Synthesis, crystal structure and biological activities of two novel organotin(IV) complexes constructed from 12-(4-methylbenzoyl)-9,10-dihydro-9,l0-ethanoanthracene-11-carboxylic acid

Article abstract of DOI:10.1016/j.jorganchem.2009.04.040

Two complexes: [(n-Bu₂Sn)₄(L)₂O₂(OC₂H₅)₂] (1) and [(C₆H₅)₃Sn(L)] (2) (where, HL is 12-(4-methylbenzoyl)-9,10-dihydro-9,10-ethanoanthracene-11-car

Full text of DOI:10.1016/j.jorganchem.2009.04.040

Journal of Organometallic Chemistry 694 (2009) 2981–2986
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis, crystal structure and biological activities of two novel organotin(IV)
complexes constructed from 12-(4-methylbenzoyl)-9,10-dihydro-9,l0-
ethanoanthracene-11-carboxylic acid
b,
b
a
Xiaoyan Wu a, Wanli Kang a, , Dongsheng Zhu , Chaoguang Zhu , Shuren Liu
*
*
a Enhanced Oil Recovery Research Center, China University of Petroleum, Qingdao 266555, PR China
b Department of Chemistry, Northeast Normal University, 5268 Renmin Street, Changchun 130024, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Two complexes: [(n-Bu2Sn)4(L)2O2(OC2H5)2] (1) and [(C6H5)3Sn(L)] (2) (where, HL is 12-(4-meth-
ylbenzoyl)-9,10-dihydro-9,10-ethanoanthracene-11-carboxylic acid) have been prepared and structur-
ally characterized by means of elemental analysis and vibrational, 1H NMR and FT-IR spectroscopies.
The crystal structures of 1 and 2 have been determined by X-ray crystallography. Three distannoxane
Received 23 March 2009
Received in revised form 24 April 2009
Accepted 28 April 2009
Available online 7 May 2009
rings are present to the centrosymmetric dimeric tetraorganodistannoxane by virtue of
l3-oxo form
the central R4Sn2O2 core with a planar Sn2O2 ring, resulting in a ladder type structural motif in the molec-
ular structure of 1, and five-coordinated tin atoms are present in the distannoxane dimer. While the
molecular of 2 adopts a monomeric distorted tetrahedral configuration with the carboxylate ligand coor-
dinating in a monodentate mode. Both 1 and 2 exhibited good antibacterial and antitumour activities and
have a potential to be used as drugs.
Keywords:
Organotin(IV) carboxylates
Synthesis
Crystal structure
Biological activity
Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction
thesis of new organotin carboxylates with different structural fea-
tures will be beneficial in the development of pharmaceutical
The increasing interest in organotin(IV) carboxylates that has
arisen in the last few decades is attributed to their significantly
important biological properties like antiviral and anticancer
agents, in vitro antibacterial and antifungal agents, wood preserva-
tives and pesticides, etc. [1–11]. Several di- and tri-species have
shown potential as antineoplastic and antituberculosis agents [4–
7,12]. In general, triorganotin(IV) compounds display a larger array
of biological activity than their di- and mono-organotin(IV) ana-
logues. This has been attributed to their ability to bind proteins
[13]. Organotin carboxylates are also of interests in view of their
considerable structural diversity. Depending on the carboxylic acid
used and the stoichiometry of the reactants, several products such
as monomers, dimers, tetramers, oligomeric ladders, and hexa-
meric drums can be isolated [14–18]. Steric and electronic attri-
butes of organic substituents on tin and/or the carboxylate
moiety impart significant influence on the structural characteris-
tics in tin carboxylates. The biochemical activity of organotin com-
pounds is also influenced greatly by the structure of the molecule
and the coordination number of the tin atoms [19]. Therefore, syn-
organotin and in other properties and application.
However, up to now organotin esters of 12-(4-methylbenzoyl)-
9,10-dihydro-9,10-ethanoanthracene-11-acid were not reported in
the literatures, to our knowledge. In order to study the structure–
activity relationships of such complexes, we synthesized and char-
acterized two novel complexes, [(n-Bu2Sn)4(L)2O2(OC2H5)2] (1) and
[(C6H5)3Sn(L)] (2) (where, HL is 12-(4-methylbenzoyl)-9,10-dihy-
dro-9,10-ethanoanthracene-11-carboxylic acid). Single crystal
X-ray diffraction shows that three distannoxane rings are present
to the centrosymmetric dimeric tetraorganodistannoxane by virtue
of l3-oxo form the central R4Sn2O2 core with a planar Sn2O2 ring,
resulting in a ladder type structural motif in the molecular struc-
ture of complex 1, and five-coordinated tin atoms are present in
the distannoxane dimer. While the molecular of complex 2 adopts
a monomeric distorted tetrahedral configuration with the carbox-
ylate ligand coordinating in a monodentate mode. The antibacte-
rial and antitumour activities of
preliminary tested in vitro.
1 and 2 have also been
2. Experimental
2.1. General and instrumental
* Corresponding authors. Tel.: +86 13589332193 (W. Kang), +86 13009010567
(D. Zhu).
The reagents were used as supplied while the solvents were
purified according to standard procedures [20]. Melting points
E-mail addresses: Kangwanli@126.com (W. Kang), zhuds206@nenu.edu.cn
(D. Zhu).
0022-328X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2009.04.040

2982
X. Wu et al. / Journal of Organometallic Chemistry 694 (2009) 2981–2986
were determined in open capillaries and were not corrected. Ele-
mental analyses were carried out on a Perkin–Elmer PE 2400
CHN instrument and gravimetric analysis for Sn. 1H NMR spectra
were recorded in CDCl3 on a Varian Mercury 300 MHz spectrome-
ter. Infrared spectra (KBr pellets) were recorded on an Alpha Cent-
auri FI/IR spectrometer (400–4000 cmꢀ1 range). The ligand HL was
prepared by a modified literature method [21].
plated on the surface of the petri-dishes prepared before. Then four
wells of 3 mm diameter were made carefully and these were com-
pletely filled with the test solutions (concentration is 200 lg/ml in
ethanol), other wells containing ethanol and the reference antibac-
terial drug served as negative and positive controls, respectively.
After the bacteria were incubated for 24 h at ca. 37 °C, the diameter
of the inhibiting area around each hole was estimated, which is de-
scribed as the inhibiting effect against bacteria [27]. The average of
three diameters was calculated for each sample.
2.2. X-ray crystallography
Crystals of 1 and 2 were grown by slow evaporation of ethanol
solution at room temperature. The colorless crystals were mounted
on a sealed tube and used for data collection. Single-crystal X-ray
diffraction data for these complexes were recorded on a Bruker
2.3.2. MTT assay
Hela cell lines were grown in vitro in culture media containing
10% NCS, 1% HEPES and 1% RPMI1640 in a 5% CO2 incubator at
37 °C. The effects of di-n-butyltin oxide and complexes 1 and 2
on cell growth were evaluated using the MTT assay [28]. A total
of 2 ꢁ 103 cells were seeded in the wells of 96-well plate and cul-
tured for 24 h. Thereafter, the cells were treated with various con-
centrations (DMSO as solvent) of di-n-butyltin oxide and
complexes for 24 h. After exposure to the drug, the MTT assay
was carried out with Tetra Color One. All experiments were per-
formed at least three times and the mean percentage of prolifera-
tion was calculated.
CCD Area Detector diffractometer by using the u/
x scan technique
with Mo K radiation (k = 0.71073 Å). Absorption corrections were
a
applied by using multi-scan techniques [22]. The structures were
solved by direct methods with SHELXS-97 [23] and refined by full-
matrix least squares with SHELXL-97 [24] within WINGX [25]. All
non-hydrogen atoms were refined with anisotropic temperature
parameters, hydrogen atoms were refined as rigid groups. A sum-
mary of the crystal data, experimental details and refinement re-
sults are listed in Table 1.
2.4. Synthesis
2.3. Biological studies
2.4.1. Synthesis of 9,10-dihydroanthracene-9,10-a,b-butanedioic
2.3.1. Antibacterial tests
anhydride
The antibacterial activities were determined by using the agar
well diffusion method [26]. Broth culture medium was prepared
by mixing 10 g of albumin, 3 g of beef cream, 5 g of sodium chlo-
ride and 1000 ml distilled water at 37 °C. About 5 ml of broth cul-
ture medium was poured into the petri-dishes and allowed to
solidify. About 0.2 ml of broth culture medium containing approx-
imately 10 ꢁ 106 CFU/ml of Colon or Hay bacillus was uniformly
About 5.0 g (0.028 mol) anthracene, 2.75 g (0.028 mol) maleic
anhydride and 52 ml xylene were added to a 100 ml three-neck
boiling flask. The reaction mixture was refluxed for 2 h under stir-
ring, then cooled to room temperature. The product crystallized
under ice-water bath for 30 min, then filtrated off and washed with
several milliliters of ethanol. The pure product was obtained as a
white crystals. m.p. 265–266 °C, 82%.
Table 1
Crystal data and details of structure refinement parameters for complex 1 and 2.
Complex
1
2
Empirical formula
Formula weight
T (K)
C86H120O10Sn4
1788.58
293(2)
C43H34O3Sn
717.39
273(2)
Crystal size (mm)
Wavelength (Å)
Crystal system
Space group
0.372 ꢁ 0.352 ꢁ 0.278
0.311 ꢁ 0.279 ꢁ 0.254
0.71073
0.71073
Monoclinic
P2(1)/n
Triclinic
ꢀ
P1
Unit cell dimensions
a (Å)
b (Å)
c (Å)
14.4507(9)
14.2478(9)
20.7477(14)
90
99.3060(10)
90
4215.5(5)
2
1.409
11.502(3)
12.890(4)
13.181(4)
72.899(4)
69.611(4)
79.190(4)
1742.9(9)
2
a
(°)
b (°)
c
(°)
V (Å3)
Z
Dcalc (g cmꢀ3
F(0 0 0)
Scan mode
)
1.367
732
x
1832
x
h Range for data collection (°)
Ranges of h, k, l
1.60, 26.04
1.66, 26.08
ꢀ17 6 h 6 14, ꢀ17 6 k 6 17, ꢀ18 6 l 6 25
23 355/8323 [Rint = 0.0609]
5104
ꢀ14 6 h 6 14, ꢀ15 6 k 6 15, ꢀ11 6 l 6 16
9816/6708 [Rint = 0.0183]
5621
Reflections collected/unique
Independent Reflections
Absorption coefficient (mmꢀ1
)
1.225
0.771
Final R induces [I > 2
R indices (all data)
r
(I)]
R1 = 0.0527, wR2 = 0.1050
R1 = 0.0941, wR2 = 0.1211
0.935
Semi-empirical from equivalents
Full-matrix least-squares on F2
8323/6/451
R1 = 0.0382, wR2 = 0.0822
R1 = 0.0492, wR2 = 0.0878
1.021
Semi-empirical from equivalents
Full-matrix least-squares on F2
6708/0/424
Goodness-of-fit on F2
Absorption correction
Refinement method
Data/restraints/parameters
Largest difference peak and hole (e Åꢀ3
)
0.983 and ꢀ0.660
0.636 and ꢀ0.255

X. Wu et al. / Journal of Organometallic Chemistry 694 (2009) 2981–2986
2983
2.4.2. Synthesis of HL
aluminium chloride, Scheme 1. Complexes 1 and 2 were prepared
by azeotropic removal of H2O from the reaction (in benzene) of di-
n-butyltin oxide and triphenyltin hydroxide with HL in a molar ra-
tio of 1:1, respectively, Scheme 2.
9,10-Dihydroanthracene-9,10-a,b-butanedioic anhydride (5.526 g,
0.02 mol), anhydrous aluminium chloride (5.334 g, 0.04 mol) and
dry toluene (11.057 g, 0.12 mol) were added into a three-neck
flask. The reaction mixture was stirred for 4 h at 50 °C, then poured
into a beaker. After hydrolyzation with cooled aqueous HCl (20%), a
brownish solid was precipitated, which collected by filtration.
Then the solid was dissolved by aqueous NaOH (10%), and the sur-
plus toluene was removed by hydrodistillation. The distilled fluid
was acidified by 10% HCl, and the crude product was precipitated,
then collected by filtration and washed with water. The pure prod-
uct was obtained by recrystallization from ethanol as a white pow-
der. Yield: 87.65%, m.p. 244–246 °C. Anal. Calc. for C25H20O3
(368.425 g molꢀ1): C, 81.50; H, 5.47. Found: C, 81.48; H, 5.46%. IR
3.2. IR spectra
Comparing the IR spectra of the free ligand HL with complexes 1
and 2, the bands at 3100–3550 cmꢀ1 which appear in the spectra of
the free ligand as the
plexes, thus indicating metal–ligand bond formation through these
sites. It is generally believed that the different values in be-
tween asymmetric ( as(COO)) and symmetric ( sym(COO)) absorp-
m(O–H) vibration, are absent in those of com-
D
m
m
m
tion frequencies can distinguish the ligating mode of
a
(KBr, cmꢀ1):
m(O–HꢂꢂꢂO) 3440;
m
as(COO) 1715, 1680;
m
sym(COO)
carboxylate moiety, that is, the value smaller than 200 cmꢀ1 indi-
cates that the carboxylate moiety is bidentate, while the value lar-
ger than 200 cmꢀ1 indicates that the carboxylate moiety is
1460, 1415; 1H NMR (CDCl3, ppm): 2.34 (s, 3H, –CH3), 3.38 (t,
1H, –CHCOOH, J = 4.8), 3.85 (t, 1H, –CH–COC6H4–, J = 3.2), 4.23 (d,
1H, –CH–, J = 5.6), 4.45 (d, 1H, –CH–, J = 5.2) 7.14–7.83 (m, 12H,
Ar–H), 11.65 (s, 1H, –COOH).
unidentate [29,30]. The mas(COO) and msym(COO) bands appear at
1615 and 1385 cmꢀ1 for complex 1 and 1665 and 1395 cmꢀ1 for
complex 2, respectively. The differences between these frequen-
2.4.3. Synthesis of complex [(n-Bu2Sn)4(L)2O2(OC2H5)2] (1)
cies,
D
[
m
as(COO)ꢀ
msym(COO)] are close to that found for monoden-
To a suspension of di-n-butyltin (0.249 g, 1 mmol) in dry ben-
zene (30 ml) was added HL (0.368 g, 1 mmol). The mixture was
heated under reflux for 8 h in a Dean–Stark apparatus for azeotro-
pic removal of the water formed in the reaction. After cooling
down to room temperature, the solution was filtered and the sol-
vent of the filtrate was gradually removed by evaporation under
vacuum until solid product was obtained. The solid was then
recrystallized from ethanol to give colorless crystals of complex
1. Yield: 58.6%, m.p. 197–198 °C. Anal. Calc. for C86H120O10Sn4
(1788.71 g molꢀ1): C, 57.75; H, H, 6.76; Sn, 26.55. Found: C,
tate carboxylato groups (230 cmꢀ1 for 1 and 270 cmꢀ1 for 2). This
is totally consistent with the X-ray structures. The band at 486 and
425 cmꢀ1 for 1 can be assigned to the
m
(Sn–O–Sn) mode [31–33].
The absorption band at 544 and 535 cmꢀ1 for 1 and 2 are attribute
to (Sn–C) stretching modes, respectively [30,12].
m
3.3. 1H NMR spectra
The 1H NMR spectra of the complexes 1 and 2 are given in Sec-
tion 2. In the 1H NMR spectra of ligand HL, the COOH group reso-
nance appear at 11–12 ppm. Whereas this resonance disappear
when the carboxylato group participated in coordination to the
Sn atoms in complexes. The n-butyl protons in 1 show a multiple
resonance due to –CH2–CH2–CH2– skeleton in the range of 1.32–
1.38 ppm and clear triple due to the terminal methyl groups at
0.86 ppm. While for 2, the phenyl protons show a multiple in the
region 6.9–7.9 ppm.
57.73; H, 6.79; Sn, 26.58%. IR (KBr, cmꢀ1):
2869; as(COO) 1615, sym(COO) 1385; (Sn–O–Sn) 486, 425;
(Sn–C) 544 cmꢀ1 1H NMR (CDCl3, ppm): 0.86 (t, 24H, J = 6.8,
m(C–H) 2956, 2927,
m
m
m
m
.
–CH3); 1.1 (t, 6H, J = 5.7, –OCH2CH3); 1.32–1.38 (m, 48H,
SnCH2CH2CH2–); 2.38 (s, 6H, Ar–CH3); 3.34 (t, 2H, –CH–COO–,
J = 2.2); 3.57 (m, 4H, –O–CH2–Me); 4.26–4.29 (t, 2H, –CH–
COC6H4Me, J = 2.1); 4.52 (d, 2H, –CH–, J = 2.2); 4.83 (d, 2H, –CH–,
J = 2.3); 6.9–7.9 (m, 24H, Ar–H).
3.4. Crystal structure
2.4.4. Synthesis of complex [(C6H5)3Sn(L)] (2)
To a suspension of Ph3SnOH (0.367 g, 1 mmol) in dry benzene
(30 ml) was added HL (0.368 g, 1 mmol). The mixture was heated
under reflux for 8 h in a Dean–Stark apparatus for azeotropic re-
moval of the water formed in the reaction. After cooling down to
room temperature, the solution was filtered and the solvent of
the filtrate was gradually removed by evaporation under vacuum
until solid product was obtained. The solid was then recrystallized
from ethanol to give colorless crystals of complex 2. Yield: 56.8%,
m.p. 118–120 °C. Anal. Calc. for C43H34O3Sn (717.44 gmolꢀ1): C,
71.99; H, 4.78; Sn, 16.55. Found: C, 71.96; H, 4.81; Sn, 16.53%. IR
3.4.1. [(n-Bu2Sn)4(L)2O2(OC2H5)2] (1)
The molecular structure of complex 1 is shown in Fig. 1, se-
lected bond distances and angels are listed in Table 2, The molecule
1 adopts a centrosymmetric dimeric structure by virtue of l3-oxo
[Sn(1)–O(1) 2.126(3) Å, Sn(1)–O(1A) 2.045(3) Å] which form the
central R4Sn2O2 core with planar Sn2O2 ring, resulting in a ladder
type structural motif. The two oxygen atoms of this unit are triden-
tate as they link three Sn atoms, two endo-cyclic and one exo-cyc-
(KBr,cmꢀ1):
1395; (Sn–C) 535,
m
(C–H) 2965, 2915, 2871; as(COO) 1665;
m
msym(COO)
m
m
(Sn–O) 235 cmꢀ1 1H NMR (CDCl3, ppm):
;
2.41 (s, 3H, Ar–CH3); 3.35 (t, 1H, –CH–COO–, J = 2.2); 4.45 (t, 1H,
–CH–COC6H4Me, J = 2.1); 4.52 (d, 1H, –CH–, J = 2.2); 4.83 (d, 1H,
–CH–, J = 2.3); 6.9–7.9 (m, 24H, Ar–H).
3. Result and discussion
3.1. Synthetic aspects
9,10-Dihydroanthracene-9,10-a,b-butanedioic anhydride was
prepared according to Diels–Alder reaction of the anthracene and
maleic anhydride. Ligand HL was synthesized according to Fri-
edel-Crafts acylation from 9,10-dihydroanthracene-9,10-
a,b-but-
anedioic anhydride and dry toluene in the presence of anhydrous
Scheme 1. The reaction scheme for synthesis of HL.

2984
X. Wu et al. / Journal of Organometallic Chemistry 694 (2009) 2981–2986
Scheme 2. The reaction scheme for synthesis of 1 and 2.
Fig. 1. Perspective view of 1 showing the atomic numbering scheme.
lic. The additional links between the endo- and exo-cyclic Sn are
provided by bidentate deprotonated ethanol that form the asym-
metrical bridges [Sn(1)–O(5) 2.134(4) Å and Sn(2A)–O(5)
2.263(4) Å]. Each exo-cyclic Sn atom is also coordinated by a mono-
dentate carboxylato ligand (Sn(2)–O(2) 2.177(4) Å). The Sn(2)–
O(3) distance 2.829 Å is considered long for primary Sn–O bonding,
but represent a type of secondary interaction [34]. The bond angles
are O(1A)–Sn(1)–O(1) 73.47(16)° and Sn(1A)–O(1)–Sn(1)
defined by the C(71), C(101) and O(1) atoms and the axial positions
are occupied by the O(2) and O(5A) and the angle of O(2)–Sn(2)–
O(5A) is 153.49(15)°. Distortions from the ideal geometries may
be related to the close approach 2.829 Å of the O(3) atom to
Sn(2). The formation of the dimeric distannoxanes 1 represents
an example of ladder-type carboxylates in which the insertion of
l2-OC2H5 group occurs. Crystal structure of 1 features a l2-coordi-
nation of –OC2H5. This result can be interpreted in terms of donor
strength competition, in which the –OC2H5 groups show higher do-
nor capacity than the carboxylato group of the HL [34,35].
106.51(15)° at the
Sn(1)–O(5)–Sn(2A) 100.84(15)°, Sn(2A)–O(1A)–Sn(1) 113.08(15)°,
O(1A)–Sn(2A)–O(5) 71.86(14)° at the 2-OC2H5 group.
l3-O atom and O(1A)–Sn(1)–O(5) 74.18(14)°,
l
This configuration leads to five-coordinate tin centres, each
existing in a distorted trigonal bipyramidal geometry. The trigonal
plane about Sn(1) is defined by the C(61), C(81) and O(1A) atoms
with the axial positions being occupied by the O(1), O(5) [ O(1)–
Sn(1)–O(5) 147.63(14)°]. For the Sn(2) atom, the trigonal plane is
3.4.2. [(C6H5)3Sn(L)] (2)
The molecular structure of 2 is shown in Fig. 2, selected bond
distances and angels are listed in Table 3. Complex 2 crystallizes
in the triclinic space group P1 with one molecule in the asymmet-
ric unit. To a first approximation the Sn atom is four-coordinated,
ꢀ

X. Wu et al. / Journal of Organometallic Chemistry 694 (2009) 2981–2986
2985
Table 2
2.057(2) Å] of the HL ligand. The range of tetrahedral angles for
the molecule is 93.90(10)–117.68(10)°, with the narrow and wide
angles being ascribed to the influence of the non-coordinating O(2)
atom. The O(2) atom approaches the tin atom at a distance of
2.735 Å, which is significantly less than 3.68 Å, the sum of their
van der Waals radii for Sn and O atoms [36]. Although not consid-
ered to represent a significant bonding interaction, the influence of
the O(2) atom is such that it causes the expansion of the C(31)–
Sn(1)–O(1) angle [117.68(10)°] and the concomitant contraction
in the O(1)–Sn(1)–C(11) angle [93.90(10)°]. Support for the conclu-
sion that the O(2) atom does not form a significant interaction with
tin is found in the disparity in the C(1)–O(1) and C(1)–O(2) bond
distance of 1.305(4) and 1.214(4) Å respectively. The structure mo-
tif of complex 2 is one of the two major motif for compounds of the
general formula R0CO2SnR3 [37].
Selected bond lengths (Å) and bond angles (°) for complex 1.
Bond lengths
Sn(1)–O(1)#1
Sn(1)–C(81)
Sn(1)–O(1)
Sn(1)–O(5)
Sn(1)–C(61)
Sn(2)–O(1)
Sn(2)–C(71)
Sn(2)–C(101)
Sn(2)–O(2)
2.045(3)
2.110(6)
2.126(3)
2.134(4)
2.139(6)
2.019(4)
2.128(10)
2.135(7)
2.177(4)
Sn(2)–O(5)#1
O(1)–Sn(1)#1
O(2)–C(24)
O(4)–C(13)
O(3)–C(24)
O(5)–C(110)
O(5)–Sn(2)#1
C(17)–C(22)
C(11)–C(23)
2.263(4)
2.045(3)
1.286(7)
1.210(6)
1.219(7)
1.457(8)
2.263(4)
1.579(7)
1.562(8)
Bond angles
O(1)#1–Sn(1)–C(81)
O(1)#1–Sn(1)–O(1)
C(81)–Sn(1)–O(1)
O(1)#1–Sn(1)–O(5)
C(81)–Sn(1)–O(5)
O(1)–Sn(1)–O(5)
O(1)#1–Sn(1)–C(61)
C(81)–Sn(1)–C(61)
O(1)–Sn(1)–C(61)
O(5)–Sn(1)–C(61)
O(1)–Sn(2)–C(71)
O(1)–Sn(2)–C(101)
C(71)–Sn(2)–C(101)
O(1)–Sn(2)–O(2)
C(71)–Sn(2)–O(2)
C(101)–Sn(2)–O(2)
115.6(2)
73.47(16)
97.9(2)
74.18(14)
97.3(2)
147.63(14)
117.8(2)
126.6(3)
94.8(2)
O(1)–Sn(2)–O(5)#1
C(71)–Sn(2)–O(5)#1
C(101)–Sn(2)–O(5)#1
O(2)–Sn(2)–O(5)#1
Sn(2)–O(1)–Sn(1)#1
Sn(2)–O(1)–Sn(1)
Sn(1)#1–O(1)–Sn(1)
Sn(1)–O(5)–Sn(2)#1
O(3)–C(24)–O(2)
O(3)–C(24)–C(23)
C(24)–C(23)–C(17)
C(13)–C(17)–C(23)
C(21)–C(11)–C(23)
C(32)–C(11)–C(23)
C(15)–C(22)–C(17)
C(24)–O(2)–Sn(2)
71.86(14)
91.3(3)
91.9(2)
153.49(15)
113.08(15)
140.41(17)
106.51(15)
100.84(15)
123.1(5)
119.6(5)
115.0(4)
113.6(4)
106.0(4)
106.6(4)
105.5(4)
108.1(4)
4. Biological studies
4.1. Antibacterial activity
98.8(2)
117.5(3)
109.4(2)
131.5(4)
81.63(14)
100.7(3)
97.4(2)
The antibacterial activity was performed against one Gram po-
sitive (Bacillus subtilis) and another Gram negative (Escherichia coli)
bacteria, and the results are summarized in Table 4. In order to
compare the results obtained, the Imipinem is used as standard
drug [38]. The results indicated that both 1 and 2 show higher
activity than n-Bu2SnO against these two bacteria, but lower than
the standard drug. The results also showed that the activity of the
complexes against E. coli is better than against B. subtilis. The activ-
ity of these compounds against E. coli decreased in the order Imipi-
nem > 2 > 1 > n-Bu2SnO > CH3CH2OH and against B. subtilis
decreased in the order Imipinem > 1 > 2 > CH3CH2OH > n-Bu2SnO
under experimental conditions. In comparison with the reported
organotin carboxylates, the antibacterial activities of 1 and 2
against E. coli are more active than the nine organotin esters,
Me2SnL2, Me3SnL, n-Bu2SnL2, n-Bu3SnL, Ph3SnL, (PhCH2)2SnL2,
[(Me2SnL)2O]2, Et2SnL2 and n-Oct2SnL2, where, HL is (E)-3-(3-fluo-
rophenyl)-2-(4-chlorophenyl)-2-propenoic acid [39]. However, the
activities of 1 and 2 against B. subtilis are slight less active than the
nine reported compounds.
4.2. Antitumour activity
The results of cytostatic activity are summarized in Table 5. IC50
values of the complexes are expressed in lM, together with that of
cisplatin for comparison. Both complexes 1 and 2 showed a dose-
dependent antitumour effect toward the Hela cell line. At concen-
Fig. 2. Perspective view of 2 showing the atomic numbering scheme.
trations of 10
lg/l, they provided 90% growth inhibition for 1 and
92% for 2, and the IC50 in vitro values is 1.4 and 1.2
lg/ml for 1
Table 3
and 2, respectively. Complexes 1 and 2 present lower IC50 values
than those of cisplatin (IC50 = 3.50) [40], which indicates their high
activity against the tumoral cell lines evaluated. The activity of the
complexes against the Hela cell line decreased in the order
2 > 1 > n-Bu2SnO. The results further demonstrated that triorgano-
tin(IV) compounds show better antitumour activity than diorgano-
Selected bond lengths (Å) and bond angles (°) for complex 2.
Bond lengths
Sn(1)–O(1)
Sn(1)–C(11)
Sn(1)–C(21)
Sn(1)–C(31)
O(1)–C(1)
2.057(2)
2.128(3)
2.117(3)
2.117(3)
1.305(4)
O(2)–C(1)
O(3)–C(47)
C(1)–C(2)
C(2)–C(3)
C(2)–C(5)
1.214(4)
1.209(4)
1.515(4)
1.538(4)
1.559(4)
Bond angles
Table 4
O(1)–Sn(1)–C(21)
O(1)–Sn(1)–C(31)
C(21)–Sn(1)–C(31)
O(1)–Sn(1)–C(11)
C(21)–Sn(1)–C(11)
C(31)–Sn(1)–C(11)
C(1)–O(1)–Sn(1)
108.05(10)
117.68(10)
114.12(12)
93.90(10)
111.68(12)
109.71(12)
108.40(18)
O(2)–C(1)–O(1)
O(2)–C(1)–C(2)
O(1)–C(1)–C(2)
C(1)–C(2)–C(3)
C(1)–C(2)–C(5)
C(3)–C(2)–C(5)
120.9(3)
123.6(3)
115.5(3)
111.9(2)
112.5(2)
110.1(2)
Antibacterial screening results of 1 and 2.
Compound
Dose (
l
g mlꢀ1
)
Antimicrobial circle diameter (mm)
Gꢀ
G+
CH3CH2OH
n-Bu2SnO
1
2
20
20
20
20
20
2.0
4.6
1.5
0
15.6
18.3
30
9.2
9.0
31
Imipinem [38]
existing in a distorted tetrahedral geometry defined by three ipso-
C atoms of the phenyl groups and the O(1) atom [Sn(1)–O(1)
Concentration used: 1000 lg/ml in ethanol.

2986
X. Wu et al. / Journal of Organometallic Chemistry 694 (2009) 2981–2986
Table 5
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Acknowledgements
We acknowledged the Project (20873181) supported by the
NSFC and the Project (2007AA06Z214) supported by the high-tech
Research and Development Programm of China; Project is
(ts20070704) supported by Taishan Scholars Construction
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Appendix A. Supplementary material
CCDC 706614 and 706814 contain the supplementary crystallo-
graphic data for complexes 1 and 2. These data can be obtained
free of charge from The Cambridge Crystallographic Data Centre
via www.ccdc.cam.ac.uk/data_request/cif. Supplementary data
associated with this article can be found, in the online version, at
doi:10.1016/j.jorganchem.2009.04.040.
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