Synthesis and chiral recognition ability of helical polyacetylenes bearing helicene pendants

Abstract

International audienceNovel polyacetylenes bearing an optically active or racemic [6]helicene unit as the pendant groups directly bonded to the main-chain (poly-1s) were prepared by the polymerization of the corresponding acetylenes (1-rac, 1-P, and 1-M) with a rhodium catalyst. The optically active polyacetylenes (poly-1-P and poly-1-M) formed a preferred-handed helical conformation biased by the optically active helicene pendants, resulting in the induced circular dichroism (ICD) in their π-conjugated polymer backbone regions. The optically active helical polymers, when employed as an enantioselective adsorbent, showed a high chiral recognition ability towards racemates, such as the monomeric [6]helicene and 1,1’-binaphthyl analogues, and enantioselectively adsorbed one of the enantiomers

Helicene-Based Chiral Auxiliaries and Chirogenesis

“…Thus, using 2-acetylene- [6]helicene 165, Yashima et al prepared a series of polymeric helicene pendants, poly-1-166, via the rhodium-catalyzed polymerization reaction (Scheme 30) [87]. This polymerization reaction gave stereoregular (cis-transoidal) polyacetylenes bearing the corresponding helicene pendants 166 with (P)-and (M)-polymeric chains with average molecular weight M n = 2.6 × 10 3 .…”

Synthesis of Optically Active Poly(diphenylacetylene)s Using Polymer Reactions and an Evaluation of Their Chiral Recognition Abilities as Chiral Stationary Phases for HPLC

“…Optically active poly(phenylacetylene)s with a preferred-handed helicity have been prepared [16] and some of these systems have been reported to exhibit good chiral recognition abilities as CSPs for HPLC because of their preferred-handed helical conformation [17][18][19][20][21][22][23][24][25][26]. However, very few optically active poly(diphenylacetylene)s have been prepared to date, which has limited research towards evaluating the scope and efficiency of the chiral recognition abilities of these materials [27][28][29][30][31][32][33][34][35].…”

Chiral nanostructure in polymers under different deposition conditions observed using atomic force microscopy of monolayers: poly(phenylacetylene)s as a case study

“…This property makes these materials very interesting in fields such as sensing, [28][29] The elucidation of the secondary structure adopted by PPAs is complicated by the dynamic character of the helix of these polymers that presents variations both in sense and in chain elongation. In addition, the monolayer must be deposited on an appropriate substrate, because the interactions between the solid support and the polymer can affect, not only to the intermolecular assembly of the polymer chains, but also to its helical conformation.…”