Liquidꢀcrystalline crownꢀcontaining copolymers
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 12, December, 2007 2419
umn chromatography (toluene—ethyl acetate, 1 : 1, as the eluꢀ
ent). The yield was 0.34 g (60%). IR, ν/cm–1: 2936, 2856 (CH2);
1720 (C=O); 1632 (CH2=CH—); 1600, 1512 (C=C, Ar); 1256
(C—O—C, ArOR); 1168 (C—O—C). 1H NMR (CDCl3),
δ: 1.26—1.87 (m, 8 H, 4 CH2); 3.38—3.75 (m, 21 H, CH, 10
CH2O); 4.05—4.52 (m, 8 H, 4 CH2O); 5.77 and 6.35 (both d,
1 H each, CH2=CH—, J = 10.7 Hz, J = 17.3 Hz); 6.14 (dd, 1 H,
CH2=CH—, J = 10.4 Hz, J = 17.8 Hz); 6.91 (d, 2 H, Ar, J =
9.3 Hz); 7.9 (d, 2 H, Ar, J = 8.9 Hz).
In the last step, monomer Mꢀ3 was synthesized. For this
purpose, ABA (0.09 g, 0.0003 mol), compound 7 (0.2 g,
0.4 mmol), and 4ꢀdimethylaminopyridine (0.01 g) were disꢀ
solved in anhydrous THF (15 mL). Then DCC (0.09 g,
0.42 mmol) was added to the solution cooled with ice water for
1.5 h. The reaction mixture was kept at ~20 °C for 24 h. The
progress of the reaction was monitored by TLC. The precipitate
of dicyclohexylurea that formed in the course of the reaction
was filtered off, and THF was evaporated. The product was
purified by column chromatography (toluene—ethyl acetate,
1,4,7,10,13,16ꢀHexaoxacyclooctadecanꢀ2ꢀylmethyl 4ꢀ[(E)ꢀ
4ꢀ(2ꢀacryloyloxyethyl)(ethyl)aminophenyldiazenyl]benzoate
(Mꢀ2). Azo compound 1 was synthesized by the azoꢀcoupling
reaction with amine in an acidic medium analogously to the
procedure described earlier.21 In the second step, triethylamine
(2 mL) was added to a solution of azo compound 1 (3.1 g,
0.01 mol) in anhydrous THF (100 mL). Then acryloyl chloride
(1.35 g, 0.015 mol) was added dropwise to the reaction solution
cooled with ice water for 1 h. The progress of the reaction was
monitored by TLC. Within 12 h after the beginning of the reacꢀ
tion, the precipitate of triethylamine hydrochloride that formed
was filtered off, and THF was evaporated. The compound was
purified by column chromatography (chloroform—methanol,
10 : 1, as the eluent). The yield of compound 2 was 2 g (55%).
Compound Mꢀ2 was synthesized by mixing compound 2 (0.37 g,
1 mol), 2ꢀ(hydroxymethyl)ꢀ18ꢀcrownꢀ6 (Merck) (0.35 g,
1.2 mmol), and 4ꢀdimethylaminopyridine (0.02 g) in anhydrous
THF (20 mL). Then DCC (0.29 g, 1.4 mmol) was added to the
reaction solution cooled with ice water for 1.5 h. The reaction
mixture was kept at ~20 °C for 24 h. The progress of the reaction
was monitored by TLC. After completion of the reaction, the
precipitate of dicyclohexylurea that formed was filtered off,
and THF was evaporated. The product was purified by column
chromatography (chloroform—methanol, 7 : 1, as the eluent).
The yield was 0.29 g (45%). IR, ν/cm–1: 2934, 2853 (CH2);
1714, 1691 (C=O); 1627 (CH2=CH—); 1595, 1506 (C=C, Ar);
1378 (C—N); 1130 (C—O—C). 1H NMR (CDCl3), δ: 1.15 (t,
3 H, Me, J = 7.2 Hz); 3.32—3.75 (m, 25 H, CH, 12 CH2O);
4.21—4.60 (m, 6 H, 3 CH2); 5.78 and 6.37 (both d, 1 H each,
CH2=CH—, J = 10.5 Hz, J = 16.6 Hz); 6.12 (dd, 1 H,
CH2=CH—, J = 10.7 Hz, J = 17.5 Hz); 6.93 (d, 2 H, Ar,
J = 9.3); 7.75 (d, 4 H, Ar, J = 9.1 Hz); 8.18 (d, 2 H, Ar, J = 8.9 Hz).
4ꢀ[4ꢀ(1,4,7,10,13,16ꢀHexaoxacyclooctadecanꢀ2ꢀylmethoxyꢀ
carbonyl)phenyldiazenylphenyl 4ꢀ(6ꢀacryloyloxyhexyloxy)]ꢀ
benzoate (Mꢀ3). In the first step, azo dye 3 was synthesized by
the azoꢀcoupling reaction of pꢀaminobenzoic acid with phenol
in an alkaline medium.21 In the second step, the hydroxy group
of azo dye 3 was protected with chloroethoxyformate according
to a standard procedure.22 The third step involved the formation
of acid chloride 5 by the reaction of compound 4 with thionyl
chloride.22 In the fourth step, triethylamine (2 mL) was added
to a solution of 2ꢀhydroxymethylꢀ18ꢀcrownꢀ6 (0.29 g, 1 mmol)
in anhydrous THF (30 mL). Then acid chloride 5 (0.4 g,
1.2 mmol) was added dropwise to the reaction solution cooled
with ice water for 1 h. The progress of the reaction was moniꢀ
tored by TLC. Within 12 h after the beginning of the reaction,
the precipitate of triethylamine hydrochloride that formed was
filtered off, and THF was evaporated. The compound was puriꢀ
fied by column chromatography (chloroform as the eluent). The
yield of compound 6 was 0.4 g (70%).
1 : 1, as the eluent). The yield was 0.11 g (65%). IR, ν/cm–1
:
2926, 2861 (CH2); 1700 (C=O); 1610 (CH2=CH—); 1587, 1490
(C=C, Ar); 1263 (C—O—C, ArOR); 1118 (C—O—C). 1H NMR
(CDCl3), δ: 1.26—1.87 (m, 8 H, 4 CH2); 3.4—3.75 (m, 21 H,
CH, 10 CH2O); 4.00—4.52 (m, 8 H, 4 CH2O); 5.78 and 6.37
(both d, 1 H each, CH2=CH—, J = 11.0 Hz, J = 17.8 Hz); 6.15
(dd, 1 H, CH2=CH—, J = 10.0 Hz, J = 17.4 Hz); 7.01 (d, 2 H,
Ar, J = 9.6 Hz); 7.48 (d, 2 H, Ar, J = 9.2 Hz); 7.72 (d, 2 H, Ar,
J = 8.9 Hz); 8.15 (d, 6 H, Ar, J = 9.0 Hz).
Methyl
4ꢀ[4ꢀ(2ꢀacryloyloxyethyl)(ethyl)aminophenylꢀ
diazenyl]benzoate (Mꢀ4). Compound 2 (0.5 g, 1.4 mmol), anhyꢀ
drous methanol (0.1 mL, 2 mmol), and 4ꢀdimethylaminopyriꢀ
dine (0.03 g) were mixed in anhydrous THF (20 mL). Then
DCC (0.4 g, 2 mmol) was added to the solution cooled with ice
water for 1.5 h. The reaction mixture was kept at ~20 °C for
24 h. The progress of the reaction was monitored by column
chromatography. Then the precipitate of dicyclohexylurea that
formed was filtered off and THF was evaporated. The product
was purified by column chromatography (chloroform—methaꢀ
nol, 10 : 1, as the eluent). The yield was 0.29 g (55%). IR,
ν/cm–1
: 2931, 2849 (CH2); 1718, 1697 (C=O); 1630
(CH2=CH—); 1598, 1510 (C=C, Ar); 1381 (C—N); 1142
(C—O—C). 1H NMR (CDCl3), δ: 1.15 (t, 3 H, Me, J = 7.2 Hz);
3.35 (m, 4 H, 2 CH2); 3.87 (c, 3 H, OMe); 4.26 (t, 2 H, CH2,
J = 5.9 Hz); 5.78 and 6.37 (both d, 1 H each, CH2=CH—, J =
10.5 Hz, J = 16.6 Hz); 6.12 (dd, 1 H, CH2=CH—, J = 11.1 Hz,
J = 17.5 Hz); 6.93 (d, 2 H, Ar, J = 9.3 Hz); 7.75 (d, 4 H,
Ar, J = 9.5); 8.18 (d, 2 H, Ar, J = 9.0 Hz).
Synthesis of polymers (general procedure). All copolymers
were prepared by the radical copolymerization of monomers
Mꢀ1, Mꢀ2, Mꢀ3, or Mꢀ4 with Mꢀ5 initiated by azoisobutyric
acid dinitrile (2 wt.%). To purify the copolymers from lowꢀ
molecularꢀweight compounds and oligomeric products, the samꢀ
ples were refluxed in methanol for 6 h. The compositions of the
copolymers were determined by UV spectroscopy. Since the
copolymerization was carried out to high degrees of conversion,
the difference between the compositions of the final copolymers
and the starting monomeric mixtures was at most 4%.
Complexes of copolymers with potassium perchlorate (general
procedure). The copolymers were dissolved in anhydrous THF.
Then a solution of potassium perchlorate in anhydrous acetoniꢀ
trile was added to the solution of the copolymer. The resulting
solution was concentrated with slight heating. The complexes
thus prepared were kept in vacuo at 80 °C to remove the residual
solvent.
It is known that the stability constant of the complex of
18ꢀcrownꢀ6 ether with potassium perchlorate varies in the range
of 106—108 L mol–1 depending on the polarity of the solvent.
Hence, the equilibrium in the reversible reaction (Scheme 5) is
almost completely shifted to the right. The high stability conꢀ
stant is associated with the good match between the atomic
In the fifth step, the hydroxy group was deprotected with
ammonia to prepare phenol 6.22