Silazanes of boronꢀsubstituted oꢀcarboranes
Russ.Chem.Bull., Int.Ed., Vol. 63, No. 10, October, 2014
2341
Table 1. Elemental analysis and spectral data for silazanes 2, 4, 6—8, and 10
Silazana
Molecular
formula
Found
Calculated
Molecular weight
Found*
IR,
(
%)
–
1
/cm
B—H
2610
Calculated
C
H
B
N
Si
SiNSi
Ccarb—H
2
4
6
7
8
C H B NSi
26.83
8.72
8.81
7.99
8.32
7.00
7.31
9.78
9.32
9.52
9.63
9.45
9.63
47.93
48.49
48.00
48.28
51.10
50.63
35.63
35.72
29.10
28.70
24.30
24.02
3.00
3.14
9.00
9.37
12.11
12.59
12.00
12.54
13.10
13.15
18.00
18.35
22.19
22.37
24.38
24.96
440
445
450
448
1300
1280
300
303
370
377
450
450
930—945
3090
3090
3090
3090
3090
3090
1
0
39 20
2
2
2
6.94
22.00
1.45
17.11
6.87
32.00
1.75
31.02
1.88
31.89
2.03
C H B N Si
940—950
950—960
945
2610
2610
2610
2610
2610
8
37 20
3
2
C H B N Si
6
10.30
12.02
4.28
4.62
7.00
7.43
9.35
9.33
18
93 60 11
1
C H B NSi
2
8
25 10
3
C H B N Si
945
1
0
36 10
2
3
4
3
1
0
C H B N Si
945
1
2
43 10
3
3
*
Ebullioscopy in toluene.
toluene, and other solvents. Some characteristics of these
products are given in Table 1.
Thus, upon ammonolysis of boronꢀsubstituted chloroꢀ
silylmethyl oꢀcarborane derivatives and their coammonoꢀ
lysis with trimethylchlorosilane, new carboranylmethylꢀ
pound 2 (12.2 g, 91.5%). After recrystallization from heptane,
the melting point was 150—152 C.
1
,3ꢀDiaminoꢀ1,3ꢀdi(oꢀcaboranylꢀ9ꢀmethyl)ꢀ1,3ꢀdimethylꢀ
disilazane (4) was obtained according to the analogous procedure
from carboranylmethyl(methyl)dichlorosilane (3) (16.24 g,
0
.059 mol) in yield of 11 g (82%) as a colorless oily liquid.
(
organo)silazanes with terminal aminosilane or trimethylꢀ
Oligo(oꢀcaboranylꢀ9ꢀmethyl)silsesquiazane (6) was obtainꢀ
silyl groups were obtained. It was established that, during
ammonolysis, the bulky carboranylmethyl groups
hinder the intermolecular condensation of intermediate
products with aminosilane groups and favor the formaꢀ
tion of lowꢀmolecularꢀweight organosilazanes not only
from monoꢀ and dichlorosilanes, but also from carborꢀ
anylmethyltrichlorosilane. The possibility of the
Ccarborane—H groups having the acidic nature to be inꢀ
volved in the formation of oligo(carboranylmethyl)ꢀ
silsesquiazane (6) and its roomꢀtemperature structuring
products was found.
ed according to the analogous procedure from (carboranꢀ
ylmethyl)trichlorosilane (17.5 g, 0.059 mol) in yield of 10.4 g
(81%) as a white amorphous powder with a softening point of
140—150 C.
1
ꢀ(oꢀCaboranylꢀ9ꢀmethyl)ꢀ1,1,3,3,3ꢀpentamethyldisilazane
(
7). A flask equipped with a reflux condenser, stirrer, thermoꢀ
meter, and bubbler for NH supply and cooled with a acetone—dry
3
ice mixture was loaded with carboranylmethyl(dimethyl)chloroꢀ
silane (1) (15 g, 0.059 mol), trimethylchlorosilane (6.5 g,
0
.059 mol), and dry diethyl ether (160 mL) and cooled to –50 C.
NH gas was passed with stirring through the mixture so that the
3
reaction temperature was not higher than –40 C. At pH 10, the
NH supply was stopped, the reaction mixture was warmed to
3
room temperature, and NH Cl was separated on a glass filter.
4
Experimental
Distillation at 145—146 C (2 Torr) yielded compound 7 (4.53 g,
2
5%) as a heavyꢀbodied liquid with nD20 = 1.500. Heptane
(
30 mL) was added to the residue and the resulted solution
Boronꢀcontaining chlorosilylmethyl derivatives of oꢀcarboꢀ
rane were prepared from chloromethyl(organo)chlorosilanes and
oꢀcarborane according to a known procedure.3
was cooled to –20 C to precipitate crystals of compound 2
(2.4 g, 18%).
1,1,1,3,5,5,5ꢀHeptamethylꢀ3ꢀ(oꢀcaboranylꢀ9ꢀmethyl)triꢀ
silazane (8) was prepared according to the analogous proceꢀ
dure from carboranylmethyl(methyl)dichlorosilane (3)
(16.26 g, 0.059 mol) and trimethylchlorosilane (8.68 g,
0.059 mol). After distillation at 160—161 C (2 Torr), compound
8 (4.4 g, 19.5 %) was obtained as a colorless viscous liquid with
1
,3ꢀDi(oꢀcaboranylꢀ9ꢀmethyl)ꢀ1,1,3,3ꢀtetramethyldisilazane
(
2). A flask equipped with a reflux condenser, stirrer, thermoꢀ
meter, and bubbler for NH3 supply and cooled with an aceꢀ
tone—dry ice mixture was loaded with carboranylmethyl(diꢀ
methyl)chlorosilane (1) (15 g, 0.059 mol) in dry diethyl ether
2
0
(
100 mL) and cooled to –50 C. NH gas was passed with stirring
nD = 1.5135.
Tris(trimethylsilylamino)ꢀoꢀcaboranylꢀ9ꢀmethylsilane (10)
3
through the mixture so that the reaction temperature was not
higher than –30 C. At pH 10, NH supply was stopped, the
was prepared according to the analogous procedure from (carbꢀ
oranylmethyl)trichlorosilane (5) (17.5 g, 0.059 mol) and triꢀ
methylchlorosilane (10.86 g, 0.059 mol). After distillation at
175—176 C (2 Torr), compound 10 (1.62 g, 6%) was obtained as
a colorless viscous liquid with nD20 = 14934.
3
reaction mixture was warmed to room temperature, NH Cl was
4
separated on a glass filter, and diethyl ether was evaporated.
Heptane (30 mL) was added to the residue and the resulted
solution was cooled to –20 C to precipitate crystals of comꢀ