Assembly of triorganotin chloride with selenite ligands to macrocyclic, zigzag, helical, and linear structures: Syntheses, characterizations, and crystal structures of [R3Sn(O2SeC6H 4-4-Et)] n and [R3Sn(O2SeC 6H4-2-Et)] n (R = Me, C6H 5) complexes

Article abstract of DOI:10.1007/s11224-013-0368-0

Four new triorganotin(IV) complexes, [R₃Sn(O₂SeC ₆H₄-4-Et)]₄ (R = Me 1), [R₃Sn(O ₂SeC₆H₄-4-Et)] _n (R = Ph 2), [R ₃Sn(O₂SeC₆H₄-2-Et)] _n (R = Me 3; Ph 4) have been synthesized by the treatment of 4-ethylbenzeneseleninic acid, 2-ethylbenzeneseleninic acid, and the corresponding triorganotin(IV) chloride with sodium ethoxide in methanol. All of the complexes were characterized by elemental analysis, FT-IR, NMR (¹H, ¹³C, and ¹¹⁹Sn) spectroscopy, TGA, and X-ray crystallography. Crystal structures show that all of the complexes are generated by the bidentate oxygen atoms and the five-coordinated tin centers with trigonal bipyramid geometry. The structural analyses reveal that complex 1 has a centrosymmetric tetranuclear triorganotin selenite with 16-membered macrocycle, which is formed by trimethyltin and ligand alternate linking. A series of C- H···O and π-π stacking interactions in complex 1 play an important function in the supramolecular aggregation. Complex 3 has two 1D spring-like chiral helical chains and crystallizes in the monoclinic space group P2₁, which is chiral. Complex 2 and 4 are both 1D infinite neutral chain polymers and complex 2 forms a 2D supramolecular framework through intermolecular C-H···O interactions.

Full text of DOI:10.1007/s11224-013-0368-0

Struct Chem (2014) 25:949–958
DOI 10.1007/s11224-013-0368-0
ORIGINAL RESEARCH
Assembly of triorganotin chloride with selenite ligands
to macrocyclic, zigzag, helical, and linear structures: syntheses,
characterizations, and crystal structures of [R3Sn(O2SeC6H4-4-
Et)]n and [R3Sn(O2SeC6H4-2-Et)]n (R 5 Me, C6H5) complexes
•
Chunlin Ma Zhenxing Li Qianli Li
•
•
•
Fei Wang Rufen Zhang Qingfu Zhang
•
Received: 5 July 2013 / Accepted: 28 October 2013 / Published online: 13 November 2013
ꢀ Springer Science+Business Media New York 2013
Abstract Four
new
triorganotin(IV)
complexes,
Introduction
[R3Sn(O2SeC6H4-4-Et)]4 (R = Me 1), [R3Sn(O2SeC6H4-4-
Et)]n (R = Ph 2), [R3Sn(O2SeC6H4-2-Et)]n (R = Me 3; Ph
4) have been synthesized by the treatment of 4-ethylben-
zeneseleninic acid, 2-ethylbenzeneseleninic acid, and the
corresponding triorganotin(IV) chloride with sodium eth-
oxide in methanol. All of the complexes were characterized
by elemental analysis, FT-IR, NMR (1H, 13C, and 119Sn)
spectroscopy, TGA, and X-ray crystallography. Crystal
structures show that all of the complexes are generated by
the bidentate oxygen atoms and the five-coordinated tin
centers with trigonal bipyramid geometry. The structural
analyses reveal that complex 1 has a centrosymmetric
tetranuclear triorganotin selenite with 16-membered mac-
rocycle, which is formed by trimethyltin and ligand alter-
nate linking. A series of C–HꢀꢀꢀO and p–p stacking
interactions in complex 1 play an important function in the
supramolecular aggregation. Complex 3 has two 1D
spring-like chiral helical chains and crystallizes in the
monoclinic space group P21, which is chiral. Complex 2
and 4 are both 1D infinite neutral chain polymers and
complex 2 forms a 2D supramolecular framework through
intermolecular C–HꢀꢀꢀO interactions.
Recently, metal-directed self-assembly has become a
powerful tool for the construction of systems containing
cavities or possessing intrinsic physical and chemical
properties that are promising for the creation of new
materials and new metal-based drugs [1–3]. Organotin
compounds are an important branch of organometallic
compounds and are receiving intensive attention for use as
reagents or catalysts in organic synthesis, particularly in the
area of biochemical activity [4, 5]. In the past few years,
many kinds of organic ligands such as carboxylic acids,
sulfonic acids, phosphinic acids, and phosphonic acids
have been selected to produce various organotin deriva-
tives with attractive structures containing ladder, O-cap-
ped, cube, butterfly drum, football cage, and cyclic trimer
[6, 7]. Apart from these interesting molecular structures,
many organotin compounds have been organized into
interesting supramolecular structures by a combination of
non-covalent interactions including O–HꢀꢀꢀO, C–HꢀꢀꢀO, N–
HꢀꢀꢀO, C–Hꢀꢀꢀp, and p–p stacking. In our previous work, we
have reported several organotin molecular/supramolecular
structures derived from carboxylic acids, phosphinic acids,
and phosphonic acids through self-assembly [8–10].
Keywords Areneseleninic acid ꢀ Triorganotin(IV)
complex ꢀ 16-Membered macrocycle ꢀ Chains
Organoseleninic acid, similar to carboxylate/phosphi-
nate group, also has two donor oxygen atoms and one
negative charge [11]. Thus, they and their salts can be
viewed as isosteres of the biologically ubiquitous anionic
O-phosphate, O-sulfate, and carboxylate groups and pre-
dicted to resist the action of most enzymes that operate in
the biosynthesis or subsequent processing of those bioa-
nions. However, organoseleninic acid is significantly dif-
C. Ma (&) ꢀ Z. Li ꢀ Q. Li ꢀ F. Wang ꢀ R. Zhang ꢀ Q. Zhang
Department of Chemistry, Liaocheng University,
Liaocheng 252059, People’s Republic of China
e-mail: macl856@163.com
-
ferent from both Ph2PO2 and PhSO3-, containing only a
three-coordinate central atom; and it is also unlike car-
boxylate and nitrate groups in that the Se possesses a
123

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Struct Chem (2014) 25:949–958
Scheme 1 The syntheses
procedures of complexes 1-4
1
stereoactive lone pair. Organotin(IV) selenite may be one
kind of interesting organotin(IV) derivatives, but a much
less clear picture on the structural coordination chemistry
has been developed. Therefore, it was worth to be resear-
ched on the interaction between organotin species and or-
ganoseleninic acid [12, 13]. To continue research in this
area, we selected 4-ethylbenzeneseleninic acid and 2-eth-
ylbenzeneseleninic acid as bridging ligands, and succeeded
in obtaining four triorganotin complexes. Here we report
the syntheses, characterization, and crystal structures of
these new organotin(IV) selenite complexes.
spectrophotometer using KBr disks and NaCl optics. H,
13C, and 119Sn NMR spectra were recorded with a Varian
Mercury Plus 400 spectrometer operating at 400, 100.6,
and 149.2 MHz, respectively. The spectra were acquired at
room temperature (298 K), unless otherwise specified. 13C
NMR spectra are broadband-proton-decoupled. Chemical
shifts cited were references to external tetramethylsilane
for H and 13C NMR and to tetramethyltin (Me4Sn) for
1
119Sn NMR. TGA was carried out with a Perkin-Elmer
Pyris-1 instrument with a heating rate of 10 ꢁC min-1 from
50 to 550 ꢁC and with a 20.0 cm3 min-1 nitrogen gas flow.
Syntheses of the complexes 1–4
Experimental details
The syntheses procedures of complexes 1–4 are given in
Scheme 1.
Materials and measurements
[Me3Sn(O2SeC6H4-4-Et)]4 1 The reaction was carried
out under nitrogen atmosphere. 4-ethylbenzeneseleninic
acid (0.217 g, 1 mmol) was added to the solution of
methanol (30 ml) with sodium ethoxide (0.068 g, 1 mmol),
and the mixture was stirred for 0.5 h. After the addition of
trimethyltin chloride (0.199 g, 1 mmol), the mixture was
stirred at 50 ꢁC for 12 h and then filtered. The solvent was
gradually removed by evaporation under vacuum until a
solid product was obtained. The solid was then
Trimethyltin chloride and triphenyltin chloride are com-
mercially available. They were all used without further
purification. Sub-areneseleninic acids were prepared by the
reported method in the literature [14, 15]. Solvents were
purified by standard procedures and were freshly distilled
prior to use. Melting points were obtained with Kofler
micro-melting point apparatus and were reported uncor-
rected. Infrared spectra were recorded with a Nicolet-5700
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Struct Chem (2014) 25:949–958
951
recrystallized from methanol, and colorless crystals of
Results and discussion
complex
1 were recovered. Yield: 78 %. m.p. =
150–153 ꢁC. Anal. Calc. for C44H72O8Se4Sn4: C, 34.77; H,
4.78 %. Found: C, 34.43; H, 5.01 %. IR (KBr, cm-1):
m(Sn–C) 544, m(Sn–O) 445, m(Se–O) 737. 1H NMR [CD3Cl,
ppm]: d = 7.28–7.57 (m, 16H, 4C6H4), 2.67 (q,
J = 7.6 Hz, 8H, 4CH2), 1.22 (t, J = 7.6 Hz, 12H, 4CH3),
IR spectra
The IR spectra of complexes 1–4 were recorded in the
range of 4,000–400 cm-1. The vibrational frequencies of
interest are those associated with the Sn–O, Se–O, and Sn–
C groups. The bands at 2,720–3,100 cm-1 which appear in
the free ligands as the m(O–H) stretching vibrations, are not
observed in complexes 1–4, thus indicating metal–ligand
bond formation through these sites. The strong absorptions
in the region 445–546 cm-1, which are absent in the
spectra of free ligand, are assigned to the Sn–O stretching
mode of vibration [16]. The strong absorption that appears
at about 737–772 cm-1 in the respective spectra of all the
complexes is assigned to the Se–O stretching mode of
vibration according to the Ref. [17]. A weak band in
531–547 cm-1 for complexes 1–4 is assigned to m(Sn–C),
indicating a non-linear trans-configuration of the C–Sn–C
moitey. All these values are consistent with those detected
in a number of organotin(IV) derivatives [18–20].
2
0.49 (s, 36H, 4Sn–CH3, JSn–H = 66 Hz). 13C NMR
[CD3Cl, ppm]: d = 122.1, 127.4, 131.5, 139.5 (Ar–C),
1
25.8 (CH3CH2), 15.9 (CH3CH2), 2.3 (Sn–CH3, JSn–C
=
523.6 Hz). 119Sn NMR [CD3Cl, ppm]: 92.6.
[Ph3Sn(O2SeC6H4-4-Et)]n 2 The procedure is similar to
that of complex 1, 4-ethylbenzeneseleninic acid (0.217 g,
1 mmol), sodium ethoxide (0.068 g, 1 mmol) and triphen-
yltin chloride (0.385 g, 1 mmol) reacted for 12 h at 50 ꢁC.
Recrystallized from diethyl ether, a transparent colorless
crystal was recovered. Yield: 76 %. m.p. = 232–235 ꢁC.
Anal. Calc. for C26H24O2SeSn: C, 55.16; H, 4.27 %. Found:
C, 54.83; H, 4.54 %. IR (KBr, cm-1): m(Sn–C) 531, m(Sn–O)
454, m(Se–O) 746. 1H NMR [CD3Cl, ppm]: d = 7.09–7.87
(m, 19H, -Ph), 2.64 (q, J = 7.6 Hz, 2H, CH2), 1.18 (t,
J = 7.6 Hz, 3H, CH3), 13C NMR [CD3Cl, ppm]:
d = 121.2–143.4 (Ar–C), 24.7 (CH3CH2), 15.3(CH3CH2).
119Sn NMR [CD3Cl, ppm]: 90.5.
NMR spectra
1
The H NMR spectra show that the signals of the –SeO2H
[Me3Sn(O2SeC6H4-2-Et)]n 3 The procedure is similar to
that of complex 1, 2-ethylbenzeneseleninic acid (0.217 g,
1 mmol), sodium ethoxide (0.068 g, 1 mmol), and tri-
methyltin chloride (0.199 g, 1 mmol) reacted for 12 h at
50 ꢁC. Recrystallized from diethyl ether, a transparent
colorless crystal was recovered. Yield: 82 %.
m.p. = 223–226 ꢁC. Anal. Calc. for C11H18O2SeSn: C,
34.77; H, 4.78 %. Found: C, 35.06; H, 4.38 %. IR (KBr,
cm-1): m(Sn–C) 545, m(Sn–O), 473, m(Se–O) 772. 1H NMR
[CD3Cl, ppm]: d = 7.15–7.39 (m, 4H, -Ph), 2.79 (q,
J = 7.6 Hz, 2H, CH3CH2), 1.17 (t, J = 7.6 Hz, 3H,
proton in the spectrum of the ligands are absent in these
complexes, indicating the removal of the –SeO2H proton
and the formation of Sn–O bond. This fits well with the IR
data. The 13C NMR spectra of all complexes show a sig-
nificant downfield shift of all carbon resonances compared
with the free ligands because of an electron-density transfer
from the ligands to metal atoms [15]. The 119Sn NMR
spectra of complexes show resonances between
d = 86.7–92.6 ppm. As reported in the literature [21], d
values for 119Sn NMR spectra in the -210 to -400, -90 to
-190, and 200 to -60 ppm ranges have been associated
with hexa-, penta-, and tetracoordinated tin centers,
respectively. The X-ray crystallography shows that the Sn
complexes 1–4 are typically pentacoordinated. However,
the 119Sn NMR spectra resonances show only four-coor-
dinated atoms for these complexes. This may be caused by
some of the weak Sn–O bonds rupturing in solution and the
five-coordinated tin atoms become four-coordinated.
2
CH3CH2), 0.42 (s, 9H, Sn–CH3, JSn–H = 68). 13C NMR
[CD3Cl, ppm]: d = 125.0, 127.0, 129.4, 131.5, 143.4,
150.1 (C6H4), 26.4 (CH3CH2), 16.6 (CH3CH2), 2.4 (Sn–
CH3, 1JSn–C = 506.6 Hz). 119Sn NMR [CD3Cl, ppm]: 88.2.
[Ph3Sn(O2SeC6H4-2-Et)]n 4 the procedure is similar to
that of complex 1, 2-methoxybenzeneseleninic acid
(0.217 g, 1 mmol), sodium ethoxide (0.068 g, 1 mmol) and
triphenyltin chloride (0.385 g, 1 mmol) were reacted for
12 h at 50 ꢁC. Recrystallized from diethyl ether, a trans-
parent colorless crystal was recovered. Yield: 73 %.
m.p. = 166–168 ꢁC. Anal. Calc. for C26H24O2SeSn: C,
55.16; H, 4.27 %. Found: C, 54.81; H, 4.52 %. IR (KBr,
cm-1): m(Sn–C), 546, m(Sn–O), 467,m(Se–O) 758. 1H NMR
[CD3Cl, ppm]: d = 7.57–7.69 (m, 19H, -Ph), 2.83 (q,
J = 7.6 Hz, 2H, CH3CH2), 1.20 (t, J = 7.6 Hz, 3H,
CH3CH2). 13C NMR [CD3Cl, ppm]: d = 115.4–162.3
(Ar–C), 25.3 (CH3CH2), 16.1 (CH3CH2). 119Sn NMR
[CD3Cl, ppm]: 86.7.
X-ray crystallography
Single-crystal X-ray diffraction data were collected on a
Bruker SMART-1000 CCD diffractometer with graphite-
˚
monochromated Mo Ka (k = 0.71,073 A) radiation at
room temperature. The structures were solved by direct
methods and refined by the full-matrix least-squares
methods on F2 using the SHELX-97 program. All non-
hydrogen atoms were refined with anisotropic displacement
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Struct Chem (2014) 25:949–958
Table 1 Crystallographic data and structure refinement parameters for complexes 1, 2, 3, and 4
Complex
1
2
3
4
Empirical formula
M
C44H72O8Se4Sn4
1,519.62
Triclinic
C26H24O2SeSn
566.10
C11H18O2SeSn
379.90
C26H24O2SeSn
566.10
Orthorhombic
Pna21
Crystal system
Space group
Monoclinic
P21/c
Monoclinic
P21
P-1
˚
a (A)
7.6,749(6)
12.1328(11)
16.4286(14)
86.355(2)
84.8650(10)
71.7120(10)
1,445.7(2)
1
17.017(8)
10.492(8)
23.204(14)
90
10.4671(11)
10.2180(10)
14.0939(13)
90
12.456(6)
26.562(13)
7.073(4)
90
˚
b (A)
˚
c (A)
a (ꢁ)
b(ꢁ)
c(ꢁ)
95.2710(10)
90
107.2380(10)
90
90
90
3
˚
V (A )
2,361.0(4)
4
1,439.7(2)
4
2,340(2)
4
Z
Dcalc (Mg/m3)
1.745
1.593
1.753
1.607
l (mm-1
)
4.267
2.643
4.285
2.666
F(000)
736
1,120
736
1,120
Crystal size (mm)
0.17 9 0.08 9 0.05
7,075
0.39 9 0.33 9 0.20
11,560
0.40 9 0.12 9 0.08
7,373
0.21 9 0.15 9 0.10
11,417
Reflections collected
Unique reflections
Rint
4,884
4,166
4,810
3,982
0.1050
0.0386
0.0500
0.0601
Goodness-of-fit on F2
R1[I [ 2r(I)],R1 (all data)
wR2[I [ 2r(I)],wR2 (all data)
1.035
1.068
0.995
1.053
0.1487, 0.2419
0.3266, 0.3726
0.0336, 0.0648
0.0639, 0.0798
0.0497, 0.0649
0.1216, 0.1325
0.0505, 0.0645
0.1209, 0.1269
parameters. The hydrogen atoms attached to carbon atoms
were generated geometrically and refined using riding
mode. Crystal data and experimental details of the structure
determinations are listed in Table 1.
Crystal structure of complex 1
The molecular structure of complex 1 is shown in Fig. 1, and
selected bond lengths and angles are listed in Table 2,
respectively. The molecule of complex 1 consists of four
trimethyltin fragments linked together by four bridging sel-
enite groups, forming a 16-membered Sn4Se4O8 tetranuclear
macrocycle. The adjacent trimethyltin motifs are bridged by
the 4-ethylbenzeneseleninic acid ligand via a bidentate
coordination mode creating an approximate molecular
square. Each tin atom is penta-coordinated trigonal bipyra-
midal (C3O2 coordination environment), with the apical
positions being taken up by the oxygen atoms of two dif-
ferent seleninic acid ligands. The equatorial plane is occu-
pied by three methyl groups and the sum of the angles around
tin atom is 359.6(17)ꢁ, indicating that C(9), C(10), C(11),
and Sn(1) are almost in the same plane with the slight
Fig. 1 The molecular structure of complex 1
˚
character, 2.08(3)–2.13(3) A, and the other group corre-
sponding to Sn–O bonds of coordinative character, 2.32(3)–
˚
2.40(3) A. The O–Sn–O angle is almost linear with a value of
176.6ꢁ, close to that reported in [EtPh2SnOC(O)CH3] [22].
The size of cavity in this macrocycle can be evaluated from
the transannular Sn(1)–Sn(1)#1 and Sn(2)–Sn(2)#1 dis-
˚
deviation (mean deviation 0.076 A). Due to the anisobid-
˚
tances, which are 6.859 and 8.880 A, respectively, which
entate coordination mode of the selenite groups to the tin
atoms, two groups of different Sn–O bond lengths were
found, one group corresponding to Sn–O bonds of covalent
is close to our previous reported complex [Ph3Sn
(O-OC5H4NCO2)]6 [9]. Worth mentioning here is that the
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Struct Chem (2014) 25:949–958
953
Table 2 Selected bond lengths
˚
Complex 1
(A) and angles (ꢁ) for complex 1
Sn(1)–C(11)
2.06(3)
2.09(3)
2.16(3)
2.269(19)
2.28(2)
2.12(3)
2.15(3)
2.19(4)
2.28(2)
Sn(2)–O(4)
Se(1)–O(4)
Se(1)–O(3)
Se(1)–C(20)
Se(2)–O(2)
Se(2)–O(1)
Se(2)–C(6)
O(2)–Sn(2)#1
2.279(19)
1.683(19)
1.71(2)
2.04(3)
1.70(2)
1.71(2)
1.95(3)
2.28(2)
Sn(1)–C(9)
Sn(1)–C(10)
Sn(1)–O(1)
Sn(1)–O(3)
Sn(2)–C(12)
Sn(2)–C(14)
Sn(2)–C(13)
Sn(2)–O(2)#1
C(11)–Sn(1)–C(9)
C(11)–Sn(1)–C(10)
C(9)–Sn(1)–C(10)
C(11)–Sn(1)–O(1)
C(9)–Sn(1)–O(1)
C(10)–Sn(1)–O(1)
C(11)–Sn(1)–O(3)
C(9)–Sn(1)–O(3)
C(10)–Sn(1)–O(3)
O(1)–Sn(1)–O(3)
C(12)–Sn(2)–C(14)
C(12)–Sn(2)–C(13)
C(14)–Sn(2)–C(13)
119.9(13)
C(12)–Sn(2)–O(2)#1
C(14)–Sn(2)–O(2)#1
C(13)–Sn(2)–O(2)#1
C(12)–Sn(2)–O(4)
C(14)–Sn(2)–O(4)
C(13)–Sn(2)–O(4)
O(2)#1–Sn(2)–O(4)
O(4)–Se(1)–O(3)
O(4)–Se(1)–C(20)
O(3)-Se(1)–C(20)
O(2)–Se(2)–O(1)
O(2)–Se(2)–C(6)
O(1)–Se(2)–C(6)
92.6(11)
87.8(10)
90.3(11)
90.6(11)
83.6(10)
94.7(11)
171.4(7)
102.6(10)
97.6(12)
98.4(12)
105.3(10)
96.3(11)
102.3(11)
119.1(13)
121.1(13)
91.9(9)
90.9(10)
87.2(9)
89.0(9)
88.5(10)
92.6(9)
179.1(7)
113.3(16)
122.8(15)
123.9(15)
Symmetry codes for complex 1:
#1-x ? 1, -y ? 2, -z ? 2
Fig. 2 The 1D polymeric chain
structure of complex 1 made up
of intermolecular weak
C–H…O interactions
dimensions of the cavities in this complex are large enough to
capture some guest molecules, suggesting it is a potentially
macrocylic host to include guest molecules.
showing the presence of significant offset p–p stacking
interactions, which are closely in agreement with what have
been reported in the literature [23].
Examining the supramolecular structure of complex 1, we
find a series of intermolecular C–HꢀꢀꢀO and p–p stacking
interactions. In Fig. 2, the supramolecule exhibits a 1D
infinite chain structure formed by intermolecular C–HꢀꢀꢀO
hydrogen bonding. The C–O group acts as a bifurcated
acceptor. The H7ꢀꢀꢀO3 distance and the angle C7H7ꢀꢀꢀO3 are
Although there has been molecular weight evidence for
the tetrameric 16-membered macrocyclic rings in triorga-
notin phosphinates, and carboxylates [24], to the best of
our knowledge, no examples in triorganotin selenites
containing tetranuclear macrocycle construction have been
reported.
˚
2.64A and 125.9ꢁ, respectively. In Fig. 3, the intermolecular
p–p interactions produce a 2D plane along the bc plane. The
distance of the phenyl rings centroid from each pair of
Crystal structure of complex 2
˚
neighboring molecules is 3.870 A. The mean deviation angle
The molecular structure, 1D polymeric chain structure, and
of planes and the centroids are 22.9ꢁ and 23.4ꢁ, respectively,
2D supermolecular structure of complex 2 are illustrated in
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Struct Chem (2014) 25:949–958
Fig. 3 The 2D network of
complex 1 made up of
intermolecular weak p–p
interaction (the additional
carbon atoms of the trimethyltin
groups are omitted for clarity)
Figs. 4 and 5, respectively; selected bond lengths and bond
angles for this complex are given in Table 3. In the crys-
talline state, complex 2 adopts a 1D infinite zigzag chain
structure with a five-coordinated tin center, which is gen-
erated by the –O2SeC6H4-4-Et and Sn center. This structure
is very similar to [R3SnO2P(OC2H5)2]n [10]. The Sn atom
exists in a slightly distorted trigonal bipyramidal environ-
ment with the basal plane being defined by three carbon
groups and two O atoms derived from two symmetry
related, bridging –O2SeC6H4-4-Et ligands, the sum of the
trigonal angles is 3608, the corresponding axial-Sn-axial
angles [O(1)–Sn(1)–O(2) 176.73(11)], and the Sn atom lies
in the plane of the three C atoms within experimental error
[25]. The –O2SeR ligand symmetrically bridges two Sn
atoms forming indistinguishable Sn–O bond lengths
˚
˚
[Sn(1)–O(1) 2.184(3) A, Sn(1)–O(2) 2.247(3) A, which
lead to a 1D infinite chain structure as shown in the view of
Fig. 4 The molecular structure of complex 2
Fig. 5 The 2D supramolecular
structure of complex 2 made up
of intermolecular C–H…O
interactions
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Struct Chem (2014) 25:949–958
955
Fig. 6. The symmetrical bridging mode of coordination of
the –O2Se C6H4-4-Et ligand is reflected in the experi-
mentally equivalent Se–O bond distances [Se–O(1)
framework. Those hydrogen bonds play an important role in
the stabilization of the polymeric structure.
˚
˚
1.696(3) A, Se–O(2) #1 1.676(3) A]. The Se atom geom-
etry is pyramidal owing to the presence of a stereochemi-
cally active lone pair of electrons; there is no evidence of
an interaction between the Sn and Se atoms. Interestingly,
Sn atoms of complex 2 linked by ligands in anti–anti
conformation are arranged in zig–zag chain.
Crystal structure of complex 3
The molecular structure and 1D polymeric chain structure
of complex 3 are illustrated in Figs. 7 and 8, respectively,
and selected bond lengths and bond angles are given in
Table 4. As observed from Fig. 7, the asymmetric unit
contains two molecules A and B, which are different from
a crystallographic point of view. Each molecule of com-
plex 3 has crystallographic central symmetry, which cor-
responds to the idealized molecular symmetry. The
conformations of the two independent molecules are
almost the same, with only small differences in bond
lengths and bond angles (see table 4). Then we describe the
details of the complex structure of complex 3 with Sn(1) as
an example. In complex 3 the pentacoordinate Sn(1) atom
Futhermore, as can be seen from Fig. 5, the 2D supra-
molecular structure of complex 2 is further linked by inter-
molecular C–HꢀꢀꢀO weak interactions forming an infinite 2D
network structure. As shown in Fig. 5, the 1D chains are
connected via intermolecular interactions C(19)–H(19)ꢀꢀꢀ
˚
O(2)#3 [C(19)ꢀꢀꢀO(2)#3, 3.573(7) A; H(19)ꢀꢀꢀO(2)#3,
˚
2.668 A; C(19)–H(19)ꢀꢀꢀO(2)#3, 164.55ꢁ] into a 2D metal
˚
Table 3 Selected bond lengths (A) and angles (ꢁ) for complex 2
Complex 2
Sn(1)–C(9)
2.126(5) Sn(1)–O(1)
2.126(4) Sn(1)–O(2)
2.184(3)
2.247(3)
Sn(1)–C(15)
Sn(1)–C(21)
2.131(5) Se(1)–O(1)
1.696(3)
Se(1)–C(6)
1.940(5) Se(1)–O(2)#1
90.43(14) C(9)–Sn(1)–C(15)
96.80(15) C(9)–Sn(1)–C(21)
1.676(3)
C(9)–Sn(1)–O(1)
C(15)–Sn(1)–O(1)
C(21)–Sn(1)–O(1)
C(9)–Sn(1)–O(2)
C(15)–Sn(1)–O(2)
C(21)–Sn(1)–O(2)
Se(1)–O(1)–Sn(1)
118.33(19)
124.64(18)
91.82(16) C(15)–Sn(1)–C(21) 116.25(19)
88.05(14) O(1)–Sn(1)–O(2) 176.73(11)
86.47(15) O(2)#1–Se(1)–O(1) 102.83(16)
86.67(15) O(2)#1–Se(1)–C(6)
125.76(16) O(1)–Se(1)–C(6)
98.14(19)
98.49(17)
Se(1)#2–O(2)–Sn(1) 130.96(17)
Symmetry code for complex 2: #1 -x ? 1, y-1/2, -z ? 1/2
#2 -x ? 1, y ? 1/2, -z ? 1/2
Fig. 7 The molecular structure of complex 3
Fig. 6 The 1D infinite zigzag
chain of complex 2
123

956
Struct Chem (2014) 25:949–958
complexes [26], and approaches the Sn–O covalent bond
˚
length (2.13 A), but is much shorter than the sum of the
˚
Van der Waals radii of Sn and O (3.68 A) [27], which
proves that the O atom is coordinated to the tin atom by a
strong chemical bond. The Sn–C bond lengths [2.124(11)–
˚
2.125(10)A] are consistent with those reported in other
triorganotin derivatives [28].
As shown in Fig. 8, each [O2SeC6H4-2-Et]- ligand
bridges to two Sn centers by O atoms, and likewise each Sn
center interacts with two [O2SeC6H4-2-Et]- ligands, to
generate a two-fold helical chain along the b axis, and thus
complex 3 crystallizes in the chiral space group P21 as
˚
determined by X-ray diffraction. The pitch (10.218 A) of
this helical chain is slightly larger than that found in
[Me3Sn(SC6H4CO2)Me3Sn]2ꢀ(4,40-bipy) [29], which is
possibly due to the different molecular conformation and
bonding mode between the two complexes. Unfortunately,
the solvent molecules are not captured in the channels of
complex 3 due to the seriously compact structure, which is
obviously different from our previously reported organotin
helical complex, [(Ph3Sn)(C7H5ClNO2)] [8].
Fig. 8 The 1D chiral helical chain structure of complex 3 (the
additional carbon atoms of the methyltin groups are omitted for
clarity)
is surrounded axially by two oxygen atoms and equatori-
ally by three carbon atoms of the Sn–methyl groups in syn–
anti conformation. The Sn–O distance [2.237(7)–2.246(7)
Crystal structure of complex 4
The molecular structure and 1D polymeric chain structure
˚
A] is a little shorter than reported in other organotin
of complex 4 are illustrated in Figs. 9 and 10, respectively.
Table 4 Selected bond lengths
˚
Complex 3
(A) and angles (ꢁ) for complex 3
Sn(1)–C(20)
2.124(11)
2.125(10)
2.129(10)
2.237(7)
2.246(7)
1.679(7)
1.699(9)
1.914(5)
Sn(2)–C(10)
2.125(12)
2.125(12)
2.138(13)
2.211(8)
2.294(8)
1.690(7)
1.698(7)
1.919(5)
Sn(1)–C(22)
Sn(2)–C(11)
Sn(1)–C(21)
Sn(2)–C(9)
Sn(1)–O(4)
Sn(2)–O(2)
Sn(1)–O(3)#1
Sn(2)–O(1)#2
Se(1)–O(1)
Se(2)–O(4)
Se(1)–O(2)
Se(2)–O(3)
Se(1)–C(1)
Se(2)–C(12)
C(20)–Sn(1)–C(22)
C(20)–Sn(1)–C(21)
C(22)–Sn(1)–C(21)
C(20)–Sn(1)–O(4)
C(22)–Sn(1)–O(4)
C(21)–Sn(1)–O(4)
C(20)–Sn(1)–O(3)#1
C(22)–Sn(1)–O(3)#1
C(21)–Sn(1)–O(3)#1
O(4)–Sn(1)–O(3)#1
O(1)–Se(1)–O(2)
O(1)–Se(1)–C(1)
121.0(6)
C(10)–Sn(2)–C(11)
C(10)–Sn(2)–C(9)
C(11)–Sn(2)–C(9)
C(10)–Sn(2)–O(2)
C(11)–Sn(2)–O(2)
C(9)–Sn(2)–O(2)
C(10)–Sn(2)–O(1)#2
C(11)–Sn(2)–O(1)#2
C(9)–Sn(2)–O(1)#2
O(2)–Sn(2)–O(1)#2
O(4)–Se(2)–O(3)
O(4)–Se(2)–C(12)
O(3)–Se(2)–C(12)
Se(2)–O(3)–Sn(1)#4
Se(2)–O(4)–Sn(1)
119.1(6)
117.8(5)
121.1(5)
93.9(4)
90.1(4)
87.1(4)
90.4(4)
93.2(4)
85.2(4)
172.2(3)
104.0(4)
99.2(4)
99.0(4)
129.0(4)
127.0(4)
118.9(6)
121.8(6)
86.8(4)
94.9(4)
93.7(5)
85.5(4)
90.6(4)
88.3(4)
172.1(3)
104.4(4)
99.7(3)
99.4(3)
131.4(4)
128.5(4)
O(2)–Se(1)–C(1)
Symmetry code for complex 3:
#1 -x, y-1/2, -z; #2 -x, y-1/
2, -z ? 1; #3 -x, y ? 1/2, -
z ? 1; #4 -x,y ? 1/2, -z
Se(1)–O(1)–Sn(2)#3
Se(1)–O(2)–Sn(2)
123

Struct Chem (2014) 25:949–958
957
axial positions are occupied by the O atoms of the ligands
[axial angles: O(2)#1–Sn(1)–O(1) = 177.88(18)ꢁ#1: x, y,
z-1]. The axial angle of complex 4 is not 180ꢁ, which
proves the distortion of the geometry. Three methyl carbon
atoms occupy the equatorial plane. These Sn–O bond
˚
lengths [Sn(1)–O(1) = 2.267(10) A, Sn(1)–O(2)#1 =
˚
2.213(11) A] are a little longer than the Sn–O covalent
˚
bond lengths [2.038–2.115 A] [16]. The Sn–C distances
˚
[1.91(5)–2.24(4) A] are equal within experimental error
and are close to the single-bond value for a trigonal–
bipyramidal tin atom [25]. Unlike many polymeric trior-
ganotin selenites that adopt zigzag conformations, the tin
centers in the polymeric chain of complex 4 are arranged in
a linear manner.
Fig. 9 The molecular structure of complex 4
TGA studies
Selected bond lengths and bond angles for these complexes
are given in Table 5. In the crystalline state, complex 4
adopts an infinite 1D polymeric chain structure, which is
generated by the bidentate bridging selenite ligands and the
Sn center. The Sn atom exists in a distorted trigonal
bipyramidal environment with two O atoms and three C
atoms, linked by ligands in anti–anti conformation. The
To study the stability of complexes 1–4, thermogravimetric
analysis (TGA) was perfomed in the temperature range of
50–500 ꢁC under N2 atmosphere. The TGA curves of
complexes 1–4 exhibit one continuous weight loss stage in
the range of 190–390 ꢁC. In general, complexes 1–4
exhibit good thermal stability.
Fig. 10 The 1D infinite linear polymeric chain of complex 4
Table 5 Selected bond lengths
Complex 4
˚
(A) and angles (ꢁ) for complex 4
Sn(1)–C(9)
2.130(6)
2.156(6)
2.140(6)
1.989(7)
87.3(5)
Sn(1)–O(1)
2.267(10)
2.213(11)
1.628(10)
1.712(10)
Sn(1)–C(15)
Sn(1)–O(2) #1
Se(1)–O(1)
Sn(1)–C(21)
Se(1)–C(1)
Se(1)–O(2)
C(9)–Sn(1)–O(1)
C(15)–Sn(1)–O(1)
C(21)–Sn(1)–O(1)
C(9)–Sn(1)–O(2) #1
C(15)–Sn(1)–O(2) #1
C(21)–Sn(1)–O(2) #1
Se(1)–O(1)–Sn(1)
C(9)–Sn(1)–C(15)
C(9)–Sn(1)–C(21)
C(21)–Sn(1)–C(15)
O(2)#1–Sn(1)–O(1)
O(1)–Se(1)–O(2)
O(1)–Se(1)–C(1)
O(2)–Se(1)–C(1)
116.7(2)
89.2(5)
125.9(2)
117.2(2)
177.88(18)
102.2(2)
103.2(4)
101.3(5)
89.4(4)
91.0(5)
90.5(5)
92.6(4)
143.9(5)
136.6(5)
Symmetry code for complex 4:
#1 x, y, z-1; #2 x, y, z ? 1
Se(1)–O(2)–Sn(1)#2
123

958
Struct Chem (2014) 25:949–958
2. Chandrasekhar V, Nagendran S, Baskar V (2002) Coord Chem
Rev 235:1
Conclusion
3. Rao CNR, Natarajan S, Vaidhyanathan R (2004) Angew Chem
116:1490
4. Gielen M, Khloufi A, Biesemans M, Willem R, Meunier-Piret J
(1992) Polyhedron 11:1861
5. Braunstein P, Morise X (2000) Chem Rev 100:3541
6. Chandrasekhar V, Gopal K, Sasikumar P, Thirumoorthi R (2005)
Coord Chem Rev 249:1745
7. Chandrasekhar V, Singh P (2010) Cryst Growth Des 10:3077
8. Zhang JH, Zhang RF, Wang QF, Ma CL, Wang DQ (2010) Inorg
Chim Acta 363:3616
9. Ma CL, Li QL, Guo MJ (2009) J Organomet Chem 694:4230
10. Zhang RF, Yang MQ, Ma CL (2008) J Organomet Chem
693:2551
11. Shen L, Cao Y, Hu CW (2009) Chin Chem Lett 20:370
12. Ma CL, Guo MJ, Ru J, Zhang RF, Wang QF (2011) Inorg Chim
Acta 378:213
13. Zhang RF, Ru J, Li ZX, Ma CL, Zhang JP (2011) J Coord Chem
64:4122
14. Kloc K, Mlochowski J, Syper L (1989) Liebigs Ann Chem
54:811
In summary, a series of triorganotin(IV) complexes based
on 4-ethylbenzeneseleninic acid and 2-ethylbenzenesele-
ninic acid ligands have been synthesized and characterized
by elemental analyses, IR, NMR spectra and X-ray single-
crystal diffraction. Both the spectra and crystal structures
show that when 4-ethylbenzeneseleninic acid and 2-ethyl-
benzeneseleninic acid react with triorganotin(IV) chloride,
they can form tetranuclear macrocyclic complexes, 1D
helic chains, and 2D network polymers with metal–organic
structures by substituting the chlorine atom. In general, the
tin atoms in these complexes are all five-coordinated and
display a trigonal bipyramid geometry. This phenomenon
may be related to the spatial hindrance of the triorganotin
group. The supramolecular structures described in this
paper demonstrate that weak intermolecular interactions
have enormous potential for assembling discrete molecular
systems in which the subunits are organometallic com-
plexes. With the aim to design and synthesize organotin
complexes with desired structures and high anti-tumor
activities, more work is required to explore new complexes
using selenite acid ligands attached with different tin salts.
15. Reich HJ, Jasperse CP (1988) J Org Chem 53:2389
16. Sandhu GK, Hundal R (1991) J Organomet Chem 412:31
17. Diallo W, Diop CAK, Diop L, Mahon MF, Molloy KC, Russo U,
Biesemans M, Willem R (2007) J Organomet Chem 692:2187
18. Li WJ, Du DF, Liu SS, Zhu CG, Sakho AM, Zhu DS, Xu L
(2010) J Organomet Chem 695:2153
19. Chandrasekhar V, Muralidhara MG, Justin Thomas KR, Tiekink
ERT (1992) Inorg Chem 31:4707
20. McCullough JD, Gould ES (1949) J Am Chem Soc 71:674
21. Holecek J, Nadvornik M, Handlir K, Lycka A (1986) J Organo-
ment Chem 315:299
Supplementary material
22. Amini MM, Azadmehr A, Alijani V, Khavasi HR, Hajiashrafi T,
Kharat AN (2009) Inorg Chim Acta 362:355
23. Piacenza M, Grimme S (2005) Chem Phys Chem 6:1554
24. Newton MG, Haiduc I, King RB, Silvestru C (1993) Chem
Commun 18:1229
25. Ma CL, Zhang BY, Zhang SL, Zhang RF (2011) J Organomet
Chem 696:2165
26. Willem R, Bouhdid A, Mahieu B, Ghys L, Biesemans M, Tiekink
ERT, de Vos D, Gielen M (1997) J Organomet Chem 531:151
27. Bondi A (1964) J Phys Chem 68:441
CCDC no. 928636 (1), 928637 (2), 928638 (3), 928639 (4)
contain the supplementary crystallographic data for this
paper. Copies of the data can be obtained free of charge on
application to the Director, 12 Union Road, Cambridge, CB2
1EZ, UK (Fax: ?44-1223-336033; deposit@ccdc.cam.ac.uk
or http://www.ccdc.cam.ac.uk).
Acknowledgments We thank the National Natural Science Foun-
dation of China (21371087) and Natural Science Foundation of
Shandong Province (ZR2010BL019) for financial support.
28. Ma CL, Sun JF, Shi Y, Zhang RF (2005) J Organomet Chem
690:1560
29. Ma CL, Zhang QF, Zhang RF (2005) J Organomet Chem
690:3033
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