Monoorganooxotin cage, diorganotin ladders, diorganotin double chain and triorganotin single chain formed with phosphonate and arsonate ligands

Article abstract of DOI:10.1039/b915255e

The solvothermal reaction of n-BuSn(O)OH with PhPO₃H₂ afforded the hexanuclear monoorganooxotin phosphonate cage, {[(n-BuSn) ₃(MeO)₃O]₂(O₃PPh) ₄}·MeOH 1. When the n-Bu₂Sn(PhCO₂) ₂ precursor reacted with PhPO₃H₂ in a 1:1 stoichiometric ratio, the diorganotin phosphonate ladder [n-Bu ₂SnO₃PPh]_n2 was obtained. The reaction of [n-Bu₂(PrO)Sn]₂O with 4-OH-3-NO₂-C ₆H₃AsO₃H₂ affords the diorganotin arsonate ladder [n-Bu₂Sn(4-OH-3-NO₂-C₆H ₃AsO₃)]_n3, while the reaction of [n-Bu ₂(PrO)Sn]₂O with 4-NO₂-C₆H ₄AsO₃H₂ and 4-Me-C₆H ₄SO₃H gives an diorganotin double chain [n-Bu ₂Sn(4-Me-C₆H₄SO₃)(4-NO ₂-C₆H₄AsO₃H)]_n4, which contains both sulfonate and arsonate ligands. The reaction of 4-NO ₂-C₆H₄AsO₃H₂, EtONa, and Ph₃SnCl yields a new triorganotin arsonate single chain [(Ph ₃Sn)₄(4-NO₂-C₆H₄AsO ₃)₂·H₂O]_n5. The NMR ( ¹H, ¹³C, ¹¹⁹Sn) spectra of compounds 1 and 4 were studied. The Royal Society of Chemistry 2010.

Full text of DOI:10.1039/b915255e

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www.rsc.org/dalton | Dalton Transactions
Monoorganooxotin cage, diorganotin ladders, diorganotin double chain and
triorganotin single chain formed with phosphonate and arsonate ligands†
Yun-Peng Xie, Jian-Fang Ma,* Jin Yang* and Min-Zhong Su
Received 27th July 2009, Accepted 29th October 2009
First published as an Advance Article on the web 11th December 2009
DOI: 10.1039/b915255e
The solvothermal reaction of n-BuSn(O)OH with PhPO3H2 afforded the hexanuclear
monoorganooxotin phosphonate cage, {[(n-BuSn)3(MeO)3O]2(O3PPh)4}·MeOH 1. When the
n-Bu2Sn(PhCO2)2 precursor reacted with PhPO3H2 in a 1 : 1 stoichiometric ratio, the diorganotin
phosphonate ladder [n-Bu2SnO3PPh]n 2 was obtained. The reaction of [n-Bu2(PrO)Sn]2O with
4-OH-3-NO2-C6H3AsO3H2 affords the diorganotin arsonate ladder [n-Bu2Sn(4-OH-3-NO2-
C6H3AsO3)]n 3, while the reaction of [n-Bu2(PrO)Sn]2O with 4-NO2-C6H4AsO3H2 and 4-Me-C6H4SO3H
gives an diorganotin double chain [n-Bu2Sn(4-Me-C6H4SO3)(4-NO2-C6H4AsO3H)]n 4, which contains
both sulfonate and arsonate ligands. The reaction of 4-NO2-C6H4AsO3H2, EtONa, and Ph3SnCl yields
a new triorganotin arsonate single chain [(Ph3Sn)4(4-NO2-C6H4AsO3)2·H2O]n 5. The NMR (1H, 13C,
119Sn) spectra of compounds 1 and 4 were studied.
four new types of organotin/tin–oxygen arsonate clusters were
Introduction
obtained.7c
Organostannoxanes are a very interesting class of compounds
The suitability of pre-synthesized organotin compounds to
which have been attracting interest in view of their remarkable
serve as precursors for new types of organotin compounds
structural diversity1 as well as their utility as catalysts2 in
organic reactions. So far, organotin carboxylates, phosphinates
and sulfonates have been extensively prepared and structurally
characterized.3-5 But very few organotin compounds based on
is currently being actively investigated. For instance, Shankar
et al. have synthesized a series of novel diorganotin derivatives
by utilizing di-n-butyltin(alkoxy)alkanesulfonates as precursors.8
Among the organotin precursors, distannoxane [n-Bu2(PrO)Sn]2O
phosphonate and arsonate ligands are known because of the
is an attractive candidate precursor, where the PrO groups are
difficulty in obtaining their crystals. Particularly, crystal structures
of the polymeric organotin phosphonates and arsonates, such
easily replaced by other ligands, leading to new types of organotin
structures. For example, when the [n-Bu2(PrO)Sn]2O precursors
as chain and ladder, have not been documented, and only
were treated with methylphosphonic acid and phenylphosphonic
were surmised through the IR, Mo¨ssbauer, and X-ray powder
acid, compounds [Bu2Sn(HO3PMe)2]2 and Bu2Sn(O3PPh) were
diffraction.6 Therefore, exploration of the crystal structures of the
polymeric organotin phosphonates and arsonates attracted our
intense interest.
obtained, respectively.9a However, only the structure of the former
was determined by single-crystal X-ray diffraction.
The above results stimulated our research interest toward
further exploring the structural variations of the organotin
phosphonates and arsonates. In this work, the solvothermal
reaction of n-BuSn(O)OH with PhPO3H2 in methanol leads
to the formation of {[(n-BuSn)3(MeO)3O]2(O3PPh)4}·MeOH 1,
while the reaction of n-Bu2Sn(PhCO2)2 with PhPO3H2 gives [n-
Bu2SnO3PPh]n 2. The reaction of [n-Bu2(PrO)Sn]2O precursor
with 4-OH-3-NO2-C6H3AsO3H2 affords the diorganotin arsonate
ladder [n-Bu2Sn(4-OH-3-NO2-C6H3AsO3)]n 3, while the reaction
of [n-Bu2(PrO)Sn]2O precursor with 4-NO2-C6H4AsO3H2 and
4-Me-C6H4SO3H gives an diorganotin double chain [n-Bu2Sn(4-
Me-C6H4SO3)(4-NO2-C6H4AsO3H)]n 4. The reaction of 4-NO2-
C6H4AsO3H2, EtONa, and Ph3SnCl yields a new triorganotin
arsonate single chain [(Ph3Sn)4(4-NO2-C6H4AsO3)2·H2O]n 5.
Development of new synthetic strategies is important for
the discovery of new structural types in organotin compounds.
In this regard, we have been endeavouring to develop new
synthetic approaches for organotin compounds. Accordingly, a
series of new organotin clusters were firstly obtained through a
solvothermal method.7 For example, the solvothermal reaction
of (n-Bu2SnO)x with 1,1¢-ferrocenedicarboxylic acid gave the first
tin–oxygen cluster Sn8O4L6 (H2L = 1,1¢-ferrocenedicarboxylic
acid).7a The solvothermal reaction of Bz3SnCl with monosodium
phenylphosphonate yielded the first organotin phospho-
nate oligomer, [Na6(CH3OH)2(H2O)][{(BzSn)3(PhPO3)5(m3-O)-
(CH3O)}2Bz2Sn]·CH3OH.7b When the triphenyltin compounds
were treated with arsonic acids under solvothermal conditions,
Results and discussion
Key Lab of Polyoxometalate Science, Department of Chemistry, North-
east Normal University, Changchun, 130024, People’s Republic of China.
E-mail: jianfangma@yahoo.com.cn yangjinnenu@yahoo.com.cn
Synthesis and characterization of compounds 1–5
† Electronic supplementary information (ESI) available: Five X-ray crys-
tallographic files (CIF), selected bond distances and angles. CCDC
reference numbers 737801–737805. For ESI and crystallographic data in
CIF or other electronic format see DOI: 10.1039/b915255e
Compound 1 was obtained through the reaction of n-BuSn(O)OH
with PhPO3H2 in methanol at 140◦ C (Scheme 1). Upon exposure
to air, crystals of compound 1 became opaque within minutes,
1568 | Dalton Trans., 2010, 39, 1568–1575
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Molecular structure of {[(n-BuSn)3(MeO)3O]2(O3PPh)4}·MeOH
(1)
The crystal data of 1–5 are summarized in Table 1, whereas selected
bond lengths and angles are given in Table S1 (see ESI†).
In view of the isolation of the organotin phosphonate
{Na6(CH3OH)2(H2O)} {(BzSn)3(PhPO3)5(m3-O)(CH3O)]2Bz2Sn}·
CH3OH, we performed an analogous solvothermal reaction. The
hexanuclear cage {[(n-BuSn)3(MeO)3O]2(O3PPh)4}·MeOH 1 was
obtained through the reaction of n-BuSn(O)OH with PhPO3H2 in
methanol at 140◦ C (Scheme 1). As shown in Fig. 1, 1 contains
two tritin units [(n-BuSn)3(O)(MeO)3], where three tin atoms (Sn1,
Sn2 and Sn3) are joined together by a m3-oxygen ligand. Two
adjacent tin atoms are further connected by one m2-MeO- group.
The two [(n-BuSn)3(O)(MeO)3] units are linked through four
Scheme 1 Synthetic route of compound 1.
indicating a loss of solvent. The syntheses of compounds 2–5
are summarized in Schemes 2 and 3. The single crystals of 2–4
were directly obtained by crystallization of the respective reaction
mixtures at room temperature, while the crystals of compound 5
were obtained at a refluxing temperature.
2-
PhPO3 ions, affording the first hexanuclear monoorganooxotin
phosphonate cage. Each of the phenylphosphonate groups shows
the m3-bridging coordination mode. All of the tin atoms are
hexacoordinated, bonding to one carbon atom and five oxygen
atoms in octahedral coordination geometries. The average m3-
˚
O–Sn bond length is 2.06 A, while the average m2-O–Sn bond
˚
length is 2.15 A. The average Sn–O distance involving the bridging
˚
phosphonate is 2.08 A. These values are comparable to those
observed in other organotin phosphonate clusters.7b
Fig. 1 Molecular structure of 1. All H atoms have been omitted for clarity.
Symmetry code: #1 1-x, 1-y, z.
A
hexanuclear monoorganooxotin phosphite cage {[(n-
BuSn)3(PhO)3O]2(O3PPh)4} and a hexanuclear inorganic tin-
oxygen arsonate cage {[Sn3Cl3(O)(MeO)3]2(2-NO2-C6H4AsO3)4}
have been reported.7d,7e The compound 1 is clearly related to
the two previously reported hexanuclear structures, however,
there are a number of significant differences. In comparison
with the reported {[(n-BuSn)3(PhO)3O]2(O3PPh)4}, the m2-PhO-
groups of the [(n-BuSn)3(O)(PhO)3] unit are replaced by the m2-
MeO- groups of the [(n-BuSn)3(O)(MeO)3] for 1. The two [(n-
BuSn)3(O)(PhO)3] units are further connected to each other by
Scheme 2 Synthetic routes of compounds 2–5.
2-
four HPO3 ions, affording the hexanuclear monoorganooxotin
phosphite cage. However, in contrast to {[Sn3Cl3(O)(MeO)3]2(2-
NO2-C6H4AsO3)4}, the Cl- groups of the [Sn3Cl3(O)(MeO)3] unit
are replaced by n-Bu groups of the [(n-BuSn)3(O)(MeO)3] for
1. The two [Sn3Cl3(O)(MeO)3] units are further linked through
2-
four 2-NO2-C6H4AsO3 ions, giving the hexanuclear tin-oxygen
arsonate cage. Thus, compound 1 represents the hexanuclear
Scheme 3 Synthetic route of compound 5.
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monoorganooxotin phosphonate cage.
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Table 1 Crystal data and structure refinements for compounds 1–5
1
2
Formula
FW
Cryst. syst.
C55H96O21P4Sn6
1929.34
Triclinic
¯
P1
12.437(7)
12.829(6)
14.246(6)
63.359(14)
82.908(19)
70.228(19)
1910.8(16)
1
C42H69O9P3Sn3
1166.95
Monoclinic
P21/c
14.794(3)
21.870(5)
17.051(4)
90
109.379(8)
90
5204.4(19)
4
Space group
˚
a/A
˚
b/A
˚
c/A
a (◦)
b (◦)
g (◦)
3
˚
V/A
Z
Dc/g cm-3
1.677
954
1.489
2352
F(000)
Reflns collected/unique
GOF on F2
Rint
R1[I > 2s(I)]
R1[all data]
wR2[I > 2s(I)]
wR2[all data]
18475/8514
1.093
0.0253
0.0362
0.0438
0.1152
0.1211
3
47860/11628
1.050
0.0646
0.0525
0.0857
0.1374
0.1605
4
5
Formula
FW
C14H22AsNO6Sn
493.94
C21H30AsNO8SSn
649.92
C84H70As2N2O11Sn4
1908.02
Cryst. syst.
Monoclinic
C2/c
Triclinic
P1
Triclinic
P1
¯
¯
Space group
˚
a/A
21.3171(10)
16.9883(11)
12.3270(15)
90
122.929(2)
90
3746.9(5)
8
1.751
9.393(6)
10.437(5)
14.206(6)
91.074(14)
92.744(19)
107.485(18)
1326.0(1)
2
1.628
650
38320/17825
1.036
12.806(3)
14.635(4)
23.623(7)
80.774(11)
88.419(10)
65.454(10)
3971.4(19)
2
˚
b/A
˚
c/A
a (◦)
b (◦)
g (◦)
3
˚
V/A
Z
Dc/g cm-3
1.588
1874
F(000)
1952
13180/6007
1.054
Reflns collected/unique 9411/3329
GOF on F2
1.038
Rint 0.0340 0.0553 0.0483
R1[I > 2s(I)]
0.0514
0.0707
0.1396
0.1535
0.0507
0.0839 0.1083
0.0992
0.0613
0.1414
R1[all data]
wR2 [I > 2s(I)]
wR2 [all data]
0.1036 0.1667
Molecular structure of [n-Bu2SnO3PPh]n (2)
To the best of our knowledge, the only studies on
dibutyltinphosphonates with a basic structural unit of the
type Bu2SnO3PR were made at the end of the 1960s by Ridenour
et al. (R = C6H13, CH2C6H5, C8H17),9b Freireich et al. (R = C6H5)9c
and Ribot et al. (R = C6H5, CH3).9a However, crystals have not
been obtained for these compounds. Here, the n-Bu2Sn(PhCO2)2
precursor reacted with PhPO3H2 in a 1 : 1 stoichiometric ratio, the
ladder-like dibutyltinphosphonate chain [n-Bu2SnO3PPh]n 2 was
obtained (Scheme 2). As shown in Fig. 2a, the asymmetric unit of
2 is composed of three crystallographically unique tin atoms (Sn1
to Sn3) and three phenylphosphonate ligands which are bound
to the three tin atoms in two different coordination modes. The
phenylphosphonate group (P2) is bound to three tin atoms (Sn1 to
Sn3). On the other hand, the phenylphosphonate group (P1or P3)
is bound to two tin atoms (Sn1, Sn3 for P1 and Sn2, Sn3 for P3)
through its two O atoms contributing to the formation of the eight-
membered ring (Sn2P2O4), and it employs the third oxygen atom
Fig. 2 (a) Structure of the asymmetric unit of 2. (b) Molecular structure of
[n-Bu2SnPhPO3]n, 2. (c) Sn–O–P core of 2 showing a ladder-like structure
along the b-axis. Symmetry codes: #1 2-x, 2-y, -z+1; #2 1-x, 2-y, -z.
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to coordinate to the adjacent asymmetric unit. The cumulative
effect of the coordination of the phenylphosphonates leads to
the formation of the ladder-like diorganotin phosphonate chain
(Fig. 2b). The chain is built from edge-sharing eight-membered
rings (Sn2P2O4), with strictly alternating Sn and P nodes.
However, the chain is non-planar, when looking along the a-axis
(Fig. 2c). Each tin is five-coordinate with a C2O3 coordination
environment. The geometry around each tin is distorted trigonal
bipyramid (oxygen atoms in the apical position, angle O–Sn–O =
◦
˚
170.6(2)–175.8(2) ). The average Sn–O bond length is 2.16 A.
It is noteworthy that the architecture of the present diorganotin
phosphonate chain is entirely different from that of the reported
diorganotin phosphinate chain {[(n-Bu2Sn)2(OH)][cycPO2]3}n
(cycPO2H = 1,1,2,3,3-pentamethyltrimethylene phosphinic acid),
consisting of alternate planar six- (Sn2PO3), and eight-membered
rings (Sn2P2O4).9 The adjacent six- and eight-membered rings are
nearly coplanar. The bridging bidentate mode of phosphinate
ligands leads to the formation of the chain. However, in 2
the phenylphosphonate groups, in unusual dianionic tridentate
modes, linked the n-Bu2Sn groups into a non-planar ladder-
like chain structure, which is only built from eight-membered
rings (Sn2P2O4). Also, the eight-membered ring (Sn2P2O4) is
non-planar. Obviously, the third coordinating oxygen atom of
the phenylphosphonate unit plays a significant role in the
formation of the diorganotin phosphonate chain of 2. On
the other hand, compound [Me2Sn(m3-dipp)]n (dipp-H2 = 2,6-
diisopropylphenylphosphate) has been reported.9a In [Me2Sn(m3-
dipp)]n, each dipp ligand bridges three different tin atoms to form
an infinite ladder-chain structure. In comparison with [Me2Sn(m3-
dipp)]n, the dipp groups are replaced by phenylphosphonates for 2.
Fig. 3 (a) Structure of the asymmetric unit of 3. (b) Molecular structure
of 3 along the b-axis. (c) Molecular structure of 3 along the a-axis. The
a-carbon of phenyl ring (As–Ph) is reserved, and the other atoms, which
are omitted for clarity. Symmetry codes: #1 1-x, y, -z+3/2; #2 x, -y, z+1/2;
#3
x, -y+1, z-1/2.
between chains, forming a two-dimensional supramolecular struc-
ture (Fig. 4). The oxygen atoms (O5) and the hydrogen atoms
(H4) are involved in these hydrogen-bonding interactions to form
a 4-membered hydrogen-bonding ring. The distances of O ◊ ◊ ◊ O
interactions for O4–H4 ◊ ◊ ◊ O5 and O4–H4 ◊ ◊ ◊ O5#1 are 2.60(1) and
˚
Consequently, the P–O bonds [1.50 (5)–1.55(5) A] in 2 are longer
˚
than the ones [1.49 (7)–1.51(6) A] in [Me2Sn(m3-dipp)]n.
˚
3.01(2) A, respectively (Table 2).
Molecular structure of [n-Bu2Sn(4-OH-3-NO2-C6H3AsO3)]n (3)
The reaction of [n-Bu2(PrO)Sn]2O with 4-OH-3-NO2-
C6H3AsO3H2 in a 1 : 2 molar ratio affords a diorganotin
arsonate ladder [n-Bu2Sn(4-OH-3-NO2-C6H3AsO3)]n 3. X-ray
crystallographic study reveals that the structure of 3 shows an
infinite ladder. To the best of our knowledge, there have been
no reports on the crystal structures of diorganotin arsonates,
and therefore the diorganotin arsonate ladder of 3 was firstly
found in organotin arsonate compounds. As shown in Fig. 3a,
the asymmetric unit of 3 is composed of one crystallographically
unique tin atom (Sn1) and one arsonate ligand. The arsonate
group is bound to the tin atom (Sn1) through its one O atom,
and it employs the remaining two oxygen atoms to coordinate to
the two adjacent asymmetric units. The m3-O3As bonding mode
of arsonates leads to the formation of the distorted diorganotin
arsonate ladder running along the b-axis (Fig. 3b). The ladder
is built from edge-sharing eight-membered rings (Sn2As2O4),
with strictly alternating Sn and As nodes. However, the ladder
is non-planar, when looking along the a-axis (Fig. 3c). Each
tin atom is in a distorted trigonal bipyramid coordination
environment surrounded by three arsonate-oxygen atoms and
two carbon atoms of two of the n-butyl groups. The average Sn–O
Fig. 4 The two-dimensional supramolecular network structure of 3. The
hydrogen atoms which are not involved in hydrogen-bonding interactions
are omitted for clarity. The butyl groups on tin are omitted except for the
carbon atoms bonded to tin atoms.
Compounds 2 and 3 are 1D polymers with similar architectures.
Two polymeric chains are built from edge-sharing eight-membered
rings Sn2E2O4 (E = P or As), with strictly alternating Sn and E
nodes. It is noteworthy that polymeric chains of compounds 2 and
3 display beautiful sinusoidal ruffles (Fig. 2c and Fig. 3c), and the
period of compound 3 is shorter than that of compound 2.
Molecular structure of [n-Bu2Sn(4-Me-C6H4SO3)(4-NO2-
C6H4AsO3H)]n (4)
˚
bond length is 2.11 A.
In addition, there are intramolecular hydrogen bonding
(O4–H4 ◊ ◊ ◊ O5) and intermolecular interactions (O4–H4 ◊ ◊ ◊ O5#1)
The reaction of [n-Bu2(PrO)Sn]2O with 4-NO2-C6H4AsO3H2 and
4-Me-C6H4SO3H gives an unusual diorganotin double chain
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Table 2 Hydrogen-bonding parameters for compounds 3 and 4
˚ ˚
D ◊ ◊ ◊ A/A H ◊ ◊ ◊ A/A D-H ◊ ◊ ◊ A(deg) Symmetry
D-H ◊ ◊ ◊ A
Compound 3
O4-H4 ◊ ◊ ◊ O5
2.60(1)
3.01(2)
1.90
2.33
141.4
140.4
O4-H4 ◊ ◊ ◊ O5#1
1-x, -y, 2-z
Compound 4
O6-H6 ◊ ◊ ◊ O3#1
2.64(5)
2.05
2.48
2.54
2.56
128.8
166.7
137.8
167.0
2-x, 1-y, 2-z
2-x, 1-y, 2-z
2-x, -y, 2-z
2-x, 1-y, 3-z
C11-H11 ◊ ◊ ◊ O3#1 3.39(8)
C21-H21 ◊ ◊ ◊ O6#2 3.29(8)
C13-H13 ◊ ◊ ◊ O8#3 3.47(1)
[n-Bu2Sn(4-Me-C6H4SO3)(4-NO2-C6H4AsO3H)]n 4. A part of the
molecular structure of 4 corresponds to a dimer based on an
eight-membered ring formed by the m2-O2As bonding mode of
the hydrogenarsonate group. Further, the sulfonate groups act in
a m2-O2S bonding mode to form a weak bond with a tin atom
of the neighboring dimer, resulting in the formation of a double
chain comprising alternate eight-membered rings being formed by
the hydrogenarsonate and sulfonate ligands, respectively (Fig. 5).
Each tin atom adopts a distorted octahedral geometry with the
SnO4 core occupying the basal plane and trans disposition of n-
Fig. 6 Three-dimensional supramolecular assembly of 4 formed from
O–H ◊ ◊ ◊ O and C–H ◊ ◊ ◊ O interactions. (a) View showing part of the
supramolecular assembly of 4. (b) View showing the three-dimensional
supramolecular architecture.
ther, the two-dimensional supramolecular networks are further
interconnected by intermolecular interactions (C13–H13 ◊ ◊ ◊ O8#3)
to give a three-dimensional supramolecular architecture (Fig. 6b).
˚
butyl groups. The mean Sn–OS bond lengths [2.45(1)–2.53(2) A]
across the two sulfonate groups are found to be much longer than
The distance of the C13 ◊ ◊ ◊ O8#3 interaction is 3.47(1) A.
˚
˚
those observed for Sn–OAs bonds [2.05(1)–2.12(2) A].
Molecular structure of [(Ph3Sn)4(4-NO2-C6H4AsO3)2·H2O]n (5)
Through the reaction of 4-NO2-C6H4AsO3H2, EtONa and
Ph3SnCl, a new triorganotin arsonate single chain [(Ph3Sn)4(4-
NO2-C6H4AsO3)2·H2O]n 5 was obtained. As shown in Fig. 7, the
adjacent triorganotin motifs (Sn1 and Sn2) are bridged by the m2-
O2As bonding mode of arsonate groups to form a single chain.
The remaining oxygen atoms are bound to the other triorganotin
motifs (Sn3 and Sn4). Thus, the geometries of all the tin atoms
involved can be classified into two types: the five-coordinate tin
(Sn1 and Sn2) and the four-coordinate tin (Sn3 and Sn4). The tin
atom (Sn1 or Sn2) is trigonal bipyramidal (C3O2 coordination en-
vironment), with the apical positions being taken up by the oxygen
atoms of two different arsonate ligands. The apical O–Sn–O angle
is almost linear. The tetrahedral coordination geometry of Sn3 is
defined by three C atoms of the phenyl groups and one O atom
of the arsonate ligand. However, Sn4 is weakly coordinated by
Fig. 5 The structure of complex 4. All H atoms have been omitted for
clarity. Symmetry codes: #1 x, y-1, z; #2 x, y+1, z.
It is noteworthy that the architecture of 4 is entirely different
from that of 3. In 4, the hydrogenarsonate and sulfonate ligands
show the m2-bridging coordination modes. Each tin atom is six-
coordinate with a C2O4 coordination environment. However, in 3,
all the arsonate ligands show the m3-bridging coordination modes.
Each tin is five-coordinate with a C2O3 coordination environment.
Obviously, the third coordinating oxygen atom of the arsonate unit
plays a significant role in the formation of 3. However, in 4,
the introduction of sulfonate ligands is a critical factor in the
formation of the double chain.
˚
one water molecule [Sn–O = 2.77(2) A]. Although the long Sn–O
distances are well inside the sum of the van der Waals radii of the
Compound 4, which contains a 4-nitro substituent on the aro-
matic moiety, shows a three-dimensional supramolecular assembly
formed by O–H ◊ ◊ ◊ O and C–H ◊ ◊ ◊ O interactions (Fig. 6). This
can be understood in the following way. These one-dimensional
chains are interconnected through three intermolecular interac-
tions (O6-H6 ◊ ◊ ◊ O3#1, C11-H11 ◊ ◊ ◊ O3#1 and C21-H21 ◊ ◊ ◊ O6#2)
affording a two-dimensional supramolecular structure (Fig. 6a).
The distances of the O6 ◊ ◊ ◊ O3#1, C11 ◊ ◊ ◊ O3#1 and C21 ◊ ◊ ◊ O6#2
Fig. 7 The structure of complex 5. [The a-carbon of phenyl ring (Sn–Ph)
is reserved, and the other carbons, which are omitted for clarity.] Symmetry
codes: #1 1+x, y, z; #2 x-1, y, z.
˚
interactions are 2.64(5), 3.39(8) and 3.29(8) A, respectively. Fur-
1572 | Dalton Trans., 2010, 39, 1568–1575
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˚
the structure type of 4 was not found in Scheme 4. By carefully
observing the structure, we found that the double chain contains
the diorganotin arsonate dimer which is entirely different from that
of Scheme 4(a). In 4, two arsonates, in m2-O2As bonding mode,
bridge two tin atoms to yield a dimer, while the dimer depicted
in Scheme 4(a) was formed by the m3-O3As bonding mode of
arsonate group. The structure of 5 shows a triorganotin arsonate
single chain structure. The whole structure of 5 was similar to
diorganotin arsonate single chains surmised in Schemes 4(b) and
4(c). However, the coordination modes of arsonates in 5 differ
from those of Schemes 4(b) and 4(c). The structure of 5 indicates
that the reaction of triorganotin with arsonate also results in a
single chain.
Sn and O atoms (ca. 3.6 A), there does not appear to be any major
distortion of the tetrahedral Sn-coordination geometry as a result
of this contact. The average Sn–OAs bond length is 2.13 A. All the
˚
arsonate groups show the m3-bridging coordination modes.
In our previous work, the solvothermal reaction of Ph3SnCl
with 4-NO2-C6H4AsO3H2 yielded an inorganic tin-oxygen cluster
[Sn3Cl3(m3-O)(EtO)3]2(4-NO2-PhAsO3)4.7c The reaction proceeded
with complete dearylation of triphenyltin compound. However,
the reaction of 4-NO2-C6H4AsO3H2, EtONa, and Ph3SnCl at a
refluxing temperature gave the new triorganotin arsonate single
chain, [(Ph3Sn)4(4-NO2-C6H4AsO3)2·H2O]n 5. In contrast to the
solvothermal reaction, reaction conditions used for obtaining 5
are relatively mild, and the cleavage of Sn–Ph bonds does not
occur. The result reveals that the reaction conditions played an
important role in the formation of organotin arsonates.
1H, 13C and 119Sn NMR spectra
Notably, the possible structures of the diorganotin arsonates
and phosphonates have been surmised by Cunningham et al.
through IR, Mo¨ssbauer, and X-ray powder diffraction.6h As shown
in Scheme 4, the possible structures include a discrete dimer
[Scheme 4(a)], two singe chains [Schemes 4(b) and 4(c)], a ladder
[Scheme 4(d)] and a polymer [Scheme 4(e)]. In Scheme 4(a),
the dimer is composed of two tin atoms and two arsonate (or
phosphonate) ligands which are bound to the two tin atoms in
the m3-O3As (or m3-O3P) binding mode. In the single chain of
Scheme 4(b), the four-coordinate tin atoms are bridged by the ar-
sonates in the m2-O2As bonding mode (or phosphonates in m2-O2P
bonding mode). In Scheme 4(c), the single chain is similar to that
of Scheme 4(b), whereas the free oxygen atoms of arsonate (or
phosphonate) groups in Scheme 4(b) coordinate to neighbouring
tin atoms. All tin atoms are five-coordinated. When each arsonate
(or phosphonate) ligand is bound to the three tin atoms in m3-O3As
(or m3-O3P) binding mode, the ladder [Scheme 4(d)] and sheet
polymer [Scheme 4(e)] could be obtained.
The compounds 1 and 4 can dissolve in CHCl3 and DMSO,
respectively. However, the compounds 2, 3 and 5 could hardly
dissolve in any organic solvent. Therefore, 1H, 13C and 119Sn
NMR data of the compounds 1 and 4 were measured and
1
discussed. The H NMR spectrum of 1 displays signals at 0.59–
0.71 ppm for the methyl groups (CH3 of n-Bu), 0.87–1.40 ppm
for the methylene groups (-CH2 of n-Bu), 1.53–1.73 ppm for the
methyl groups (-OCH3), and 3.48 ppm for the methyl groups
(CH3OH). Other signals at 7.06–7.90 ppm can be attributed to
the phenyl groups. The 13C NMR spectrum of 1 shows a signal
at 13.57 ppm for the methyl groups (CH3 of n-Bu), and 25.92–
27.04 ppm for the methylene groups (-CH2 of n-Bu). Other signals
at 126.97–131.22 ppm may result from the phenyl groups. The 119Sn
NMR signals of 1 occurred at -507.9, -515.2 and -545.0 ppm,
respectively. The high negative chemical shifts observed in the 119Sn
NMR indicate the presence of the CO5 coordination environment
around tin.7d The 1H NMR spectrum of 4 displays signals at 0.82
and 2.31 ppm for the methyl groups (CH3 of n-Bu and CH3 of
p-Me-Ar), 1.26 and 1.56 ppm for the methylene groups (-CH2 of
n-Bu). The signals of the phenyl groups were observed at 7.14,
7.52, 8.09 and 8.46 ppm. The 13C NMR spectrum of 4 shows two
signals at 14.16 and 21.46 ppm for the methyl groups (CH3 of
n-Bu and CH3 of p-Me-Ar), two signals (26.80 and 27.67 ppm) for
the methylene groups (-CH2 of n-Bu), and other signals (124.86,
126.15, 128.81, 132.34, 138.81, 141.01, 145.43 and 150.79 ppm)
for the phenyl groups. The 119Sn NMR signal of 4 appeared at
-294.44 ppm, which is similar to that of reported diorganotin
phosphonates.9a
Conclusion
In conclusion, five organotin phosphonates and arsonates {[(n-
BuSn)3(MeO)3O]2(O3PPh)4}·MeOH 1, [n-Bu2SnO3PPh]n 2, [n-
Bu2Sn(4-OH-3-NO2-C6H3AsO3)]n 3, [n-Bu2Sn(4-Me-C6H4SO3)(4-
NO2-C6H4AsO3H)]n 4 and [(Ph3Sn)4(4-NO2-C6H4AsO3)2·H2O]n
5 have been successfully isolated. Compound 1 represents the
hexanuclear monoorganooxotin phosphonate cage. The crystal
structures of 2 and 3 feature diorganotin ladders. Compound
4 represents the diorganotin arsonate double chain which con-
tains both sulfonate and arsonate ligands. Compound 5 shows
the triorganotin arsonate single chain structure. From the re-
sults, we can conclude that utilizing the n-Bu2Sn(PhCO2)2 and
[n-Bu2(PrO)Sn]2O as starting precursors are a very efficient
Scheme 4 Possible structures for complexes R2Sn[R’EO3] (E = P or As).
Apparently, the ladder structure of 2 and 3 are consistent with
that of Scheme 4(d). It should be pointed out that the diorgan-
otin phosphonate and arsonate ladders were firstly confirmed
through the single-crystal X-ray diffraction method. Therefore,
compounds 2 and 3 are the first examples of the diorganotin
ladder surmised by Cunningham et al. The diorganotin arsonate
double chain of 4 comprises alternate eight-membered rings being
formed by the hydrogenarsonate and sulfonate ligands. However,
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method for the syntheses of novel diorganotin compounds.
Further study of access to new organotin phosphonate and
arsonate through the reactions of the organotin precursors is
underway in our laboratory.
1312 (w), 1252 (m), 1140 (w), 1102 (m), 1066 (w), 1044 (w), 897
(m), 874 (s), 828 (s), 545 (m), 507 (m), 450 (m), 423 (m).
Synthesis of compound 4
A mixture of [n-Bu2(PrO)Sn]2O (0.300 g, 0.5 mmol), 4-NO2-
C6H4AsO3H2 (0.124 g, 0.5 mmol) and 4-Me-C6H4SO3H (0.088 g,
0.5 mmol) was stirred in a chloroform (5 ml)/methanol (15 ml)
for 6 h and filtered. The filtrate was left undisturbed to con-
centrate slowly by evaporation. After 1 week, colorless crystals
of compound 4 were collected. Yield 0.052 g [16% based on [n-
Bu2(PrO)Sn]2O. Anal. Calcd for C21H30AsNO8SSn (Mr = 649.92):
C, 38.86; H, 5.96; N, 4.50. Found: C, 38.62; H, 4.74; N, 4.64.1H
NMR (ppm): 0.82 (m, 12H, CH3 of n-Bu), 1.26 and 1.56 (m,
24H, CH2 of n-Bu), 2.31 (s, 6H, CH3 of p-Me-Ar), 7.14, 7.52, 8.09
and 8.46 (s, 16H, Ph); 13C NMR (ppm): 14.16 and 21.46 (CH3
of n-Bu and CH3 of p-Me-Ar), 26.80, and 27.67 (CH2 of n-Bu),
124.86, 126.15, 128.81, 132.34, 138.81, 141.01, 145.43 and 150.79
(Ph);119Sn NMR (ppm): -294.4. IR (cm-1): 3830 (w), 3725 (m),
3410 (m), 3100 (m), 2964 (m), 1652 (w), 1608 (w), 1533 (s), 1347
(m), 1208 (m), 1150 (m), 1095 (w), 1028 (m), 940 (m), 843 (s), 740
(w), 568 (w), 506 (w), 447 (m), 420 (m).
Experimental
General procedures
[n-Bu2(PrO)Sn]2O and n-Bu2Sn(PhCO2)2 were prepared by lit-
erature methods.9a,10 C6H5PO3H2, 4-OH-3-NO2-C6H3AsO3H2, 4-
NO2-C6H4AsO3H2, 4-Me-C6H4SO3H and reagents were pur-
chased from commercial sources. The C, H, and N elemental anal-
ysis was conducted on a Perkin-Elmer 240C elemental analyzer.
The FT-IR spectra were recorded from KBr pellets in the range
4000–400 cm-1 on a Mattson Alpha-Centauri spectrometer. H,
1
13C and 119Sn NMR spectra of compounds 1 and 4 were recorded
on a Mercury Plus-400 NMR spectrometer, and chemical shifts
were given relative to Me4Si and Me4Sn.
Synthesis of compound 1
A mixture of n-BuSn(O)OH (0.104 g, 0.5 mmol) and PhPO3H2
(0.08 g, 0.5 mmol) in methanol (10 ml) was heated in a 15 ml Teflon-
lined autoclave at 140 ◦C for 3 days. When the mixture was cooled
to room temperature, the resulting colorless crystals of compound
1 were collected and washed with methanol. Yield 0.347 g [36%
based on n-BuSn(O)OH). Anal. Calcd for C55H96O21P4Sn6 (Mr =
1929.34): C, 34.24; H, 5.02. Found: C, 34.41; H, 5.34.1H NMR
(ppm): 0.59–0.71 (m, 18H, CH3 of n-Bu), 0.87–1.73 (m, 36H,
CH2 of n-Bu), 1.53–1.73 (m, 18H, OCH3), 3.48 (m, 3H, CH3O),
7.06–7.90 (m, 20H, Ph); 13C NMR (ppm): 13.57 (CH3 of n-Bu),
25.92–27.04 (CH2 of n-Bu), 126.97–131.22 (Ph);119Sn NMR (ppm):
-507.9, -515.2 and -545.0. IR (cm-1): 3737 (w), 3617 (w), 3588 (w),
3046 (w), 2921 (w), 2829 (w), 1519 (w), 1426 (m), 1382 (w), 1096
(m), 1026 (m), 862 (s), 814 (m), 723 (m), 690 (m), 509 (m), 437 (m).
Synthesis of compound 5
The 4-NO2-C6H4AsO3H2 (0.124 g, 0.5 mmol) and EtONa (0.068 g,
1 mmol) were added to the solution of dry ethanol (30 ml) in
a standard Schlenk technique, and the mixture was stirred for
10 min. Triphenyltin(IV) chloride (0.386 g, 1 mmol) was then added
to the mixture, and the reaction was refluxed for 6 h. The solution
was filtered and the solvent of the filtrate was left undisturbed to
concentrate slowly by evaporation. After 1 week, colorless crystals
of compounds 5 were collected. Yield 0.109 g [23% based on
Ph3SnCl]. Anal. Calcd for C84H70As2N2O11Sn4 (Mr = 1908.02):
C, 52.87; H, 3.70; N, 1.47. Found: C, 53.32; H, 3.73; N, 1.64. IR
(cm-1): 3740 (w), 3649 (w), 3622 (w), 3414 (m), 3101 (w), 2927 (w),
1644 (w), 1612 (w), 1520 (s), 1482 (w), 1428 (w), 1351 (m), 1088
(m), 1037 (m), 883 (s), 848 (s), 722 (m), 678 (m), 568 (m), 445 (s),
418 (s).
Synthesis of compound 2
A mixture of n-Bu2Sn(PhCO2)2 (0.210 g, 0.05 mmol) and PhPO3H2
(0.08 g, 0.5 mmol) was stirred in a chloroform (5 ml)/methanol
(15 ml) for 6 h and filtered. The filtrated was left undisturbed to
concentrate slowly by evaporation. After 1 week, colorless crystals
of compound 2 were collected. Yield 0.135 g [23% based on n-
Bu2Sn(PhCO2)2. Anal. Calcd for C42H69O9P3Sn3 (Mr = 1166.95):
C, 43.23; H, 5.96. Found: C, 43.41; H, 5.74. IR (cm-1): 3748 (w),
3633 (w), 3047 (m), 2958 (w), 2932 (w), 1687 (w), 1586 (w), 1547
(m), 1494 (m), 1451 (w), 1121 (s), 1042 (s), 810 (m), 748 (m), 696
(m), 544 (m), 450 (m), 423 (m).
X-ray crystallography
Single-crystal X-ray diffraction data for compound 3 was
recorded on a Bruker Apex CCD diffractometer with graphite-
˚
monochromated Mo-Ka radiation (l
=
0.71073 A) at
293 K. Diffraction data for other compounds were collected on
a Rigaku RAXIS-RAPID single-crystal diffractometer with Mo-
˚
Ka radiation (l = 0.71073 A) at 293 K. Absorption corrections
were applied using the multi-scan technique.11 All the structures
were solved by the Direct Method of SHELXS-9712 and refined
by full-matrix least-squares techniques using the SHELXL-97
program13 within WINGX.14 The detailed crystallographic data
and structure refinement parameters for the compounds are
summarized in Table 1.
Synthesis of compound 3
A mixture of [n-Bu2(PrO)Sn]2O (0.150 g, 0.25 mmol) and 4-OH-3-
NO2-C6H3AsO3H2 (0.132 g, 0.5 mmol) was stirred in a chloroform
(5 ml)/methanol (15 ml) for 6 h and filtered. The filtrated was left
undisturbed to concentrate slowly by evaporation. After 1 week,
colorless crystals of compound 3 were collected. Yield 0.027 g
[11% based on [n-Bu2(PrO)Sn]2O. Anal. Calcd for C14H22AsNO6Sn
(Mr = 493.94): C, 34.04; H, 4.49. Found: C, 34.21; H, 4.34. IR
(cm-1): 3240 (w), 1612 (s), 1575 (w), 1530 (m), 1489 (m), 1432 (w),
Acknowledgements
We thank the Program for Changjiang Scholars and Inno-
vative Research Teams in Chinese University, China Post-
doctoral Science Foundation, the Postdoctoral Foundation of
1574 | Dalton Trans., 2010, 39, 1568–1575
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Northeast Normal University (NENU), the Training Fund of
NENU’s Scientific Innovation Project and the Analysis and
Testing Foundation of NENU for support.
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