5616 Roex et al.
Macromolecules, Vol. 36, No. 15, 2003
Syn th esis of Mod el Com p ou n d s. P r ep a r a tion of 1,4-
Bis(bu tylsu lfa n yl)ben zen e, 8. A mixture of n-butanethiol
(12 g, 0.14 mol) and NaOtBuO (13.1 g, 0.14 mol) was dissolved
in methanol/THF (1/3) and in one portion added to a stirred
solution of 6 g (0.034 mol) of dichloro-p-xylene in THF (30 mL).
The mixture was heated to reflux, and after 2 h the reaction
was finished. The mixture was cooled to room temperature.
The salts were filtered off and the liquid was concentrated in
vacuo. A 9.6 g sample of 1,4-bis(butylsulfanyl)benzene (0.03
mol, 98%) was obtained as a yellow oil. 1H NMR (300 MHz,
CDCl3), δ: 7.2 (s, 4H, Har); 3.6 (s, 4H, Ar-CH2-SR); 2.4 (t,
4H, Ar-CH2-S-CH2-(CH2)2CH3); 1.5 (m, 4H, -S-CH2-CH2-
CH2-CH3); 1.3 (m, 4H, -S-CH2-CH2-CH2-CH3); 0.9 (m, 6H;
2 × CH3). MS (EI, m/z, relative intensity (%)): 250.
An a lytica l Da ta . NMR Mea su r em en ts. 1H spectra of the
monomers and conjugated polymers were acquired in
a
dedicated 5 mm probe on a Varian Inova 400 MHz (9.4 T)
spectrometer in CDCl3 and C2D2Cl4 respectively. The 13C
spectra were obtained at 100 MHz with a dedicated carbon
10 mm probe at 40 °C. Typical acquisition parameters are as
follows: a spectral width of 21 344 Hz, a filter bandwidth equal
to the spectral width, a pulse width of 13 µs, an acquisition
time of 0.7 s, and a processing line broadening of 7.5 Hz. For
both monomers and polymers, a solution of 46.5 mg in 3.5 mL
of CDCl3, containing 30 mg (25 mM) of chromium(III) acety-
lacetonate to reduce the T1C decay times, was used. According
to this procedure, a pulse preparation delay of only 5 s needs
to be maintained between consecutive pulses in order to obtain
fully quantitative results. Inversed gated decoupling was used
to avoid unequal NOE’s. 1H and 13C chemical shifts were
referenced relative to tetramethylsilane. For proton NMR, both
standard 1D and 2D COSY spectra19 were performed. For
carbon NMR, fully quantitative 1D spectra, APT20 (attached
proton test) and DEPT21 (distortionless enhancement by
polarization transfer) spectra were used. Carbon-proton 2D-
heteronuclear correlation spectra, HETCOR,22 were recorded
using an evolution time corresponding to an average direct
P r ep a r a tion of 1,4-Bis(bu tylsu lfin yl)ben zen e, 9. An
aqueous (35 wt %) solution of H2O2 (8.5 g, 0.085 mol) was
added dropwise to a solution of 0.4 g 1,4-bis(butylsulfanyl)-
benzene, TeO2 (1.3 g; 8 mmol), and three drops of concentrated
HCl in 128 mL of 1,4-dioxane. The reaction was followed on
TLC (19/1 dichloromethane/methanol), and as soon as the
overoxidation took place, the reaction was quenched by a
saturated aqueous NaCl solution (150 mL). The reaction
mixture was extracted with CHCl3 (3 × 200 mL), the combined
organic layers were dried over MgSO4 and concentrated in
vacuo. The reaction mixture was purified by column chroma-
tography (SiO2, eluent dichloromethane/methanol 19/1) to give
pure 1,4-bis(butylsulfinyl)benzene (6.3 g, 0.02 mol, 60%) which
1
coupling J CH value of 140 Hz.
Oth er Mea su r em en ts. Molecular weights and molecular
weight distributions were determined relative to polystyrene
standards with a narrow polydispersity (Polymer Labs) by size
exclusion chromatography (SEC). Separation to hydrodynamic
volume was obtained using light-scattering experiments on a
Spectra Series P100 (Spectra Physics) equipped with two
mixed-B columns (10 µm, 2 × 30 cm × 7.5 mm, Polymer Labs)
and a refractive index detector (Shodex) at 40 °C. SEC samples
were filtered through a 45 µm filter. HPLC grade THF (p.a.)
was used as the eluent at a constant flow of 1.0 mL/min.
Toluene is used as flow rate marker. Only for product 11 did
a different GPC column (5 µm, 100 Å, 300 × 7.5 mm) have to
be used.
1
appears as white crystals after evaporation of the solvent. H
NMR (300 MHz, CDCl3), δ: 7.3 (s, 4H, Har); 3.9 (s, 4H, Ar-
CH2-SR); 2.5 (t, 4H, Ar-CH2-S-CH2-(CH2)2CH3); 1.7 (m,
4H, -S-CH2-CH2-CH2-CH3); 1.4 (m, 4H, -S-CH2-CH2-
CH2-CH3); 0.9 (m, 6H; 2 × CH3). 13C NMR (100 MHz, CDCl3),
δ: 13.5 (2C); 21.9(2C); 24.6 (2C); 49.7 (1C); 57.6 (1C); 130.5
(1C); 137.8 (1C); 128.7 (2C); 129.0 (2C). MS (EI, m/z, relative
intensity (%)): 282. Tm ) 192 °C.
P r ep a r a t ion of 1,4-Bis(b u t ylsu lfin yl)-4′-ch lor ob en -
zen e, 10. A 1.3 g sample of N-chlorosuccinimide (0.01 mol)
was added portionwise as a solid to a solution of 3 g of 1,4-
bis(butylsulfinyl)benzene (0.01 mol) in 50 mL of dichoromethane
(time: 30 min). The solution was stirred at room temperature.
The mixture was extracted with water (3 × 50 mL) and dried
over MgSO4. After column chromatography (SiO2, chloroform/
methanol 19/1) the product could be isolated as white crystals
(2.7 g, 7.75 mmol, 78%). 1H NMR (300 MHz, CDCl3), δ: 7.5
(m, 2H, Har); 7.4 (m, 2H, Har); 5.54 (d, 1H, CHClS(O)R); 4.0
(s,2H, CH2S(O)R); 2.6 (m, 2H, S(O)CH2(CH2)2CH3); 2.4 (m, 2H,
S(O)CH2(CH2)2CH3); 1.7 (m, 2H, S(O)CH2CH2CH2CH3), 1.4 (m,
2H, S(O)CH2-CH2CH2CH3); 0.9 (m, 6H, 2 × CH3). 13C NMR
(100 MHz, CDCl3), δ: 13.5 (2C); 21.9 (2C); 24.6 (2C); 49.7 (1C);
51.1 (1C); 57.6 (1C); 74.7-73.1 (1C); 130.5 (1C); 137.8 (1C);
128.6 (2C); 129.0 (2C). MS (CI, m/z, relative intensity (%)): 349
[M + 1]+. Tm ) 143 °C.
P r ep a r a tion of P oly(p-P h en ylen e-1,2-bis(bu tylsu lfi-
n yl)eth ylen e) Accor d in g to th e Su lp h in yl Rou te, 11. A
solution of 0.4 g of monomer 10 (1.15 mmol) in THF (9 mL)
and a solution of NaOtBu (0.14 g, 1.5 mmol) in THF (5 mL)
were degassed for 1 h at 40 °C by passing through a continuous
stream of nitrogen. The base solution was added in one portion
to the stirred monomer solution. After 1 h, the reaction mixture
was poured dropwise in a well-stirred amount of ice-water
(150 mL). The mixture was neutralized with aqueous hy-
drdogen chloride and extracted with CHCl3 (3 × 50 mL). The
combined organic layers were concentrated in vacuo. The
obtained polymer was purified by precipitating it in an ice-
cold mixture of hexane/diethyl ether 1/1. A 0.15 g of yellow,
viscous polymer (0.48 mmol, 40%) was isolated and dried under
reduced pressure at ambient temperature.
1H NMR (300 MHz, CDCl3), δ: 7.5-7.1 (br m, 4H, Har); 3.9/
3.7 (br m, 2H, Ar-CHS(O)R-CHS(O)R-Ar); 2.7/2.5 (br m, 4H,
S(O)CH2(CH2)2CH3); 1.7 (br m, 4H, S(O)CH2CH2CHCH3); 1.4
(br m, 4H, S(O)CH2CH2CH2CH3); 0.9/0.8 (b, 6H, CH3). 13C
NMR (400 MHz, acetone-d), δ: 14.1 (2C, C10); 22.6 (2C, C9);
25.2 (2C, C8); 50.9/51.5 (2C, C5+6); 51.9 (2C, C7); 58.3 (C11);
130-138 (6C, C1-4). Mw ) 1592; polydispersity ) 1.5.
Direct insertion probe mass spectroscopy (DIP-MS) analy-
ses were carried out on a Finnigan TSQ 70. Either chemical
ionization with isobutane as reagent gas, mass range 90-600,
and heated at 120 °C/min from 30 to 650 °C or electron impact
mode, mass range 35-350, and an inter scan time of 2 s was
applied. The electron energy was 70 eV.
Resu lts a n d Discu ssion
(a ) Op tim a liza tion of th e NMR P r otocol. To
obtain the nature and amount of structural defects from
a
13C NMR spectrum, fully quantitative NMR spectra
are a prerequisite. In this way, our approach is different
from the one of Becker et al.,13 since they estimated the
amount of defects from the less chemical shift selective
1H NMR spectra. Another drawback of 1H NMR is that
several functionalities, e.g., internal triple bonds and
carbonyl groups, are not observed and their quantifica-
tion is not possible. To acquire quantitative 13C spectra,
a preparation delay of five times the longest T1 relax-
ation decay time has to be maintained between consecu-
tive pulses in order to let the magnetization return to
equilibrium. Therefore, the T1 decay times of all carbon
resonances were determined by means of the inversion
recovery technique (Table 1). Since the longest T1 decay
times are on the order of 2.7 s, a preparation delay of
at least 13.5 s is required (total experiment time of 21
h for 4300 repetitions). The influence of the paramag-
netic relaxation agent chromium(III) acetylacetonate on
the T1 relaxation decay times was examined. The
addition of chromium(III) acetylacetonate however has
to be made cautiously since too high concentrations can
reduce the T2 decay time significantly (increased line
width). Therefore, the effect of varying concentrations
of chromium(III) acetylacetonate on the T1 relaxation