Article
Chem. Mater., Vol. 22, No. 7, 2010 2249
(270 MHz, CDCl3): δ 7.88 (d, 2 H, J=8.2 Hz), 7.26 (d, 2 H, J=
8.2 Hz), 3.37 (t, 2 H, J=6.4 Hz), 2.83 (t, 2 H, J=7.4 Hz), 2.57 (s, 3
H), 2.22 - 2.11 (m, 2 H). 13C NMR (67.5 MHz, CDCl3): 197.66,
128.84, 128.74, 146.36, 135.51, 34.03, 33.74, 32.74, and 26.62
ppm. Elem. anal. Calcd for C11H13BrO: C, 54.79; H, 5.43.
Found: C, 54.88; H, 5.24.
Synthesis of 1-(4-(3-Bromopropyl)phenyl)ethanol (4). 3 (4.624
g, 19 mmol) was diluted with methanol (60 mL) in a reaction
flask under an inert atmosphere. The reaction flask was cooled
in an ice bath. NaBH4 (0.75 g, 20 mmol) was added to the
mixture over 5 min. The mixture was stirred for an additional
2 h. Saturated NaCl (70 mL) was added to the mixture and the
product was extracted with CH2Cl2 (2 ꢀ 20 mL). The organic
phase was washed with saturated NaCl (3 ꢀ 50 mL). The solvent
was removed under a vacuum to recover the crude product,
which was purified by flash chromatography using 50% hexane/
50% ethyl acetate (Rf = 0.68 by TLC) and then by semi-
preparative HPLC using 60% hexane/40% ethyl acetate to give
4 as a colorless liquid (yield 60%). 1H NMR (270 MHz, CDCl3):
δ 7.29 (d, 2 H, J=8.2 Hz), 7.17 (d, 2 H, J=8.2 Hz), 4.87-4.85 (m,
1 H), 3.38 (t, 2 H, J=6.6 Hz), 2.76 (t, 2 H, J=7.4 Hz), 2.20-2.10
(m, 2 H), 1.86-1.85 (m, 1 H), 1.49-1.46 (m, 3 H). 13C NMR
(270 MHz, CDCl3): 143.79, 139.87, 128.76, 125.69, 70.26, 34.22,
33.69, 33.13, and 25.18 ppm. Elem. anal. Calcd for C11H15BrO:
C, 54.34; H, 6.22. Found: C, 54.59; H, 6.28.
Figure 1. Schematic representation of controlled film formation and
sequential layer depositions from 1.
Synthesis of 1-(3-Bromopropyl)-4-vinylbenzene (5). 4 (3.169 g,
13 mmol) and p-toluenesulfonic acid (0.125 g, 0.7 mmol) were
dissolved in toluene (200 mL). The reaction mixture was re-
fluxed for 3 h in an inert atmosphere, and water was removed
with a Dean-Stark collector. The mixture was washed with
water (3 ꢀ 50 mL), the solvent was removed under a vacuum,
and crude product was purified by flash chromatography using
90% hexane/10% ethyl acetate (Rf =0.75 by TLC) and then
semipreparative HPLC using 99% hexane and 1% ethyl acet-
1
ate to give 5 as a colorless liquid (yield 47%). H NMR (270
MHz, CDCl3): δ 7.36 (d, 2 H, J=8.2 Hz), 7.17 (d, 2 H, J=8.2
Hz), 6.71 (q, 1 H), 5.76-5.70 (m, 1 H), 5.24 - 5.20 (m, 1 H),
3.40 (t, 2 H, J=6.7 Hz), 2.78 (t, 2 H, J=7.2 Hz), 2.19-2.14 (m, 2
H). 13C NMR (270 MHz, CDCl3): 140.33, 136.66, 135.74,
128.84, 126.47, 113.37, 34.17, 33.78, and 33.14 ppm. Elem.
anal. Calcd for C11H13Br: C, 58.69; H, 5.82. Found: C, 58.63;
H, 5.99.
Figure 2. Plausible film structure highlighting the triple function of 1.
a Waters 600 pump and Waters 2487 detector equipped
with a semiprep flow cell. The detection wavelength was
255 nm. The column was a Nova-Pak Silica, 6 μm, 19 ꢀ
300 mm. The flow rate was 10 mL/min. Elemental analyses
were performed by Desert Analytics (Tucson, Arizona).
Gas chromatography with electron impact ionization and
mass spectrometry was performed with a Hewlett-Packard
G1800A GCD System using a ValcoBond VB-5 capillary
column (30 m ꢀ 0.25 mm ꢀ 25 μm) and a temperature gradient
from 80 to 300 ꢀC.
Synthesis of 3-(4-Vinylphenyl)propane-1-thiol (1). Thiourea
(2.5 g, 33 mmol) was added to the solution of 5 (2.0 g, 9 mmol) in
methanol (100 mL), and the mixture was refluxed for 16 h in an
inert atmosphere. The solution was cooled to room temperature
and NaOH (10 mL, 12%) was added. The solution was refluxed
for 4 h to hydrolyze the thiouronium salt. 1N H2SO4 was added
dropwise until neutral pH. Fifty milliliters of water was added
and the product was extracted with CH2Cl2 (3 ꢀ 50 mL). The
organic phase was washed with water (2 ꢀ 50 mL) and then
saturated NaCl (2 ꢀ 50 mL). The solvent was removed under a
vacuum, and the product was purified by flash chromatography
on silica gel using CH2Cl2 (Rf = 0.95 by TLC) and then
semipreparative HPLC using 98% hexane and 2% ethyl acetate.
The solvent was removed under vacuum to give 1 as a colorless
liquid (74%). 1H NMR (270 MHz, CDCl3): δ 7.33 (d, 2 H, J=
7.9 Hz), 7.13 (d, 2 H, J=7.9 Hz), 6.69 (q, 1 H), 5.75 - 5.66 (m,
1 H), 5.23-5.16 (m, 1 H), 2.71 (t, 2 H, J=7.2 Hz), 2.52 (q, 2 H),
1.35 (t, 1 H, J=7.9 Hz). 13C NMR (67.5 MHz, CDCl3): 141.07,
136.67, 135.54, 128.71, 126.36, 113.18, 35.43, 34.13, 24.01 ppm.
EIMS (178 (70) [Mþ], 144 (56) [C11H12þ], 117 (100) [C9H9þ].
Elem. anal. Calcd for C11H14S: C, 74.10; H, 7.91. Found: C,
74.38; H, 7.62.
Synthesis of 1-(4-(3-Bromopropyl)phenyl)ethanone (3). AlCl3
(15.0 g, 110 mmol) was added to CH2Cl2 (100 mL) under an inert
atmosphere. The reaction flask was cooled in an ice bath. Acetic
anhydride (5.6 g, 55 mmol) diluted with CH2Cl2 (5 mL) was then
added over 30 min. The mixture was stirred for an additional
15 min. 2 (5.0 g, 25 mmol) was diluted with CH2Cl2 (5 mL) and
was added to the reaction mixture over 30 min. The mixture was
stirred for an additional 2 h while being cooled in an ice bath.
The mixture was slowly poured onto 200 g of crushed ice. The
organic phase was washed with 10% HCl (3 ꢀ 50 mL), saturated
NaHCO3 (3 ꢀ 50 mL), and saturated NaCl (3 ꢀ 50 mL). The
solvent was removed under a vacuum, and crude product was
purified by flash chromatography using CH2Cl2 (Rf=0.99 by
TLC) and then by semipreparative HPLC using 75% hexane/
1
25% ethyl acetate to give 3 as a liquid (yield 55%). H NMR