Spin chemistry of organometallic compounds. 2. Interaction of N-bromohexamethyldisilazane with allyltriorganolsilanes

Article abstract of DOI:10.1016/S0022-328X(02)01662-5

Two instances have been considered demonstrating the influence of organoelement substituent on the reactivity of radicals generated from R₃MCH₂CH=CH₂ (M = Si or Sn) in photoinduced interaction with (Me₃Si)₂

Full text of DOI:10.1016/S0022-328X(02)01662-5

Journal of Organometallic Chemistry 658 (2002) 228ꢂ234
/
www.elsevier.com/locate/jorganchem
Spin chemistry of organometallic compounds
2. Interaction of N-bromohexamethyldisilazane with
allyltriorganolsilanes
Marc B. Taraban a,*, Alexander I. Kruppa a, Nikolai E. Polyakov a, Mikhail
G. Voronkov b, Vladimir I. Rakhlin b, Stanislav V. Grigor’ev b, Olga S. Volkova a,
Rudolph G. Mirskov b, Tatyana V. Leshina a
a Laboratory of Magnetic Phenomena, Institute of Chemical Kinetics and Combustion, Street 3, 630090 Novosibirsk 90, Russia
b Irkutsk Institute of Chemistry, 664033 Irkutsk 33, Russia
Received 15 March 2002; received in revised form 28 May 2002; accepted 29 May 2002
Abstract
Two instances have been considered demonstrating the influence of organoelement substituent on the reactivity of radicals
generated from R3MCH2CHÄCH2 (MꢀSi or Sn) in photoinduced interaction with (Me3Si)2NBr. CIDNP studies has allowed to
identify two different reaction mechanisms for MꢀSi or MꢀSn which end up in two different sets of reaction products. # 2002
Published by Elsevier Science B.V.
/
/
/
/
Keywords: Homolytic substitution; Free radicals; b-Cleavage; Radical pairs; CIDNP
1. Introduction
zane (Me3Si)2NH, bromotriorganosilane R3SiBr, allyl-
hexamethyldisilazane (Me3Si)2NCH2CHÄCH2, allyl
bromide CH2ÄCHCH2Br, and corresponding addition
products.
/
Recently, we have reported the unusual photoinduced
interaction of N-bromohexamethyldisilazane (Me3-
/
Si)2NBr with allyltriethylstananne Et3SnCH2CHÄ
/
CH2
resulting in the nearly quantitative yield of allene [1].
To understand the effect of the element atom proper-
ties as well as the influence of the attached substituents
we have studied similar reactions of N-bromohexa-
methyldisilazane
with
allyltriorganosilanes
Me, Et, OMe, OEt,
The addition products (III) were isolated, though with
low yields, and characterized. Organoelement com-
pounds with the acceptor substituent of b-carbon atom
with respect to element are unstable [2,3], therefore,
during the reaction, III is partially decomposed into
bromotriorganometallanes R3MBr (I) and allylhexa-
R3MCH2CHÄCH2 (Mꢀ
/
/
Si; Rꢀ
/
Cl). It has been found that, in these cases, the direction
of the process is completely changed, and the reaction
results in a complex mixture of products, some of them
most likely originated in the secondary processes. In all
cases, main reaction products include hexamethyldisila-
methyldisilazane (Me3Si)2NCH2CHÄ
/
CH2 (II). This ex-
plains the presence of these species in the resulting
reaction mixture. The presence of the allyl bromide
* Corresponding author. Tel.: ꢁ
2350
/
7-383-233-1405; fax: ꢁ7-383-234-
/
CH2Ä
/
CHCH2Br could be due to the b-cleavage of the
E-mail address: taraban@ns.kinetics.nsc.ru (M.B. Taraban).
unstable dibromide R3MCH2CHBrCH2Br (IV)*
/
an
0022-328X/02/$ - see front matter # 2002 Published by Elsevier Science B.V.
PII: S 0 0 2 2 - 3 2 8 X ( 0 2 ) 0 1 6 6 2 - 5

M.B. Taraban et al. / Journal of Organometallic Chemistry 658 (2002) 228ꢂ
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229
intermediate product formed through the bromine
addition to the initial allylic substrate. This particular
pathway of the intermediate formation of dibromide is
in agreement with [4], where the possibility of the active
role of both (Me3Si)2N+ ×
/
and +Br radicals in the
reactions of N-bromohexamethyldisilazane has been
explicitly demonstrated.
Thus, on the basis of the isolated products, the
photoinduced interaction of (Me3Si)2NBr with allyl-
triorganosilanes could be represented by the following
scheme of the radical chain reaction (Scheme 1). The
proposed mechanism is consistent with the reference
data [5,6] on the possibility of the addition of
(Me3Si)2N+ ×
/radical to double bond.
However, the hydrogen atom abstraction from the
olefin molecule is also a very characteristic reaction
pathway for the (Me3Si)2N+ ×
/radical [4]. This process
also takes place in the reaction under study where
hexamethyldisilazane (Me3Si)2NH is one of the main
reaction products. One might propose the following
mechanism of (Me3Si)2NH formation, again, through
the radical chain reaction scheme (Scheme 2).
Unfortunately, we have failed to isolate the products
of the transformations of the abstraction product, the
Scheme 2. Formation of (Me3Si)2NH through radical chain process.
˙
allylic radical R3MCHCHÄCH2; possibly, due to their
Depending on the nature of the substituents attached
to the element, the reaction mixture could contain some
other secondary reaction products. For instance, along
with R3SiBr, the formation of Me3SiBr has been
observed which is an evidence of the exchange reaction
between bromotriorganosilane and hexamethyldisila-
zane.
further bromination. Alternatively, the (Me3Si)2N+
radical could enter the addition reaction to these allylic
species followed by the photocleavage of the resulting
adduct.
In the case of allyltrichlorosilane Cl3SiCH2CHÄ
/
CH2,
the reaction mixture also contained chlorotrimethylsi-
lane Me3SiCl also formed through the exchange reaction
of bromotrichlorosilane with (Me3Si)2NH:
Photoinduced interaction of allyltriorganosilanes was
1
also studied by means of H CIDNP. The photolysis of
allyltrimethylsilane Me3SiCH2CHÄ
Si)2NBr has allowed to detect CIDNP effects of the
protons of addition product Me3-
SiCH2CHBrCH2N(SiMe3)2, allylhexamethyldisilazane
(Me3Si)2NCH2CHÄCH2, and allyl bromide CH2ÄCHÃ
/CH2 with (Me3-
/
/
/
CH2Br (Fig. 1). Polarization was also observed in the
reactions of allyltrialkoxysilanes, however, the enhance-
ment coefficients were substantially lower. The investi-
gations of the photolytic processes directly in the probe
of NMR spectrometer have shown that the substitution
Scheme 1. Radical chain reaction of (Me3Si)2NBr and R3MCH2CHÄ
/
CH2 (MꢀSi).
/

230
M.B. Taraban et al. / Journal of Organometallic Chemistry 658 (2002) 228ꢂ234
/
Fig. 1. 1H CIDNP effects observed during the photoinduced interaction of Me3SiCH2CHÄ
initial spectrum; (b) under UV irradiation; (c) spectrum after irradiation. Numbers correspond to the proton groups of the reaction products. The
inset shows the region of ꢀNCH2-protons for the case of equal concentrations of the reagents.
/CH2 with two-fold excess of (Me3Si)2NBr in C6D6; (a)
/
of the alkyl groups at silicon atom with more acceptor
ones such as methoxy or ethoxy, will result in significant
slow down of the reaction rate, though the observation
of CIDNP effect still points to the existence of the
radical stages. In the case of allyltrichlorosilane
radical [4] (see also Scheme 1). However, taking into
account the composition of the products, the analysis of
CIDNP effects of the addition product and the resulting
allylhexamethyldisilazane CH2Ä/CHCH2N(SiMe3)2 (see
Scheme 1) will be performed assuming that these
polarization effects were formed in the RP of
+CH2CHBrCH2SiR3 and (Me3Si)2N+ free radicals.
Thus, to clarify the mechanism of the process under
study, CIDNP effects observed during the photoinduced
Cl3SiCH2CHÄ
/
CH2 containing the most active acceptor
the reaction rate
substituents*three chlorine atoms*
/
/
further drops downs, and polarization effects completely
disappear.
It is necessary to mention that the observation of
CIDNP effects testify to the fact that the products are
formed through the radical pairs (RP). From the
analogy of the earlier studied photoinduced reactions
of allyl derivatives of Si, Ge, and Sn with BrCCl3 [7,8],
interaction of Me3SiCH2CHÄ
/
CH2 with (Me3Si)2NBr
were analyzed according to the common rules (see,
Section 2 for the details) [9]. As seen from Fig. 1, the
addition product Me3SiCH2CHBrCH2N(SiMe3)2 de-
monstrates pronounced polarization of Ã
tons (dꢀ3.85 ppm, A for absorption) and much weaker
effects of ÃCHBrà (dꢀ4.48 ppm, E for emission) and
SiÃCH2Ã (dꢀ1.80 ppm, A) protons. The above dis-
/
CH2NÇ pro-
and the interactions of Et3SnCH2CHÄ/CH2 with (Me3-
/
Si)2NBr [1], the following considerations were taken into
account when analyzing the observed CIDNP effects.
RP responsible for CIDNP generation in similar photo-
initiated reactions are formed on a random encounter of
the partner radicals in the bulk (so-called F-pairs, with
/
/
/
/
/
/
tribution of the net CIDNP intensities points to the
formation of the polarization effects in the free diffusion
uncorrelated
radical
pair
(F-pair)
of
m ꢀ
/
0, see rules for analysis in the Section 2). In the
+CH2CHBrCH2SiR3 and (Me3Si)2N+ free radicals
(RP-1). Indeed, in this case, highest HFI constant and,
correspondingly, highest polarization effects should be
above mentioned papers these pairs were comprised of
radical-adduct R3MCH2CHCH2CCl3 and +CCl3 radi-
˙
cal. The RPs involving bromine atom are undoubtedly
present in the bulk, however, due to high spin-orbital
coupling of Br they are incapable to generate CIDNP
effects. In the reaction with (Me3Si)2NBr, one cannot
exclude the formation of the RP of (Me3Si)2N+ and
characteristic for a-CH2Ã
/
protons of the radical. The
addition product Me3SiCH2CHBrCH2N(SiMe3)2
should result from the cage recombination of the above
RP-1.
+
Following magnetic resonance parameters of the
partner radicals of the RP-1 were used for the analysis
of the observed CIDNP effects. The conclusions were
made assuming that g-factor of (Me3Si)2N+ radical is
˙
R3MCHCHÄCH2 radicals, since the abstraction of
hydrogen atom from the olefin by (Me3Si)2N+ radical
is postulated to be one of the basic functions of this

M.B. Taraban et al. / Journal of Organometallic Chemistry 658 (2002) 228ꢂ
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231
greater than that of its carbon-centered partner in the
radical pair, and the HFI constants of Me-protons in
(Me3Si)2N+ radical are positive. Bromosubstituted
+CH2CHBrCH2SiR3 radical has the following HFI
tion). In practice, however, this effect is not necessarily
observed in all experiments, and is dependent on the
concentration of the initial Me3SiCH2CHÄ
/
CH2. This
effect might result from one more RP formed in the act
of photodecomposition of the addition product Me3-
SiCH2CHBrCH2N(SiMe3)2. The fact that in contrast to
preparative photolysis, under more intensive irradiation
of the reaction mixture we have failed to observe the
accumulation of the addition product may mean that
this compound undergoes the photodecomposition.
Thus, by analogy with the mechanism of b-cleavage of
similarly structured tin-containing compounds [1,7] one
might expect the formation of the singlet RP (RP-2) of
the radicals resulting from the photodecomposition of
the addition product (Scheme 4).
constants: A(a-CH2)B
/
0, A(CHBr)ꢀ
/
0, A(CH2SiÃ
/
)B0
/
[10].
Absorption (A) of the Ã
/
CH2NÇ protons of the
addition product Me3SiCH2CHBrCH2N(SiMe3)2
m × o × Dg × A
ꢁ × ꢃ × ꢁ × ꢃ
(
ꢀꢁ(A);
see, Section 2 for details) suggests the possibility of the
polarized Me3SiCH2CHBrCH2N(SiMe3)2 to result from
cage recombination of RP-1. Whereas allyl bromide
1
CH2Ä
product of this pair, i.e. it will demonstrate emission
(E) of ÃCH2Br protons. Indeed, CIDNP spectra show
this emission at dꢀ3.43 ppm (Fig. 1). The presence of
the polarization effects and their sign points to the
escape of the polarized bromosubstituted
/CHCH2Br should be polarized as an escape
Following H CIDNP effects could be generated in
the RP-2: Ã/CH2Si
/
m × o × Dg × A
ꢃ × ꢁ × ꢃ × ꢃ
/
ꢀꢃ(E); emission;
+CH2CHBrCH2SiR3 radical into the bulk. In accor-
dance with above assumption, possible attack of one
bromine atom in the bulk will lead to the b-cleavage of
the resulting dibromide (Scheme 3)
Ã
/
CHBrÃ
/
m × o × Dg × A
ꢃ × ꢁ × ꢃ × ꢁ
ꢀꢁ(A); absorption;
Unfortunately, it was not possible to analyze the
polarization of allyl bromide protons at the double
and ÃCH2NÇ
/
m × o × Dg × A
ꢃ × ꢁ × ꢃ × ꢃ
bond*
initial Me3SiCH2CHÄ
ppm (ÄCH); see also Fig. 1). The signals from the
corresponding protons of allylhexamethyldisilazane
CH2ÄCHCH2N(SiMe3)2 are also located in this region
(dꢀ5.09 ppm (CH2Ä); 5.69 ppm (ÄCH)). In accordance
with the above considerations one should expect that
CH2ÄCHCH2N(SiMe3)2 resulting from the b-cleavage
/these signals overlap with the lines from the
ꢀꢃ(E); weak emission:
/
CH2 (dꢀ4.87 ppm (CH2Ä); 5.67
/
/
/
One might also expect to observe emission
m × o × Dg × A
/
(
ꢀꢃ(E))
/
/
/
ꢃ × ꢁ × ꢁ × ꢁ
/
of Me3Si-protons. Since these protons do not demon-
strate the polarization, while those of (Me3Si)2N-group
of the addition product, if polarized at all, will
demonstrate in-cage CIDNP effects. This will be the
case if the rate of b-cleavage is greater than the spin-
lattice relaxation of the protons of addition product
of (Me3Si)2NCH2CHÄ
/CH2 show the pronounced ab-
sorption (dꢀ0.30 ppm), one might conclude that the
/
contribution of RP-2 to the resulting CIDNP effects of
this group is negligible, and the observed absorption is
generated in RP-1
(T1Â
/
6ꢂ
/
7 s [7]). Thus, Ã
/
CH2Ã
/
NÇ protons (dꢀ
/
3.63
ppm) should demonstrate positive polarization (absorp-
m × o × Dg × A
ꢁ × ꢁ × ꢁ × ꢁ
(
ꢀꢁ(A))
(cf. Schemes 3 and 4).
Thus, in principle
CIDNP
effects
of
(Me3Si)2NCH2CHÄCH2 represent the superposition of
/
the contributions from the polarization’s formed in RP-
Scheme 3. Radical pair mechanism of the photoinduced interaction of
Scheme 4. Tentative pathway of the decomposition of the addition
Me3SiCH2CHÄ/CH2 in the presence of (Me3Si)2NBr.
product Me3SiCH2CHBrCH2N(SiMe3)2.

232
M.B. Taraban et al. / Journal of Organometallic Chemistry 658 (2002) 228ꢂ234
/
1 and RP-2, and the latter contribution appears to be
concentration dependent.
However, the following regularity have engaged the
attention when analyzing the mechanisms of formation
of the reaction products of the photoinduced interaction
of N-bromohexamethyldisilazane (Me3Si)2NBr with
allylic tin [1] and silicon derivatives. The definitive stage
of the formation of main reaction products is the
The additional information of the detailed mechanism
of the process under study could be also obtained from
1
the analysis of H CIDNP effects of the Me3Si-protons
of the initial (Me3Si)2NBr (emission, dꢀ
/
0.22ꢂ0.26
/
interactions in the uncorrelated radical pair (F-pair) of
+
ppm, depending on the concentration) and those of
the reaction product hexamethyldisilazane, (Me3Si)2NH
˙
R3MCH2CHBrCH2 and (Me3Si)2N radicals (Scheme
5).
(absorption, dꢀ
/
0.13ꢂ0.15 ppm). The negative polar-
/
When Mꢀ/Sn, the disproportionation of the radical
ization of (Me3Si)2NBr (E) is most likely transferred to
the molecule of the initial (Me3Si)2NBr through chemi-
cal exchange between (Me3Si)2N+ radical escaped from
the recombination of RP-1 (Scheme 3) and the initial N-
bromohexamethyldisilazane, as it has been already
shown for the photoinduced interaction of (Me3Si)2NBr
pair becomes the main reaction pathway, while for Mꢀ
/
Si, only the recombination occurs. Undoubtedly, this
difference is caused by the influence of the element
atom, and this is in agreement with the earlier obtained
evidences that the effect of silicon- and germanium-
containing substituents on the radical addition reactions
is distinctly different from that of tin-containing groups
[7,8].
with allyltriethylstannane Et3SnCH2CHÄ
/CH2 [1].
Thus, there are two instances of the influence of
organoelement substituent on the radical reactivity.
Despite the apparent triviality, these results are, in
As for the 1H CIDNP effect of (Me3Si)2NH, the
observed positive polarization of Me3Si-protons testifies
that hexamethyldisilazane is a cage recombination
product resulting from hydrogen atom abstraction
fact, unusual*the nature of the influence of organoele-
/
ment function on the direction of the process, e.g.
hydrogen atom abstraction by another radical or the
recombination, undoubtedly deserves further detailed
investigations. At this stage, one might only suggest that
organotin substituents having more pronounced donor
properties as compared with organosilicon and organo-
˙
from Me3SiCHCHÄCH2 radical by the polarized
(Me3Si)2N+ radical. Recent studies of the photoinduced
interaction of Et3SnCH2CHÄ/CH2 with (Me3Si)2NBr [1]
have shown that (Me3Si)2NH was one of the main
reaction products. The formation of (Me3Si)2NH in [1]
germanium ones, facilitate the homolytic CÃ/H cleavage.
was accompanied by generation of allene CH2Ä
/
CÄ/CH2
and R3MBr. In the present case, taking into account the
absence of allene as well as its precursor among the
reaction products and also the absence of corresponding
signals in CIDNP spectra, it is suggested that the
polarization of (Me3Si)2NH is generated from other
sources (formed in another RP). One of the possible
candidates could be the above mentioned radical pair of
2. Experimental
GLC analysis was carried out using ‘Tsvet 500’ (heat
conductivity detector, He, glass column 3 mꢄ4 mm,
10% PMS-1000 on a Chromaton N-AW-HMDS, 0.20ꢂ
0.25 mm grain). NMR spectra were taken for 10ꢂ15%
solutions in CDCl3 (‘Izotop’) by means of JEOL JNM
FX 90Q high-resolution NMR spectrometer (90 MHz
for protons) and BRUKER DPX-400 (400 MHz for
/
/
/
(Me3Si)2N+ and Me3SiCHCHÄCH2 free radicals. Un-
˙
fortunately, at this stage it is impossible to identify other
products of this RP, since the expected retention of the
double bond in these products makes it impossible to
identify their CIDNP effects due to the signal overlap
1
protons) using Me4Si, HMDS as internal standards. H
CIDNP spectra were detected by means JEOL JNM
FX90Q equipped special in-house device for the irradia-
tion of the samples directly in the probe of the spectro-
with the analogous groups of (Me3Si)2NCH2CHÄ
/
CH2,
CH2ÄCHÃCH2Br, and the initial Me3SiCH2CHÄCH2.
/
/
/
Thus, summarizing the above analysis of CIDNP
effects and judging from the set of reaction products of
the photoinduced interaction of N-bromohexamethyldi-
silazane
R3SiCH2CHÄ
conclusion could be made. In contrast to the earlier
studied reaction between (Me3Si)2NBr and
Et3SnCH2CHÄCH2 [1], the reaction under study results
(Me3Si)2NBr
with
allyltriorganosilanes
/
CH2 (Rꢀ/Me, Cl, OMe) the following
/
in a much broader set of the reaction products, there-
fore, one could not exclude the possibility of their
formation through radical chain mechanism presented
in Scheme 1.
Scheme 5. Alternative pathways of the transformations of the RP-
precursor of the main reaction products.

M.B. Taraban et al. / Journal of Organometallic Chemistry 658 (2002) 228ꢂ
/234
233
meter. Irradiation was carried out in standard Pyrex
NMR tubes using the full light of a DRSH-1000 high-
pressure mercury lamp (1 kW). A thermal filter used to
prevent the heating of the sample.
(Me3Si)2NBr. The fraction (6 g) containing Me3SiBr,
CH2ÄCHCH2Br, (Me3Si)2NH (identified by means of
/
GLC, in the ratio 2:1:6) was collected as well as CH2Ä
/
CHCH2N(SiMe3)2 (3.5 g), Et3SiBr (3.6 g), and the
The analysis of CIDNP effects was carried out using
the existing rules [9]. The sign of net CIDNP effect (G)
observed in high magnetic field is defined by the product
of multiplication of the following parameters:
addition product Et3SiCH2CHBrCH2N(SiMe3)2 (6.6
g), yield 15%, b.p. 85 8C/2 mm, n2D3ꢀ
/
1.4522; d (1H)
CH2Si);
); 2.99 (m,
in CDCl3: 0.07 (s, 18H, Me3Si); 0.57 (m, 6H, Ã
0.99 (m, 9H, CH3Ã); 0.96 (m, 2H, ÃCH2SiÃ
2H, NCH2); 3.66 (m, 1H, CHBr).
/
/
/
/
Gꢀm × o × Dg × A
where m is the multiplicity of the RP-precursor (‘ꢁ
triplet and uncorrelated pair, and ‘ꢃ’ for singlet
precursor), o is ‘ꢁ’ for ‘in-cage’ and ‘ꢃ’ for’ escape
/
’ for
2.3. Reaction of (MeO)3SiCH2CHÄ
/CH2 with
/
(Me3Si)2NBr
/
/
recombination products, Dg is the sign of difference in
g-factors of the radical with polarized nucleus and
radical partner in the RP, A is the sign of hyperfine
interaction constant of nucleus under study in the
radical. The sign of G reflects the phase of the NMR
The mixture of 14 g (0.086 M) of (MeO)3SiCH2CHÄ
/
CH2 and 21 g (0.086 M) of (Me3Si)2NBr was subjected
to UV irradiation during 4 h. The irradiation was
stopped when the reaction mixture became turbid. The
following products were isolated by fractional distilla-
tion: the mixture of Me3SiBr and (Me3Si)2NH (5.4 g) in
signal of nucleus under study: ‘ꢁ
/
’ for enhanced
absorption (A) and ‘ꢃ’ for the emission (E). For
/
the ratio 1:5, the initial (MeO)3SiCH2CHÄ
and the addition product (MeO)3SiCH2CHBrCH2N-
(SiMe3)2 (3.5 g), yield 10%, b.p. 81 8C/3 mm, n1D9ꢀ
1.4567, d (1H) in CDCl3: 0.07 (s, 18H, MeSi); 3.88 (s,
9H, (MeO)3Si); 1.87 (m, 2H, CH2Si); 3.13 (m, 2H, Ã
NCH2Ã); 4.18 (m, 1H, CHBr). CH2ÄCHCH2N(SiMe3)2
(2.7 g) has also been isolated.
/
CH2 (3.8 g),
example, if one consider certain group of, say, protons
in the product resulting from the recombination
/
(o is ‘ꢁ
/
’) of the uncorrelated RP (m is ‘ꢁ’), and if this
/
group has belonged to the radical with the g-factor
smaller than that of the partner radical of the RP (Dg is
/
/
/
‘ꢃ
/
’), and if the sign of hyperfine interaction for this
’),
particular group in the radical is negative (A is ‘ꢃ
/
then the multiplication gives
2.4. Reaction of (EtO)3SiCH2CHÄ
/CH2 with
m × o × Dg × A
ꢀꢁ(A);
(Me3Si)2NBr
ꢁ × ꢁ × ꢃ × ꢃ
The mixture of 6.6 g (0.032 M) of (EtO)3SiCH2CHÄ
/
and one should observe the enhanced absorption of the
NMR signal of this group.
CH2 and 7.7 g (0.032 M) (Me3Si)2NBr was subjected to
UV irradiation. The irradiation was stopped when the
reaction mixture became turbid. The following products
were isolated by fractional distillation: the mixture of
Me3SiBr, (EtO)3SiBr, and (Me3Si)2NH (4 g) in the ratio
2.1. Reaction of Me3SiCH2CHÄ
/
CH2 with (Me3Si)2NBr
The mixture of 11 g (0.096 M) of allyltrimethylsilane
and 23 g (0.096 M) of (Me3Si)2NBr was degassed
according to freeze-pump-thaw techinque and then
subjected to UV irradiation (UV lamp DRT-400) during
10 h in a sealed glass tube. Following product were
4:1:7, the initial (EtO)3SiCH2CHÄ
addition product (EtO)3SiCH2CHBrCH2N(SiMe3)2 (1.7
g), yield 11%, b.p. 105 8C/4 mm, n2D0ꢀ1.4582, d (1H) in
CDCl3: 0.08 (s, 18H, Me3Si); 1.34 (m, 9H, CH3Ã); 3.79
(m, 6H,ÃCH2OSi); 1.84 (m, 2H, ÃCH2Si); 3.11 (m, 2H,
NCH2); 4.2 (m, 1H, ÃCHBr).
/
CH2 (2.6 g), and the
/
/
/
/
isolated by fractional distillation: Me3SiBr (2.7 g), CH2Ä
/
ꢀ
/
/
CHCH2Br (1.3 g), (Me3Si)3NH (1.5 g), CH2Ä
/
CHCH2N(SiMe3)2 (4.5 g), and the addition product
Me3SiCH2CHBrCH2N(SiMe3)2 (3.7 g), yield 11%, b.p.
2.5. Reaction of Cl3SiCH2CHÄ/CH2 with (Me3Si)2NBr
61 8C/2 mm; n2D1ꢀ1.4127, d (1H) in CDCl3: 0.08 (s, 18
/
The mixture of 7.6 g (0.043 M) of Cl3SiCH2CHÄ
/CH2
H, Me3Si1), 0.45 (s, 9H, Me3Si2), 1.75 (m, 2H, Ã
3.63 (m, 2H, ꢀNCH2Ã), 4.53 (m, 1H, ÃCHBrÃ
/
CH2Si),
and 10.4 g (0.043 M) of (Me3Si)2NBr was subjected to
UV irradiation during 14 h. The following product were
isolated by fractional distillation: the mixture of Me3-
SiCl, Me3SiBr, Cl3SiBr, and (Me3Si)2NH (3.6 g) in the
/
/
/
/).
2.2. Reaction of Et3SiCH2CHÄ/CH2 with (Me3Si)2NBr
ratio 6:2:4:1, CH2Ä/CHCH2N(SiMe3)2 (1.5 g), and the
The reaction was carried out similar to the above
mentioned interaction of Me3SiCH2CHÄCH2 with
(Me3Si)2NBr (paragraph 1) for the mixture of 17 g
(0.11 M) of Et3SiCH2CHÄCH2 and 26.5 g (0.11 M) of
addition product Cl3SiCH2CHBrCH2N(SiMe3)2 (2.4 g),
yield 13.4%, B.p. 123 8C/3 mm, d (1H) in CDCl3: 0.42
/
(s, 18H, Me3Si); 2.26 (m, 2H, Ã
/
CH2Si); 3.87 (m, 2H, ꢀ
/
/
NCH2); 3.87 (m, 1H, CHBr). d (29Si) in CDCl3: 31.10 (s,

234
M.B. Taraban et al. / Journal of Organometallic Chemistry 658 (2002) 228ꢂ234
/
[2] R.W. Bott, C. Eaborn, B.M. Ruston, J .Organomet. Chem. 3
(1965) 445.
Cl3Si), 7.29 (s, (Me3Si)2N). The mixture also contained 4
g of unreacted Cl3SiCH2CHÄ
/
CH2.
[3] M.A. Cook, C. Eaborn, D.R.M. Walton, J. Organomet. Chem. 24
(1970) 301.
[4] B.P. Roberts, C. Wilson, J. Chem. Soc. Chem. Commun. (1978)
752.
Acknowledgements
[5] M.D. Cook, B.P. Roberts, K. Singh, J. Chem. Soc. Perkin Trans.
II (1983) 635.
Financial support of the Russian Foundation for
Basic Research (Project Number 00-03-33048) and
Federal Program of Fundamental Research ‘Highly
Reactive Intermediates’ is gratefully acknowledged.
We thank Dr. Takayuki Uno and Shin-ichi Otsu
(Analytical Instruments Division, JEOL Ltd.) who
help us to maintain JEOL NMR Spectrometer up and
running.
[6] J.C. Brand, B.P. Roberts, J.N. Winter, J. Chem. Soc. Perkin
Trans. II (1983) 261.
[7] T.V. Leshina, R.Z. Sagdeev, N.E. Polyakov, V.I. Valyaev, M.B.
Taraban, V.I. Rakhlin, R.G. Mirskov, S.Kh. Khangazheev, M.G.
Voronkov, J. Organomet. Chem. 259 (1983) 295.
[8] T.V. Leshina, V.I. Valyaev, M.B. Taraban, V.I. Maryasova, V.I.
Rakhlin, S.Kh. Khangazheev, R.G. Mirskov, M.G. Voronkov, J.
Organomet. Chem. 299 (1986) 271.
[9] R. Kaptein, Chem. Commun. (1971) 732.
[10] According to reference data from Landolt-Bornstein New Series.
¨
Numerical Data and Functional Relationship in Science and
Technology, H. Fischer, K.-H. Hellwege (Eds.); Springer-Verlag,
Berlin, 1979, Parts Bꢂ
D, g-factor of R2N+ radicals amounts to
2.0040, and the presence of the attached Me3Si-groups will
/
References
[1] M.B. Taraban, A.I. Kruppa, V.I. Rakhlin, S.V. Grigor’ev, O.S.
Volkova, R.G. Mirskov, T.V. Leshina, J. Organomet. Chem. 636
(2001) 12.
slightly increase this value. g-factor of +CH2CHBrCH2SiR3
is5/2.003, analogous species could be found in the above
reference book.