CARBORANE-(SILOXANE OR SILANE)-UNSATURATED HYDROCARBON BASED POLYMERS

POLYMERES A BASE D'HYDROCARBURES INSATURES DE TYPE CARBORANE-(SILOXANE OU SILANE)

English Abstract

This invention relates to a new class of novel linear inorganic-organic hybrid
polymers of varying molecular weight that are useful
for making high temperature, oxidatively stable thermosets, and these novel
linear polymers are in themselves oxidatively stable at high
temperatures between 600 - 1000 °C. These new materials have repeat
units that contain at least one alkynyl group and at least one bis(silyl
or siloxanyl)carboranyl group within the backbone of these novel linear
polymers. These novel linear polymers can be further polymerized
to form thermosets and ceramics.

Claims

CLAIMS
What is claimed is:
1. An organoboron polymer having a repeating unit consisting
essentially of at least one carboranyl group, one acetylenic
group, and one or more silyl or siloxanyl groups wherein said
repeating unit is represented by the formula:
<IMG>
wherein:
(1) n is an integer from 1 to 12 and u and y are
positive integers;
(2) -(C.ident.C)n-: represents an unconjugated acetylenic
moiety or a conjugated acetylenic moiety when n is
an integer greater than 1;
(3) R1, R2, R3 and R4 represent hydrocarbon or aromatic
moieties;
(4) <IMG> represents said carboranyl group;
and
(5) q and q' are integers from 3 to 16;
(6) x represents an integer greater than or equal to
zero (x.gtoreq.0).
2. The organoboron polymer of claim 1 wherein said
carboranyl group represents a carboranyl group selected from
the group consisting of 1,7-dodecacarboranyl; 1,10-octa-
carboranyl; 1,6-octacarboranyl; 2,4-pentacarboranyl; 1,6-
tetracarboranyl; 9-alkyl-1,7-dodecacarboranyl; 9,10-dialkyl-
1,7-dodecacarboranyl; 2-alkyl-1,10-octacarboranyl; 8-alkyl-
1,6-octacarboranyl; decachloro-1,7-dodecacarboranyl;

octachloro-1,10-octacarboranyl; decafluoro-1,7-
dodecacarboranyl; octafluoro-1,10-octacarboranyl and mixtures
thereof.
3. The organoboron polymer of claim 1 wherein said
carboranyl group represents a closo-dodecacarboranyl group
selected from the group consisting of closo-dodeca-ortho-
carboranyl, closo-dodeca-meta-carboranyl, closo-dodeca-para-
carboranyl and mixtures thereof.
4. The organoboron of claim 1 wherein said R1, said R2, said
R3 and said R4 may be the same or different and wherein each
of said R1, said R2, said R3 and said R4 are independently
selected from the group consisting of a hydrocarbon group
having up to 20 carbon atoms, alkyl, aryl, alkylaryl,
haloalkyl, haloaryl, and mixtures thereof.
5. The organoboron of claim 1 wherein said u, and said y are
integers from 1 to 1000 and said x is an integer from 0 to
1000 and said n is an integer from 1 to 12.
6. The organoboron of claim 1 wherein said u, and said y are
integers from 1 to 500 and said x is an integer from 0 to 500
and said n is an integer from 1 to 10.
7. The organoboron of claim 1 wherein said u, and said y are
integers from 1 to 250 and said x is an integer from 0 to 250
and said n is an integer from 1 to 8.
8. The organoboron of claim 1 wherein said u, and said y are
integers from 1 to 100 and said x is an integer from 0 to 100
and said n is an integer from 1 to 6.
9. The organoboron of claim 1 wherein said n is an integer
from 1 to 3 and said u is an integer from 1 to 10 and said x
is an integer from 0 to 10.
10. The organoboron of claim 1 wherein said n is an integer
from 1 to 2 and said u is an integer from 1 to 10 and said x
is an integer from 0 to 10.
21

11. The organoboron of claim 1 wherein said n equals 1 and
said u is an integer from 1 to 6 and said x is an integer from
0 to 2.
12. A method for preparing a carborane-siloxane-acetylenic
polymer or a carborane-silane-acetylenic polymer having the
formula:
<IMG>
wherein:
(1) R1, R2, R3 and R4 represent hydrocarbon or aromatic
moieties;
(2) -(C.ident.C)n represents an unconjugated acetylenic
moiety or a conjugated acetylenic moiety when n is
greater than 1;
(3) <IMG> represents a carboranyl group selected
from the group consisting of 1,7-dodecacarboranyl;
1,10-octacarboranyl; 1,6-octacarboranyl; 2,4-
pentacarboranyl; 1,6-tetracarboranyl; 9-alkyl-1,7-
dodecacarboranyl; 9,10-dialkyl-1,7-dodecacarboranyl;
2-alkyl-1,10-octacarboranyl; 8-alkyl-1,6-
octacarboranyl; decachloro-1,7-dodecacarboranyl;
octachloro-1,10-octacarboranyl; decafluoro-1,7-
dodecacarboranyl; octafluoro-1,10-octacarboranyl;
closo-dodeca-ortho-carboranyl; closo-dodeca-meta-
carboranyl; closo-dodeca-para-carboranyl and
mixtures thereof;
(4) n is an integer from 1 to 12 and u and y are
positive integers and q and q' are integers from 3
to 16; and
22

(5) x is an integer greater than or equal to zero (x.gtoreq.0);
comprising the step of:
reacting a salt or a Grignard agent having the formula:
M-(C.ident.C)n-M
wherein:
(1) M is selected from the group consisting of Li,
Na, K and MgX' where X' is selected from the
group consisting of F, Cl, Br and I;
(2) -(C.ident.C)n- represents a moiety as previously
indicated; and
(3) n is a positive integer as previously
indicated; with a carborane-siloxane or a
carboran-silane having the formula:
<IMG>
wherein:
(1) Z is selected from the group consisting of
acetyl, F, Cl, Br and I;
(2) R1, R2, R3 and R4 are as previously indicated;
and
(3) x, u, q and q' are integers as previously
indicated.
13. The method of claim 12 wherein Z represents an acetyl
group.
14. The method of claim 12 wherein said R1, said R2, said R3
and said R4 are all methyl groups or all aryl groups or
mixtures thereof.
23

15. The method of claim 12 wherein said u, and said y are
integers from 1 to 250 and said x is an integer from 0 to 250
and said n is an integer from 1 to 12.
16. The method of claim 12 wherein said u, and said y are
integers from 1 to 100 and said x is an integer from 0 to 100
and said n is an integer from 1 to 10.
17. The method of claim 12 wherein said n is an integer from
1 to 6 and said u is an integer from 1 to 10 and said x is an
integer from 0 to 10.
18. The method of claim 12 wherein said n is an integer from
1 to 3 and said u is an integer from 1 to 10 and said x is an
integer from 0 to 10.
19. The method of claim 12 wherein said n is an integer from
1 to 2 and said u is an integer from 1 to 6 and said x is an
integer from 0 to 2.
24

Description

WO 94/12562 PCT/US93/11396
CARBORANE-(SILOXANE OR SILANE)-UNSATURATED POLYMERS
BACKGROUND OF THE INVENTION
FIEhD OF THE INVENTION
The present invention generally relates to an
organoboron polymer containing a carboranyl group, silyl or
siloxanyl groups and alkynyl groups within the backbone of
the organoboron polymer. These bis(silyl or
siloxanyl)carboranyl alkynyl polymers of varying molecular
weight are useful for making further thermosetting polymers
and ceramics and are in themselves oxidatively stable at
high temperatures.
DESCRIPTION OF THE REhATED ART
The recent literature reflects continuing major
research efforts to advance fundamental knowledge in high
temperature material design. See R.J. Wynne and R.W. Rice,
Ceramics V'ra Polymer Pyrolysis 14 liNN . RE V . MAT . 8 C I . 2 9 7 ( 19 8 ~t
) .
In the search for high temperature oxidatively stable
materials considerable attention has been given to polymers
containing boron within the polymer. It has been known that
the addition of a carborane within a siloxane polymer
significantly increases the thermal stability of such
siloxane polymers. Therefore, polymers having the following
general formula have been manufactured:
1

WO 94/12562 i , . ,:- - - _ .:' PCT/US93/11396
C H3 R 3
(Si) ~- ~: ~Sl-~)z
\o/
C H3 (BQHQ~) R ~
where x and y are positive integers, q and q' are integers
from 3 to 16, CBqHq,C is a carboranyl group, and R3 and R4 are
saturated, unsaturated, or substituted hydrocarbons.
Whenever applicable, note that both representations, CBqHq,C
and C~ , are used to represent either the
\o/
(BqHq~)
ortho, meta or para isomers of the respective carboranyl
moieties. Other similar manufactured polymers are polymers
having the general formula:
C H3 CH3
(Sl)-C- C -(Sl-~)z
\o/
~qHq~) ~ 3 Y
or
C H3 CH2CH2CF3 CH3
(Si) ---~- C -(Sl-~)~ ~,~1-~)z
O
C H3 (BqHq~) CH 3 CH3
Y
where y is a positive integer, x is a positive integer '
greater than or equal to 0 (x >_ 0), v is a positive integer
2

:,
WO 94/12562 PCT/US93/11396
i
greater than 0 (v > 0, or v ? 1), and q and q' are integers
from 3 to 16. When q = q' - 10, these polymers are commonly
referred to as DX or Dx+~ F~~, respectively. Another polymer
among this class has the formula:
C H3 CH3 CHzCH
I
(Si)-~C- C -Si-O Si-O
I ~\~~/ 1 I i~
C H3 ~1~1~ ~ 3 C"3
referred to as D2-F~. The thermal properties of these
polymers are given by PETAR DVORNIC ET ~1L. in HIGH
TEMPERATURE SILOyANE EhASTOMERS published by Hutlnig i Wepf
Verlag Basel, New York (1990) on pp. 277 in Fig. 5.7 and on
pp.282 in Fig. 5.12 and by Edward N. Peters in
Poly(dodecacarborane-siloxanes) published in J. MACROMOL. SCI.-RED.
MACROMOh. CHEM., C17(2) on pp. 190-199 lri Figs. 3,4,5,6,7,10
and 12. It is evident from these figures that the
aforementioned polymers lose more than 15-20~ of their
weight when heated, in an oxidative environment, above
600 °C.
Other polymers that have been manufactured have the
following formula:
R1
i~~C CSC
2 0 Rx
where R~ = RZ = Me, or R~ = RZ = Ph, or R' = Ph and R2 = Me
and where y is a positive integer. These polymers also show
3

WO 94/12562 PCT/US93/11396
a weight loss in excess of 15-20% in an inert atmosphere
when heated between 600 - 1000°C. Greater weight loss is
expected in an oxidative atmosphere when heated to the 600 -
1000 ° C range. ee Table II of Maghsoodi et al. in Synthesis and
Study of Silylene-laiaeetylene Pdymers published in 23 MACROMOLECULES
pp. 4486 (1990).
There are very few carborane-siloxane or carborane-
silane polymers that show high temperature stability (weight
loss < 15-20%) in an oxidative environment. Many of the
carborane polymers manufactured are cited in various U.S.
patents. See, for instance, the following commonly assigned
U.S. Pat. Nos.: 4,946,919: 4,269,757; 4,235,987; 4,208,492
4,145,504; 3,661,847; 3,542,730: 3,457,222; and 3,234,288.
While the examples of carborane-silane or carborane-siloxane
polymers cited are not all inclusive, a majority of the
polymers cited exhibit a weight loss greater than 15-20% in
an oxidative environment when heated above 600 °C. There is
an established need for carborane-silane or carborane-
siloxane polymeric materials that show high temperature
stability where weight percentage loss is limited to 20% or
less when heated in excess of 600 °C in an oxidative
environment.
In addition, a majority of the carborane-siloxane or
carborane-silane or alkynyl-silane or alkynyl-siloxane
polymers made by others show elastomeric properties rather
than properties of more rigid polymeric products like
thermosetting polymers or ceramics. Thus, in addition to
4

CA 02150553 2005-04-20
thermal stability, there is also a need for polymers that
behave more as thermosets and ceramics, upon further poly-
merization, and less like elastomeric polymers.
SUN~IARY OF THE INVENTION
The invention thus relates, according to one aspect, to
linear carborane-silane-alkynyl or carborane-siloxane-alkynyl
polymers that show less than 20~ weight loss, in an oxidative
environment, when heated to temperatures between 600-1000°C.
According to another aspect, the invention relates to
linear carborane-silane-alkynyl or carborane-siloxane-alkynyl
polymers which can be readily converted into high temperature
thermosetting polymers or thermosets, upon further polymeriza-
tion, rather than remain as elastomers, between 200-1000°C.
According to yet another aspect, the invention relates to
linear carborane-silane-alkynyl or carborane-siloxane-alkynyl
polymers that have sufficiently low viscosities to readily
fill complex dies for making components therefrom.
As used in this patent specification, including claims,
the terms "hydrocarbon" and "aromatic" have the meanings
assigned by the "Concise Chemical and Technical Dictionary",
Chemical Publishing Co., Inc., (1974). In particular,,"hydro-
carbon" is defined therein as "any of the class of compounds
consisting solely of carbon and hydrogen". The term
"aromatic" is defined therein as "containing one or more
benzene rings".
BREIF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the present invention and
several of the accompanying advantages thereof will be readily
obtained by reference to the following detailed description
5

CA 02150553 2004-05-25
when considered in conjunction with the accompanying drawings,
wherein:
5a

WO 94/12562 . PCT/US93/11396
FIG. 1 is a thermogravimetric analytical (TGA) plot of
weight ~ versus temperature in an oxidizing environment
(air) on the first heating cycle and, subsequently, on the .
second heating cycle in nitrogen for the polymer
poly(butadiyne-1,7-bis(tetramethyldisiloxanyl)-closo-dodeca-
meta-carborane having the formula:
Ri R3 R3 Ri
~.'=_~n ~,~i~u -~o -Sl~z --C -C -~Sl -~)x -(Sl~
R2 R~ ~~Q~) R4 Ra
r
where n = 2 , q = q ° - 10 , a = x = 1, R~ = RZ = R3 = R4 = CH3 ,
and y ~ il (MW ~ 4900).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The following detailed description of the invention is
provided to aid those skilled in the art in practicing the
present invention. However, the following detailed
description of the invention should not be construed to
unduly limit the present invention. Variations and
modifications in the embodiments discussed may be made by
those of ordinary skill in the art without departing from
the scope of the present inventive discovery.
This invention relates to a new class of novel linear
inorganic-organic hybrid polymers of varying molecular
weight having the general formula:
6

1
WO 94/12562 PCT/US93/11396
Ri R3 R3 Ri
~C~~~Sl)u -(~ -$1)z --C --C -~$1 -0)= -~$1~
R2 R4 ~~q~) R4 R2
,uq~1 Y
(
where:
(1) n is an integer from 1 to 12 and a and y are
positive integers:
. (2) ~C ~n represents an unconjugated
acetylenic moiety or a conjugated acetylenic
moiety when n is an integer greater than 1;
(3) R', RZ, R3 and R4 represent hydrocarbon or aromatic
moieties;
(4) C~ represents said carboranyl group;
(BqHq~)
and
(5) q and q' are integers from 3 to 16;
(6) x represents an integer greater than or equal to
zero (x>_0).
The novel linear inorganic-organic hybrid polymers (Z_) with
repeating units containing at least one alkynyl or
acetylenic group and at least one bis(silyl~or
siloxanyl)carboranyl group are designed to take advantage of
the thermo-oxidative stability of inorganics and the
processability of organics. While poly(carborane-siloxane)
7

CA 02150553 2004-05-25
elastomers, silylene-acetylene and silylene-diacetylene
polymers have been reported, polymers (2) containing both the
carboranyl and acetylenic moieties have not been previously
reported.
In the above general formula, the values for R1, R2, R3
and R4 may be the same or different and each of said Ri, R2, R3
and R4 may be independently selected from the group consisting
of a hydrocarbon group having up to 20 carbon atoms, alkyl,
aryl, alkylaryl, haloalkyl, haloaryl and mixtures thereof.
The general chemical scheme for synthesizing these novel
linear polymers (2) is represented by the expemplary synthesis
of (2') given below:
a ci
(9tep 1) ~ Q ~ a-HuLi ----~ ~ _.-.-(C~~a
I \ /
C< C~C
Q a
(step 2) '
T.'-~ -~p ~s --~ -G ~,1-0)s'
z
I i \~I i I
cx, cx, ~,x,~) cx, c~'
~l')
cx, cg, cH, cx,
C~Cr-(Sid --(O -,5i)= -C -C --(Si -0~ --(Si).
0
CHI
where
(1) n = 2, a = x = l, and y is a positive integer;
(2) -..(C~~a - represents a conjugated acetylenic moiety
where n = 2;
(3) R1 - Rz - R3 - R4 - CH3:
(4) ---C--C represents said carboranyl group;
o
8

( ~ . , N ..
O 94/12562 PCT/US93/11396
and
(5) q = q~ - 10;
(6) Z is selected from the group consisting of F, C1,
Br and I:
(7) ~ ~C=C)n Li represents a dilithio salt where
n = 2t and
(8) n-BuLi represents n-butyllithium.
Given the general scheme, step 1 involves forming a salt,
for example, the dilithio salt of butadiyne by reacting 4
equivalents of n-BuLi with hexachlorobutadiene. To form the
polymer (2~), step 2 involves reacting equal molar
concentrations of the dilithiobutadiyne produced in step 1
with compound (1~).
It should be noted that if trichloroethylene is used in
step 1 instead of hexachlorobutadiene, a salt of ethyne or
acetylene is formed in step 1 where n = 1. Consequently, an
ethynyl moiety is incorporated into the polymer produced in
step 2 where n = 1. By using hexachlorobutadiene in step 1,
the salt of butadiyne is formed where n = 2. In turn, a
butadiyne moiety is incorporated into polymer (2~) where n =
2. In order to form a polymer where n = 3, a salt of
hexatriyne needs to be formed in step 1. The synthesis of
the disodium salt of hexatriyne is given in the article by
Bock sad seidl, d Orbital E,,~''ects in Silicon Substituted -rr-Electron
Systems. Part
XII. Some Spectroscopic Properties of Alkyl and Silyl Acetylenes and
Polyacetylenes,
J. CHEM. SOC. (B), 1158 (1968) at pp. 1159. Thus, by
forming the appropriate alkynyl salt, the length of the
9

WO 94/12562 ' PCT/I1S93/11396
. . .
alkynyl moiety, represented by the value of n, incorporated
into the polymer formed in step 2 can be controlled.
Typically, the value of n can be varied from 1 to 12.
Acetylenic derivatives having the general formula H(C~=C)~H
can be readily converted into the dilithio salts by reacting
with n-butyllithium. The respective dilithio salts, with
values of n varying from 1 to 12, can then be incorporated
into the backbone of polymers (2_) as shown in the
aforementioned step 2. The value of n can be varied,
typically, from 1 to 12, more often from 1 to 10 and 1 to 8,
most often from 1 to 6 and, in particular, from 1 to 3 and 1
to 2. Acetylenic derivatives having the general formula
H(C=C)~H can be readily formed by the synthesis given by
Eastmond et al. in Silylation as a Protective Method for Terminal Alkynes in
Oxidative Couplings- A General Synthesis of the Parent Polyynes, 28
TETRAHEDRON
4601 (1972).
Furthermore, a variety of compounds can be produced
that have structures similar to that of compound (1') shown
in step 1. One variation includes replacing the methyl
groups attached to the Si with other hydrocarbon or aromatic
moieties. Typical reactions synthesizing disubstituted
dichloro silanes of varying size (varying values of u) and
having different R groups are known in the art:
I + 2u M' ~ ( + 2M'C1
Cl Si-C1 Cl (Sid-C1
R2

WO 94112562 ? ~ PCT/US93/11396
where M' is a group 1 metal or alloy. The above reaction is
cited by ZELDIN ET AL. (EDITORS) in INORGANIC AND
ORGANOMETALLIC POLYMERS, published by American Chemical
Society, llashington, DC (1988) at ~4 and 90. The value of a
can be varied, typically, from 1 to 1000, more often from 1
to 500 and 1 to 250, most often from 1 to 100 and 1 to 10,
and, in particular, from 1 to 6. Another variation includes
controlling the values of x in addition to that of u.
Synthesis of a variation of compound (1~) where a =1
and x = 0 and Z = C1 is given by Papetti et al . in A New Series
of Organoboranes. Yl. The Synthesis and Reactions of Some Silyl Neocarboranes,
3
INORG. CBEM. 148 (1964) at 1449 under the caption ~~C,C~-
Bis(methyldichlorosilyl)neocarborane (IV).~~ The synthesis
of compound (1~) where a = 1 and x = 1 and Z = C1 is given
by Papetti et al . in A New Series of Organoboranes. Y11. The Preparation of
Poly-m-carboranylenesiloxanes, 4 JOURNAL OF POLYMER SCIENCE: PART A-
1, 1623 (1966) at 1630 under the caption ~~Compound (VII).~~
Synthesis of a variation of compound (1~) where a =1 and x =
2 and Z = C1 is given by Scott et al. in Icosahedral Carboranes.
2 0 X1! Monomeric Carboranylenesiloxanes, 9 INORG . CBEM . 2 5 9 7 ( 19 7 0 )
at
2599 under the caption ~~1,7-Bis(5-
chlorohesamethyltrisiloxanyl)-m-carboraae (IV).~~
While leaving a = 1, the value of x can be varied,
typically, from 0 to 1000, more often from 0 to 500 and 0 to
250, most often from 0 to 10, and, in particular, from 0 to
2 by the following proposed reaction scheme:
11

WO 94/12562 ~ - PCT/US93111396
Ri Ri
Cl-Si--(O--Si~,~
Rs Rs
Ri R1 R~ Rt
1 O Cl-(Sid -(O -Si)i -C -C --(Si -O)i --(Sid Ct
~ \a
Ri Rs ~~q~) Rs Rz
HZO
Et20
Ri RI R1 Ri
~si~y ~o -Sl~z+w+2 ~ ~ '~'Sl -~~z+~,+2 -~'Sl~u
RZ R2 ~~q~~ R2 R2
where x and w are integers greater than or equal to 0 (x>_0;
w>_0) and a is a postive integer.
Following the scheme in the aforementioned steps 1 and
2, the novel linear polymers (2) can be formed by reacting a
salt of an alkyne or a respective Grignard reagent with
compound (1):
12

WO 94/12562 PCT/US93/11396
(step 2)
M -(C=C)n M
R1 Rs Rs R'1
Z-~$1~ -~~ -$1~= -C --C -~$1 -~~x -~Sl)u
R2 R4 ,LQH4i) R~ R2
(1)
R1 R3 R3 R1
(C.C~n ($i)u -(p -$1~= --C --C -~$1-~~z -($i~u
2o R2 R~ (BqHq~) R4 R2
(~)
where:
(1) n is an integer from 1 to 12 and a and y are
postive integers;
13

WO 94/12562 , PCT/US93/11396
. . i
( 2 ) - (C 'C)n -' represents an unconj ugated
acetylenic moiety or a conjugated acetylenic
moiety when n is an integer greater than 1;
( 3 ) R' , R2, R3 and R4 represent hydrocarbon or aromatic
moieties;
(4) --C~ represents said carboranyl group:
io
(BQHQ~)
and
(5) q and q' are integers from 3 to 16;
(6) Z is selected from the group consisting of F, C1,
Br and I;
( 7 ) M -(C=C)- M represents a salt of an alkyne or
n
the respective Grignard reagent where M is
selected from the group consisting of Li, Na, K
and MgX' where X' is selected from the group
consisting of F, C1, Br and I: and
(8) x represents an integer greater than or equal to
zero (x>_o).
These novel linear polymers (2_) exhibit sufficiently
low viscosities either at room temperature or at their
respective melting points (mp ~ 200 °C) to readily fill
complex dies or shapes for forming parts therefrom. In
addition, these polymers (2_) can be further polymerized into
14

WO 94112562 PCT/US93/11396
_.
thermosets and ceramics that form rigid shapes which are
oxidatively stable at high temperatures above 600 °C.
The following examples detail the synthesis of polymer
(2') and related polymer (2 "), polymer (~'!) having the
structure:
CH3 CH3 CH3 CH3
~C-(sl~ -(o -sl)z -C --C -(Sl -~)z -($1)0
C H 3 CH 3 (BqHQ~) CH 3 CH 3
Y
where:
(1) a = 1 and x = 0, q = q' - 10 and y is a positive
integer.
EXAMPLE 1
sYNTHE8I8 OF POLY(BUTADIYNE-1,7-BIS(TBTRAMETHYLDIBILOBANYL)-
LO80-DODECA-META-CARBORANE)(2'):
CH3 CH3 CH3 CH3
C=-C~-(Si) -(O -Si) -C -C -(Si -O) -(Si)
\o/
C H 3 CH 3 (Bi~Hi~ CH 3 ~ 3
(2' )
Dilithiobutadiyne was prepared by the method of Ijadi-
Magshoodi and Barton. See 8. Ijadi-Magshoodi, Y. Pang, and
T . J . Barton, E,~cient, "One-Pot" Synthesis of Silylene Acetylene and
Disilylene-

WO 94/12562 ~ ~ PCT/C1S93/11396
Acetylene Preceramic Polymers from Trichloroethylene, 28 J. POLYM. 8CI. ,
Pl~RT A: POLYM.~CHEM. 955 (1990). According to Magshoodi et
al., 4 equivalents of n-BuLi in THF are cooled to -78 °C and
hexachlorobutadiene is slowly added. After warming to room
temperature, the dilithiobutadiyne is not isolated before
use. In a typical synthesis, N-BuLi (34.2m1, 85.5 mmol) in
12.0 ml THF was cooled to -78 °C. Hexachlorobutadiene
(5.58g, 21.4 mmol) in 2.0 ml THF was added dropwise by
cannula. The reaction was allowed to warm to room
temperature and stirred for 2 hrs. Then
dilithiobutadiyne/THF was again cooled to -78 °C~. To this,
an equal-molar amount of the 1,7-bis
(chlorotetramethyldisiloxanyl)-closo-dodeca-meta-carborane
(1~) (10.22g, 21.4mmo1) in 4.0 ml THF was added dropwise by
cannula. The temperature of the reaction mixture was allowed
to slowly rise to ambient temperature and stirred overnight.
A white solid (LiCl) was filtered off and the solvent
removed by evaporation at reduced pressure leaving (2~).
The polymer (2~) was dissolved in ether and dried over
sodium sulfate. After filtration through Celite, the ether
. was evaporated at reduced pressure, leaving the dark-brown
viscous polymer (2~). A 97 % yield (9.5g) was obtained after
drying in vacuo. Gel-permeation chromatography (GPC)
indicated the presence of low molecular weight species
(MW " 500) as well as higher average molecular weight
polymers (MW " 4900). Drying under vacuum at 150 °C removed
lower-weight volatiles giving a 90 % overall yield. Major
16

WO 94112562 ~ PCT/US93/1I396
IR peaks (cm-~): 2963 (C-H stretch); 2600 (B-H stretch); 2175
(C=C stretch); 1260 (Si-CH3 deformation).
BgAMPLE 2
8YNTHE8I8 OF POLY(ETHYN-1,7-BI8(DIMETHYLBILYL)-CLO80-DODECA-
METH-CARBORANE (2~~):
CH3 CH3
C ~si~ -C (Sl~
C H 3 ~1~1~ ~ 3
Dilithioacetylene has the formula:
Li-C---C-Li
and it is prepared by the method of Ijadi-Magshoodi et al.
ee 8. Ijadi-Magshoodi, Y. Pang, and T.J. Barton 28 J. POLYM.
BCI., PART A: POLYM. CHEM. 955 (1990). According to Ijadi-
Magshoodi method for preparing dilithioacetylene, 3
equivalents of n-BuLi in THF are cooled to -78°C and
trichloroethylene is slowly added. After warming to room
temperature, the dilithioacetylene is not isolated before
use. In a typical synthesis, rz-BuLi (21.6 ml, 54.0 mmol) in
10.0 ml THF was cooled to -78°C under an argon atmosphere.
Trichloroethylene (1.6 ml, 18.0 mmol) in 5.0 ml THF was
added dropwise. The reaction was permitted to warm to room
temperature and stirred for 14 hrs.
17

~~~4~5~
WO 94/12562 ", w PCT/LTS93/11396
. _ , .. ..
Compound (1"~) is synthesized according to the method
of Papetti & Heying. Bee 8. Papetti et al. 3 INORG CHEM
1448 (1961). The structure of compound (1~~) is given
below:
sl -t --~ sl
C H 3 ~1~1~ ~ 3
(l~~)
According to the method of Papetti et al., a 100m1 round
bottom 3-neck flask was fitted with an addition funnel and
septa, flushed with argon, and flamed. The reaction was
carried out under an inert atmosphere (argon). Butyllithium
(18.0 ml/ 2.5M in hexanes, 44.9 mmol) was cooled to -78°C.
Meta-carborane (2.5902 g, 18.0 mmol) in 10 ml THF was added
dropwise. A white solid (dilithiocarborane) formed and the
reaction was allowed to warm to ambient temperature. After
cooling the reaction mixture back to -78°C,
dichlorodimethylsilane (5.5 ml, 43.5 mmol) was added
dropwise. The product (1~,) in solution was not isolated.
To form the product (2~~), the dilithioacetylene is
reacted with (ion). The dilithioacetylene in THF was cooled
back to -78°C. To this, (1~~), as previously prepared, was
added dropwise (18.0 mmol, 5.93 g) and allowed to warm to
ambient temperature and stirred overnight. The solvent was
18

WO 94112562 PCT/US93/11396
removed by evaporation at reduced pressure leaving behind
the dark brown polymer (2~~).
19