Chiral gold–PPA nanocomposites with tunable helical sense and morphology

Abstract

A novel type of stimuli-responsive dynamic helical polymer–metal nanoparticle nanocomposite formed by a helical poly(phenylacetylene) (PPA) combined with gold nanoparticles (AuNPs) is described.

From Sergeants and Soldiers to Chiral Conflict Effects in Helical Polymers by Acting on the Conformational Composition of the Comonomers

“… [55, 56] From the mechanistic point of view, in chloroform this process is originated by the ap conformation of the sergeant ( S )‐ 2 (Figure 5 b), [48] which commands the soldier ( S )‐ 1 to adopt an ap conformation that in turn induces the same P helix orientation in the copolymer chain. The conformational composition at the pendants was determined by fixing their ap or sp conformations by addition of either monovalent or divalent metal ions (see the Supporting Information) [46–48] …”

From Sergeants and Soldiers to Chiral Conflict Effects in Helical Polymers by Acting on the Conformational Composition of the Comonomers

“…To perform these studies,the 4-ethynylanilides of (R)-or (S)-a-methoxy-a-phenylacetic acid (MPA) were chosen as chiral soldiers (monomers (R)-or (S)-1;F igure 3), [42][43][44][45][46][47] while the 4-ethynylanilide of the (S)-mandelic acid (MA) was selected as chiral sergeant (monomer (S)-2). [48] Thedifference between these two monomers is one substituent at the chiral carbon.…”

“…Thec onformational composition at the pendants was determined by fixing their ap or sp conformations by addition of either monovalent or divalent metal ions (see the Supporting Information). [46][47][48] In THF,h omopolymers poly-(S)-1 and poly-(S)-2 show CD traces indicative of as crew sense excess towards the P helices (CD 380 (+ +); Figure 5a), [56][57][58] although their magnitude is moderate.T his fact indicates as light screw sense excess towards a P helix in both polymers.C Ds tudies for the poly-[(S)-1 r -co-(S)-2 (1Àr) ]copolymer series in this solvent show that all the copolymers adopt ap referred P helix, although the magnitude of the CD spectra is approximately twice that of the original homopolymers (Figure 5c). This chiral enhancement effect is observed in all the poly-[(S)-1 r -co-(S)-2 (1Àr) copolymer series,i ndependently of the copolymer composition, which indicates that an effective chiral communication mechanism is being produced within the copolymer chain.…”

Chiral transfer‐dictated self‐assembly of chiral block copolymers

“…[56,[188][189][190][191][192][193][194][195][196][197][198] Moreover, the co-assembly of BCPs* and inorganic nanoparticles realized chiral spatial arrangement of nanoparticles (Figure 9B). [88,[199][200][201][202][203][204] A fine-tuning of the dimension and loading of nanoparticles were required to accommodate the nanoparticles inside BCPs* assemblies commensurately. [202][203][204] As an alternative to these two approaches, it is feasible to implement the co-assembly of BCPs* and precursors into designed assemblies (Figure 9C), then in situ generated chiral inorganic materials, for example, Ni and Ti networks.…”