=
Synthesis of [NC–C6H4–C(H) N(H)–B12H11][N(n-Bu)4],
[2][N(n-Bu)4]
The suspension was stirred at r.t. overnight. The title compound
was extracted from the methanol solution using diethyl ether.
After evaporation of the solvent, the crude product was washed
with 100 mL of water. Further recrystallization in diethyl ether
The monoamino derivative [B12H11NH3]− (1) was prepared from
[B12H12]2− as described by Hertler and Raash.2 The synthesis of
=
yielded 0.123 g (0.5 mmol, 50%) of pure H3CN CHC6H4–
−
=
[NC–C6H4–C(H) N(H)–B12H11] (2) was conducted from 1 by
=
CH CH–C6H4–CN (6) (Found: C, 83.2; H, 6.3; N, 10.5%. 6
following the procedure reported by Sivaev et al.29 The DSC
analysis of 2 shows a melting point at 241 ◦C followed by a
strong exothermic effect starting at 248 ◦C.
requires C, 82.9; H, 5.7; N, 11.4%); dH (CD3CN, 300 MHz) 3.41
3
=
(s, 3H, N–CH3), 7.10 (d, 1H, HC CH, JH–H = 16.4),7.20 (d,
3
=
1H, HC CH, JH–H = 16.4), 7.74 (s, 4H, C6H4), 7.83 (d, 2H,
=
C6H4), 7.96 (d, 2H, C6H4), 8.19 (s, 1H, N CH–); dC (CD3CN,
=
=
Synthesis of [NC–C6H4–CH CH–C6H4–C(H) N(H)–B12H11]-
75 MHz) 48.46 (1C, N–CH3), 127.36 (4C, C6H4), 128.14 (1C,
[N(n-Bu)4], [3][N(n-Bu)4]
=
=
HC CH), 128.65 (2C, C6H4), 131.92 (1C, HC CH), 132.92
(2C, C6H4), 136.48 (1C, C6H4), 138.75 (1C, C6H4), 141.95 (1C,
In a first step, diethyl p-cyanobenzylphosphonate was synthe-
sized according to a procedure previously reported by Kagan
et al.35 In a second step, 4-cyano-4ꢀ-formylstilbene was prepared
by the procedure described below, consistent with a patent
deposited by Reinehr.49 1.87g (33 mmol) of potassium hydroxide
was dissolved in 25 mL of methanol at 45 ◦C. The solution
was cooled to 0 ◦C, and then 4.09g (31 mmol) of tereph-
thalaldehyde were added. Then 6.9g (25 mmol) of diethyl p-
cyanobenzylphosphonate were added dropwise during 2 hours.
The mixture was heated at 40 ◦C during 2 hours, and then
allowed to cool to r.t. 10 mL of methanol were added and the
solution was kept under stirring during 12 hours. A pale yellow
precipitate was obtained and subsequently isolated by filtration.
The ensuing solid was washed with 250 mL of methanol,
yielding 4.89g (21.2 mmol, 85%) of 4-cyano-4ꢀ-formylstilbene
(7). (Found: C, 82.8; N, 5.9; O, 6.5; H, 4.6%. 7 requires C,
C6H4), 151.12 (1C, C6H4), 161,83 (1C, HC N); tmax/cm−1 2215
=
◦
=
(CN), 1640 (C N) (KBr); DSC analysis: mp 146 C.
=
=
Synthesis of [NC–C6H4–CH CH–C6H4–CH CH–C6H4–
C(H) N(H)–B12H11][N(n-Bu)4], [4][N(n-Bu)4]
=
In a first step, p-xylylene-bis(triphenylphosphonium chloride)
(8) was synthesized from triphenylphosphine and p-xylylene
dichloride, as described in the literature.37 In a second step,
2.124 g (3.0 mmol) of p-xylylene-bis(triphenylphosphonium
chloride) and 0.219 g (1.6 mmol) of 4-cyanobenzaldehyde were
dissolved into 30 mL of freshly distilled ethanol. A solution of
0.187 g (3.5 mmol) of NaOCH3 into 50 mL of ethanol was added
dropwise. After 12 hours of stirring at r.t., 0.432 g (3.2 mmol) of
terephthalaldehyde was added to the reaction mixture, and then
a solution of 0.221 g (4.1 mmol) of NaOCH3 in 50 mL of ethanol
was added dropwise. The color of the solution turned to pale
yellow and the mixture was kept under stirring at r.t. during 12 h.
The reaction mixture was concentrated under vacuum, yielding
a yellow precipitate which was filtered off. The precipitate was
washed with a mixture water/ethanol (1 : 1). Further recrystal-
lization in DMF yielded 0.201 g (0.6 mmol, 20%) of (E,E)-4-(2-
(4-(2-(4-cyanophenyl)ethenyl)phenyl)ethenyl)benzaldehyde (9).
82.4; N, 6.0; O, 6.9; H 4.7%); dH (CD3CN, 300 MHz) 7.43 (s,
2H, HC CH), 7.74 (s, 4H, C6H4), 7.83 (d, 2H, C6H4, JH–H
3
=
=
3
8.29), 7.96 (d, 2H, C6H4, JH–H = 8.29), 10.01 (s, 1H, CHO);
dC (CD3CN, 75 MHz) 111.79 (1C, C6H4), 119.16 (1C, C6H4),
=
127.73 (4C, C6H4), 129.84 (1C, HC CH), 130.47 (2C, C6H4),
=
131.22 (1C, HC CH), 132.65 (2C, C6H4), 136.48 (1C, C6H4),
142.06 (1C, C6H4), 191 (1C, C O); tmax/cm−1 2215 (CN), 1687
=
(CHO) (KBr). DSC analysis: mp 210 ◦C; strong exothermic
=
dH (CD3CN, 300 MHz) 7.18 (m, 4H, HC CH), 7.50–7.60 (m,
effect starting at 382 ◦C.
8H, C6H4), 7.63 (d, 2H, C6H4), 7.81 (d, 2H, C6H4), 10 (s, 1H,
-CHO).
In a third step, 0.442g (1.0 mmol) of [B12H11NH3][NBu4]
and 0.183g (0.8 mmol) of 7 were dissolved in 30 mL of
dichloromethane. A few drops of an aqueous solution of sodium
hydroxide (5 wt%) were then added to the mixture. The reaction
mixture was stirred overnight at r.t. The solvent was removed
in vacuum and further purification was performed by chro-
matography on silicagel (NORMASIC 40 lm-60 lm, Aldrich)
using a CH3CN/CH2Cl2 (4 : 1) solution and yielded, after
evaporation of the solvent in vacuum, 0.31g (0.5 mmol, 60%)
In a third step, 0.107 g (0.32 mmol) of 9 and 0.262 g
(6.54 mmol) of 1 were dissolved in 20 mL of DMF. The
pH of the solution was adjusted to 9–10 by adding a few
drops of aqueous sodium hydroxide (5 wt%). The color of
the solution turned to orange. The mixture was kept un-
der stirring at r.t. during 24 hours. Then DMF was evacu-
ated under vacuum. Further purification was performed by
chromatography on silicagel (NORMASIC 40 lm-60 lm,
Aldrich) using CH2Cl2 then a CH3CN/CH2Cl2 (1 : 4) solution
and yielded, after evaporation of the solvent in vacuum,
=
=
of pure [NC–C6H4–CH CH–C6H4–C(H) N(H)–B12H11][N(n-
Bu)4], [3][N(n-Bu)4]. dH (CD3CN, 300 MHz) 0.2–2.0 (unresolved,
B–H), 0.87 (t, 12H, N–(CH2)3CH3), 1.28 (m, 8H, N–(CH2)2–
=
18 mg (0.025 mmol, 8%) of pure [NC–C6H4–CH CH–C6H4–
CH2–CH3), 1.51 (m, 8H, N–CH2–CH2–CH2–CH3), 3.02 (t, 8H,
=
=
CH CH–C6H4–C(H) N(H)–B12H11][N(n-Bu)4], [4][N(n-Bu)4].
dH (DMSO, 500 MHz) 0.2–2.0 (u, B–H), 0.98 (t, 12H, N–
(CH2)33), 1.38 (m, 8H, N–(CH2)2–CH2–CH3), 1.65 (m, 8H, N–
3
=
N–CH2–(CH2)2–CH3), 7.42 (d, 1H, HC CH, JH–H = 16.39 Hz),
=
7.49 (d, 1H, HC CH), 7.77 (s, 4H, NC–C6H4), 7.79 (d, 2H,
3
C6H4, JH–H = 8.47 Hz), 7.96 (d, 2H, C6H4), 8.75 (d, 1H,
CH2–CH2–CH2–CH3), 3.12 (t, 8H, N–CH2–(CH2)2–CH3), 7.32
3
=
=
HC NH, JH–H = 19.78 Hz), 10.43 (d, 1H, HC NH); dC
(CD3CN, 75 MHz) 12.23 (4C, N–(CH2)3CH3), 18.76 (4C, N–
(CH2)2–CH2–CH3), 23.73 (4C, N–CH2–CH2–CH2–CH3), 58.79
(4C, N–CH2–(CH2)2–CH3), 111.59 (1C, C6H4), 119.16 (1C, CN),
3
=
=
(d, 2H, HC CH, JH–H = 16.2 Hz), 7.59 (d, 2H, HC CH),
3
7.65 (s, 4H, C6H4), 7.83 (d, 4H, C6H4, JH–H = 8.28 Hz),
3
=
7.94 (d, 4H, C6H4) 8.71 (d, 2H, HC NH, JH–H = 19.59 Hz),
=
10.34(d, 2H, HC NH); dC (DMSO, 125 MHz) 13.59 (4C,
=
128.03 (4C, C6H4), 129.12 (1C, C6H4), 130.80 (1C, HC CH),
131.53 (2C, C6H4 together with 1C, HC CH), 131.64 (2C, C6H4
together with 1C, HC CH), 133.18 (2C, C6H4), 141.59 (1C,
N–(CH2)3CH3), 20.09 (4C, N–(CH2)2–CH2–CH3), 24.06 (4C,
N–CH2–CH2–CH2–CH3), 59.02 (4C, N–CH2–(CH2)2–CH3),
110.50 (1C, C6H4), 119.16 (1C, CN), 123.01 (2C, C6H4), 126.92
=
=
=
C6H4), 143.99 (1C, C6H4)169.31 (1C, HC NH); dB{H} (CD3CN)
=
(2C, C6H4), 128.48 (4C, HC CH), 129.18 (4C, C6H4), 132.50
(2C, C6H4), 134.75 (2C, C6H4), 134.88 (1C, C6H4), 140.01
(2C, C6H4), 144.42 (1C, C6H4), 145.41 (1C, C6H4), 154.19 (1C,
−3.58 (s, 1B), −14.64 (u, 11B); tmax/cm−1 3286, 3248 (NH), 2487
−
−
=
(B–H), 2223 (CN), 1640 (C N) (KBr); m/z (FAB ) 372 (M );
DSC analysis: Tg = 89 ◦C, strong exothermic effect starting at
260 ◦C.
=
HC NH).
=
=
Synthesis of NC–C6H4–CH CH–C6H4–C(H) N–CH3 (6)
Acknowledgements
In a typical experiment, 0.220 g (1.0 mmol) of 7 were added to
6 mL of an aqueous solution of monomethylamine (40 wt%).
The authors are grateful to B. Fenet (NMR analysis center,
UCBL) for his significant assistance in obtaining the NMR data.
3 0 7 0
D a l t o n T r a n s . , 2 0 0 5 , 3 0 6 5 – 3 0 7 1