Synthesis, structures and in vitro antitumor activity of some germanium-substituted di-n-butyltin dipropionates

Article abstract of DOI:10.1016/S0022-328X(98)00607-X

Sixteen new germanium-substituted di-n-butyltin dipropionates with the form (R₃GeCHR²CHR¹COO)₂SnBu ₂ⁿ.H₂O (R₃=Ph₃, N(OCH₂CH₂)₃

Full text of DOI:10.1016/S0022-328X(98)00607-X

Journal of Organometallic Chemistry 566 (1998) 103–110
Synthesis, structures and in vitro antitumor activity of some
germanium-substituted di-n-butyltin dipropionates
Song Xueqing *, Yang Zhiqiang, Xie Qinglan, Li Jinshan
National Laboratory of Elemento-Organic Chemistry, NanKai Uni6ersity, Tianjin, 300071, People’s Republic of China
Received 20 February 1998
Abstract
Sixteen new germanium-substituted di-n-butyltin dipropionates with the form (R3GeCHR2CHR1COO)2SnBu2n.H2O (R3=Ph3,
N(OCH2CH2)3; R2=H,CH3, Aryl; R1=H,CH3) were synthesized and characterized by IR, NMR (1H, 119Sn) and MS
n
spectroscopy, and in the case of Bu2Sn[O2CCH2CH(4-Cl-C6H4)Ge(OCH2CH2)3N]2.H2O by X-ray diffraction study. The in vitro
antitumor activity of some selected derivatives against KB cells, HCT-8 cells and Bel7402 cells is presented. © 1998 Elsevier
Science S.A. All rights reserved.
Keywords: di-n-Butyltin dipropionates; Infrared spectroscopy; Crystal structure; Antitumor activity
nBu2SnO+2HO2CCHR1CHR2GeR3
1. Introduction
“nBu2Sn(O2CCHR1CHR2GeR3)2.H2O
The study of organotin compounds is of current
interest owing to their wide range of applications [1–4]
such as biocides and as homogeneous catalysts in in-
For compounds I, R3=(OCH2CH2)3N, R1=H, and
R2 is: H (I1); CH3 (I2); C6H5 (I3); 4-ClC6H4 (I4); 2-
ClC6H4 (I5); 4-CH3C6H4 (I6); 2-CH3C6H4 (I7); 2,4-
dustry. Recently, the potential antitumor activity of
Cl2C6H3 (I8); 4-CH3OC6H4 (I9); 4-NO2C6H4 (I10);
diorganotin carboxylates has been widely studied [5].
R1=CH3, R2=H (I1l). For compounds II, R3=Ph3,
As we know very well, organogermanium is another
R1=H, and R2 is: CH3 (II1); C6H5 (II2); 4-ClC6H4 (II3);
kind of element that has a wide range of biological
4-CH3C6H4 (II4); 4-CH3OC6H4 (II5).
activity [6]. Therefore, we here prepared 16 new germa-
nium-substituted di-n-butyltin dipropionates in order to
examine whether including germanium into the
diorganotin compounds improves their antitumor prop-
2. Experimental section
erties. In parallel, we were also interested in studying
the nature of bonding and structure of these
2.1. Instruments
compounds.
IR spectra were recorded on a Shimadzu IR-435
These germanium-substituted di-n-butyltin dipropi-
onates were synthesized by the condensation of di-n-
spectrometer in KBr discs. The 1H-NMR and 119Sn-
NMR spectra were measured on a JEOL-FX-90Q spec-
butyltin oxide and germanium-substituted propionic
trometer with TMS as internal and Me4Sn as external
acids in the molar ratio 1:2. The general reaction
standard. Elemental analyses were determined on an
MT-3 elemental analyzer. Mass spectra were recorded
scheme is shown as following:
on an HP-5988A at 70 ev, the temperature of ionization
* Corresponding author.
was 200°C.
0022-328X/98/$19.00 © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00607-X

104
S. Xueqing et al. / Journal of Organometallic Chemistry 566 (1998) 103–110
Table 2
IR data of carbonyl groups of nBu2Sn(O2CCHR1CHR2GeR3)2.H2O
(cm−1
)
Compound
 asym
 sym
D 

H–O–H
I1
1623
1552
1631
1562
1631
1559
1638
1562
1627
1566
1635
1558
1605
1563
1604
1595
1578
1592
1591
1595
1578
1590
1614
1379
1407
1366
1398
1361
1404
1366
1398
1339
1401
1337
1380
1331
1397
1389
1395
1382
1378
1384
1382
1366
1379
1376
244
145
259
156
270
155
272
164
288
165
298
188
274
166
215
200
196
214
207
213
212
211
238
3357
3382
3396
3401
3386
3400
3394
I6
I7
I9
I10
II3
II5
Scheme 1.
I11
I2
I3
I4
I5
3377
3362
3394
3385
3382
3403
3388
3406
3400
2.2. Synthesis
Di-n-butyltin oxide was prepared by alkaline hydrol-
n
I8
ysis of Bu2SnCl2, and the germanium-substituted pro-
II1
II2
II4
pionic acids were prepared according to earlier
reference [7] (see Scheme 1).
The synthesis of compounds I and II is analogous to
that of diorganotin dicarboxylates. Typically, 0.005 mol
di-n-butyltin oxide was suspended in a solution of 0.01
mol of the appropriate substituted propionic acid in
200 ml of toluene and refluxed for 6 h, one half of the
solvent was distiled off with a Dean–Stark apparatus.
The remaining homogeneous solution was then cooled
off and filtered. The solvent was evaporated under
vacuum. The obtained solid was recrystallized from
solvent mixture CHCl3/petroether. The yields, physical
states, melting points and elemental analyses of the
prepared compounds are given in Table 1.
2.3. Crystal structure determination
Intensity data for colorless crystal (0.25×0.3×0.3
n
mm) of Bu2Sn[O2CCH2CH(4-ClC6H4)Ge(OCH2CH2)3
N]2.H2O were measured at 299 K on an Enraf-Nonius
CAD4F diffractometer fitted with graphite-monochro-
matized Mo–Kh radiation. u=0.71073. The ꢀ:2q scan
technique was employed to measure 3319 data up to a
maximum Bragg angle of 23°. The data set was cor-
rected for Lorentz and polarization effects and for
Table 1
The yields and elemental analyses of nBu2Sn(O2CCHR1CHR2GeR3)2.H2O
Number Physical state
MW
832.57
860.87
984.77
Yield (%)
Mp. (°C)
(C%) Analysis
(H%) Elemental
(N%) Found (Calcd.)
I1
White crystal
White crystal
White crystal
White crystal
White crystal
White crystal
White crystal
White crystal
White crystal
White crystal
White crystal
White crystal
White crystal
White crystal
White crystal
White crystal
91.7
89.3
93.5
71.2
88.4
76.4
84.5
91.5
90.3
87.3
80.6
87.6
80.9
82.5
85.4
76.1
152–154
164–166
236–239
241–243
218–220
240–242
245–246
217–219
223–225
244–246
187–189
119–121
150–153
153–155
96–98
37.88(37.51)
39.45(39.07)
46.78(46.35)
43.40(43.16)
43.63(43.16)
40.57(40.66)
47.59(47.43)
47.81(47.43)
46.90(46.80)
41.48(41.24)
39.51(39.07)
60.69(60.58)
64.75(64.47)
65.26(64.97)
63.29(63.27)
61.35(60.86)
6.22(6.30)
6.42(6.56)
5.54(6.14)
5.55(5.52)
5.40(5.52)
5.04(5.03)
6.49(6.17)
6.54(6.17)
6.30(6.09)
5.12(5.28)
6.09(6.56)
6.15(6.06)
5.60(5.76)
6.01(5.90)
5.82(5.64)
5.34(5.27)
3.16(3.36)
3.35(3.26)
2.78(2.84)
2.68(2.65)
2.80(2.65)
2.08(2.50)
2.32(2.77)
2.75(2.77)
2.86(2.73)
4.60(5.06)
3.20(3.26)
I2
I3
I4
I5
I6
I7
I8
I9
1053.66
1053.66
1122.55
1012.82
1012.82
1044.82
1106.42
860.87
1030.93
1155.07
1223.96
1183.13
1114.86
I10
I11
II1
II2
II3
II4
II5
161–163
For compounds of type I, R3=(OCH2CH2)3N; for compounds of type II, R3=Ph3.

S. Xueqing et al. / Journal of Organometallic Chemistry 566 (1998) 103–110
3. Results and discussion
105
3.1. IR data
The infrared spectra of these compounds have been
recorded in the range of 4000–400 cm−1. Tentative
assignments have been made on the basis of earlier
publications and important data are listed in Table 2.
The absorptions of interest are those of carbonyl CꢀO,
Sn–C, Sn–O and H–O–H bonds. In the spectra,
medium to weak bands in the region 430–480 cm−1 are
assigned to Sn–O [8]; those in the region 500–600
cm−1 indicate the presence of Sn–C bonds [9]. As there
are wide and strong absorptions around 3400 cm−1, we
assume that there may be a water molecule in the
product [10].
Scheme 2.
We know very well that there are mainly three kinds
of structures for trialkyltin carboxylates [11]: the four-
coordinate structure for the monomers (A) and the
five-coordinate structure (B) for monomers and (C) for
polymers (see Scheme 2).
The vacant 5d orbitals on tin atoms tend towards
high-coordination with ligands containing lone electron
pairs. The IR stretching vibration frequencies of car-
bonyl groups in organotin carboxylates are important
for determining their structures: when the structure
changes from A to B or C, the asymmetric absorption
vibration frequencies ( asym) of carbonyl groups de-
crease and the symmetric absorption vibration frequen-
cies ( sym) increase. The difference (D CꢀO) therefore
decreases.
The carbonyl absorptions of diorganotin carboxy-
lates are apparently more complicated than those of
trialkyl carboxylates, because there are two carbonyl
groups. Therefore, if the two carbonyl groups have the
same coordination environment, there is only one car-
bonyl absorption in the IR spectra; if there are two
carbonyl absorptions in the spectra, the two carbonyl
groups have different coordination environments [12].
We see from Table 2 that there are two types of
carbonyl absorption in the list, one type has two car-
bonyl absorptions, and the other has only one. This
suggests three types of structure for these compounds.
Those of the di-n-butyltin dipropionates which have
only one carbonyl absorption is illustrated as A, includ-
ing the possibility of having a water molecule in the
structure. Those having two carbonyl absorptions may
be illustrated as B (intramolecular coordination) and C
(intermolecular coordination) (see Scheme 3).
absorption using an analytical procedure, maximum
and minimum transmission factors were 0.641 and
0.591, respectively. There were 2760 independent reflec-
tions of which 1819 satisfied the I]3|(I) criterion and
were used in the subsequent analysis.
Crystal data for nBu2Sn[O2CCH2CH(4-ClC6H4)Ge-
(OCH2CH2)3N]2.H2O: monoclinic, space group C/2c,
˚
˚
˚
a=21.182(5) A, b=12.174(3) A, c=17.108(4) A, i=
99.59(2)°, V=4350(3) A , Z=4, Dcalc. =1.581mg m−3
,
3
˚
F(000)=2104, v=2.104 mm−1
.
The structure was solved from the interpretation of
the patterns on synthesis and refined by a full-matrix
least squares procedure based on F. Non-hydrogen
atoms were refined with anisotropic thermal parame-
ters. Hydrogen atoms were not included in the model.
The refinement was continued with sigma weights until
R=0.045 and Rw=0.055. The maximum residual elec-
tron density peak in the final difference map was 0.54
eA−3. Final fractional atomic coordinates for the hy-
˚
drogen atoms are listed in Table 8.
1
3.2. H-NMR
1
The H-NMR data of compounds II are presented in
Table 3, and those of compounds I in Table 4. The
butyltin derivatives show a multiplet in the region
0.68–1.48 ppm for butyl protons with a well defined
Scheme 3.

106
S. Xueqing et al. / Journal of Organometallic Chemistry 566 (1998) 103–110
Table 3
Main 1H-NMR data of nBu2Sn(O2CCHR1CHR2GePh3)2.H2Oa (ppm)
Number l1H
CH3
(CH2)3
CH2
CH
R2
Ph
II1
II2
II3
II4
II5
0.83(6H,t)
0.72(6H,t)
0.73(6H,t)
0.68(6H,t)
0.68(6H,t)
1.10–1.40(12H,m)
1.04–1.28(12H,m)
1.04–1.28(12H,m)
0.96–1.28(12H,m)
0.98–1.28(12H,m)
2.40–2.60(4H,m)
2.96(4H,d)
2.94(4H,d)
2.95(4H,d)
2.96(4H,d)
2.20–2.40(2H,m)
3.72(2H,t)
3.58(2H,t)
3.64(2H,t)
3.62(2H,t)
1.60(6H,d)
6.80–7.20(10H,m)
6.62–7.00(8H,dd)
6.68–7.02(8H,dd) 2.27(6H,s)
6.60–6.94(8H,dd) 3.76(6H,s)
7.28(30,s)
7.35(30,s)
7.22(30,s)
7.36(30,s)
7.38(30,s)
a R1=H.
Table 4
Main 1H-NMR data for nBu2Sn[O2CCHR1CHR2Ge(OCH2CH2)3N]2.H2O (ppm)
Number l1H
CH3
(CH2)3
R2(R1)
CH and CH2
2.60(4H,t)
N(CH2)3
(OCH2)3
I1
I2
I3
I4
I5
I6
I7
I8
I9
I10
I11
0.87(6H,t) 1.12–1.48(12H,m)
0.90(6H,t) 1.14–1.48(12H,m)
0.78(6H,t) 1.04–1.46(12H,m)
0.78(6H,t) 1.06–1.34(12H,m)
0.78(6H,t) 1.02–1.36(12H,m)
0.76(6H,t) 0.98–1.20(12H,m)
0.78(6H,t) 0.96–1.18(12H,m)
0.76(6H,t) 0.96–1.18(12H,m)
0.78(6H,t) 1.02–1.22(12H,m)
0.64–1.60(18H,m)
1.64(4H,t)
2.84(12H,t) 3.78(12H,t)
2.80(12H,t) 3.78(12H,t)
2.78(12H,t) 3.76(12H,t)
2.76(12H,t) 3.72(12H,t)
2.78(12H,t) 3.74(12H,t)
2.77(12H,t) 3.79(12H,t)
2.78(12H,t) 3.76(12H,t)
2.78(12H,t) 3.78(12H,t)
2.78(12H,t) 3.77(12H,t)
2.76(12H,t) 3.64(12H,t)
2.82(12H,t) 3.80(12H,t)
1.26(6H,d)
1.64–1.78(2H,m) 2.65–2.86(4H,m)
7.04–7.44(10H,m)
7.04–7.40(8H,m)
6.94–7.60(8H,m)
7.00–7.48(6H,m)
7.00–7.16(8H,dd),2.24(6H,s) 3.00(6H,s)
7.00–7.46(8H,m),2.36(6H,s) 3.08(6H,s)
6.76–7.38(8H,dd),3.78(6H,s) 3.00(6H,s)
3.04(6H,s)
3.00(6H,s)
3.04(6H,s)
3.06(6H,s)
7.35–7.98(8H,m)
3.04(6H,s)
2.72–2.86(2H,m) 1.70(4H,t)
0.92(6H,t) 1.12–1.44(12H,m)
1.28(6H,d)a
For compound I1 to I10, R1=H; for compound I11, R2=H.
a R1=CH3.
Table 5
119Sn-NMR data for nBu2Sn(O2CCHR1CHR2GeR3)2.H2O(ppm) (CDCl3 as solvent)
I3
I4
I7
I9
I11
II1
II2
II3
II4
II5
l
119Sn
−150.7
−149.2
−200.9a
−151.4
−161.8
−146.4
−145.8
−144.6
−146.7
−146.8
a
CDCl3+DMSO-d6 as solvent.
triplet in the region 0.68–0.92 ppm, which may be due
to the terminal methyl protons [13]. From the table we
find that when one i proton is substituted with an aryl
group, there is a significant downfield shift for the h
and i protons due to the deshielding effects. Compare
1H-NMR spectra of N(CH2CH2O)3GeCHR2CHR1CO-
OH with that of its derivatives [N(CH2CH2O)3GeCHR2
CHR1CO2]2SnBu2n.H2O, we find an upfield shift for the
protons in N(CH2CH2O)3Ge moiety. Here C(1) is a
chiral center and C(2) is a prochiral center, and the
three hydrogens on C(1) and C(2) comprise an ABC
system. However, the ABC system can not be identified
in 90 MHz spectra. Here the three hydrogens show a
singlet in most cases. All the protons in the compounds
have been identified and the total number of protons
calculated from the integration curve tallies with what
was expected from the molecular formula.
3.3. 119Sn-NMR data
All the compounds selected for the 119Sn-NMR study
exhibit a single resonance in the region −140 to −165
ppm, except the compound I7, which is only poorly
soluble in CDCl3, and exhibits a single resonance in
DMSO-d6 at a much higher field (as shown in Table 5),
which may be attributed to the coordination of the
DMSO-d6 to tin atom [14]. Compared with previously
published results [15], the shift range of these com-
pounds looks more like pentacoordination. This sug-
gests that all appear to have the same structure

S. Xueqing et al. / Journal of Organometallic Chemistry 566 (1998) 103–110
107
Table 6
Main fragment ions observed for compounds I3 and II2
Compound I3
Compound II2
m/z
Fragment ion
Intensity
m/z
Fragment ion
Intensity
602
387
352
267
220
N(C2H4O)3GeCHPhCH2CO2S+nBu2
PhCHꢀCHCOOS+nBu2n
11
51.7
10.5
16
689
305
267
234
227
Ph3GeCH(C6H5)CH2CO2S+nBu2n
Ph3Ge+
3.9
100
5.7
7.4
8.3
N(C2H4O)GeCHPhCH2CꢁO+
PhCHꢀCHCOOS+n
PhCHꢁCHCOOS+n
nBu Sn+
’
2
N(CH2CH2O)3Ge+
100
177
147
121
120
103
nBuS+n
46
57
24.5
19.9
44
197
177
147
121
103
PhS+n
12.5
16.7
24.1
8.3
PhCHꢀCHCOO+
nBuS+n
HS+n
PhCHꢀCHCOO+
HSn+
Sn+
PhCHꢀ+CH
PhCHꢀ+CH
13.2
(possibly pentacoordinated geometry) in solution de-
spite differences in solid state.
3.5. Crystal structure of compound II4
The single crystal was recrystallized from CHCl3/
3.4. Mass spectra
petroether (90–120°C). The crystal structure was deter-
Table 8
Main fragment ions observed in the mass spectra of
compound I3 and II2 are listed in Table 6. The molecu-
lar ion is never observed but the fragment ions found
are in agreement with the expected structure of the
compounds. For both compounds, the ions containing
germanium (Ph3Ge+ or N(CH2CH2O)3Ge+) are the
base peaks, and other ions containing germanium are
also generally quite intense.
Fractional coordinates and thermal parameters of non-hydrogen for
compound Ia4
2
˚
Atom
x
y
z
Beq (A )
Sn(1)
Ge(1)
Cl(1)
C(1)
C(2)
O(1)
C(3)
C(4)
O(2)
C(5)
0.000
0.35506(8)
0.17496(8)
0.31079(3)
−0.017(1)
−0.0316(8)
0.0439(6)
0.117(1)
0.138(1)
0.1866(7)
0.146(2)
0.250
3.81(2)
3.80(2)
8.6(1)
8.8(4)
6.0(3)
6.5(2)
7.8(3)
6.3(3)
6.4(2)
11.5(5)
6.6(3)
6.5(2)
4.6(2)
4.7(2)
4.4(2)
65(2)
0.09966(5)
−0.2221(1)
0.1304
−0.08867(5)
−0.0946(2)
−0.1759(9)
−0.1482(7)
−0.0873(5)
−0.1596(8)
−0.0755(6)
−0.0413(4)
−0.2542(7)
−0.2396(6)
−0.1662(4)
−0.1831(4)
−0.0070(6)
−0.0275(5)
−0.0210(6)
−0.0400(6)
−0.0666(6)
−0.0718(6)
−0.0530(5)
0.0737(6)
0.0710(5)
0.0639(3)
0.2121(5)
0.2285(5)
0.1809(3)
0.1137(7)
0.0908(6)
0.0714(4)
0.1457(4)
0.0630(5)
−0.0101(5)
−0.0511(5)
−0.1162(4)
−0.1401(5)
−0.1012(5)
−0.0354(5)
0.0859(5)
0.0367(3)
0.0640(3)
0.0611(4)
0.4243(6)
0.3611(6)
0.6861(5)
0.2543(6)
Table 7
Selected bond distances and bond angles of compound I4a
C(6)
O(3)
0.260(1)
˚
0.2692(6)
0.0991(7)
0.2536(8)
0.2649(8)
0.1793(7)
0.1918(8)
0.2934(9)
0.3795(8)
0.3653(8)
0.208(1)
0.2240(5)
0.3750(6)
0.2741(8)
0.088(1)
0.066(1)
−0.013(1)
0.979(1)
Bond
Distances (A) Bond
Angles (°)
N(1)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(7)
O(5)
O(4)
C(8)
C(21)
C(22)
C(23)
C(24)
Sn(1)–O(5)
Sn(1)–O(5a)
Sn(1)–O(4)
Sn(1)–O(4a)
Sn(1)–C(8)
Sn(1)–C(8a)
Sn(1)–C(21)
2.099(6)
2.099(6)
2.518(5)
2.518(5)
2.659(8)
2.659(8)
2.10(1)
O(5)–Sn(1)–O(5a)
81.1(3)
55.0(3)
136.0(2)
27.8(2)
108.7(3)
106.5(3)
O(5)–Sn(1)–O(4)
O(5)–Sn(1)–O(4a)
O(5)–Sn(1)–C(8)
O(5)–Sn(1)–C(8a)
O(5)Sn(1)–C(21)
4.8(2)
4.8(2)
5.0(2)
4.7(2)
5.7(3)
4.5(1)
5.7(2)
4.3(2)
7.3(3)
6.4(3)
7.1(3)
8.5(4)
O(5)–Sn(1)–C(21a) 102.7(3)
Sn(1)–C(21a) 2.10(1)
O(5)–Sn(1)–O(6)
O(4)–Sn(1)–O(6)
C(21)–Sn(1)–C(21a) 141.2(6)
C(21)–Sn(1)–O(6)
Sn(1)–O(4)–C(8)
Sn(1)–O(4)–C(8)
139.5(1)
84.5(2)
0.1916(3)
0.1393(4)
0.1390(6)
0.6642(6)
0.6850(7)
0.3781(7)
0.6429(8)
Sn(1)–O(6)
Ge(1)–O(1)
Ge(1)–O(2)
Ge(1)–O(3)
Ge(1)–N(1)
C(8)–O(4)
C(8)–O(5)
2.54(4)
1.768(6)
1.781(5)
1.781(6)
2.222(6)
1.24(1)
1.27(1)
70.6(3)
82.7(5)
101.5(6)
a Numbers in parentheses are estimated standard deviations in the
least significant digits.
a Numbers in parentheses are estimated standard deviations in the
least significant digits.

108
S. Xueqing et al. / Journal of Organometallic Chemistry 566 (1998) 103–110
Fig. 1. Molecular structure and crystallographic numbering scheme for nBu2Sn[O2CCH2CH(4-ClC6H4)Ge(OCH2CH2)3N]2.H2O.
Fig. 2. Pentagonal bipyramidyl structure for C2SnO5.
mined by X-ray diffraction. Selected bond lengths and
angles are given in Table 7, and the molecular structure
with atom numbering of compound II4 is shown in Fig.
1. We found a water of crystallization in the structure
which gives another proof to the possibility of having a
water molecule in the product.
The molecule resides on a general position thus giv-
ing four formula units per unit cell. The molecular

S. Xueqing et al. / Journal of Organometallic Chemistry 566 (1998) 103–110
109
Table 9
Antitumor activity of selected compounds against KB cells, Bel7402 cells and HCT-8 cellsa
Compound
10 (mg ml−1
)
IC50 (mg ml−1
)
KB cells
Bel7402 cells
HCT-8 cells
KB cells
Bel7402 cells
HCT-8 cells
I1
I2
I4
I5
I6
I7
I8
I9
I11
II1
II2
II3
II4
96.2902
96.991.9
96.090.3
99.291.3
95.690.3
96.990.5
92.590.4
94.490.9
95.790.2
93.490.4
89.990.3
89.190.3
75.592.1
96.290.2
92.990.5
92.790.9
91.991.2
92.890.9
96.990.5
96.191.8
92.790.8
93.790.3
89.890.5
89.190.4
87.191.7
77.792.9
93.7912
91.990.7
91.2
5.5
5.4
5.5
5.2
5.5
5.4
5.7
—
5.5
5.6
5.9
5.9
6.9
5.5
5.6
5.7
5.7
5.6
5.4
5.5
3.6
5.5
5.9
5.9
6.0
6.6
5.6
4.7
5.3
5.7
5.5
4.7
5.7
5.1
5.7
5.9
5.9
6.0
8.1
95.690.3
94.991.0
92.590.4
92.892.5
93.191.2
92.591.2
89.591.8
87.692.1
63.494.4
89.991.7
a All compounds have ‘++’, while ‘+++’ stands for good activity.
structure consists of a monomer with a seven-coordi-
nated tin atom surrounded by five oxygens and two
butyl groups. The coordination geometry of tin can be
described as a pentagonal bipyramid with the plane
being defined by four O atoms from two asymmetri-
cally chelating carboxylate groups (Sn(1)–O(5), Sn(1)–
The angles lie in the range 79.5–84.4° for O(5)–Sn(1)–
O(5a) (81.1°), 165.3–172° for O(4)–Sn(1)–O(4a)
(169.0°), 54.0–55.7 for O(4)–Sn(1)–O(5) and 130.6–
147.2° for C(21)–Sn(1)–C(21a) (141.2°).
There is only one example in the literature that
reported the crystal structure of trans-C2SnO5 pen-
taganol bipyramidal which can be compared with the
present one, namely dibutylbis(phenylaceto)tin(IV) hy-
drate Bu2Sn(O2CCH2Ph)2.H2O [17](Fig. 2). Apart from
their similarities, the two complexes exhibit some differ-
ences that warrant a brief mention. The short Sn–O
˚
O(5a)=2.099 A and Sn(1)–O(4), Sn(1)–O(4)=2.158
˚
A) and one O atom from the water molecule, while two
butyl groups occupying the axial position, with the
C–Sn–C angle 141.2°. The pentagon is not regular,
three of the five sides, namely that involving
O(5)O(5a),O(4)O(6),O(4a)O(6), are remarkably longer
than the other two. Consistent with this, the angle
subtended at tin by O(5)O(5a),O(4)O(6) and O(4a)O(6)
are enlarged to 81.1(3)° 84.5(2)° and 84.5(2)°, respec-
tively, while the other two equatorial angles signifi-
cantly reduced to 55.0(3)° from that in an idealized
pentagonal bipyramid (72°). The largest deviation from
the plane of best fit through the five equatorial atoms is
˚
distance of the carboxylate group is 0.135 A shorter
˚
than that in Bu2Sn(O2CCH2Ph)2.H2O (Sn–O, 2.234 A),
˚
while the long Sn–O distance is 0.079 A longer than
˚
that in Bu2Sn(O2CCH2Ph)2.H2O (Sn–O, 2.439 A). The
˚
Sn–Owater distance of 2.54(1) A is significantly longer
than that in Bu2Sn(O2CCH2Ph)2.H2O (Sn–Owater, 2.432
˚
A). These differences can be attributed to the mutual
repulsions of the two bulky germylpropionate groups in
the molecule.
˚
0.0368 A for O(5) and O(5a), with the tin atom lying
exactly on it, while the atom C(21) and C(21a) are away
˚
from the plane (91.9783 A). In the crystal structure,
3.6. In 6itro tests
two C–O bonds of the carboxylate group have been
delocalized, when the two O atoms coordinate to the Sn
A
total of 13 of the nBu2Sn(O2CCHR1CHR2
˚
˚
atom (C(8)–O(4)=1.24(1) A, C(8)–O(5)=1.27(1) A).
The structure of the title compound is structurally
different from those [RnSn(O2CR%)4−n) type complexes
in the literature [16], which is described as skew-trape-
zoidal bipyramid. However, there is a good correspon-
dence in their structural parameters: the short Sn–O
GeR3)2.H2O compounds were screened in vitro for their
antitumor activity against KB cells, HCT-8 cells and
Bel7402 cells. The examination of the results summa-
rized in Table 9 suggests the following conclusions:
1. All compounds tested in general show some activity.
2. The Germatrane-substituted derivatives show a
higher activity than the GePh3-substituted
derivatives.
˚
distances lie in the range of 2.077–2.156 A (Sn(1)–
˚
O(5), Sn(1)–O(5a)=2.099 A), the long Sn–O ones in
˚
the range 2.510–2.711 A (Sn(1)–O(4), Sn(1)–O(4a)=
All compounds are poorly soluble in water. This may
be the main reason for their moderate activity.
˚
˚
2.518 A; Sn(1)–O(6)=2.54 A are also in this range).

110
S. Xueqing et al. / Journal of Organometallic Chemistry 566 (1998) 103–110
Berlin, 1990, p. 201.
[6] (a) E. Lukevics, Appl. Organomet. Chem. 6 (1992) 113. (b) M.Z.
Acknowledgements
Bai, L.F. Geng, L.J. Sun, Hua Xue Tong Bao 11 (1987) 23.
[7] (a) R. Sato, Jpn. Kokai Tokyo koho 56 (1981) 218. (b) J.V.
Scibelli, M.D. Curtis, Synth. React. Inorg. Met.-Org. Chem. 8
(1978) 399.
[8] Y. Kawasaki, T. Tanaka, T.R Okawara, Spect. Acta 105 (1985)
171.
We thank Professor Wang Honggeng and Professor
Yao Xinkan for support of the crystallographic study.
The National Science Foundation of China is also
thanked for support of this research.
[9] G. Singh, V.D. Gupta, Natl. Acad. Sci. Lett. India 5 (1982) 423.
[10] F. Huber, H. Preut, E. Hoffmann, M. Gielen, Acta Cryst. C45
(1989) 51.
References
[11] B. Kushlefsky, I. Simmons, A. Ross, Inorg. Chem. 2 (1963) 187.
[12] M. Gielen, M. Melotte, G. Atassi, R. Willem, Tetrahedron 45
(1989) 1219.
[13] R.J. Rao, R. Soneja, L.V. Shastry, S. Sharma, Synth. React.
Inorg. Met Org. Chem. 24 (1994) 995.
[14] S.J. Blunden, et al., J. Organomet. Chem 226 (1982) 157.
[15] C. Carini, G. Pellizi, P. Tarasconi, et al., J. Chem. Soc. Dalton
Trans. 289 (1989).
[16] E.R.T. Tiekink, Appl. Organomet. Chem. 5 (1994) 1.
[17] S.W. Ng, W. Chen, A. Zainudin, V.G.K Das, W.H. Yip, R.J.
Wang, T.C.W. Mak, J. Cryst. Spectr. Res. 21 (1991) 39.
[1] A.G. Davies, P.J. Smith, in: G. Wilkinson, F.G.A. Stone, E.W.
Abel (Eds.), Comprehensive Organometallic Chemistry, vol. 2,
Pergamon Press, Oxford, 1982.
[2] C.J. Evans, S. Karpel, Organotin Compounds in Modern Tech-
nology, J. Organomet. Chem. Library, vol. 16, Elsevier, Amster-
dam, 1985.
[3] S.J. Blunden, P.A. Cussack, R. Hill, The Industrial Use of Tin
Chemicals, Royal Society of Chemistry, London, 1985.
[4] I. Omae, Organotin Chemistry, J. Organomet. Chem. Library,
vol. 21, Elsevier, Amsterdam, 1989.
[5] V.L. Narayanan, Tin-based Antitumor Drugs, Springer-Verlag,
.