Mann A, Weck M. Synthesis and Polymerization of an
ortho-
para-Substituted Tetraalkoxy [2.2]Paracylophane-1,9-diene.
ACS Macro Lett 2022;
11:1055-1059. [PMID:
35960910 DOI:
10.1021/acsmacrolett.2c00398]
[Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This contribution describes the synthesis of an unsymmetrical substituted tetraalkoxy[2.2]paracylophane-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.
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