Self-assembled pentagonal bipyramidal and skew trapezoidal organotin(IV) complexes of substituted benzoic acids: Their antibacterial, antifungal, cytotoxic, insecticidal and urease inhibition activities

Article abstract of DOI:10.1016/j.ica.2011.01.007

Fourteen di- and triorganotin(IV) derivatives with pentagonal bipyramidal and skew trapezoidal geometries have been synthesized and characterized. Dimethylstannyl bis[3-amino-4-chlorophenylcarboxylate] (1), bis[3-amino-4- chlorophenylcarboxylato] tetraeth

Full text of DOI:10.1016/j.ica.2011.01.007

Inorganica Chimica Acta 370 (2011) 27–35
Contents lists available at ScienceDirect
Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Self-assembled pentagonal bipyramidal and skew trapezoidal organotin(IV)
complexes of substituted benzoic acids: Their antibacterial, antifungal,
cytotoxic, insecticidal and urease inhibition activities
a
a
Aziz-ur-Rehman a,b, Mukhtiar Hussain b, Zia-ur-Rehman b, Saqib Ali b, , Abdul Rauf , Faiz ul Hassan Nasim ,
⇑
Madeleine Helliwell c
a Department of Chemistry, The Islamia University of Bahawalpur, Pakistan
b Department of Chemistry, Quaid-i-Azam University, Islamabad-45320, Pakistan
c School of Chemistry, University of Manchester, Manchester M13 9PL, UK
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 27 June 2010
Received in revised form 1 December 2010
Accepted 8 January 2011
Available online 13 January 2011
Fourteen di- and triorganotin(IV) derivatives with pentagonal bipyramidal and skew trapezoidal
geometries have been synthesized and characterized. Dimethylstannyl bis[3-amino-4-chlorophenylcarb-
oxylate] (1), bis[3-amino-4-chlorophenylcarboxylato] tetraethyldistannoxane] (2) and bis[3,5-dinitro-
4-chlorophenylcarboxylato] tetra-n-butyldistannoxane (10) are dinuclear and tetranuclear complexes
of bidentate ligands. The crystal structure of (1) is dimeric in which each Sn atom is seven coordinated.
Study of weak intramolecular Snꢀ ꢀ ꢀO interactions is very important to decide geometry around tin.
Furthermore, it has been investigated that these compounds exhibit fairly good antibacterial, antifungal,
cytotoxic, insecticidal and antiurease activities.
Keywords:
Organotin(IV) derivatives
Secondary interactions
Multinuclear NMR
X-ray crystallography
Biological studies
Ó 2011 Elsevier B.V. All rights reserved.
1. Introduction
promising antifungal, antibacterial and antitumor activities
[7–12]. Their activity depends upon the nature of carboxylate igands
Organotin(IV) carboxylates have been extensively studied due
to their structural chemistry and biological applications. The diver-
sity in structure of these compounds is due to the ability of carbox-
ylate ligand to bind with Sn centre in monodentate, bidentate and
bridging manner. These anionic ligands are highly effective for
metals due to the reason that steric and electronic factors of organ-
ic substituents on tin make the complexes more stable. Dimeric
tetraorganodicarboxylato stannoxanes are important class of
organotin compounds having variety in coordination around tin
both in solid and solution states as well. The Lewis acid properties
of such type of compounds are helpful for catalysis of various car-
bonyl transformations under virtually inert conditions [1].
and alkyl/aryl groups bonded to Sn atom. Normally, triorganotin(IV)
compounds display a higher biological activity than their di- and
mono-organotin(IV) analogues due to their ability to bind with pro-
teins [13–16].
Our research group has made efforts to know the competitive
coordination modes of different S, N and O donor ligands around
tin atom and to find a rationale, related to the stability and struc-
tural motifs of this class of compounds [17–20]. As an extension of
this work, we report herein the synthesis, spectroscopic analysis,
X-crystallography and biological properties of fourteen organo-
tin(IV) derivatives of substituted benzoic acids.
Furthermore, the biological and industrial applications of
organotin(IV) complexes are well documented also. The presence
of longer molecular interactions in these complexes affects their
biological properties. The broad spectrum of applications wrap their
usage as antifouling paints [2–4], homogeneous catalysts in
esterification, trans esterification reactions [5], and ion carriers in
electrochemical membranes design [6]. These complexes exhibit
2. Experimental
2.1. Materials and methods
Reagents, di-, triorganotin(IV) chlorides and ligands were pur-
chased from commercial sources (Aldrich, USA) and were used
without further purification. Solvents were dried before use by
the literature procedure [21]. Elemental analyses (C, H and N) were
carried out by Leco CHNS-932 analyzer USA while multi EAÒ 5000
series analyzer Germany was used for chlorine analysis. Infrared
⇑
Corresponding author. Tel.: +92 51 90642130; fax: +92 51 90642241.
E-mail address: drsa54@yahoo.com (S. Ali).
0020-1693/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2011.01.007

28
Aziz-ur-Rehman et al. / Inorganica Chimica Acta 370 (2011) 27–35
O2N
COOsym), 497 m(Sn–C), 423 m(Sn–O), 3371 m
(NH). 1H NMR d (ppm)
6
7
3
O
7
3
nJ[119Sn, 1H] Hz: 1.06[76] (s, 6H, H ), 6.89 (s, 2H, H3), 7.72 (d, 2H,
6
O
a
H6) 3J[7.1], 7.86 (d, 2H, H7) 3J[7.1], 5.71 (s, 4H, NH). 13C NMR d
Cl
C
OH
Cl
C
OH
5
2
1
5
2
1
(ppm) nJ[119Sn, 13C]Hz: ꢁ1.7[645] C , 173.3 C1, 128.7 C2, 119.6
a
4
4
C3, 138.4 C4, 126.3 C5, 129.4 C6, 121.2 C7. 119Sn NMR d (ppm):
ꢁ136.9.
H N
2
O2N
Scheme 1. Numbering scheme of ligands atoms in complexes (1–14).
2.2.2. Bis[3-amino-4-chlorophenylcarboxylato]
tetraethyldistannoxane] (2)
(IR) measurements were taken as KBr pellets on a Bio-Rad Excali-
bur FT-IR, model FTS 4800 MX spectrophotometer (USA) in the fre-
C44H60Cl4N4O10Sn4, M.P. 190–192 °C, Yield 76%, Anal. Calc.: C,
quency range of 4000–200 cmꢁ1 1H, 13C and 119Sn NMR spectra in
.
37.2; H, 4.2; N, 3.9; Cl, 10.0. Found: C, 38.1; H, 3.8; N, 4.5; Cl,
9.9%. Recrystallization: chloroform and n-hexane in 4:1. IR (KBr):
solution were undertaken using Bruker ARX 300, 400 and
500 MHz-FT-NMR spectrometers, respectively. The chemical shifts
are reported in ppm relative to the external references, tetrameth-
ylsilane (TMS) for 1H, 13C and tetramethyltin for 119Sn shifts. Crys-
tallographic studies were carried out on a Nonius Kappa CCD
1693
1563
559, 502
m
m
(COO)asym, 1438
(COO)asym, 1430
m
(COO)sym
,
D
m
(
m
D
COOasym
ꢁ
m
COOsym) 255,
COOsym),
m
(COO)sym, 133
m
(m
COOasym
ꢁ
m
m
(Sn–C), 483, 440
m
(Sn–O)2, 286, 252 (Sn–O). 1H NMR d
(ppm) nJ[119Sn, 1H] Hz: 1.40–1.27 (m, 20H, H , Hb), 7.20 (s, 2H,
a
diffractometer with graphite monochromated Mo Ka radiation.
H3), 7.55 (d, 2H, H6) 3J[7.2], 7.62 (d, 2H, H7) 3J[7.2], 4.19 (s, 4H,
NH). 13C NMR d (ppm) nJ[119Sn, 13C]Hz: 17.8[604], 16.4[584] C ,
a
2.2. General procedure for synthesis of complexes
9.7[58], 8.4[49] Cb, 172.3 C1, 129.0 C2, 117.0 C3, 143.0 C4, 132.2
C5, 129.4 C6, 120.8 C7. 119Sn NMR d (ppm): ꢁ211.8, ꢁ163.3.
All compounds (1–14) were prepared by reaction of organo-
tin(IV) oxides/hydroxides/chlorides with carboxylic acids/Na-salts
as already discussed [17,18]. Synthesis of all compounds is given
in Scheme 1. Dimeric stannoxanes were also prepared by partial
hydrolysis of diorganotin(IV) derivatives. The spectral data of all
compounds is arranged as numbered in Scheme 2.
2.2.3. Di-n-butylstannyl bis[3-amino-4-chlorophenylcarboxylate] (3)
C22H28N2O4Cl2Sn, M.P. 105–107 °C, Yield 84%, Anal. Calc.: C,
46.0; H, 4.9; N, 4.9; Cl, 12.3. Found: C, 45.4; H, 4.5; N, 4.2; Cl,
12.2%. Recrystallization: chloroform and n-hexane in 4:1. IR
(KBr): 1636
m
(COO)asym, 1489
m
(COO)sym, 147
D
m
(
m
COOasym
ꢁ
m-
2.2.1. Dimethylstannyl bis[3-amino-4-chlorophenylcarboxylate] (1)
COOsym), 582 m(Sn–C), 474 m(Sn–O), 3351 m
(NH). 1H NMR d (ppm)
C16H16N2O4Cl2Sn, M.P. 130–132 °C, Yield 83%, Anal. Calc.: C,
nJ[119Sn, 1H] Hz: 1.36[77] (t, 4H, H ), 3J[7.5], 1.36–1.41 (m, 8H,
a
39.2; H, 3.3; N, 5.7; Cl, 14.5. Found: C, 38.4; H, 3.9; N, 4.9; Cl,
14.4%. Recrystallization: chloroform and n-hexane in 4:1. IR
Hb, H ), 0.91 (t, 6H, Hd) 3J[7.5], 7.23 (s, 2H, H3), 7.58 (d, 2H, H6)
c
3J[7.1], 7.62 (d, 2H, H7) 3J[7.2], 4.2 (s, 4H, NH). 13C NMR d (ppm)
nJ[119Sn, 13C]Hz: 25.5[569] C , 29.4[34] Cb, 26.6[93] C , 13.5 Cd,
(KBr): 1638
m(COO)asym, 1498
m(COO)sym, 140
D
m
(mCOOasym
ꢁ
m-
a
c
Scheme 2. Schematic diagram for synthesis of compounds (1–14).

Aziz-ur-Rehman et al. / Inorganica Chimica Acta 370 (2011) 27–35
29
175.5 C1, 129.3 C2, 117.4 C3, 142.8 C4, 124.1 C5, 129.4 C6, 120.8 C7.
2.2.9. Diethylstannyl bis[3,5-dinitro-4-chlorophenylcarboxylate] (9)
119Sn NMR d (ppm): ꢁ150.3.
C18H14N4O12Cl2Sn, M.P. 222–225 °C, Yield 89%, Anal. Calc.: C,
32.4; H, 2.1; N, 8.4; Cl, 10.6. Found: C, 31.8; H, 1.9; N, 8.1; Cl,
10.5%. Recrystallization: chloroform and n-hexane in 4:1. IR
2.2.4. Di-n-octylstannyl bis[3-amino-4-chlorophenylcarboxylate] (4)
(KBr): 1645
COOsym), 552
m
m
(COO)asym, 1496
m
(COO)sym, 149
D
m
(
m
COOasym
ꢁ
m-
C30H44N2O4Cl2Sn, M.P. 286–288 °C, Yield 83%, Anal. Calc.: C,
(Sn–C), 484 m
(Sn–O). 1H NMR d (ppm) nJ[119Sn, 1H]
52.5; H, 6.5; N, 4.0; Cl, 10.3. Found: C, 51.7; H, 6.1; N, 3.7; Cl,
10.2%. Recrystallization: chloroform and n-hexane in 4:1. IR
Hz: 1.48[79] (q, 4H, H ), 3J[7.3], 1.18 (t, 6H, Hb), 3J[7.3], 8.52 (s,
a
4H, H3,7). 13C NMR d (ppm) nJ[119Sn, 13C]Hz: 18.4[551] C , 8.4[45]
a
(KBr): 1674
COOsym), 541
nJ[119Sn, 1H] Hz: {1.08–1.70 m, 0.53–0.70 m, 0.76 t(7.2 Hz), 34H,
m
m
(COO)asym, 1489
m
(COO)sym, 185
D
m
(m
COOasym
ꢁ
m-
Cb, 169.5 C1, 130.1 C2, 134.7 C3,7, 148.9 C4,6, 127.4 C5. 119Sn NMR
(Sn–C), 483 (Sn–O), 3316
m
m
(NH). 1H NMR d (ppm)
d (ppm): ꢁ156.5.
0
0
0
0
H , Hb, H , Hd, H , Hb , H , Hd }, 7.24 (s, 2H, H3), 7.51 (d, 2H, H6)
a
c
a
c
2.2.10. Bis[3,5-dinitro-4-chlorophenylcarboxylato] tetra -n-
butyldistannoxane (10)
3J[6.9], 7.59 (d, 2H, H7) 3J[7.1], 5.14 (s, 4H, NH). 13C NMR d (ppm)
nJ[119Sn, 13C]Hz: 25.2[554] C , 24.6[34] Cb, 32.4[94] C , {13.8,
a
c
C60H80N8O26Cl4Sn4, M.P. 240–243 °C, Yield 93%, Anal. Calc.: C,
0
0
0
0
23.9, 29.1, 29.3, 32.6, Cd, C , Cb , C , Cd }, 171.8 C1, 130.1 C2,
a
c
37.0; H, 4.1; N, 5.8; Cl, 7.3. Found: C, 37.6; H, 3.0; N, 7.2; Cl, 7.2%.
Recrystallization: chloroform and n-hexane in 4:1. IR (KBr): 1674,
119.4 C3, 142.6 C4, 133.2 C5, 128.1 C6, 121.4 C7. 119Sn NMR (d
(ppm): ꢁ163.7.
1576 COOasym
m
(COO)asym, 1439, 1430
m(COO)sym, 235, 146
D
m(m
ꢁ
m
COOsym), 531, 513 m(Sn–C), 484, 431 m(Sn–O)2, 274, 233 (Sn–O).
1H NMR d (ppm) nJ[119Sn, 1H] Hz: 0.91 (t, 24H, Hd(endo), Hd(exo)
3J[7.2] Hz, 1.32–1.44 (m, 48H, H (endo), Hb(endo), H (endo), H
)
,
2.2.5. Trimethylstannyl [3-amino-4-chlorophenylcarboxylate] (5)
10H14NO2ClSn, M.P. 130–133 °C, Yield 83%, Anal. Calc.: C, 35.9;
H, 4.2; N, 4.2; Cl, 10.6. Found: C, 35.2; H, 3.9; N, 3.6; Cl, 10.5%.
a
c
a
(exo)
C
H
b(exo), H (exo)), 8.52 (s, 8H, H3,7). 13C NMR d (ppm) nJ[119Sn, 13C]
c
Hz: 25.4[648], 25.9[584] C , 27.6[36], 27.1[30] Cb, 26.8[94],
a
Recrystallization: chloroform and n-hexane in 4:1. IR (KBr):
26.4[79] C , 13.2, 13.7 Cd, 171.5 C1, 130.1 C2, 134.4 C3,7, 148.6 C4,6
,
c
1630s
m
(COO)asym
,
1489 m
(Sn–C), 437w
m
(COO)sym
,
141
D
m
(m
COOasym
ꢁ
127.1 C5. 119Sn NMR d (ppm): ꢁ196.5, ꢁ200.1.
m
COOsym), 581 m
m
m
(Sn–O), 3368 m
(NH). 1H NMR d
(ppm) nJ[117/119Sn, 1H] Hz: 0.88[55, 58] (s, 9H, H ), 7.1 (s, 1H, H3),
a
7.3 (d, 1H, H6) 3J[7.3], 7.48 (d, 1H, H7) 3J[7.3], 4.01 (s, 1H, NH).
2.2.11. Di-n-octylstannyl bis[3,5-dinitro-4-chlorophenylcarboxylate]
(11)
13C NMR d (ppm) nJ[117/119Sn, 13C]Hz: ꢁ2.2[376, 394] C , 171.2
a
C30H38N4O12Cl2Sn, M.P. 151–154 °C, Yield 90%, Anal. Calc.: C,
C1, 129.0 C2, 117.3 C3, 142.6 C4, 131.2 C5, 129.1 C6, 120.6 C7.
119Sn NMR d (ppm): 141.7.
43.1; H, 4.6; N, 6.7; Cl, 8.5. Found: C, 42.3; H, 3.9; N, 6.5; Cl,
8.4%. Recrystallization: chloroform and n-hexane in 4:1. IR (KBr):
1637
557
m
(COO)asym, 1479
m
(COO)sym, 158
D
m
(
m
COOasym
ꢁ
mCOOsym),
(Sn–O). 1H NMR d (ppm) nJ[119Sn, 1H] Hz:
2.2.6. Tri-n-butylstannyl [3-amino-4-chlorophenylcarboxylate] (6)
m(Sn–C), 460
m
C19H32NO2ClSn, M.P. 285–287 °C, Yield 83%, Anal. Calc.: C, 49.5;
{1.56–1.73 m, 1.53–1.73 m, 0.94 t(7.2 Hz), 34H, H , Hb, H , Hd,
a
c
H , Hb , H , Hd }, 8.30 (s, 4H, H3,7). 13C NMR d (ppm) nJ[119Sn,
H, 7.0; N, 3.0; Cl, 7.7. Found: C, 48.6; H, 6.7; N, 2.7; Cl, 7.6%. Recrys-
tallization: chloroform and n-hexane in 4:1. IR (KBr): 1643
0
0
0
0
a
c
13C]Hz: 25.2[476] C , 24.6[36] Cb, 32.4[97] C , {33.5, 33.0, 32.6,
a
c
m
m
(COO)asym, 1458
m
(COO)sym, 174
D
m
(
m
COOasym
ꢁ
mCOOsym), 580
0
0
0
0
29.3, 29.2, 29.1, 22.7, 14.0, Cd, C , Cb , C , Cd }, 170.3 C1, 128.3 C2,
a
c
(Sn–C), 469w (Sn–O), 3309
m
m
a
(NH). 1H NMR d (ppm) nJ[119Sn,
130.6 C3,7, 149.3 C4,6, 128.1 C5. 119Sn NMR (d (ppm): ꢁ163.7.
1H] Hz: 1.33–1.69 (m, 18H, H , Hb, H ), Hd 0.86 (t, 9H, 3J[7.3],
c
7.28 (s, 1H, H3), 7.43 (d, 1H, H6) 3J[7.2], 7.58 (d, 1H, H7) 3J[7.2]
7.2 Hz, 4.21 (s, 2H, NH). 13C NMR d (ppm) nJ[117 119Sn,13C]Hz:
2.2.12. Trimethylstannyl [3,5-dinitro-4-chlorophenylcarboxylate] (12)
/
C10H11N2O6ClSn, M.P. 212–215 °C, Yield 91%, Anal.Calc.: C, 29.3;
16.4[344, 351] C , 27.1[34] Cb, 29.4[92] C , 13.7 Cd, 171.8 C1,
a
c
H, 2.7; N, 6.8; Cl, 8.7. Found: C, 28.4; H, 2.4; N, 7.1; Cl, 8.6%. Recrys-
tallization: chloroform and n-hexane in 4:1. IR (KBr): 1634
128.9 C2, 118.5 C3, 140.0 C4, 125.6 C5, 130.2 C6, 119.8 C7. 119Sn
NMR d (ppm): 117.3.
m(COO)asym, 1465
m
(COO)sym, 169
D
m
(m
COOasym
ꢁ
mCOOsym), 544
m
(Sn–C), 433
m
(Sn–O). 1H NMR d (ppm) nJ[117/119Sn, 1H] Hz:
0.88[55, 57] (s, 9H, H ), 8.72 (s, 2H, H3,7). 13C NMR d (ppm) nJ[117/
a
2.2.7. Triphenylstannyl [3-amino-4-chlorophenylcarboxylate] (7)
119Sn, 13C]Hz: 1.03[374, 396] C , 166.5 C1, 129.1 C2, 124.3 C3,7
,
a
C25H20NO2ClSn, M.P. 152–155 °C, Yield 81%, Anal. Calc.: C, 57.7;
149.4 C4,6), 128.7 C5. 119Sn NMR d (ppm): 141.7.
H, 3.9; N, 2.7; Cl, 6.8. Found: C, 57.3; H, 3.4; N, 2.3; Cl, 6.7%. Recrys-
tallization: chloroform and n-hexane in 4:1. IR (KBr): 1615
2.2.13. Tri-n-butylstannyl [3,5-dinitro-4-chlorophenylcarboxylate]
(13)
C19H29N2O6ClSn, M.P. 230–232 °C, Yield 85%, Anal.Calc.: C, 42.6;
H, 5.5; N, 5.2; Cl, 6.6. Found: C, 41.8; H, 5.1; N, 4.8; Cl, 6.5%. Recrys-
tallization: chloroform and n-hexane in 4:1. IR (KBr): 1640
m
m
(COO)asym, 1430s
m
(COO)sym, 185
D
m(
m
COOasym
ꢁ
mCOOsym), 263
(Sn–C), 440 (Sn–O), 3374
m
m
(NH). 1H NMR d (ppm) nJ[119Sn, 1H]
Hz: 7.49–7.81 (m, 15H, Hb, H , Hd), 7.28–7.46 (m, 3H, H3, H6, H7),
c
4.12 (s, 2H, NH). 13C NMR (d (ppm) nJ[117/119Sn, 13C] Hz:
137.2[645, 663] C , 136.6[46] Cb, 128.3[61] C , 128.9 Cd, 172.2 C1,
a
c
m
(COO)asym, 1464
m
(COO)sym, 176
D
d
m
(m
COOasym
ꢁ
mCOOsym), 509
130.3 C2, 142.7 C3, 142.3 C4, 129.4 C5, 121.1 C6, 129.8 C7. 119Sn
m(Sn–C), 464
m
(Sn–O). 1H NMR
(ppm) nJ[119Sn, 1H] Hz:
NMR d (ppm): 148.4.
{1.61(bs), 1.36–1.41(m), 18H, H , Hb, H ), 0.86 (t, 9H, Hd)
a
c
3J[1H,1H] 7.3 Hz 7.97 (s, 2H, H3,7). 13C NMR d (ppm) nJ[117/119Sn,
2.2.8. Dimethylstannyl bis[3,5-dinitro-4-chlorophenylcarboxylate] (8)
13C]Hz: 16.2[372, 386] C , 27.2[29] Cb, 26.5[97] C , 14.0 Cd, 172.8
a
c
C16H10N4O12Cl2Sn, M.P. 133–135 °C, Yield 95%, Anal. Calc.: C,
C1, 130.3 C2, 123.7 C3,7, 147.6 C4,6), 128.7 C5. 119Sn NMR d (ppm):
30.0; H, 1.6; N, 8.8; Cl, 11.1. Found: C, 29.1; H, 1.0; N, 8.3; Cl,
143.9.
11.0%. Recrystallization: chloroform and n-hexane in 4:1. IR
(KBr): 1654
COOsym), 291
m
m
(COO)asym, 1478
m
(COO)sym, 176
D
m
(
m
COOasym
ꢁ
m-
2.2.14. Triphenylstannyl [3,5-dinitro-4-chlorophenylcarboxylate] (14)
C25H17N2O6ClSn, M.P. 141–144 °C, Yield 65%, Anal.Calc.: C, 50.4;
H, 2.9; N, 4.7; Cl, 6.0. Found: C, 49.6; H, 2.5; N, 4.3; Cl, 5.9%. Recrys-
tallization: chloroform and n-hexane in 4:1. IR (KBr): 1648
(Sn–C), 430 m
(Sn–O). 1H NMR d (ppm) nJ[119Sn, 1H]
Hz: 1.12[76] (s, 6H, H ), 8.42 (s, 4H, H3,7). 13C NMR d (ppm) nJ[119Sn,
a
13C]Hz: 1.0[652] C , 170.3 C1, 130.5 C2, 125.1 C3,7, 149.7 C4,6, 128.8
a
C5. 119Sn NMR d (ppm): ꢁ128.4.
m(COO)asym, 1467
m(COO)sym, 181
D
m
(mCOOasym
ꢁ
mCOOsym), 291

30
Aziz-ur-Rehman et al. / Inorganica Chimica Acta 370 (2011) 27–35
Fig. 1. Asymmetric unit of compound with numbering without interactions (1).
m
(Sn–C), 443 m
(Sn–O). 1H NMR d (ppm) nJ[119Sn, 1H] Hz: {7.28–7.63,
7.71–7.9 m, 15H, Hb, H , Hd), 8.66 (s, 2H, H3,7). 13C NMR d (ppm)
c
nJ[117/119Sn, 13C]Hz: 138.4[649, 664] C 136.9[42] Cb, 128.9[70]
a
C , 129.3 Cd, 167.1 C1, 130.5 C2, 123.5 C3,7, 149.4 C4,6), 128.3 C5.
c
119Sn NMR d (ppm): ꢁ109.3.
Fig. 2. Dimeric structure of compound (1) showing intermolecular interactions.
3. Results and discussion
3.2. NMR spectroscopy
3.1. Vibrational spectroscopy
1H NMR data is given in experimental section and resonances
for compounds (1–14) have been assigned. In compounds (1–7),
downfield shift (5.71–4.01 ppm) of amino group indicates that this
site remains protonated showing no coordination while disappear-
ance of acidic protons in all compounds recognize that coordina-
tion occurs through this site. The aromatic protons were also
assigned with well resolved coupling due to neighbouring protons.
The most interesting feature is nJ[119Sn, 1H] coupling values which
are used to asses the coordination number around Sn. 2J values cal-
culated for dimethyltin (1, 8) 2J [76 Hz], diethyltin (9) 2J [79 Hz], di-
n-butyltin (3) 2J [77 Hz] and trimethyltin ( 5, 12) 2J [55/58, 55/
57 Hz] appear in the range normally five coordinated for diorgano-
tin and four for triorganotin(IV) compounds [18,26]. In compounds
(2) and (10), exo- and endocyclic protons of ethyl and butyl groups
appear at different d values but signals are intermixed due to over-
lapping. However, the presence of these resonances is in agree-
ment with pair wise heterotopic non-equivalence of the exocyclic
and endocyclic Et2Sn and Bu2Sn moieties. Similarly, a complex pat-
tern is observed for butyl protons of compounds 3, 6 and 13 due to
The vibrational frequencies of OCO, Sn–C, Sn–O and Sn–O–Sn
moieties are taken into consideration. These frequencies provide
useful information to identify the coordination around tin
[22,23]. The characteristic absorption signals of carboxylate group
for compounds 1, 3–9 and 11–14 are assigned in the range 1615–
1674 cmꢁ1 for asymmetric stretching and 1430–1498 cmꢁ1 for
symmetric stretching frequencies. A set of two sharp peaks for
asymmetric (1674–1693 and 1576–1563 cmꢁ1) and symmetric
frequencies (1438–1439 and 1430 cmꢁ1) is observed for com-
pounds 2 and 10, respectively.
Dt
values (133–185 cmꢁ1) for all
compounds point towards bridging bidentate mode of ligand
around Sn atom. In case of dimeric distannoxanes 2 and 10, the
carboxylate ligand exhibits anisobidentate mode of coordination.
These values suggest that skew trapezoidal geometry exists in
diorganotin(IV) complexes while triorganotin(IV) complexes retain
trigonal bipyramidal geometry in solid state. The vibration signals
for Sn–C, Sn–O and O–Sn–O moieties are observed in their ex-
pected region [24,25].
Table 1
Crystal data and structure refinement parameters for complexes (1) and (2).
Empirical formula
C16H16Cl2N2O4Sn (1)
C44H60Cl4N4O10Sn4 (2)
C60H80Cl4N8O26Sn4 (10)
Formula weight
Crystal system
Space group
a (Å)
b (Å)
c (Å)
489.90
1421.52
monoclinic
C2/c
17.810(2)
13.8787(17) Å
22.693(3) Å
90
103.7
1945.88
triclinic
P1
12.178(11)
12.514(12)
13.568 (12)
104.59(10)
110.77(10)
95.96(10)
triclinic
ꢀ
ꢀ
P1
9.0688(9)
10.7486(11)
11.0411(12)
113.9310(10)
110.283(2)
93.623(2)
896.28(16)
2
a
(°)
b (°)
c
(°)
90
V (Å3)
5449.1(12)
4
1.733
1827.9(3)
1
1.768
Z
Dcalc (mg/m3)
Crystal size (mm3)
F(0 0 0)
1.815
0.50 ꢂ 0.40 ꢂ 0.30
0.50 ꢂ 0.40 ꢂ 0.40
0.40 ꢂ 0.20 ꢂ 0.20
484
2800
972
Total reflections
Independent reflections
R indices (all data)
Final R indices [I > 2r(I)]
Goodness-of-fit (GOF)
3593
15 315
5514
R1 = 0.0563, wR2 = 0.1270
R1 = 0.0448, wR2 = 0.1162
1.043
14 580
7352
R1 = 0.0374, wR2 = 0.0864
R1 = 0.0324, wR2 = 0.0835
1.030
R1 = 0.0246, wR2 = 0.602
R1 = 0.0233, wR2 = 0.0595
1.073
Theta range for data collection (°)
2.27–26.37
1.85–26.40
1.69–26.46°

Aziz-ur-Rehman et al. / Inorganica Chimica Acta 370 (2011) 27–35
31
Table 2
Selected bond lengths and bond angles of compounds (1), (2) and (10).
Compound (1)
Compound (2)
Compound (10)
Sn(1)–C(15)
Sn(1)–C(16)
Sn(1)–O(2)
Sn(1)–O(4)
Sn(1)–O(3)
Sn(1)–O(1)
Sn(1)–C(8)
C(l1)–C(5)
2.099(2)
2.103(2)
2.2038(16)
2.2113(16)
2.3461(17)
2.4382(16)
2.648(2)
1.742(2)
1.265(3)
106.5(2)
162.98(10)
97.01(9)
95.33(8)
95.52(8)
97.10(8)
142.88(6)
57.44(6)
88.71(8)
88.50(8)
56.08(6)
141.50(6)
161.02(6)
91.02(8)
94.47(8)
Sn(1)–O(1)
Sn(1)–C(8)
Sn(1)–C(10)
Sn(1)–C(1)#1
Sn(1)–O(6)
Sn(2)–O(1)
Sn(2)–C(21)
Sn(2)–C(19)
2.049(3)
2.213(6)
2.130(5)
2.169(3)
2.224(3)
2.002(3)
2.122
2.145(7)
2.183(3)
2.169(3)
1.258(3)
105.5(2)
76.66(12)
96.87(19)
93.9(2)
91.86(13)
88.0(2)
87.4(2)
91.86(13)
168.38(13)
112.79(19)
109.5(3)
137.5(3)
80.53(11)
Sn(1)–O(13)
Sn(1)–C(19)
Sn(1)–C(15)
Sn(1)–O(1)
Sn(1)–O(7)
Sn(2)–O(13)#1
Sn(2)–C(23)
Sn(2)–O(13)
Sn(2)–Sn(2)#1
Sn(2)–O(8)
O(13)–Sn(1)–C(15)
C(19)–Sn(1)–C(15)
O(13)–Sn(1)–O(1)
C(19)–Sn(1)–O(1)
C(15)–Sn(1)–O(1)
O(13)–Sn(1)–O(7)
C(19)–Sn(1)–O(7)
C(15)–Sn(1)–O(7)
O(1)–Sn(1)–O(7)
C(23)–Sn(2)–O(13)
O(13)–Sn(2)–O(8)
C(1)–O(1)–Sn(1)
C(8)–O(7)–Sn(1)
Sn(1)–O(13)–Sn(2)
2.0394(19)
2.125(3)
2.135(3)
2.187(2)
2.286(2)
2.037(2)
2.119(3)
2.1708(19)
3.2907(5)
2.276(2)
108.70(10)
144.28(12)
83.09(8)
99.15(10)
93.15(10)
89.89(8)
86.79(10)
85.11(11)
171.82(8)
97.17(10)
168.57(8)
108.57(18)
135.0(2)
O(1)–C(1)
Sn(2)–O(7)
O(1)–Sn(1)#1
O(3)–C(8)
O(1)–Sn(1)–C(8)
C(15)–Sn(1)–C(16)
C(15)–Sn(1)–O(2)
C(16)–Sn(1)–O(2)
C(15)–Sn(1)–O(4)
C(16)–Sn(1)–O(4)
O(2)–Sn(1)–O(3)
O(4)–Sn(1)–O(3)
C(15)–Sn(1)–O(1)
C(16)Sn(1)–O(1)
O(2)–Sn(1)–O(1)
O(4)–Sn(1)–O(1)
O(3)–Sn(1)–O(1)
C(15)–Sn(1)–C(8)
C(16)–Sn(1)–C(8)
O(1)–Sn(1)–C(10)
O(1)–Sn(1)–O(1)#1
C(8)–Sn(1)–O(1)#1
C(10)–Sn(1)–O(1)1
O(1)–Sn(1)–O(6)
C(8)–Sn(1)–O(6)
C(10)–Sn(1)–O(6)
O(1)–Sn(1)–O(6)
O(1)#1–Sn(1)–O(6)
O(1)–Sn(2)–C(21)
O(1)–Sn(2)–C(19)
C(21)–Sn(2)–C(19)
O(1)–Sn(2)–O(7)
120.81(9)
CH2–CH2–CH2– skeleton in the normal reported range (1.36–
1.41 ppm), (1.33–1.69 ppm) and terminal methyl protons demon-
strate triplets at 0.86 and 0.91 ppm, respectively. The aromatic
2J[34 Hz], 3J[93 Hz], 4 1J[554 Hz], 2J[34 Hz], 3J[94 Hz], 8 1J[652 Hz],
9
1J[551 Hz], 2J[45 Hz], 10 1J[648 Hz, 584 Hz], 2J[36 Hz, 30 Hz],
3J[94 Hz, 79 Hz] and 11 1J[476 Hz], 2J[36 Hz], 3J[97 Hz] suggested
skew trapezoidal geometries [32,33]. These coupling constant val-
ues and bond angles show that weaker interactions among the
atoms appeared in crystalline state are broken down in solution
state.
protons of triphenyltin(IV)
multiplets.
7 and 14 were also marked as
In 13C NMR of complexes (1–14), carboxylate moiety appears at
downfield shift due to coordination with metal atom. The com-
pounds 2 and 10 exhibit pair wise signals of Et–Sn and Bu–Sn moi-
eties with upfield shift for exocyclic and downfield shift for
endocyclic alkyl groups [27–29]. A single signal for carboxylate
moiety is obviously due to fluxional behaviour of this group [30].
There may be a fast exchange in coordination behaviour of carbox-
ylate moiety around endo- and exocyclic tin atoms. The coupling
satellites in 13C NMR are also important indicators for structural
evaluation of organotin carboxylates. nJ[119Sn, 13C] values mea-
sured for trimethyltin(IV) (5) 1J[376/394 Hz], (12) 1J[374/396 Hz],
tri-n-butyltin(IV) (6) 1J[344/351 Hz], 2J[34], 3J[92], (13) 1J[372/
386 Hz], 2J[29], 3J[97] and triphenyltin(IV) (7) 1J[645/663], 2J[46],
3J[61], (14) 1J[649/664], 2J[42], 3J[70] were characteristic of four
coordination [31]. nJ[119Sn, 13C] values measured for compounds
119Sn NMR spectra of all compounds were recorded and given in
experimental section. However, d(119Sn) is influenced by several
factors yet it may be used with confidence to infer the coordination
number around tin atom [34]. The compounds 1, 3, 4, 8, 9 and 11
exhibit single resonances at ꢁ136.9, ꢁ150.3, ꢁ163.7, ꢁ128.4,
ꢁ156.5 and ꢁ163.7 ppm, respectively, characteristic of penta-coor-
dinated tin atom as earlier reports manifested [34–38]. Trimethyl-
tin ( 5, 12), tri-n-butyltin (6, 13) and triphenyltin ( 7, 14)
compounds have single peaks in the region for tetrahedral com-
pounds [39–40]. For compounds (2) and (10), two isotropic 119Sn
resonances were observed (ꢁ211.8, ꢁ163.3 ppm) and (ꢁ196.5,
1
1J[645 Hz], 1J[607 Hz, 584], 2J[58, 49 Hz], 1J[569 Hz],
2 3
Fig. 3. Ortep diagram of compound (2) with numbering scheme.
Fig. 4. Ortep diagram of compound (10) excluding hydrogen atoms.

32
Aziz-ur-Rehman et al. / Inorganica Chimica Acta 370 (2011) 27–35
Table 3
Antibacterial activitya,b of organotin(IV) derivatives (1–14) of ligand acids.
Name of bacterium
Zone of inhibition (mm)
Ref. drug
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
Escherichia coli
Bacillus subtilis
Shijella flexenari
Pseudomonas aeruginosa
Staplococcus aureus
Salmonella typhi
10
18
15
16
11
8
14
7
8
12
11
10
7
9
13
7
9
8
16
15
14
10
11
8
14
19
16
11
10
8
14
8
14
10
10
13
12
11
18
9
13
10
14
11
12
18
15
35
38
32
38
29
28
7
11
6
15
14
9
8
14
12
12
8
11
18
5
10
9
8
10
12
15
16
a
In vitro, agar well diffusion method, concentration 3 mg/mL of DMSO.
Reference drug = Imipenum.
b
Table 4
Antifungal activitya,b,c,d data of organotin(IV) derivatives (1–14) of ligand acids.
Fungus
Zone of inhibition (mm)
Standard drug
MIC (lg/mL)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
T. longifusus
C. albicans
A. flavus
M. canis
F. solane
17
32
52
67
28
26
22
41
38
38
45
32
35
35
24
32
18
35
90
81
100
85
34
27
97
92
81
74
90
65
94
82
90
85
80
67
30
30
25
34
41
79
45
94
100
74
80
90
100
92
92
60
40
65
50
90
Miconazole
Miconazole
Amphotericin-B
Miconazole
Miconazole
Miconazole
70
110.8
20
98.4
73.25
110.8
45
62
48
22
40
46
15
45
30
46
43
27
40
35
42
31
40
C. glaberata
a
b
c
Concentration: 100 lg/mL of DMSO.
MIC: minimum inhibitory concentration.
Percent inhibition (standard drug) = 100.
% Inhibition = 100.
d
ꢁ200.1 ppm), respectively. The broadness of endo 119Sn peaks and
shift of frequency in compound (2) is indicative of a dynamic
behaviour of endocyclic tin atom. The difference of exo- and endo-
cyclic d values (49 ppm) is very small. However, it points toward
trapezoidal geometry around endocyclic tin while exocyclic tin
atom gives trigonal bipyramidal geometry. The resonances of
Bu2Sn are in the range for penta coordination around endo- and
exocyclic tin atoms. These values are in agreement with the litera-
ture values reports for similar distannoxanes [30,41].
groups at axial and four oxygen atoms of carboxylate moiety at
plan positions. Seventh position is occupied by bridging oxygen
atom of adjacent molecule connected by weaker Snꢀ ꢀ ꢀO interac-
tions. The C–Sn–C angle is 163.0° showing that enough space is
available around tin for further coordination [42,43]. Two ligands
are coordinated to Sn atom in bidentate fashion with tin-oxygen
bonds [(Sn(1)–O(1) = 2.438, Sn(1)–O(2) = 2.204 Å) and (Sn(1)–
O(3) = 2.346, Sn(1)–O(4) = 2.211 Å)]. Two molecular units are
interconnected with each other by bridging of oxygen atoms with
Sn moiety of neighbouring molecule having Snꢀ ꢀ ꢀO distance
(2.657 Å). Although these interactions are weaker than sum of
covalent radii (2.13 Å) and not considered in many cases but these
are stronger than Van der Waal’s radii (3.68 Å) and can be reported
confidently [17].
3.3. X-ray crystallographic studies
The molecular structure of compound (1) with intermolecular
interactions is given in Figs. 1 and 2 while selected geometric
parameters, bond lengths and bond angles are summarized in
Tables 1 and 2. The compound is dimeric and geometry around
Sn appears as distorted pentagonal bipyramidal with methyl
The solid state structure of 2 is depicted in Fig. 3 and inter-
atomic parameters are given in Tables 1 and 2. It is tetranuclear
centro symmetric dimer of oxoditin unit having central four mem-
Table 5
Brine shrimp lethality bioassay of organotin(IV) derivatives (1–14) of ligand acids.
Compound no.
LD50 g/mL)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(
l
35.4
10.8
6.3
5.9
25.8
68.4
12.6
7.9
3.62
5.85
Against brine-shrimps (in vitro).
Standard drug etoposide LD50 7.46 lg/mL.
Table 6
Insecticidal bioassay of organotin(IV) (1–14) derivatives of ligand acid.
Insecticides
% Mortality
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
Tribolium castaneum
Sitophilus oryzae
Rhyzopertha dominica
Callosbruchus analis
2
2
4
6
3
2
6
8
4
3
5
8
4
4
6
2
10
3
4
8
6
4
8
43
10
14
10
22
10
45
8
17
11
11
16
8
9
7
7
16
7
16
22
10
+ve control = 100%, ꢁve control = 0%, reference drug = Permethrin.

Aziz-ur-Rehman et al. / Inorganica Chimica Acta 370 (2011) 27–35
33
bered ring composed of Sn(1)–O(1)–Sn(1A)–O(1A). The geometry
around endo- and exocyclic tin atoms varies between six and five
coordination which is probably due to intra-molecular interactions
between the atoms. In this compound, central Sn2O2 core is fused
with two four-membered and two six membered rings. The four
membered rings [Sn2O2, i.e., O(1)–Sn(2)–O(7)–Sn(1A) and O(1A)–
Sn(2A)–O(7A)–Sn(1)] are due to the bridging of monodentate li-
gand through oxygen atoms O(7)–Sn(1A) and O(7A)–Sn(1), respec-
tively. Although, the Snꢀ ꢀ ꢀO distance for these interactions is quite
longer (2.76 Å) than sum of covalent radii of tin-oxygen atoms
(2.13 Å) yet significantly shorter than sum of Van der Waal’s radii
of these atoms (3.68 Å) [33]. If these weaker interactions are taken
into consideration, the geometry around endocyclic tin atoms
looks like skew trapezoidal with three Sn–O bonds and two
Sn–C covalent interactions. Sixth position is occupied by weaker
Sn–O interaction. The axial C–Sn–C angle [C(25)–Sn(2)–
C(29) = 147.5(4)°] deviates from ideal value (180°) and it shows
that adequate space is available for equatorial ligands to coordi-
nate with metal atom [44]. Two six membered rings [Sn2O3C, i.e.,
Sn(1)–O(6)–C(1)–O(3)–Sn(2)–O(1), Sn(1A)–O(6A)–C(1A)–O(3A)–
Sn(2A)–O(1A)] also overlap central Sn2O2 The exocyclic tin atoms
show trigonal bipyramidal environment arranged by two carbon
atoms and three oxygen atoms. In crystal structure of di-n-butyltin
(10) (Fig. 4), One of the carboxylate ligand is attached to both
endocyclic [(Sn(2)–O(8) = 2.276 Å] and exocyclic tin atoms
[(Sn(2)–O(8) = 2.276 Å] have equal Sn–O interactions while second
shows unidentate behaviour. The C–Sn–C angles around endocyclic
[C(23)–Sn(2)–C(27) = 136.7(4)°] and exocyclic tin [C(15)–Sn(1)–
C(19) = 144.3(4)°] atoms show that distortion around endocyclic
tin atoms is relatively higher than exocyclic tin atoms. The weak
Snꢀ ꢀ ꢀO interaction [Sn(1)ꢀ ꢀ ꢀO(9) = 2.913 Å], is however, close to
that calculated for compound (2) but relatively weaker than previ-
ous one. In this view, the geometry around endocyclic tin atom can
be suggested as trigonal bipyramidal with high distortion. Crystal
structure of compound (7) has been reported [45] earlier by our
group.
4. Biological studies
4.1. Antibacterial activity
The synthesized compounds (1–14) were tested for their
antibacterial activity against six bacterial strains, Escherichia coli,
Bacillus subtilis, Shigella flexenari, Pseudomonas aeruginosa, Staphylo-
coccus aureus, Salmonella typhi, using agar well diffusion method
[46] and data are listed in Table 3. It is observed that all com-
pounds have shown activity against all strains with few excep-
tions. According to earlier reports [35,36], triorganotin(IV) are
more active than the corresponding diorganotin(IV) compounds
but a mixed behaviour is observed during this study and sequence
varies from strain to strain. However, phenyl derivatives in triorga-
notin(IV) compounds are found more active than their analogues
and butyltin(IV) compounds in diorganotins(IV) stood before
methyl and ethyltin(IV) derivatives. This may be due to high lipo-
philic character of these moieties. The high activity of methyl-
tin(IV) derivatives in some cases can be explained on the basis of
ease of diffusion of these compounds through cell membrane due
to their smaller size.
4.2. Antifungal activity
The reported compounds (1–14) were tested for their antifungal
activity against six strains, Trichophyton longifusus, Candida
albicans, Aspergillus flavus, Microsporum canis, Fusarium solane, Can-
dida glaberata using the agar well protocol [46] and data are listed

34
Aziz-ur-Rehman et al. / Inorganica Chimica Acta 370 (2011) 27–35
in Table 4. All derivatives, in general, showed markedly higher
antifungal activity than the ligand with few exceptions. Triorgano-
tin(IV) derivatives were found more active than the diorganotin
derivatives, a behaviour quite consistent with the earlier report
[47].
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.ica.2011.01.007.
References
[1] A. Orita, K. Sakamoto, Y. Hamada, A. Mitsutome, J. Otera, Tetrahedron 55
(1999) 2899.
4.3. Cytotoxicity
[2] D. Seyferth, T.C. Masterman, Appl. Organomet. Chem. 8 (4) (1994) 335 (and
references therein).
[3] A.A. Mahmoud, A.F. Shaaban, M.M. Azab, N.N. Messiha, Eur. Poylm. J. 28 (1992)
555.
[4] J.R. Dharia, C.P. Pathak, G.N. Babu, S.K. Gupta, J. Polym. Sci. 26 (1988) 595.
[5] M. Gielen, A.G. Davies, K. Pannell, E.R.T. Tiekink (Eds.), Tin Chemistry:
Fundamentals, Frontiers and Applications, Wiley, 2008.
[6] J.K. Tsagatakis, N.A. Chaniotakis, K. Jurkschat, S. Damoun, P. Geerlings, A.
Bouhdid, M. Gielen, I. Verbruggen, M. Biesemans, J.C. Martins, R. Willem, Helv.
Chim. Acta 82 (1999) 531.
Compounds were also screened for cytotoxic data, using Brine-
shrimp (Artemia salina) bioassay lethality method [46,48] and re-
sults are shown in Table 5. The data illustrate that compounds
(1), (4), (5) and (14) show no cytotoxicity. However, the LD50 value
for Bu3Sn and Ph3Sn (7), derivatives is comparable with standard
drug whereas compounds 2, 3, 8, 9 and 10 were found more cyto-
toxic than the standard drug.
[7] S. Mahmood, S. Ali, M.H. Bhatti, M. Mazhar, K. Shahid, Turk. J. Chem. 28 (2004)
17.
4.4. Insecticidal activity
[8] S. Rehman, K. Shahid, S. Ali, M.H. Bhatti, M. Parvez, J. Organomet. Chem. 690
(2005) 1396.
[9] M. Gielen, E.R.T. Tiekink, in: M. Gielen, E.R.T. Tiekink (Eds.), Metallotherapeutic
Drug and Metal-based Diagnostic Agents: 50Sn Tin Compounds and Their
Therapeutic Potential, Wiley, 2005.
[10] L. Tian, Y. Sun, H. Li, X. Zheng, Y. Cheng, X. Liu, B. Qian, J. Inorg. Biochem. 99
(2005) 1646.
Four insecticides Tribolium castaneum, Callosobruchus analis,
Sitophilus oryzae and Rhyzopartha dominica were used for insecti-
cidal activity. The activities were determined by direct contact
application using filter paper [49]. The reference drug used was
[11] M. Gielen, J. Braz. Chem. Soc. 14 (2003) 870.
Permethrin (235.71 l
g/cm2) (Table 6). All compounds were found
[12] M. Gielen, K. Handlir, M. Hollein, D. De, Vos. Met. Based Drugs. 7 (2000) 233.
[13] Imtiaz-ud-Din, M. Mazhar, K.M. Khan, M.F. Maohon, K.C. Molloy, J. Organomet.
Chem. 689 (2004) 899.
active but the mortality rate is less than reference insecticidal drug.
[14] A.G. Davies, P.J. Smith, Adv. Inorg. Chem. 23 (1980) 1.
[15] W.N. Aldridge, in: J.J. Zuckerman (Ed.), Organotin Compounds. New Chemistry
and Applications, Am. Chem. Soc, Washington, 1976.
4.5. Urease inhibition activity
[16] B.M. Elliot, W.N. Aldridge, J.M. Bridges, Biochem. J. 177 (1979) 461.
[17] M. Hanif, M. Hussain, S. Ali, M.H. Bhatti, M.S. Ahmed, B. Mirza, H.S. Evans,
Polyhedron 29 (2010) 613.
[18] N. Muhammad, Zia-ur-Rehman, S. Ali, A. Meetsma, F. Shaheen, Inorg. Chim.
Acta 362 (2009) 2842.
[19] Zia-ur-Rehman, M.M. Barsan, I. Wharf, N. Muhammad, S. Ali, A. Meetsma, Ian
S. Butler, Inorg. Chim. Acta 361 (2008) 3322.
[20] Aziz-ur-Rehman, M. Hussain, Zia-ur-Rehman, A. Rauf, F.H. Nasim, A.A. Tahir,
S. Ali, J. Organomet. Chem. 695 (2010) 1526.
[21] D.D. Perrin, W.L.F. Armengo, Purification of Laboratory Chemical, third ed.,
Pergamon Press, Oxford, 2003.
[22] M.K. Rauf, M.A. Saeed, Imtiaz-ud-Din, M. Bolte, A. Badshah, B. Mirza, J.
Organomet. Chem. 693 (2008) 3043.
[23] N. Muhammad, A. Shah, Zia-ur-Rehman, S. Shuja, S. Ali, R. Qureshi, A.
Meetsma, M.N. Tahir, J. Organomet. Chem. 694 (2009) 3431.
[24] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination
Compounds, fourth ed., Wiley, New York, 1980.
[25] D. Kovala-Demertzi, V.N. Dokorou, J.P. Jasinski, A. Opolski, J. Wiecek, M.
Zervou, M.A. Demertzis, J. Organomet. Chem. 690 (2005) 1800.
[26] Zia-ur-Rehman, N. Muhammad, S. Shuja, S. Ali, I.S. Butler, A. Meetsma, M.
Khan, Polyhedron 28 (2009) 3439.
Antiurease inhibition activity was tested by reported protocol
[50] using thiourea as a standard inhibitor and results are given
in Table 7. All tested compounds demonstrated fairly good inhibi-
tion even at micromolar level. Among these, the most promising
activity was noted for alkyltin(IV) derivatives (1 and 2) and phen-
yltin(IV) derivative (7 and 14). This can be attributed to the ability
of these compounds to establish secondary interactions with the
active site of enzyme, i.e., nickel. The relatively less activity in case
of di-n-butyltin (3, 10), di-n-octyltin (4, 11) and tri-n-butyltin (6,
13) derivatives is presumably due to bulky alkyl group that hinder
such kind of interaction of the ligand moiety with enzyme.
5. Conclusions
New mononuclear, dinuclear and tetranuclear organotin(IV)
derivatives of substituted carboxylate ligands have been synthe-
sized and structurally characterized by various spectroscopic
techniques and X-ray crystallography. The later technique authen-
ticated the dinuclear and tetranuclear nature of compounds 1, 2
and 10, respectively. The compound 1 is of particular interest be-
cause each Sn atom has pentagonal bipyramidal geometry with
one bidentate ligand attached is acting as a bridging one as well.
All compounds have been seen biologically active. However, it is
observed during biological testing that major role is attributed to
the alkyl/aryl groups attached to tin atom while ligands play sec-
ondary role.
ˇ
ˇ
ˆ
[27] J. Holecek, M. Nádvornik, K. Handlir, A. Lycka, J. Organomet. Chem. 315 (1986)
299.
ˇ
ˆ
[28] M. Nádvornik, J. Holecek, K. Handli⁄, A. Lycka, J. Organomet. Chem. 275 (1984)
43.
[29] M. Gielen, J. Meunier-Piret, M. Bieseman, R. Willem, Appl. Organomet. Chem. 6
(1992) 59.
[30] M. Yoshifuji, S. Ito, K. Toyota, M. Yasunami, Heteroat. Chem. 7 (1996) 23.
[31] G. Casella, F. Ferrante, G. Saielli, Inorg. Chem. 47 (2008) 4796.
[32] M. Danish, H.G. Alt, A. Badshah, S. Ali, M. Mazhar, N. Islam, J. Organomet.
Chem. 486 (1995) 51.
[33] Imtiaz-ud-Din, M. Mazhar, K.C. Molloy, K.M. Khan, J. Organomet. Chem. 691
(2006) 1643.
[34] M. Hussain, M. Hanif, S. Ali, M.H. Bhatti, M.S. Ahmad, B. Mirza, H.S. Evans, Turk.
J. Chem. 31 (2007) 349.
[35] M.S. Ahmad, M. Hussain, M. Hanif, S. Ali, M. Qayyum, B. Mirza, Chem. Biol.
Drug Des. 71 (2008) 568.
Acknowledgements
[36] M.S. Ahmad, M. Hussain, M. Hanif, S. Ali, B. Mirza, Molecule 12 (2007) 2348.
[37] M. Hussain, M. Hanif, S. Ali, S. Shahzadi, H.S. Evans, Turk. J. Chem. 32 (2008) 25.
[38] M. Hanif, M. Hussain, S. Ali, M.H. Bhatti, H.S. Evans, Anal. Sci. 23 (2007) x165.
[39] B. Wrackmeyer, Annu. Rep. NMR Spectrosc. 16 (1985) 73.
[40] B. Wrackmeyer, Annu. Rep. NMR Spectrosc. 38 (1999) 203.
[41] M.H. Bhatti, S. Ali, F. Huma, S. Shahzadi, Turk. J. Chem. 29 (2005) 463.
[42] S.W. Ng, C. Wei, V.G.K. Das, T.C.W. Mak, J. Organomet. Chem. 334 (1987) 295.
[43] S.G. Teoh, S.H. Ang, J.P.D. Declercq, Polyhedron 16 (1997) 3729.
[44] V.N. Dokorou, D.K. Demertzi, M. Louloudi, A. Silvestru, M.A. Demertzis, J.
Organomet. Chem. 693 (2008) 3587.
We thank the Higher Education Commission of Pakistan for
financial support.
Appendix A. Supplementary material
CCDC 760097, 760094 and 760095 contain the supplementary
crystallographic data for complexes 1, 2 and 10, respectively. These
data can be obtained free of charge from The Cambridge Crystallo-
graphic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
[45] S. Aziz-ur-Rehman, S. Ali, M. Shahzadi, Acta Crystallogr., Sect. E: Struct. Rep.
Online E63 (2007) m746.
[46] A. Rahman, M.I. Choudry, W.J. Thomsen, Bioassay Techniques for Drug
Development, Harwood, The Netherlands, 2001.

Aziz-ur-Rehman et al. / Inorganica Chimica Acta 370 (2011) 27–35
35
[47] C.C. Camacho, D. de Vos, B. Mahieu, M. Gielen, M. Kemmer, M. Biesemans, R.
Willem, Main Group Met. Chem. 23 (2000) 381.
[48] B.N. Meyer, N.R. Ferrigni, J.E. Putnam, L.B. Jacobsen, D.E. Nichols, J.L.
McLaughlin, Planta Med. 45 (1982) 31.
[49] Y.J. Ahn, G.H. Kim, K.Y. Cho, in: Proceedings of the Third Symposium on the
Biochemical Methodology for the Research and Development of the Bioactive
Substances, Seoul, 1995.
[50] M.W. Weatherburn, Anal. Chem. 39 (1967) 971.