Formation of cyclo- and polystannanes by dehydrogenative stannane coupling catalyzed by platinum(II) complexes

Article abstract of DOI:10.1016/j.ica.2004.01.035

Reaction of (PhMe₂P)₂PtMe₂ or [(κ²-P,N)-Ph₂PC₂H₄NMe ₂]PtMe₂ with an excess of H₂SnBu₂ or H₂SnPh₂ resulted in the

Full text of DOI:10.1016/j.ica.2004.01.035

Inorganica Chimica Acta 357 (2004) 1959–1964
www.elsevier.com/locate/ica
Note
Formation of cyclo- and polystannanes by dehydrogenative stannane
coupling catalyzed by platinum(II) complexes
*
Susan M. Thompson, Ulrich Schubert
Institute of Materials Chemistry, Vienna University of Technology, Getreidemarkt 9, Wien A-1060, Austria
Received 3 September 2003; accepted 14 January 2004
Dedicated to Professor Helmut Werner on the occasion of his 70th birthday
Abstract
Reaction of (PhMe2P)2PtMe2 or [(j2-P,N)-Ph2PC2H4NMe2]PtMe2 with an excess of H2SnBu2 or H2SnPh2 resulted in the
catalytic formation of cyclo-, oligo- and/or polystannanes. In the reaction of (PhMe2P)2PtMe2 with H2SnBu2, linear oligomeric
species H(SnBu2)nH were observed in the initial stage of the reaction, which eventually converted into cyclostannanes. Only poly-
stannanes were observed in the reaction of [(j2-P,N)-Ph2PC2H4NMe2]PtMe2 with H2SnBu2. The reactions of H2SnPh2 were similar,
but more difficult to analyze due to redistribution reactions and the formation of insoluble products. The mechanism of the reactions
is clearly different to that previously observed for HSnR3 because metal complexes indicative of oxidative addition/reductive
elimination reactions were only observed as minor products.
Ó 2004 Elsevier B.V. All rights reserved.
Keywords: Platinum complexes; Stannyl complexes; NMR spectroscopy; Cyclostannanes; Polystannanes
1. Introduction
or polystannanes by catalytic dehydrocondensation re-
actions [2].
Previous work showed that the complexes
(PhMe2P)2PtMe2, (dppe)PtMe2, [(j2-P,N)-Ph2PCH2-
CH2CH2NMe2]PtMe2 and [(j2-P,N)-Ph2PCH2CH2-
NMe2]PtMe2 catalyze the formation of distannanes
Sn2R6 by dehydrogenative coupling of HSnBu3 or
HSnPh3 [1]. The observed complexes, especially the
bis(stannyl) complexes (PhMe2P)2Pt(SnR3)2 and (dppe)-
Pt(SnR3)2 and the methyl stannyl complexes [(j2-P,N)-
Ph2P(CH2)2=3NMe2]Pt(Me)SnR3, were indicative of an
oxidative addition/reductive elimination pathway.
It is known that metal-catalyzed dehydrogenative
coupling of tertiary silanes or stannanes is more difficult
than that of secondary or primary silanes or stannanes.
The high activity of the mentioned platinum complexes
in producing distannanes prompted us to extend this
work to dihydridostannanes (H2SnR2) to obtain oligo-
In this article, NMR spectroscopic studies on the
reaction of (PhMe2P)2PtMe2 (1) or [(j2-P,N)Ph2PC2H4-
NMe2]PtMe2 (2, ‘‘(P \ N)PtMe2’’) with dihydridost-
annanes (H2SnBu2 and H2SnPh2) are presented. We will
show that cyclo- and oligostannanes (or polystannanes,
respectively) can indeed be obtained by this route.
However, the ratio between the different product
stannanes is influenced by the kind of catalyst, and
platinum stannyl complexes analogous to those identi-
fied in the reactions of the tertiary stannanes appear to
play only a minor role, i.e., the major reaction proceeds
by a different mechanism.
2. Results and discussion
2.1. Reaction of (PhMe2P)2PtMe2 (1) with H2SnnBu2
* Corresponding author. Tel.: +43-1-58801-15320; fax: +43-1-58801-
15399.
E-mail address: uschuber@mail.zserv.tuwien.ac.at (U. Schubert).
When 1 was reacted with less than five molar
1
equivalents of H2SnBu2, H NMR spectra showed the
0020-1693/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2004.01.035

1960
S.M. Thompson, U. Schubert / Inorganica Chimica Acta 357 (2004) 1959–1964
complete consumption of the starting stannane within
the first few minutes of the reaction, i.e., the charac-
teristic triplet at 4.8 ppm was no longer observed. No
clear signals were found in the 119Sn NMR spectra, in-
dicating that the initially formed tin-containing species
were in too low concentration to be observed.
the expected region for 2JPP coupling of bis(phosphines).
Hence, some sort of asymmetric R2PR0xPR00 could
2
have been formed from the de-coordinated phosphine
ligand [4]. In the proton NMR spectrum, a singlet was
observed at 4.6 ppm which can be assigned to a
HP(Ph)Me compound. The spectra were similar when a
100-fold excess of the stannane was employed.
At 1: H2SnBu2 ratios P1:5, three main regions of
overlapping 119Sn NMR resonances were seen. The
main signals were always in the region )202 to )209
ppm (which includes the signal of H2SnBu2 at )204
ppm), and further signals were found in the region )90
to )92 ppm, and )140 to )160 ppm. The )202 to )208
region corresponds to cyclostannanes ((SnBu2)5 )200.9
ppm, (SnBu2)6 )202.1 ppm; polymeric (SnBu2)n )189.6
ppm [3]). The signals in the )140 to )160 ppm region
were assigned to Pt–Sn moieties on grounds of the 2D
coupling and the chemical shift, while the signal at )92
ppm is in the region of HBu2Sn – moieties and could
represent, for example, the end of an oligomer chain.
At a molar ratio of 1:5 119Sn NMR resonances were
found at )191, )144 and )92 ppm at the start of the
reaction. The signals at )191 and )92 ppm indicate the
presence of H(SnBu2)nH oligomers. After reaction for
60 min, further signals were seen at )209 and )204 ppm
representing cyclostannanes.
When a 1: H2SnBu2 ratio of 1:20 was employed,
strong gas evolution was observed on addition of the
stannane, and H2SnBu2 was consumed within 4 h.
Resonances at )208 and )204 ppm representing the ring
species were immediately present after addition of the
stannane to the solution of the platinum complex.
Further resonances were also observed at )144 and )92
ppm, but the ring compounds represented 82% of the tin
species. After 3 h reaction, the only tin species identified
were cyclostannanes of different sizes. When an 100-fold
excess of stannane was used, the same trend was ob-
served, and the ring species were the main species
formed. The reactant stannane in this case was not
completely consumed within 24 h.
31P NMR spectra were taken to identify complexes
involved in the catalytic stannane coupling. On reaction
of 1 with 3–5 molar equivalents of H2SnBu2, the only
phosphorus species was 1 and de-coordinated PMe2Ph.
Apart from a very small signal at )48 ppm (see below),
no further phosphorus containing platinum complexes
were seen.
When a 1: H2SnBu2 ratio of 1:20 was employed, the
reactant platinum complex was consumed within the
first 30 min and a new platinum complex (3) at )48 ppm
was identified after 60 min. At this point, ꢀ42% of
phosphorus species in 31P NMR were PMe2Ph and 40%
the new platinum complex 3. Further unidentified
phosphorus species were also observed. One of these
species exhibited coupling in the range 18 Hz and had
another pair of signals with exactly the same coupling
constant. The value of the coupling constant was within
The NMR data strongly suggest that complex 3 is the
bis(stannyl) complex (PhMe2P)2Pt(SnBu2H)2, equiva-
lent to (PhMe2P)2Pt(SnBu3)2 when HSnBu3 was reacted
[1]. In the 31P NMR spectrum (Fig. 1), the signal of 3
had platinum satellites of 1907 Hz, both of which were
flanked with satellites with a coupling of 116 and 125
Hz. This is typical of an averaged cis-SnPtP coupling of
the two isotopes 119Sn and 117Sn [5]. At the central signal
the cis 117Sn–P coupling was found to be 116 Hz and the
cis 119Sn–P coupling 125 Hz. These values compare well
with the literature data [6]. The central signal was found
to be a doublet with a coupling of 19 Hz. This value is
2
typical of JPPtP coupling and implies the presence of a
cis-bis(phosphine) platinum complex with two different
phosphorus environments. For example, (PhMe2P)2Pt
2
(SiMe2Ph)(SiPh3) has a JPPtP coupling of 18 Hz [7].
This is unexpected for complex 3 as the phosphorus
atoms appear to be equivalent. The non-equivalence of
the two phosphorus environments possibly arises from
different orientations of the unsymmetrical stannyl
groups.
In summary, NMR spectroscopic evidence indicates
that the outcome of the reaction of 1 with H2SnnBu2 is
as shown in Eq. (1), the portion of the individual
products varying with time and depending somewhat on
the 1: H2SnBu2 ratio.
PhMe2P
PhMe2P
Me
Me
PhMe2P
PhMe2P
SnBu2H
SnBu2H
+
(SnBu2)n
H2
+
H(SnBu)nH
+
H2SnBu2
Pt
Pt
+
+ CH4
3
1
ð1Þ
The reaction of 1 with H2SnPh2 was also investigated
and similar results were obtained. The main difference
was the observation of scrambling products with respect
to the stannyl groups at the platinum center.
2.2. Reaction of (P \ N)PtMe2 (2) with H2SnBu2
When 2 was reacted with 1–3 molar equivalents of
H2SnBu2, no signals were again observed in the 119Sn
NMR spectra, probably for the same reasons as dis-
cussed above. When the molar ratio was increased to
1:4, a single, small signal was observed at )6 ppm. At a
ratio of 1:5, a signal at )154 ppm was also observed. The
identity of this compound is unclear and will be dis-
cussed later. When a larger excess of stannane was em-
ployed, the first 119Sn NMR spectrum taken after the
addition of the stannane to the reaction mixture showed
four different tin resonances of equal intensity. A signal

S.M. Thompson, U. Schubert / Inorganica Chimica Acta 357 (2004) 1959–1964
1961
PPhMe2
1
J(PtP)
3
2
117/119SnPtP)
Phosphine
J(PP)
J(cis
-
2
-40
-45
-50
-55
ppm
Fig. 1. Section from the 31P NMR spectrum of the reaction between 1 and H2SnBu2 at a ratio of 1:20 after 3 h 45 min reaction.
at )190 ppm represents polymer species. Further signals
were found at )144, )54 and )7 ppm. No indication of
ring species was seen. The signal at )7 ppm was assigned
to Me2SnBu2 and that at )54 ppm corresponds to
PhSnBu3 [8]. This stannane could arise from a scram-
bling reaction involving the phosphorus bound phenyl
groups. The identity of the final signal at )144 ppm is
also unclear, but could represent another Pt–Sn moiety.
After 19 h reaction at room temperature of the spectra
look virtually unchanged and there were still no signs of
cyclostannanes.
equimolar ratio of 2 and H2SnBu2. Up to a molar ratio
of 1:5 and with increasing reaction time, this was the
only new complex observed (Fig. 2). This resonance was
assigned with certainty to the bis(phosphine) complex
cis-(N \ P)2PtMe2 (only the phosphorus atoms of the
P \ N ligands coordinated to the Pt center). These
complexes were previously observed, when the amino
groups of the hemilabile ligand were too weakly coor-
dinating, or when the complexes (P \ N)PtMe2 were
reacted with an excess of P \ N [9]. The formation of 4,
therefore, implies that de-coordinated P \ N was present
in the reaction mixture.
When a higher ratio than 1:5 was used, further
phosphorus signals were also observed in the first
spectra taken after addition of the stannane. The first
was de-coordinated P \ N. The second was a platinum
complex at 14 ppm with satellites of 1963 Hz. Based on
its chemical shift and coupling constant, this was as-
signed to (P \ N)PtMe(SnBu2H) (5). After 19 h reaction
at room temperature, only 5 and de-coordinated P \ N
were observed. The formation of 5 corresponds to that
of (P \ N)PtMe(SnBu3) in the reaction of (P \ N)PtMe2
with HSnBu3.
The involved metal complexes were again investi-
gated by 31P NMR spectroscopy. These spectra were
simpler than in the reaction of 2. A small signal at 16
ppm of a new complex (4) was already observed at an
4
2
1:5
24h
The reaction of 2 with H2SnBu2 can thus be sum-
marized as shown in Eq. (2).
1:5
1:4
Ph2
P
Ph2
P
Ph2
P
Me
Me
SnBu H
2
Me
Me
2N
Pt
Pt
Pt
+ H2SnBu2
+
P
Me2
N
Me
Me
N
Me2
N
Me2
ð2Þ
Ph2
5
4
2
+
MeSnBu + H(SnBu ) H
3 2 n
1:3
1:1
The reaction of H2SnBu2 was also investigated with
the deuterated complex 2, i.e., where the platinum
bound methyl groups were replaced with CD3 groups.
This enabled the fate of the methyl groups to be fol-
lowed in H NMR spectra. Equimolar amounts of the
reactants were used and the reaction followed the same
course as with the normal complex 2. When analyzing
2
45
40
35
30
25
20
15
ppm
Fig. 2. Section from 31P NMR spectra of the reaction between 2 and
H2SnBu2 with varying molar ratios (Pt:Sn).

1962
S.M. Thompson, U. Schubert / Inorganica Chimica Acta 357 (2004) 1959–1964
From addition of the stannane and throughout the
course of the reaction, a white solid precipitated out of the
reaction mixture. It is not unexpected that phenyl-
substituted tin species precipitate out, due to their known
low solubility. The solid state 119Sn NMR spectrum
showed a cluster/multiplet of resonances in the region
from )99 to )172 ppm. A variety of distannanes, as would
be expected given the HSnPh3 in solution, other tetraorg-
anylstannanes, and also oligostannanes of varying length
are probably present. The 13C NMR spectra showed only
resonances in the phenyl region. Again no evidence for
precipitated platinum complex was observed.
3. Conclusions
Fig. 3. Section from 2H NMR spectra from the reaction of deuterated
2 with H2SnBu2. Throughout the course of the reaction, further
equivalents of stannane were added to the reaction mixture.
In each reaction investigated in this work, clear
spectroscopic evidence for the catalytic formation of
cyclo-, oligo- and/or polystannanes by dehydrogenative
coupling was obtained, although the ratio between the
various products varied with the employed catalyst. In
the reaction of H2SnBu2 (similar for H2SnPh2) catalyzed
by 1, linear oligomeric species H(SnBu2)nH were clearly
observed in the initial stage of the reaction and at rather
low 1: H2SnBu2 ratios. This is not unexpected, because
linear oligostannanes are the kinetically formed prod-
ucts, which eventually convert into the thermodynami-
cally favored cyclostannanes.
With the latter in mind, the observation is interesting
that only polystannanes and no cyclostannanes were
formed from H2SnBu2 with 2 as the catalyst. The ab-
sence of a NMR signal at )92 ppm, typical of chain-
terminating HBu2Sn moieties, indicates that polymers
with higher molecular mass are probably formed than in
the reaction catalyzed by 1.
2
the H NMR spectra, the reduction in the intensity of
the methyl group trans to nitrogen was clearly seen
with the ongoing reaction (Fig. 3).
After 15 h reaction at room temperature only one of
the original platinum bound methyl groups of 2 was
identifiable, indicating the formation of 4. Furthermore,
there was evidence of a new platinum bound methyl
group, as would be expected through the creation of
deuterated 5. At ratios of 1:3 and a total reaction time
>4 h, further deuterium species were observed in the
form of a broad mound in the region between 0.2 and
0.6 ppm. The resolution of this signal did not improve
with reaction time.
The reactions of H2SnPh2 are more difficult to ana-
lyze than that of H2SnBu2 due to the formation of
sparingly soluble or insoluble species and scrambling
reactions of the substituents at the tin atoms. The latter
was also observed in the reactions of HSnPh3 [1].
However, there is spectroscopic evidence that the reac-
tions of H2SnPh2 proceed along the same line than those
of H2SnBu2.
Oxidative addition/reductive elimination reactions
analogous to that seen with HSnR3 [1] or HSiR3 [10]
also occur for H2SnR2, as indicated by formation of the
complexes 3 and 5. However, these reactions appear
only to be side reactions. In reaction of both 1 and 2, the
starting platinum complex was immediately consumed
and de-coordinated PMe2Ph or P \ N was produced. In
the latter case this fact manifested itself also in the in-
stant formation of the bis(phosphine) complex 4, with
two open P \ N ligands. The bis(phosphine) complex 4 is
an analog to 1, and therefore undergoes similar reac-
tions, i.e., with time it was seen that de-coordinated
2.3. Reaction of (P \ N)PtMe2 (2) with H2SnPh2
The reaction of 2 with a 20-fold excess of H2SnPh2
was also carried out. In contrast to the reaction with
H2SnBu2, the 31P NMR spectrum gave no evidence of
platinum complexes. The only resonance identifiable
was that of the de-coordinated P \ N ligand.
Cyclic and polymeric species were identified in 119Sn
NMR spectra taken directly after the addition of the
stannane to the solution of 2. Furthermore, an intense
resonance was observed at )163 ppm representing
HSnPh3. The presence of this stannane was confirmed by
1H NMR spectroscopy. Additional two signals were
found at )134 and )102 ppm in the 119Sn NMR spectra,
these were relatively low in intensity and were previously
assigned to Pt–Sn moieties. The signal at )102 ppm also
exhibited 2D coupling with the platinum complex region,
further supporting this theory. During the course of the
reaction the spectra remained similar, but the number of
resonances in the ring/polymer region increased.

S.M. Thompson, U. Schubert / Inorganica Chimica Acta 357 (2004) 1959–1964
1963
P \ N was also formed. Then, from this point, the two
complexes react in a similar manner.
in 0.3 ml of C6D6 with exclusion of light. The addition
of stannane produced very strong gas evolution and a
color change to yellow was observed. After 3.5 h, traces
of a fine black solid (probably elemental platinum) were
observed. The reactions with different molar ratios of 1
and H2SnBu2 were performed similarly.
When analyzing these results, it is obvious that a
significant proportion of platinum is unaccounted for.
No elemental platinum was formed and the metal atoms
originally coordinated to the phosphine ligands must
still be present in solution. This implies that the plati-
num is still part of some complex. A plausible expla-
nation is that stannyl platinum complexes, without
phosphine ligands were formed. This is supported by the
fact that Pt–Sn unidentified moieties were observed in
the 19Sn NMR spectra despite the absence of corre-
sponding signals in the 31P NMR spectra.
1H NMR:
d
(ppm), 4.8 (t, with satellites,
2JðHSnHÞ ¼ 2 Hz J(117SnH) ¼ 1608 Hz, J(119SnH) ¼
1672 Hz, H2Sn); 119Sn NMR: d (ppm) )92.1 (s,
HSnBu2), )144.3 (s, Pt–Sn, 3), )191.6 (s, (SnBu2)n
polymers), )202.1 to )209.4 (m, cyclo-(SnBu2)n); 31P
NMR: d (ppm) )10.03 (s, with satellites, 1JðPtPÞ ¼ 1822
1
1
2
Hz, 1), )38.35, (d) and )42.80 (d, JPP ¼ 18 Hz,
R2PCH2PR02), )45.31 (s, PPhMe2), )48.32 (s, with
satellites, 1JðPtPÞ ¼ 1907 Hz, 2J(tr-117SnPtP) ¼ 1571
Hz, 2J(tr-119SnPtP) ¼ 1611 Hz, 2J(cis-117SnPtP) ¼ 116
4. Experimental
Hz, J(cis-119SnPtP) ¼ 154 Hz, 3).
2
All reactions were carried out in an argon atmosphere
in benzene solutions at room temperature, with as much
exclusion of light as possible. Argon was purified using
4.2. Reaction of (P \ N)PtMe2 (2) with H2SnBu2
ꢀ
Cu and molecular sieve (4 A). All solvents used were
(A) An amount of 3 mg (0.012 mmol) of H2SnBu2
was added at room temperature to 5.8 mg (0.012 mmol)
of 2 in 0.4 ml of C6D6. On addition of the stannane, the
solution turned yellow. After 90 min, in which time
NMR spectra were taken, another equivalent of
H2SnBu2 (5.8 mg, 0.012 mmol) was added and the
process repeated (ca. 90 min). A further equivalent was
then added and the process repeated again until a ratio
of 1:5 was achieved. With each further addition of the
stannane, a gentle gas evolution was observed. With
increasing reaction time, the sample became more or-
ange and traces of a white precipitate were present.
(B) An amount of 58 mg (0.25 mmol) of H2SnBu2 was
added at room temperature to 6 mg (0.012 mmol) of 2 in
0.4 ml of C6D6 with exclusion of light. The addition of
stannane produced strong gas evolution and the sample
turned orange. NMR spectra were then taken. After 4 h,
the sample was orange colored, but no solid was observed.
1H NMR: d (ppm) 4.8 (t, with satellites, 2J
(HSnH) ¼ 2 Hz, 1J(117SnH) ¼ 1608 Hz, 1J(119SnH) ¼
1672 Hz, H2Sn); 119Sn NMR: d (ppm) )6.7 (s,
SnMeBu2), )153.8 (s, oligomer/Pt–Sn), )189.4 (s,
H(SnBu2)nH); 31P{1H} NMR: d (ppm) 36.33 (s, with
satellites, 1JðPtPÞ ¼ 2072 Hz, 2), 16.42 (s, with satellites,
1JðPtPÞ ¼ 1858 Hz, 4), )10 to )18 (m, PR3), )14.43 (s,
with satellites, 1JðPtPÞ ¼ 1963 Hz, 5), )18.39 (s, PC2N).
dried and distilled at least once under argon. All NMR
measurements were carried out in deuterated benzene
(C6D6), the samples were filled and sealed in an argon
atmosphere. Benzene-d6 was pre-dried using a molecu-
lar sieve (4 A) and then made oxygen-free using the
freeze–pump–thaw method.
ꢀ
NMR experiments were taken on Bruker Avance
300 and 250 MHz spectrometers at room temperature,
unless otherwise stated, using an external standard;
TMS, SnMe4 or 85% H3PO4 for 1H, 119Sn and 31P
NMR, respectively. 31P and 119Sn NMR spectra were
1H inverse gated decoupled. Assignment of the 119Sn
NMR signals was also based on HSn–HMQC experi-
ments. Although 13C NMR spectra were also taken,
these data are not reported here, because the spectra
are very complex and do not allow an unequivocal
assignment of the signals. All NMR signals observed
throughout the course of the reaction are given in the
following paragraphs. For this reason, chemical shifts
are given without integration, as this varies throughout
the course of the reaction.
The complex (P \ N) PtMe2 was prepared as previ-
ously described [11]. The tin hydrides used were pre-
pared from the corresponding dichlorostannane using
LiAlH4 [12]. The dichlorostannanes were either pur-
chased, or prepared through comproportionation reac-
tions of 1:1 ratios of SnCl4 and SnR4 [13]. SnR4 was
prepared using a standard Grinard reaction with lithium
from the corresponding bromo-organyl group. Purity
4.3. Reaction of (P \ N)Pt(CD3)2 with H2SnBu2
An amount of 8 mg (0.035 mmol) of H2SnBu2 was
added at room temperature to 17 mg (0.035 mmol) of
deuterated 2 in 0.4 ml of C6D6. After 90 min at room
temperature, in which time NMR spectra were taken,
another equivalent of H2SnBu2 (5.8 mg, 0.012 mmol)
was added and the process repeated (ca. 90 min). The
reaction proceeded as described in Section 4.2.
was controlled using H and 119Sn NMR spectra.
1
4.1. Reaction of (PhMe2P)2PtMe2 (1) with H2SnBu2
An amount of 112 mg (0.479 mmol) of H2SnBu2 was
added at room temperature to 12 mg (0.024 mmol) of 1

1964
S.M. Thompson, U. Schubert / Inorganica Chimica Acta 357 (2004) 1959–1964
2H NMR: d (ppm) 0.12–0.22 (m,
D
-MeSn), 0.40–0.61
2
Acknowledgements
(m,
D
-MeSn), 1.25 (d, with satellites, JðHDÞ ¼ 1 Hz,
2JðPtCDÞ ¼ 10 Hz, cis-
D
2
-MePt,
D
-2), 1.70 (d, with sat-
-MePt,
Support by the Fonds zur Forderung der wissens-
chaftlichen Forschung (FWF), Austria is gratefully ac-
knowledged.
€
2
ellites, JðHDÞ ¼ 1 Hz, JðPtCDÞ ¼ 14 Hz, tr-
D
D
-2).
4.4. Reaction of (P \ N)PtMe2 (2) with H2SnPh2
References
An amount of 87 mg (0.32 mmol) of H2SnPh2 was
added at room temperature to 7.6 mg (0.016 mmol) of 2
in 0.4 ml of C6D6 with exclusion of light. The addition
of stannane produced strong gas evolution. The sample
turned orange and a white precipitate was formed im-
mediately. NMR spectra were then taken. With in-
creasing reaction time, more solid was observed. The
solid was separated and dried under a vacuum. The
solid was then analyzed by CP-MAS NMR spectros-
copy.
31P{1H} NMR: d (ppm) )18.39 (s, PC2N); 119Sn
NMR: d (ppm) )102.3 (s, Pt–Sn), )135.2 (s, Pt–Sn),
)163.3 (s, HSnPh3), )201.6 (s, (SnPh2)n), )207.5 (s,
(SnPh2)n), )216.9 (s, (SnPh2)n), )219.6 (s, (SnPh2)n).
CP-MAS 119Sn NMR: d (ppm) )74 to )172 (m,
(SnPh2)n); 13C NMR: d (ppm) 120, 130 (m, (Ph2Sn)n).
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