Phenyleneethynylene Macrocycle‐Fused Phenylacetylene Monomers: Synthesis and Polymerization

Abstract

Phenyleneethynylene macrocycle‐substituted acetylenes were synthesized by repetition of the Sonogashira coupling reaction, and the elimination reaction of the terminal acetylene protecting group. The monomers were polymerized with a rhodium catalyst, [Rh(nbd)Cl]2, at the terminal acetylene unit, and the polymerization mixtures were purified by precipitating into methanol to yield the corresponding poly(phenylacetylene) derivatives as yellow‐red powders, which had a high degree of polymerization ($\overline {DP}$ ≈ 500) in spite of their steric bulkiness. The trimethylsilyl and pentamethyldisiloxanyl groups of polymers improved their solubility, and the polymers were soluble in common organic solvents, such as toluene, chloroform and tetrahydrofuran.magnified image

Push–Pull Macrocycles: Donor–Acceptor Compounds with Paired Linearly Conjugated or Cross-Conjugated Pathways

“…The tert -butyl groups were incorporated into our design to promote solubility. Compounds based on the parent macrocyclic tetrabenzo[18]­cyclyne (TBC) core have been synthesized but have received little attention otherwise. − However, examples of related structures are well-known, including work by Tobe ,, and Haley on TBCs with intraannular alkynyl groups. The photophysical properties of some of these graphyne fragments have been studied, and as discussed above, this structure represents a useful platform for the control of two-dimensional self-assembly.…”

Acetylenic Polymers: Syntheses, Structures, and Functions

“…The prerequisite to realize this attractive potential is to establish versatile processes for synthesizing the polymers. This has motivated many research groups all over the world to work on the exploration of acetylene-based polymerization reactions. − As a result, a large variety of acetylenic polymerization reactions have been developed, especially after the ground-breaking work of Shirakawa, MacDiarmid, and Heeger in the 1970s …”

Polar tagging in the synthesis of monodisperse oligo(p-phenyleneethynylene)s and an update on the synthesis of oligoPPEs

“…If the latter is true, then the use of 1-hydroxyethyl (HOE) or HOP instead of HOM as polar protecting groups for alkynes could prevent carbometalation. Although HOP is a sterically more demanding group, we decided in favor of HOE because the removal of HOP requires refluxing in toluene for several hours in the presence of sodium hydride or potassium hydroxide [ 34 , 36 – 38 42 , 50 – 52 76 ] whereas we expected that HOE could be detached through treatment with γ-MnO 2 and powdered KOH in diethyl ether at room temperature, i.e. under the same, comparatively mild reaction conditions that had been used for HOM protected alkynes.…”

“…This is of no concern provided the alkyne dimer and the alkynyl–aryl coupling product can be easily separated, and this is what the HOM and related HOP group guarantee since they act as polar tags for the chromatographic separation. Polar tagging with HOM [47–49] or HOP [34,42,45,50–57] has been the key to the successful syntheses of a variety of aryleneethynylene building blocks and oligomers [42,45,47–52] and of oligoeneynes [53] including the natural marine compound callyberyne [54]. …”