Synthesis and structure elucidation of new series of organotin(IV) esters with bio-screening activity and catalytic study

Article abstract of DOI:10.1016/j.inoche.2010.09.015

A new series of fourteen numbers of organotin(IV) esters with NNDEG and NNDBG is being described. On the basis of IR, ¹H-, ¹³C-NMR, Mass and M?ssbauer spectroscopic studies and elemental analysis data, an interesting sinusoidal view of dimeric organotin(IV) is proposed and octahedral geometry is suggested for monomeric organotin(IV) esters while triorganotin(IV) complexes are assigned trigonal bipyramidal and tetrahedral geometry which is confirmed by ¹H NMR. All the OTCs except 1, 4, 8 and 10 exhibited excellent rate of mortality against selected insects. OTCs (2, 6, 9, and 11) at 500 ppm showed a two-fold positive role than standard drug Enoxacin as an antibiotic against the selected bacterial strains. ED₅₀ of all OTCs is also reported here. The catalysis study of monomeric OTCs give 80% yield while dimeric OTCs give 100% yield of benzylacetate in six hours of reaction time.

Full text of DOI:10.1016/j.inoche.2010.09.015

Inorganic Chemistry Communications 14 (2011) 5–12
Contents lists available at ScienceDirect
Inorganic Chemistry Communications
journal homepage: www.elsevier.com/locate/inoche
Synthesis and structure elucidation of new series of organotin(IV) esters with
bio-screening activity and catalytic study
a
a
b
a
Muhammad Ashfaq a, , M. Mahboob Ahmed , Salma Shaheen , Hiroyuki Oku , Karamat Mehmood ,
⁎
Abdullah Khan c, Shahida Begum Niazi d, Tariq Mahmood Ansari d, Abdul Jabbar e, M.I. Khan f
Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur, Pakistan
a
b
Department of Chemistry and Chemical Biology, Gunma University, Japan
Department of Chemistry, University of Baluchistan, Quetta, Pakistan
Department of Chemistry, B.Z. University Multan, Pakistan
Department of Chemistry, G.C. University, Faisalabad, Pakistan
c
d
e
f
Department of Chemistry, Kohat University of Science and Technology, NWFP Pakistan
a r t i c l e i n f o
a b s t r a c t
Article history:
A new series of fourteen numbers of organotin(IV) esters with NNDEG and NNDBG is being described. On the
basis of IR, 1H-, 13C-NMR, Mass and Mössbauer spectroscopic studies and elemental analysis data, an
interesting sinusoidal view of dimeric organotin(IV) is proposed and octahedral geometry is suggested for
monomeric organotin(IV) esters while triorganotin(IV) complexes are assigned trigonal bipyramidal and
tetrahedral geometry which is confirmed by 1H NMR. All the OTCs except 1, 4, 8 and 10 exhibited excellent
rate of mortality against selected insects. OTCs (2, 6, 9, and 11) at 500 ppm showed a two-fold positive role
than standard drug Enoxacin as an antibiotic against the selected bacterial strains. ED50 of all OTCs is also
reported here. The catalysis study of monomeric OTCs give 80% yield while dimeric OTCs give 100% yield of
benzylacetate in six hours of reaction time.
Received 14 August 2010
Accepted 15 September 2010
Available online 19 September 2010
Keywords:
NN-diethylglycine (NNDEG)
NN-dibutylglycine (NNDBG)
Organotin compounds (OTCs)
Tri Organotin compounds (TOTCs)
© 2010 Elsevier B.V. All rights reserved.
Organotin(IV) complexes of amino acids and their derivatives with
four and more than four coordination number display significant role
in several fields like fungicides, pesticides, anti-fouling coating
materials, polymer stabilizers and wood preservatives etc [1–12].
The role of amino acids and their derivatives with antioxidant
property and good immune response to flu and salmonella is
reported, which enhance cellular and hormonal immunity, help to
transport oxygen into cells as well prevent lactic acid level and faster
muscle growth. The glycine is also a neurotransmitter in the central
nervous system, a novel antioxidant and important in manufacturing
of hormones responsible for a strong immune system [5]. The ligands
NN-diethylglycine and NN-dibutylglycine (Scheme 1) selected due to
potential of glycine. The organotin(IV) esters have proven themselves
more promising in character [5–7]. This is an extension of our
previous work based on bioactivity and structural chemistry of
organotin(IV) complexes [8–13].
particularly in patients with severe burns, in cancer and AIDS patients.
The E. coli causes food borne illness and bloody diarrhea etc. S. typhi
causes headache anorexia rose spots splenomegaly fever, malaise,
weight loss, disseminated intravascular coagulation, bacteremia, chills,
abdominal pain, weakness and hepatomegaly. K. pneumoniae causes
pain on urination, dysuria urgent urination, suprapubic pain, back pain,
pus, erythema and suppuration inflammation etc [14]. While the rate of
toxicity was determined against Tribolium castaneum (red flour beetle),
mealybug in cotton and Monomorium minimum (black ant) insects since
red flour beetle and black ant damage millions of tons of corn food per
year. Red flour beetles attack stored grains products (flour, cereals,
pasta, biscuits) beans, nuts etc. causing loss and damage. The mealybug
lethally inhibits cotton plant growth. According to statistics in Pakistan,
in the fiscal year 2007–2008, 40–45% cotton areas in Pakistan were
affected and 3.5 million bales of cotton were reduced than the previous
year [15]. An ED50 (effective dose) test against brine shrimp larvae was
also performed. On the other hand OTCs are well established as
homogenous catalysts in various transesterification or transcarbamoy-
lation processes. The acetyl ester plays an important role for protection
of the hydroxyl group in organic synthesis [15]. The catalytic activity of
monomers as well as dimers is being reported.
In the present study, Pseudomonas aeruginosa, Klebsiella pneumoniae,
Salmonella typhi and Escherichia coli bacterial strains were tested to
evaluate potential of prepared compounds. The P. aeruginosa destroys
host defense system. It causes infection in urinary, respiratory system,
soft tissue, bone and joint, gastrointestinal and variety of other system,
In this study complexes 1–14 derived from (C2H5)2NCH2COOH and
(C4H9)2NCH2COOH (Scheme 1) are non hygroscopic, quite stable at
room temperature. As per reported in literature [4,8–10,16–20], the
ligands NNDEG and NNDBG and their organotin(IV) complexes were
⁎
Corresponding author. Tel.: +92 300 682 9307.
E-mail address: chashfaqiub@yahoo.com (M. Ashfaq).
1387-7003/$ – see front matter © 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.inoche.2010.09.015

6
M. Ashfaq et al. / Inorganic Chemistry Communications 14 (2011) 5–12
a
b
6
5
4
4
3
3
O
O
N
N
1
1
HO
HO
2
2
Scheme 1. (a) NN-diethylglycine. (b) NN-dibutylglycine.
synthesized by taking appropriate molar amount of dibutyltin(IV)
oxide in ratio (1:1 and 2:1) with respect to ligands in ethanol and
toluene, in case of triorganotin(IV) complexes, the silver salts of
ligands and organotin(IV) chloride in chloroform were refluxed for 5–
6 h. The solvent was removed under vacuum. The crystalline or
amorphous material was obtained with a series of ligands and
recrystallized in chloroform and ethanol (Scheme 2).
compared to ligands can be arranged like νasym (complex) bνasym (ligand),
νsym (complex) bνsym (ligand), Δν (complex) NΔν (ligand) . The experimental
data of 1–14 complexes is given in Ref. [22]. The mass spectrum of
organotin(IV) compounds did not show prominent molecular ion
peak while only molecular ion peaks of NNDEG and NNDGB were
observed during mass analysis. Mass spectra of ligands NNDBG and
NNDEG were easily patronized into fragments with prominent
molecular ion at m/z 187 and 131.09 respectively. The pattern of
fragmentation according to mass spectra is given in Schemes 3 and 4.
The 1H NMR of monomeric (1,8) and dimeric compounds (2, 9)
were recorded at 30 °C temperature and found to be shifted on proper
positions while endo- and exocyclic Sn(IV) centers were difficult to
identify as reported in literature [8–10,19]. Specifically, the spectrum
of compound 1 is given in Fig. 1 while other compounds showed
similar behavior.
The elemental analysis of C, H, N data was in agreement with the
predicted formula and complexes 1–14 gave sharp melting points
which indicate the isolation of fairly pure complexes. The IR data are
consistent with the formation of well-defined compounds with the
compositions. The carboxylate group of both ligands is able to
coordinate to metal ions by different modes of coordination, based
on the IR asymmetric and symmetric stretching of COO group and the
stretching for Sn–C and Sn–O. It was possible to differentiate in mode
of bonding with Sn(IV) atom as reported in the literature [8,9,16–21].
Characteristic vibrational frequencies have been identified by com-
paring the spectra of all the complexes with their precursors, the
bands associated with the N-butyl moieties are in positions similar to
those they occupy as free ligands. The data are consistent with the
formation of well-defined complexes, which was confirmed by the
presence of Sn–O and Sn–C bonds in the range 713–738 cm−1 and
545–578 cm−1, respectively, the broad band of the OH group of free
ligands (3520–3140 cm−1) disappeared in the spectra of all the
complexes 1–14. The difference of Δν between the carboxylic group's
ν(COO)sym and ν(COO)asym gives interesting information about the
molecular arrangement in such complexes. The literature reveals
[8,12] that in complexes with a difference of Δνb200 cm−1, the
carboxylate group of such complexes can be considered to be
practically bidentate in a trans octahedral arrangement for the
monomer complexes 1 and 8 while dimer complexes (2 and 9)
were treated by similar bidentate bonding with endo and exo Sn(IV)
atoms, which suggested hexa coordination to tin(IV) in the dimer and
ranking of stretching of CO group of organotin(IV) compounds as
The 13C NMR of compounds exhibited sharp signals of each carbon
which distinguished between mono and dimeric nature of organotin
(IV) esters and spectrum of compound 1 is selected here as specimen
which is given in Fig. 2.
The 119Sn NMR chemical shift of monomeric type revealed
coordination from carboxylic oxygen to tin center, which suggested
the bidentate ligation with Sn(IV) in equatorial positions with two
adjacent short and two longer Sn–O bonds. The monomer compound
1 showed chemical shift at −184.50 ppm and dimer compound 2
showed two signals at −197.25 and −213.15 ppm as described in
literature [8,9,19]. Fig. 3 is given to describe the shifting of 119Sn nuclei
in compound 1. The spectral data is described in Ref. [22].
The quadrupole splitting value (QS=3.28 and 3.38 mm s−1) of
119mSn Mössbauer [23,24] for monomers recommended hexa coordi-
nate environment, which strongly suggested the octahedral geometry
as described in Fig. 4.
The 119Sn NMR spectrum of dimer OTC showed two signals at low
and high resonance. The exo tin(IV) atom may be bonded in
monodentate mode with carboxylic oxygen of ligand. However, the
Bu2SnO + 2 R/COOH
Bu2 Sn(OOCR)2 + H2 O
[cpd. 1,8]
4Bu2SnO + 4 R/COOH
[{Bu2 Sn(OOCR)}2 O]2 + 2H2O
(R/ COO)2Sn(C4H9)2 + 2AgCl
[cpd.2,9]
2R/COOH + R2SnCl2 + 2Ag NO3
R/COOH + R3SnCl +Ag NO3
[cpd. 4,11]
R/COOSnR3 + AgCl
[cpd, 3,5,6,7,10,12,13,14]
R/ = (C2H5)2NCH2 , (C4H9)2NCH2 -, Bu = Butyl
a
R
=
a
a
b
b
b
c
d
b
,
c
,
,
c
Bu =
d
c
a
e
d
d
Scheme 2. Synthesis of organotin(IV) esters.

M. Ashfaq et al. / Inorganic Chemistry Communications 14 (2011) 5–12
7
Scheme 3. Pattern of fragmentation of NNDBG.
endo cyclic tin(IV) atom may be bonded in bidentate mode with oxygen
of carboxylic groups of ligand as a result penta coordinate geometry is
already reported of dimeric stannane [10]. The dimeric might be
proposed in ladder topology and gave beautiful sinusoidal view from
one unit to others as shown in Fig. 5. Each exo and endo tin(IV) atom
displays six coordination number after ligation with other stannane
molecule. The 1H NMR spectra of dimer compounds 2 and 9 did not give
distinct butyl proton signals ligated to endo and exo tin(IV) atom, which
indicate the equal status exo and endo tin(IV) verifying a sinusoidal
view with the neighboring organotin centers being linked by one O-
atom of the carboxylate ligands. While as reported in [25] the butyl
protons exo and endo Sn in dimer exhibit two kinds of butyl's proton
signals when it existed in dimeric form but in the present study no
distinctive signal for exo and endo stannane bearing butyl could be seen
in 1H NMR spectra. It is obviously due to six coordination sites of each
endo and exo tin(IV) atom with chemically equivalent nature but in non
polymeric form both the endo and exo tin atoms are chemically non
equivalent, which can possibly be confirmed by X-ray diffraction which
is now under further investigation.
Mössbauer spectroscopy was carried out on some selected
complexes [23] all these spectra exhibit IS/δ and all spectra contained
a well-defined doublet which clearly indicate the presence of Sn(IV)
Scheme 4. Pattern of fragmentation of NNDEG.

8
M. Ashfaq et al. / Inorganic Chemistry Communications 14 (2011) 5–12
Fig. 1. 1H NMR spectra of compound 1.
species. The δ values of 2.30–2.61 agree with the value (δ=2.36)
reported in literature [26,27]. Specifically compounds 2 and 9 bear
equivalent environment for the endo and exo Sn(IV) moieties which
suggests sinusoidal structure as proposed in Fig. 5. In the case of the
third type of compounds triorganotin(IV) compounds (TOTCs), the IR
behavior of carbonyl (CO) is found the same as reported in literature
[9,24,28–30]. The large asymmetric and small symmetric stretching
data of compounds than ligand while Δν in the complexes was also
larger than the Δν of ligand, which recommended unidentate or weak
bidentate bonding to tin(IV) [22,31,32], which may easily be
identified by stretching ranking of CO between complexes and ligands
Fig. 3. 119Sn NMR spectra of compound 1.
Bu
R
R
O
O
O
O
N
R
R
N
[νasym (OTCs) bνasym
νsym (OTCs) bνsym
Δ ν (OTCs) NΔ ν
Sn
(ligand),
(ligand),
(ligand)]. The 1H, 13C and 119Sn NMR multiplicity and intensity pattern
of TOTCs as reported elsewhere [3,8,9,30–33] recommended tetrahe-
dral geometry as reported previously. The 119Sn NMR signals were
seen over the range as reported for triphenyl, tribenzyl, tributyl and
the tricyclohexyl moieties ligated to Sn(IV) is an indication of penta
coordinate environment led to a polymeric trigonal bipyramidal in the
solid and a tetrahedral geometry in an inert solvent for triphenyltin
(IV) ester while tricyclohexyltin(IV) compound exhibited tetrahedral
geometry [30,31]. According to literature [33–39], the compounds
with 119Sn NMR values in the range of −120 to −155 ppm have a
five-coordinate chain polymeric structure and the complexes with
119Sn NMR~70 to 80 ppm range displayed a tetrahedral in solid and
trigonal bipyramidal geometry with a bridging carboxyl group in an
inert solvent [9,31].
Bu
Fig. 4. Octahedral geometry of a monomer.
the help of sterilized loop and spread it on the culture medium and
incubated at 37 °C. After 24 h the bacterial colonies were identified
under microscope. Then solutions 200 ppm, and 500 ppm of ligands
and corresponding OTCs were prepared in methanol. The sterilized
discs were soaked in test solutions and dried marked as pregnant disc.
The microbial sample was seeded on the sensitivity medium petri
plates and incubated at 37 °C. The pregnant discs were fixed as the
standard and inhibition zones were measured after 24 h. ED50 was
Besides of the synthesis and characterization of the synthesized
compounds, antibiotic, ED50, and toxicity of compounds was also
being determined. The glassware such as petri plates, conical flasks
and test tubes were sterilized at 150 °C for 20 min before use. The
microbial samples were taken from the Pathological Department of
Quaid-e-Azam Medical College Bahawalpur, which were received
from various wards of the Bahawal Victoria Hospital (BVH) of
Bahawalpur. These samples were collected as swabs of pus, blood,
urine, sputum, semen etc. Four bacterial strains (E. coli, P. aeruginosa,
K. pneumoniae and S. typhi) were selected for antibacterial activity.
MacConkey agar and C.L.E.D mediums 10 g were dissolved in 250 mL
distilled water under heat and autoclaved. The petri plates were
prepared and incubated over night. Microbial sample was taken with
determined against
a brine shrimp hatching method [40].
M. minimum, mealybug of cotton plant and flour beetle insects were
selected to check the % toxicity rate. Experimental treatments
containing 0.01% w/w of compounds and flour and the control
treatments contained only 100% flour as a nutrient. The ten numbers
of insects were kept in the experimental and control treatments. The
data taken in the form of dead and live insects was used to determine
% toxicity of OTCs. The dimeric OTCs and TOTCs showed very good
response against bacterial strains. The experimental data is given in
the Table 1. The dimer and TOTCs showed excellent activity against
E. coli only at 500 ppm, which was two folds greater than the standard
Fig. 2. 13C NMR spectra of compound 1.

M. Ashfaq et al. / Inorganic Chemistry Communications 14 (2011) 5–12
9
Fig. 5. Sinusoidal view of a dimer.
Table 1
Antibiotic bioassay.
Bacterial strains
Activity of OTCs (at doze 500 ppm)
NNDEG
NNDBG
2
4
5
6
7
9
10
11
12
13
14
Escherichia coli
++
++
++
++
++
++
++
++
++++
++++
++++
++++
++
++
++
++
+++
–
++++
++++
++++
++++
++
–
++++
++++
++++
++++
+
++
+
++++
++++
++++
++++
++
++
++
++
++
++
++
++
++
Pseudomonas aeruginosa
Klebsiella pneumoniae
Salmonella typhi
++++
+++
++++
+++
+++
++
++
–
Where: ++++=more significant, +++,=significant, ++=less significant, – =no activity.
Antibiotic Enoxacine=standard with 1000 ppm doze.
(1000 ppm). The compounds 2, 6, 9 11 and 13 also gave good rate of
activity at 500 ppm concentration while ligands (NNDEG and NNDBG)
showed very low potential. Two selected experimental petri plates of
microbes can be seen in Fig. 6 and results are in Table 1.
In vitro LD50 (Lethal dose) test was carried against the insects
using Probit analysis procedure (Table 2) .All the TOTCs showed
excellent rate of mortality against M. minimum and T. castaneum
except of mealybug that was found insignificant. It may be due to
having penta coordinate environment and weak coordination of
carbonyl oxygen is easily available to inhibit the metallic enzymes in
metabolism of bacterial strains which lead to their mortality while at
the same time, Sn(IV) metal atom of complex provide more vacant
orbitals to coordinate with donor atoms like O, S and N of enzymes.
ED50 effective measurements of all compounds were carried out
against brine shrimp larvae using standard statistical procedure Probit
analysis (Table 3). Compound 1 and 8 monomers found to be inactive
and while dimers 2 and 9 are found to be effective. The ED50 values of
all other TOTCs esters fall in very narrow range of 3.16 μg mL−1
showed highest effects as we have already reported [9]. Similarly the
TOTCs act to inhibit the metallic enzymes of naupli and this class is
significantly active than other classes since having a greater partition
coefficient value [18]. It may also be considered the presence of lone
Fig. 6. Antibiotic activities against E. coli.

10
M. Ashfaq et al. / Inorganic Chemistry Communications 14 (2011) 5–12
Table 2
Toxicity bioassay.
Cpds. no.
% Death
Monomorium minimum
Dose (μgmL−1
% Death
% Death
Tribolium castaneum
Mealybug in cotton plant
)
Dose (μgmL−1
)
Dose (μgmL−1
)
1000
100
10
*LD50
Results
1000
100
10
*LD50
Results
1000
100
10
*LD50
Results
NNDEG
NNDBG
1
2
3
4
5
6
7
8
9
10
11
12
13
14
–
–
–
–
– – – – –
– – – –
– – – –
+++
++++
– – –
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
– – – –
– – – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
–
–
–
–
–
–
–
–
20
–
–
∞
20
90
80
–
–
–
∞
– – – –
++
++
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
100
100
90
100
100
100
30
100
100
100
100
100
100
80
90
60
80
90
70
–
50
60
40
40
70
50
–
19.95
10.00
39.81
50.11
3.60
3.98
∞
50
60
–
30
40
–
63.09
31.62
++
90
90
80
20
100
100
90
100
100
100
70
60
50
–
50
40
40
–
39.81
79.21
19.95
++
+
+++
–
++++
++++
–
90
100
80
90
100
80
80
70
70
40
70
60
7.07
5.01
17.78
14.12
5.01
10.00
++++
++++
+++
+++
++++
++++
70
80
80
50
100
60
50
60
50
30
90
40
25.12
15.85
12.59
31.62
5.62
+++
+++
+++
++
++++
+++
19.95
Note: i) 0.01% w/w of compounds and flour. ii) Control treatments contained 100% flour as nutrient showed no mortality.
Where: *=μg mL−1 ++++=more significant, +++=significant, ++=less significant and – – –=no activity.
pair on oxygen of carbonyl of ligand is not involved in the
coordination process, which may play a key role to increase their
activity. Similar role and mechanism is expected due to dimeric class
of OTCs. Moreover, toxicity is also confined with an attached R group
to tin(IV) atom. As it is found in literature that lipophillicity increases
with the bulkiness of R groups also increase the polarity of OTCs,
which enhances the partition coefficient, thereby increasing the
bioactivity [9]. In conclusion, that the bulkiness of the attached R
group and polar character of carboxylic groups ligands NNDBG or
NNDEG after ligation with tin(IV) are interlinked with each other,
which enhance the polarity and partition coefficients of the metal
complexes than the ligands themselves. The NNDBG as well NNDEG
did not exhibit promising activity during study. In addition the R3SnL
unit, the ligand (L) plays a key role in transporting the active site of
organotin(IV) moiety [1–6,40–42]. Among such compounds, the
carboxylate derivatives are used as anticancer and anti-tumor agents
in vivo as well as in vitro fungicides or bactericides [42–46]. The
biocide activity of triorganotin(IV) motifs is enhanced on account of
their geometry in solution. The tetrahedral structure in solution is
more active than other forms even [47,48] that the four coordinated
species have stronger tendency to increase the coordination numbers
by O, S, or N donor groups. While the six coordinate species do not
undergo further coordination which plays no long term role in vivo
chemistry of organotin(IV) esters. Their catalytic activity is attributed
to weakly coordinating ability of anions, which leads to enhanced
Lewis acidic nature of the organotin(IV) moiety. The catalytic activity
of 1, 2, 8 and 9 were assessed for acetylation of benzyl alcohol by
ethylacetate, which is communicated here. Ethylacetate was used as
solvent, while the molar ratio of catalyst:substrate was 1:100. The
reaction mixture was refluxed at 70 °C for 1 to 10 h. Under these
conditions, the acetylation catalyzed by monomers and dimers was
normally progressed and quantitative yields were obtained after 6 h
by gravimetric method. When the monomeric catalysts 1 and 8 were
used and 80% yield was obtained within 6 h. However, dimeric
catalysts 2 and 9 were able to give quantitative 100% yields after 6 h
(Table 4). Benzyl alcohol (1 mM) was slowly added to a solution of
Table 3
ED50 bioassay.a
Compounds
% Deaths at doses
ED50 μg mL−1
Results
1000 μg mL−1
100 μg mL−1
10 μg mL−1
NNDEG
NNDBG
1
2
3
4
5
6
7
8
9
10
11
12
13
14
10
20
30
90
90
–
–
∞
– – – –
– – – –
– – – –
++++
+++
–
–
∞
10
70
60
60
70
80
80
20
90
80
70
90
100
90
10
60
40
30
50
70
70
10
80
50
60
70
80
90
∞
10.00
31.61
50.12
14.13
19.95
3.16
∞
80
– – – –
100
100
90
+++
+++
++++
– – – –
++++
+++
40
100
100
100
100
100
100
3.55
12.59
15.85
10.00
3.16
4.48
+++
++++
++++
++++
a
Brine shrimps were under test, Where: ++++=more significant, +++=significant – – – –=no activity.

M. Ashfaq et al. / Inorganic Chemistry Communications 14 (2011) 5–12
11
[9] M. Ashfaq, A. Majeed, A. Rauf, A.W.K. Khanzada, W.U. Shah, M.I. Ansari, Bull. Chem.
Soc. Jpn 72 (9) (1999) 2073.
[10] M. Ashfaq, J. Organomet. Chem. 691 (2006) 1803.
Table 4
Acetylation of benzyl alcohol catalyzed by mono and dimeric OTCs.
[11] M.I. Khan, M.K. Baloch, M. Ashfaq, J. Organomet. Chem. 689 (2004) 3370.
[12] M.I. Khan, M.K. Baloch, M. Ashfaq, Obaidullah, Appl. Organomet. Chem. 20 (2006)
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[13] M. Pervez, S. Anwar, A. Badshah, B. Ahmad, A. Majeed, M. Ashfaq, Acta Cryst. C 56
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[14] [a] T.C. Eickhoff, Klebsiella pneumoniae infection”, a review with reference to the
water borne epidemiologic significance of K. pneumoniae presence in the
natural environment, National Council of the Paper Industry for Air and
Stream Improvement, Inc. Technical Bulletin No. 254, 1972, New York, N.Y.;
[b] W.J. Martin, P.K.W. Yu, J.A. Washington, Epidemiological significance of
Klebsiella pneumoniae, Mayo Clin. Proc. 46 (1971) 785;
[c] R. Selden, S. Lee, W.L.L. Wang, J.V. Bennett, T.C. Eickhoff, Ann. Intern. Med. 74
(349) (1971) 657.
[15] [a] P.G. Fields, Y.S. Xie, X. Hou, J. Stored Prod. Res. 37 (2001) 359;
[b] K.A. Gomez, A.A. Gomez, Statistical procedures for agricultural research, 2nd
ed, JohnWiley and Sons, New York, 1984, p. 680;
[c] X.W. Hou, P.G. Fields, J. Econ. Entomol. 96 (2003) 1005;
[d] J. Otera, Chem. Rev. 93 (1993) 1449.
[16] [a] K. Sisido, Y. Takeda, Z. Kinugawa, J. Am. Chem. Soc. 83 (3) (1961) 538;
[b] K. Hans, M. Pervez, M. Ashfaq, S. Anwar, A. Badshah, A. Majeed, Acta
Crystallographica E58 (2002) m466.
Cpd. no. (conc)/mol%
Reaction time(h)
% yield
1
2
8
9
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
1
3
6
10
1
3
6
10
1
3
6
10
1
3
6
10
25
61
80
80
30
g
g
g
g
82
100
100
26
63
80
80
31
81
100
100
[17] [a] R.E. Bowman, J. Chem. Soc. (1950) 1346;
[b] K.C. Molloy, T.G. Purcell, K. Quill, I.W. Nowell, J. Organomet. Chem. (1984)
267.
[18] C.C. Camacho, Vos de Dick, B. Mahieu, M. Gielen, M. Kemmer, M. Biesemans, R.
Willem, J. Organomet. Chem. 3 (1999) 381.
[19] M. Gielen, A. Bouhdid, R. Willem, V.I. Bregadze, L.V. Ermanson, E.R.T. Tiekink,
J. Organomet. Chem. 50 (1995) 277.
[20] B. Jousseaume, V. Guillou, N. Noiret, M. Pereyre, J.M. France, J. Organomet. Chem.
450 (1993) 97.
ethylacetate (5 ml). Catalytic reaction was started by adding 10 μM of
1 or 2 or 8 or 9 OTCs. The ratio of catalyst:benzyl alcohol was 1:100.
The reaction mixture was refluxed at 70 °C and % yield of benzyl
acetate was measured gravimetrically after 1, 3, 6 and 10 h of reaction
proceedings. The reaction was also checked without catalyst but no
significant yield was obtained. The catalytic findings are in accordance
to a previously proposed mechanism [15], whereas the existence of an
active core (sinusoidal view Fig. 5) of dimeric distannoxane have a
vital role in acetylation of benzyl alcohol. Here transesterification
catalyzed by 2 and 9, which bears such distannoxane center as enough
active sites to catalyze benzyl alcohol and resulted in a 100% yield
within 6 h. The reaction catalyzed by monomeric catalysts 1 and
8 slowed down on account of no such enough active sites are provided
(Fig. 4) as that of provided by the distannoxane core.
[21] W.J. Xiaohong, L. Rongchang, Z. Bin, Li. Jingfu, Main Group Met. Chem. 25 (2002)
535.
[22] Ligands “NN-diethylglycine (NNDEG) (m.p 132 °C), IR analysis (cm−1): OH:
3500–3140, CO(carbonyl): 1665asym 1549sym , Δν: 117 and NN-dibutylglycine
(NNDBG) (m.p 134–135 °C, IR analysis (cm−1): OH: 3520–3130, CO(carbonyl):
1670asym 1556sym , Δν: 114 were prepared according to the reported procedure
using ethanol as a solvent [17]. The tribenzyltin(IV) chloride (m.p 130 °C) and
dibenzyltin(IV) dichloride (m.p 112 °C) were synthesized as reported elsewhere
[16]. Compound 1 DBTNNDEG (monomer), [(C2H5)2NCH2COO]2SnBu2 was re-
crystallized in chloroform and ethanol 1:2 ratio, mp: 67 °C, yield: 84%, solubility:
soluble in chloroform, ethanol and methanol. CHN analysis (%) antipyrene: C:
50.68 (50.69), N: 5.35 (5.37), H: 8.87 (8.89).IR analysis (cm−1): CO(carbonyl):
1645 asym 1525 sym sb, C_N: 1527 (b) CO (ether linkage):1040 (s) Δν: 120. Sn–C: 547
w.sp; Sn–O: 722 sp.1H NMR (CDCl3): H-2: 3.20 s; H-3: 2.59 q(7.1 Hz); H-4: 0.93 t
(7.1 Hz); H-a: 1.03 t(7.1 Hz);H-b: 1.65-1.71 m; H-c: 1.32-1.42 m; H-d: 0.91t(7.4 Hz)
(Fig. 1).13C NMR(CDCl3): C-1:171.91; C-2: 57.08; C-3: 47.95; C-4: 13.21; C-a: 27.81;
C-b: 28.24; C-c: 24.87; C-d: 13.05 (Fig. 2).119Sn NMR (CH3)4Sn: −184.50 (Fig. 3).
119mSn Mössbauer data (mm s−1): QS: 3.28; IS: 1.25; G1: 0.83; G2: 0.82; δ=QS/IS:
2.62.Compound
2 DBTNNDEG (dimer), [{(C2H5)2NCH2COOSnBu2}2O]2 was re-
Acknowledgements
crystallized in chloroform and ethanol 1:2, mp: 55 °C, yield: 86%, soluble in
chloroform, methanol and ethanol on heating.CHN analysis (%) antipyrene: C: 45.29
(45.31), N: 3.75 (3.77), H: 8.13 (8.15).IR analysis (cm−1): CO(carbonyl): 1659asym
1529sym sb, C_N: 1529 (b) CO (ether linkage):1043 (s) Δν: 120. Sn–C: 574 w.sp; Sn–
O: 713 sp.1H NMR (CDCl3): H-2: 3.21 s; H-3: 2.61 q(7.2 Hz); H-4: 0.95 t (7.2 Hz); H-
a:1.10; H-b:1.47q(7.2 Hz); H-c:1.22 hx(7.2 Hz); H-d:0.92 t(Hz).13C NMR(CDCl3): C-
1:172.01; C-2: 57.28; C-3: 48.01; C-4: 14.21; C-a: 28.11; C-b: 24.33; C-c: 25.41; C-d:
14.67.119mSn Mössbauer data (mm s−1): QS: 3.59; IS: 1.53; G1: 0.83; G2: 0.82; δ =
QS/IS: 2.34. 119Sn NMR (CH3)4Sn: −197.25, −213.15.Compound 3 TBzTNNDEG,
[(C6H4CH2)3SnOOCCH2N(C2H5)2] was re-crystallized in chloroform, mp: 97-101 °C,
yield: 75%, soluble in chloroform, ethanol and methanol, insoluble in other organic
solvents and water. When seven fold of water was added its alcoholic solution
remained clear.CHN analysis (%)antipyrene: C: 62.06 (62.09), N: 2.65 (2.68), H: 6.34
(6.37).IR analysis (cm−1): CO(carbonyl): 1655asym 1531sym sb, C_N: 1530 (b) CO
(ether linkage):1057 (s) Δν: 124, Sn–O: 723 sp, Sn–C: 555 w.sp.1H NMR (CDCl3): H-
2: 3.31 s; H-3: 2.62 q (7.1 Hz); H-4: 1.04 t (7.1); H-a: 2.71 s; H-c,- d,-e: 7.21–
7.34 m.13C NMR (CDCl3): C-1: 167.51; C-2: 56.64; C-3: 48.77; C-4: 11.19; C-a: 20.71;
C-b: 136.51; C-c: 128.44; C-d: 127.43; C-e: 124.57.119Sn NMR (CH3)4Sn: −143.55.
Compound 4 DBzTNNDEG, [(C6H4CH2)2Sn{OOCCH2N(C2H5)2}2] was solidified in
chloroform, mp: 199–202 °C, yield: 71%, soluble in chloroform, ethanol and
methanol, DMSO insoluble in other organic solvents and water. When eight fold of
water was added its alcoholic solution remained clear.CHN analysis (%)antipyrene:
C: 55.61 (55.63, N: 4.97 (4.99), H: 6.79 (6.82).IR analysis (cm−1): CO(carbonyl):
1667asym, 1547sym sb, C_N: 1532 (b) CO (ether linkage):1041 (s) Δν: 120, Sn–O:
737 sp, Sn–C: 566 w.sp.1H NMR (CDCl3): H-2: 3.22 s; H-3: 2.64q (7.1 Hz); H-4: 1.06 t
(7.1 Hz); H-a: 2.86 t (7.2 Hz); H-c,-d,-e: 7.03–7.25 m.13C NMR (CDCl3): C-1: 170.11;
C-2: 58.07; C-3: 48.79; C-4: 11.29; C-a: 19.58; C-b: 134.33; C-c: 129.44; C-d:
The authors are very thankful to Pakistan Science Foundation for
financial support under research project No. PFS/R&D/P-IUB182. The
Spectroscopic NMR lab of Gunma University, Kiryu, Japan is gratefully
acknowledged for measuring the NMR spectra of some compounds
during the postdoctoral fellowship. HEC is also hereby thankful for the
award of nine months abroad (Japan) postdoctoral fellowship. Also
gratefully acknowledged are HEJ Research Institute, University of
Karachi, for spectroscopic analysis and BVH Bahawalpur for supplying
bacterial strains.
References
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129.92; C-e: 124.61.119Sn NMR (CH3)4Sn: −255.25.Compound
5 TBTNNDEG,
[c] D. Kovala-Demertzi, V.N. Dokorou, J.P. Jasinski, A. Opolski, J. Wiecek, M.
Zervou, M.A. Demertzis, J. Organomet. Chem. 690 (2005) 1800.
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[(C4H9)3SnOOCCH2N(C2H5)2] was solidified in n-hexane, mp: 121–124 °C, yield:
74%, soluble in chloroform, methanol and ethanol on heating.CHN analysis (%)
antipyrene: C: 51.42(51.45), N: 3.31 (3.33), H: 9.33 (9.35. IR analysis (cm−1): CO
(carbonyl): 1644asym, 1520sym sb, C_N: 1527 (b) CO (ether linkage):1061 (s) Δν: 120,
Sn–O:733 sp, Sn–C:573 w.sp.1H NMR (CDCl3): H-2: 3.31 s; H-3: 2.54 q(7.2 Hz); H-4:
1.05 t (7.2); H-a: 0.74 t(7.2 Hz); H-b, -c: 1.36- 1.25 m; H-d: 0.94 t(7.2).13C NMR
[8] M. Ashfaq, M.I. Khan, M.K. Baloch, A. Malik, J. Organomet. Chem. 689 (2004) 238.

12
M. Ashfaq et al. / Inorganic Chemistry Communications 14 (2011) 5–12
(CDCl3): C-1: 171.31; C-2: 56.98; C-3: 48.83; C-4: 11.13; C-a: 27.62; C-b: 26.65; C-c:
27.04; C-d: 14.98.119Sn NMR (CH3)4Sn: −133.11.Compound
TPhTNNDEG,
solvent: chloroform, mp: 123–125 °C, yield: 83%, solubility: soluble in chloroform,
6
ethanol and methanol, insoluble in other organic solvents and water.CHN
analysis (%)antipyrene: C: 62.69(62.71), N: 2.59 (2.61), H: 6.57 (6.58).IR analysis
(cm−1): CO(carbonyl): 1630asym, 1504sym sb, C_N: 1529(b) CO (ether linkage):1076
(s) Δν: 126, Sn–O: 734 sp, Sn–C: 574 w.sp.1H NMR (CDCl3): H-2: 3.23 s; H-3: 2.64 t
(7.2 Hz); H-4, -5: 2.34–2.59 m; H-6: 0.93 t (7.2 Hz); H-b, -c,-d: 7.27–7.14 m.13C NMR
(CDCl3): C-1: 175.23; C-2: 59.95; C-3: 55.24; C-4: 29.19; C-5: 21.15; C-6: 15.51; C-a:
134.96 [1 J(119Sn–13C)=649 .6]; C-b: 134.76 2 J (119Sn–13C)=46 .6]; C-c: 27.97 3 J
[(C6H5)3SnOOCCH2N(C2H5)2] was re-crystallized in chloroform, mp: 133–135 °C,
yield: 88%, soluble in chloroform, methanol and ethanol, insoluble in other
organic solvents and water.CHN analysis (%)antipyrene: C: 60.01(60.03), N: 2.90
(2.92), H: 5.66 (5.67). AAS analysis(%): Sn: 24.70 (24.72).IR analysis (cm−1): CO
(carbonyl): 1631asym, 1507sym sb, C_N: 1537(b) CO (ether linkage):1069 (s) Δν: 124,
Sn–O: 738 sp, Sn–C: 571 w.sp.1H NMR (CDCl3): H-2: 3.33 s; H-3: 2.65 q (7.2 Hz); H-
4: 1.05 t(7.2 Hz); H-b, -c, -d: 7.61–7.23 m.13C NMR (CDCl3): C-1: 172.39; C-2: 57.87;
C-3: 48.22; C-4: 11.19; C-a: 134.15 [1 J (119Sn–13C)=648 .9]; C-b: 132.51 [2 J (119Sn–
13C)=48 .7]; C-c: 131.16 [3 J (119Sn–13C)=64.8]; C-d: 129.16.119Sn NMR (CH3)4Sn:
−124.22.Compound 7 TCyTNNDEG, [(C6H11)3SnOOCCH2N(C2H5)2] was re-crystal-
lized in chloroform, mp: 141–142 °C, yield: 77%, soluble in chloroform, methanol and
ethanol, insoluble in other organic solvents and water. When six fold of water was
added its alcoholic solution remained clear.CHN analysis (%) antipyrene: C: 57.83
(57.84), N: 2.79 (2.81), H: 9.09 (9.10).IR analysis (cm−1): CO(carbonyl): 1653asym,
1529sym sb, C_N: 1534(b) CO (ether linkage):1078 (s) Δν: 124, Sn–O: 748 sp, Sn–C:
564 w.sp.1H NMR (CDCl3): H-2: 3.34 s; H-3: 2.89 q (7.2 Hz); H-4: 1.05 t (7.2 Hz); H-
a: 1.10 t (7.2 Hz); H-b: 1.36 q (7.2); H-c, -d: 1.31-1.23 m.13C NMR (CDCl3): C-1:
167.63; C-2: 58.01; C-3: 48.41; C-4: 11.11; C-a: 23.77; C-b: 27.641; C-c: 28.71; C-d:
25.04.119Sn NMR (CH3)4Sn: 74. 24.Compound 8 DBTNNDBG (monomer), [(C4H9)2-
NCH2COO]2SnBu2 was re-crystallizede in chloroform and ethanol 1:2 ratio, mp: 40 °
C, yield: 89%, solubility: soluble in chloroform, methanol and ethanol.CHN analysis
(%) antipyrene: C: 56.83 (56.85), N: 4.41 (4.42), H: 9.79 (9.86).IR analysis (cm−1):
CO(carbonyl): 1630 asym 1510 sym sb, C_N: 1530 (b) CO (ether linkage):1070 (s) Δν:
120. Sn–C: 545 w.sp; Sn–O: 720 sp.1H NMR (CDCl3): H-2: 4.05 s; H-3: 2.61 t (7.2); H-
4: 1.62-1.67 m; H-5: 1.32-1.27 m; H-6: .096 t (7.2 Hz);H-a: 1.25 t (7.1 Hz); H-b, -c:
1.36-1.40 m; H-d: 0.89 t (7.2 Hz).13C NMR(CDCl3): C-1:175.37; C-2: 59.08; C-3:
56.35; C-4: 29.21; C-5: 21.71; C-6: 15.51; C-a: 28.72; C-b: 28.87; C-c: 27.42; C-d:
13.05.119mSn Mössbauer data (mm s−1): QS: 3.38; IS: 1.31; G1: 0.86; G2: 0.84;
δ=QS/IS: 2.58.119Sn NMR (CH3)4Sn: −191. 22.Compound 9 DBTNNDBG (dimer),
[{(C4H9)2NCH2COOSnBu2}2O]2 was re-crystallized in chloroform and ethanol 1:2,
mp: 50 °C, yield: 81%, soluble in chloroform, methanol and ethanol on heating.CHN
analysis (%) antipyrene: C: 52.55 (52.72), N: 2.79 (2.81), H: 6.23 (6.24). IR analysis
(cm−1): CO(carbonyl): 1639asym 1517sym sb, C_N: 1532 (b) CO (ether linkage):1077
(s) Δν: 122. Sn–C: 576 w.sp; Sn–O: 715 sp.1H NMR (CDCl3): H-2: 4.25 s; H-3: 2.51 t
(7); H-4: 1.53-1.59 m; H-5: 1.29-1.25 m; H-6: 0.94 t (7.2 Hz); H-a: 1.02t (7.2 Hz); H-
b: 1.52 t (7.1 Hz); H-c: 1.25 q (7.2 Hz); H-d: 0.91t (7.2 Hz).13C NMR(CDCl3): C-1:
175.37; C-2: 59.08; C-3: 56.35; C-4: 29.21; C-5: 21.71; C-6: 27.3; C-a: 28.64; C-b:
27.67; C-c: 25.12; C-d: 14.91.119mSn Mössbauer data (mm s−1): QS: 3.58; IS: 1.53;
G1: 0.87; G2: 0.82; δ = QS/IS: 2.34.119SnNMR(CH3)4Sn: -199.72, -225.15.Compound
10: TBzTNNDBG, [(C6H4CH2)3SnOOCCH2N(C4H9)2].Re-crystallizing solvent: chloro-
form, mp: 117–118 °C, yield: 80%, solubility: soluble in chloroform, ethanol and
methanol, insoluble in other organic solvents and water.When seven fold of water
was added its alcoholic solution remained clear.CHN analysis (%)antipyrene: C:
66.67 (66.68), N: 2.41 (2.43), H: 7.51 (7.52).IR analysis (cm−1): CO(carbonyl):
1645asym 1521sym sb, C_N: 1529 (b) CO (ether linkage):1067 (s) Δν: 124, Sn–O: 725
sp, Sn–C: 556 w.sp.1H NMR (CDCl3): H-2: 4.50 s; H-3: 2.91 t (7.2 Hz); H-4: 2.42-
2.44 m; H-5: 2.34-2.35 m; H-6: 0.95 t (7.2 Hz); H-a: 2.80 s; H-c, -d, -e: 7.23–
7.04 m.13C NMR (CDCl3): C-1: 174.91; C-2: 61.64; C-3: 54.48; C-4: 28.19; C-5: 23.71;
C-6: 15.51; C-a: 22.45; C-b: 135.63; C-c: 125.67; C-d: 127.84; C-e: 123.98.119Sn NMR
(CH3)4Sn: −155.15.Compound 11 DBzTNNDBG, [(C6H4CH2)2Sn{OOCCH2N
(C4H9)2}2] was solidified in chloroform, mp: 210–212 °C, yield: 78%, soluble in
chloroform, methanol and ethanol, DMSO insoluble in other organic solvents and
water. When eight foldof waterwasadded its alcoholic solution remainedclear. CHN
analysis (%)antipyrene: C: 64.12 (64.13), N: 4.26 (2.27), H: 8.59 (8.61).IR analysis
(cm−1): CO(carbonyl): 1636asym, 1517sym sb, C_N: 1530 (b) CO (ether linkage):1061
(s) Δν: 119, Sn–O: 730 sp, Sn–C: 570 w.sp.1H NMR (CDCl3): H-2: 3.46 s; H-3: 2.71 t
(7.2 Hz); H-4, -5: 2.32–2.25 m; H-6: 0.96 t (7.2 Hz); H-a: 2.71 s; H-c, -d, -e: 7.2–
7.34 m.13C NMR (CDCl3): C-1: 175.31; C-2: 62.44; C-3: 55.88; C-4: 29.29; C-5: 23.55;
C-6: 16.51; C-a: 21.44; C-b: 136.33; C-c: 126.16; C-d: 128.44; C-e: 124.88.119Sn NMR
(CH3)4Sn: −266.12.Compound 12 TBTNNDBG, [(C4H9)3SnOOCCH2N(C4H9)2] was
solidified in n-hexane, mp: 145–147 °C, yield: 89%, soluble in chloroform, soluble in
ethanol on heating, slightly soluble in methanol and insoluble in water.CHN analysis
(%)antipyrene: C:55.45(55.47), N: 2.93 (2.94), H: 9.94 (9.95).IR analysis (cm−1): CO
(carbonyl): 1644asym, 1519sym sb, C_N: 1528 (b) CO (ether linkage):1065 (s) Δν: 125,
Sn–O: 732 sp, Sn–C: 577 w.sp.1H NMR (CDCl3): H-2: 4.61 s; H-3: 2.98 t (7.2 Hz); H-4,
-5: 2.37–2.45 m; H-6: 0.95 t (7.2 Hz); H-a: 0.81 t (7.2 Hz); H-b, -c: 1.12–0.98 m; H-d:
0.96 t (7.2 Hz).13C NMR (CDCl3): C-1: 181.31; C-2: 62.44; C-3: 55.88; C-4: 29.29; C-5:
21.54; C-6: 16.51; C-a: 28.56; C-b: 26.98; C-c: 27.97; C-d:14.88.119SnNMR (CH3)4Sn:
-139.71.Compound 13: TPhTNNDBG, [(C6H5)3SnOOCCH2N(C4H9)2].Re-crystallizing
(
119Sn–13C)=66.6); C-d: 131.74.119Sn NMR (CH3)4Sn: −127.87.Compound 14
TCyTNNDBG, [(C6H11)3SnOOCCH2N(C4H9)2].Re-crystallizing solvent: chloroform,
mp: 120–121 °C, yield: 87%, solubility: soluble in chloroform, ethanol and methanol,
insoluble in other organic solvents and water.When six fold of water was added its
alcoholic solution remained clear.CHN analysis (%)antipyrene: C: 60.64(60.66), N:
2.51 (2.53), H: 9.63 (9.64).IR analysis (cm−1): CO(carbonyl): 1632asym, 1508sym sb,
C_N: 1534(b) CO (ether linkage):1078 (s) Δν: 124, Sn–O: 738 sp, Sn–C: 578 w.sp.1H
NMR (CDCl3): H-2: 3.54 s; H-3: 2.69 t (7.2 Hz); H-4, -5: 1.55 -1.59 m; H-6: 0.95 t
(7.2 Hz); H-a: 1.25 t (7.2 Hz); H-b: 1.61; H-c: 1.41; H-d: 1.45.13C NMR (CDCl3): C-1:
170.43; C-2: 59.23; C-3: 55.14; C-4: 29.19; C-5: 20.17; C-6: 14.11; C-a: 23.44; C-b:
27.4; C-c: 29.96; C-d: 20.06.119Sn NMR (CH3)4Sn: 82.34.
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