Synthesis and structure of an ether-bridged double ladder compound: Potential in host-guest chemistry

Article abstract of DOI:10.1016/j.jorganchem.2003.08.029

The synthesis of the first example of an organotin double ladder (6) containing a functional group within the spacer is reported. In the solid state, compound 6 shows an interlaminar cavity whose size and shape suggest the possibility of host-guest chemistry. ¹¹⁹ Sn-NMR and ESMS show that compound 6 undergoes extensive dissociation in solution. ESMS of compound 6 to which have been added Li⁺, Na⁺, Mg²⁺ or Cu²⁺ show only minimal interaction.

Full text of DOI:10.1016/j.jorganchem.2003.08.029

Journal of Organometallic Chemistry 688 (2003) 56Á61
/
www.elsevier.com/locate/jorganchem
Synthesis and structure of an ether-bridged double ladder compound:
potential in hostÁguest chemistry
/
Jens Beckmann a, Dainis Dakternieks a,*, Andrew Duthie a, Fong Sheen Kuan a,
Edward R.T. Tiekink b,*
a Centre for Chiral and Molecular Technologies, Deakin University, Geelong, Vic. 3217, Australia
b Department of Chemistry, National University of Singapore, 117543 Singapore, Singapore
Received 2 June 2003; received in revised form 19 August 2003; accepted 27 August 2003
Abstract
The synthesis of the first example of an organotin double ladder (6) containing a functional group within the spacer is reported. In
the solid state, compound 6 shows an interlaminar cavity whose size and shape suggest the possibility of hostÁguest chemistry.
/
119Sn-NMR and ESMS show that compound 6 undergoes extensive dissociation in solution. ESMS of compound 6 to which have
been added Liꢀ, Naꢀ, Mg2ꢀ or Cu2ꢀ show only minimal interaction.
# 2003 Elsevier B.V. All rights reserved.
Keywords: Organotin double ladder; HostÁguest chemistry; Ether group; Tetraorganodistannoxane; X-ray
/
1. Introduction
vestigations on its potential for hostÁguest applications
/
with a number of metal cations using electrospray mass
spectrometry (ESMS).
Recently, there has been considerable interest in the
synthesis of self-assembled organotinÁoxo clusters [1].
/
In preceding work, we and others have utilized spacer-
bridged organotin precursors as building blocks for the
preparation of a variety of organotinÁoxo clusters
having double [2] and triple ladder [3] structures that
feature layered dimeric tetraorganodistannoxanes with
/
2. Discussion
The transition metal-catalyzed double hydrostannyla-
Sn4O2X2Y2 (X, Yꢁ
units (Chart 1). The spacing between these layers is
adjustable by the choice of the organic spacers, Z, e.g. Á
(CH2)n Á (nꢁ1Á12), p- or m-CH2SiMe2C6H4SiMe2
CH2Á, p- or m-(CH2)2C6H4(CH2)2 and consequently,
/F, Cl, Br, OH, O2CR) structural
tion of allyl ether, (CH2Ä
/
CHCH2)2O, with Ph3SnH
ether,
provided 1,7-bis(triphenylstannyl)dipropyl
[Ph3Sn(CH2)3]2O (1). Subsequent reaction of 1 with
two equivalents of iodine gave the corresponding 1,7-
/
/
/
/
/
bis(iododiphenylstannyl)dipropyl
ether,
[IPh2Sn
well-defined cavities can be created [2]. It was hypothe-
sized that if ether or amine groups were incorporated
into the organic spacers it might be possible to bind
metal cations in these cavities in a similar manner to
crown ethers and cryptands [4].
(CH2)3]2O (2). Compound 2 was reacted with two
equivalents of trimethylsilylmethylmagnesium chloride,
Me3SiCH2MgCl, to produce 1,7-bis(trimethylsilyl-
methyldiphenylstannyl)dipropyl ether, [(Me3SiCH2)Ph2
Sn(CH2)3]2O (3), which was then converted with conc.
hydrochloric acid into 1,7-bis(trimethylsilylmethyldi-
We report now the synthesis and structure of the first
ether-functionalised double ladder compound and in-
chlorostannyl)dipropyl
ether,
[(Me3SiCH2)Cl2Sn
(CH2)3]2O (4). A portion of 4 was hydrolyzed to the
presumed polymeric 1,7-bis(trimethylsilylmethyloxos-
tannyl)dipropyl ether, {[(Me3SiCH2)(O)Sn(CH2)3]2O}n
(5) (Scheme 1).
* Corresponding authors.
E-mail addresses: dainis@deakin.edu.au (D. Dakternieks),
chmtert@nus.edu.sg (E.R.T. Tiekink).
0022-328X/03/$ - see front matter # 2003 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2003.08.029

J. Beckmann et al. / Journal of Organometallic Chemistry 688 (2003) 56Á
/61
57
Chart 1.
Fig. 1. Molecular structure and crystallographic numbering scheme
employed for compound 6. The Sn2ÁC4 bond is superimposed upon
the Sn1 atom, which in turn obscures the C15 atom, and the C18 atom
/
obscures the C17 atom.
The molecular structure of 6 is shown in Fig. 1 and
selected geometric parameters are given in Table 1. The
octanuclear molecule features two [(RSnCl)2O]2 distan-
noxane units defining the faces of a rectangular box. The
faces are connected so that centrosymmetrically related
Sn atoms (i.e. Sn1 and Sn2i & Sn3 and Sn4i for
Scheme 1.
Compounds 1Á
/
5 were obtained in high yields as
colorless oils (1, 3, 4) or solids (2, 5) and were
characterized by multinuclear NMR spectroscopy and
elemental analysis (experimental section).
symmetry operation iꢁ
/
ꢂ
/
x, ꢂ
/
y, ꢂz) are linked by
/
The reaction of [(Me3SiCH2)Cl2Sn(CH2)3]2O (4) with
{[(Me3SiCH2)(O)Sn(CH2)3]2O}n (5), resulted in the
formation of the ether-bridged double ladder compound
{{[(Me3SiCH2)(Cl)Sn(CH2)3]2O}O}4 (6), which was ob-
tained as a colorless high-melting solid in good yield
(Eq. (1)).
Table 1
˚
Selected bond lengths (A) and bond angles (8) for 6
Bond lengths
Sn1Á
Sn1Á
Sn1Á
Sn2Á
Sn2Á
Sn3Á
Sn3Á
Sn3Á
Sn4Á
Sn4Á
/
Cl1
2.699(2)
2.142(4)
2.098(7)
2.126(5)
2.116(7)
2.761(3)
2.019(5)
2.113(9)
2.455(2)
2.123(8)
Sn1Á
Sn1Á
Sn2Á
Sn2Á
Sn2Á
Sn3Á
Sn3Á
Sn4Á
Sn4Á
Sn4Á
/
O1
C1
2.048(5)
2.109(8)
2.724(2)
2.048(5)
2.104(8)
2.456(3)
2.113(9)
2.745(2)
2.007(4)
2.124(7)
/O2
/
/C13
/
Cl2
O2
/O1
/
/C4
/
C17
Cl3
C7
/Cl1
/
/O1
/
/
C21
Cl4
C10
/
Cl2
O2
/
/
/
/
C25
Bond angles
Cl1Á
Cl1Á
Sn1Á
Sn1Á
Sn2Á
Sn1Á
/
Sn1Á
Sn3Á
Cl1Á
O1Á
O1Á
O2Á
/
O2
151.35(13)
163.13(9)
81.91(6)
105.4(2)
128.5(3)
128.0(2)
Cl2Á
Cl2Á
Sn2Á
Sn1Á
Sn1Á
Sn2Á
/
Sn2Á
Sn4Á
Cl2Á
O1Á
O2Á
O2Á
/
O1
151.10(15)
164.66(7)
81.26(5)
123.3(2)
104.8(2)
122.8(2)
/
/Cl3
/
/
Cl4
Sn4
/
/Sn3
/
/
/
/
Sn2
Sn3
Sn4
/
/
Sn3
Sn2
Sn4
/
/
/
/
/
/
/
/
ð1Þ

58
J. Beckmann et al. / Journal of Organometallic Chemistry 688 (2003) 56Á61
/
the ‘ether’ spacers. The Sn atoms exist in distorted
trigonal bipyramidal geometries defined by a C2ClO2
donor set for the endocyclic Sn1 and Sn2 atoms and by a
C2Cl2O donor set for the exocyclic Sn3 and Sn4 atoms.
The axial positions are occupied by Cl and O atoms for
the endocyclic Sn atoms and Cl atoms for the exocyclic
Sn centers. The terminal SnÁCl bond distances formed
/
by the exocyclic Sn atoms are significantly shorter than
those involving the Cl1 and Cl2 atoms owing to the
latter occupying bridging positions in the molecule.
There is evidence for some minor buckling within the
distannoxane unit so that the dihedral angles between
the planes through Sn1/Sn3/Cl1/O1, Sn1/Sn2/O1/O2,
and Sn2/Sn4/Cl2/O2 are 2.86(17), 7.23(12) and
4.47(17)8, respectively. Owing to the symmetry in the
molecule, the dihedral angle between the two distannox-
ane faces is 08. The average separation calculated
Fig. 2. 119Sn-NMR spectrum (100.7 MHz) of 6 in CDCl3.
˚
between the two Sn4 planes is 10.3 A with values
˚
ranging from 10.14 to 10.38 A. From Fig. 1 it is evident
spectroscopy. Thus, the signals at d ꢂ
/
84.0 and ꢂ133.8
/
that the ether-O atoms are directed towards the middle
of the polygon, thereby demonstrating potential as a
host for the coordination of metal ions. The Oꢀ ꢀ ꢀO
appear to be related and are tentatively assigned to
exocyclic and endocyclic tin sites of {{[(Me3-
SiCH2)(Cl)Sn(CH2)3]2O}O}4 (6). Additionally, there
also appears to be a correlation between the signals at
separations within the cavity of the molecule are 2ꢃ
/
˚
4.80 A and therefore indicates that the
separations between the diagonally opposite O atoms
4.04 and 2ꢃ
/
d ꢂ
/
103.6 and ꢂ123.9, however no assignment of these
/
or the remaining signals was made.
The ESMS spectrum (cone voltage 20 V) of 6 in
˚
are non-symmetric at 4.67 and 7.54 A. Assuming an
˚
atomic radius of 0.76 A or a van der Waals radius of
˚
1.40 A for the ether-O atom, and that the O4 rectangle is
robust, the ‘hole-size’ of the cavity along the shortest
MeCN reveals positively charged species at m/zꢁ
1125.0 (34%) and m/zꢁ1143.0 (50%), which were
confirmed by their isotropic patterns as belonging to
[1/2Mꢂ3Clꢀ 2Clꢀ
2OH]ꢀ and [1/2Mꢂ OH]ꢀ, respec-
tively. In the negative mode, the same sample shows
dominate peaks at m/zꢁ634.9 (20%) and m/zꢁ688.9
Oꢀ
/
/
˚
diagonal would be approximately 3.1 A or 1.9 A,
˚
/
/
/
/
respectively. Along the other diagonal, the ‘hole-size’ is
˚
significantly larger at approximately 6.0 A or 4.7 A,
˚
/
/
(100%) indicative for [1/4Mꢀ
/
Cl]ꢂ and [1/4Mꢂ
/
/
respectively. Mitigating factors against hostÁguest
/
3Cl]ꢂ, respectively. The observation of mass clusters
chemistry could be the (i) non-symmetric shape of the
cavity, (ii) the large size of the cavity that would not
allow for optimal bonding interactions, and (iii) the
presence, in very close proximity, above and below the
O4 plane, of methylene groups that can be conceived as
providing steric hindrance.
The ether-bridged double ladder compound {{[(Me3-
SiCH2)(Cl)Sn(CH2)3]2O}O}4 (6), is readily soluble in
most common organic solvents. The 119Sn-NMR spec-
trum (CDCl3) of an analytically pure, crystalline sample
at about half or a quarter of the mass expected for the
double
ladder
compound
{{[(Me3-
SiCH2)(Cl)Sn(CH2)3]2O}O}4 (6) and the number of
signals in the 119Sn-NMR spectrum suggests that
compound 6 is involved in extensive equilibria with
tetra- and di-nuclear organotin complexes in solution
(Eq. (2)). Although, the analogous n-methylene-spacer
bridged
double
ladder
compounds
{{[RSn(Cl)]2(CH2)n}O}4 (nꢁ
/
5Á8, 10, 12) are also
/
of 6 is complex and shows 19 signals at d ꢂ
(integral 1.4%), ꢂ84.0 (integral 4.5%), ꢂ93.4 (integral
14.0%), ꢂ96.0 (integral 5.0%), ꢂ100.1 (integral 1.0%),
103.6 (integral 8.0%), ꢂ123.9 (integral 8.1%), ꢂ
127.6 (integral 5.8%), ꢂ132.0 (integral 2.0%), ꢂ133.0
(integral 2.0%), ꢂ133.8 (integral 5.0%), ꢂ136.0 (inte-
gral 17.0%), ꢂ137.8 (integral 1.4%), ꢂ148.7 (integral
2.8%), 150.2 (integral 11.0%), 153.5 (integral
0.5%), ꢂ154.5 (integral 0.5%), ꢂ155.5 (integral 0.5%)
and ꢂ175.5 (integral 0.5%) (Fig. 2). Attempts were
/
80.0
known to be in equilibrium with their respective dimers
in solution [2], the dissociation of 6 into di-nuclear
complexes was somewhat unexpected and is tentatively
attributed to intramolecular stabilization by the ether
group, which would maintain a pentacoordinate tin
environment as depicted in Eq. (2). This hypothesis is
supported by the recently reported solution and solid-
state structures of diorganotin dichlorides R2SnCl2 and
PhRSnCl2 having intramolecularly coordinating (3-(2-
/
/
/
/
ꢂ
/
/
/
/
/
/
/
/
/
ꢂ
/
ꢂ
/
/
/
/
methoxy)ethoxy)propyl substituents
CH2CH2CH2OCH2CH2OCH3) [5].
(Rꢁ
/
made to establish the connectivity of these signals using
variable temperature 2D INADEQUATE 119Sn-NMR

J. Beckmann et al. / Journal of Organometallic Chemistry 688 (2003) 56Á
/61
59
enced to SiMe4 (1H, 13C) and SnMe4 (119Sn). Uncor-
rected melting points were determined on a Reichert hot
stage. Microanalysis was performed by CMAS, Bel-
mont, Australia. The ESMS spectrum was obtained with
a Platform II single quadrupole mass spectrometer
(Micromass, Altrincham, UK) using an acetonitrile
mobile phase. Acetonitrile solutions (0.1 mM) were
injected directly into the spectrometer via a Rheodyne
injector equipped with a 50 ml loop. A Harvard 22
syringe pump delivered the solutions to the vaporisation
nozzle of the electrospray ion source at a flow rate of 10
ml minꢂ1. Nitrogen was used as both a drying gas and
for nebulisation with flow rates of approximately 200
and 20 ml minꢂ1, respectively. Pressure in the mass
analyser region was usually about 4ꢃ
10ꢂ5 mbar.
/
Typically ten signal-averaged spectra were collected.
The isotope pattern of the experimentally obtained mass
clusters was consistent with expected mass clusters based
on the natural abundance of the elements involved.
ð2Þ
{{[(Me3-
The
feasibility
of
SiCH2)(Cl)Sn(CH2)3]2O}O}4 (6) forming hostÁguest
/
complexes with the metal cations Liꢀ, Naꢀ, Mg2ꢀ
3.1. Synthesis of [Ph3Sn(CH2)3]2O (1)
and Cu2ꢀ was investigated using ESMS spectrometry.
A solution of Ph3SnH (58.2 g, 166 mmol) in toluene
(80 ml) was added slowly over a 3 h period to a solution
of allyl ether (6.51 g, 66.3 mmol) in toluene (40 ml) and
Pd(OH)2/C (20 mg) at 80 8C. The reaction mixture was
stirred at 80 8C for 3 d and the solvent removed in vacuo
to afford a slightly yellow residue. To the residue,
chloroform (80 ml), H2O2 (40 ml) and a solution of
KF (5.00 g) in water (40 ml) were added and stirred at
room temperature (r.t.) for 6 h, after which the solvent
was removed in vacuo. The residue was extracted with
Solutions of 6 in MeCN (cꢁ
of the metal chlorides in H2O (cꢁ
and ESMS spectra measured in the positive mode at
various cone voltages. (i) Naꢀ: Low intensity peaks
/
0.1 mM) and solutions
0.1 mM) were mixed
/
were observed at m/zꢁ
2476.8 (2%) and m/zꢁ
were assigned to the complexes [Mꢀ
NaCl]ꢀ and [Mꢀ 2NaCl]ꢀ, respectively. (ii) Liꢀ:
Naꢀ
At 200 V, the ESMS spectrum showed peaks at m/zꢁ
605.0 (rel. intensity 16%), m/zꢁ646.0 (rel. intensity
15%) and m/zꢁ1204.9 (rel. intensity 10%), which were
assigned to the complexes [1/4Mꢀ
Li]ꢀ, for [1/4Mꢀ
Liꢀ
MeCN]ꢀ and [1/2MꢀLi]ꢀ, respectively. No evi-
/
2418.8 (rel. intensity 1%), m/zꢁ
2534.7 (rel. intensity 2%), which
Na]ꢀ, [Mꢀ
Naꢀ
/
/
/
/
/
/
/
/
/
diethyl ether (3ꢃ80 ml), dried (Na2SO4) and the solvent
/
/
was removed in vacuo to yield a greenish residue. The
volatile by-products were removed using a Kugelrohr
apparatus (230 8C, 0.01 mmHg). Further purification of
the crude product was achieved by column chromato-
/
/
/
/
dence for complex formation between 6 and the divalent
metal cations Mg2ꢀ and Cu2ꢀ was observed.
It appears that compound 6 has only a limited
graphy (silica gel 60, 70Á230 mesh) using hexane as the
/
eluent. The solvent was removed in vacuo to give 1 as a
colorless oil (46.5 g, 70%).
1H-NMR: d 0.85 (t, 4H), 1.23 (m, 4H), 3.25 (t, 4H),
potential to form hostÁguest complexes with metal
/
cations. This limitation could arise from the geometric
constraints associated with the interlaminar cavity. It is
more likely, however, that the entropy gained from
dissociation of the double ladder into dimers and
monomers outweighs the thermodynamic contribution
7.25Á
(1J(13CÁ117/119
117/119Sn)ꢁ21 Hz), 74.02 (CH2, J(13CÁ117/119
Hz), 128.92, 129.27, 137.50 (2J(13Co Á117/119
Hz), 139.58 Sn)ꢁ467/490
(1J(13Ci Á117/119
119Sn{1H}-NMR: d ꢂ98.4 (1J(119SnÁ13
C)ꢁ487 Hz).
/
7.64 (m, 30H; Ph). 13C{1H}-NMR:
d
7.77
/
Sn)ꢁ
/
382/401 Hz), 26.97 (2J(13CÁ
/
3
/
/
Sn)ꢁ
Sn)ꢁ
/
64
35
/
/
gained by hostÁguest adduct formation as discussed
/
/
/
Hz).
above and/or the kinetic lability of the cluster in
solution.
/
/
/
Anal. Calc. for C42H42OSn2 (800.27): C, 63.2; H, 5.3;
Found: C, 63.6; H, 5.1%.
3. Experimental
3.2. Synthesis of [IPh2Sn(CH2)3]2O (2)
All solvents were dried and purified by standard
procedures. NMR spectra were recorded in CDCl3
solution using a Varian 300 Unity Plus (1H, 13C) and
a JEOL-GX 270 spectrometer (119Sn) and were refer-
A solution of iodine (9.96 g, 39.2 mmol) in dichlor-
omethane (1.0 l) was added to a solution of 1 (15.7 g,
19.6 mmol) in dichloromethane (100 ml) at 0 8C over 10
h. Removal of the solvent and by-product in vacuo and

60
J. Beckmann et al. / Journal of Organometallic Chemistry 688 (2003) 56Á61
/
crystallization from chloroformÁ
white crystalline solid (16.8 g, 95%). m.p. 98Á
1H-NMR: d 1.58 (t, 4H), 1.82 (m, 4H), 3.26 (t, 4H),
7.26Á
7.63 (m, 20H; Ph). 13C{1H}-NMR: d 14.41
(1J(13CÁ117/119 420/439 Hz), 25.80 (2J(13Cm Á
Sn)ꢁ
117/119Sn)ꢁ27 Hz), 72.10 (3J(13Cp Á117/119
Sn)ꢁ63 Hz),
128.54, 129.56 (2J(13Cm Á117/119
Sn)ꢁ13 Hz), 135.73
(2J(13Co Á117/119 (1J(13Ci Á
Sn)ꢁ47 Hz), 137.14
117/119Sn)ꢁ531/554 Hz). 119Sn{1H}-NMR: d ꢂ
85.8.
/
hexane afforded 2 as a
(2J(13CÁ117/119
/
Sn)ꢁ
/
36 Hz), 71.06 (3J(13CÁ117/119
/
Sn)ꢁ
/
/
100 8C.
73 Hz). 119Sn{1H}-NMR: d 79.1. Anal. Calc. for
C14H34Cl2OSi2Sn2 (653.83): C, 25.7; H, 5.2; Found: C,
25.7; H, 5.6%.
/
/
/
/
/
/
/
3.5. Synthesis of {[(Me3SiCH2)(O)Sn(CH2)3]2O}n
/
/
(5)
/
/
/
/
/
A solution of KOH (0.24 g, 4.28 mmol) in water (50
ml) was added to a solution of 4 (0.70 g, 1.07 mmol) in
toluene (50 ml) and the mixture stirred at 100 8C for 1 d.
The white precipitate that formed was collected by
filtration. The collected precipitate was then stirred
with water (400 ml), filtered and further dried by heating
at 80 8C (0.01 mm Hg) for 2 d to give 5 as a white solid
(0.50 g, 86%). m.p.ꢀ300 8C (decomp.).
Anal. Calc. for C14H34O3Si2Sn2 (544.01): C, 30.9; H,
6.3; Found: C, 30.5; H, 6.2%.
Anal. Calc. for C30H32I2OSn2 (899.86): C, 40.0; H, 3.6;
Found: C, 40.1; H, 3.5%.
3.3. Synthesis of [(Me3SiCH2)Ph2Sn(CH2)3]2O (3)
A solution of 2 (10.4 g, 11.6 mmol) in THF (100 ml)
was added to a solution of Me3SiCH2MgCl [prepared
from magnesium (2.47 g, 102 mmol) and Me3SiCH2Cl
(3.12 g, 25.4 mmol) in THF (150 ml)] and the mixture
stirred at reflux for 2 d. The reaction was quenched by
the addition of saturated ammonium chloride at 25 8C.
The organic layer was separated, and the aqueous layer
/
3.6. Synthesis of
{{[(Me3SiCH2)(Cl)Sn(CH2)3]2O}O}4 (6)
was extracted with diethyl ether (3ꢃ100 ml). The
/
combined organic extracts were dried (Na2SO4) and
the solvent was removed in vacuo. The residue was
A solution of 4 (90.0 mg, 0.13 mmol) in toluene (2 ml)
was added to a suspension of 5 (70.0 mg, 0.13 mmol) in
toluene (2 ml) and stirred at 100 8C for 24 h. Removal of
the solvent in vacuo and crystallization from
purified by column chromatography (silica gel 60, 70Á
/
230 mesh) using hexane. Removal of the solvent in
vacuo yielded 3 as a colorless oil (7.57 g, 80%).
1H-NMR: d 0.18 (s, 18H, SiMe3), 0.89 (s, 4H, SiCH2),
chloroformÁ
crystals (170 mg, 92%). m.p. 268Á
1H-NMR: d 0.13 (s, 36H, Me3Si), 0.72Á
/
hexane (30:70) afforded 6 as a colorless
/
270 8C.
1.29 (s, 4H), 1.85 (s, 4H, SnCH2), 3.30 (s, 4H), 7.27 (m,
/1.28 (m, 16H,
1
20H). 13C{1H}-NMR: d ꢂ
/
9.97 (s, J(13CÁ117/119
/
Sn)ꢁ
/
SiCH2), 1.59Á
/
1.89 (m, 16H), 2.13Á
/
2.29 (m, 16H), 3.47Á
/
3
245/257 Hz; SiCH2), ꢂ
Hz, Si)ꢁ51
1J(13CÁ29
(1J(13CÁ117/119
Sn)ꢁ363/380
(2J(13CÁ117/119 19 Hz), 69.32 (3J(13CÁ117/119
Sn)ꢁ
72 Hz), 123.71, 123.97, 132.15 (2J(13Co Á117/119
Hz), 136.22 Sn)ꢁ440/461
(1J(13Ci Á117/119
119Sn{1H}-NMR: d ꢂ56.5 (1J(119SnÁ13
C)ꢁ463 Hz).
/
2.92 (s, J(13CÁ117/119
Hz; Me3Si),
Hz),
/
Sn)ꢁ16
/
3.62 (m, 16H). 119Sn{1H}-NMR: refer to text and Fig. 2.
Anal. Calc. for C56H136Cl8O8Si8Sn8 (2395.68): C, 28.1;
H, 5.7; Found: C, 28.2; H, 5.5%.
/
/
3.22
22.11
/
/
/
/
/
Sn)ꢁ
Sn)ꢁ39
Hz).
/
/
/
/
/
4. Crystallography
/
/
/
Anal. Calc. for C38H54OSi2Sn2 (820.49): C, 55.6; H, 6.6;
Found: C, 55.4; H, 6.7%.
Slow evaporation of a chloroformÁ
solution of 6 gave crystals suitable for X-ray analysis.
Data were collected for a colorless crystal of 6, 0.12ꢃ
0.21ꢃ0.34, at 183 K employing graphite monochroma-
tized MoÁ
AXS SMART CCD diffractometer.
Crystal data for 6: C56H136Cl8O8Si8Sn8, Mꢁ
monoclinic, space group C2/c, aꢁ38.014(1), bꢁ
105.805(9)8, Vꢁ
1.592 g cmꢂ3, mꢁ2.312 mmꢂ1
4736, 14484 unique data, 11203 data with
2.0s(I), Rꢁ0.079, Rw (all data)ꢁ0.207, rꢁ2.34
/
hexane (30:70)
/
3.4. Synthesis of [(Me3SiCH2)Cl2Sn(CH2)3]2O (4)
/
˚
Ka radiation, lꢁ0.71069 A, on a Bruker
/
/
To a solution of 3 (6.00 g, 7.31 mmol) in chloroform
(100 ml) was added excess concentrated HCl (200 ml,
32%). The reaction mixture was stirred and maintained
at 70 8C for 1 d. The organic layer was separated and the
/2395.49,
/
/
˚
12.438(3), cꢁ
/
21.972(5) A, bꢁ
9996(4) A , Dx ꢁ
F(000)ꢁ
I ]
/
/
3
˚
aqueous layer extracted with chloroform (3ꢃ
/100 ml).
/
/
,
The combined organic extracts were dried (CaCl2) and
the solvent removed in vacuo to afford 4 as a brown oil
(3.35 g, 70%) of sufficient purity for further use.
1H-NMR: d 0.15 (s, 18H, Me3Si), 0.83 (s, 4H,
/
/
/
/
/
ꢂ3
˚
e A
(near Sn).
The structure was solved by heavy-atom methods [6]
and refined by a full-matrix least-squares procedure
based on F2 [6b]. Non-hydrogen atoms were refined
anisotropically, hydrogen atoms were included in the
model in the riding model approximation and a weight-
SiCH2), 1.69 (t, 4H), 2.08Á
/
2.10 (m, 4H), 3.57 (t, 4H).
13C{1H}-NMR: d 1.02 (s, 3J(13CÁ117/119
/
Sn)ꢁ
12.39
SiCH2),
Hz),
/
28 Hz,
(s,
1J(13CÁ29
1J(13CÁ117/119
(1J(13CÁ117/119
/
Si)ꢁ
/
52
Hz;
327/342
Me3Si),
Hz;
/
Sn)ꢁ
/
23.36
24.03
/
Sn)ꢁ
/
503/526
ing scheme of the form wꢁ
/
1/[s2(Fo)2ꢀ
/
(0.0848P)2ꢀ
/

J. Beckmann et al. / Journal of Organometallic Chemistry 688 (2003) 56Á
/61
61
(F2oꢀ2F2c)/3 was applied. Most Sn
/
A. Orita, J. Otera, D. Dakternieks, A. Duthie, J. Organomet.
Chem. 574 (1999) 176;
48.442P] where Pꢁ
/
atoms had a significant residual electron density peak
(c) M. Schulte, M. Schurmann, D. Dakternieks, K. Jurkschat, J.
¨
/
2.4 e Aꢂ3) in close proximity, indicating some
˚
(B
Chem. Soc. Chem. Comm. (1999) 1291;
disorder operating in the structure. However, it was
not possible to model this. Fig. 1 showing 50%
displacement ellipsoids was drawn with ORTEP [6c].
Calculations were performed using TEXSAN [6d].
(d) M. Schulte, M. Mehring, I. Paulus, M. Schurmann, K.
¨
Jurkschat, D. Dakternieks, A. Duthie, A. Orita, J. Otera, IXth
International Conference on the Coordination and Organometallic
Chemistry of Germanium, Tin and Lead (ICCOC-GTL-9), vol.
150Á
/
151, Gordon and Breach Science Publishers, Melbourne,
Australia, 1999, p. 201;
(e) M. Mehring, I. Paulus, B. Zobel, M. Schurmann, K. Jurkschat,
¨
5. Supplementary material
A. Duthie, D. Dakternieks, Eur. J. Inorg. Chem. (2001) 153;
(f) D. Dakternieks, A. Duthie, K. Jurkschat, M. Schurmann,
¨
Crystallographic data for 6 have been deposited at the
Cambridge Crystallographic Data Centre with deposi-
tion number 211304. Copies of the information may be
obtained free of charge from The Director, CCDC, 12
E.R.T. Tiekink, Main Group Met. Chem. 25 (2002) 73;
(g) D. Dakternieks, A. Duthie, B. Zobel, K. Jurkschat, M.
Schurmann, E.R.T. Tiekink, Organometallics 21 (2002) 647.
¨
[3] M. Mehring, M. Schurmann, H. Reuter, D. Dakternieks, K.
¨
Jurkschat, Angew. Chem. Int. Ed. Engl. 36 (1997) 1112.
[4] (a) J.-M. Lehn, Science 227 (1985) 849;
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).
(b) H.J. Schneider, Angew. Chem. Int. Ed. Engl. 30 (1991) 1417;
(c) F.P. Schmidtchen, M. Berger, Chem. Rev. 97 (1997) 1609;
(d) P.D. Beer, P.A. Gale, Angew. Chem. Int. Ed. Engl. 40 (2001)
486.
[5] (a) J. Susperregui, M. Bayle, J.M. Le´ger, G. De´le´ris, M. Biesemans,
Acknowledgements
R. Willem, M. Kemmer, M. Gielen, J. Organomet. Chem. 545Á
/
546
(1997) 559;
We wish to thank the Australian Research Council
and The National University of Singapore (R-143-000-
186-112) for support of this work.
(b) M. Kemmer, M. Biesemans, M. Gielen, E.R.T. Tiekink, R.
Willem, J. Organomet. Chem. 634 (2001) 55.
[6] (a) P.T. Beurskens, G. Admiraal, G. Beurskens, W.P. Bosman, S.
Garc´ıa-Granda, J.M.M. Smits, C. Smykalla, The DIRDIF program
system, Technical Report of the Crystallography Laboratory,
University of Nijmegen, 1992;
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¨