New route to monoorganotin oxides and alkoxides from trialkynylorganotins

Article abstract of DOI:10.1039/a707298h

Functional monoorganotin oxides and alkoxides are synthesised in high yield by hydrolysis or alcoholysis of the corresponding trialkynylorganotins; the hydrolytic behaviour of trialkynylorganotins is the same as for trialkoxyorganotins.

Full text of DOI:10.1039/a707298h

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New route to monoorganotin oxides and alkoxides from trialkynylorganotins
Pascale Jaumier,a Bernard Jousscaume,*a Mohammed Lahcini,b François Ribotc and Cle´ment Sanchezc
a Laboratoire de Chimie Organique et Organome´tallique, URA 35 CNRS, Universite´ Bordeaux I, 351, cours de la Libe´ration,
33504-Talence-Cedex, France
b Laboratoire de Chimie, Universite´ Cadi Ayyad, Avenue A. Khattabi, BP 618, Marrakech, Morocco
c Laboratoire de Chimie de la Matie`re Condense´e, URA 1466 CNRS, Universite´ P. et M. Curie, T54-E5, 4, place Jussieu,
75252-Paris Cedex 05, France
Table 1 Preparation of trialkynylorganotins
Functional monoorganotin oxides and alkoxides are synthe-
sised in high yield by hydrolysis or alcoholysis of the
R1
R2
Yield (%)a
corresponding trialkynylorganotins; the hydrolytic behav-
iour of trialkynylorganotins is the same as for
trialkoxyorganotins.
Me
Ph
71b
83b
79b
75b
60c
36
45
42
46
Bu
Bu
Ph
Me
Bu
Bu
Bu
Bu
Bu
Bu
Bu
Most metallic oxides can be prepared by the sol–gel process, the
starting materials being usually metallo-organic compounds
such as alkoxides.1 Hydrolysis and condensation reactions of
these precursors lead to the formation of a metal–oxo based
macromolecular network. Generally, these sol–gel derived
materials are subject to shrinkage and cracking upon solvent
removal. Incorporation of organic phases, linked to the metal
either by metal–oxygen–carbon or metal–carbon bonds, allows
a strong improvement of the mechanical properties of the
resulting hybrid materials.2,3 These types of materials have been
extensively studied with silicon,3,4 which forms hydrolytically
stable metal–carbon bonds. As tin affords such stable bonds,
and changes its coordination number and oxidation state more
readily than Si, organotin oxide derived hybrid materials should
show interesting properties. So far, few tin based hybrids have
been developed using functional organotin trialkoxides as
precursors.5 However, these precursors offer only a limited
number of polymerizable or reactive organic functionalities.5,6
Indeed, alkene-type double bonds could be introduced in the
precursors but ester groups were found to be incompatible with
both available methods of preparation of organotrialkoxytins.
Reaction of w-(alkoxycarbonylalkyl)trichlorotins with tert-
amyl alcohol in the presence of diethylamine7 did not lead to
completion because the coordination of the metal by the
functional group decreases its electrophilic properties. On the
other hand, with sodium tert-amylate, intractable compounds
were only obtained.8
4-(CH2NCH)C6H4(CH2)4
MeO2C(CH2)2
AcO(CH2)3
AcO(CH2)5
MeCHNCHCO2(CH2)5
a
Compounds 1 were isolated and fully characterised by 1H, 13C, 119Sn
b
NMR spectroscopy and mass spectrometry. Chromatography was not
c
necessary.
This compound was obtained by direct alkylation of a
tetraalkynyltin.11
Upon hydrolysis (Scheme 2), either in chloroform with
aqueous THF or in aqueous alcohols, tin–alkynyl bonds were
cleaved and Sn–O–Sn bonds were formed. For alkyltrialkynyl-
tins, R1Sn(C·CR2)3, solution 119Sn NMR spectroscopy of the
hydrolysed product showed two equally intense sharp signals at
d ca. 2280 and 2450, accompanied by two sets of satellites
2
corresponding to J(Sn–Sn) coupling constants of ca. 200 and
380 Hz.† These peaks are characteristic of the closo cluster
[(R1Sn)12(m3O)14(m2OH)6](OH)2,12,13 where six tins are five-
coordinate and six are six-coordinate. This compound was
previously obtained from the hydrolysis of tris(isopropoxy)-
butyltin.13 Thus, as these trialkynylorganotins behave similarly
to the corresponding trialkoxides, alkynyl groups appear to be
the viable substitutes for alkoxy groups. Moreover, substitution
of the alkynyl moiety by alkyl or aryl groups has no influence on
the reaction as tris(phenylethynyl)-, tri(hex-1-ynyl)- and tri-
(prop-1-ynyl)-butyltins were hydrolyzed at about the same
rate.
With 3-acetoxypropyl as substituent at the metal, a soluble
oxo-polymer‡ in which all tin atoms are six-coordinate, a
precursor of the corresponding organostannoic acid, was
formed. The strong coordinating effect14 of the functional group
disfavors five-coordinate tin and formation of the correspond-
ing closo cluster.
Thus, other precursors, filling several requirements were
sought for: they should be cleaved by water, prepared from
conveniently obtained trichlorides and, finally, they should be
as tolerant as possible towards functional groups. As alkynyltins
are moisture sensitive compounds, alkynyl groups were thought
to be good replacements for alkoxy groups. Actually, the
hydrolysis of the tin–alkynyl bond is the reverse reaction of the
useful access to alkynyltins by reaction of stannoxanes or
alkoxyorganotins with terminal alkynes.9
Reaction of trialkynylorganotins with alcohols was also
studied (Scheme 3). To our knowledge, cleavage of [4-(ethenyl-
oxy)but-1-ynyl]triethyltin with butanol giving butoxytriethyltin
Treatment10 of functional trichloroorganotins6 with 3 equiv.
of hex-1-ynyllithium (Scheme 1) led to the corresponding
alkyltrialkynyltins in good yields. They were stable enough to
be manipulated in the air for short periods of time and to be
purified by column chromatography on Florisil. Main results
are presented in Table 1.
H2O
(R2
)3SnR1
[(R1Sn)12(µ3-O)14(µ-OH)6](OH)2
– R2
H
1
2
a R1 = Bu
b R1 = 4-(CH2=CH)C6H4(CH2)4
i
R2
Li
(R2
)3SnR1
R1SnCl3
+
c R1 = AcO(CH2)5
d R1 = MeCH=CHCO2(CH2)5
1
Scheme 1 Reagents and conditions: i, toluene, 278 °C to room temp., 5 h;
purification by chromatography on Florisil
Scheme 2 Reagents and conditions: aqueous THF, 20 °C, 12 h
Chem. Commun., 1998
369

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‡ 1H NMR (250 MHz, CDCl3) d 1.0 (2 H, br). 1.9 (2 H, br), 2.0 (3 H, br),
4.1 (2 H, br); 13C NMR (62.9 MHz, CDCl3) d 20.3, 21.6, 25.1, 67.8, 171.1;
119Sn NMR (74.6 MHz, CDCl3) d 2465 (0.5 Sn), 2490 (0.5 Sn).
R3OH
(R2
)3SnR1
R1Sn(OR3)3
– R2
H
Scheme 3 Reagents and conditions: cyclohexane, 60 °C, 16 h; the
compounds were purified by distillation
1 C. J. Brinker and G. W. Scherer, Sol–Gel Science, Academic Press,
London, 1990.
2 H. I. J. Wuang, B. Orler and G. L. Wilkes, Macromolecules, 1987, 20,
1322.
3 B. M. Novak, Adv. Mater., 1993, 5, 422.
4 H. Schmidt and B. Seiferling, Mater. Res. Soc. Symp. Proc., 1986, 73,
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U. Schubert, N. Hu¨sing and A. Lorenz, Chem. Mater., 1995, 7, 2010;
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Gel Sci. Technol., 1997, 8, 529; F. Ribot, F. Banse and C. Sanchez,
Mater. Res. Soc. Symp. Proc., 1994, 346, 121.
Table 2 Preparation of trialkoxyorganotins
R1
R2
R3
Yield (%)a
Bu
Bu
Bu
Me
Bu
Me
Me
Me
Ph
Bus
55
76
80
50
59
Bui
CH2Ph
Bus
Ph
Pri
6 B. Jousseaume, M. Lahcini, M.-C. Rascle, F. Ribot and C. Sanchez,
Organometallics, 1995, 14, 685.
7 I. M. Thomas, US Pat., 3946056, 1976.
was the only previous example of this reaction.15 When primary
or secondary alcohols were used, cleavage of alkynyl groups
occurred readily upon moderate heating. Tertiary alcohols were
not acidic enough to be useful. In this way, trialkoxymethyl- and
trialkoxybutyl-tins16 were prepared in good yields and results
are presented in Table 2. The results show the higher reactivity
of trialkynylorganotins compared to organosilanes. Indeed, Si–
alkynyl bonds can be cleaved by alcohol molecules, but only at
80 °C and in the presence of F2 as catalyst.17
These results show that alkynyl derivatives of tin can be used
instead of the corresponding alkoxides in sol–gel process and
that these alkynyl derivatives are also good precursors of
alkoxides. Moreover, these new precursors offer wide scope of
opportunities for the introduction of a variety of organic
functionalities inside tin oxide based hybrid materials.
8 A. G. Davies, L. Smith and P. J. Smith, J. Organomet. Chem., 1972, 39,
279; D. P. Gaur, G. Sivastrata and R. C. Mehrotra, J. Organomet.
Chem., 1973, 63, 221.
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M. W. Logue, J. Org. Chem., 1982, 47, 2549; B. Jousseaume and
P. Villeneuve, Tetrahedron, 1989, 45, 1145.
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11 P. Jaumier, PhD Thesis, University Bordeaux 1, 1997.
12 H. Puff and H. Reuter, J. Organomet. Chem., 1989, 373, 173;
D. Dakternieks, H. Zhu, E. R. T. Tiekink and R. Colton, J. Organomet.
Chem., 1994, 476, 33.
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Chem., 1995, 34, 6371.
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P. Jaumier and B. Jousseaume, Organometallics, 1996, 15, 2237.
15 V. S. Zavgorodnii, B. I. Ionin and A. A. Petrov, J. Gen. Chem. USSR,
1967, 37, 898.
16 J. D. Kennedy, W. McFarlane, P. J. Smith, R. F. M. White and L. Smith,
J. Chem. Soc., Perkin Trans. 2, 1973, 1785.
17 R. J. P. Corriu, J. J. E. Moreau, P. Thepot and M. Wong Chi Man, Chem.
Mater., 1996, 8, 100.
Notes and References
* E-mail: b.jousseaume@lcoo.u-bordeaux.fr
†
119Sn NMR [74.6 MHz, CDCl3, 2J (119,117Sn–119Sn)/Hz] 2a d 2282.2 (J
380, 177), 2449.0 (J 380, 205); 2b d 2280.0, 2470.4 (unresolved
satellites); 2c d 2280.7 (J 373, 178), 2443.7 (J 373, 207); 2d d 2282.2,
2449.0 (unresolved satellites).
Received in Cambridge, UK, 9th October 1997; 7/07298H
370
Chem. Commun., 1998