Facile synthesis of 1,3-dichlorotetra-organodisilazanes

Article abstract of DOI:10.1081/SCC-100104826

A new 1,3-dichlorodisilazane, 1,3-dichloro-1,3-dimethyl-1,3-divinyldisilazane (DMDV), was prepared from the trans-silylation reaction of hexamethyldisilazane (MM^N) and methylvinyldichlorosilane. The reactions between MM^N and other di

Full text of DOI:10.1081/SCC-100104826

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FACILE SYNTHESIS OF 1,3-
DICHLOROTETRAORGANODISILAZANES
a
a
a
a
b
Cai-Hong Xu , Zhi-Min Zheng , Yong-Ming Li , Zhi-Jie Zhang & Ze-Min Xie
a
Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences ,
Beijing, 100080, China
b
Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences ,
Beijing, 100080, China
Published online: 09 Nov 2006.
To cite this article: Cai-Hong Xu , Zhi-Min Zheng , Yong-Ming Li , Zhi-Jie Zhang & Ze-Min Xie (2001) FACILE SYNTHESIS OF
1,3-DICHLOROTETRAORGANODISILAZANES, Synthetic Communications: An International Journal for Rapid Communication
of Synthetic Organic Chemistry, 31:15, 2271-2275, DOI: 10.1081/SCC-100104826
To link to this article: http://dx.doi.org/10.1081/SCC-100104826
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SYNTHETIC COMMUNICATIONS, 31(15), 2271–2275 (2001)
FACILE SYNTHESIS OF
1,3-DICHLOROTETRA-
ORGANODISILAZANES
Cai-Hong Xu, Zhi-Min Zheng, Yong-Ming Li,
Zhi-Jie Zhang, andZe-Min Xie *
Center for Molecular Science, Institute of Chemistry,
Chinese Academy of Sciences, Beijing, 100080, China
ABSTRACT
A new 1,3-dichlorodisilazane, 1,3-dichloro-1,3-dimethyl-1,3-
divinyldisilazane (DMDV), was prepared from the trans-sily-
N
lation reaction of hexamethyldisilazane (MM ) and methyl-
N
vinyldichlorosilane. The reactions between MM and other
dichlorosilanes, R SiCl (R ¼ Me, Ph) in the absence of cata-
2
2
lyst were also investigated, and the expected, 1,3-dichlorosila-
zanes, (ClSiMe ) NH and (ClSiPh ) NH were obtained,
respectively.
2
2
2 2
Silicon-based non-oxide ceramics, such as silicon nitride and silicon
carbide ceramic materials, have attracted continuous interest for many
1
–3
years due to their excellent properties in extreme conditions.
4
Since the
pioneering work of Verbeek in the mid 1970s, intense research over the
past 25 years has focused on the elaboration of Si N , SiC or Si/C/N-based
3
4
materials from pyrolysis of organosilicon precursors. Compared with tradi-
tional technologies, the method from precursors offer many fabrication
*
Corresponding author.
2
271
Copyright & 2001 by Marcel Dekker, Inc.
www.dekker.com

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2
272
XU ET AL.
advantages in processing, especially in producing complex ceramic parts and
composites. Properties of the final ceramic materials are strongly dependent
on the structures and the chemical composition of precursors. According to
1
,5,6
the literatures,
the ideal preceramic polymer should contain rings or cages
structure in molecule to decrease the polymer skeleton degradation; have
latent chemical reactivity to obtain thermosetting or curing properties; and
possess appropriate processibilities to apply the polymer in the desired shape
before the pyrolysis process. In an attempt to prepare polysilazane that
according with these rules, recently, we designed a new route to synthesize
a class of new polysilazanes containing linear-cyclic structure as well as reac-
7
,8
tive groups. It was shown that these polysilazanes could be thermally or
catalyzed cross-linked and then pyrolysized to Si/C/N ceramics. In the new
route, 1,3-dichlorodisilazanes were used as starting materials. In this paper,
we report a facile synthesis route to 1,3-dichlorodisilazanes in the absence
of any catalyst. Via the method, a new 1,3-dichlorodisilazane, 1,3-di-
chloro-1,3-dimethyl-1,3-divinyl-disilazane, (ClSiMeVi) NH, was obtained,
2
which has not been synthesized and characterized before. In addition, the
un-catalyzed reactions of hexamethyldisilazane with dimethyldichlorosilane
and diphenyldichlorosilane were studied and the expected products,
1,3-dichloro-1,1,3,3-tetramethyldisilazane and 1,3-dichloro-1,1,3,3-tetra-
phenyldisilazane were synthesized, respectively.
In contrast with the alkyl-, aryl-substituted disilazanes, symmetrical
j
j
j
1
,3-dichlorodisilazanes, Cl ÀÀ Si ÀÀ N ÀÀ Si ÀÀ Cl, were not obtained via con-
j
j
j
densation of Si-Cl bond of dichlorosilanes with ammonia, which generally
prepared from equilibrium reaction between cyclosilazanes and
9
diorganodichlorosilanes. Silbiger first reported reaction of hexamethyldisi-
lazane with dimethyldichlorosilane in the presence of AlCl as the catalyst
3
and 1,3-dichloro-1,1,3,3-tetramethyldisilazane were obtained. Bacque and
´
1
Pillot also studied trans-silylation reaction between hexamethyldisilazane
0
and dimethyldichlorosilane, results shown that no reaction occurred without
n
catalyst. However, in the presence of ( Bu N)F, the reaction took place
smoothly.
4
As important starting materials in the preparation of polysilazanes
containing linear-cyclic structure, 1,3-dichlorodisilazanes were re-investi-
gated in our work. We first examined the reaction between (Me Si) NH
3
2
and MeViSiCl2 without a catalyst. As expected, (ClMeViSi) NH
2
was obtained in good yield after heating under reflux for a few hours. It
is necessary to indicate that the another product, Me SiCl must be
3
continuously distilled off during the reaction.
refl:
Me Si) NH þ 2MeViSiCl À! (ClMeViSi) NH þ 2Me SiCl
(
(1)
3
2
2
2
3

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1
,3-DICHLOROTETRAORGANODISILAZANES
2273
Then we studied the reaction of (Me Si) NH and Ph SiCl . To the best of
3
2
2
2
our knowledge, there have been no available reports on this reaction. With
the 1:2 ratios of (Me Si) NH to Ph SiCl , no catalyst, the reaction occurred
smoothly, and completed after 17 hours. A new synthetic way with good
3
2
2
2
1
1
yields to (ClPh Si) NH was given in our previous work. However, the
2
2
reaction needs long heated time (50 h) and a large excess of Ph SiCl ,
2
2
furthermore, another reactant, cyclosilazane, is much more expensive than
Me Si) NH.
(
3
2
Based on the above reactions, we assumed that it might be feasible
to prepare (ClMe Si) NH via this method. Thus, the reaction between
2
2
(
with literature,
Me Si) NH and Me SiCl without catalyst was re-examined. In contrast
3 2 2 2
9
,10
the reaction occurred under the condition that we
adopted. There were resonance of the expected (ClMe Si) NH and
2
2
2
Me SiCl in Si NMR spectra of the reaction mixture.
9
3
1
0
Bacque
´
suggested that for the redistribution reaction between
Me Si) NH and HRSiCl , the first trimethylsilyl-group exchange may be
(
reversible. The analogous conclusion also can be inferred for the reaction of
3
2
2
0
(
Me Si) NH and RR SiCl .
3
2
2
0
0
(
Me Si) NH þ RR SiCl > ClRR Si-NH-SiMe þ Me SiCl
(2)
(3)
3
2
2
3
3
0
0
ClRR Si-NH-SiMe þ RR SiCl ?
3
2
0
0
ClRR SiNHSiRR Cl þ Me SiCl
3
With Me SiCl distilled off, the equilibrium as depicted in eqn. (2) could
3
0
be apt to transfer to right, which lead to more intermediate ClRR Si-NH-
SiMe . Then the trimethylsilyl group of the intermediate was substituted by
3
1
another mixed-silicon ligand, -SiRR Cl, and the product (ClRR Si) NH
0
0
0
2
was gained, which is more stable thermodynamically.
EXPERIMENTAL
IR spectroscopy was recorded on FT-IR spectrophotometer, PE-80.
1
29
H-NMR and Si-NMR were performed on Unity 200 MHz, USA.
Element Analysis was measured with Heraeus CHN-RAPID, systems, Inc
West Germany). Toluene and n-hexane were commercially available and of
(
analytical purities, which were dried over sodium under reflux and distilled
before used. Methylvinyldichlorosilane, dimethyldichlorosilane, diphenyl-
dichlorosilane and hexamethyldisilazane were distilled and reserved in dry
container before used. The samples were protected with dry nitrogen during
1
29
the process of measurements. CDCl used in H-NMR and Si-NMR was
3

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2
274
XU ET AL.
dried with CaO. Tetramethylsilane (TMS) was used as external reference for
2
Si-NMR.
9
General Procedure
0
RR SiCl (2 mol) and (Me Si) NH (1 mol) were mixed in a three-necked
2
3
2
flask equipped with a stir-bar, a N gas inlet tube, a thermometer and a
2
fractionating column, which connected with a distillation apparatus. The
mixture was heated under reflux, and at the same time, the by-product
Me SiCl was removed by distillation. When the reaction was completed, for
3
0
0
R ¼ Me, R ¼ Vi or R ¼ R ¼ Me, the fractionating column was then replaced
by a short Vigreux column connected to vacuum line via a receiver and a
0
liquid nitrogen trap, as the mixture was heated, (ClRR Si) NH were collected
2
0
in the receiver. For R ¼ R ¼ C H , the precipitated crystals were filtered off
6
5
and washed with hexane, crude (ClPh Si) NH were obtained.
2
2
1
,3-Dichloro-1,3-dimethyl-1,3-divinyldisilazane DMDV. According to
the general procedure, a mixture of (Me Si) NH (35.9 g, 0.22 mol) and
3
2
MeViSiCl (62.5 g, 0.44 mol) was heated under reflux accompanied with
2
Me SiCl distilled off. The reaction was completed after 20 hours. As the
3
mixture was heated, DMDV was condensed in the receiver (35.5 g, 70%).
1
H NMR (CDCl ), d (ppm): 0.57 (s, 6H, CH ); 1.7 (broad, m, 1H, NH);
3
3
2
9
5
.9–6.2 (s, 6H, CHCH2). Si NMR (CDCl ), d (ppm): 1.20 (s, NSiMeViCl).
3
Anal. Cald. for C H Cl NSi : C, 31.86; H, 5.75; N, 6.19; Cl, 31.42. Found:
6
13
2
2
C, 31.78; H, 5.76; N, 6.19; Cl, 31.22%.
,3-Dichloro-1,1,3,3-tetraphenyldisilazane DCTPS. According to the
general procedure, a mixture of (Me Si) NH (19.9 g, 0.12 mol) and Ph SiCl
2
1
3
2
2
(
62.5 g, 0.24 mol) was heated under reflux accompanied Me SiCl distilled
3
off. The reaction was completed after 17 hours. Then the precipitated crys-
tals were filtered off at room temperature and washed with hexane. The
crude product was recrystallized from the mixed solvent of hexane and
toluene to give 43.5 g (78%) of pure DCTPS as white crystals.
ꢀ
1
m.p. 117.1 C. H-NMR (CDCl ), d (ppm): 2.5 (s, 1H, NH); 7.2–7.6 (m,
3
2
9
2
0H, (C H ) ). Si-NMR (CDCl ), d (ppm): À7.5 (s, NSi(C H ) Cl).
6
5 4
3
6
5 2
Anal. Cald. for C H Si NCl : C, 64.00; H, 4.67; N, 3.11; Cl, 15.78.
24 21 2 2
Found: C, 63.70; H, 4.56; N, 2.91; Cl, 15.49%.
,3-Dichloro-1,1,3,3-tetramethyldisilazane TMDS. According to the
general procedure, a mixture of (Me Si) NH (32.2 g, 0.20 mol) and
1
3
2
Me SiCl (51.6 g, 0.40 mol) was heated under reflux accompanied with
2
2
Me SiCl distilled off. The reaction was completed after 20 hours. As the
3
mixture was heated, TMDS was condensed in the receiver (19.8 g, 49%).
1
H NMR (CDCl ), d (ppm): 0.27 (s, 12H, CH ); 1.2 (broad, m, 1H, NH).
3
3

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1
,3-DICHLOROTETRAORGANODISILAZANES
2275
2
9
Si NMR (CDCl ), d (ppm): 13.70 (s, NSiMe Cl). Anal. Cald. for
3
2
C H Cl NSi : C, 23.76; H, 6.44; N, 6.93; Cl, 35.15. Found: C, 23.58; H,
6.36; N, 6.79; Cl, 34.92%.
4
13
2
2
REFERENCES
1
2
. Birot, M.; Pillot, J.-P.; Dunogues, J. Chem. Rev. 1995, 95, 1443.
. Brochon, C.; Duguet, E.; Schappacher, M. et al. Polym. Prepr. 1996,
7, 807.
3
3. Song, Y.C.; Zhao, Y.; Feng, C.X. et al. J. Mater. Sci. 1994, 29, 5745.
4. Verbeek, W.; Winter, G. 1974, German Patent 2,236,078.
5. Blum, Y.D.; Schwartz, K.B.; Laine, R.M. J. Mater. Sci. 1989, 24, 1707.
6. Xie, Z.M.; Li, G.L. Polymer Bulletin (Chinese), 1995, 3, 138.
7. Xie, Z.M.; Xu, C.H.; Zhou, N.; CN 99123986.5, applied in 1999.
8. Xu, C.H.; Zheng, Z.M.; Li, Y.M.; Xie, Z.M. J. Mater. Sci. submitted.
9. Silbiger, J.; Fuchs, J. Inorg. Chem. 1965, 4, 1371.
1
1
0. Bacque
, E.; Pillot, J.-P.; Birot, M.; Dunogues, J.; Bourgeois, G.;
´ ´
Petraud, M. J. Organometal. Chem. 1994, 481, 167.
´
1. Zhou, N.; Zhang, Z.J.; Xu, C.H.; Xie, Z.M.; Hua Xue Tong Bao 2000,
in press.
Received in Japan July 25, 2000

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