Reaction of hexylsilane with N-substituted allylamine and allyl chloride

Article abstract of DOI:10.1134/S1070363206040086

Reactions of allyldiethylamine and allylbis(trimethylsiyl)amine with hexylsilane are studied. The former reaction involves hydrogen evolution and Si-Si bond formation. The contribution of hydrosilylation is insignificant. Substituent exchange between the nitrogen and silicon atoms in the silane is found. In the reaction with allylbis(trimethylsilyl)amine, no evolution of hydrogen is observed, and hydrosilylation takes place. With allyl chloride, hydrosylilation, reduction, and Si-Si bond formation are observed. Quantumchemical calculations for the reactions with diethylallylamine and allylbis(trimethylsilyl)amine were carried out at the PM3, B3LYP/6-31G**, and B3LYP/LanL2DZ levels to show that these reactions all are thermodynamically allowed, and the difference in the behavior of the amines is explained by kinetic and conformational factors. Pleiades Publishing, Inc., 2006.

Full text of DOI:10.1134/S1070363206040086

ISSN 1070-3632, Russian Journal of General Chemistry, 2006, Vol. 76, No. 4, pp. 541 544.
Pleiades Publishing, Inc., 2006.
Original Russian Text Z.V. Belyakova, P.A. Strozhenko, E.A. Chernyshev, S.P. Knyazev, O.G. Shutova, T.V. Shcherbakova, 2006, published in Zhurnal
Obshchei Khimii, 2006, Vol. 76, No. 4, pp. 571 574.
Reaction of Hexylsilane with N-Substituted Allylamine
and Allyl Chloride
Z. V. Belyakova*, P. A. Strozhenko*, E. A. Chernyshev*,
S. P. Knyazev**, O. G. Shutova*, and T. V. Shcherbakova**
*
State Research Institute of Chemistry and Technology of Organoelement Compounds,
sh. Entuziastov 38, Moscow, 111123 Russia
fax: 007(495)2731323
e-mail: eos2004@inbox.ru
** Lomonosov Moscow State Academy of Fine Chemical Technology, Moscow, Russia
Received August 1, 2005
Abstract Reactions of allyldiethylamine and allylbis(trimethylsilyl)amine with hexylsilane are studied.
The former reaction involves hydrogen evolution and Si Si bond formation. The contribution of hydrosilyla-
tion is insignificant. Substituent exchange between the nitrogen and silicon atoms in the silane is found. In the
reaction with allylbis(trimethylsilyl)amine, no evolution of hydrogen is observed, and hydrosilylation takes
place. With allyl chloride, hydrosylilation, reduction, and Si Si bond formation are observed. Quantum-
chemical calculations for the reactions with diethylallylamine and allylbis(trimethylsilyl)amine were carried
out at the PM3, B3LYP/6-31G**, and B3LYP/LanL2DZ levels to show that these reactions all are thermo-
dynamically allowed, and the difference in the behavior of the amines is explained by kinetic and conforma-
tional factors.
DOI: 10.1134/S1070363206040086
We previously showed that the reaction of allyl-
amine with hexylsilane involves dehydrocondensation
to form a Si Si bond as the major pathway [1]. To
exclude dehydrocondensation and assess the effect of
substituents on the relative contributions of hydro-
silylation and Si Si bond formation, we took com-
pounds CH =CHCH X [X = NEt , NAll , N(SiMe ) ]
as objects for study. The reaction of hexylsilane with
triallylamine gave polymer that was not investigated
in the present work.
(SiMe ) ion formed from C H SiH CH(CH )CH N
3 2 6 13 2 3 2
(SiMe ) by cleavage of the bond with respect to
3
2
nitrogen [2]. The mass spectrum of possible di- and
triadducts contains no molecular ion peaks, but con-
tain a peak at m/z 174. In the UV spectrum, the Si Si
absorption band at 320 330 nm is absent.
2
2
2
2
3 2
By contrast, the reaction of diethylallylamine with
hexylsilane involved vigorous hydrogen evolution to
form compounds I [Eq. (2)].
In the course of hydrosilylation of allylbis(trime-
thylsilyl)amine with hexylsilane, no hydrogen evolu-
tion was observed. The reaction mixture contained
nC H SiH
H[C H SiH] H + (n
1)H2, (2)
6
13
3
6
13
n
Ia, Ib
n = 3 (a), 4 (b).
36% of monoadduct and, probably, di- and triadducts
[
Eq. (1)].
About 28% of such compounds were found in the
reaction mixture. In their mass spectrum, successive
evolution of hexane (m/z 84) was observed.
(
Me Si) NCH CH=CH + C H SiH
3
2
2
2
6
13
3
(
Me Si) NCH CH CH SiH C H
3 2 2 2 2 2 6
13
The UV spectrum in THF shows a band at 320
330 nm, implying presence of a Si Si bond [3].
+
[(Me Si) NCH CH CH ] SiHC H
3 2 2 2 2 2 6 13
+
[(Me Si) NCH CH CH ] SiC H .
(1)
The reaction mixture also contains about 1% of
3
2
2
2
2 3
6 13
[
-(diethylamino)propyl]hexylsilane. Its mass spec-
The mass spectrum of hexyl[ -bis(trimethylsilyl)-
trum contains a molecular ion peak and the base peak
at m/z 86 ([CH NEt ] ) formed by cleavage of the
bond with respect to nitrogen.
+
aminopropyl]silane contains an [M 1] peak and also
2
2
+
a peak at m/z 174 corresponding to the CH =N
2
541

542
BELYAKOVA et al.
(3)
Et NCH CH=CH + C H SiH
3
2
2
2
6
13
RSiH + CH =CHCH Cl
3
2
2
Et N(CH ) SiH C H .
II
2
2 3
2 6 13
R
A
Among the products of the reaction of hexylsilane
with diethylallylamine, allyl(ethyl)(hexyl)amine
13%), diethyl(hexenyl)amine (11%) and allyl(ethyl)-
hexenyl)amine (10%) were found, as well as a com-
plex of hexylsilane with diethylallylamine evidently
containing a Si N bond. Its molecular mass is equal
to that of the hydrosilylation product, but their frag-
mentation patterns are different. The mass spectrum
C H + RSiH Cl
RSiH R
3
6
2
2
(
(
III
II, R III
IV
V, 7%
II, R
III
II, A
RSiHCl2
RSiHClR
(5)
VI
VII, 22%
III, A
II, A
of the complex contains a molecular ion peak (m/z
II, R
II, R III
+
2
29), the base peak at m/z 102 ([H SiNEt ] ), and a
2
2
peak at m/z 113 (allyldiethylamine). One of the spe-
cific features of its fragmentation is the presence of
an [M Et] peak which is incharacteristic of amines
and points to mobility of the ethyl substituent. Evi-
dence for the mobility of the allyl fragment is pro-
vided by its absence in the ion that forms the base
peak (m/z 102). Evidently, substituent exchange takes
place in the complex. The formation of hexenyl sub-
stituents can be explained by hydrogenation dehydro-
genation of the allyl and hexyl substituents. Poly-
silanes contain the ethyl substituent along with hexyl.
Analogous complexes in the reactions with allylamine
and allylbis(trimethylsilyl)amine were not found.
RPrSiCl2
VIII, 1%
RSiCl R
RSiClPrR
X, 8.4%
2
IX, 14.2%
R = C H , R = CH CH CH Cl, A is addition
6
13
2
2
2
and R is reduction
The structure of the compounds was confirmed by
the mass spectra which contain molecular and [M 1]+
ion peaks, and the fragmentation patterns do not
contradict the proposed structures. Moreover, the
mixture contains 17 compounds (1 4% each, 25%
total). In their mass spectra we observe consecutive
loss of either propylene or hexene with preservation of
ions containing 1 4 chlorine atoms. Evidently, they
can be assigned formula X[C H SiH] [C H SiCl]
Et NAll + C H SiH
C H SiH EtNAll
6 13 3
2
6
13
3
6
13
l
6
13
n
[
C H SiPr] Y.
Analysis of the electronic struc-
6
13
m
C H NEt + C H NEt + C H NEtAll. (4)
6
13
2
6
11
2
6 11
tures of the allylamines under study carried out on the
basis of quantum-chemical calculations (PM3, B3LYP/
6
ferred pathways of their reactions with hexylamine
are those involving the reaction center on the nitrogen
atom: dehydrocondensation in the case of allylamine
and polysilane formation in the case of diethylallyl-
amine. The observation of dehydrosilylation in the
case of bis(trimethylsilyl)amine can be explained by
steric hindrances for reaction by nitrogen because of
The reaction of hexylsilane with allyl chloride took
usual addition and reduction pathways to form 7% of
-chloropropyl)hexylsilane (V, 22% of chloro( -
chloropropyl)(hexyl)silane (VII), 14.2% of dichloro( -
chloropropyl)hexylsilane (IX), 8.4% of chloro( -
chloropropyl)(hexyl)(propyl)silane (X), as well as a
small amount of compounds with a Si Si bond.
-31G**, and B3LYP/LanL2DZ) shows that the pre-
(
Calculated electronic parameters of compounds CH2=
CH CH NR2 (PM3 method)
the considerable volume of the SiMe group, that is
3
2
by steric and conformational reasons. In the case of
allylamine and diethylallylamine, the nucleophilic
center on nitrogen is conformationally accessible,
whereas in allylbis(trimethylsilyl)amine it is con-
formationally shielded. All the considered patways of
the reactions of allylamine with hexylsilane are
thermodynamically allowed ( G < 0).
Parameter
R = H
R = Et R = SiMe3
Atom
Si
C
C
N
Charge
0.462
1
0.153
0.140
0.310
0.136
0.173
0.081
0.161
0.172
0.281
2
Note that the divergence of calculated interatomic
distances from known experimental data are within
the experimental error and do not exceed 2 3% for
the N Si bond and 0.5 1% for the C C and C N
bonds. The atomic charge distributions are poorly
informative and contradictory (see table). At the same
time, analysis of the parameters of the frontier orbitals
Energies of frontier MOs, eV
HOMO ( -MO), eV 9.33004 9.06124
HOMO-1( -MO), eV 10.42615 10.18916
8.32826
9.74425
0.42632
1.16475
LUMO, eV
1.09583
3.0185
1.10778
2.46832
LUMO+1, eV
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 76 No. 4 2006

REACTION OF HEXYLSILANE WITH N-SUBSTITUTED ALLYLAMINE
543
points to prevailing contribution of nitrogen in the
HOMO (74 79%). This orbital is a orbital, which
suggests localization of the most active nucleophilic
center in the allylamines on the nitrogen atom. Note
that the HOMO energy increases in the series allyl-
amine < diethylallylamine < allylbis(trimethylsilyl)-
amine, implying increasing nucleophilicity (electron-
donor ability) of the corresponding reaction centers.
The second, less active nucleophilic center in the
molecules in hand is localized on the carbon atoms of
the double bond (HOMO-1). The activity of these
reaction centers increases along the same series. It is
characteristic that the HOMO-1 energy in allylbis(tri-
methylsilyl)amine is close to that in allylamine (see
table). Evidently, in allylbis(trimethylsilyl)amine with
its conformational hindrances at the nitrogen atom,
this circumstance opens the way for hydrosilylation.
The LUMO in allylamine and allyldiethylamine
relates to the *-MO of the double bond, and in allyl-
bis(trimethylsilyl)amine it is a -MO mostly con-
tributed by Si and N (the total contribution is 54%).
(ethyl)(hexyl)amine {mass spectrum, m/z (I , %):
rel
+
+
+
169 [M] (10), 154 [M Me] (8), 140 [M Et] (4),
+
+
126 [M Pr] , 97 [EtN(CH CH) ] (100), 72 (14)};
2
2
14% of compound Ia, n = 3 {mass spectrum,
+
+
m/z (I , %): 345 [M+1] (0.2), 86 [C H ]
rel
6
14
(100)}; and 31.1% of compound Ib, n = 4 {mass
+
+
spectrum, m/z (I , %): 458 [M] (0.1), 86 [C H ]
rel
6
14
(100)}.
The lower layer contained 14% of allyl(ethyl)-
+
(
(
[
(
(
9
(
hexyl)amine {mass spectrum, m/z (I , %): 169 [M]
rel
+
+
10), 154 [M
Me] (8), 140 [M
Et] (4), 97
+
EtN(CH CH) ] (100), 72 (14)}; 22% of diethyl-
2
2
+
hexyl)amine {mass spectrum, m/z (I , %): 155 [M]
14), 140 [M Me] (100), 111 [M Me Et] (70),
4 [M 2Me Et] (50)}; and 20% of allyl(ethyl)-
hexenyl)silane {mass spectrum, m/z (I , %): 167 [M]
rel
+
+
+
+
rel
+
+
(
36), 152 [M Me] (100), 138 [M Et] (30), 124}.
Reaction of hexylsilane with allylbis(trimethyl-
silyl)amine. Spaier’s catalyst, 3 drops, was added to
a mixture of 1 ml of hexylsilane and 4.9 ml of allyl-
bis(trimethylsilyl)amine. The reaction mixture was
heated for 9 h, during which it warmed up from 65 to
EXPERIMENTAL
1
00 C. No visible changes were noted over the course
The mass spectra were obtained on a Hewlett-
Packard HP-5971A GC MS system at the ionizing
voltage 70 V. Chromatography was performed on a
DB-5 quartz capillary column (25000 0.32 mm)
programmed from 50 to 280 C at a rate 7 deg min ,
carrier gas helium. The UV spectra were measured on
a Perkin Elmer instrument in hexane and THF.
of the process. The reaction mixture was analyzed by
GC MS to find 15.4% of the starting allylbis(tri-
methylsilyl)amine {mass spectrum, m/z (I , %): 201
rel
+
+
[
M] (22), 186 [M
Me] (100), 174 [CH =N(Si
1
2
+
+
+
Me ) ] (20), 73 [SiMe ] (60), 59 [SiHMe ] (8)};
3
2
3
2
3
5.9% of hexyl[ -bis(trimethylsilyl)aminopropyl]-
+
silane, m/z (I , %): 316 [M 1] (0.5), 302 [M
rel
+
+
Me] (2), 228 [M Me SiMe ] (2), 174 [CH =
N(SiMe ) ] (100), 86 [C H ] (14), 73 [SiMe ]
Allylbis(trimethylsilyl)amine. To a mixture of
3 g of allylamine and 150.1 g of hexamethyldisila-
3
2
+
+
+
5
3 2
6
14
3
+
(18), 59 [SiHMe ] (7); 5.4% of the product of double
zane, 2 g of ammonium sulfate was added, and the
reaction mixture was refluxed for 14.5 h at 60 68 C
and then distilled to obtain 101 g of low-boiling frac-
tions and 51.8 g (34%) of allylbis(trimethylsilyl)-
2
addition, mass spectrum, m/z (I , %): 174 [CH =N
rel
2
+
(
SiMe ) ] (100); 3.1% of the product of triple addi-
3 2
+
tion, mass spectrum, m/z: 174 [CH =N(SiMe ) ]
2
3 2
2
0
(100).
amine [bp 42 45 C (6 mm Hg), n 1.4400, purity
D
9
5.1%]. Published data [3]: bp 179 C (741 mm Hg,
2
0
Reaction of hexylsilane with allyl chloride. A
n
1.4363.
D
mixture of 1.6 ml of hexylsilane and 2.0 ml of allyl
chloride was treated with 3 drops of Spaier catalyst.
Gas evolution was observed. The reaction mixture was
boiled for 24 h, and its temperature rose from 60 to
Reaction of hexylsilane with allyldiethylamine.
Spaier’s catalyst, 3 drops, was added to a mixture of
0
.8 ml of hexylsilane and 2.8 ml of allyldiethylamine,
and the resulting mixture was refluxed for 9 h, during
which it warmed up from 88 to 96 C. Gas evolution
was observed, and two almost equal layers formed.
Both layers were analyzed by GC MS. The upper
79 C. The reaction mixture contained 7% of compound
+
V, mass spectrum, m/z (I , %): 191 [M 1] (8), 149
rel
+
+
[C H SiCl] (75), 107 (CH ) SiCl (10), 79 [107
6
13
2 3
+
(CH ) ] (80); 22% of compound VII, mass spectrum,
2
2
+
+
layer contained 1% of ( -diethylaminopropyl)hexyl-
m/z (I , %): 225 [M 1] (15), 183 [M Pr] (50),
rel
+
+
+
silane {mass spectrum, m/z (I , %): 229 [M] (0.5),
141 [PrSiCl ] (100), 113 [MeSiCl2] (36), 99
rel
2
+
+
1
14 [(CH ) NSiEt ] (28), 86 [CH =NEt ] (100)};
[HSiCl ] (14)}; 14.2% of compound IX {mass spec-
2
3
2
2
2
2
+
+
1
6.5% of a complex of hexylsilane with allyldiethyl-
trum, m/z (I , %): 217 [M] (8), 175 [Cl(CH ) SiCl ]
rel 2 3 2
+
+
amine {mass spectrum, m/z (I , %): 229 [M] (5),
(100), 133 [SiCl3] (60)}; 8.4% of compound X
rel
+
+
+
2
00 [M Et} (10), 113 [AllNEt ] (10), 102 [H Si=
{mass spectrum, m/z (I , %): 267 [M 1] (1), 183
2
1
rel
+
+
+
NEt ] (100), 86 [CH =NEt ] (5)}; 13% of allyl-
[C H SiCl ] (10), 149 [C H Cl ] (10), 149
2
2
2
6
13
2
6
13
2
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 76 No. 4 2006

544
BELYAKOVA et al.
+
[
[
C H SiHCl] (40), 141 [PrSiCl ]+ (34), 113
REFERENCES
6
23
2
+
MeSiCl ] (100)}; and 1% of dichloro(hexyl)(propyl)-
silane {mass spectrum, m/z (I , %): 226 [M] (5), 183
Pr] (85), 141 [M
MeSiCl ] (70), 99 [HSiCl ] (32)}.
2
+
1. Storozhenko, P.A., Belyakova, Z.V., Knyazev, S.P.,
Shutova, O.G., Khromykh, N.N., Starikova, O.A., and
Chernyshev, E.A., Russ. J. Gen. Chem., 2006, vol. 76,
no. 2, p. 220.
rel
+
+
[M
C H ] (100), 113
6 13
+
+
[
2
2
ACKNOWLEDGMENTS
2
. Polyakova, A.A. and Khmelnitskii, R.A., Mass-spektry
v organicheskoi khimii (Mass Spectra in Organic
Chemistry), Moscow: Khimiya, 1972, p. 303.
The authors express their gratitude to N.N. Khro-
mykh for measuring the mass spectra.
3
. West, R., J. Organomet. Chem., 1986, vol. 300, no. 2,
p. 327.
The work was financially supported by a grant of
the President of the Russian Federation for young
Russian scientists and leading scientific schools (grant
no. NSh-1811.2003.3).
4. Spaier, J.L., Zimmerman, R., and Webster, J., J. Am.
Chem. Soc., 1956, vol. 78, p. 2278.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 76 No. 4 2006