from hexane. Yield 80%, mp 45 ¡C. 1H NMR d (CDCl ):
Conclusions
3
0.70È0.80 (m, 4H, CH ), 0.96 (t, J \ 6.98 Hz, 6H, CH ), 1.32È
2
3
The results reported herein o†er simple methods for the prep-
aration of compounds belonging to the class of bis-
(pyrrolyl)arylenes. Bis(pyrrolyl)dioxanethiophene was obtained
in moderate yield by using two di†erent routes. The modiÐed
Lucchesini procedure can be easily adapted for the short syn-
thesis of 2,5-bis(pyrrol-2-yl)-1,4-dioxane[2,3-c]thiophene start-
ing from commercially available 2,3-dihydrothieno[3,4-b][1,4]
dioxin.
The structures and properties of synthesized molecules were
also modeled theoretically with the aim of determining the
relation of their properties to their polymerization potentials.
The correlation between experimentally determined oxidation
potentials and theoretically established structures (the dihe-
dral angle r) and ionization potentials indicates the important
role of the ÈOR substituent. The oxygen atom present in the
substituent interacts with the pyrrole ring, stabilizing the
planar structure. Planar molecules possess lower ionization
potentials compared to values found for nonplanar moieties.
The calculated ionization potentials correlate well with the
oxidation potentials. The newly synthesized molecules
(nonplanar 18a and planar 18b) Ðt well with these trends. The
charge distribution change due to the ionization correlates
well with the expected sites of polymerization.
1.36 (m, 36 H, CH ), 1.92È2.06 (m, 4H, CH ), 7.4È7.54 (m, 6H,
2
2
arom. H). 13C NMR d (CDCl ): 14.1, 22.6, 22.7, 23.7, 29.2,
29.6, 30.0, 31.9, 40.3, 54.8, 119.6, 122.9, 126.9, 130.5 141.3,
3
150.6. Anal. calc. for C
67.05; H, 8.40%.
H
Br : C, 67.26; H, 8.54; found C,
37 56
2
9,9-Didodecyl-2,7-dicyanoÑuorene (13).
A
mixture of
copper(I) cyanide (0.4 g, 4.5 mmol) and compound 12 (1.0 g,
1.5 mmol) in DMF (30 mL) was reÑuxed for 24 h. The mixture
was poured into a solution of ammonia (20 mL, 15%) to form
a precipitate. The solid was collected by Ðltration and washed
with an ammonia solution, followed by water. The solid was
recrystallized from acetone to give yellow crystals. Yield 70%,
mp 156È157 ¡C. 1H NMR d (CDCl ): 0.73È0.81 (m, 4H, CH ),
3
2
0.97 (t, J \ 7.0 Hz, 6H, CH ), 1.13È1.26 (m, 36H, CH ), 1.92È
3
2
2.0 (m, 4H, CH ), 7.60 (d, J \ 8.3 Hz, 4H, arom. H), 7.82 (s,
2
2H, arom. H). 13C NMR d (CDCl ): 14.1, 22.6, 22.8, 29.2, 29.5,
3
29,6, 30.0, 31.91, 40.4, 54.8, 119.6, 122.8, 126.1, 126.8, 130.5,
142.2, 151.4. Anal. calc. for C
5.06; found C, 84.55; H, 10.0; N, 4.90%.
H
N : C, 84.72; H, 10.21; N,
39 56
2
9,9-DidodecylÑuorene-2,7-dicarboxylic acid (14a). A mixture
of compound 13 (1.0 g. 1.8 mmol) and phosphoric acid (17.2
mL) in water (2.55 mL) was stirred under nitrogen at 170 ¡C
for 24 h. The mixture was poured into hot water to precipitate
the diacid 14a, which was isolated by Ðltration and washed
repeatedly with water. The crude product was recrystallized
from methanol to give white crystals. Yield 75%, mp 305 ¡C.
Experimental
General
Melting points are uncorrected. All NMR spectra were
acquired using a Brucker VXR-300 at 300 (1H) and 75 (13C)
MHz in CDCl using TMS as internal standard. Column
1H NMR d (DMSO): 0.8 (s, 4H, CH ), 0.97 (t, J \ 6.87 Hz,
2
6H, CH ), 1.13È1.62 (m, 36 H, CH ), 1.92È2.07 (m, 4H, CH ),
3
2
2
3
2.52 (s, 2H, OH), 7.78È7.82 (m, 6H, arom. H). 13C NMR d
(CDCl ): 14.1, 22.6, 22.8, 29.2, 29.5, 29.6, 30.1, 31.8, 40.5, 54.8,
122.8, 126.2, 126.8, 130.4, 141.5, 151.4, 167.4. Anal. calc. for
chromatography was carried out on Merck Kiesel silica gel
60. Dry THF was used immediately after distilling from a
solution containing benzophenoneÈsodium. Other starting
materials, reagents and solvents were used as received from
suppliers.
3
C
H
O ; C, 79.27; H, 9.89; found C, 79.0; H, 9.6%.
39 58
4
9,9-DidodecylÑuorene-2,7-dicarboxylic acid dichloride (15a).
A mixture of compound 14a (1.0 g, 1.8 mmol), thionyl chloride
(15 mL) and 2 drops of anhydrous DMF was stirred at room
temperature for 12 h and then stirred at 50 ¡C for 1 h. Excess
thionyl chloride was removed under reduced pressure. The
crude product was taken up in chloroform and treated with
activated charcoal, Ðltered and crystallized to give yellowish-
green crystals. Yield 81%, mp 134È135 ¡C. 1H NMR d
(CDCl ): 0.72 (s, 4H, CH ), 0.96 (t, J \ 6.54 Hz, 6H, CH ),
Syntheses
9,9-DidodecylÑuorene (11). BunLi (1.6 M solution in hexane,
1.8 mmol) was added to a solution of Ñuorene (1.00 g, 6 mmol)
in THF (50 mL) at [60 ¡C over a period of 5 min. The
resulting solution was stirred at [60 ¡C for 1.5 h. A solution
of 1-bromododecane (2.99 g, 1.2 mmol) in THF (10 mL) was
added dropwise and stirring continued at [60 ¡C for 30 min.
Ammonium chloride (5 g in 30 mL of water) was added, then
the organic layer was separated and dried over anhydrous
magnesium sulfate. The solvent was removed under reduced
pressure and the crude oily product was puriÐed by column
chromatography, eluent: (1) hexane, (2) hexaneÈethyl acetate
3
2
3
0.94È1.3 (m, 36 H, CH ), 1.92È2.06 (m, 4H, CH ), 7.4 (d,
2
2
J \ 7.6 Hz, 2H, arom. H), 7.8 (s, 2H, arom. H), 8.0 (d, J \ 7.5
Hz, 2H, arom. H). 13C NMR d (CDCl ): 14.1, 22.5, 22.8, 29.1,
29.5, 29.6, 30.2, 31.7, 40.5, 54.7, 119.6, 126.8, 130.4, 133.3, 141.4,
3
152.6, 168.0. Anal. calc. for C
found C, 74.2; H, 8.62%.
H
Cl O : C, 74.61; H, 8.99;
39 56
2 2
(2 : 1). Yield 80%. 1H NMR d (CDCl ): 0.71È0.82 (m, 4H,
3
CH ), 0.97 (t, J \ 6.99 Hz, 6H, CH ), 1.92È2.06 (m, 4H, CH ),
2
3
2
1.32È1.62 (m, 36H, CH ), 7.37È7.48 (m, 6H arom. H), 7.78È7.80
9,9-DidodecylÑuorene-2,7-dicarboxylic acid diallylamide
(16a). A solution of compound 15a (1.0 g, 1.6 mmol) in dry
benzene (30 mL) was added slowly with vigorous stirring to a
solution of allylamine (0.2 g, 3.5 mmol) and triethylamine (0.35
g, 3.5 mmol) in dry benzene (10 mL). The mixture was stirred
at room temperature for 6 h and then heated for 1 h at 50 ¡C.
The mixture was cooled and the precipitate was collected by
Ðltration and washed with benzene. Recrystallization from
methanol a†orded colorless needles. Yield 80%, mp 169È
170 ¡C. 1H NMR d (CDCl ): 0.70 (s, 4H, CH ), 0.95 (t, J \ 6.6
2
(m, 2H, arom. H). 13C NMR d (CDCl ): 14.1, 22.6, 22.7, 23.7,
29.2, 29.6, 30.0, 31.9, 40.3, 54.9, 119.6, 122.8, 126.9, 130.6, 141.1,
150.6. Anal. calc. for C
83.2; H, 11.35%.
3
H
: C, 83.37; H, 11.62; found C,
37 58
9,9-Didodecyl-2,7-dibromoÑuorene (12). Bromine (0.15 mL,
3.0 mmol) in CH Cl was added quickly to a stirred solution
2
2
of compound 11 (2.01 g, 4.0 mmol) and I (1.0 mg, 0.4 mmol)
2
in CH Cl (20 mL) at room temperature. The reaction
2
2
3
2
mixture was stirred at room temperature for 20 h. An aqueous
Hz, 6H, CH ), 0.94È2.1 (m, 36 H, CH ), 1.92È2.1 (m, 4H, CH ),
3
2
2
solution of NaHSO (15 mL, 15%) was added and the
resulting two phases were stirred until the color disappeared
(30 min). The organic layer was separated, washed with water
and dried over MgSO . The volatiles were removed under
4.13 (t, J \ 7.2 Hz, 4H, NHCH ), 5.09 (d, J \ 14 Hz, 2H,
3
2
2CH ), 5.30 (d, J \ 9.1 Hz, 2H, 2CH ), 6.95È6.99 (m, 2H,
2,
2
CHCH ), 7.31È7.45 (m, 4H, arom. H), 7.8 (br s, 2H, arom. H).
2
13C NMR d (CDCl ): 14.1, 22.5, 22.8, 29.0, 29.5, 29.6, 30.1,
31.7, 40.5, 115.3, 119.5, 122.5, 126.9, 130.6, 135.5, 143.6, 151.7,
4
3
reduced pressure and the crude product was recrystallized
New J. Chem., 2001, 25, 1175È1181
1179