed that the
triorganotin(IV) complexes have higher activity against these microbes than the diorganotin(IV) com-
plexes. The complexes bind to DNA via electrostatic interaction of Sn(IV)+ moiety with the negatively
charged oxygen of phosphate group of DNA resulting in hyperchromism.
Received 16 November 2012
Received in revised form 24 January 2013
Accepted 25 January 2013
Available online 13 February 2013
Keywords:
Organotin(IV) complex
Crystal structure
DNA interaction
Antimicrobial activity
Ó 2013 Elsevier B.V. All rights reserved.
1. Introduction
tion number of central tin atom which results in variety of coordi-
nation geometries like dimeric, tetrameric, oligomeric ladder,
Organotin(IV) compounds are known for their profound effect
on daily life especially for their potential biological applications
and their versatile molecular structure. The wide range biological
applications of organotin(IV) complexes encourages the scientists
to design tin based drugs having good activity and low toxicity
for cancer chemotherapy due to their apoptotic (process of pro-
grammed cell death that may occur in multinuclear organisms)
inducing character [1–3].
Organotin(IV) complexes bind to phosphate group of DNA in
tumor cell and damage it. Thus the antitumor activity of the
compound retards the replication and synthesis of new DNA
[4]. Biological activity of organotin(IV) complexes is dependent
on the nature and number of organic groups R directly attached
to tin atom. However, the role of the ligand, for the transporta-
tion of organotin(IV) moiety to the target area, where the
organotin(IV) species perform its biocidal activity, cannot be ig-
nored [5–8].
cyclic, drums structure and polymers etc., [9–13]. Thus, the central
tin is saturated and has less probability of interaction with biolog-
ical systems. These evidences conclude the role of ligand in activity
of the complexes. Organotin(IV) complexes with different struc-
tural diversity are known to have different biological activities,
medicinal use, wood preservatives and pesticides. It is generally be-
lieved that the steric and electronic interaction decide the stereo-
chemistry of complex and geometry around central tin atom [14].
In the recent study we have synthesized six new organotin(IV)
complexes of the ligand L = 3-[(3,5-dichlorophenylamido)]propa-
noic acid with tri- and diorganotin(IV) compounds. The synthe-
sized ligand and complexes were characterized by various
techniques including FT-IR, NMR, elemental analysis and single
crystal analysis. Biological aspects including interaction with
DNA, antibacterial and antifungal activities of the synthesized
complexes were studied.
The diversity in structure of the organotin(IV) complexes are
attributed to the different coordination behavior of the ligands. Li-
gand with more than one donating groups such as O, N or S show
inter/intra molecular interaction and this increases the coordina-
2. Experimental
2.1. Materials
3,5-Dichloroaniline, succinic anhydride, organotin(IV) chlorides
and dioctyltin(IV) oxide were purchased from Aldrich Chemical
Company (USA) while glacial acetic acid, acetone, toluene, diethyl
⇑
Corresponding author. Tel.: +92 51 90642130; fax: +92 51 90642241.
E-mail addresses: drsa54@yahoo.com (S. Ali), corrado.rizzoli@unipr.it (C. Rizzoli).
0020-1693/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.ica.2013.01.025

160
F.A. Shah et al. / Inorganica Chimica Acta 400 (2013) 159–168
ether, and chloroform were obtained from Merck Chemicals
(Germany). Acetone, toluene, diethyl ether, and chloroform were
purified before use by the methods reported in literature [15].
3.41; N, 5.34%. IR (4000–200 cmꢀ1, KBr): 3435
(NH); 1709 (amide C@O); 1565 (asym CO); 1335
230 (
); 1H NMR (CDCl3, 300 MHz) d (ppm): 7.10 (s, 2H; 2,6);
m
(OH); 3388
m
m
m
m
(sym CO);
D
m
7.68 (s, 1H, H4); 2.04–2.07 (d,d 3J(1H, 1H) = 9.0 Hz, 2H, H8); 2.15–
2.12 (d,d 3J(1H, 1H) = 9.0 Hz, 2H, H9); 9.5 (s, 1H NH); 13C NMR
(CDCl3-d3, 75 MHz) d (ppm): 141.3 (C1); 117.2 (C2,6); 134.6
(C3,5); 122.5 (C4); 170.7 (C7); 29.8 (C8); 31.3 (C9); 173.5 (C10);
EI-MS, m/z (%): [C3H3O]+ 55 (100), [C3H5O]+ 57 (21), [C6H5]+ 77
(15), [C5H3]+ 63 (71), [C3H5NO]+ 71 (46), [C10H8NO3Cl2]+ 261 (8),
[C6H4NCl2]+ 161 (85).
2.2. Physical measurements
The melting point was determined in a capillary tube using a
Gallenkamp (UK) electrothermal melting point apparatus. IR spec-
trum in the range of 4000–200 cmꢀ1 was obtained on a Thermo
Nicolet-6700 FT-IR Spectrophotometer. Microanalysis was done
using a Leco CHNS 932 apparatus. 1H and 13C NMR were recorded
on a Bruker-300 MHz FT-NMR Spectrometer, using CDCl3 as an
internal reference [1H (CDCl3) = 7.25 and 13C (CDCl3) = 77]. Chemi-
cal shifts are given in ppm and coupling constants (J) values are gi-
ven in Hz. The multiplicities of signals in 1H NMR are given with
chemical shifts (s = singlet, d = doublet, t = triplet, m = multiplet).
119Sn NMR spectra were recorded in CDCl3 with a 400 MHz JEOL
ECS instrument. The measurements were recorded at a working
frequency of 149.4 MHz and the chemical shifts were referenced
to Me4Sn as an external standard. The absorption spectrum was
measured on a Shimadzu 1800 UV–Vis Spectrophotometer. The
X-ray diffraction data were collected on a Bruker SMART APEX
2.3.2. Synthesis of organotin(IV) complexes R3SnL with R = Me (1),
n-Bu (2), Ph (3), and [R2SnL2] with R = Me (4), n-Bu (5)
Organotin(IV) carboxylates were synthesized by refluxing for
8 h the mixture of R3SnCl (3.8 mmol; R = Me, 0.75 g for 1; R = n-
Bu, 1.25 g for 2; R = Ph, 1.47 g for 3, i.e., 1:1 ratio of ligand and
R3SnCl) or R2SnCl2 (3.8 mmol; R = Me, 0.84 g for 4; R = n-Bu,
1.16 g for 5, i.e., 2:1 ratio of ligand and R2SnCl2) and ligand HL
(1.98 g, 7.6 mmol) in the presence of Et3N (0.53 mL, 3.8 mmol for
R3SnCl and 1.06 mL, 7.6 mmol for R2SnCl2) in dry toluene
(100 mL) (Scheme 3). The refluxed solution was kept for overnight
at room temperature. The precipitated Et3NH+Clꢀ salt was removed
by filtration. The filtrate was concentrated to dryness under re-
duced pressure. The product was purified by recrystallization from
a chloroform/methanol (4:1 v/v) mixture at room temperature. The
numbering of HL and alkyl group attached to Sn is given in
Scheme 2.
CCD diffractometer, equipped with
a 4 K CCD detector set
60.0 mm from the crystal. The crystals were cooled to 100 1 K
using the Bruker KRYOFLEX low temperature device and intensity
measurements were performed using graphite monochromated
Mo Ka radiation from a sealed ceramic diffraction tube (SIEMENS).
Generator settings were 50 kV/40 mA. The structure was solved by
Patterson methods and extension of the model was accomplished
by direct methods using the program DIRDIF or SIR2004. Final
refinement on F2 carried out by full-matrix least squares tech-
niques using SHELXL-97, a modified version of the program PLUTO
(preparation of illustrations) and PLATON package. Electron impact
(70 eV) mass spectra were recorded on a Kratos MS25RFA.
The m/z values were evaluated assuming that H = 1, C = 12,
N = 14, O = 16, Cl = 35 and Sn = 120.
2.3.3. Synthesis of [R2SnL2] with R = Oct (6)
Dioctyltin carboxylate was synthesized by refluxing a mixture
of Oct2SnO (1.38 g, 3.8 mmol) and ligand HL (1.98 g, 7.6 mmol),
i.e., 2:1 ratio of ligand and R2SnCl2, for 8 h with continuous removal
of water (Scheme 3). After cooling mixture to room temperature,
the product was purified by recrystallization from a chloroform/
n-hexane (4:1 v/v) mixture at room temperature.
2.3.3.1. Trimethyltin(IV) 3-[(30,50-dimethylphenylamido)]propanoate
(1). M.p. 190–192 °C: Mol. Wt.: 424.89: Molecular formula C13H17-
Cl2NO3Sn: Anal. Calc.: C, 36.62; H, 3.99; N, 3.29. Found: C, 36.58; H,
2.3. Synthesis
3.94; N, 3.26%. IR (4000–200 cmꢀ1, KBr): 3382
m
(NH), 1699
(sym CO), 134 ( ), 549
m
(Sn–O). 1H NMR (CDCl3, 300 MHz) d (ppm): 7.28
m
2.3.1. Synthesis of 3-[(30,50-dimethylphenylamido)]propanoic acid
(HL)
(amide C@O), 1560
(Sn–C), 412
m
(asym CO), 1426
m
Dm
m
(s, 2H, H2,6); 7.48 (s, 1H, H4); 2.63–2.60 (d,d 3J(1H, 1H) = 9.0 Hz,
2H, H8); 2.77–2.74 (d,d 3J(1H, 1H) = 9.0 Hz, 2H, H9); 9.8 (s, 1H
NH); 0.51 (s, 9H, Sn–CH3) 2J[117/119Sn, 1H] [56.7, 59.9]; 13C NMR
(CDCl3, 75 MHz) d (ppm): 141.5 (C1); 117.6 (C2,6); 135.1 (C3,5);
123.7 (C4); 171.0 (C7); 30.6 (C8); 32.5 (C9); 175.4 (C10); (ꢀ2.2
1J[117/119Sn–13C] [380, 398] methyl carbon). 119Sn NMR (CDCl3,
ppm): 140: EI-MS, m/z (%): [Sn]+ 120 (54), [C3H3O]+ 55 (100),
[C3H5O]+ 57 (56), [C6H5]+ 77 (16), [C5H3]+ 63 (9), [C3H5NO]+ 71
(22), [C6H4NCl2]+ 161 (3), [C7H4OCl2N]+ 189 (22).
A solution of succinic anhydride (5 mmol) in glacial acetic acid
(25 mL) was added to a solution of 3,5-dimethylaniline solution
(5 mmol) in glacial acetic acid (25 mL). The mixture was stirred
overnight at room temperature. The resulting white solid product
was subsequently filtered and washed with cold distilled water
in order to remove impurities and byproducts. The product thus
obtained was recrystallized from acetone. The chemical reaction
is shown in Scheme 1.
M.p. 164–165 °C: Mol. Wt.: 261: Molecular formula C10H9Cl2-
NO3: Anal. Calc.: C, 45.80; H, 3.44; N, 5.34. Found: C, 45.78; H,
2.3.3.2. Tri-n-buthyltin(IV) 3-[(30,50-dimethylphenylamido)]propano-
ate (2). M.p. 69–70 °C: Mol. Wt.: 551.13: Molecular formula C22-
H35Cl2NO3Sn: Anal. Calc.: C, 47.83; H, 6.34; N, 2.54. Found: C,
O
O
O
47.79; H, 6.30; N, 2.51%. IR (4000–200 cmꢀ1, KBr): 3383
m
(NH),
..
(i) glacial CH3COOH
1694
m
(amide C@O), 1548
m (asym CO), 1442 m (sym CO), 106
R-NH2
O
O
+
(Sn–O). 1H NMR (CDCl3, 300 MHz) d
N
(ii) 24 h
(iii) Room temp
OH
(D
m), 586
m
(Sn–C), 454 m
R
(ppm): 7.28 (s, 2H, H2,6); 7.43 (s, 1H, H4); 2.59–2.56 (d,d 3J(1H,
1H) = 9.0 Hz, 2H, H8); 2.78–2.75 (d,d 3J(1H, 1H) = 9.0 Hz, 2H, H9);
H
9.6 (s, 1H NH); 0.88 (t, 3H, Hd); 1.22–1.65 (m, 6H, Ha,b,c
); 13C
NMR (CDCl3, 75 MHz) d (ppm): 140.2 (C1); 117.5 (C2,6); 134.9
R =
Cl
(C3,5); 123.5 (C4); 171.1 (C7); 30.4 (C8); 32.3 (C9); 174.9 (C10);
(29.7, 1J[117/119Sn–C ] [335, 351], 28.0, 2J[117/119Sn–Cb] [20.3],
a
Cl
26.3, 3J[117/119Sn–C
c
] [65.3], 14.4, Cd); 119Sn NMR (CDCl3, ppm):
Scheme 1. Chemical reaction and structural representation of ligand (HL).
108: EI-MS, m/z (%): [C8H6NOClSn]+ 287 (2), [C8H6NOSn]+ 252

F.A. Shah et al. / Inorganica Chimica Acta 400 (2013) 159–168
161
(C4); 171.4 (C7); 30.0 (C8); 31.9 (C9); 175.3 (C10); (29.7 methyl
carbon); 119Sn NMR (CDCl3, ppm): ꢀ180: EI-MS, m/z (%): [C9H8-
NOClSn]+ 301 (5), [C8H6NOClSn]+ 287 (11), [Sn]+ 120 (15),
[C3H3O]+ 55 (100), [C3H5O]+ 57 (45), [C6H5]+ 77 (8), [C5H3]+ 63
(14), [C3H5NO]+ 71 (22), [C10H8NO3Cl2]+ 261 (28), [C6H4NCl2]+
161 (21), [C7H4OCl2N]+ 189 (14).
α
γ
α
δ
Sn
Sn
CH3
Sn
CH3
β
γ
β
2.3.3.5. Di-n-buthyltin(IV) 3-[(30,50-dimethylphenylamido)]propano-
ate (5). M.p. 128–130 °C: Mol. Wt.: 754.02: Molecular formula
α
δ
C
28H34Cl4N2O6Sn: Anal. Calc.: C, 44.44; H, 4.490; N, 3.17. Found: C,
44.41; H, 4.47; N, 3.15%. IR (4000–200 cmꢀ1, KBr): 3379
(NH),
1703 (amide C@O), 1565 (asym CO), 1435 (sym CO), 130
), 564 (Sn–C), 422
m
O
Cl
O
m
m
m
m
(Sn–O); 1H NMR (CDCl3, 300 MHz) d
3
5
2
(D
m
m
7
C
10 C
(ppm): 7.23 (s, 2H, H2,6); 7.39 (s, 1H, H4); 2.43–2.40 (d,d 1J(1H,
1H) = 9.0 Hz, 2H, H8); 2.55–2.51 (d,d 3J(1H, 1H) = 9.0 Hz, 2H, H9);
O-
N
4
8
9
H
1
9.5 (s, 1H NH); 0.79 (t, 3H, Hd); 1.3–1.59 (m, 6H, Ha,b,c
); 13C NMR
6
(CDCl3, 75 MHz) d (ppm): 141.6 (C1); 117.6 (C2,6); 136.5 (C3,5);
Cl
123.7 (C4); 171.2 (C7); 31.3 (C8); 32.3 (C9); 174.6 (C10); (30.0
(Ca), 27.6 (Cb), 26.4 (Cc
), 14.0 (Cd); 119Sn NMR (CDCl3, ppm):
Scheme 2. Numbering pattern of HL and organotin moiety.
ꢀ200: EI-MS, m/z (%): [C10H8NO3ClSn]+ 345 (3), [Sn]+ 120 (6),
[C3H3O]+ 55 (47), [C3H5O]+ 57 (100), [C6H5]+ 77 (10), [C5H3]+ 63
(8), [C3H5NO]+ 71 (6), [C10H8NO3Cl2]+ 261(9), [C7H4OCl2N]+ 189 (6).
Toluene
Et3N
(1)
R3SnL + Et3NHCl
HL + R3SnCl
2.3.3.6. Dioctyltin(IV) 3-[(30,50-dimethylphenylamido)]propanoate
R= Me (1), Bu (2), Ph (3)
(6). Physical state: jelly like: Mol. Wt.: 867.31: Molecular formula
Toluene
2Et3N
(2)
(3)
R2SnL2 + 2Et3NHCl
2HL + R2SnCl2
C
36H50Cl4N2O6Sn: Anal. Calc.: C, 49.77; H, 5.76; N, 3.22. Found: C,
49.74; H, 5.72; N, 3.18%. IR (4000–200 cmꢀ1, KBr): 3387
(NH),
1695 (amide C@O), 1544 (asym CO), 1407 (sym CO), 137
), 540 (Sn–C), 471
(Sn–O); 1H NMR (CDCl3, 300 MHz) d
m
R= Me (4), Bu (5)
m
m
m
(D
m
m
m
Toluene
R2SnL2 + H2O
2HL + R2SnO
R= Oct (6)
(ppm): 7.20 (s, 2H, H2,6); 7.48 (s, 1H, H4); 2.63–2.60 (d,d 3J(1H,
1H) = 9.0 Hz, 2H, H8); 2.79–2.76 (d,d 3J(1H, 1H) = 9.0 Hz, 2H, H9);
9.7 (s, 1H NH); 0.84–1.60 (m, 34H, octyl protons); 13C NMR (CDCl3,
75 MHz) d (ppm): 142.1 (C1); 117.6 (C2,6); 135.2 (C3,5); 124.0
(C4); 170.2 (C7); 31.8 (C8); 31.9 (C9); 175.3 (C10); (34.2, 31.9,
29.7, 29.6, 29.4, 25.8, 25.4, 22.8, n-octyl carbons); 119Sn NMR
(CDCl3, ppm): ꢀ149: EI-MS, m/z (%): [C9H8NOClSn]+ 345 (2), [Sn]+
120 (8), [C3H3O]+ 55 (46), [C3H5O]+ 57 (100), [C6H5]+ 77 (10),
[C5H3]+ 63 (13), [C3H5NO]+ 71 (16), [C10H8NO3Cl2]+ 261 (8), [C7H4-
OCl2N]+ 189 (7).
Scheme 3. General procedure for the synthesis of organotin(IV) compounds.
(8.22), [Sn]+ 120 (3), [C3H3O]+ 55 (100), [C3H5O]+ 57 (46), [C6H5]+
77 (2), [C5H3]+ 63 (4), [C3H5NO]+ 71 (15), [C10H8NO3Cl2]+ 261 (4),
[C6H4NCl2]+ 161 (10), [C7H4OCl2N]+ 189 (21).
2.3.3.3. Triphenyltin(IV) 3-[(30,50-dimethylphenylamido)]propanoate
(3). M.p. 189–190 °C; Mol. Wt.: 611.01: Molecular formula C28H23-
Cl2NO3Sn: Anal. Calc.: C, 52.46; H, 3.55; N, 3.83. Found: C, 52.42; H,
2.4. DNA interaction study by UV–Vis spectroscopy
3.52; N, 3.80%. IR (4000–200 cmꢀ1, KBr): 3375
m
(NH), 1686
(sym CO), 120 ( ), 541
m
(Sn–O); 1H NMR (CDCl3, 300 MHz) d (ppm): 7.27
m
SS-DNA (50 mg) was dissolved and stirred for overnight in dou-
ble deionized water (pH 7.0) and kept at 4 °C. Doubly distilled
water was used to prepare buffers (20 mM Phosphate buffer
(NaH2PO4–Na2HPO4), pH 7.2). A solution of (SS-DNA) in the buffer
gave a ratio of UV absorbance at 260 and 280 nm (A260/A280) of 1.8,
indicating that the DNA was sufficiently free of protein [16]. The
DNA concentration was determined via absorption spectroscopy
using the molar absorption coefficient of 6600 Mꢀ1 cmꢀ1
(260 nm) for SS-DNA [17] and was found to be 1.86 ꢁ 10ꢀ5 M.
The compound was dissolved in 70% ethanol at a concentration
of 3.7 ꢁ 10ꢀ5 M. The UV absorption titrations were performed by
keeping the concentration of the compound fixed while varying
the SS-DNA concentration. Equivalent solutions of SS-DNA were
added to the complex and reference solutions to eliminate the
absorbance of DNA itself. Compound–DNA solutions were allowed
to incubate for 30 min at room temperature before measurements
were made. Absorption spectra were recorded using cuvettes of
1 cm path length at room temperature (25 1 °C).
(amide C@O), 1583
(Sn–C), 438
m
(asym CO), 1463
m
Dm
m
(s, 2H, H2,6); 7.41(s, 1H, H4); 2.45–2.42 (d,d 3J(1H, 1H) = 9.0 Hz,
2H, H8); 2.54–2.51 (d,d 3J(1H, 1H) = 9.0 Hz, 2H, H9); 10.4 (s, 1H
NH); 7.28–7.7 (m, 15H phenyl protons); 13C NMR (CDCl3,
75 MHz) d (ppm): 142.2 (C1); 117.4 (C2,6); 136.5 (C3,5); 123.2
(C4); 171.0 (C7); 31.2 (C8); 32.0 (C9); 176.0 (C10); (137.0, 136.7,
129.2, 128.6, phenyl carbons); 119Sn NMR (CDCl3, ppm): ꢀ148:
EI-MS, m/z (%): [C9H8NOClSn]+ 301 (25), [C8H6NOClSn]+ 287 (5),
[C8H6NOSn]+ 252 (12), [Sn]+ 120 (42), [C3H3O]+ 55 (25), [C3H5O]+
57 (20), [C6H5]+ 77 (100), [C5H3]+ 63 (62), [C3H5NO]+ 71 (8), [C10H8-
NO3Cl2]+ 261 (7), [C6H4NCl2]+ 161 (2), [C7H4OCl2N]+ 189 (9).
2.3.3.4. Dimethyltin(IV) 3-[(30,50-dimethylphenylamido)]propanoate
(4). Semisolid: Mol. Wt.: 669.93: Molecular formula C22H22Cl4N2-
O6Sn: Anal. Calc.: C, 39.23; H, 3.27; N, 4.16. Found: C, 39.20; H,
3.25; N, 4.14%. IR (4000–200 cmꢀ1, KBr): 3385
m
(NH), 1707
(sym CO), 117 ( ), 518
(Sn–O); 1H NMR (CDCl3,300 MHz) d (ppm): 7.20
m
(amide C@O), 1556
(Sn–C), 426
m
(asym CO), 1439
m
Dm
m
m
2.5. Viscosity measurements
(s, 2H, H2,6); 7.43 (s, 1H, H4); 2.63–2.60 (d,d 3J(1H, 1H) = 9.0 Hz,
2H, H8); 2.76–2.79 (d,d 3J(1H, 1H) = 9.0 Hz, 2H, H9); 9.9 (s, 1H
NH); 0.28 (t, 6H, Sn–CH3), 2J[119Sn, 1H] [80.0]; 13C NMR (CDCl3,
75 MHz) d (ppm): 141.9 (C1); 117.8 (C2,6); 135.1 (C3,5); 124.0
Viscosity measurements were carried out using Ubbelohde vis-
cometer at room temperature (25 1 °C). Flow time was measured
with a digital stopwatch. Each sample was measured three times

162
F.A. Shah et al. / Inorganica Chimica Acta 400 (2013) 159–168
and an average flow time was calculated. Data were presented as
relative viscosity, (
1/3, versus binding ratio ([HL]/[DNA]) where
is the viscosity of DNA in the presence of complex and go is the
viscosity of DNA alone. Viscosity values were calculated from the
for the alkyl as well as aryl groups attached to tin atom appeared in
their specific region [27]. nJ[119Sn,13C] couplings provided impor-
tant information about the structure of organotin(IV) carboxylates.
In trimethyltin (1) and tributyltin (2) complexes, the coupling
constants 1J[117/119Sn,13C] were observed at 398, 380 Hz and at
335, 351 Hz, respectively in CDCl3 solution. The position of tin-car-
bon satellite for the complex (1) and (2) reflect tetrahedral geom-
etry around the tin in solution. It means that the ligand in the
solution loses its bidentate nature and the trioganotin(IV) com-
plexes exist as a four coordinated structure in solution [28]. How-
g/go)
g
observed flow time of DNA containing solution (to),
[18–20].
g
= t ꢀ to
3. Results and discussion
3.1. FT-IR spectra
ever, in diorganotin(IV) complexes,
a fluxional behavior of
carboxylate oxygen in coordination with organotin(IV) moiety
cause a difficulty in assigning exact geometry and these complexes
appear as skew trapezoidal geometry which is of six coordination
numbers [29].
FT-IR data of organotin(IV) derivatives reflect valuable informa-
tion about the structure of the complexes in the solid state. The
values to different vibrational bands were assigned by comparing
the FT-IR spectrum of the free ligand with those of the complexes.
The disappearance of the characteristic broad band at
The 119Sn NMR spectra of complexes show only a sharp singlet
indicating the formation of a single species. However, these values
are strongly dependent on the nature and orientation of the organ-
ic groups bonded to tin. The shifts observed in complexes can be
explained quantitatively in terms of an increase in electron density
on the tin atom as the coordination number increases. The 119Sn
chemical shift values measured in non-coordinating solvent for
the synthesized compounds show penta-coordination around tin,
with trigonal bipyrimidal geometry.
3435 cmꢀ1 due to
m (OH) stretching frequency in the spectra of
the complexes and the appearance of new peak for Sn–O linkage
at 412–471 cmꢀ1 indicates the formation of complex [21,22]. The
peaks appearing in the range of 541–586 cmꢀ1 in the spectra of
the synthesized complexes were assigned to Sn–C bond [23,24].
The
m (N–H) band in the spectrum of the ligand is also present in
the spectra of the complexes in the range of 3375–3388 cmꢀ1
which shows that nitrogen is not involved in bonding with tin
atom. The bonding behavior of the ligand is proposed on the basis
Eqs. (1)–(3) [30–32] can be used to correlate the coordination
pattern of tin(IV) in di- and trimethyltin(IV) derivatives with the
1,2J[119Sn,13C] and 2J[119Sn,1H] coupling constants: in tetra-coordi-
nated tin compounds (h 6 112°) 1Js are predicted to be smaller
than about 400 Hz, whereas 2Js should be below 60 Hz; for pen-
ta-coordinated tin (h = 115–130°), 1Js fall in the 450–670 Hz range
and the 2Js fall in the 65–80 Hz range; finally, for hexa-coordinated
tin (h = 135°) 1Js and 2Js are generally larger than 670 and 83 Hz,
respectively [33]. For methyltin compounds, Eq. (2) can be used
to give relationship between the magnitude of |2J(119Sn,1H)| and
the Me–Sn–Me angle h. A similar behavior in principle is found
for 1J(119Sn,13C) but the magnitude of this coupling is less predict-
able. Eq. (4) can be used to relate the bond angle C–Sn–C (h) for
nBu2Sn [34,35]. In the present study the h values for trimethyl-
tin(IV) is 112o which confirm the tetrahedral geometry around
the tin in solution. In case of dimethyltin(IV) the h values is
130.8o which confirm the hexa coordination around the tin in solu-
tion (Table 1).
of the difference of
D
m
= (masym
ꢀ
msym)COO [24]. The magnitude of
the
D
m
for the reported complexes is in the range 106–137 cmꢀ1
which reflects the bidentate nature of the ligand.
3.2. Multinuclear (1H, 13C and 119Sn) NMR spectroscopy
Multinuclear NMR spectral data (1H, 13C and 119Sn) for the syn-
thesized ligand and its organotin derivatives are recorded in CDCl3
solution, and are given in experimental part. The characteristic
peak for the OH bond in the spectrum of the ligand which appears
at 11.1 ppm is not present in the spectra of the complexes which
shows that the complexation of the ligand to organotin(IV) species
occur through oxygen atom of carboxylate group. The presence of
NH signal in the spectra of the complexes indicates that nitrogen is
not involved in coordination to tin. The phenyl protons at position
2 and 6 are in the range of 7.10–7.28 ppm while at position 4 it is in
the range of 7.39–7.68 ppm.
The methyl proton in trimethyltin(IV) complex (1) and dimeth-
yltin(IV) complex (4), give characteristic signal at 0.52 ppm with
2J[117/119Sn–1H] = 57, 60 Hz and 0.28 ppm with 2J[119Sn–1H] = 80 Hz
which indicate tetrahedral geometry for (1) and penta or hexa coor-
dination for (4) in non-coordinating solvent [25,26].
In case of butyl groups, a clear triplet is observed for terminal
methyl groups at 0.88 and 0.79 ppm for complexes (2) and (5),
respectively while the protons of other carbon atoms give complex
pattern as multiplet signals. In case of octyltin(IV) complex, a
somewhat different and complex pattern is observed for the meth-
ylene protons. The terminal protons give triplet while the remain-
ing protons give broad and complex signals. A complex pattern for
aromatic protons in case of triphenyltin (3) is observed in the range
of 7.28–7.7 ppm.
1
j Jð119Sn;13CÞj ¼ 11:4h ꢀ 875
ð1Þ
ð2Þ
ð3Þ
ð4Þ
2
h ¼ 0:0161j Jð119Sn;1HÞj ꢀ 1:32j Jð119Sn;1HÞj þ 133:4
2
2
1
j Jð119Sn;13CÞj ¼ ð10:7 ꢂ 0:5Þh ꢀ ð778 ꢂ 64Þ
1
j Jð119Sn;13CÞj ¼ 9:99ðꢂ0:73Þh ꢀ 746ðꢂ100Þ
3.3. Mass spectrometry
Electron impact method was used to obtain the mass spectral
data at 70 eV for the ligand and its complexes. The data is given
in experimental part along with the synthesis of compounds.
The resultant fragments were in good agreement with the
expected structure of the complexes. In the mass spectral data
for complexes, characteristic pattern of tin was observed. This
characteristic pattern is important for the characterization of the
synthesized complexes because it provided information about
the metal–ligand bond and the rout of fragmentation.
The 13C NMR data of the ligand and their complexes were in
agreement with the 1H NMR and FT-IR data for the formation of
complexes. The values were assigned to each carbon of the ligand
and its complexes on the basis of incremental method and on com-
parison with literature values. On comparing the spectra of the
complexes with the spectrum of the ligand, downfield shift is ob-
served in the position of signals for the carboxylate carbons. This
shows the participation of carboxylate group in complex forma-
tion. However, the signals for –C–N–, –CH2–CH2–, –C–Cl and peaks
In complexes the fragmentation takes place by the loss of an al-
kyl or aryl group followed by the elimination of CO2. Fragmenta-
tion process proceeds by the breaking of ligand in steps. Another

F.A. Shah et al. / Inorganica Chimica Acta 400 (2013) 159–168
163
Table 1
meric form and the tin atom is coordinated to only one ligand
through one oxygen atom (O1) and the second oxygen (O2) re-
mains free. In triphenyltin(IV) complex tin atom is tetracoordinat-
ed due to the bulky groups (phenyl) attached to tin atom which
create steric hindrance and prevent the approach of next ligand
to that tin atom.
Due to the electrostatic effect of uncoordinated oxygen atom
(O2), the phenyl group of C17 in case of complex (3) is pulled to-
wards O1 and away from other two phenyls. Thus the angles
around the central tin atom deviated from normal 109°, i.e., the
C17–Sn–O1 decreases to 94.99(10)° while C11–Sn1–C23 angle in-
creases to 118.77(13)°. These deviations distort the geometry
around the tin atom from normal to distorted tetrahedral.
Crystal data and structure refinement parameters for complexes 2 and 3.
2
3
Moiety formula
Formula weight
Crystal system
Space group
a (Å)
C
44H70Cl4N2O6Sn2
C28H23Cl2NO3Sn
611.06
monoclinic
P21/c
10.361(3)
27.083(5)
9.692(2)
90.00
97.902(7)
90.00
2693.8(11)
0.794–0.867
4
1.507
1224
1102.20
monoclinic
C2/c
47.1867(14)
10.1593(3)
25.3842(8)
90.00
120.001(2)
90.00
10538.4(6)
2.16–26.50
8
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
V (Å3)
h Ranges for data collection (°)
Z
qcalc (g/cm3)
F(000)
1.389
4512
4. Biological applications
Crystal size (mm)
Crystal habit
T (K)
0.36 ꢁ 0.24 ꢁ 0.22
0.22 ꢁ 0.17 ꢁ 0.12
4.1. DNA binding studies
prism
block
293(2)
293(2)
c
l
(Å)
0.71073
1.193
0.71073
5563
4.1.1. Absorption spectral studies
(mmꢀ1
)
The interaction of metal complexes to DNA is often character-
ized by absorption spectral titration followed by the changes in
the absorbance and shift in the wavelength. The absorption spec-
tral changes of the representative compounds (2) and (3) in the ab-
sence and presence of SS-DNA are shown in Figs. 5 and 6,
respectively. Upon the addition of SS-DNA to complexes (2) and
(3), hyperchromism with a minor red shift of about 2 nm was ob-
served at the intraligand bands. Hyperchromism and hypochro-
Total data
Unique data (Rint
51158
10817 (0.0351)
4850
)
R1 = 0.0397
wR2 = 0.1039
R1 = 0.0510
wR2 = 0.1116
1.062
Final R indices [I P 2
R Indices (all data)
Goodness-of-fit
r
(I)]
R1 = 0.0478
wR2 = 0.1086
R1 = 0.0961
wR2 = 0.1398
1.035
3.01–25.25
4850/1/320
h Range for data collection (°)
2.16–26.50
mism are the spectral changes typical of
a metal complex
association with the DNA helix. Hypochromism results from con-
traction of the DNA helix as well as changes in its conformation,
while hyperchromism results from damage to the DNA double he-
lix structure [18]. The observed hyperchromism results due to the
positively charge Sn(IV) cations binding to DNA, presumably by a
strong electrostatic attraction to the negatively charge oxygen of
the phosphate group of the DNA backbone, thereby causing a con-
traction and overall damage to the secondary structure of DNA
[41]. The hard Lewis acid Sn(IV) atom binds electrostatically to
the phosphate backbone of the DNA helix. The intrinsic binding
constant of the compound with DNA were determined according
to Benesi–Hildebrand equation [18]:
possible path of fragmentation is the breaking of ligand and the
elimination of aryl or alkyl groups. Base peak observed in the com-
plexes (1), (2), and (4) is due to fragment [C3H3O]+ at m/z 55 (100),
while in complexes (5) and (6) is due to fragment [C3H5O]+ at m/z
57 (100), respectively. In complex (3), basepeak is due to fragment
[C6H5]+ at m/z 77 (100).
3.4. X-ray crystallography analysis
Crystal structure of the ligand has already been published ear-
lier [36].
The crystal data and structure refinement parameters for com-
plexes (2) and (3) are given in the Table 1 while the selected bond
lengths and bond angles are given in Table 2.
ORTEP diagram (Fig. 1) and unit cell packing (Fig. 2) diagram for
complex (2) show that the molecule exist in the zigzag chain poly-
meric structure due to interaction of the ligand C@O with Sn atom.
The central tin atom is penta-coordinated, i.e., the equatorial posi-
A0
eG
ꢀ
eG
eG eHꢀG
1
¼
þ
ꢁ
A ꢀ A0 eHꢀG
ꢀ eG K½DNAꢃ
where K is the association/binding constant, A0 and A are the absor-
bances of the drug and its complex with DNA, respectively, and eG
and eH–G are the absorption coefficients of the drug and the drug–
DNA complex, respectively. The association constants were ob-
tained from the intercept-to-slope ratios of A0/(A ꢀ A0) versus 1/
tion is occupied by 3-
occupied by 2 oxygen atoms of the ligands. The geometry around
Sn atom can be defined by )/60, where b is the largest
= (b ꢀ
of the basal angles around the Sn atom and is the second largest
angle of the basal angles around the Sn atom. The calculated va-
a carbons of butyl groups and axial position is
[DNA] plots. The Gibb’s free energy (DG) was determined from
the equation:
s
a
a
D
G ¼ ꢀRT lnK
s
where R is general gas constant (8.314 J Kꢀ1 molꢀ1) and T is the
temperature (298 K). The binding constant K value was found to
be 1.72 ꢁ 104 Mꢀ1 and 6.78 ꢁ 104 Mꢀ1 for complexes (2) and (3),
respectively. The interaction of the drug with DNA is a spontaneous
lue for complex (2) is 0.11 which indicates a slightly distorted trig-
onalbipyramidal arrangement around the Sn atom. The sum of the
equatorial C–Sn–C angles is 353.2° which is close to 360° and
shows that the butyl groups are in one plane [37]. The bond
lengths are in agreement with the reported triorganotin(IV) car-
boxylates [38–40]. Crystal structure shows that each ligand is coor-
dinated to two organotin species in different coordination mode.
Similarly, each organotin(IV) moiety is bonded to two ligands
through the oxygen atoms. This coordination in complex (2) results
the polymeric structure. Sn–O bond lengths suggest that the two
Sn–O bonds are not identical.
process as shown by the negative values of
DG.
4.1.2. Viscosity measurement
Binding of small molecules to DNA can change not only the heli-
cal twist, but also the contour of length and stiffness (both bending
and torsional), and can induce systematic bend into the DNA dou-
ble helix. A hydrodynamic method such as viscometric measure-
ments in which the solution viscosity of DNA is responsive to the
changes in the effective length of DNA molecule is one of the most
ORTEP and unit cell packing diagrams for triphenyltin(IV) com-
plexes (3) (Figs. 3 and 4) show that the complex exist in mono-

164
F.A. Shah et al. / Inorganica Chimica Acta 400 (2013) 159–168
Table 2
Selected bond lengths (Å) and bond angles (°) for complex 2 and 3.
Bu3SnL (2)
Bond lengths
Sn1–C21
Sn1–C25
Sn1–C29
Sn1–O1
Sn1–O5
O1–C1
O2–C1
2.141(7)
2.116(6)
2.103(7)
2.124(4)
2.669(4)
1.283(6)
1.220(7)
Sn2–C33
Sn2–C37
Sn2–C41
Sn2–O4
O4–C11
O5–C11
2.125(7)
2.114(7)
2.125(7)
2.121(5)
1.289(8)
1.218(8)
Bond angles
O1–Sn1–O5
O1–Sn1–C21
O1–Sn1–C25
O1–Sn1–C29
O5–Sn1–C21
O5–Sn1–C25
O5–Sn1–C29
C21–Sn1–C25
173.00(16)
103.7(2)
96.8(2)
90.8(3)
80.9(2)
85.7(2)
82.3(3)
116.1(3)
O4–Sn2–C33
O4–Sn2–C37
O4–Sn2–C41
C33–Sn2–C37
C33–Sn2–C41
C37–Sn2–C41
C21–Sn1–C29
C25–Sn1–C29
100.0(2)
101.5(2)
94.1(2)
124.1(3)
111.9(3)
117.3(3)
118.8(3)
120.7(4)
Ph3SnL (3)
Bond lengths
Sn1–C11
Sn1–C23
Sn1–C17
2.119(4)
2.121(3)
2.136(3)
2.069(2)
O1–C1
O2–C1
O3–C4
C1–C2
1.307(4)
1.213(4)
1.231(4)
1.510(5)
Sn1–O1
C2–C3
1.519(5)
O1–Sn1–C11
O1–Sn1–C23
O1–Sn1–C17
C11–Sn1–C23
113.54(11)
105.38(11)
94.99(10)
118.77(13)
C11–Sn1–C17
C23–Sn1–C17
C1–O1–Sn1
110.90(14)
110.61(13)
108.5(2)
C24–C23–Sn1
119.3(3)
Fig. 1. ORTEP drawing of complex (2).
decisive tests for understanding the binding mode of DNA in solu-
tion, i.e., intercalation or other binding modes. Generally an in-
crease in the relative viscosity is attributed to a length increase
of the DNA double helix due to intercalation. On the other hand,
a decrease in the relative viscosity due to the reduction of the
effective length of DNA molecules results from the bending of
the DNA double helix caused by electrostatic interaction between
the anion site of phosphate of DNA and the cation site of the mol-
ecule [42]. The values of relative viscosity (
from (t/to)1/3 ratio for all samples, where t, to,
the time and viscosity of DNA solution with and without com-
g
/
go
)
g
1/3 were calculated
and go represent
1/3
pound, respectively. (
g/go)
was plotted versus [compound]/
[DNA] ratio (Fig. 7). As it is evidenced from Fig. 7, the relative vis-
cosity of compounds (2) and (3) decreases with increasing the
[compound]/[DNA] ratio, indicating the electrostatic mode of
interaction of compounds (2) and (3) with DNA. The electrostatic

F.A. Shah et al. / Inorganica Chimica Acta 400 (2013) 159–168
165
Fig. 2. A portion of lattice of complex (2) showing unit cell packing of molecules.
Fig. 3. ORTEP drawing of complex (3).
mode of interaction of Sn(IV) complexes is due to the fact that
Sn(IV) is a hard acid and prefer to combine with a hard oxygen
base. Cationic Sn(IV) exerts electrostatic interaction towards poly-
anionic phosphate backbone of DNA as a result of its hard Lewis
acidic property, thus, neutralizing the negative charge of the DNA
resulting in significant contraction and conformational changes
in the DNA helix and finally cause breakage of the secondary struc-
ture of the DNA [42]. The same result has also observed in case of
UV–Vis spectroscopy as discussed in Section 3.4.
activity of organotin(IV) carboxylates and results are summarized
in Table 3.
The antibacterial data of the complexes show that among triorga-
notin(IV) complexes, complex (2) is more potent than the other tri-
organotin(IV) members of series against the tested strains of
bacteria. This higher activity may be attributed to lipophilicity of bu-
tyl group attached to tin atom. Among diorganotin(IV) complexes,
complex (5) exhibits highest antibacterial activity against the tested
strains of bacteria. The antibacterial activity data suggests that com-
plex (2) is more potent against tested strain of bacteria than other
synthesized complexes. Tributyltin(IV) complexes are in general
more toxic against bacteria as it blocks F0F1 ATPases [44,45].
4.2. Antibacterial activity
Four different strains of the bacteria were selected to assess the
biocidal activity of the synthesized complexes. The solution of li-
gand and each synthesized organotin(IV) carboxylate having
1.0 mg/mL strength in DMSO were used for antibacterial activity.
In vitro, agar well diffusion method [43] was used to check the
4.3. Antifungal activity
The synthesized organotin(IV) carboxylates having 1.0 mg/mL
strength in DMSO were screened for their antifungal activities using

166
F.A. Shah et al. / Inorganica Chimica Acta 400 (2013) 159–168
Fig. 4. A portion of lattice of complex (3) showing unit cell packing of molecules. Dotted lines (red color) show H-bonding. (For interpretation of the references to color in this
figure legend, the reader is referred to the web version of this article.)
Fig. 5. Absorption spectra of 3.7 ꢁ 10ꢀ5 M compound (2) in the absence (a) and presence of 13
lM (b), 26 lM (c), 39 lM (d), 52 lM DNA (e). The arrow direction indicates
increasing concentrations of DNA.
four different fungal strains. The activity is reported as percentage
Complex (1) showed highest fungicidal activity against Candida
inhibition in Table 4 using miconazole and amphotericin B as standards.
The data show that the fungicidal activity of the synthesized
complexes is significant and higher than their ligand. Among the
synthesized complexes, triorganotin(IV) derivatives of the ligand
were found to be more active against tested fungal strains than
the diorganotin(IV) derivatives probably due to vacant position at
tin atom for coordination with biological system.
glaberata and Candida albicans while complex (3) showed highest
fungicidal activity against Trichophyton longifusus and Aspergillus
flavis. In complex (1), alkyl groups are methyl, which are small in
size and tin atom can more effectively interact with the biological
system of fungi. In complex (3), the three phenyl groups are more
symmetrical than butyl groups in complex (2) and probably pass
easily through cell membrane of fungi.

F.A. Shah et al. / Inorganica Chimica Acta 400 (2013) 159–168
167
Fig. 6. Absorption spectra of 3.7 ꢁ 10ꢀ5 M compound (3) in the absence (a) and presence of 13
lM (b), 26
l
M (c), 39
lM (d), 52
l
M DNA (e). The arrow direction indicates
increasing concentrations of DNA.
Table 4
Antifungal activity (% inhibition) of ligand and its organotin(IV) complexes.
Complex
Inhibition (%)
T. longifusus A. flavis
C. glaberata C. albicans
HL
1
2
3
4
0
44
12
92
24
20
78
0
90
38
92
52
41
68
0
76
24
60
65
44
54
0
85
27
76
23
50
71
5
6
Standard drug miconazole
MIC ( g/mL) 70.0
amphotericin B miconazole miconazole
20.0 110.8 110.8
l
5. Conclusion
Fig. 7. Effects of increasing amount of compounds (2) and (3) on relative viscosity
of SS-DNA at 25 0.1 °C. [DNA] = 1.86 ꢁ 10ꢀ4 M.
Six new organotin(IV) complexes of 3-[(3,5-dichlorophenylam-
ido)]propanoic acid were synthesized and structurally character-
ized by elemental analyses, FT-IR, NMR (1H and 13C) spectral
studies, and mass spectrometry. The ligand coordinates to tin atom
via oxygen atom of the carboxylate groups. The crystal structure of
complex (2) confirms distorted trigonal-bipyrimidal geometry
around the tin atom while that of complex (3) confirms tetrahedral
geometry around the tin atom. Antifungal and antibacterial studies
reveal that the triorganotin(IV) complexes have higher activity
than their corresponding diorganotin(IV) complexes. UV–Vis spec-
troscopic result shows that complexes bind to DNA via electro-
static interaction of Sn(IV)+ moiety with the negatively charged
oxygen of phosphate group of DNA resulting in hyperchromism.
The UV–Vis Spectroscopic results are also supported by viscomet-
ric data.
Table 3
Antibacterial data of ligand and its organotin(IV) derivatives.
Complex
Zone of inhibition (mm)
E. coli
B. subtilis
S. flexenari
P. aeruginosa
HL
1
2
3
4
5
6
0
19
24
23
15
20
16
30
0
20
27
26
13
18
12
37
0
20
23
13
12
15
20
36
0
18
23
18
12
18
18
32
Imipenum

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F.A. Shah et al. / Inorganica Chimica Acta 400 (2013) 159–168
[19] M. Sirajuddin, S. Ali, A. Haider, N.A. Shah, A. Shah, M.R. Khan, Polyhedron 40 (1)
Appendix A. Supplementary material
(2012) 19.
[20] M. Tariq, N. Muhammad, M. Sirajuddin, S. Ali, N.A. Shah, M.R. Khan, M.N. Tahir,
J. Organomet. Chem. 723 (2013) 79.
[21] M. Parvez, S. Ahmad, S. Ali, M.H. Bhatti, M. Mazhar, Acta Crystallogr., Sect. E 60
(2004) m554.
[22] D. Kovala-Demertzi, V.N. Dokorou, J.P. Jasinski, A. Opolski, J. Wiecek, M.
Zervou, M.A. Demertzis, J. Organomet. Chem. 690 (2005) 1800.
[23] H.D. Yin, C.H. Wang, C.L. Ma, Chin. J. Org. Chem. 23 (2003) 475.
[24] G. Eng, X. Song, A. Zapata, A.C. de Dios, L. Casabianca, R.D. Pike, J. Organomet.
Chem. 692 (2007) 1398.
CCDC 861600 and 892252 contains the supplementary crystal-
lographic data for complexes 2 and 3, respectively. These data can
be obtained free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif. Supplemen-
tary data associated with this article can be found, in the online
version, at http://dx.doi.org/10.1016/j.ica.2013.01.025.
[25] M. Danish, S. Ali, A. Badshah, M. Mazhar, H. Masood, A. Malik, G. Kehr, Synth.
React. Inorg. Met. Org. Chem. 27 (1997) 863.
[26] H.O. Kalinowski, S. Berger, S. Braun, Carbon NMR Spectroscopy, John Wiley &
Sons, Chichester, UK, 1988.
References
[27] B. Wrackmeyer, Annu. Rep. NMR Spectrosc. 38 (1999) 203.
[28] G. Casella, F. Ferrante, G. Saielli, Inorg. Chem. 47 (2008) 4796.
[29] Imtiaz-ud-Din, M. Mazhar, K.C. Molloy, K.M. Khan, J. Organomet. Chem. 691
(2006) 1643.
[30] T.P. Lockhart, W.F. Manders, J.J. Zuckerman, J. Am. Chem. Soc. 107 (1985) 4546.
[31] T.P. Lockhart, W.F. Manders, Inorg. Chem. 25 (1986) 892.
[32] T.P. Lockhart, W.F. Manders, J. Am. Chem. Soc. 109 (1987) 7015.
[33] G. Casella, F. Ferrante, G. Saielli, Inorg. Chem. 47 (11) (2008) 4796.
[34] J. Holecek, M. Nadvornik, K. Handlir, A. Lycka, J. Organomet. Chem. 315 (1986)
299.
[35] S.J. Blunden, P.A. Cussack, D.G. Gillies, Magn. Reson. Chem. 24 (1986) 921.
[36] F.A. Shah, M.N. Tahir, S. Ali, M.A. Kashmiri, Acta Crystallogr., Sect. E 64 (2008)
o787.
[37] A.W. Addison, T.N. Rao, J. Reedijk, J.V. Rijn, G.C. Verschoor, J. Chem. Soc., Dalton
Trans. (1984) 1349.
[38] C.L. Ma, Q.F. Zhang, R.F. Zhang, L.L. Qiu, J. Organomet. Chem. 690 (2005) 3033.
[39] M.A. Mostafa, A. Amirreza, R.K. Hamid, S.W. Ng, J. Organomet. Chem. 692
(2007) 3922.
[40] M. Parvez, M.H. Bhatti, S. Ali, M. Mazhar, S.I. Qureshi, Acta Crystallogr., Sect. C
56 (2000) 327.
[41] S. Tabassum, G.C. Sharma, F. Arjmand, A. Azam, Nanotechnology 21 (2010) 1.
[42] F. Arjmand, G.C. Sharma, F. Sayeed, M. Muddassir, S. Tabassum, J. Photochem.
Photobiol., B 105 (2011) 167.
[43] A. Rehman, M.I. Choudhary, W.J. Thomsen, Bioassay Techniques for Drug
development, Harward Academic Publishers, Netherland, 2001.
[44] C.V. Ballmoos, J. Brunner, P. Dimroth, Proc. Natl. Acad. Sci. USA 101 (2004)
11239.
[1] S. Tabassum, C. Pettinari, J. Organomet. Chem. 691 (2006) 1761.
[2] C. Pellerito, L. Nagy, L. Pellerito, A. Szorcsik, J. Organomet. Chem. 691 (2006)
1733.
[3] D.K. Demertzi, J. Organomet. Chem. 691 (2006) 1767.
[4] L. Pellerito, L. Nagy, Coord. Chem. Rev. 224 (2002) 111.
[5] L. Qingshan, P. Yang, H. Wang, M. Guo, J. Inorg. Biochem. 64 (1996) 181.
[6] M.N. Xanthopoulou, S.K. Hadjikakou, N. Hadjiliadis, E.R. Milaeva, J.A. Gracheva,
V.Y. Tyurin, N. Kourkoumelis, K.C. Christoforidis, A.K. Metsios, S. Karkabounas,
K. Charalabopoulos, Eur. J. Med. Chem. 43 (2008) 327.
[7] M. Kemmer, H. Dalil, M. Biesemans, J.C. Martins, B. Mahieu, E. Horn, D. de Vos,
E.R.T. Tiekink, R. Willem, M. Gielen, J. Organomet. Chem. 608 (2000) 63.
[8] S. Shahzadi, K. Shahid, S. Ali, M. Bakhtiar, Turk. J. Chem. 32 (2008) 333.
[9] G. Matela, R. Aman, Cent. Eur. J. Chem. 10 (1) (2012) 1.
[10] M.M. Amini, A. Azadmehr, V. Alijani, H.R. Khavasi, T. Hajiashrafi, A.N. Kharat,
Inorg. Chim. Acta 362 (2009) 355.
[11] D.K. Demertzi, V. Dokorou, A. Primikiri, R. Vargas, C. Silvestru, U. Russo, M.A.
Demertzis, J. Inorg. Biochem. 103 (2009) 738.
[12] V. Chandrasekhar, P. Thilgar, A. Steiner, J.F. Bickley, Chem. Eur. J. 12 (2006)
8847.
[13] H.L. Xu, H.D. Yin, Z.J. Gao, G. Li, J. Organomet. Chem. 691 (2006) 3331.
[14] V. Chandrasekhar, K. Gopal, P. Thilagar, Acc. Chem. Res. 40 (2007) 420.
[15] W.L.F. Armaergo, C.L.L. Chai, in: Purification of Laboratory Chemical, fifth ed.,
Butterworth-Heinemann, New York, 2003.
[16] S. Dey, S. Sarkar, H. Paul, E. Zangrando, P. Chattopadhyay, Polyhedron 29
(2010) 1583.
[17] C.V. Sastri, D. Eswaramoorthy, L. Giribabu, B.G. Maiya, J. Inorg. Biochem. 94
(2003) 138.
[18] M. Sirajuddin, S. Ali, N.A. Shah, M.R. Khan, M.N. Tahir, Spectrochim. Acta, Part A
94 (2012) 134.
[45] H. Ueno, T. Suzuki, K. Kinosita Jr., M. Joshida, Proc. Natl. Acad. Sci. USA 102
(2005) 1333.