New photosensitive polymers: Synthesis and free radical polymerization of oxypyridinium and oxyisoquinolinium functionalized methacrylate and styrene derivatives

Article abstract of DOI:10.1021/ma011750b

Polymerizable hydroxypyridinium and hydroxyisoquinolinium salts 1a-4a, 2d, and 3d have been prepared from vinylbenzyl chloride or glycidyl methacrylate and 3-hydroxypyridine (2), 4- or 5-hydroxyisoquinoline (1, 3), and 8-hydroxyquinoline (4). Radical homo- and copolymerization with styrene or methyl methacrylate of the salts 1a-3a, 2d, and 3d produced (co)polymers 1e, 2e, 2f, 3f, 1g, 2g, 2h, and 3h. The photosensitive dipolar oxypyridinium or oxyisochinolinium betaine structures were generated in solutions with triethylamine from the low molecular weight and polymeric salt precursors. For the model compounds 1b-4b and (co)polymers 1e, 2e, 2f, 3f, 1g, 2g, 2h, and 3h, the degradation of the longest wavelength absorption of this betaine structure was detected during UV irradiation. UV irradiation of the model compound N-benzyl-4-hydroxyisochinolinium chloride (1b) in the presence of triethylamine produced the expected aziridine type structure 1k by intramolecular cyclization.

Full text of DOI:10.1021/ma011750b

4
258
Macromolecules 2002, 35, 4258-4265
New Photosensitive Polymers: Synthesis and Free Radical
Polymerization of Oxypyridinium and Oxyisoquinolinium Functionalized
Methacrylate and Styrene Derivatives
Ver en a G o1 r tz a n d Helm u t Ritter *
J ohannes Gutenberg-Universit a¨ t Mainz, Institut f u¨ r Organische Chemie,
Duesbergweg 10-14, 55128 Mainz, Germany
Received October 9, 2001; Revised Manuscript Received February 20, 2002
ABSTRACT: Polymerizable hydroxypyridinium and hydroxyisoquinolinium salts 1a -4a , 2d , and 3d have
been prepared from vinylbenzyl chloride or glycidyl methacrylate and 3-hydroxypyridine (2), 4- or
5
-hydroxyisoquinoline (1, 3), and 8-hydroxyquinoline (4). Radical homo- and copolymerization with styrene
or methyl methacrylate of the salts 1a -3a , 2d , and 3d produced (co)polymers 1e, 2e, 2f, 3f, 1g, 2g, 2h ,
and 3h . The photosensitive dipolar oxypyridinium or oxyisochinolinium betaine structures were generated
in solutions with triethylamine from the low molecular weight and polymeric salt precursors. For the
model compounds 1b-4b and (co)polymers 1e, 2e, 2f, 3f, 1g, 2g, 2h , and 3h , the degradation of the
longest wavelength absorption of this betaine structure was detected during UV irradiation. UV irradiation
of the model compound N-benzyl-4-hydroxyisochinolinium chloride (1b) in the presence of triethylamine
produced the expected aziridine type structure 1k by intramolecular cyclization.
In tr od u ction
Sch em e 1
We have reported the synthesis and photochemical
behavior of polymers with dipolar mesoionic and nitron
1
-6
functions as side groups or within the main chain.
UV irradiation of these highly polar dipoles leads to
much less polar products via an intramolecular disro-
7
tatoric cyclization reaction. This ring closure changes
the physical properties of polymeric materials including
solubility, absorption of UV light, film thickness, and
refractive index.
We now extended our studies on photosensitive
polymers with pyridiniumolates and (iso)quinoliniumo-
lates as photoisomerizable dipolar groups.
were used as received. 4-Hydroxyisoqouinoline was synthe-
sized according to the literature.2 Technical solvents, styrene
2,23
8
(Acros Organics, 99%), and MMA (Fluka, 99%) were distilled
before use. Solvents of p.a. quality were purchased from Riedel
de Haen. The TLC analysis was carried out using silica gel
plates (60 F 254) purchased from Merck. The spots were
visualized by UV fluorescence quenching and by development
with iodine. For flash-chromatography silica gel with 30 to 60
µm particle size purchased from Baker was used. Melting
points were determined with an instrument from B u¨ chi and
Katritzky’s studies focused on the thermally induced
dipolar cycloaddition reactions of various pyridiniumo-
lates with olefins,9-14 1,3-dienes,
11-14
and ketenes and
15
also on dimerization reactions.1
2,13,16
Upon irradiation,
1
13
1
7
are uncorrected. H NMR (200 MHz) and C NMR (50.3 MHz)
spectra were recorded (at room temperature) on a Bruker AC
this type of betaine forms dimers or bicyclic aziridines
via intermolecular or intramolecular ring closure. The
isoquinolinium series also undergo thermal dipolar
2
00 using the signal of the deuterated solvent as lock and
internal standard for chemical shift data in the δ-scale relative
to TMS. For infrared spectroscopy a Nicolet FT-IR 5DXC
1
8-20
cycloadditions.
Moreover, Hansen and Undheim
2
1
reported the reversible valence isomerism between the
N-aryl-4-oxyisoquinolinium betaine A and the N-aryl
bicyclic aziridine B upon irradiation as shown in Scheme
(DTGS detector) or a 5SXB (MCT detector) was used. UV-vis
spectra were performed on a Zeiss-MCS320/MCS340 diode
array spectrometer. Field desorption (FD) mass spectrometry
was done using a Finnigan MAT 95. Elementary analysis was
carried out in the analytical laboratory of the institute of
organic chemistry at the University of Mainz. Molecular
modeling calculations were implemented using PC Spartan Pro
1
.
This paper reports for the first time the synthesis and
co)polymerization of styrene and methacryloyl substi-
(
tuted 3-hydroxypyridinium, 4- and 5-hydroxyisoquino-
linium, and 8-hydroxyquinolinium salts. Furthermore,
the photochemistry of the free betaine structure, gener-
ated by alkaline treatment of the salt precursors, is
discussed.
1
.07; the density functional theory (DFT) method pBP/DN*
was used for geometry optimizations and energy calculations.
Syn th esis of Hyd r oxyp yr id in iu m a n d Hyd r oxy(iso)-
qu in olin iu m Ch lor id es. N-Ben zyl-3-h yd r oxyp yr id in iu m
Ch lor id e (2b). A solution of benzyl chloride (12.0 g, 124 mmol)
and 3-hydroxypyridine (8.0 g, 62 mmol) in dry acetone (100
mL) was stirred for 48 h at room temperature. The white
precipitate was collected, and from the filtrate, the solvent was
evaporated. More crude product separated after the addition
of acetonitrile. The product was recrystallized from acetoni-
trile. Yield: 16.2 g (76%), colorless crystals. Mp: 154-156 °C
Exp er im en ta l Section
Ma t er ia ls a n d Met h od s. The materials benzyl chloride
(
Fluka, 99%), vinylbenzyl chloride (Fluka, 95%, mixture of
isomers (70% para and 30% meta)), 3-hydroxypyridine (Fluka,
8%), 5-hydroxyisoquinoline (Aldrich, 90%), 8-hydroxyquino-
9
2
5
(
lit.: 158-159 °C).
line (Fluka, 99%), glycidyl methacrylate (Fluka, 97%), potas-
sium peroxodisulfate (Fluka, 99%), AIBN (Fluka, 98%), and
ion-exchange resin Amberlite IRA-410 (Fluka, 20-40 mesh)
1
H NMR (DMSO-d ): δ [ppm] ) 12.50 (br s, 1H, OH), 8.83
(s, 1H, H-2), 8.72 (d, 1H, J 5,6 ) 5.9 Hz, H-6), 8.11 (dd, 1H, J 2,4
6
1
0.1021/ma011750b CCC: $22.00 © 2002 American Chemical Society
Published on Web 04/27/2002

Macromolecules, Vol. 35, No. 11, 2002
New Photosensitive Polymers 4259
+
)
)
2.2 Hz, J 4,5 ) 8.5 Hz, H-4), 7.95 (dd, 1H, J 5,6 ) 5.9 Hz, J 4,5
MS (FD): m/z (%) ) 237 (18) [MH - Cl], 236 (27) [M+
-
+
+
8.5 Hz, H-5), 7.56-7.03 (m, 5H, ar-H), 5.78 (s, 2H, CH
2
).
): δ [ppm] ) 157.51 (C-3), 134.32 (C-
), 135.32, 132.62, 131.71, 129.15 (C-2, C-4, C-5, C-6), 129.02
Cl], 235 (100) [M - HCl], 145 (60) [5-hydroxyisoquinolinium ].
N-Vin ylben zyl-5-h ydr oxyisoqu in olin iu m Ch lor ide (3a).
A solution of 5-hydroxyisoquinoline (1.0 g, 7 mmol), vinylbenzyl
chloride (1.1 g, 7 mmol) and a small amount of hydroquinone
in dry ethanol (30 mL) was stirred for 72 h. After evaporation
of the solvent, the residue was purified by flash chromatog-
1
3
C NMR (DMSO-d
6
CH
2
(
ar-CH-para), 128.65, 128.60 (ar-CH-ortho, ar-CH-meta), 62.97
CH ).
N-Vin ylben zyl-3-h yd r oxyp yr id in iu m Ch lor id e (2a ). Vi-
nylbenzyl chloride (15.2 g, 0.1 mol) was added to a solution of
-hydroxypyridine (9.5 g, 0.1 mol) and a small amount of
(
2
raphy (methanol). Yield: 1.5 g (71%), red solid. Mp: 81 °C.
1
3
6
H NMR (DMSO-d ): δ [ppm] ) 9.57 (d, 1H, J 1,3 ) 2.4 Hz,
hydroquinone in dry acetone (70 mL). After the reaction was
stirred for 48 h at room temperature under exclusion of light
and moisture, the solvent was removed by evaporation. The
product crystallized on addition of acetonitrile and a grain of
N-benzyl-3-hydroxypyridinium chloride (2b) to the remaining
oil. Yield: 17.4 g (70%), colorless, hygroscopic crystals. Mp:
H-1), 8.33 (d, 1H, J 3,4 ) 6.8 Hz, H-3), 8.08 (t, 1H, J 7,6+8 ) 9.3
Hz, H-7), 7.64-7.37 (m, 5H, ar-H, H-4), 6.76 (d, 1H, J 6,7 ) 9.3
Hz, H-6), 6.71 (dd, 1H, J cis ) 11.2 Hz, J trans ) 18.0 Hz, CHd
CH ), 6.56 (d, 1H, J 7,8 ) 8.3 Hz, H-8), 5.85 (dd, 1H, J gem ) 2.9
2
+
Hz, J trans ) 18.0 Hz, CHdCHHtrans), 5.71 (s, 2H, N -CH
(dd, 1H, J gem ) 2.9 Hz, J cis ) 11.2 Hz, CHdCHHcis).
2
), 5.29
1
3
1
12 °C.
6
C NMR (DMSO-d ): δ [ppm] ) 162.81 (C-5), 148.5, 148.36,
1H NMR (DMSO-d
): δ [ppm] ) 12.50 (br s, 1H, OH), 8.84
134.12, 133.41, 122.67, 118.90, 111.32, 111.24 (C-1, C-3, C-4,
C-6, C-7, C-8), 137.91, 137.83 (ar-C-CHdCH ), 135.91, 135.80
(CHdCH ), 135.06 (ar-C-CH ), 130.64, 130.12 (C-9, C-10),
129.47, 129.32, 128.92, 127.95, 126.68 (ar-CH), 115.61, 115.32
6
(
1
d, 1H, J 5,6 ) 5.9 Hz, H-6), 8.70-8.73 (m, 1H, H-2), 8.11 (d,
H, J 4,5 ) 8.5 Hz, H-4), 7.93 (dd, 1H, J 5,6 ) 5.9 Hz, J 4,5 ) 8.5
Hz, H-5), 7.70-7.39 (m, 4H, ar-H), 6.72 (dd, 1H, J cis ) 10.7
Hz, J trans ) 17.7 Hz, CHdCH ), 5.87 (dd, 1H, J gem ) 3.2 Hz,
trans ) 17.7 Hz, CHdCHHtrans), 5.77 (s, 2H, N -CH
dd, 1H, J gem ) 3.2 Hz, J cis ) 10.7 Hz, CHdCHHcis).
2
2
2
+
2
(CHdCH
2
2
), 62.45, 62.25 (N -CH ).
+
-1
J
(
2
), 5.30
IR (KBr): [cm ] ) 3390 (O-H), 3083, 3032, 3005 (ar C-H),
2500 (br, pyr O-H), 1628, 1573, 1503 (CdC, CdN), 991, 915
1
3
C NMR (DMSO-d
ar-C-CHdCH ), 135.86, 135.76 (CHdCH
31.67, 129.38 (C-2, C-4, C-5, C-6), 134.75, 133.78, 129.09,
28.64, 128.12, 126.97, 126.71, 126.50 (ar-CH), 115.52, 115.44
6
): δ [ppm] ) 157.48 (C-3), 137.95, 137.88
2
(CHdCH out of plane), 848, 829, 793, 777 (ar C-H out of
(
1
1
2
2
), 135.33, 132.66,
plane) and 1469, 1452, 1413, 1382, 1318, 1286, 1090, 760, 740,
713.
+
+
MS (FD): m/z (%) ) 523 (89) [M
2
- 2HCl], 263 (41) [MH
+
+
+
(
CHdCH
2
), 62.84, 62.67 (N -CH
2
).
- Cl], 262 (100) [M - Cl], 261 (18) [M - HCl], 144.8 (35)
-
1
+
IR (KBr): [cm ] ) 3371 (br, O-H), 3056, 3029 (ar C-H),
[5-hydroxyisoquinolinium ].
2
1
7
979, 2829 (aliph C-H), 2727,2614, 2510 (pyr O-H), 1628,
N-(2-Hyd r oxy-1-m eth a cr yloyloxyp r op yl-3)-5-h yd r oxy-
isoqu in olin iu m Ch lor id e (3d ). N-(2-Hydroxy-1-methacryl-
oyloxypropyl-3)-5-oxyisoquinolinium betaine (3c, 1.60 g, 5.6
mmol) was stirred in water (10 mL). When half concentrated
aqueous acid chloride was slowly added until a pH of 1 was
reached, the remaining solid dissolved and the red solution
eventually turned to orange. After the addition of 200 mL of
chloroform and vigorous shaking, the solid precipitated and
concentrated at the interface. It was filtered off and washed
with chloroform. Yield: 1.60 g (89%), light yellow solid. Mp:
2
584, 1510 (CdC, CdN), 994, 919 (CHdCH out of plane), 807,
64 (ar C-H out of plane), and 1447, 1266, 1148, 1032.
+
+
MS (FD): m/z (%) ) 212 (3) [M - Cl], 211 (100) [M
-
HCl].
Anal. Calcd for C14
.65; (O), 6.46; Cl, 14.31. Found: C, 67.53; H, 6.02; N, 5.58;
O), 6.75; Cl, 14.12.
N-(2-Hyd r oxy-1-m eth a cr yloyloxyp r op yl-3)-3-h yd r oxy-
H
14NOCl (247.72): C, 67.88; H, 5.70; N,
5
(
p yr id in iu m Ch lor id e (2d ). N-(2-Hydroxy-1-methacryloyloxy-
propyl-3)-3-oxypyridinium betaine (2c, 2.90 g, 12 mmol) was
dissolved in water (10 mL) and stirred. Half concentrated
aqueous acid chloride was slowly added until a pH of 1 was
reached. After distillation under reduced pressure the residue
was purified by flash chromatography (chloroform/ methanol,
184-186 °C.
1
H NMR (DMSO-d ): δ [ppm] ) 11.73 (s, 1H, hetar-OH),
6
9.95 (s, 1H, H-1), 8.66 (d, 1H, J 3,4 ) 6.8 Hz, H-3), 8.55 (d, 1H,
J
J
7,8 ) 9.8 Hz, H-8), 7.95-7.83 (m, 2H, H-7, H-6), 7.63 (d, 1H,
3,4 ) 6.8 Hz, H-4), 6.11 (s, 1H, CdCHHcis), 5.88 (br s, 1H,
1
:1). Yield: 2.41 g (69%), colorless solid. Mp: 134-137 °C.
CH-OH), 5.72 (s, 1H, CdCHHtrans), 4.95 (d, 1H, J gem ) 12.7
1
+
H NMR (DMSO-d
6
): δ [ppm] ) 8.55 (s, 1H, H-2), 8.47-
Hz, N -CHH
a
), 4.62 (dd, 1H, J vic ) 8.5 Hz, J gem ) 12.7 Hz,
+
8
.45 (m, 1H, H-6), 8.05-8.01 (m, 1H, H-4), 7.90-7.87 (m, 1H,
N -CHH
b
), 4.25 (m, 3H, CH-OH, CH
C NMR (DMSO-d ): δ [ppm] ) 166.27 (CdO), 153.15 (C-
5), 150.23, 134.23, 132.18, 120.36, 120.04, 118.30 (C-1, C-3,
C-4, C-6, C-7, C-8), 135.47 (CdCH ), 128.04, 128.00 (C-9, C-10),
126.33 (CdCH ), 67.60 (CH-OH), 65.62 (CH
CH ), 17.95 (CH ).
2
-O), 1.90 (s, 3H, CH
3
).
1
3
H-5), 6.11 (s, 1H, CdCHHcis), 5.70 (s, 1H, CdCHHtrans), 4.76
6
+
+
(
4
d, 1H, J gem ) 12.2 Hz, N -CHH
a
), 4.48 (br. s, 1H, N -CHH
-O), 1.88 (s, 3H, CH ).
): δ [ppm] ) 166.26 (CdO), 157.37 (C-
), 135.66, 133.60, 131.45, 127.76 (C-2, C-4, C-5, C-6), 135.46
), 126.34 (CdCH ), 67.68 (CH-OH), 65.49 (CH -O),
), 17.95 (CH ).
b
),
.15 (br. s, 3H, CH-OH, CH
2
3
2
1
3
+
C NMR (DMSO-d
6
2
2
-O), 63.07 (N -
3
2
3
-
(CdCH
2
2
2
IR (KBr): [cm 1] ) 3365 (O-H), 3134, 3104, 3019 (ar C-H),
2990 (aliph C-H), 2760, 2675, 2609 (pyr O-H), 1715 (CdO),
1635, 1605, 1580, 1522 (CdC, CdN), 1189 (C-OR) and 1696,
1474, 1454, 1405, 1328, 1298, 1205, 965, 953, 791, 759.
+
6
3.00 (N -CH
2
3
-
1
IR (KBr): [cm ] ) 3321 (br, O-H), 3063, 3004 (ar C-H),
730, 2610, 2470 (pyr O-H), 1714 (CdO), 1635, 1589, 1512
2
+
+
(
9
CdC, CdN), 1168 (C-OR) and 1460, 1310, 1252, 1127, 1032,
MS (FD): m/e (%) ) 288 (40) [M - Cl], 287 (100) [M
HCl].
4
Anal. Calcd for C16H18NO Cl (323.77): C, 59.36; H, 5.60; N,
-
57, 812, 686.
MS (FD): m/z (%) ) 238 (42) [M+ - Cl], 237 (100) [M+
-
HCl], 151 (47).
4.33; (O), 19.77; Cl, 10.95. Found: C, 58.68; H, 5.31; N, 4.35;
(O), 20.80; Cl, 10.86.
N-Ben zyl-4-h ydr oxyisoqu in olin iu m Ch lor ide (1b). Ben-
N-Ben zyl-5-h ydr oxyisoqu in olin iu m Ch lor ide (3b). 5-Hy-
droxyisoquinoline (0.50 g, 3.4 mmol) and benzyl chloride (0.44
g, 3.4 mmol) were dissolved in dry ethanol (20 mL) and stirred
for 4 days at room temperature. The solvent was evaporated
and the remaining orange-red solid was purified by flash
chromatography (methanol). Yield: 660 mg (70%), red solid.
zyl chloride (300 mg, 2.4 mmol) was added to a solution of
4-hydroxyisoquinoline2
2,23
(350 mg, 2.4 mmol) in DMF (7 mL).
The orange solution was stirred for 72 h at room temperature,
poured into water (100 mL), and extracted four times with
dichloromethane (15 mL). The combined organic layers were
washed twice with water, dried over magnesium sulfate, and
evaporated. The residue was purified by flash chromatography
(ethyl acetate/methanol, 1:1). Yield: 360 mg (55%), light yellow
Mp: 132-134 °C.
1
H NMR (DMSO-d ): δ [ppm] ) 9.67 (s, 1H, H-1), 8.39 (d,
6
1
7
J
H, J 3,4 ) 6.3 Hz, H-3), 8.18 (d, 1H, J 3,4 ) 6.3 Hz, H-4), 7.67-
.40 (m, 6H, ar-H, H-7), 6.93 (d, J 6,7 ) 7.3 Hz, H-6), 6.73 (d,
7,8 ) 8.3 Hz, H-8), 5.76 (s, 2H, CH
2
).
solid. Mp: 144-147 °C.
-
1
1
IR (KBr): [cm ] ) 3060, 3038 (ar C-H), 2959, 2897 (aliph
6
H NMR (DMSO-d ): δ [ppm] ) 9.50 (s, 1H, H-3), 8.27 (d,
C-H), 2790, 2730, 2610, 2589, 2557 (pyr O-H), 1636, 1603,
1
1
1H, J 7,8 ) 7.8 Hz, H-8), 8.17 (d, 1H, J 5,6 ) 8.3 Hz, H-5), 7.98-
7.81 (m, 2H, H-6, H-7), 7.70 (s, 1H, H-1), 7.50-7.37 (m, 5H,
ar-H), 5.69 (s, 2H, CH ).
2
587 (CdC, CdN), 749, 717 (ar out of plane), and 1458, 1394,
353, 1285, 1036, 890, 798.

4
260 G o¨ rtz and Ritter
13C NMR (DMSO-d
Macromolecules, Vol. 35, No. 11, 2002
6
): δ [ppm] ) 153.54 (C-4), 140.37,
g, 40 mmol) and some hydroquinone in dry ethanol (50 mL)
was stirred for 19 h. After the removal of the solvent, the oily,
greenish residue crystallized during drying in a vacuum. The
product was purified by flash chromatography (ethyl acetate/
methanol, 1:2), which had to be done quickly as the product
slowly hydrolyzed to N-(1,2-hydroxypropyl-3)-3-oxypyridinium
betaine on the silica gel column. Yield: 7.4 g (78%), light green
solid. Mp: 143-146 °C.
1
34.12, 131.47, 126.50, 121.86, 118.49 (C-1, C-3, C-5, C-6, C-7,
), 129.91, 129.39 (C-9, C-10), 129.18,
27.99, 126.95 (ar-CH), 63.47 (CH ).
IR (KBr): [cm ] ) 3061, 3031 (ar C-H), 2958, 2873 (aliph
C-8), 135.26 (ar-C-CH
1
2
2
-
1
C-H), 2550 (pyr O-H), 1679, 1637, 1600, 1581 (CdC, CdN),
7
1
53, 706 (ar C-H out of plane) and 1471, 1456, 1416, 1379,
286, 1131, 1074.
MS (FD): m/z (%) ) 236 (12) [M+ - Cl], 235 (100) [M+
-
1
H NMR (DMSO-d ): δ [ppm] ) 7.34-7.18 (m, 3H, H-2, H-6,
6
HCl].
H-5), 6.85 (d, 1H, J 4,5 ) 8.3 Hz, H-4), 6.12 (s, 1H, CdCHH ),
cis
N-Vin ylben zyl-4-h ydr oxyisoqu in olin iu m Ch lor ide (1a).
N-Vinylbenzyl-4-hydroxyisoquinolinium chloride (1a ) was pre-
pared similarly to 1b using 4-hydroxyisoquinoline
6.04 (br s, 1H, CH-OH), 5.70 (s, 1H, CdCHHtrans), 4.34 (d,
+
1H, J
gem
) 9.8 Hz, CHH -O), 4.08 (br s, 4H, N -CH , CH-
a
2
2
2,23
(2.50 g,
OH, CHH -O), 1.89 (s, 3H, CH ).
b
3
1
7 mmol) and vinylbenzyl chloride (2.60 g, 17 mmol) and
13C NMR (DMSO-d ): δ [ppm] ) 170.45 (C-3), 169.45 (Cd
O), 138.53, 137.21, 129.71, 129.35 (C-2, C-4, C-5, C-6), 136.06
6
adding some hydroquinone. Yield: 2.18 g (49%), light yellow
solid. Mp: 133-135 °C.
(CdCH ), 128.06 (CdCH ), 70.91 (CH-OH), 67.99 (CH -O),
2
2
2
1
+
H NMR (DMSO-d
6
): δ [ppm] ) 13.06 (br s, 1H, OH), 9.77
65.74 (N -CH ), 19.64 (CH ).
2
3
(
s, 1H, H-3), 8.37 (d, 1H, J 7,8 ) 8.8 Hz, H-8), 8.28 (d, 1H, J 5,6
IR (KBr): [cm-1] ) 3300 (vbr, O-H), 3050 (ar C-H), 2960,
)
7
1
7.8 Hz, H-5), 8.13-7.98 (m, 2H, H-6, H-7), 7.72 (s, 1H, H-1),
2
929 (aliph C-H), 1716 (CdO), 1637, 1594, 1568, 1502 (CdC,
.51-7.38 (m, 4H, ar-H), 6.70 (dd, 1H, J cis ) 11.2 Hz, J trans
)
CdN), 1169 (C-OR) and 1456, 1365, 1027, 950, 813, 772, 685.
+
8.1 Hz, CHdCH
2
), 5.89 (s, 2H, N -CH
2
), 5.83 (d, J trans ) 18.1
+
+
2
], 238
MS (FD): m/z (%) ) 476 (21) [M
2
H ], 475 (100) [M
Hz, CHdCHHtrans), 5.27 (d, J cis ) 11.2 Hz, CHdCHHcis).
+
+
(
12) [MH ], 237 (2) [M ].
1
3
C NMR (DMSO-d
33.67, 131.31, 126.18, 121.84, 118.46 (C-1, C-3, C-5, C-6, C-7,
C-8), 137.95 (ar-C-CHdCH ), 135.79 (CHdCH ), 135.20 (ar-
C-CH ), 129.89, 129.38 (C-9, C-10), 129.14, 127.96, 126.73 (ar-
CH), 115.49 (CHdCH
MS (FD): m/z (%) ) 523 (14) [M
6
): δ [ppm] ) 153.55 (C-4), 140.29,
Anal. Calcd for C12
H
15NO (237.26): C, 60.75; H, 6.37; N,
4
1
5
.90; (O), 26.97. Found: C, 60.56; H, 6.47; N, 6.02; (O), 26.95.
N-Ben zyl-3-oxyp yr id in iu m Beta in e (2i). An ion ex-
change column (100 mL ion-exchange resin Amberlite IRA-
10, Cl -form) was activated with 4 N aqueous sodium
hydroxide solution and washed neutral with water. A solution
of N-benzyl-3-hydroxypyridinium chloride (3.00 g, 13 mmol)
in water (30 mL) was brought onto the column and eluted with
water (300 mL). After removal of the solvent, the residue
crystallized during drying in a vacuum. Yield: 2.7 g (98%),
2
2
2
+
2
), 64.82 (N -CH
2
).
-
4
+
+
2
2
H
- 2HCl], 522 (18) [M
+
+
-
2HCl], 262 (21) [M - Cl], 261 (100) [M - HCl].
N-Ben zyl-8-h yd r oxyqu in olin iu m Ch lor id e (4b). A solu-
tion of 8-hydroxyquinoline (4.00 g, 27 mmol) and benzyl
chloride (3.40 g, 27 mmol) in ethanol (30 mL) was stirred for
5
the remaining red, viscous oil crystallized from ethanol/ethyl
acetate. Yield: 1.7 g (23%), yellow solid. Mp: 164-166 °C.
days at room temperature. The solvent was evaporated, and
monohydrate, colorless hygroscopic crystals. Mp: 102-105 °C
26
(
lit.: 107-111 °C).
1
H NMR (DMSO-d ): δ [ppm] ) 7.52-7.37 (m, 7H, ar-H,
6
1
H NMR (DMSO-d ): δ [ppm] ) 12.38 (s, 1H, OH), 9.57 (d,
6
H-2, H-6), 7.25 (dd, 1H, J 5,6 ) 5.4 Hz, J 4,5 ) 9.3 Hz, H-5), 6.88
dd, 1H, J 2,4 ) 1.9 Hz, J 4,5 ) 9.3 Hz, H-4), 5.36 (s, 2H, CH ).
): δ [ppm] ) 169.03 (C-3), 135.44 (ar-
), 133.57, 132.68, 126.85, 120.79 (C-2, C-4, C-5, C-6),
28.71 (ar-CH-para), 128.87, 128.19 (ar-CH-ortho, ar-CH-
meta), 62.13 (CH ).
Anal. Calcd for C12
N, 6.89; (O), 15.74; Found: C, 71.00; H, 6.78; N, 6.91; (O),
5.31.
N-Vin ylben zyl-3-oxyp yr id in iu m Beta in e (2j). N-Vinyl-
benzyl-3-oxypyridinium betaine (2j) was prepared similar to
i using N-vinylbenzyl-3-hydroxypyridinium chloride. It was
1
H, J 2,3 ) 6.0 Hz, H-2), 9.25 (d, 1H, J 3,4 ) 8.3 Hz, H-4), 9.01
(
2
(
8
7
d, 1H, J 6,7 ) 6.8 Hz, H-7), 8.14 (dd, 1H, J 2,3 ) 6.0 Hz, J 3,4
)
.3 Hz, H-3), 8.03 (dd, 1H, J 6,7 ) 6.8 Hz, J 5,6 ) 8.8 Hz, H-6),
.88-7.66 (m, 4H, ar-H), 7.40 (d, 1H, J 5,6 ) 8.8 Hz, H-5), 6.62
1
3
C NMR (DMSO-d
C-CH
6
2
1
2
(s, 2H, CH ).
IR (KBr): [cm-1] ) 3297 (O-H), 3043, 3009 (ar C-H), 2948,
886 (aliph C-H), 2671, 2616, 2549 (pyr O-H), 1594, 1550,
497 (CdC, CdN), 738, 697 (ar C-H out of plane) and 1452,
378, 1368, 1319, 1312, 1247, 1158, 1133, 838, 815, 760.
2
H
2
11NO‚H O (203.23): C, 70.92; H, 6.44;
2
1
1
1
+
+
MS (FD): m/z (%) ) 236 (21) [M - Cl], 235 (100) [M
HCl].
Anal. Calcd for C16
.15; (O), 5.89; Cl, 13.05. Found: C, 69.84; H, 4.70; N, 5.45;
O), 6.24; Cl, 13.77.
N-Vin ylben zyl-8-h yd r oxyqu in olin iu m Ch lor id e (4a ).
-
2
H
14NOCl (271.74): C, 70.91; H, 5.19; N,
dried to constant weight under reduced pressure but failed to
crystallize. Yield: quantitative if regarded as the monohydrate,
colorless very hygroscopic viscous oil.
5
(
1
H NMR (DMSO-d ): δ [ppm] ) 7.60-7.35 (m, 6H, ar-H,
6
N-Vinylbenzyl-8-hydroxyquinolinium chloride (4a ) was pre-
pared similarly to 4b using 8-hydroxyisoquinoline (4.00 g, 27
mmol) and vinylbenzyl chloride (4.1 g, 27 mmol) and adding
hydroquinone. The product crystallized on addition of a grain
of 4b. Yield: 2.20 g (27%), orange crystals. Mp: 129-132 °C.
H-2, H-6), 7.24 (dd, 1H, J 5,6 ) 5.4 Hz, J 4,5 ) 8.8 Hz, H-5), 6.86
dd, 1H, J 2,4 ) 2.4 Hz, J 4,5 ) 8.8 Hz, H-4), 6.72 (dd, 1H, J cis
(
1
)
1.2 Hz, J trans ) 17.6 Hz, CHdCH
2
), 5.85 (d, 1H, J trans ) 17.6
), 5.28 (dd, 1H, J gem ) 3.9
Hz, CHdCHHtrans), 5.33 (s, 2H, CH
Hz, J cis ) 11.2 Hz, CHdCHHcis).
2
1
H NMR (DMSO-d
6
): δ [ppm] ) 12.39 (s, 1H, OH), 9.58 (d,
-
1
1
H, J 2,3 ) 5.9 Hz, H-2), 9.23 (d, 1H, J 3,4 ) 8.3 Hz, H-4), 9.08
IR (KBr): [cm ] ) 3391 (br, O-H), 3088, 3064 (ar C-H),
(
8
7
d, 1H, J 6,7 ) 6.8 Hz, H-7), 8.13 (dd, 1H, J 2,3 ) 5.9 Hz, J 3,4
)
.3 Hz, H-3), 8.03 (dd, 1H, J 6,7 ) 6.8 Hz, J 5,6 ) 8.8 Hz, H-6),
.89-7.65 (m, 4H, ar-H), 7.39 (d, 1H, J 5,6 ) 8.8 Hz, H-5), 6.67
2980 (aliph C-H), 1589, 1566, 1505 (CdC, CdN), 993, 917
2
(CHdCH out of plane), 832, 765 (ar C-H out of plane) and
1649, 1462, 1371, 1342, 1029.
(
2
5
dd, 1H, J cis ) 11.2 Hz, J trans ) 17.6 Hz, CHdCH
2
), 6.60 (s,
), 5.79 (d, 1H, J trans ) 17.6 Hz, CHdCHHtrans),
.23 (d, 1H, J cis ) 11.2 Hz, CHdCHHcis).
N-(2-H yd r oxy-1-m et h a cr yloyloxyp r op yl-3)-5-oxyiso-
qu in olin iu m Beta in e (3c). N-(2-Hydroxy-1-methacryloyloxy-
propyl-3)-5-oxyisoquinolinium betaine (3c) was prepared simi-
lar to 2c reacting glycidyl methacrylate (7 mmol) with 5-hy-
droxyisoquinoline (7 mmol) in ethanol (30 mL) for 42 h. The
crude dark red product was purified by flash chromatography
(methanol). A slow hydrolysis of the product started on the
silica gel column. Yield: 0.9 g (45%), orange red solid. Mp:
+
H, N -CH
2
-1
IR (KBr): [cm ] ) 3270 (O-H), 3043 (ar C-H), 2991 (aliph
2
C-H), 1595, 1546, 1516 (CdC, CdN), 995, 916 (CHdCH out
of plane), and 1460, 1362, 1307, 1247, 1200.
+
- 2HCl], 262 (24) [M+
-
MS (FD): m/z (%) ) 523 (9) [M
2
+
Cl], 261 (100) [M - HCl].
Anal. Calcd for C18
H
16NOCl (297.78): C, 72.60; H, 5.41; N,
162-165 °C.
1
4
.70; (O), 5.37; Cl, 11.90. Found: C, 71.71; H, 5.06; N, 4.63;
6
H NMR (DMSO-d ): δ [ppm] ) 9.30 (s, 1H, H-1), 8.26 (d,
(O), 6.68; Cl, 11.92.
1H, J 3,4 ) 6.8 Hz, H-3), 8.02 (d, 1H, J 3,4 ) 6.8 Hz, H-4), 7.42
Syn th esis of th e Beta in es. N-(2-Hyd r oxy-1-m eth a cr yl-
(dd, 1H, J 6,7 ) 7.8 Hz, J 7,8 ) 8.3 Hz, H-7), 6.78 (d, 1H, J 6,7 )
oxyp r op yl-3)-3-oxyp yr id in iu m Beta in e (2c). A solution of
-hydroxypyridine (3.8 g, 40 mmol), glycidyl methacrylate (5.6
7.8 Hz, H-6), 6.55 (d, 1H, J 7,8 ) 8.3 Hz, H-8), 6.14 (s, 1H, Cd
CHHcis), 5.73 (s, 1H, CdCHHtrans), 4.70 (d, 1H, J gem ) 13.0 Hz,
3

Macromolecules, Vol. 35, No. 11, 2002
New Photosensitive Polymers 4261
+
+
N -CHH
a
), 4.38 (d, 1H, J gem ) 13.0 Hz, N -CHH
-O), 1.91 (s, 3H, CH ).
C NMR (DMSO-d ): δ [ppm] ) 169.52 (CdO), 167.42 (C-
), 151.46, 138.51, 134.46, 124.87, 123.58, 114.80 (C-1, C-3,
), 132.55, 132.10 (C-9, C-10),
), 70.72 (CH-OH), 68.11 (CH -OH), 65.68
), 19.61 (CH ).
b
), 4.20 (m,
1491 (CdC, CdN), 807, 761 (ar C-H out of plane), and 1449,
1310, 1259, 1147, 1032, 872, 707, 684.
3
H, CH-OH, CH
2
3
1
3
6
P oly[N-(2-h yd r oxy-1-m eth a cr yloyloxyp r op yl-3)-3-h y-
d r oxyp yr id in iu m ch lor id e] (2f). Monomer: 2d . Solvent:
DMF. Initiator: AIBN. Precipitation polymerization: no fur-
ther polymer could be isolated from the solvent. The obtained
polymer was dissolved in a small amount of water, reprecipi-
tated in 2-propanol, redissolved in water, and freeze-dried.
5
C-4, C-6, C-7, C-8), 136.03 (CdCH
28.07 (CdCH
2
1
2
2
+
(
N -CH
2
3
-
1
IR (KBr): [cm ] ) 3027 (ar C-H), 2960, 2926, 2884 (aliph
C-H), 1716 (CdO), 1633, 1573, 1503, (CdC, CdN), 1160 (C-
Yield: 92% colorless solid.
1
OR) and 1470, 1454, 1417, 1388, 1337, 1321, 1255, 1118, 1027,
2
H NMR (D O): δ [ppm] ) 8.25 (br s, 2H, H-2, H-6), 7.81
+
9
53, 938, 851, 784, 750, 741.
MS (FD): m/z (%) ) 288 (12) [MH ], 287 (100) [M ].
Anal. Calcd for C16 (287.31): C, 66.89; H, 5.96; N,
.87; (O), 22.27. Found: C, 65.75; H, 5.84; N, 5.07; (O), 23.34.
N-Ben zyl-5-oxyisoqu in olin iu m Beta in e (3i). N-Benzyl-
-oxyisoquinolinium betaine (3i) was prepared similar to 2i
(br s, 2H, H-4, H-5), 4.33-4.80 (br m, 5H, N -CH
CH -O), 1.92 (br s, 2H, CH -C), 1.16 (s, isot-CH
heterot-CH ), 0.83 (s, syndiot-CH ).
IR (KBr): [cm- ] ) 3332 (O-H), 3062 (ar C-H), 2958 (aliph
C-H), 2750, 2628, 2500 (pyr O-H), 1728 (CdO), 1604, 1587,
1498 (CdC, CdN), 1161 (aliph C-OR) and 1456, 1319, 1274,
1123, 1031, 807, 685.
2
, CH-OH,
), 0.99 (s,
+
+
2
2
3
H
17NO
4
3
3
1
4
5
and 2j using N-benzyl-5-hydroxyisoquinolinium chloride.
Yield: 80% dihydrate, red violet solid. Mp: 91 °C.
P oly[N-(2-h yd r oxy-1-m eth a cr yloyloxyp r op yl-3)-5-h y-
d r oxyisoch in olin iu m ch lor id e] (3f). Monomer: 3d . Sol-
vent: DMF. Initiator: AIBN. The polymer was precipitated
in 2-propanol, filtered off, and dried to constant weight under
1
H NMR (DMSO-d ): δ [ppm] ) 9.57 (s, 1H, H-1), 8.33 (d,
6
1
7
(
H, J 3,4 ) 6.5 Hz, H-3), 8.07 (d, 1H, J 3,4 ) 6.5 Hz, H-4), 7.52-
.37 (m, 6H, ar-H, H-7), 6.74 (d, 1H, J 6,7 ) 7.8 Hz, H-6), 6.54
d, 1H, J 7,8 ) 8.3 Hz, H-8), 5.70 (s, 2H, CH
2
).
): δ [ppm] ) 167.92 (C-5), 147.49,
34.00, 127.83, 123.41, 119.42, 105.10 (C-1, C-3, C-4, C-6, C-7,
), 131.91, 130.35 (C-9, C-10), 129.04,
28.43 (ar-CH-ortho, ar-CH-meta), 128. 91 (ar-CH-para), 62.25
reduced pressure. Yield: 92% light yellow solid.
1
3
1
C NMR (DMSO-d
6
6
H NMR (DMSO-d ): δ [ppm] ) 11.45 (br s, 1H, OH), 9.93
1
(br s, 1H, H-1), 8.63 (br s, 1H, H-3), 8.01 (br s, 1H, H-8), 7.45
C-8), 139.8 (ar-C-CH
2
(br s, 3H, H-4, H-6, H-7), 6.13 (br s, OH), 4.89-3.99 (br m,
+
1
5H, N -CH
2
, CH-OH, CH
).
2
-O), 2.07 (br s,2H, CH -C); 1.00
2
(
CH
2
).
(br s, 3H, CH
3
IR (KBr): [cm-1] ) 3108, 3062, 3029 (ar C-H), 1623, 1579,
503 (CdC, CdN), 742, 716 (ar C-H out of plane) and 1474,
460, 1425, 1383, 1342, 1309, 1181, 1093, 853, 784.
IR (KBr): [cm-1] ) 3391 (O-H), 3100 (ar C-H), 2730, 2615,
2520 (pyr O-H), 1728 (CdO), 1657, 1605, 1582, 1520 (CdC,
CdN), 1185, 1155 (C-O) and 1475, 1449, 1400, 1297, 1249,
1119, 798, 759.
1
1
+
+
MS (FD): m/z (%) ) 236 (23) [MH ], 235 (100) [M ].
Anal Calcd for C16 13NO‚2H O (271.31): C, 70.83; H, 6.31;
N, 5.16; (O), 17.69. Found: C, 70.26; H, 6.72; N, 5.05; (O),
H
2
P oly[N-vin ylb en zyl-4-h yd r oxyisoch in olin iu m ch lo-
r id e] (1e). Monomer: 1a . Solvent: water/acetonitrile (2:1).
Initiator: potassium peroxodisulfate. Precipitation polymer-
ization: further polymer was isolated from the solvent by
precipitation in 2-propanol. After reprecipitation, the polymer
was dried to constant weight under reduced pressure. Yield:
1
7.97.
N-Ben zyl-4-oxyisoqu in olin iu m Beta in e (1i). N-Benzyl-
4
2
-oxyisoquinolinium betaine (1i) was prepared similar to 2i,
j, and 3i using N-benzyl-4-hydroxyisoquinolinium chloride.
Yield: 72% dodecahydrate, yellow solid. Mp: 85-87 °C.
69% light yellow solid.
1
1
H NMR (DMSO-d
6
): δ [ppm] ) 8.16 (ddd, 1H, J meta ) 2.4
6
H NMR (DMSO-d ): δ [ppm] ) 7.62-7.20 (br m, 6H, H-1,H-
+
Hz, J ortho ) 6.8 Hz, J ortho ) 9.3 Hz, H-6/H-7), 7.90 (ddd, 1H,
3, H-5-8), 6.98-6.51 (br m, 4H, ar-H), 4.12 (br s, 2H, N -
CH ), 1.93 (br s, 3H, CH -CH, CH -CH).
J
7
meta ) 2.3 Hz, J ortho ) 6.8 Hz, J ortho ) 9.3 Hz, H-6/H-7), 7.63-
.48 (m, 4H, H-1, H-3, H-5, H-8), 7.40-7.37 (m, 5H, ar-H), 7.19
2
2
2
-1
IR (KBr): [cm ] ) 3025 (ar C-H), 2950, 2840 (aliph C-H),
2502 (pyr O-H), 1692, 1602 (CdC, CdN), 766 (ar C-H out of
plane), and 1458, 1138, 1127, 1108, 1023.
(s, 2H, CH
2
).
C NMR (DMSO-d
C-CH ), 134.56, 129.53, 127.52, 126.93, 123.68, 119.83 (C-1,
C-3, C-5, C-6, C-7, C-8), 129.3, 129.01 (C-9, C-10), 128.83,
28.19 (ar-CH-ortho, ar-CH-meta), 128.70 (ar-CH-para), 62.26
1
3
6
): δ [ppm] ) 167.15 (C-4), 135.47 (ar-
2
Cop olym er iza tion P r oced u r e. P oly[N-vin ylben zyl-3-
h yd r oxyp yr id in iu m ch lor id e-co-styr en e] (2g). In a typical
polymerization, the monomer N-(vinylbenzyl)-3-hydroxypyri-
dinium chloride (2a , 198 mg, 0.8 mmol), the comonomer
styrene (417 mg, 4 mmol, 5 equiv), sodium chloride (24 mg,
0.4 mmol, 0.5 equiv), and the initiator AIBN (16 mg, 96 µmol,
2 mol %) were dissolved in acetonitrile (4 mL, 15 wt % solution
based on the monomers) and the solution degassed with
nitrogen. The polymerization flask was sealed and put for 24
h into a bath preheated to 60-62 °C. The polymer precipitated
during the reaction. Dropping of the supernatant into 2-pro-
panol yielded no further precipitate. The polymer was dis-
solved in a small amount of DMSO, reprecipitated in 2-pro-
panol, filtered off, and dried to constant weight under reduced
1
(
2
CH ).
IR (KBr): [cm-1] ) 3059 (ar C-H), 2958 (aliph C-H), 1568,
502 (CdC, CdN), 750, 704 (ar C-H out of plane) and 1487,
454, 1345, 1132, 882.
1
1
+
+
M+ S (FD): m/z (%) ) 470 (4) [M
M ].
Anal Calcd for C16
N, 3.10; (O), 46.07. Found: C, 43.05; H, 8.07; N, 3.08; (O),
5.80.
P olym er iza tion Rea ction s. Hom op olym er iza tion P r o-
2
], 236 (11) [MH ], 235 (100)
[
H
2
13NO‚12 H O (451.46): C, 42.57; H, 8.26;
4
ced u r e. P oly[N-vin ylben zyl-3-h yd r oxyp yr id in iu m ch lo-
r id e] (2e). In a typical polymerization the monomer N-(vi-
nylbenzyl)-3-hydroxypyridinium chloride (2a , 495 mg, 2 mmol),
sodium chloride (580 mg, 1 mmol, 0.5 equiv), and the initiator
potassium peroxodisulfate (11 mg, 40 µmol, 2 mol %) were
dissolved in water (3 mL, 15 wt % solution based on the
monomer), and the solution was degassed with nitrogen. The
polymerization flask was sealed and put for 24 h into a bath
preheated to 60-62 °C. The polymer was precipitated by
dropping the solution into 2-propanol. After filtration, the
polymer was dissolved in water and freeze-dried. Yield: 75%,
pressure. Yield: 69% colorless solid.
1
H NMR (DMSO-d ): δ [ppm] ) 8.87 (br s, 4H, H-2,H-4,
6
H-5, H-6), 8.18-7,95 (br m, 4H, ar-H[salt]), 7.43-6.15 (br m,
+
25H, 5*(ar-H[styrene])), 5.79 (br s, 2H, N -CH
18H, CH -CH[salt], CH -CH[salt], 5*(CH -CH[styrene], CH
CH[styrene])).
2
), 1.54 (br s,
2
2
2
2
-
IR (KBr): [cm-1] ) 3385 (O-H), 3020 (ar C-H), 2921, 2849
(aliph C-H), 2725, 2603, 2500 (pyr-OH), 1601, 1583, 1509,
1492 (CdC, CdN), 807, 761, 702 (ar C-H out of plane), and
1451, 1311, 1259, 1147, 1030, 684.
colorless solid.
P oly[N-(2-h yd r oxy-1-m eth a cr yloyloxyp r op yl-3)-3-h y-
d r oxyp yr id in iu m ch lor id e-co-m eth yl m eth a cr yla te] (2h ).
Monomer: 2d . Comonomer: MMA. Solvent: DMF. Initiator:
AIBN. No precipitation of polymer during polymerization. The
polymer obtained by precipitation in 2-propanol was dissolved
in water and freeze-dried. Yield: 66% colorless solid.
1
H NMR (D O): δ [ppm] ) 8.24 (br s, 2H, H-2, H-6), 7.66
2
(
2
br s, 2H, H-4, H-5), 6.98-6.24 (br m, 4H, ar-H), 5.38 (br s,
+
H, N -CH
IR (KBr): [cm ] ) 3387 (O-H), 3024 (ar C-H), 2926, 2853
aliph C-H), 2729, 2613, 2506 (pyr O-H), 1603, 1584, 1509,
2
), 1.23 (br s, 3H, H-14, CH
2
-CH, CH
2
-CH).
-1
(

4
262 G o¨ rtz and Ritter
Macromolecules, Vol. 35, No. 11, 2002
Sch em e 2
Sch em e 3
Treatment of 3-hydroxypyridine (2) and 5-hydroxy-
isoquinoline (3) with glycidyl methacrylate yielded N-(2-
hydroxy-1-methacryloyloxypropyl-3)-3-oxypyridinium be-
taine (2c) and N-(2-hydroxy-1-methacryloyloxypropyl-
1H NMR (D
H-4, H-5), 4.34-4.09 (br m, N -CH
br s, O-CH ), 1.87 (br s, CH -C[salt], CH
.79 (br m, CH [salt], CH [MMA]).
O): δ [ppm] ) 8.28 (br s, H-2, H-6), 7.81 (br s,
2
+
2
, CH-OH, CH
2
-O), 3.55
(
0
3
2
2
-C[MMA]), 1.2-
3
3
3
)-5-oxyisoquinoline betaine (3c). They were converted
-1
IR (KBr): [cm ] ) 3067 (ar C-H), 2997, 2951 (aliph C-H),
750, 2629, 2500 (pyr O-H), 1727 (CdO), 1604, 1587, 1499
into the quaternary salts 2d and 3d upon treatment
2
with hydrochloric acid (Scheme 3).
(CdC, CdN), 1191, 1157 (C-OR) and 1450, 1321, 1276, 1031,
Free radical homopolymerizations of the N-quater-
nary salts 1a , 2a , 2d , and 3d in polar solvents (water,
water/acetonitrile or DMF) with potassium peroxodis-
ulfate or AIBN as initiator and sodium chloride as a
low molecular weight salt resulted in the ionic ho-
mopolymers 1e, 2e, 2f, and 3f (Scheme 4). The poly-
electrolytes 2e and 2f consisting of the 3-hydroxypyri-
dinium chloride derivatives were soluble in water, as
expected.
Copolymerization of the styrene based quaternary
salts 1a and 2a with styrene and of the methacryloyl
based salts 2d and 3d with MMA in a molar ratio of
1:5 respectively was realized as described above. From
the obtained copolymers 1g, 2g, 2h , and 3h (Scheme 5)
the N-methacryloyl based 3-hydroxypyridinium chloride/
MMA copolymer 2h showed good solubility in water.
8
07, 686.
P oly[N-(2-h yd r oxy-1-m eth a cr yloyloxyp r op yl-3)-5-h y-
d r oxyisoch in olin iu m ch lor id e -co-m eth yl m eth a cr yla te]
3 h ). Monomer: 3d . Comonomer: MMA. Solvent: DMF.
(
Initiator: AIBN. Precipitation polymerization: no further
polymer could be isolated from the solvent. Yield: 74% light
yellow solid.
1H NMR (DMSO-d
br s, H-1), 8.63 (br s, H-3), 8.01 (br s, H-8), 7.45 (br s, H-4,
): δ [ppm] ) 11.45 (br s, hetar-OH), 9.93
6
(
+
2
H-6, H-7), 6.13 (br s, CH-OH), 4.89-3.99 (br m, N -CH ,
CH-OH, CH
O-CH ), 2.07 (br s, CH
CH [salt], CH [MMA]).
2
-O),3.34 (br s, H
2
O in DMSO-d
6
superimposed
3
2
-C[salt], CH
2
-C[MMA]), 1.00 (br s,
3
3
IR (KBr): [cm 1] ) 3348 (O-H), 3100 (ar C-H), 2952 (aliph
-
C-H), 2731, 2616, 2521 (pyr O-H), 1727 (CdO), 1644, 1605,
1
1
581, 1520 (CdC, CdN), 1185, 1155 (C-OR) and 1475, 1449,
400, 1296, 798, 758.
P oly[N-vin ylben zyl-4-h ydr oxyisoch in olin iu m ch lor ide-
To evaluate the exact copolymer compositions, well-
defined integrated signals of the incorporated comono-
mers styrene (aromatic protons at 7.4-6.1 ppm) or
MMA (O-CH3 protons at 3.55 ppm) were compared to
the area of the signals of the corresponding quaternized
hydroxy N-heterocyle (benzylic protons at 8.18-7.95
co-styr en e] (1 g). Monomer: 1a . Comonomer: styrene.
Solvent: water/acetonitrile (1:2). Initiator: AIBN. Precipita-
tion polymerization: further polymer was isolated from the
solvent. Yield: 75%, light yellow solid.
1
H NMR (DMSO-d ): δ [ppm] ) 7.65-7.20 (br m, H-1, H-3,
6
H-5-8), 7.13-6.05 (br m, ar-H[salt and styrene]), 4.12 (br s,
1
+
ppm) in the H NMR spectra. In correspondence to the
N -CH
2
), 2.1-0.93 (br m, CH
2
-CH, CH -CH[salt and sty-
2
rene]).
initial molar ratio used, a proportion of incorporated
styrene units to incorporated N-vinylbenzyl-3-hydroxy-
pyridinium chloride units of 5:1 was found for copolymer
IR (KBr): [cm-1] ) 3081, 3059, 3025 (ar C-H), 2922, 2848
aliph C-H), 1694, 1601,1583, 1493 (CdC, CdN), 758, 698 (ar
(
C-H out of plane) and 1452, 1370, 1306, 1291, 1028, 907.
2
g. The nonconformance of the integration due to the
extremely broadened proton signals permitted no exact
evaluation of the other copolymer compositions.
Resu lts a n d Discu ssion
4
-Hydroxyisoquinoline (1) was synthesized accord-
In most cases, the photosensitive dipolar betaine
structure was generated in situ by adding triethylamine
to a solution of the N-quaternary salts immediately
before irradiation.
2
2,23
ing to the literature.
The quaternary N-styrene
substituted salts 1a -4a were prepared from 3-hydroxy-
pyridine (2), 4- and 5-hydroxyisoquinoline (1 and 3),
and 8-hydroxyquinoline (4) using vinylbenzyl chloride
However, the low molecular weight betaines 1i-3i,
and 2j (Scheme 6) were generated as model compounds
by passing the corresponding ammonium salts through
a column filled with basic anionic exchange resin
(
Scheme 2).
The N-benzyl-substituted model compounds 1b-4b
Scheme 2) were obtained following the same procedure
using benzyl chloride instead of vinylbenzyl chloride.
(
-
(Amberlite IRA-410, OH form).

Macromolecules, Vol. 35, No. 11, 2002
New Photosensitive Polymers 4263
Sch em e 4
Sch em e 5
Sch em e 6
within the range of the benzoaromatic proton signals.
The dd signal of H-5 at 7.24 ppm shows a comparably
risen ortho coupling of 8.8 Hz with H-4 (salt 2b: 8.5
Hz) and a lowered ortho coupling of 5.4 Hz with H-6
(
salt 2b: 5.9 Hz).
An early comparative NMR spectroscopic study24 on
the structure of the two likewise uncharged substances
-methoxypyridine and N-methyl-3-oxypyridinium be-
3
1
taine provided comparable changes in the H NMR
spectrum. The enhanced coupling of H-4 and H-5 in the
betaine is explained by increased π-bonding order
between C-4 and C-5. The particularly strong displace-
ment of the R-proton signals to higher fields is at-
tributed to a remarkably risen electron density at the
R-carbons of the betaine. These conclusions are con-
firmed by PPP-MO calculations of total π-electron
densities. While for 3-methoxypyridine electron density
is reduced at the R-carbons, it is enhanced there for the
1
Ta ble 1. H NMR (200 MHz) Ch em ica l Sh ifts a n d
Cou p lin g Con sta n ts of Heter oa r om a tic P r oton s in
Oxyp yr id in iu m Der iva tives 2b a n d 2j
2
4
betaine.
By means of N-benzyl-4-oxyisochinolinium betaine
1i) in Figure 1, the similar distribution in the HOMO
(
of the betaines is exemplified. The high orbital coef-
ficients at C-2 and C-6 combined with the comparable
high HOMO energy (EHOMO ) -4.98 eV, calculated by
the DFT, pBP/DN* method implemented in PC Spartan
Pro 1.07) and the opposite sign of the orbital coefficients
explains their reactivity in thermal 1,3-dipolar cycload-
ditions with electron deficient olefins. In the corre-
sponding LUMO (Figure 1) the size of the orbital
coefficients at C-2 and C-6 remains nearly the same.
The same sign of the orbital coefficients enables the
betaines to form aziridines (e.g., Scheme 1) via photo-
chemical induced disrotatory intramolecular ringclo-
sure.
1H and 13C NMR measurements documented a dis-
tinct change of electron density and distribution from
the cationic hydroxyl N-quaternized structure to the
1
highly dipolar betaine. In the 200 MHz H NMR
spectrum of N-benzyl-3-hydroxypyridinium chloride (2b)
the signals of the protons in R-position to the heteroaro-
matic nitrogen appear at highest frequencies (Table 1).
1
The corresponding 200 MHz H NMR spectrum of
N-vinylbenzyl-3-oxypyridinium betaine (2j) exhibits
proton signals of the now overall uncharged dipolar
N-heterocycle at comparably higher fields (Table 1).
The strongest displacement to higher magnetic field
is found for the signals of the R-protons which are now
In the UV absorption spectra (10- M in dichlo-
4
romethane), the highest wavelength absorption of the

4
264 G o¨ rtz and Ritter
Macromolecules, Vol. 35, No. 11, 2002
F igu r e 3. Absorption spectra recorded during the irradiation
of copolymer 2h , 10 M in dichloromethane + TEA.
-
4
F igu r e 1. HOMO and LUMO of N-benzyl-4-oxyisochinolinium
betaine (1i) calculated by the DFT, pBP/DN* method imple-
mented in PC Spartan Pro 1.07.
F igu r e 2. Absorption spectra of N-benzyl-3-hydroxypyri-
dinium chloride (2b, dotted line) and its betaine (2i, solid line).
F igu r e 4. Absorption spectra recorded during the irradiation
of salt 2b, 10 M in dichloromethane + TEA.
-
4
Sch em e 7
betaines is always found at remarkably higher wave-
lengths than the one of the corresponding salts, as
shown in Figure 2 for N-benzyl-3-hydroxypyridinium
chloride (2b, λmax ) 305 nm) and its betaine 2i (λmax )
3
65 nm).
The (co)polymers 1e, 2e, 2f, 3f, 1g, 2g, 2h , and 3h
and model salts 1b-4b were irradiated in the presence
-
4
of triethylamine in dichloromethane solution (10 M)
through a Pyrex filter using a xenon high-pressure lamp
(
600 W). The progress of the reaction was regularly
monitored by recording UV absorption spectra. Figure
shows the absorption spectra recorded during irradia-
3
tion of the copolymer poly[N-(2-hydroxy-1-methacryloyl-
oxypropyl-3)-3-hydroxypyridinium chloride-co-methyl
methacrylate] (2h ) in the presence of TEA and Figure
Ta ble 2. Ch a r a cter istic NMR a n d IR Da ta for
Su bsta n ce 1k
4
those of the irradiation of N-benzyl-3-hydroxypyri-
dinium chloride (2b).
The highest wavelength absorption degraded during
irradiation of all model compounds and copolymers.
Besides a further degrading absorption band at around
2
80 nm, which is probably assignable to a higher
energetic transition of the betaine, the spectra of model
compound 2b shown in Figure 4 reveal the formation
of a new absorption at around 300 nm corresponding to
the development of the predicted carbonyl-aziridine type
structure. Yet the copolymer spectra (see the exemplary
spectra of copolymer 2h in Figure 3) do not vary at lower
wavelengths. As the bands are considerably broadened,
it can be assumed that a simultaneous growth and
degradation of two bands in a comparably narrow
wavelength range is not detectable.
In a preliminary quantitative experiment, N-benzyl-
4-hydroxyisoquinolinium chloride (1b) was irradiated
in the presence of triethylamine in dichloromethane.
The formation of the expected aziridine 1-benzyl-1a,6a-

Macromolecules, Vol. 35, No. 11, 2002
New Photosensitive Polymers 4265
dihydroindeno[1,2-b]azirin-6(1H)-one (1k , Scheme 7),
(8) B o¨ hme, F.; Menges, B.; Mittler, S.; Ritter, H.; Theis, A. Chem.
Mater., in press.
(9) Katritzky, A. R.; Rees, C. W.; Scriven In Comprehensive
Heterocyclic Chemistry II, 2nd ed.; Pergamon Press: Oxford,
England, 1996; Vol. 1a.
which was not isolated in pure form, could however be
1
13
confirmed by H NMR, C NMR, and IR spectra (Table
).
2
(
10) Katritzky, A. R.; Rees, C. W. In Comprehensive Heterocyclic
Chemistry, 1st ed.; Pergamon Press: Oxford, England, 1984;
Vol. 2, Part 2A.
Con clu sion
N-Methacryloyl- and N-styrene-substituted hydroxy-
pyridinium and hydroxyisoquinolinium salts readily
form homo- or copolymers by a free radical polymeri-
zation. Polymer-bonded dipolar oxypyridinium and oxy-
isoquinolinium betaines are photosensitive, and for a
model compound the expected aziridine structure was
identified after irradiation. Thus, polymers with oxy-
pyridinium or oxyisoquinolinium groups could poten-
tially be suitable for the development of a new type of
photosensitive material. In subsequent investigations,
new substituted pyridinium and isoquinolinium be-
taines are to be prepared for further variation of
absorption characteristics and physical properties.
(
11) Katritzky, A. R.; Dennis, N. In New Trends in Heterocyclic
Chemistry; Elsevier: New York, 1979.
12) Katritzky, A. R.; Boonyarakvanich, A.; Dennis, N. J . Chem.
Soc., Perkin Trans. 1 1980, 343.
(
(13) Katritzky, A. R.; Rahimi-Rastgoo, S.; Sabongi, G. J . Chem.
Soc., Perkin Trans. 1 1980, 362.
(14) Katritzky, A. R.; Banerji, J .; Dennis, N. J . Chem. Soc., Perkin
Trans. 1 1979, 2528.
(
15) Katritzky, A. R.; Cutler, A. T.; Dennis, N. J . Chem. Soc.,
Perkin Trans. 1 1980, 1176.
(16) Katritzky, A. R.; Dennis, N.; Dowlatshahi, H. A. J . Chem.
Soc., Perkin Trans. 1 1980, 331.
(17) Dennis, N.; Katrizky, A. R.; Wilde, H. J . Chem. Soc., Perkin
Trans. 1 1976, 2339.
(
18) Dennis, N.; Katritzky, A. R.; Takeuchi, Y. J . Chem. Soc.,
Perkin Trans. 1 1972, 2054.
Refer en ces a n d Notes
(
(
19) Garling, D. L.; Cromwell, N. H. J . Org. Chem. 1973, 38, 654.
20) Dennis, N.; Katritzky, A. R.; Parton, S. K. Chem. Pharm. Bull.
(
(
1) Theis, A.; Ritter, H. Des. Monomers Polym. 2001, 4, 177.
2) Heinenberg, M.; Reihmann, M.; Ritter, H. Des. Monomers
Polym. 2000, 3, 501.
1
975, 23, 2899.
21) Hansen, P. E.; Undheim, K. J . Chem. Soc., Perkin Trans. 1
975, 305.
22) Constable, K. P.; Carroll, F. I. Heterocycl. Commun. 1996, 2
1), 13.
(
(
1
(
(
(
(
(
3) Heinenberg, M.; Ritter, H. Macromol. Chem. Phys. 1999, 200,
1
792.
(
4) Ritter, H.; Sperber, R.; Weisshuhn, C. M. Macromol. Chem.
Phys. 1994, 195, 3823.
5) Ritter, H.; Sperber, R. Macromol. Rapid Commun. 1995, 16,
(23) Bacon, R. G. R.; Rennison, S. C. J . Chem. Soc. C 1969, 312.
(24) V o¨ geli, U.; v. Philipsborn, W. Org. Magn. Reson. 1973, 5, 551.
(25) Pham, V. C.; Charlton, J . L. J . Org. Chem. 1995, 60, 8051.
4
07.
6) Deutschmann, T.; Ritter, H. Macromol. Rapid Commun.
995, 17, 723.
7) Gotthardt, H.; Schenk, K. H. J . Chem. Soc., Chem. Commun.
986, 687.
(26) Shapiro, S. L.; Weinberg, K.; Freedman, L. J . Am. Chem. Soc.
1
1
959, 81, 5140.
1
MA011750B