Scheme 1 The crosslinking of poly(propyl methacrylate siloxane) and NISS (l~365 nm), and the release of the tetralone oxime protecting group
(l~254 nm). Note the sequential use of ultraviolet radiation of two different frequencies.
recorded as a function of duration of ultraviolet irradiation
(l~254 nm).
(16.0 g, 0.099 mol) was dissolved in pyridine (37 cm3), yielding
a deep brown solution. Crude styrene-p-sulfonyl chloride
(22.14 g, 0.11 mol) was added dropwise with stirring and
cooling in an ice±water bath. The mixture was stirred at 15 ³C
for 3 h, and then poured into an ice-cold solution of
concentrated hydrochloric acid (60 cm3) in water (360 cm3).
The resulting red mixture was extracted into chloroform
(36150 cm3), yielding a red organic solution which was washed
with water (50 cm3) and then dried over anhydrous potassium
carbonate overnight. After ®ltration to remove the desiccant,
the chloroform was removed under vacuum, leaving a thick red
oil.
Syntheses
1-Tetralone oxime. Tetralone (98%, Aldrich) and hydroxyl-
amine hydrochloride (99%, Aldrich) were used without further
puri®cation. 1-Tetralone (3,4-dihydronaphthalen-1(2H)-one)
(20.6 g, 0.14 mol) and hydroxylamine hydrochloride (15.7 g,
0.23 mol) were dissolved in a mixture of ethanol (55 cm3, AR
grade) and water (14 cm3). Sodium hydroxide (28 g, 0.70 mol,
powder) was slowly added as the mixture was stirred in an ice±
water bath. The mixture was re¯uxed for 5 min, cooled to room
temperature and then poured, with vigorous stirring, into a
solution of concentrated hydrochloric acid (83 cm3) in water
(550 cm3). The creamy solid that formed was recovered by
®ltration, washed with water and dried in a vacuum oven at
50 ³C for 3 h. 1-Tetralone oxime was recovered as an off-white
solid (20.6 g, 0.13 mol, 93% of theoretical yield): mp~104±
The product oil was continuously extracted with boiling
heptane (5620 cm3). On cooling, a ¯uffy white precipitate
formed. After recovery by ®ltration the white solid was
recrystallised from toluene by slow addition of methanol.
The 1,2,3,4-tetrahydro-1-naphthylideneamino styrene-p-sulfo-
nate (NISS) (3.69 g, 0.011 mol, 11.3% of theoretical yield)
[literature value:20 23% yield (the discrepancy arises from the
rigorous puri®cation of the product in this study)] was
recovered as a brilliant, white ¯uffy powder; mp~81±83 ³C
1
2
106 ³C. H NMR: d 7.9 (1H, d, J~9); 7.3±7.2 (3H, m); 2.9
2
(2H, t, J~6); 2.8 (2H, t, 2J~6); 1.9 (2H, m). 13C NMR: d
155.5 (CLN±OH) [literature value18
d 155]; 139.9(ar.),
1
[literature value:20 80±82 ³C]. H NMR: d 7.15±8.01 (8H, m);
130.5(ar.), 129.2(ar.), 128.7(ar.), 126.5(ar.), 124.1(ar.),
29.8(al.), 23.9(al.), 21.3(al.).
6.75 (1H, dd); 5.45±5.90 (2H, dd); 2.83 (2H, t); 2.73 (2H, t); 1.84
(2H, m) [literature values:20 d 7.14±8.0 (8H, m); 6.77 (1H, dd);
5.45±5.9 (2H, dd); 2.84 (2H, t, 2J~6); 2.73 (2H, t, 2J~6); 1.85
(2H, m)]. 13C NMR: d 162.4 (CLN±O±S); 143.0 (ar.), 141.1
(ar.), 135.3 (ar.), 134.6 (ar.), 131.1 (ar.), 128.3 (ar.), 128.8 (ar.),
128.0 (ar.), 126.5 (ar.), 125.3 (ar.), 118.0 (ar.), 29.3 (al.), 25.4
(al.), 21.0 (al.). Infrared (see Table 3): 1369 and 1177 cm21
(SLO str.) [literature values:20 1370, 1180 cm21]. Ultraviolet:
Styrene-p-sulfonyl chloride. Sodium styrene-p-sulfonate
(Aldrich), quinol (99%, BDH) and phosphorus pentachloride
(95%, Aldrich) were used without further puri®cation. Synth-
esis of styrene-p-sulfonyl chloride was as reported by Iwakura
et al.19 Quinol (0.41 g, 0.037 mol) was added to a suspension of
sodium styrene-p-sulfonate (36.4 g, 0.18 mol) in chloroform
(180 cm3). Phosphorus pentachloride (47 g, 0.23 mol) was then
added slowly to the suspension (cooled in an ice±water bath).
After heating the mixture for 2 h at 45±50 ³C, the precipitate
was removed by ®ltration and the chloroform removed under
vacuum. The resulting yellow liquid was dissolved in diethyl
ether (150 cm3) and then, after cooling to 0 ³C, washed
carefully with ice-cold water (2650 cm3). The ethereal solution
was dried over anhydrous calcium chloride and stored in a
freezer overnight to minimise any polymerisation. After the
ether was removed under vacuum, crude styrene-p-sulfonyl
chloride was obtained as a yellow liquid (22.14 g, 0.11 mol,
63% of theoretical yield) and used immediately; no further
puri®cation was carried out as this leads to polymerisation of
the product.19
l
max~256 nm, e~24 000 dm3 mol21 cm21 in chloroform.
Poly(propyl methacrylate siloxane) (PMS). 3-(Trimethoxy-
silyl)propyl methacrylate (97%, Aldrich) was used without
further puri®cation. 3-(Trimethoxysilyl)propyl methacrylate
(10.01 g, 4.0361022 mol) was stirred with a mixture of ethanol
(9.28 g, 0.20 mol), water (2.19 g, 0.12 mol) and hydrochloric
acid (32.2 cm3, 0.10 mol dm23, 3.261023 mol) at 50 ³C for
2.5 h. Low boiling temperature materials were removed under
vacuum. The resulting thick colourless oil was dissolved in
toluene and ®ltered to remove any insoluble material. The
toluene was then removed under vacuum. Poly(propyl
methacrylate siloxane) was recovered as a thick clear, colour-
less oil (6.85 g, 3.8061022 mol, 94% yield). Infrared (see
Table 3): 3000±2890 (C±H str. sat., m); 1719 (CLO str., a,b-
unsat. ester, m); 1637 (CLC str. a,b-unsat. ester, s); 1453 (CH2
deformation); 1322; 1298 (C±O str. ester); 1167±1013 (Si±O±Si,
1,2,3,4-Tetrahydro-1-naphthylideneamino styrene-p-sulfonate
(NISS). Pyridine (AnalaR grade, BDH) was stored over
activated molecular sieve (grade 5A). 1-Tetralone oxime
s); 940 cm21 1H NMR: d 6.04 and 5.49 (1H each, broad,
.
850
J. Mater. Chem., 2000, 10, 849±858