Mendeleev
Communications
Mendeleev Commun., 2014, 24, 140–142
Self-quenching and self-sensitization in the photochemistry
of a styrylquinoline–merocyanine dyad
Mikhail F. Budyka* and Vitalii M. Li
Institute of Problems of Chemical Physics, Russian Academy of Sciences, 142432 Chernogolovka,
Moscow Region, Russian Federation. Fax: +7 496 514 3244; e-mail: budyka@icp.ac.ru
DOI: 10.1016/j.mencom.2014.04.003
Forster resonance energy transfer from a styrylquinoline moiety to merocyanine results in the quenching of the former and the sensitiza-
tion of the latter in a novel styrylquinoline–merocyanine dyad and appears in the photoluminescence and photoisomerization of the dyad.
Dyads with photoactive chromophores (photochromes) can be
CHO
reversibly switched between different states upon light excitation
and used as the models of molecular devices, switches and logic
HO
gates.1–7 In a recently investigated bis-styrylquinoline dyad, both
N
MW
of the styrylquinoline chromophores underwent photoisomeriza-
tion so that the dyad could be photochemically switched from
one state to another.8 However, due to symmetry, both chromo-
phores of the dyad had the same absorption spectra that made
impossible the selective excitation of a particular chromophore; it
was also impossible to distinguish spectrally some dyad isomers.
To correct these drawbacks, we synthesized a novel non-sym-
metric styrylquinoline–merocyanine dyad SQ11MC [(E)-1-ethyl-
2-[2-(4-{11-[4-(2-quinolin-2-ylvinyl)phenoxy]undecyloxy}-
phenyl)vinyl]quinolinium perchlorate], where two chromophores
have different absorption spectra. The dyad SQ11MC was prepared
in four steps in an overall yield of 38%.† The synthetic route to
the SQ11MC dyad includes the condensation of quinaldine with
Me
N
OH
1
CHO
Br(CH2)11Br
HO
K2CO3, DMF
K2CO3,
MeCOEt
N
O
Br
11
2
N
Me
CHO
Et
I
N
N
LiClO4
O
11 O
†
(E)-2-[2-(4-Hydroxyphenyl)vinyl]quinoline 1 and (E)-2-{2-[4-(11-bromo-
3
undecyloxy)phenyl]vinyl}quinoline 2 were prepared using known pro-
cedures.9
For 1: yield 90%, mp 268°C (EtOH).
N
For 2: yield 75%, white crystals, mp 84–86°C (MeOH). 1H NMR
(CDCl3) d: 1.24–1.38 (m, 10H, CH2), 1.40–1.50 (m, 4H, CH2), 1.76–1.89
(m, 4H, CH2), 3.41 (t, 2H, BrCH2, J 6.8 Hz), 3.99 (t, 2H, OCH2, J 6.6 Hz),
6.91 (d, 2H, o-HC H , J 8.7 Hz), 7.26 (d, 1H, =CH, J 16.4 Hz), 7.48 (t,
ClO4
Et
O
O
11
4 (SQ11MC)
1H, quinoline, J 76.64Hz), 7.56 (d, 2H, m-HC H , J 8.7 Hz), 7.62 (d, 1H,
4
=CH, J 16.4 Hz), 7.64 (d, 1H, quinoline, J 8.66Hz), 7.68 (t, 1H, quinoline,
J 7.6 Hz), 7.76 (d, 1H, quinoline, J 8.4 Hz), 8.04 (d, 1H, quinoline, J 8.6 Hz),
8.09 (d, 1H, quinoline, J 8.7 Hz). IR (n/cm–1): 3057, 3037, 2937, 2851
Scheme 1
(E)-1-Ethyl-2-[2-(4-{11-[4-(2-quinolin-2-ylvinyl)phenoxy]undecyl-
oxy}phenyl)vinyl]quinolinium perchlorate SQ11MC 4. A mixture of 3
(0.23 mmol), N-ethylquinaldinium iodide (0.23 mmol) and 0.3 ml of
piperidine in 6 ml of methanol was refluxed for 6 h. After cooling, the
yellow precipitate was filtered off, washed twice with 5 ml of acetone
and dissolved in boiling ethanol. Then, 100 mg (0.94 mmol) of lithium
perchlorate was added and the perchlorate was filtered off after cooling,
washed twice with 5 ml of chloroform–hexane (1:1) to afford yellow crys-
talline powder of 4 (0.128 g, 72%); mp 241–243°C. 1H NMR (DMSO-d6)
d: 1.26–1.38 (m, 10H, CH2), 1.39–1.47 (m, 4H, CH2), 1.55 (t, 3H, Me,
J 7.2 Hz), 1.68–1.78 (m, 4H, CH2), 4.00 (t, 2H, OCH2, J 6.2 Hz), 4.08
(t, 2H, OCH2, J 6.3 Hz), 5.12 (q, 2H, CH2, J 7.2 Hz), 6.96 (d, 2H, C6H4,
J 8.8 Hz), 7.10 (d, 2H, C6H4, J 8.6 Hz), 7.29 (d, 1H, =CH, J 16.2 Hz), 7.51
(t, 1H, quinoline, J 7.6 Hz), 7.62–7.72 (m, 4H, quinoline, C6H4), 7.74 (d,
1H, =CH, J 16.2 Hz), 7.80 (d, 1H, quinoline, J 8.6 Hz), 7.88–7.98 (m, 5H,
quinoline, C6H4), 8.15 (t, 1H, quinoline, J 8.0 Hz), 8.25 (d, 1H, =CH,
J 15.6 Hz), 8.28–8.33 (m, 2H, quinoline), 8.52 (d, 1H, quinoline, J 8.8 Hz),
8.55 (d, 1H, quinoline, J 9.1 Hz), 8.98 (d, 1H, quinoline, J 9.0 Hz).
(nCH ), 1632 (nC=C), 1607, 1596, 1513, 1262 (nCOC), 1234, 1174, 974
2
(dCH=CH), 822, 749, 513 (dCBr). Found (%): C, 69.80; H, 7.24; N, 2.87.
Calc. for C28H34NOBr (%): C, 69.99; H, 7.13; N, 2.92.
(E)-4-{11-[4-(2-Quinolin-2-ylvinyl)phenoxy]undecyloxy}benzaldehyde 3.
A mixture of 2 (0.4 mmol), 4-hydroxybenzaldehyde (0.4 mmol) and
K2CO3 (1.2 mmol) in 5 ml of DMF was heated with stirring at 90–100°C
for 12 h. After cooling, the mixture was diluted with 20 ml of water, and
the precipitate was filtered off and recrystallized from methanol to afford
1
white crystals of product 3 (0.163 g, 78%); mp 116–118°C. H NMR
(CDCl3) d: 1.29–1.41 (m, 10H, CH2), 1.43–1.51 (m, 4H, CH2), 1.77–1.86
(m, 4H, CH2), 4.00 (t, 2H, OCH2, J 6.5 Hz), 4.04 (t, 2H, OCH2, J 6.5 Hz),
6.92 (d, 2H, C6H4, J 8.7 Hz), 6.98 (d, 2H, C6H4, J 8.7 Hz), 7.28 (d, 1H,
=CH, J 16.2 Hz), 7.47 (t, 1H, quinoline, J 7.6 Hz), 7.57 (d, 2H, C6H4,
J 8.7 Hz), 7.63 (d, 1H, =CH, J 16.2 Hz), 7.65 (d, 1H, quinoline, J 8.5 Hz),
7.69 (t, 1H, quinoline, J 7.7 Hz), 7.77 (d, 1H, quinoline, J 8.2 Hz), 7.82
(d, 2H, C6H4, J 8.7 Hz), 8.07 (d, 1H, quinoline, J 8.6 Hz), 8.10 (d, 1H,
quinoline, J 8.6 Hz), 9.87 (s, 1H, CHO). IR (n/cm–1): 3061, 3036, 2924,
2853 (nCH ), 1689 (nC=O), 1632 (nC=C), 1604, 1578, 1513, 1256 (nCOC),
IR (n/cm–1): 3037, 2937, 2854 (nCH ), 1591, 1573, 1513, 1256 (nCOC),
2
2
1233, 1164, 972 (dCH=CH), 829, 758. Found (%): C, 80.75; H, 7.46; N, 2.53.
Calc. for C35H39NO3 (%): C, 80.58; H, 7.54; N, 2.68.
1234, 1167, 1087, 967 (dCH=CH), 833, 764. Found (%): C, 72.53; H, 6.79;
N, 3.53. Calc. for C47H51N2O6Cl (%): C, 72.80; H, 6.63; N, 3.61.
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