Molecules 2016, 21, 1079
19 of 25
2,5,9,12-Tetrakis(triisopropylsilyl)-2,5,9,12-tetrakis(triisopropylsilyl)tetracosamethyl-tri-deca-silane (12). Same
procedure as described for 11 using: 10 (0.152 mmol) and 1,3-dichlorhexamethyltrisilane (40 mg,
0.161 mmol). After 5 h same work up procedure as for
5 yielded 12 colorless oil (271 mg, 71%,
1
mixture of both isomers). H-NMR (
δ
in ppm): 1.10–1.39 (m, 50H), 0.48 (s, 42H), 0.32 (s, 18H), 0.30
9.1 (Me3Si), 9.2 (Me3Si),
24.2 (Me2Si), 28.1 (Me2Si),
33.0 (Me2Si), 108.3 (Siq), 119.7
104 M−1 cm−1), λ2 = 267 nm
(s, 36H). 29Si-NMR (
δ
in ppm): 16.0 (iPr3Si), 14.1 (iPr3Si), 13.6 (iPr3Si),
9.4 (Me3Si), 9.4 (Me3Si), 10.7 (Me3Si), 23.7 (Me2Si),
32,7 (Me2Si), 32.8 (Me2Si), 33.0 (Me2Si),
−
−
−
9.3 (Me3Si),
32.0 (Me2Si),
−
−
−
−
−
−
−
−
−
−
−
−
−
(Siq),
−
124.9 (Siq), 125.1 (Siq). UV absorption: λ1 = 219 nm (ε1 = 2.8
×
·
(ε2 = 4.6 × 104 M−1·cm−1), λ3 = 283 nm (shoulder), λ4 = 307 nm (shoulder).
2,5,10,13-Tetrakis(triisopropylsilyl)-2,5,10,13-tetrakis(triisopropylsilyl)hexacosamethyl-tetra-decasilane (13).
Same procedure as described for 11 using: 10 (0.152 mmol) and 1,4-dichlorooctamethyltetrasilane
(51 mg, 0.167 mmol). After 5 h same work up procedure as for
5
yielded 13 as a colorless oil (211 mg,
1
81%, mixture of both isomers). H-NMR (
δ
in ppm): 1.12–1.37 (m, 50H), 0.48 (s, 48H), 0.32 (s, 18H), 0.30
9.1 (Me3Si), 9.2
29.2 (Me2Si), 29.5
119.3 (Siq), 119.4
(s, 36H). 29Si-NMR (
δ
in ppm): 16.9 (iPr3Si), 14.2 (iPr3Si), 14.1 (iPr3Si), 11.1 (iPr3Si),
9.3 (Me3Si), 23.1 (Me2Si), 24.1 (Me2Si), 28.8 (Me2Si),
31.3 (Me2Si), 32.0 (Me2Si), 104.6 (Siq), 106.9 (Siq),
104 M−1
−
−
(Me3Si),
(Me2Si),
−
9.3 (Me3Si),
29.6 (Me2Si),
−
−
−
−
−
−
−
−
−
−
−
−
−
(Siq). UV absorption: λ1 = 220 nm (ε1 = 2.9
×
·
cm−1), λ2 = 268 nm (ε2 = 4.5 × 104 M−1·cm−1
),
λ3 = 293 nm (ε2 = 3.8 × 104 M−1·cm−1), λ4 = 311 nm (shoulder).
2,5,8,11-Tetrakis(trimethylsilyl)icosamethyldodecasilan (14). Same procedure as described for
5 using
2,5-bis(trimethylsilyl)undecamethylhexasilanyl-2-potassium (1.63 mmol) (prepared from: 2,2,5-tris
(trimethylsilyl)undecamethylhexasilane (900 mg, 01.63 mmol), KOtBu (160 mg, 1.71 mmol) in THF
(10 mL)) and 1,2-dichlorotetramethyldisilane (0.854 mmol, 16 mg). After 5 h same work up procedure
as for
1H-NMR (
(s, 36H). 29Si-NMR (
5
yielded colorless crystalline 14 (830 mg, 95%) after recrystallization using pentane/acetone.
δ
in ppm, CDCl3): 0.46 (s, 12H), 0.42 (s, 12H), 0.35 (s, 12H), 0.30 (s, 36H), 0.28 (s, 6H), 0.20
δ
in ppm, CDCl3):
−
9.2 (Me3SiSiMe),
−
11.7 (Me3Si),
−
28.2 (SiMe2),
−
31.2 (SiMe2),
−31.6 (SiMe2), −80.6 (SiMe), −118.3 ((Me3Si)2Si). UV absorption: λ = 265 nm (ε = 5.0 × 104 M−1·cm−1).
2,5-Bis(trimethylsilyl)-2,5-bis(dimethyl-2’-exo-norbornylsilyl)decamethylhexasilane (15). A solution of
tris(trimethylsilyl)silyl potassium (prepared from: tetrakis(trimethylsilyl)silane (2000 mg, 6.23 mmol)
and KOtBu (721 mg, 6.42 mmol) in DME (40 mL) at 60 ◦C) was added dropwise to a DME
(10 mL) solution of dimethyl-2-exo-norbornylchlorosilane (1294 mg, 6.85 mmol). After 24 h same
work up procedure as for
5 and crystallization out of acetone at rt. yielded colorless crystalline
2-(dimethyl-2’-exo-norbornylsilyl)-2-(trimethylsilyl)hexamethyltrisilane (15a) (1285 mg, 51%). Mp.:
◦
55–60 C. 1H-NMR (
0.16 (s, 3H, SiMe2). 13C-NMR (
(SiMe2)
0.5 (SiMe2). 29Si-NMR (
C18H44Si5 (400.97): C 53.92, H 11.06. Found: C 53.61, H 10.96.
δ
in ppm): 2.31 (s, 2H) 1.75–1.13 (m, 9H), 0.26 (s, 27H, 3 SiMe3), 0.21 (s, 3H, SiMe2),
in ppm): 38.8, 37.7, 37.1, 34.2, 33.5, 30.5, 28.8, 2.9 (3 SiMe3), 0.3
in ppm): 5.6 (SiMe2), 10.8 (SiMe3), 136.3 (Siq). Anal. calcd. for
δ
−
−
δ
−
−
−
A solution of 2-dimethyl-2’-exo-norbornylsilylhexamethyltrisilyl-2-potassium (prepared from 15a
(1285 mg, 3.20 mmol) and KOtBu (377 mg, 3.36 mmol) in THF (40 mL) at rt.) is slowly added to a
solution of 1,2-dichlorotetramethylsilane (300 mg, 1.6 mmol) in THF (10 mL). After 24 h same work up
◦
procedure as for
5
and crystallization out of acetone at
−
20 C yielded colorless crystalline 15 (1010 mg,
82%). Mp: 125–127 ◦C. 1H-NMR (δ in ppm): 2.50 (s, 4H) 1.62–0.90 (m, 18H), 0.57 (s, 12H, SiMe2), 0.34
and 0.33 (each s, 18H, SiMe3), 0.31 and 0.24 (each s, 6H, SiMe2). 13C-NMR (
in ppm): 39.9, 38.9, 37.1,
34.1, 33.8, 32.3, 28.8, 3.8 (SiMe3), 1.8 (2 SiMe3), 0.4 and 0.6 (SiMe2). 29Si-NMR (
in ppm): 5.2 (SiMe2),
127.4 (Siq). Anal. calcd. for C34H82Si10 (771.88): C 52.91, H 10.71.
Found: C 52.41, H 10.59. UV absorption: λ = 258 nm (ε = 7.1 × 104 M−1·cm−1).
δ
δ
−
−
9.7 (2 SiMe3),
−
29.1 (2 SiMe2),
−
2,5-Bis(trimethoxysilyl)-2,5-bis(trimethylsilyl)decamethylhexasilane (16). Tris(trimethyl-silyl)]-trimethoxy-
silylsilane (100 mg, 0.272 mmol) and KOtBu (32 mg, 0.285 mmol) were dissolved in THF (2 mL).