Interface synthesis, characterization and catalytic properties of dialkyldichlorotin and tetraalkyl distannoxane functionalities grafted to insoluble polystyrene beads by a hexamethylene spacer

Article abstract of DOI:10.1002/ejic.200400049

Insoluble polystyrene-grafted compounds of the type [(P-H) _(1-t){P-(CH₂)₆SnBuCl₂}_t] and [(P-H)_(1-t)({P-(CH₂)₆-SnBuX} ₂O)_t/2], where (P-H) represents a cross-linked polystyrene, X is Cl, OH or OOCCH₃, and t is the degree of functionalization, were synthesized from Amberlite XE-305, a polystyrene cross-linked with divinylbenzene. The compounds were characterized by elemental analysis, IR and Raman spectroscopy, solid-state ¹³C and ¹¹⁷Sn NMR spectroscopy and, where appropriate, by ¹¹⁹Sn hr-MAS NMR spectroscopy. The influence of the variable t and tin functionality on the catalytic activity of these compounds was assessed in the transesterification reaction of ethyl acetate with octanol. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.

Full text of DOI:10.1002/ejic.200400049

FULL PAPER
Interface Synthesis, Characterization and Catalytic Properties of
Dialkyldichlorotin and Tetraalkyl Distannoxane Functionalities Grafted to
Insoluble Polystyrene Beads by a Hexamethylene Spacer
[a]
[a]
[a]
[b]
´ ´
´
Monique Biesemans,* Frederic A. G. Mercier, Manu Van Poeck, Jose C. Martins,
Gilles Dumartin,[c] and Rudolph Willem[a]
Keywords: Catalysis / Heterogeneous catalysis / NMR spectroscopy / Transesterification / Tin
Insoluble polystyrene-grafted compounds of the type
[(P−H)(1−t){P−(CH2)6SnBuCl2}t] and [(P−H)(1−t)({P−(CH2)6-
SnBuX}2O)t/2], where (P−H) represents a cross-linked poly-
man spectroscopy, solid-state 13C and 117Sn NMR spectro-
scopy and, where appropriate, by 119Sn hr-MAS NMR spec-
troscopy. The influence of the variable t and tin functionality
styrene, X is Cl, OH or OOCCH3, and t is the degree of func- on the catalytic activity of these compounds was assessed in
tionalization, were synthesized from Amberlite XE-305, a
polystyrene cross-linked with divinylbenzene. The com-
the transesterification reaction of ethyl acetate with octanol.
( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
pounds were characterized by elemental analysis, IR and Ra- Germany, 2004)
Introduction
on the catalytic activity of these compounds. Furthermore,
based on the work of Otera and co-workers,[9] which pro-
poses the use of distannoxanes [XR2SnOSnR2Y]2 (R ϭ Bu,
Me; X ϭ Cl, NCS; Y ϭ OH, Cl, NCS) as efficient catalysts
in transesterification reactions, distannoxanes grafted
While organotin compounds enjoy widespread use as ver-
satile reagents or catalysts in a large variety of organic
transformations,[1,2] their application is sometimes limited
by their toxicity.[3,4] This adverse feature is further aggra-
vated by the generally difficult quantitative removal of or-
ganotin reagents and their by-products from the reaction
mixture,[5] often making them unsuitable for the synthesis
of biological or pharmaceutical derivatives.[3,6] These con-
cerns can be alleviated by grafting the organotin reagent
onto a solid support, thereby creating so-called ‘‘clean’’ or-
ganotin reagents, which can be removed completely from
reaction products by simple filtration. In a previous paper
we reported on the synthesis[7] and characterization[7,8] of
[(PϪH)(1Ϫt){PϪ(CH2)nSnBuX2}t] (n ϭ 4, 6; X ϭ Ph, Cl; t
(degree of functionalization) ϭ 0.25Ϫ0.30]. The catalytic
activity of these compounds in the transesterification reac-
tion of ethyl acetate with simple alcohols such as octanol
appeared reasonably good.[7] The work presented here de-
scribes the synthesis of analogues with a lower degree of
functionalization, with the aim of evaluating the effect of t
to
insoluble
polystyrene,
of
the
type
[(PϪH)(1Ϫt)({PϪ(CH2)6SnBuX}2O)t/2] (X
ϭ
Cl, OH,
OOCCH3) were synthesized from the dialkyldichlorotin
precursors. Their characterization and catalytic activity are
also discussed.
Results and Discussion
Synthesis and Characterization
A
series of five dialkyldichlorotin compounds
[(PϪH)(1Ϫt){PϪ(CH2)6SnBuCl2}t] (1aϪe) with t varying
between 0.03 and 0.31 was synthesized[7,8] according to
Scheme 1.
[a]
High Resolution NMR Centre (HNMR), Department of
Polymer Science and Structural Chemistry (POSC),
Vrije Universiteit Brussel (VUB), Room 10G720, Pleinlaan 2,
1050 Brussels, Belgium
[b]
NMR and Structure Analysis Unit, Vakgroep Organische
Chemie, University of Ghent,
Krijgslaan 281 S4, 9000 Gent, Belgium
[c]
´
Laboratoire de Chimie Organique et Organometallique, CNRS
´
UMR 5802, Universite Bordeaux 1,
´
351 Cours de la Liberation, 33405 Talence Cedex, France
Scheme 1
2908
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
DOI: 10.1002/ejic.200400049
Eur. J. Inorg. Chem. 2004, 2908Ϫ2913

Dialkyldichlorotin and Tetraalkyl Distannoxane Functionalities Grafted to Insoluble Polystyrene Beads
FULL PAPER
Different degrees of functionalization were obtained by 119Sn hr-MAS NMR spectroscopy. The latter technique is
controlled variation of the amount of BuLi in the first lithi- a high resolution liquid NMR technique that is used to ob-
ation step, resulting in five (PϪH)(1Ϫt)(PϪLi)t precursor tain NMR spectra of tin-containing grafts dipped in solu-
compounds. The dependence of t on the BuLi/PϪH molar tion, in situ at the solidϪliquid interface, provided sufficient
ratio in this step is illustrated in Figure 1.
local rotational mobility can be achieved on the grafts
through matrix pore swelling by the solvent.[8]
Scheme 2
Whereas the reaction with H2O and KOH was complete
for the compounds with high t value (0.31, compounds 2e
and 3e), incomplete conversion was observed for the com-
pounds with lower t value (0.03Ϫ0.21, compounds 2aϪd,
3a؊d). This was shown by the presence of residual
ν(SnϪCl) bands in the Raman spectra of 3aϪd and the
detection of residual amounts of chlorine for 3aϪd or too
high amounts for 2aϪd by elemental analysis; the conver-
sion degree appears to be dependent on t, as illustrated in
Figure 2 and 3.
Figure 1. The experimental degree of functionalization (t) as a
function of the molar ratio BuLi/PϪH in the first reaction step of
Scheme 1
The substitution of the phenyl groups by chlorine in the
last step of the reaction in Scheme 1, previously performed
by reaction with HCl in methanol, suffered from sluggish
reactivity leading to polymers with a slight but significant
chlorine deficit.[7] In the present synthesis route, pure HCl
gas is bubbled for 15 minutes through a suspension of beads
of [(PϪH)(1Ϫt){PϪ(CH2)6SnBuPh2}t] in methylcyclohexane
at Ϫ80 °C. Using this new route, a better control over the
desired substitution reaction was obtained, since less than
2% of grafted R3SnCl side-functionality was obtained in-
stead of 6Ϫ7 % by the HCl/CH3OH method, as assessed by
solid state 117Sn MAS NMR spectroscopy and elemental
analysis. Moreover, any possible inconvenience arising from
moisture can be better avoided with the latter synthesis
route. The determination of t of all precursor compounds
and of 1aϪe (1a, t ϭ 0.03; 1b, t ϭ 0.10; 1c, t ϭ 0.12; 1d,
t ϭ 0.21; 1e, t ϭ 0.31) was performed, as described pre-
viously,[7] from experimentally obtained elemental mass
fractions of all elements involved, using a mathematical
non-linear least-squares procedure, minimizing the impact
of the elements leading to larger uncertainty margins.
Figure 2. Percentage conversion of 1 into 2 as a function of t
Since
distannoxanes,
with
general
formula
YR2SnϪOϪSnR2Y, have also proved to be efficient trans-
esterification catalysts,[9] we were interested in the conver-
sion of compounds 1aϪe into compounds of the type
[(PϪH)(1Ϫt)({PϪ(CH2)6SnBuX}2O)t/2] with X ϭ Cl, OH,
OOCCH3. The synthetic procedures leading to the different
SnϪOϪSn-bridged compounds are given in Scheme 2. The
reactions were performed twice successively, in order to
achieve full conversion as far as possible. IR and Raman
spectroscopy were used to monitor the reactions: in the Ra-
man spectra the evolution of the ν(SnϪCl) band was moni-
tored, while in the IR spectra the appearance of new bands
characteristic of the different SnϪOϪSn-bridged com-
pounds can be observed. The purity of the compounds in
Scheme 2 was determined by elemental analysis, solid state
117Sn MAS NMR spectroscopy and, where appropriate, by Figure 3. Percentage conversion of 1 into 3 as a function of t
Eur. J. Inorg. Chem. 2004, 2908Ϫ2913
www.eurjic.org  2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 2909

M. Biesemans et al.
FULL PAPER
The explanation for this observation is to be found in the Catalytic Activity
lack of sufficient neighbouring grafted functionalities,
which are necessary to generate SnϪOϪSn cross-links, in
the compounds with low functionality.
In order to evaluate the catalytic activity of the grafted
organotins in 1Ϫ4, the reaction between ethyl acetate and
octanol (Scheme 3) was investigated. The degree of conver-
sion was calculated from the ratio of initial alcohol to ob-
tained ester by integration of the respective CH2O 1H NMR
resonances. The results are summarized in Table 2.
Further evidence for residual ϪSnCl2 functionalities was
found in the 119Sn hr-MAS spectra of 2aϪd and 3aϪd,
which still show resonances for this functionality. This tech-
nique, which is used to obtain high resolution liquid-like
119Sn NMR spectra of solvent-swollen beads of
[(PϪH)(1Ϫt){PϪ(CH2)6SnBuCl2}t],[8] in which the tin func-
tionality acquires local rotational mobility, was disap-
pointingly uninformative for 2e and 3e, where complete
conversion was obtained. In fact, no 119Sn NMR resonance
could be generated, probably due to the rigidity of the dis-
tannoxane moiety by the additionally introduced
SnϪOϪSn cross-linking, preventing sufficient rotational
mobility necessary for this technique to be successful.
When reacting 1e with CH3COOK in methanol, it was
unclear beforehand whether grafted tin compounds of the
distannoxane type, [PϪ(CH2)6SnBuOOCCH3]2O, or of the
tin dicarboxylate type, PϪ(CH2)6SnBu[OOCCH3]2, with
both chlorides substituted by acetate, would be obtained,
since the synthesis of a compound similar to the latter has
already been described in the literature, although in this
case the tin moiety is grafted directly to the phenyl rings of
an insoluble polystyrene matrix.[10] Therefore, the theoreti-
cal mass fractions were calculated for both models using
the functionalization degree of the precursor 1e. When these
calculated values were compared to those determined by
elemental analysis, the mass fractions, especially the ones
for carbon and tin calculated for the SnϪOϪSn model, fit-
ted the experimental values better (see Table 1). Moreover,
the positions of the ν(CϭO) bands in the IR spectrum of
4e differ from those of the model dicarboxylate compound
Bu2Sn(OOCCH3)2, while other characteristic bands of the
latter are not found. This favours the proposal that the ob-
tained compound is indeed of the distannoxane type, as is
the case for those obtained by reaction of 1 with H2O or
KOH.
For the compounds [(PϪH)(1Ϫt){PϪ(CH2)6SnBuCl2}t]
with variable functionalization degree, two types of experi-
ments were performed. Entries 1Ϫ4 (type A) were carried
out with a constant mass of catalyst (367 mg, correspond-
ing to 1 mol % of 1e), and consequently a variable molar
amount of tin sites. Entries 5Ϫ7 (type B) describe reactions
with 1 mol % of catalyst (% Sn with respect to octanol). In
the first series reasonably good results were obtained for all
compounds, with a maximum conversion obtained for t ϭ
0.21, which appears to be the optimal functionalization de-
gree for the catalytic activity (see Table 2). In the second
series a slight decrease in conversion was observed with in-
creasing t. Both data sets are in agreement with a better
accessibility of the reagents to the catalytic centre at a mod-
erate degree of functionalization, emphasizing the need to
find the optimum compromise between having a sufficient
number of catalytic sites and avoiding side-chain entangle-
ment due to a too high degree of functionalization.
As far as the distannoxanes are concerned, the catalytic
activity is reported for the functionally pure compounds 2e,
3e and 4e only. Although a decreased molecular mobility
of the grafted tin functionality is to be expected due to the
introduction of SnϪOϪSn bridges, good conversion de-
grees, comparable (or slightly higher) to those of the precur-
sor compound 1e, were obtained when using these com-
pounds as catalysts in the transesterification reaction of
ethyl acetate with octanol (Table 2; entries 8Ϫ11).
The chemical stability of the catalysts under reaction was
assessed by solid state 117Sn CP-MAS NMR spectroscopy,
at least within the signal-to-noise conditions under which
the spectra were obtained. The spectra of compounds 1e
and 2e, after their use as a catalyst, are reasonably superim-
posable on the spectra of the same compounds before ca-
talysis. The isotropic chemical shift is found at the same
position and no evidence for significant generation of new
functionalities can be seen. By way of an example, Figure 4
shows the 117CP-MAS spectrum of 2e prior to and after a
transesterification experiment for 48 hours.
Table 1. Comparison of the experimental mass fractions of com-
pound 4e with the theoretical ones using different models
Model
γC (%)
γH (%)
γSn (%)
In contrast, the grafted HOSnϪOϪSnOH (3e) and
CH3COOSnϪOϪSnOOCCH3 (4e) compounds are chemi-
cally modified during the reaction. Only very ill-defined
noisy spectra of these compounds could be obtained, under
Experimental mass fractions
[PϪ(CH2)6SnBuOOCCH3]2O
PϪ(CH2)6SnBu[OOCCH3]2
68.80
68.52
66.98
7.54
7.43
7.32
18.50
17.99
16.70
Scheme 3
2910
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
Eur. J. Inorg. Chem. 2004, 2908Ϫ2913

Dialkyldichlorotin and Tetraalkyl Distannoxane Functionalities Grafted to Insoluble Polystyrene Beads
FULL PAPER
Table 2. Catalytic activities of dialkyltin- and distannoxane-functionalized polystyrenes in the transesterification of ethyl acetate with oc-
tanol
Entry
Catalyst
Type[a]
t
Conv. after 24 h (%)
Conv. after 48 h (%)
1
2
3
4
5
6
7
8
1b
A
A
A
A
B
B
B
B
B
B
B
0.10
0.12
0.21
0.31
0.12
0.21
0.31
0.31
0.31
0.31
0.31
58
65
89
74
84
80
74
78
72
54
58
87
88
94
89
95
94
89
96
94
90
87
1c
1d
1e
1c
1d
1e
2e
9
10
11
3e
4e
4e (re-used)
[a]
A: 367 mg of catalyst, corresponding to 1 mol % Sn with respect to octanol for 1e, was used; B: 1 mol % Sn (variable mass) with
respect to octanol.
Figure 4. 117Sn CP-MAS spectra of 2e prior to (A) and after (B) a transesterification experiment
identical acquisition conditions as for the compound before terification reaction of ethyl acetate with octanol. Evidence
its use as a catalyst, indicating that the organotin grafts are was found for the existence of an optimal degree of func-
altered during the activation process. The identification of tionalization, interpreted as a compromise between having
the distannoxane compounds was therefore impossible. a sufficient number of catalytic sites and avoiding side-chain
Notwithstanding this observation, the catalyst was amen- entanglement due to a too high degree of functionalization.
able to a second transesterification run to provide an ident-
The dialkyldichlorotin-grafted polystyrenes were con-
ical conversion yield as in the first run within experimental verted into three types of tetraalkyldistannoxanes by reac-
error (entry 11 in Table 2). However, as they are chemically tion with water, hydroxide or acetate. Complete conversion
unstable, their potential as catalysts is less reliable than for could only be obtained with a sufficiently high degree of
2e, which appears to be both efficient and reasonably functionalization. Their catalytic activity was similar to that
chemically stable, at least for the model reaction investi- of the dialkyldichlorostannanes.
gated during this work.
Experimental Section
Conclusion
Synthesis of [(P؊H)(1؊t){P؊(CH2)6SnBuCl2}t] (1aϪe): The poly-
Dialkyldichlorotin-grafted polystyrene compounds were
obtained with variable degree of functionalization. All com-
mers were synthesized as summarized in Scheme 1, following a pro-
cedure described previously,[7] modified in the last step to allow for
pounds showed reasonable catalytic activity in the transes- a better control of possible side-reactions.[8] In all cases, a divi-
Eur. J. Inorg. Chem. 2004, 2908Ϫ2913
www.eurjic.org
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2911

M. Biesemans et al.
FULL PAPER
nylbenzene cross-linked polystyrene, Amberlite XE305 (PolySci-
ences Inc.), was used as the insoluble solid support PϪH. In short,
a hexamethylene spacer with terminal chloride was grafted onto
the insoluble polystyrene PϪH, preliminarily lithiated to different
extents in the para position, by varying the amount of BuLi. In the
next step a stannylation reaction with Ph2SnBuLi in THF substi-
tuted the chlorine atom for the BuPh2Sn group. The BuCl2Sn func-
tionality in compound 1 was obtained by reaction with HCl gas
at Ϫ78 °C in methylcyclohexane.[8] IR (cmϪ1): ν(SnϪCl) 340 (m);
νsym(SnϪBu) 515 (w); νasym(SnϪBu) 595 (w). (C8H8)(1Ϫt)(C18H28Cl2Sn)t
1a (t ϭ 0.033): calcd. C 86.97, H 7.59, Cl 2.03, Sn 3.40; found C
86.96, H 7.78, Cl 3.07, Sn 2.63. 1b (t ϭ 0.104): calcd. C 78.42, H
7.34, Cl 5.33, Sn 8.92; found C 78.19, H 7.51, Cl 5.44, Sn 7.73. 1c
(t ϭ 0.117): calcd. C 77.16, H 7.30, Cl 5.81, Sn 9.73; found C77.47,
H 7.34, Cl 6.32, Sn 9.53. 1d (t ϭ 0.206): calcd. C 70.21, H 7.10, Cl
8.49, Sn 14.21; found C 70.34, H 7.19, Cl 7.86, Sn 14.46. 1e (t ϭ
0.312): calcd. C 64.50, H 6.93, Cl 10.68, Sn 17.88; found C 64.51,
H 7.24, Cl 10.56, Sn 18.08. 119Sn hr-MAS NMR: δ ϭ 124 ppm.
Raman spectra were recorded on a PerkinϪElmer 2000 NIR FT-
RAMAN spectrometer using
310 mW power.
a Raman dpy2 beam with
NMR Spectroscopic Data: Samples used for the determination of
the initial alcohol to obtained ester ratio were prepared by dissolv-
1
ing about 10 mg of mixture in 0.5 mL of CDCl3. Quantitative H
NMR spectra were recorded on a Bruker AMX500 instrument.
The 119Sn hr-MAS spectra were recorded on the same instrument
(186.50 MHz) with a specially dedicated Bruker 1H/13C/119Sn hr-
MAS probe equipped with gradient coils, by using full rotors con-
taining approximately 20 mg of resin beads, swollen in approxi-
mately 100 µL of CDCl3 and spinning at 4000 Hz around the magic
angle. External referencing with Ξ ϭ 37.290665 MHz was used.
The solid state (CP)-MAS spectra were recorded on a Bruker
DRX250 spectrometer, operating at 62.90 and 89.15 MHz for 13C
and 117Sn nuclei, respectively, using procedures described pre-
viously.[11,12] The solid state 117Sn MAS NMR spectra were decon-
voluted by total-lineshape (TLS) fitting[13,14] of the experimental
spectra using the PERCH[15] software package.
Synthesis of [(P؊H)(1؊t)({P؊(CH2)6SnBuCl}2O)t/2] (2): Typically,
0.7 g of 1 was covered by MeOH (30 mL) and heated to 60 °C.
Water (4 mL) was then added to the reaction mixture. The reaction
mixture was stirred magnetically at 60 °C for 6 hours. The solution
was removed with a capillary tube and then MeOH (30 mL) and
water (4 mL) were again added successively to the polymer beads.
The reaction mixture was kept at 60 °C for 18 hours. The obtained
Acknowledgments
M. B. and R. W. are indebted to the Fund for Scientific Research
Flanders (Belgium) (FWO) for financial support (Grant no.
9.0016.02) as well as the Research Council of the VUB for match-
ing funds.
target polymer [(PϪH)(1Ϫt)({PϪ(CH2)6SnBuCl}2O)t/2
] (2) was
washed 8 times with methanol (20 mL) and dried under vacuum at
60 °C. (C8H8)(1Ϫt)(C18H28SnClO0.5)t (t ϭ 0.31): calcd. C 67.29, H
7.23, Cl 5.57, Sn 18.65; found C 66.98, H 7.32, Cl 6.13, Sn 18.30.
IR (cmϪ1): ν(SnϪCl) 337 (m); ν(SnϪOϪSn) 602 (m); νsym(SnBu) 522(w);
νasym(SnBu) 600 (w). 117Sn MAS NMR: δiso ϭ Ϫ149 ppm.
[1]
[1a] A. G. Davies, in Chemistry of Tin, 2nd ed. (Ed.: P. J. Smith),
Synthesis of [(P؊H)(1؊t)({P؊(CH2)6SnBuOH}2O)t/2] (3): The pro-
cedure was identical to that described for 2, but instead of water a
solution of KOH (229 mg, 4.08 mmol) in MeOH (20 mL) was ad-
ded to the reaction mixture. (C8H8)(1Ϫt)(C18H29SnO1.5)t (t ϭ 0.31):
calcd. C 69.37, H 7.61, Cl 0, Sn 19.15; found C 69.62, H 7.74, Cl
0.33, Sn 19.05. IR (cmϪ1): ν(OH) 3650 (w); ν(SnϪO) 448 (w);
νasym(SnϪOϪSn) 581 (w); νsym(SnBu) 506 (w); νasym(SnBu) 601 (w). 117Sn
MAS NMR: δiso ϭ Ϫ171 ppm.
[1b]
Blackie, London, 1998, pp. 265Ϫ289.
A. G. Davies, Or-
ganotin Chemistry, VCH, Blackie, Weinheim, 1997. [1c]O. A.
Mascaretti, R. E. Furlan, Aldrich Chim. Acta 1997, 30, 55Ϫ68.
B. Jousseaume, M. Pereyre, in Chemistry of Tin, 2nd ed. (Ed.:
P. J. Smith), Blackie, London, 1998, pp. 290Ϫ387.
W. P. Neumann, M. Peterseim, React. Polym. 1993, 20,
189Ϫ205.
[2]
[3]
[4] [4a]
[4b]
M. Hoch, Appl. Geochem. 2001, 719Ϫ743.
Y. Araka-
wain, in Chemistry of Tin, 2nd ed. (Ed.: P. J. Smith), Blackie,
London, 1998, pp. 388Ϫ428. [4c] M. A. Champ, P. F. Seligman,
Organotin: Environmental Fate and Effects, Chapman & Hall,
London, 1996.
C. J. Salomon, G. O. Danelon, O. A. Mascaretti, J. Org. Chem.
2000, 65, 9220Ϫ9222 and references cited therein.
B. Delmond, G. Dumartin, in Solid-State Organometallic
Chemistry: Methods and Applications (Eds.: M. Gielen, R. Wil-
lem, B. Wrackmeyer), Wiley, Chichester, 1999, pp. 445Ϫ471,
and references cited therein.
Synthesis of [(P؊H)(1؊t)({P؊(CH2)6SnBuOOCCH3}2O)t/2] (4): The
procedure was identical to that described for 2, but instead of water
a solution of CH3COOK (400 mg, 4.08 mmol) in MeOH (20 mL)
was added to the reaction mixture. (C8H8)(1Ϫt)(C20H31SnO2.5)t (t ϭ
0.31): calcd. C 68.52, H 7.43, Cl 0, Sn 17.99; found C 68.80, H
7.54, Cl 0.40, Sn 18.50. IR (cmϪ1): νsym(CO) 1319 (w); νasym(CO) 1630
(w); ∆ν(CO) ϭ 311; ν(SnϪO) 481 (m); νasym(SnϪOϪSn) 608 (w);
[5]
[6]
νsym(SnBu) 517 (w); νasym(SnBu) 598 (w). 117Sn MAS NMR: δiso
Ϫ167 ppm.
ϭ
[7]
[8]
F. A. G. Mercier, M. Biesemans, R. Altmann, R. Willem, R.
Pintelon, J. Schoukens, B. Delmond, G. Dumartin, Organomet-
allics 2001, 20, 958Ϫ962.
Catalysis Experiments on Transesterification Reactions: Ethyl acet-
ate, used both as reactant ester and solvent, and 1-octanol (Ald-
rich) were used in a 7:1 molar ratio. A mixture of ethyl acetate
(34.1 g, 388 mmol), octanol (7.2 g, 55 mmol) and insoluble Am-
berlite-supported catalyst (1 mol % Sn with respect to octanol;
367 mg for 1e) was refluxed for 24 or 48 hours. The catalyst was
filtered off and washed with CHCl3, THF and ethanol. The ethyl
acetate was distilled off from the reaction mixture. The ratio of
initial alcohol to obtained ester was determined by integration
J. C. Martins, F. A. G. Mercier, A. Vandervelden, M. Biesem-
ans, J.-M. Wieruszeski, E. Humpfer, R. Willem, G. Lippens,
Chem. Eur. J. 2002, 8, 3431Ϫ3441.
[9] [9a]
J. Otera, T. Yano, A. Kawabata, H. Nozaki, Tetrahedron
[9b]
Lett. 1986, 27, 2383Ϫ2386.
Org. Chem. 1989, 54, 4013Ϫ4014.
Nozaki, J. Org. Chem. 1991, 56, 5307Ϫ5311.
Dan-Oh, H. Nozaki, J. Chem. Soc., Chem. Commun. 1991,
J. Otera, S. Ioka, H. Nozaki, J.
[9c]
J. Otera, N. Dan-Oh, H.
[9d]
J. Otera, N.
[9e]
1
1742Ϫ1743.
J. Otera, N. Dan-Oh, H. Nozaki, Tetrahedron
(Ϯ1 %) of the respective CH2O H NMR resonances.
1993, 49, 3065Ϫ3074.
[10]
[11]
IR and Raman Spectra: IR spectra were recorded on
a
W. M. Macindoe, A. Williams, R. Khan, Carbohydr. Res. 1996,
PerkinϪElmer System 2000 FT-IR spectrometer (MIR beam) from
200 mg dry KBr pellets containing about 5 mg of substance. The
283, 17Ϫ25.
G. Dumartin, J. Kharboutli, B. Delmond, M. Pereyre,
2912
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
Eur. J. Inorg. Chem. 2004, 2908Ϫ2913

Dialkyldichlorotin and Tetraalkyl Distannoxane Functionalities Grafted to Insoluble Polystyrene Beads
FULL PAPER
[14]
M. Biesemans, M. Gielen, R. Willem, Organometallics 1996,
15, 19Ϫ23.
M. Biesemans, R. Willem, S. Damoun, P. Geerlings, M. Lah-
cini, P. Jaumier, B. Jousseaume, Organometallics 1996, 15,
2237Ϫ2245.
R. Laatikainen, M. Niemitz, U. Weber, J. Sundelin, T. Has-
sinen, J. Vepsäläinen, J. Magn. Reson. 1996, A120, 1Ϫ10.
PERCH Version 1/99; University of Kupio, Finland, 1999.
Received January 26, 2004
[12]
[13]
[15]
Early View Article
Published Online May 6, 2004
R. Laatikainen, J. Magn. Reson. 1991, 92, 1Ϫ9.
Eur. J. Inorg. Chem. 2004, 2908Ϫ2913
www.eurjic.org
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2913