Synthesis of Optically Active Conjugated Polymers
Bearing <i>m</i>‑Terphenylene Moieties by Acetylenic
Coupling Polymerization: Chiral Aggregation and Optical Properties
of the Product Polymers
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Abstract
The acetylenic coupling polymerization
of d-hydroxyphenylglycine-derived <i>m</i>-terphenylene
diynes <b>1</b>–<b>5</b> using Pd/Cu catalyst gave
the corresponding polymers [poly(<b>1</b>)–poly(<b>5</b>)] with <i>M</i><sub>n</sub> = 12 000–60 000
in 53–89% yields.
The polymers were soluble in THF and DMF. CD and UV–vis spectroscopic
analysis revealed that <i>p,p</i>′-phenyleneethynylene-linked
poly(<b>1</b>), poly(<b>3</b>), and poly(<b>5</b>) formed chiral higher-order structures in THF/H<sub>2</sub>O mixtures,
while <i>m,m</i>′-phenyleneethynylene-linked poly(<b>2</b>) and poly(<b>4</b>) did not. The sign of CD signal
of poly(<b>1</b>) was reasonably predicted by time-dependent
density functional calculations of the model system. The polymers
emitted fluorescence with quantum yields ranging from 0.2–14.8%
