Supporting information
A Solution-Processible Poly (p-phenylene vinylene) without
Alkyl Substitution: Introducing the Cis Vinylene Segments
in Polymer Chain for Improved Solubility, Blue Emission
and High Efficiency
Fangfang Wang, Feng He, Zengqi Xie, Mao Li, Xin Gu, Muddasir Hanif, Bing Yang,
Houyu Zhang, Ping Lu, Yuguang Ma*
1.Measurement of the content of cis-vinylenes in 2,5-DP-PPV
The content of cis-CH=CH bond linkage was estimated by integrating these signals
in the 1HNMR spectrum of 2,5-DP-PPV (Fig.1-A) and using the formula below.
cis(%)  100
I cis  I cis  phenyl
I all
Where I is the sum of the integrations of the NMR signals. Icis is the integrations of
cis-vinylenes signals. Icis-phenyl is the integration of phenyl ring signals in the cis
isomer which is estimated from the integrations of cis-vinylenes signals. Iall is the
integrations of the all polymer singnals. The percentage cis- content of 2,5-DP-PPV is
about 50%.
Figure1. Comparison of 1H NMR spectra for 2,5-DP-PPV before (A) and after (B)
photo-irradiation, Signals a and b between 6.4 to 6.6 ppm respectively attributed to
the protons on cis-vinylenic HC=CH double bands. Signals c and d at about 7.1 ppm
and 7.3 ppm respectively appear for the protons on trans-vinylenic HC=CH double
bands.
We further proved cis-content of the polymer using IR spectrum (Fig.2). In the IR
spectrum of 2,5-DP-PPV, the typical absorption of the trans-vinylene C-H out of
plane vibration was at 968cm-1 and there was also a feature at 870cm-1 indicative of a
cis-vinylene unit. The relative heights of these two features can be compared to give a
quantitative analysis of the cis- and trans-content of the sample. The ratio of
absorption coefficients (cis/trans) for a similar system, DPO-PPV, was approximated
as 1.36 using NMR and IR analysis. The cis-contents of 2,5-DP-PPV was thus
calculated using the following equation1.
cis (%)  100
1.36 Acis
1.36 Acis  Atrans
where Acis and Atrans represent absorbencies of the 870cm-1 and 968cm-1 bands in
the IR spectrum of 2,5-DP-PPV respectively, Acis =0.00875, Atrans = 0.01139. The
cis-content of DP-PPV thus calculated to be 51%.
Figure2. The FTIR spectrum of 2,5-DP-PPV in a KBr pellet. The arrows mark the
absorption for vinylenic C-H out-of-plane deformation (trans- CH=CH at 968 cm-1
and cis- CH=CH at 870 cm-1)
2.Estimate of absorption coefficients(cis/trans) ratio
DPO-PPV
Figure 3 shows the 1HNMR spectrum of DPO-PPV. The presence of the doublet
signals at about 6.4 and 6.9 ppm (marked “a” and “b”in Figure 3) with a coupling
constant (J=12HZ) confirmed the cis stereochemistry of CH-CH in the polymer. The
content of cis-CH=CH bond linkage was estimated by integrating the proton
resonance signals of –OCH2 – unit in the alkoxy side chains, the resonance signal at
3.83ppm and 3.49ppm which were attributed to the –OCH2- unit in the alkoxy side
chains were related to cis- and trans- olefins , respectively. 2 The ratio of cis-vinylene
is 87%.
Figure 3. 1H NMR spectra of DPO-PPV. The starred signal at 7.25 ppm is attributed
to trace CHCl3.
In the IR spectrum of DPO-PPV (Fig.4), the typical absorption of the trans-vinylene
C-H out of plane vibration was at 970cm-1 and there was a feature at 873cm-1
indicative of a cis-vinylene unit. Acis and Atrans represent absorbencies of the 873cm-1
and 970cm-1 bands in the IR spectrum of DPO-PPV respectively, Acis =0.01206, Atrans
= 0.00245.
cis (87%)  100
tAcis
tAcis  Atrans
where t represent the ratio of absorption coefficients(cis/trans) for DPO-PPV. The
ratio of absorption coefficients (cis/trans)was thus calculated to be 1.36.
Figure4. The infrared spectrum of DPO-PPV in a KBr pellet. The arrows mark the
absorption for olefinic C-H out-of-plane deformation (trans- CH=CH at 970cm-1 and
cis CH=CH at 873cm-1)
1. Dalton, A. B.; Coleman, J. N.; Panhuis, M. in het; McCarthy, B.; Drury, A.; Blau,
W. J.; Paci, B.; Nunzi, J. M.; Byrne, H. J. Journal of Photochemistry and
Photobiology A:Chemistry 2001, 144, 31-41
2. Liao, L.; Pang, Y.; Ding, L.; Karasz, F. E. Macromolecules 2001, 34, 7300.