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

Abstract

This contribution describes the synthesis of an unsymmetrical substituted tetraalkoxy[2.2]paracyclophane-1,9-diene comprised of an ortho-substituted and a para-substituted dioctyloxybenzene. (Sp)-4,5,12,15-tetraoctyloxy-[2.2]paracyclophane-1,9-diene ((Sp)-pCpd) and (Rp)-4,5,13,16-tetraoctyloxy-[2.2]paracyclophane-1,9-diene ((Rp)-pCpd) are formed as planar chiral enantiomers. Unlike other tetraalkoxy-substituted pCpds that form as diastereomers, both the (Sp)-pCpd and the (Rp)-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 cis,trans-poly(p-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-trans polymer. This strategy affords tetraalkoxy-pCpd monomers in high yields for the polymerization of soluble PPVs with low or narrow dispersities.