Bistable mesomorphism and supramolecular stereomutation
in chiral liquid crystal azopolymers
Jesús del Barrio
a
, Rosa M. Tejedor
a
, Luiz S. Chinelatto,
a
Carlos Sánchez,
b
Milagros Piñol
a
and Luis Oriol*
a
Synthesis of monomers
Compounds 1-6 were synthesized according to the methods previously described for 1S, 3S and
5S.
[50]
Characterization data are given below (main characterization data of the R-enantiomer of
the synthetic intermediates have been selected for simplicity).
(R)-4-Methylpropyloxynitrobenzene 1(R). Yellowish oil (92 % yield).
1
H NMR (400 MHz,
CDCl
3
, δ): 8.12 (d, J = 9.3 Hz, 2H), 6.88 (d, J = 9.3 Hz, 2H), 4.46-4.33 (m, 1H), 1.80-1.55 (m,
2H), 1.30 (d, J = 6.1 Hz, 3H), 0.94 (t, J = 7.5 Hz, 3H).
13
C-NMR (100 MHz, CDCl
3
, δ): 163.43,
140.77, 125.74, 115.04, 75.84, 28.81, 18.77, 9.42. IR (Nujol, cm
-1
): 2975, 2936, 2879, 1605,
1592, 1512, 1496, 1380, 1262, 1110, 846.
(R)-4-Methylheptyloxynitrobenzene 2(R). Yellowish oil (89 % yield).
1
H NMR (400 MHz,
CDCl
3
, δ): 8.13 (d, J = 9.3 Hz, 2H), 6.88 (d, J = 9.3 Hz, 2H), 4.50-4.40 (m, 1H), 1.79-1.66 (m,
1H), 1.63-1.51 (m, 1H), 1.49-1.16 (m, 11H), 0.84 (t, J = 6.9 Hz, 3H).
13
C-NMR (100 MHz,
CDCl
3
, δ): 163.44, 140.79, 125.78, 115.01, 74.75, 36.05, 31.60, 29.03, 25.20, 22.42, 19.28,
13.89. IR (Nujol, cm
-1
): 2929, 2855, 1605, 1592, 1512, 1495, 1379, 1261, 1109, 846.
(R)-4-Methylpropyloxyaniline 3(R). Yellow oil (91 % yield).
1
H NMR (400 MHz, CDCl
3
, δ):
6.74 (d, J = 8.7 Hz, 2H), 6.63 (d, J = 8.7 Hz, 2H), 4.15-4.07 (m, 1H), 3.55-3.18 (s broad, 2H),
1.75-1.50 (m, 2H), 1.24 (d, J = 6.1, 3H), 0.97 (t, J = 7.4, 3H).
13
C-NMR (100 MHz, CDCl
3
, δ):
151.20, 140.17, 117.90, 116.39, 76.41, 29.24, 19.41, 9.90. IR (Nujol, cm
-1
): 3428, 3357, 3220,
2969, 2920, 2876, 1603, 1541, 1508, 1462, 1232.
(R)-4-Methylheptyloxyaniline 4(R). Yellow oil (92 % yield).
1
H NMR (400 MHz, CDCl
3
, δ):
6.74 (d, J = 8.8 Hz, 2H), 6.64 (d, J = 8.8 Hz, 2H), 4.23-4.12 (m, 1H), 3.57-3.25 (s broad, 2H),
1.75-1.63 (m, 1H), 1.57-1.21 (m, 12H), 0.88 (t, J = 6.8, 3H).
13
C-NMR (100 MHz, CDCl
3
, δ):
151.25, 139.98, 117.87, 116.42, 72.20, 36.04, 31.60, 29.35, 25.60, 22.63, 19.88, 14.11. IR
(Nujol, cm
-1
): 3435, 3360, 3218, 2956, 2929, 2857, 1624, 1509, 1465, 1233, 823.
(R)-4-Methylpropyloxy-4'-hydroxyazobenzene 5(R). Yellow-orange crystalline leaflets (75 %
yield).
1
H NMR (400 MHz, CDCl
3
, δ): 7.89 (d, J = 9.0 Hz, 2H), 7.82 (d, J = 8.8 Hz, 2H), 7.01
(d, J = 9.0, 2H), 6.88 (d, J = 8.8, 2H), 4.47-4-36 (m, 1H), 1.86-1.60 (m, 2H), 1.34 (d, J = 6.1,
3H), 1.02 (t, J = 7.5, 3H).
13
C-NMR (100 MHz, CDCl
3
, δ): 160.38, 158.19, 146.88, 146.57,
124.50, 124.34, 115.91, 115.81, 75.37, 29.14, 19.16, 9.70. IR (KBr, cm
-1
): 3383 (broad), 2972,
2933, 1595, 1499, 1247, 1146, 842.
(R)-4-Methylheptyloxy-4'-hydroxyazobenzene 6(R). Yellow-orange crystalline leaflets (68 %
yield).
1
H NMR (400 MHz, CDCl
3
, δ): 7.85 (d, J = 9.0 Hz, 2H), 7.82 (d, J = 8.8 Hz, 2H), 6.97
(d, J = 9.0, 2H), 6.92 (d, J = 8.8, 2H), 4.49-4-40 (m, 1H), 1.84-1.71 (m, 1H), 1.66-1.54 (m, 1H),
1.51-1.21 (m, 11H), 0.88 (t, J = 6.8 Hz, 3H).
13
C-NMR (100 MHz, CDCl
3
, δ): 160.44, 157.71,
147.14, 146.57, 124.52, 124.40, 115.78, 115.75, 74.23, 36.39, 31.77, 29.24, 25.46, 22.58, 19.70,
14.07. IR (KBr, cm
-1
): 3388 (broad), 2955, 2928, 1597, 1501, 1247, 1146, 842.
Supplementary Material (ESI) for Journal of Materials Chemistry
This journal is (C) The Royal Society of Chemistry 2009