S. Debnath et al. / Dyes and Pigments 99 (2013) 447e455
449
1-9: 13.48 (s, 1H, eOH), 8.45 (s, 1H, eCH]Ne), 8.06 (dd, 2H,
J ¼ 2.0 Hz, J ¼ 7.6 Hz, ArH), 8.00 (dd, 3H, J ¼ 2.0 Hz, J ¼ 8.4 Hz, ArH),
7.83 (dd, 2H, J ¼ 2.0 Hz, J ¼ 6.8 Hz, ArH), 7.43 (dd, 2H, J ¼ 2.0 Hz,
J ¼ 7.2 Hz, ArH), 7.40 (t, 1H, J ¼ 8.0 Hz, ArH), 7.30 (d, 2H, J ¼ 8.8 Hz,
ArH), 6.52 (dd, 1H, J ¼ 2.4 Hz, J ¼ 7.6 Hz, ArH), 6.51 (d, 1H, J ¼ 2.0 Hz,
ArH), 4.01 (t, 2H, J ¼ 6.8 Hz, eOCH2e), 2.69 (s, 3H, AreCH3), 1.82e
1.27 (m, 14H, e(CH2)7e), 0.89 (t, 3H, J ¼ 6.4 eCH3). Elemental
Analysis calculated for C37H38N4O4: C, 73.73; H, 6.35% Found: C,
73.15; H, 6.31%.
2-9: 13.50 (s, 1H, eOH), 8.46 (s, 1H, eCH]Ne), 8.40 (dd, 2H,
J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.09 (dd, 1H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH),
8.06 (dd, 2H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.02 (d, 2H, J ¼ 8.0 Hz,
ArH), 7.45 (d, 2H, J ¼ 8.8 Hz, ArH), 7.41 (t, 1H, J ¼ 8.0 Hz, ArH), 7.31
(d, 2H, J ¼ 8.4 Hz, ArH), 6.52 (dd,1H, J ¼ 2.4 Hz, J ¼ 7.6 Hz, ArH), 6.51
(d, 1H, J ¼ 2.4 Hz, ArH), 4.02 (t, 2H, J ¼ 6.8 Hz, eOCH2e), 2.69 (s, 3H,
AreCH3), 1.82e1.27 (m, 14H, e(CH2)7e), 0.88 (t, 3H, J ¼ 6.4 eCH3).
Elemental Analysis calculated for C36H38N4O6: C, 69.44; H, 6.15%
Found: C, 69.14; H, 6.11%.
1-10: 13.48 (s, 1H, eOH), 8.45 (s, 1H, eCH]Ne), 8.06 (d, 2H,
J ¼ 8.8 Hz, ArH), 8.00 (d, 3H, J ¼ 8.0 Hz, ArH), 7.83 (d, 2H, J ¼ 8.8 Hz,
ArH), 7.43 (d, 2H, J ¼ 8.8 Hz, ArH), 7.39 (t, 1H, J ¼ 8.0 Hz, ArH), 7.30
(d, 2H, J ¼ 8.8 Hz, ArH), 6.53 (s, 1H, ArH), 6.51 (s, 1H, ArH), 4.01 (t,
2H, J ¼ 6.8 Hz, eOCH2e), 2.69 (s, 3H, AreCH3), 1.82e1.28 (m, 16H, e
(CH2)8e), 0.88 (t, 3H, J ¼ 6.4 eCH3). Elemental Analysis calculated
for C38H40N4O4: C, 74.00; H, 6.54% Found: C, 73.66; H, 6.45%.
1-11: 13.48 (s, 1H, eOH), 8.45 (s, 1H, eCH]Ne), 8.06 (d, 2H,
J ¼ 8.8 Hz, ArH), 8.00 (d, 3H, J ¼ 8.4 Hz, ArH), 7.82 (d, 2H, J ¼ 8.0 Hz,
ArH), 7.43 (d, 2H, J ¼ 8.8 Hz, ArH), 7.39 (t, 1H, J ¼ 8.0 Hz, ArH), 7.30
(d, 2H, J ¼ 9.2 Hz, ArH), 6.52 (s, 1H, ArH), 6.51 (s, 1H, ArH), 4.01 (t,
2H, J ¼ 6.4 Hz, eOCH2e), 2.69 (s, 3H, AreCH3), 1.83e1.27 (m, 18H, e
(CH2)9e), 0.88 (t, 3H, J ¼ 6.4 eCH3). Elemental Analysis calculated
for C39H42N4O4: C, 74.26; H, 6.71% found C, 74.01; H, 6.59%.
1-12: 13.48 (s, 1H, eOH), 8.45 (s, 1H, eCH]Ne), 8.06 (d, 2H,
J ¼ 8.8 Hz, ArH), 8.00 (d, 3H, J ¼ 8.0 Hz, ArH), 7.82 (d, 2H, J ¼ 8.4 Hz,
ArH), 7.43 (d, 2H, J ¼ 8.4 Hz, ArH), 7.39 (t, 1H, J ¼ 8.0 Hz, ArH), 7.30
(d, 2H, J ¼ 8.0 Hz, ArH), 6.52 (s, 1H, ArH), 6.51 (s, 1H, ArH), 4.01 (t,
2H, J ¼ 6.4 Hz, eOCH2e), 2.69 (s, 3H, AreCH3), 1.82e1.27 (m, 20H, e
(CH2)10e), 0.88 (t, 3H, J ¼ 6.4 eCH3). Elemental Analysis calculated
for C40H44N4O4: C, 74.51; H, 6.88% found C, 74.22; H, 6.66%.
2-4: 13.51 (s, 1H, eOH), 8.45 (s, 1H, eCH]Ne), 8.40 (dd, 2H,
J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.09 (dd, 1H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH),
8.06 (dd, 2H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.02 (d, 2H, J ¼ 8.0 Hz, ArH),
7.44 (d, 2H, J ¼ 8.8 Hz, ArH), 7.40 (t, 1H, J ¼ 8.0 Hz, ArH), 7.30 (d, 2H,
J ¼ 8.4 Hz, ArH), 6.51 (dd, 2H, J ¼ 2.4 Hz, J ¼ 7.6 Hz, ArH), 4.02 (t, 2H,
J ¼ 6.8 Hz, eOeCH2e), 2.69 (s, 3H, AreCH3), 1.83e1.32 (m, 4H, e
(CH2)2e), 0.90 (t, 3H, J ¼ 6.8 eCH3). Elemental Analysis calculated
for C31H28N4O6: C, 67.38; H, 5.34% Found: C, 67.00, H, 5.19%.
2-6: 13.50 (s, 1H, eOH), 8.46 (s, 1H, eCH]Ne), 8.40 (dd, 2H,
J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.09 (dd, 1H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH),
8.06 (dd, 2H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.02 (d, 2H, J ¼ 8.0 Hz,
ArH), 7.44 (d, 2H, J ¼ 8.8 Hz, ArH), 7.40 (t, 1H, J ¼ 8.0 Hz, ArH), 7.30
(d, 2H, J ¼ 8.4 Hz, ArH), 6.52 (dd, 1H, J ¼ 2.4 Hz, J ¼ 7.6 Hz, ArH), 6.51
(d, 1H, J ¼ 2.8 Hz, ArH), 4.01 (t, 2H, J ¼ 6.4 Hz, eOeCH2e), 2.69 (s,
3H, AreCH3), 1.83e1.32 (m, 8H, e(CH2)4e), 0.89 (t, 3H, J ¼ 6.8 e
CH3). Elemental Analysis calculated for C33H32N4O6: C, 68.26; H,
5.56% Found: C, 68.01; H, 5.42%.
2-10: 13.51 (s, 1H, eOH), 8.45 (s, 1H, eCH]Ne), 8.40 (dd, 2H,
J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.09 (dd, 1H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH),
8.06 (dd, 2H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.02 (d, 2H, J ¼ 8.0 Hz,
ArH), 7.45 (d, 2H, J ¼ 8.8 Hz, ArH), 7.41 (t, 1H, J ¼ 8.0 Hz, ArH), 7.30
(d, 2H, J ¼ 8.4 Hz, ArH), 6.52 (dd,1H, J ¼ 2.4 Hz, J ¼ 7.6 Hz, ArH), 6.51
(d, 1H, J ¼ 2.4 Hz, ArH), 4.02 (t, 2H, J ¼ 6.8 Hz, eOCH2e), 2.69 (s, 3H,
AreCH3), 1.82e1.27 (m, 16H, e(CH2)8e), 0.88 (t, 3H, J ¼ 6.4 eCH3).
Elemental Analysis calculated for C37H40N4O6: C, 69.79; H, 6.33%
Found: C, 69.65; H, 6.26%.
2-11: 13.50 (s, 1H, eOH), 8.46 (s, 1H, eCH]Ne), 8.40 (dd, 2H,
J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.09 (dd, 1H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH),
8.06 (dd, 2H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.02 (d, 2H, J ¼ 8.0 Hz,
ArH), 7.45 (d, 2H, J ¼ 8.8 Hz, ArH), 7.40 (t, 1H, J ¼ 8.0 Hz, ArH), 7.30
(d, 2H, J ¼ 8.4 Hz, ArH), 6.52 (dd,1H, J ¼ 2.4 Hz, J ¼ 7.6 Hz, ArH), 6.51
(d, 1H, J ¼ 2.4 Hz, ArH), 4.02 (t, 2H, J ¼ 6.8 Hz, eOCH2e), 2.69 (s, 3H,
AreCH3), 1.82e1.27 (m, 18H, e(CH2)9e), 0.88 (t, 3H, J ¼ 6.4 eCH3).
Elemental Analysis calculated for C38H42N4O6: C, 70.13; H, 6.51%
Found C, 70.11; H, 6.43%.
2-12: 13.50 (s, 1H, eOH), 8.45 (s, 1H, eCH]Ne), 8.40 (dd, 2H,
J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.09 (dd, 1H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH),
8.06 (dd, 2H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.02 (d, 2H, J ¼ 8.0 Hz,
ArH), 7.45 (d, 2H, J ¼ 8.8 Hz, ArH), 7.40 (t, 1H, J ¼ 8.0 Hz, ArH), 7.30
(d, 2H, J ¼ 8.4 Hz, ArH), 6.52 (dd,1H, J ¼ 2.4 Hz, J ¼ 7.6 Hz, ArH), 6.51
(d, 1H, J ¼ 2.4 Hz, ArH), 4.02 (t, 2H, J ¼ 6.4 Hz, eOCH2e), 2.69 (s, 3H,
AreCH3), 1.82e1.27 (m, 20H, e(CH2)10e), 0.88 (t, 3H, J ¼ 6.4 eCH3).
Elemental Analysis calculated for C39H44N4O6: C, 70.46; H, 6.67%
Found C, 70.36; H, 6.47%.
4. Results and discussion
Compounds 1-n and 2-n were synthesized following a very
simple and straight forward methodology of standard procedures
as described in Scheme 1. The empirical composition and the
molecular structures of all the final compounds were confirmed by
elemental analysis and spectral techniques respectively. The
analytical data is in good agreement with their chemical struc-
tures. All compounds in series 1-n and 2-n showed IR absorption
peaks of intensity between 2960 cmꢀ1 and 2850 cmꢀ1, indicating
the strong absorption band due to symmetrical and non-
symmetrical CeH stretching frequency. The other main observed
FTIR peaks confirmed the intramolecular H-bonding of OHeN at
2-7: 13.50 (s, 1H, eOH), 8.46 (s, 1H, eCH]Ne), 8.40 (dd, 2H,
J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.09 (dd, 1H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH),
8.06 (dd, 2H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.02 (d, 2H, J ¼ 8.0 Hz,
ArH), 7.44 (d, 2H, J ¼ 8.8 Hz, ArH), 7.40 (t, 1H, J ¼ 8.0 Hz, ArH), 7.30
(d, 2H, J ¼ 8.4 Hz, ArH), 6.52 (dd, 1H, J ¼ 2.4 Hz, J ¼ 7.6 Hz, ArH), 6.51
(d, 1H, J ¼ 2.8 Hz, ArH), 4.02 (t, 2H, J ¼ 6.8 Hz, eOeCH2e), 2.69 (s,
3H, AreCH3), 1.83e1.32 (m, 10H, e(CH2)5e), 0.90 (t, 3H, J ¼ 6.8 e
CH3). Elemental Analysis calculated for C34H34N4O6: C, 68.67; H,
5.76% Found: C, 68.44; H, 5.71%.
3190e3200 cmꢀ1
, C]O stretching band of ester at 1735e
1745 cmꢀ1, C]N stretching of an imine at 1608e1620 cmꢀ1, C]C
stretching of an aromatic ring 1490 cmꢀ1 and CeOeC stretching of
an ester w1290 and w1170 cmꢀ1. The cyano stretching band at
2221e2231 cmꢀ1 and NeO asymmetric stretch and NeO sym-
metric stretch of nitro group appeared at 1512e1521 and 1340e
1350 cmꢀ1 respectively.
2-8: 13.50 (s, 1H, eOH), 8.46 (s, 1H, eCH]Ne), 8.40 (dd, 2H,
J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.09 (dd, 1H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH),
8.06 (dd, 2H, J ¼ 2.0 Hz, J ¼ 8.8 Hz, ArH), 8.02 (d, 2H, J ¼ 8.0 Hz,
ArH), 7.45 (d, 2H, J ¼ 8.8 Hz, ArH), 7.41 (t, 1H, J ¼ 8.0 Hz, ArH), 7.31
(d, 2H, J ¼ 8.4 Hz, ArH), 6.52 (dd, 1H, J ¼ 2.4 Hz, J ¼ 7.6 Hz, ArH), 6.51
(d, 1H, J ¼ 2.4 Hz, ArH), 4.02 (t, 2H, J ¼ 6.8 Hz, eOCH2e), 2.69 (s, 3H,
AreCH3), 1.82e1.27 (m, 12H, e(CH2)6e), 0.88 (t, 3H, J ¼ 6.4 eCH3).
Elemental Analysis calculated for C35H36N4O6: C, 69.06; H, 5.96%
Found: C, 68.75; H, 5.89%.
The unsymmetrical four-ring molecules possess an alkoxy chain
attached at only one end of the bent core molecule, while the other
arm ends with a highly polar cyano or nitro substituents. The end
polar substituent in one of the arms contributes a large dipole
moment. The highly polarizable aromatic parts which have con-
jugated electrons contribute to the anisotropic dispersion potential
between them. The two neighbouring molecules with a strong
polar moiety at one end arrange to assemble in antiparallel