Syntheses and crystal structures of di- and triorganotin(IV) derivatives with 2,4,5-trifluoro-3-methoxybenzoic acid

Article abstract of DOI:10.1016/j.poly.2006.06.022

Eight new organotin(IV) complexes with 2,4,5-trifluoro-3-methoxybenzoic acid R_nSn(O₂CC₆HF₃OCH₃)_4-n (n = 3: R = Ph (1), PhCH₂ (2), Me (3), n-Bu (4); n = 2: R = Ph (5), PhCH₂ (6), Me (7), n-Bu (8)) have been synthesized. All complexes were characterized by elemental, IR, ¹H and ¹³C NMR spectra analyses, and the structures of complexes 1, 3, 7 and 8 were also determined by X-ray crystallography. The geometries at the tin atoms of 1 and 3 are five-coordinated and those of complexes 7 and 8 are six-coordinated. The structures of complexes 1, 3, 7 and 8 have been found to consist of 1D chains built up by intermolecular C-H?F weak hydrogen bonding. Intermolecular C-F?F weak non-hydrogen interactions in the crystal lattice of 3 link the molecules into a 2D network.

Full text of DOI:10.1016/j.poly.2006.06.022

Polyhedron 25 (2006) 3405–3412
www.elsevier.com/locate/poly
Syntheses and crystal structures of di- and triorganotin(IV)
derivatives with 2,4,5-trifluoro-3-methoxybenzoic acid
a,b,
a
a
Chun-Lin Ma
*, Ya-Wen Han , Ru-Fen Zhang
a
Department of Chemistry, Liaocheng University, Liaocheng 252059, PR China
b
Taishan University, Taian 271021, PR China
Received 24 April 2006; accepted 12 June 2006
Available online 4 July 2006
Abstract
Eight new organotin(IV) complexes with 2,4,5-trifluoro-3-methoxybenzoic acid RnSn(O2CC6HF3OCH3)4ꢀn (n = 3: R = Ph (1),
PhCH2 (2), Me (3), n-Bu (4); n = 2: R = Ph (5), PhCH2 (6), Me (7), n-Bu (8)) have been synthesized. All complexes were characterized
by elemental, IR, 1H and 13C NMR spectra analyses, and the structures of complexes 1, 3, 7 and 8 were also determined by X-ray crys-
tallography. The geometries at the tin atoms of 1 and 3 are five-coordinated and those of complexes 7 and 8 are six-coordinated. The
structures of complexes 1, 3, 7 and 8 have been found to consist of 1D chains built up by intermolecular C–Hꢁ ꢁ ꢁF weak hydrogen bond-
ing. Intermolecular C–Fꢁ ꢁ ꢁF weak non-hydrogen interactions in the crystal lattice of 3 link the molecules into a 2D network.
ꢀ 2006 Elsevier Ltd. All rights reserved.
Keywords: 2,4,5-Trifluoro-3-methoxybenzoic acid; Organotin(IV); Weak hydrogen bonding
1. Introduction
organic molecules in general causes drastic changes of the
physico-chemical properties, chemical reactivity and bio-
logical activity in comparison to their non-fluorinated par-
ent complexes [5–7]. Moreover, it was discussed that a C–F
bond can function in certain cases as a weak hydrogen
bond acceptor [8]. Though these interactions are much
weaker than C@Oꢁ ꢁ ꢁH–X (X = O, N) interactions they
do influence molecular packing in crystals [9].
In view of the above reasons and in connection with our
interest in coordination chemistry of organotin(IV) com-
plexes with different carboxylic acids [10], we choose the
fluoro-substituted carboxylate ligand: 2,4,5-trifluoro-3-
methoxybenzoic acid. To our knowledge, although multi-
fluorine substituted organotin(IV) carboxylate derivatives
have been studied before [11], no organotin(IV) derivatives
of 2,4,5-trifluoro-3-methoxybenzoic acid have been reported.
The above considerations stirred our interest in some
detailed syntheses and structures for di- and triorgano-
tin(IV) derivatives of the ligand. Eight complexes
[RnSn(O2CC6HF3OCH3)4ꢀn (n = 3: R = Ph (1), PhCH2
(2); Me (3); n-Bu (4); n = 2: R = Ph (5); PhCH2 (6); Me
The chemistry of organotin(IV) derivatives is a subject
of study with growing interest [1], not only because of
the environmental consequences of the widespread use of
these complexes [2], but also due to the increasing impor-
tance of their medical assays for bactericide and antitumor
purposes [3]. Among the organotin derivatives organo-
tin(IV) carboxylates have had increasing interest shown
due to their activity against various types of cancer. In fact
many dialkyltin(IV) and trialkyltin (IV) complexes display
interesting antitumor activities. Recent work also reveals
higher antitumor activities for various di- and tri-organotin
fluoro-substituted carboxylates than their non-fluorinated
analogues [4]. Furthermore, in the literature people have
reported that the introduction of fluorine atoms into
*
Corresponding author. Address: Department of Chemistry, Liaocheng
University, Liaocheng 252059, PR China. Tel.: +86 635 8238121; fax: +86
538 6715521.
E-mail address: macl@lctu.edu.cn (C.-L. Ma).
0277-5387/$ - see front matter ꢀ 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2006.06.022

3406
C.-L. Ma et al. / Polyhedron 25 (2006) 3405–3412
(7); n-Bu (8))] were obtained by reaction of di- and trialkyltin
tal was formed. Yield: 77%; m.p. 123–125 ꢁC. Anal. Calc.
for C29H25F3O3Sn: C, 58.32; H, 4.22. Found: C, 58.72;
H, 4.31%. IR (KBr, cmꢀ1): mas(C@O), 1590 ms(C–O) 1381,
mas(Sn–C) 560, ms(Sn–C) 518, m(Sn–O) 479. 1H NMR
(CDCl3, ppm): d 7.31–7.81 (m, 1H, C6HF3OCH3), 7.23–
7.52 (m, 15H, Sn–CH2C6H5), 3.16 (s, 6H, Sn–CH2C6H5),
4.03 (s, 3H, OCH3). 13C NMR (CDCl3, ppm): d 32.5
(ArCH2), 112.85, 112.92, 129.76, 128.88, 129.15, 129.37,
130.29, 130.35, 136.74, 136.90, 137.20, 137.32 (Ar–C),
168.25(COO), 62.35 (OCH3).
with 2,4,5-trifluoro-3-methoxybenzoic acid. All the com-
1
plexes were characterized by elemental, IR, H and 13C
NMR spectra analyses. Among them, complexes 1, 3, 7
and 8 are also characterized by X-ray crystallography
diffraction analyses.
2. Experimental
2.1. Materials and measurements
Triphenyltin chloride, trimethyltin chloride, tri-n-butyl-
tin chloride, dimethyltin dichloride, di-n-butyltin dichloride,
diphenyltin dichloride and 2,4,5-trifluoro-3-methoxyben-
zoic acid were commercially available, and they were used
without further purification. Dibenzyltin dichloride and
tribenzyltin chloride were prepared by a standard method
reported in the literature [12]. The melting points were
obtained on a Kofler micro melting point apparatus and
are uncorrected. Infrared-spectra were recorded on a
Nicolet-460 spectrophotometer using KBr discs and sodium
chloride optics. 1H and 13C NMR spectra were obtained on
a Varian Mercury Plus 400 MHz NMR spectrometer. The
chemical shifts are reported in ppm with respect to the refer-
ences and are stated relative to external tetramethylsilane
(TMS) for 1H and 13C NMR. Elemental analyses were
performed with a PE-2400 II elemental apparatus.
2.2.3. [Me3SnO2CC6HF3OCH3] (3)
The procedure is similar to that of complex 1. 2,4,5-Tri-
fluoro-3-methoxybenzoic acid (0.206 g, 1.0 mmol), sodium
ethoxide (0.068 g, 1.0 mmol) and trimethyltin chloride
(0.199 g, 1.0 mmol) were reacted for 12 h at 40 ꢁC. Recrys-
tallized from ether–petroleum, a transparent colorless crys-
tal was formed. Yield: 87%; m.p. 104–106 ꢁC. Anal. Calc.
for C11H13F3O3Sn: C, 35.81; H, 3.55. Found: C, 35.80;
H, 3.73. IR (KBr, cmꢀ1): mas(C@O) 1589, ms(C–O) 1372,
mas(Sn–C) 555, ms(Sn–C) 530, m(Sn–O) 488. 1H NMR
(CDCl3, ppm): d 7.25–7.80 (m, 1H, C6HF3OCH3), 0.60–
0.87 (m, 9H), 4.03 (s, 3H, OCH3) ppm. 13C NMR (CDCl3,
ppm): d 167.46 (COO), 114.87, 138.75, 145.65, 148.02,
148.34, 152.35 (Ar–C), 62.36 (OCH3), 14.27 (–CH3).
2.2.4. [n-Bu3SnO2CC6HF3OCH3] (4)
The procedure is similar to that of complex 1. 2,4,5-Tri-
fluoro-3-methoxybenzoic acid (0.206 g, 1.0 mmol), sodium
ethoxide (0.068 g, 1.0 mmol) and tri-n-butyltin (0.325 g,
1.0 mmol) were reacted for 12 h at 40 ꢁC. Recrystallized
from ether–petroleum, a transparent colorless crystal was
formed. Yield: 78%. m.p. 163–165 ꢁC; Anal. Calc. for
C20H31F3O3Sn: C, 48.51; H, 6.31. Found: C, 48.71; H,
6.18%. IR (KBr, cmꢀ1): mas(C@O) 1586, ms(C–O) 1380,
mas(Sn–C) 561, ms(Sn–C) 527, m(Sn–O) 482. 1H NMR
(CDCl3, ppm): d 7.26–7.75 (m, 1H, C6HF3OCH3), 0.83–
1.54 (m, 27H, Sn–C4H9), 4.04 (s, 3H, OCH3). 13C NMR
(CDCl3, ppm): d 167.46 (COO), 113.00, 138.68, 145.46,
145.85, 147.91, 148.02, 153.67 (Ar–C), 62.36 (OCH3),
22.83, 31.773, 45.57 (–CH2–), 14.27 (CH3).
2.2. Syntheses of the complex 1–8
2.2.1. [Ph3SnO2CC6HF3OCH3] (1)
Under a dry nitrogen atmosphere, 2,4,5-trifluoro-3-
methoxybenzoic acid (0.206 g, 1.0 mmol) and sodium eth-
oxide (0.068 g, 1.0 mmol) were added in benzene (20 ml)
to a Schlenk flask and stirred for about 10 min, then triphe-
nyltin chloride (0.385 g, 1.0 mmol) was added to the mix-
ture. The stirring was continued for 12 h at 40 ꢁC and
then the solution was filtered. The filtrate was gradually
evaporated until a solid product was obtained. The solid
was recrystallized from ether–petroleum and a transparent
colorless crystal of complex 1 was formed. Yield: 88%; m.p.
109–110. ꢁC. Anal. Calc. for C26H19F3O3Sn: C, 56.25; H,
3.45. Found: C, 56.49; H, 3.34%. IR (KBr, cmꢀ1):
mas(C@O) 1582, ms(C–O)1380, mas(Sn–C) 564, ms(Sn–C)
2.2.5. [Ph2Sn(O2CC6HF3OCH3)2] (5)
The procedure is similar to that of complex 1. 2,4,5-Tri-
fluoro-3-methoxybenzoic acid (0.412 g, 2.0 mmol), sodium
ethoxide (0.136 g, 2.0 mmol) and dimethyltin dichloride
(0.219 g, 1.0 mmol) were reacted for 12 h at 40 ꢁC. Recrys-
tallized from ether–petroleum, a transparent colorless crys-
tal was formed. Yield: 83%; m.p. 187–189 ꢁC. Anal. Calc.
for C28H18F6O6Sn: C, 49.23; H, 2.66. Found: C, 49.31;
H, 2.86%. IR (KBr, cmꢀ1): mas(C@O) 1586, ms(C–O) 1378,
mas(Sn–C) 559, ms(Sn–C) 525, m(Sn–O) 488. 1H NMR
(CDCl3, ppm): d 7.15–7.72 (m, 12H, Sn–C6H5 and
C6HF3OCH3), 4.04 (s, 3H, OCH3). 13C NMR (CDCl3,
ppm): d168.65 (COO), 112.42, 112.51, 129.56, 128.78,
129.35, 129.47, 130.49, 130.45, 136.64, 136.77, 137.40,
137.68 (Ar–C), 62.36 (OCH3).
1
523, m(Sn–O) 484. H NMR (CDCl3, ppm): d 7.26–7.52
(m, 1H, C6HF3OCH3), 7.49–7.80 (m, 15H, Sn–C6H5),
4.02 (s, 3H, OCH3). 13C NMR (CDCl3, ppm): d 168.24
(COO), 113.45, 129.00, 129.32, 129.64, 129.62, 130.61,
130.68, 130.75, 136.92, 137.16, 137.40, 137.80 (Ar–C),
62.36 (OCH3).
2.2.2. [(PhCH2)3SnO2CC6HF3OCH3] (2)
The procedure is similar to that of complex 1. 2,4,5-Tri-
fluoro-3-methoxybenzoic acid (0.206 g, 1.0 mmol), sodium
ethoxide (0.068 g, 1.0 mmol) and tribenzyltin chloride
(0.427 g, 1.0 mmol) were reacted for 12 h at 40 ꢁC. Recrys-
tallized from ether–petroleum, a transparent colorless crys-

C.-L. Ma et al. / Polyhedron 25 (2006) 3405–3412
3407
2.2.6. [(PhCH2)2Sn(O2CC6HF3OCH3)2] (6)
2.2.8. [n-Bu2Sn(O2CC6HF3OCH3)2] (8)
The procedure is similar to that of complex 1. 2,4,5-Tri-
fluoro-3-methoxybenzoic acid (0.412 g, 2.0 mmol), sodium
ethoxide (0.136 g, 2.0 mmol) and dibenzyltin dichloride
(0.371 g, 1.0 mmol) were reacted for 12 h at 40 ꢁC. Recrys-
tallized from ether–petroleum, a transparent colorless crys-
tal was formed. Yield: 85%; m.p. 192–194 ꢁC. Anal. Calc.
for C30H22F6O6Sn: C, 50.66; H, 3.12. Found: C, 50.45;
H, 3.24%. IR (KBr, cmꢀ1): mas(C@O) 1589, ms(C–O) 1381,
mas(Sn–C) 588, ms(Sn–C) 533, m(Sn–O) 460. 1H NMR
(CDCl3, ppm): d 7.84–7.36 (m, 12H, C6HF3OCH3 and
Sn–CH2C6H5), 3.29 (s, 4H, Sn–CH2C6H5), 4.06 (s, 3H,
OCH3). 13C NMR (CDCl3, ppm): d 168.05 (COO),
112.65, 112.32, 129.46, 128.58, 129.05, 129.17, 130.19,
130.15, 136.54, 136.70, 137.10, 137.22 (Ar–C), 32.6
(ArCH2), 62.52 (OCH3).
The procedure is similar to that of complex 1. 2,4,5-Tri-
fluoro-3-methoxybenzoic acid (0.412 g, 2.0 mmol), sodium
ethoxide (0.136 g, 2.0 mmol) and di-n-butyltin dichloride
(0.303 g, 1.0 mmol) were reacted for 12 h at 40 ꢁC. Recrys-
tallized from ether–petroleum, a transparent colorless crys-
tal was formed. Yield: 80%; m.p. 117–119 ꢁC. Anal. Calc.
for C24H26F6O6Sn: C, 44.82; H, 4.07. Found: C, 45.0; H,
4.10%. IR (KBr, cmꢀ1): mas(C@O) 1579, ms(C–O)1373,
mas(Sn–C) 586, ms(Sn–C) 537, m(Sn–O) 462. 1H NMR
(CDCl, ppm): d 7.27–7.62 (m, 2H, Sn–C6HF3OCH3),
0.88–1.81 (m, 12H, Sn–C4H9), 4.06 (s, 3H, OCH3). 13C
NMR (CDCl3, ppm): d 170.10 (COO), 113.19, 145.62,
146.87, 148.08, 149.33, 151.63 (Ar–C), 62.50 (OCH3),
22.83, 31.75, 45.36 (–CH2–), 14.28 (CH3).
3. Results and discussion
3.1. Syntheses
2.2.7. [Me2Sn(O2CC6HF3OCH3)2] (7)
The procedure is similar to that of complex 1. 2,4,5-
Trifluoro-3-methoxybenzoic acid (0.412 g, 2.0 mmol),
sodium ethoxide (0.136 g, 2.0 mmol) and dibenzyltin
dichloride (0.371 g, 1.0 mmol) were reacted for 12 h at
40 ꢁC. Recrystallized from ether–petroleum, a transparent
colorless crystal was formed. Yield: 85%; m.p. 192–
194 ꢁC. Anal. Calc. for C18H14F6O6Sn: C, 38.67; H,
2.52. Found: C, 38.65; H, 2.33%. IR (KBr, cmꢀ1):
mas(C@O) 1587, ms(C–O)1379, mas(Sn–C) 586, ms(Sn–C)
The syntheses procedure is given in Scheme 1.
3.2. IR spectra
Comparing the IR spectra of the free ligand with com-
plexes 1–8, the explicit feature is the absence of a band in
the region 3200–3500 cmꢀ1, which appears in the free ligand
as the –OH stretching vibration, thus indicating metal-
ligand bond formation through this site. The absorption
in the region 460–488 cmꢀ1, which is absent in the spectrum
of the free ligand, is assigned to the Sn–O stretching mode.
All these values are consistent with those detected in a
1
532, m(Sn–O) 461. H NMR (CDCl3, ppm): d 7.26–7.60
(m, 2H, C6HF3OCH3), 4.06 (s, 3H, OCH3), 0.85–1.28
(m, 6H, Sn–CH3). 13C NMR (CDCl3, ppm): d 170.80
(COO), 113.29, 145.72, 147.10, 148.18, 149.53, 151.83
(Ar–C), 62.49 (OCH3), 8.87 (–CH3).
F
R
O
R=Ph 1
R= PhCH22
Sn
F
C
F
R
O
R
H3CO
F
F
E tONa
R SnCl
COOH
+
F
3
F
H3CO
H3CO
F
F
R=Me 3
R=n-Bu 4
R
R
R
R
C
O
O
O
Sn
O
Sn
O
O
n
C
F
C
R
R
R
R
F
F
H3CO
F
H3CO
F
F
F
OCH3
F
F
R=Ph 5
R=PhCH26
R=Me 7
R
O
O
EtONa
C
F
F
C
F
2
COOH R SnCl
+
2 2
Sn
R
O
O
R=n-Bu 8
F
H3CO
F
H3CO
F
Scheme 1.

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C.-L. Ma et al. / Polyhedron 25 (2006) 3405–3412
Table 1
number of organotin-oxygen derivatives [13,14]. In the
organotin carboxylate complexes, IR spectroscopy can
provide useful information concerning the coordinate for-
mation of the carboxylate [15]. Dm(mas(COO)–ms(COO)),
202–217 cmꢀ1, are smaller than that of the free ligand,
341 cmꢀ1, but near to that in the sodium salt of the ligand,
200 cmꢀ1, which suggest the presence of bidentate chelating
carboxylate groups [16]. This information is consistent with
the analysis of related X-ray crystallography data.
˚
Selected bond lengths (A) and angles (ꢁ) for 1
Bond lengths
Sn(1)–C(9)
Sn(1)–C(15)
Sn(1)–C(21)
2.130(4)
2.123(5)
2.133(5)
Sn(1)–O(1)
Sn(1)–O(2)
2.076(3)
2.743(4)
Bond angles
O(1)–Sn(1)–C(15)
O(1)–Sn(1)–C(9)
O(1)–Sn(1)–C(21)
O(1)–Sn(1)–O(2)
108.19(16)
97.24(16)
112.47(15)
52.18 (12)
C(15)–Sn(1)–C(9)
C(15)–Sn(1)–C(21)
C(9)–Sn(1)–C(21)
C(9)–Sn(1)–O(2)
112.57(19)
116.14(19)
108.69(18)
149.13(15)
3.3. NMR spectra
1
The H NMR spectra show that the signal for the OH
a weak coordinative interaction with tin along one of the
tetrahedral faces, the structure distortion for the tin atom
in complex 1 is best described as a capped tetrahedron.
As shown in Fig. 2, a pair of intermolecular C–Hꢁ ꢁ ꢁF
hydrogen bonds are recognized, which associate the dis-
crete molecule into a dimer. The C–Hꢁ ꢁ ꢁF distance is
proton (10.89 ppm) in the spectrum of the ligand is absent
in the spectra of the complexes, thus indicating the removal
of the OH proton and the formation of Sn–O bonds. This
is consistent with the IR data. Signals for the other groups
appear in the same positions as in the ligand.
The 13C NMR spectra of all the complexes shown a sig-
nificant downfield shift of all carbon resonances compared
with the free ligand. The shift is a consequence of electron
density transfer from the ligand to the acceptor.
˚
2.557 A, which is shorter than the sum of van der waals
˚
radii of H and F (2.67 A) [18]. The Cꢁ ꢁ ꢁF distance and
˚
the C–Hꢁ ꢁ ꢁF angle are 3.343 A and 142.5ꢁ, respectively.
The dimers of complex 1 are further linked by intermo-
lecular C–Hꢁ ꢁ ꢁF hydrogen bonds. As shown in Fig. 3, the
C(13A) atom acts as a hydrogen-bond donor via the
3.4. X-ray crystallographic studies
3.4.1. Crystal structure of [Ph3SnO2CC6HF3OCH3] (1)
The molecular structure of complex 1 is shown in Fig. 1
and selected bond lengths and angles are given in Table 1.
As can be seen from Fig. 1, the complex possesses a mono-
˚
meric structure, the Sn(1)–O(1) [2.076(3) A] bond length
lies in the range that has been reported as the Sn–O cova-
˚
lent bond length [2.054(3)–2.083(2) A for Sn(1)–O(1)] [17a],
which proves that the oxygen atoms are coordinated to the
tin atoms by a strong chemical bond. The intramolecular
˚
distance [Sn(1)ꢁ ꢁ ꢁO(2)] is 2.743(4) A. Although the distance
is considerably longer than the normal Sn–O covalent bond
length, they lie in the range of Snꢁ ꢁ ꢁO distances of (2.61–
˚
3.02 A), which have been confidently reported for intramo-
lecular bonds [17b,17c]. As the oxygen atom is involved in
Fig. 2. Dimer structure of complex 1.
Fig. 3. 1D chain structure of complex 1, propagation by weak C–Hꢁ ꢁ ꢁF
Fig. 1. Molecular structure of complex 1.
interactions.

C.-L. Ma et al. / Polyhedron 25 (2006) 3405–3412
3409
˚
H(13A) atom to the fluorine F(3AA) atom, and the C(13B)
atom acts the same as C(13A), so the dimers form a 1D
chain with a head-to-tail arrangement. The Cꢁ ꢁ ꢁF and
[2.668(3) A] is longer than other reported complexes [21],
but is far shorter than the sum of the van der Waals radii
˚
of Sn and O (3.68 A) [18]. All these information indicate
that Sn(1)–O(2) is a weak coordinate bond. The Sn-C dis-
tances [2.103(4)–2.114(4) A] are consistent with those
˚
Hꢁ ꢁ ꢁF distances and the C–Hꢁ ꢁ ꢁF angle are 3.239 A,
˚
˚
2.556 A and 130.62ꢁ, respectively. The observed C–Hꢁ ꢁ ꢁF
distances are consistent with phenyl C–Hꢁ ꢁ ꢁF interactions
reported in other triorganotin(IV) carboxylates [17d,20a].
The intermolecular C@O ! Sn coordination in 3 leads
to infinite zigzag chains containing the tin centers and car-
boxyl groups [Fig. 5], which is consistent with another
organotin(IV) complex that has been reported [20a]. Fur-
thermore, the F(2) atom of the ligand in one chain and
the F(2E) atom in another chain form an intermolecular
non-bonding Fꢁ ꢁ ꢁF interaction [Fig. 6], which is similar
to that of the Clꢁ ꢁ ꢁCl interaction reported in the literature
reported for various fluorobenzene complexes (2.36–
˚
2.86 A) [19].
3.4.2. Crystal structure of [Me3SnO2CC6HF3OCH3] (3)
The molecular structure of complex 3 is shown in Fig. 4
and selected bond lengths and angles are given in Table 2.
As can be seen from Fig. 4, the geometry of the tin center
is a distorted trigonal bipyramid and the structure adopted
in the solid state is trans-R3SnO2. The central tin atom is
five-coordinated with the two O atoms [O(1) and O(2A)]
occupying the axial sites, the angle of the axial ligands
[O(1)–Sn(1)–O(2A)] is 174.93(9)ꢁ. Three methyl groups
define the equatorial plane and the sum of the trigonal C–
Sn–C angles is 356.7ꢁ. The carboxylate ligand bridges two
symmetry-related Sn atoms and gives rise to the unequal
Sn–O bond distances. This inequality is reflected in the
C(1)–O bond distance, and the longer C(1)–O(1)
˚
[21]. The Fꢁ ꢁ ꢁF distance (2.820 A) is a little longer than that
˚
has been reported (2.80 A) [22], but is considerably shorter
than the sum of the van der waals radii of two fluorine
˚
atoms (2.94 A)[18]. The C(5)ꢁ ꢁ ꢁF(2A) distance and C(5)–
˚
F(2)ꢁ ꢁ ꢁF(2A) angle is 3.399 A and 103.98ꢁ respectively.
These 1D chains are further linked by intermolecular C–
Hꢁ ꢁ ꢁF hydrogen bonds, as shown in Fig. 7, the C(9) and
C(9B) atoms act as a hydrogen-bond donors via H(9C)
and H(9CB) atoms to phenyl F(2C) and F(2BA) atoms
[Fig. 7] The Cꢁ ꢁ ꢁF, Fꢁ ꢁ ꢁH distance and the C–Hꢁ ꢁ ꢁF angle
˚
˚
[1.282(4) A] is associated with the shorter Sn(1)–O(1)
˚
˚
[2.120(3) A] bond, which is shorter than other reported
are 3.522 A, 2.631 A and 148.2ꢁ respectively. The Fꢁ ꢁ ꢁH
˚
trimethylorganotin(IV) polymeric structures [2.14(1)–
distance (2.631 A) and the C–Hꢁ ꢁ ꢁF angle are bigger than
˚
2.208(2) A] [20a,21] and approaches the covalent radii of
the same type of measurements that are found in complex
˚
˚
˚
Sn and O (2.13 A) [18]. The Sn(1)–O(2A) distance
1 (2.557 A and 142.5ꢁ, 2.556 A and 130.62ꢁ), but shorter
˚
than the sum of van der waals radii of H and F (2.67 A)
[18]. These intermolecular Fꢁ ꢁ ꢁF and C–Hꢁ ꢁ ꢁF interactions
Fig. 5. The 1D chain structure of complex 3, propagation via O ! Sn
coordination.
Fig. 4. The molecular structure of complex 3.
Table 2
˚
Selected bond lengths (A) and angles (ꢁ) for 3
Bond lengths
Sn(1)1–C(9)
Sn(1)–C(10)
Sn(1)–C(11)
C(2)–O(2)
2.109(4)
2.114(4)
2.103(4)
1.227(4)
Sn(1)–O(1)
Sn(1)–O(2A)
C(1)–O(1)
2.120(3)
2.668(3)
1.282(4)
Bond angles
C(11)–Sn(1)–C(9)
C(11)–Sn(1)–C(10)
C(9)–Sn(1)–C(10)
O(1)–Sn(1)–O(2A)
C(10)–Sn(1)–O(2A)
O(1)–Sn(1)–O(2A)
118.8(2)
115.4(2)
122.50(19)
174.93(9)
85.71(15)
174.93(9)
C(11)–Sn(1)–O(1)
C(9)–Sn(1)–O(1)
C(10)–Sn(1)–O(1)
C(9)–Sn(1)–O(2A)
C(11)–Sn(1)–O(2A)
91.15(15)
99.16(15)
97.56(15)
82.21(14)
83.94(15)
Fig. 6. The 2D network structure of complex 3.

3410
C.-L. Ma et al. / Polyhedron 25 (2006) 3405–3412
Fig. 10. The molecular structure of complex 8.
Fig. 7. The 2D network structure of complex 3.
Table 3
˚
Selected bond lengths (A) and angles (ꢁ) for 7
lead to an expansion of the supramolecular structure of 3
Bond lengths
and make it form a 2D network.
Sn(1)–C(21)
Sn(1)–C(17)
Sn(1)–O(1)
C(1)–O(1)
C(9)–O(4)
2.090(9)
2.091(8)
2.115(6)
1.262(9)
1.288(10)
Sn(1)–O(4)
Sn(1)–O(5)
Sn(1)–O(2)
C(1)–O(2)
C(9)–O(5)
2.118(5)
2.506(6)
2.656(6)
1.234(10)
1.229(10)
3.4.3. Crystal structures of [Me2Sn(O2CC6HF3OCH3)2]
(7) and [n-Bu2Sn(O2CC6HF3OCH3)2] (8)
The molecular structures of complexes 7 and 8 are
shown in Figs. 8 and 10, and selected bond lengths and
angles are given in Tables 3 and 4. The geometry at the cen-
tral Sn atoms in both complexes of 7 and 8 is a skew-trap-
ezoidal bipyramidal geometry. The four O atoms, which
derive from two chelate carboxylate ligands, define the
basal plane. The C–Sn–C angle [142.4(4)ꢁ for 7, 147.5(2)ꢁ
Bond angles
C(21)–Sn(1)–C(17)
C(21)–Sn(1)–O(1)
C(17)–Sn(1)–O(1)
C(21)–Sn(1)–O(4)
O(1)–Sn(1)–O(5)
C(21)–Sn(1)–O(4)
O(1)–Sn(1)–O(2)
O(5)–Sn(1)–O(2)
142.2(4)
C(17)–Sn(1)–O(4)
O(1)–Sn(1)–O(4)
C(21)–Sn(1)–O(5)
C(17)–Sn(1)–O(5)
O(4)–Sn(1)–O(5)
C(17)–Sn(1)–O(2)
O(4)–Sn(1)–O(2)
103.1(3)
105.2(4)
103.9(3)
105.1(3)
135.8(2)
105.1(3)
53.0(2)
80.3(2)
86.3(3)
89.4(3)
55.6(2)
88.4(3)
133.3(2)
171.17(18)
Table 4
˚
Selected bond lengths (A) and angles (ꢁ) for 8
Bond lengths
Sn(1)–C(21)
Sn(1)–C(17)
Sn(1)–O(1)
C(1)–O(1)
C(9)–O(4)
2.109(5)
2.107(5)
2.128(3)
1.287(6)
1.281(6)
Sn(1)–O(4)
Sn(1)–O(5)
Sn(1)–O(2)
C(1)–O(2)
C(9)–O(5)
2.141(3)
2.531(4)
2.562(3)
1.226(6)
1.245(6)
Fig. 8. The molecular structure of complex 7.
Bond angles
C(17)–Sn(1)–C(21)
C(17)–Sn(1)–O(1)
C(21)–Sn(1)–O(1)
C(21)–Sn(1)–O(4)
O(1)–Sn(1)–O(5)
C(17)–Sn(1)–O(2)
O(1)–Sn(1)–O(2)
O(5)–Sn(1)–O(2)
147.5(2)
99.8(2)
C(17)–Sn(1)–O(4)
O(1)–Sn(1)–O(4)
C(17)–Sn(1)–O(5)
C(21)–Sn(1)–O(5)
O(4)–Sn(1)–O(5)
C(21)–Sn(1)–O(2)
O(4)–Sn(1)–O(2)
102.97(19)
82.60 (13)
88.02(19)
87.41(18)
55.31(12)
89.06(17)
137.08(12)
105.04(17)
100.69(17)
137.80(12)
88.60(19)
54.58(12)
167.61(12)
for 8] lies in the range of C–Sn–C angles of 122.6–156.9ꢁ
found for diorganotin derivatives in which the organo sub-
stituents do not adopt cis- or trans-geometries about the tin
atom [23]. The carboxylate ligands chelate the Sn center
with asymmetric Sn–O bond distances and this asymmetry
is related to the shorter Sn–O bonds. The degree of asym-
metry in the Sn–O bond distances is not equal to the differ-
ence between the Sn–O bond distances for two carboxylate
Fig. 9. The dimer structure of complex 7.

C.-L. Ma et al. / Polyhedron 25 (2006) 3405–3412
3411
˚
˚
˚
˚
˚
˚
ligands (0.541 A and 0.388 A for 7, 0.434 A and 0.390 A for
8). The anisobidente mode of coordination of the carboxyl-
ate is also reflected in the disparity of the associated car-
equal (3.121 A for 7 and 3.097 A for 8), which is less than
˚
the sum of the van der Walls radii of Sn and O (3.68 A) [18]
and between those that have been reported in [Et2S-
˚
Ph2Sn(O2CCH2Cl)2
˚
bon–oxygen bonds. Although the Sn(1)–O(2) (2.656 A for
7 and 2.562(3) A for 8) and Sn(1)–O(5) (2.506 A for 7
and 2.531(4) A for 8) bonds are longer than the sum of
the covalent radii of Sn and O (2.13 A), they are neverthe-
n(O2CC4H3S)]
(2.891 A)
and
˚
˚
˚
(3.552 A) [24,25]. The interaction of Snꢁ ꢁ ꢁF is similar to
˚
the Snꢁ ꢁ ꢁCl interaction that has been reported [26] and
˚
˚
˚
the distance is 3.635 A for 7 and 3.638A for 8.
less significantly below the sum of the van der waals radii
of these atoms (3.68A) [18].
The most interesting aspect of the structure concerns the
intermolecular weak Snꢁ ꢁ ꢁO and Snꢁ ꢁ ꢁF interactions,
which help in the construction of the dimer as shown in
Figs. 9 and 11. The two weak Snꢁ ꢁ ꢁO bond lengths are
Moreover, for complex 7 the dimers are connected into a
1 D chain through C–Hꢁ ꢁ ꢁF hydrogen bonding. The Cꢁ ꢁ ꢁF
˚
˚
and Hꢁ ꢁ ꢁF distances and the C–Hꢁ ꢁ ꢁF angle are 3.312 A,
˚
2.612 A and 130.01ꢁ respectively, these data are consistent
with those found in the literature [19]. For complex 8, we
can find two types of shorter distances that are formed
by the phenyl F and the methyl H. One is a little longer
than the other. For the longer one, its Cꢁ ꢁ ꢁF and Hꢁ ꢁ ꢁF dis-
˚
˚
tances and the C–Hꢁ ꢁ ꢁF angle are 3.511 A, 2.607 A and
157.06ꢁ respectively; and for the shorter one, its Cꢁ ꢁ ꢁF
˚
and Hꢁ ꢁ ꢁF distances and the C–Hꢁ ꢁ ꢁF angle are 3.297 A,
˚
2.517 A and 138.34ꢁ respectively. So a 1D chain structure
in the solid state is propagated by two types of C–Hꢁ ꢁ ꢁF
weak interactions. Further, the C–Hꢁ ꢁ ꢁF distance
˚
(2.517 A) is the shortest among the above mentioned in this
article.
4. X-ray crystallography
Crystals were mounted in Lindemann capillaries under
nitrogen. All X-ray crystallographic data were collected on
a Bruker SMART CCD 1000 diffractometer with graphite
˚
monochromated Mo Ka radiation (k = 0.71073 A) at
Fig. 11. The dimer structure of complex 8.
Table 5
Crystal data collection and structure refinement parameters for 1, 3, 7 and 8
Complex
1
3
7
8
Empirical formula
Formula weight
Crystal system
Space group
Unit cell dimensions
C
555.10
monoclinic
P2 (1)/c
26H19F3O3Sn
C11H13F3O3Sn
368.90
monoclinic
P2 (1)/c
C18H14F6O6Sn
558.98
triclinic
C24H26F6O6Sn
643.14
monoclinic
P2 (1)/c
ꢀ
P1
˚
a (A)
11.805(4)
8.705(3)
22.985(8)
90
98.804(5)
90
10.970(8)
10.132(7)
13.235(9)
90
113.691(9)
90
7.684(4)
9.530(6)
9.3711(15)
19.609(3)
14.772(2)
90
103.894(2)
90
˚
b (A)
˚
c (A)
14.285(8)
84.725(8)
75.599(8)
77.605(5)
2
1.878
1.382
548
a (ꢁ)
b (ꢁ)
c (ꢁ)
Z
4
4
4
Dcalc (Mg mꢀ3
Absorption coefficient (mmꢀ1
F (000)
)
1.580
1.143
1104
1.819
1.929
720
1.621
1.048
1288
)
Crystal size (mm)
h Range for data collection (ꢁ) 1.75–25.00
Index ranges
0.52 · 0.48 · 0.43
0.53 · 0.48 · 0.43
2.62–25.00
ꢀ12 6 h 6 13
ꢀ12 6 k 6 11
ꢀ15 6 l 6 15
6664
0.45 · 0.38 · 0.29
2.19–25.01
ꢀ9 6 h 6 9
ꢀ11 6 k 6 11
ꢀ14 6 l 6 16
5047
0.58 · 0.43 · 0.41
2.08–25.01
ꢀ10 6 h 6 11
ꢀ23 6 k 6 23
ꢀ15 6 l 6 17
13586
ꢀ14 6 h 6 11
ꢀ10 6 k 6 10
ꢀ18 6 l 6 27
11816
Reflections collected
Unique reflections (Rint
)
4111 (0.0459)
4111/0/299
1.000
2361 (0.0327)
2361/0/163
1.006
3382 (0.0304)
3382/0/282
1.001
4644 (0.0367)
4644/290/334
1.006
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I > 2r(I)]
R indices (all data)
R1 = 0.0469, wR2 = 0.1135 R1 = 0.0296, wR2 = 0.0760 R1 = 0.0625, wR2 = 0.1626 R1 = 0.0402, wR2 = 0.1011
R1 = 0.0631, wR2 = 0.1304 R1 = 0.0366, wR2 = 0.0825 R1 = 0.0754, wR2 = 0.1736 R1 = 0.0644, wR2 = 0.1188

3412
C.-L. Ma et al. / Polyhedron 25 (2006) 3405–3412
(c) A.R. Choudhury, N.T. Guru Row, Cryst. Growth Des. 4 (2004)
47;
(d) A. Sun, D.C. Lankin, K. Hardcastle, J.P. Snyder, Chem. Eur. J. 11
(2005) 1579.
298(2) K. A semi-empirical absorption correction was
applied to the data. The structure was solved by direct meth-
ods using SHELXS–97 and refined against F2 by full-matrix
least squares using SHELXL–97. Hydrogen atoms were placed
in calculated positions. Crystal data and experimental details
of the structure determinations are list in Table 5.
[10] (a) C.L. Ma, Y.F. Han, R.F. Zhang, D.Q. Wang, J. Chem. Soc.
Dalton Trans. (2004) 1832;
(b) C.L. Ma, J.F. Sun, J. Chem. Soc. Dalton Trans. (2004) 1785;
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5. Supplementary material
(d) C.L. Ma, Y.F. Han, R.F. Zhang, D.Q. Wang, Eur. J. Inorg.
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(e) C.L. Ma, Q.F. Zhang, R.F. Zhang, D.Q. Wang, Chem. Eur. J. 12
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(f) C.L. Ma, J.K. Li, R.F. Zhang, D.Q. Wang, Inorg. Chim. Acta. 358
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Crystallographic data (excluding structure factors) for
the structure analysis of the compounds have been
deposited with the Cambridge Crystallographic Data
Center, CCDC No. 600461 1, 600462 3, 600459 7,
600460 8. Copies of these information may be obtained
free of charge from The Director, CCDC, 12 Union
Road, Cambridge, CB2 1EZ, UK (fax: +44-1223-
336033; e-mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
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