Synthesis and Polymerization of an <i>ortho</i>-<i>para</i>-Substituted Tetraalkoxy [2.2]Paracyclophane-1,9-diene.

This contribution describes the synthesis of an unsymmetrical substituted tetraalkoxy[2.2]paracyclophane-1,9-diene comprised of an <i>ortho</i>-substituted and a <i>para</i>-substituted dioctyloxybenzene. (<i>S</i>_p)-4,5,12,15-tetraoctyloxy-[2.2]paracyclophane-1,9-diene ((<i>S</i>_p)-pCpd) and (<i>R</i>_p)-4,5,13,16-tetraoctyloxy-[2.2]paracyclophane-1,9-diene ((<i>R</i>_p)-pCpd) are formed as planar chiral enantiomers. Unlike other tetraalkoxy-substituted pCpds that form as diastereomers, both the (<i>S</i>_p)-pCpd and the (<i>R</i>_p)-pCpd can be polymerized via ring-opening metathesis polymerization (ROMP) using Grubbs' third generation initiator (G3) as it is achiral. Living ROMP afford copolymers featuring alternating <i>cis</i>,<i>trans</i>-poly(<i>p</i>-phenylenevinylene)s (PPV)s. The polymers' unique, blue-shifted optical properties are due to the alkoxy-substitution in the polymer's backbone and the resulting materials could be photoisomerized to the all-<i>trans</i> polymer. This strategy affords tetraalkoxy-pCpd monomers in high yields for the polymerization of soluble PPVs with low or narrow dispersities.