PreparationofHydroquinone-ContainingPolymersbyROMP
J. Chin. Chem. Soc., Vol. 48, No. 5, 2001 947
a tives of benzonorbornadiene. Their av er aged mo lec u lar
weights were tun able, and ran dom co pol y mers were also ac-
cessible.Theirredoxpropertiesareundercurrentinvestiga-
tion, which is ham pered by the for ma tion of low sol u bil ity
precipitates.
u ble in most al kanes and al co hols. IR 1760 (s), 1478 (m),
1361 (m), 1201 (s) 1170 (s) cm-1. 1H NMR (300 MHz, CDCl3)
1.70 & 2.60 (br, 2H to tal, -CH2- for trans and cis iso mers in
ca. 1:1 ra tio), 2.15 (br, 6H, -CH3), 3.77 & 4.17 (br, 2H to tal,
-CH-), 5.56 (br, 2H, =CH-), 6.91 (br, 2H, Ph). 13C NMR (75
MHz, 1Hdecoupled, CDCl3) 20.84 (s, -CH3), 40.3 & 41.6
(m, for cis and trans iso mers), 46.09 (s), 122.10 (br, =CH-),
131.81 (br, Ph), 138.56 & 139.15 (s, Ph), 144.90 & 145.18 (s,
Ph), 168.51 & 169.38 (br, -CO2-).
EXPERIMENTAL
1H and 13C spec tra were ob tained on a Brucker AC-300
spectrometer.Chemicalshiftsof 1H were mea sured down-
field from TMS in units, while those of 13C were re corded
with the cen tral peak of CDCl3 at 77.00asaninternalrefer-
ence. In fra red spec tra were re corded on a Perkin-Elmer 682
infraredspectrophotometer.
Polymerizationof p-dihydoxybenzonorbornadiene 1b
To a round bot tom flask (25 mL) con tain ing MoCl5 (50
mg)underanitrogenatmospherewasaddedfreshlydistilled
THF (2.0 mL). The so lu tion was stirred with a mag netic bar
for 5 min, then to brown so lu tion was in jected through a sy-
ringe SnMe4 (0.070 mL). The so lu tion turned green ish af ter
an other 5 min; to it was added 1b (500 mg), and the mix ture
was stirred for 12 h un til brown ish pre cip i tates formed. The
prod uct was poured into meth a nol (50 mL), while white pre-
cipitates appeared. The solids were fil tered and dried in
vacuo to give 5b (320 mg) in 64% yield. It was spar ingly sol-
u ble in CH3OH and DMF, but in sol u ble in most or ganic sol-
vents. IR (Kr) 3318 (s, -OH), 2946, 2864, 1651, 1626, 1603,
1487, 1456 cm-1. 1H NMR (300 MHz, DMF) 1.59 (br, 2H,
-CH2-), 4.47 (br, 2H), 5.43 (br, 2H, =CH-), 6.56 (br, 2H, Ph).
Polymerizationof p-diacetyloxybenzonorbornadiene 1a
To a Schlenk flask (10 mL) con tain ing MoCl5 (50 mg)
underanitrogenatmospherewasaddedchlorobenzene(2.0
mL),followedbySnMe4 (0.070 mL). The mix ture was stirred
with a mag netic bar at room tem per a ture, while the color
turned from brown to red dish-brown. Af ter 10 min, 1a (400
mg) was in jected into this mix ture through a sy ringe. The vis-
cos ity of so lu tion in creased while the poly mer iza tion pro-
ceeded. It was di luted first by the ad di tion of CHCl3 (20 mL),
then was poured into a large ex cess of meth a nol. The white
pre cip i tates were fil tered and dried in vacuo to give 5a (384
mg)in96%yield. ItwassolubleinCHCl3, THF, DMF and ac-
etone,slightlysolubleinbenzeneandethylacetate,butinsol-
1
13C NMR (100 MHz, H decoupled, DMF) 42.7, 71.8,
117.4, 133.5 and 148.5.
Polymer of Benzonorbornadiene (5c)
1H NMR (300 MHz, CDCl3) 1.72 & 2.64 (br, 2H to tal,
-CH2- for trans and cis iso mers in ca. 1:1 ra tio), 3.79 & 4.17
(br, 2H to tal, -CH-), 5.63 & 5.71 (br, 2H to tal, =CH-), 7.24
1
(br, 4H). 13C NMR (75 MHz, Hdecoupled,CDCl3) 42.72,
46.84, 123.93, 126.82, 133.40, 145.99.
Polymer of o-diacetyloxybenzonorbornadiene (6a)
1H NMR (300 MHz, CDCl3) 1.79 & 2.59 (br, 2H to tal,
-CH2- for transand cis isomersinca. 1:1ratio), 2.26(br, 6H),
2.83 & 4.20 (br, 2H to tal, -CH-), 5.68 (br, 2H), 7.05 (br, 2H).
Ox i da tion of poly mer 5b to 7
Polymer 5b was dis solved in d8-dioxane, and to it was
added DDQ (1.2 eq) un der a ni tro gen at mo sphere. The so lu-
tion was stirred for 2 h at room tem per a ture, while the color
changed to dark blue-violet. The NMR spec trum was taken
withoutpurification.Thenitwaspouredintomethanolwhile
pur plish black pre cip i tates formed. It was fil tered, and the
flitrate was washed with meth a nol to yield poly mer 7. IR
Fig. 3. 1H NMR spec tra of ran dom poly mer8 with var-
i ous m:n ra tios: (a) poly mer with m = 0 (iden ti-
cal to 5c), (b) co pol y mer with m:n = 1:5.5, (c)
copolymerwithm:n=3:1, and(d)polymerwith
n = 0 (iden ti cal to5a).