Synthesis and Structures of the Di-LCPAs
We have synthesized various di-LCPA derivatives, including two groups with structural
variations on the alkyl side chain, the LC mesogen core, and the terminal groups
(Scheme 5). The Group 1 and Group 2 di-LCPAs have side chain type liquid crystallinity, where the LC mesogens are located on their side chains. The Group 1 di-LCPAs
have the terphenyl LC mesogen core directly attached to the polyene main chain, while
the Group 2 di-LCPAs have the LC groups attached via flexible spacers.
PA11 has an n-hexyl group and a para-terphenyl mesogen core linked with an
n-octadecyloxy moiety. PA12 has a phenyl group and a para-terphenyl mesogen core
linked with an n-pentyl moiety. The di-LCPAs with the second group have the mesogen
cores attached to the polyene main chain via flexible spacers. PA13 has a pentyl-PCH
group attached with an n-nonyloxy flexible spacer and an n-pentylphenyl group. PA14
has two phenyl groups directly attached to the polyene main chain with the second
phenyl having a PCH group attached via an n-dodecyloxy flexible spacer. PA15 has
a similar structure to PA14, with the phenyl group having a PCH moiety attached via a
n-dodecyloxy flexible spacer. On the other side of the PA15 main chain is a PCH group
with an n-nonyloxy flexible spacer. The synthesis of the monomers and polymers is
described in the report (San Jose et al. 2011).
The monomers of the di-LCPA derivatives were polymerized via a metathesis
reaction using tantalum (V) pentachloride (TaCl 5 ) as a catalyst and tetra-nbutyltin (n-Bu 4 Sn) as a co-catalyst. The polymerization reaction was conducted
at 80
C under an argon atmosphere using toluene as a solvent. The polymerization proceeded for 24 h followed by washing of the polymer in methanol (MeOH)
under constant stirring for 24 h. The precipitated polymers were then washed in
acetone for 24 h and dried under vacuum.
It has been extensively studied and reported by Masuda et al. that sterically
demanding monomers such as ortho-substituted phenyl acetylenes polymerize
Scheme 4 Structures of
PDPA derivatives showing
linearly polarized
luminescence
12 Liquid Crystalline Conjugated Polymers with Optoelectronic Functions
349
We have synthesized various di-LCPA derivatives, including two groups with structural
variations on the alkyl side chain, the LC mesogen core, and the terminal groups
(Scheme 5). The Group 1 and Group 2 di-LCPAs have side chain type liquid crystallinity, where the LC mesogens are located on their side chains. The Group 1 di-LCPAs
have the terphenyl LC mesogen core directly attached to the polyene main chain, while
the Group 2 di-LCPAs have the LC groups attached via flexible spacers.
PA11 has an n-hexyl group and a para-terphenyl mesogen core linked with an
n-octadecyloxy moiety. PA12 has a phenyl group and a para-terphenyl mesogen core
linked with an n-pentyl moiety. The di-LCPAs with the second group have the mesogen
cores attached to the polyene main chain via flexible spacers. PA13 has a pentyl-PCH
group attached with an n-nonyloxy flexible spacer and an n-pentylphenyl group. PA14
has two phenyl groups directly attached to the polyene main chain with the second
phenyl having a PCH group attached via an n-dodecyloxy flexible spacer. PA15 has
a similar structure to PA14, with the phenyl group having a PCH moiety attached via a
n-dodecyloxy flexible spacer. On the other side of the PA15 main chain is a PCH group
with an n-nonyloxy flexible spacer. The synthesis of the monomers and polymers is
described in the report (San Jose et al. 2011).
The monomers of the di-LCPA derivatives were polymerized via a metathesis
reaction using tantalum (V) pentachloride (TaCl 5 ) as a catalyst and tetra-nbutyltin (n-Bu 4 Sn) as a co-catalyst. The polymerization reaction was conducted
at 80
C under an argon atmosphere using toluene as a solvent. The polymerization proceeded for 24 h followed by washing of the polymer in methanol (MeOH)
under constant stirring for 24 h. The precipitated polymers were then washed in
acetone for 24 h and dried under vacuum.
It has been extensively studied and reported by Masuda et al. that sterically
demanding monomers such as ortho-substituted phenyl acetylenes polymerize
Scheme 4 Structures of
PDPA derivatives showing
linearly polarized
luminescence
12 Liquid Crystalline Conjugated Polymers with Optoelectronic Functions
349