Herein, macromolecular gears composed of helical poly(phenylacetylenes) (PPAs) bearing short oligopeptides as pendant groups are described, in which the two structural motifs (framework and substituents) are combined. These gears are obtained by polymerization of the acetylene groups introduced at the C‐terminus of short oligopeptides formed by achiral (Aib)n units (n=1–3) derivatized at the N‐terminus by a single enantiomer (R or S) of α‐methoxy‐α‐trifluoromethylphenylacetic acid (MTPA, Mosher's reagent). The chiral information of the MTPA is transmitted to the achiral Aib fragments and, through either chiral tele‐induction and/or chiral harvesting mechanisms, is further transferred to the polyene backbones, which adopt preferentially P or M helical senses. Moreover, these materials also show dynamic behavior and respond to the action of external stimuli by either inverting the P/M sense and/or modifying the elongation in fully reversible processes.

Polyphenylacetylenes bearing primand secamine groups are barely known due to their poisoning activity towards the polymerization catalyst. Herein we prepare 11 different amino polymers in high yields by direct polymerization of their corresponding ammonium salts in water using [Rh(cod)2] + BF4as catalyst. They are stable, water soluble, and show a helical structure that responds to external stimuli (polarity, pH and metal ions) acting on the pendants. The location of the amino group in the pendant is shown to be critical for the helical response to protonation.

The dynamic behavior of helical polymers bearing pendant groups with two chiral centers was studied. Controlled conformational changes at the chiral units placed either closer to or further away from the main chain promote different helical structures. Although the first residue is usually responsible for determining a specific helicity (P or M), we now found that the second chiral center is also able to induce a preferred helical sense when it is located closer in space to the main chain, thereby cancelling the order from the first chiral moiety. This result was achieved through proper coordination with a metal cation. As proof of concept, poly(phenylacetylene)s (PPAs) that bear one and two chiral amino acid units of different sizes and configuration combinations (l/d‐alanine and l/d‐phenylalanine) as pendants were evaluated. In total, ten polymers were studied. This constitutes the first report of axial control from a remote stereocenter in polymers bearing complex chiral pendants.

No abstract

Smart stimuli-responsive fluorescent materials are of interest in the context of sensing and imaging applications. In this project, we elaborated multi-dynamic fluorescent materials made of a tetraphenylethene fluorophore displaying aggregation-induced emission and short cysteine-rich C-hydrazide peptides. Specifically, we show that a hierarchical dynamic covalent self-assembly process, combining disulphide and acyl-hydrazone bonds formation operating simultaneously in a one-pot reaction, yields cage compounds at low concentration (2 mM) while soluble fluorescent dynamic covalent networks and even chemically cross-linked fluorescent organogels are formed at higher concentrations. The number of cysteine residues in the peptide sequence impacts directly the mechanical properties of the resulting organogels, Young moduli varying 2500-fold across the series. Those materials underpinned by a nanofibrillar network display multi-dynamic responsiveness following concentration changes, chemical triggers, as well as light irradiation, all of which enable their controlled degradation with concomitant changes in spectroscopic outputs -self-assembly enhancing fluorescence emission by ca. 100-fold and disassembly quenching fluorescence emission.

Supramolecular polymers are self-assembled materials displaying adaptive and responsive “life-like” behaviour which are often made of aromatic compounds capable of engaging in π-π interactions to form larger assemblies. Major advances...

The dynamic behavior of helical polymers bearing pendant groups with two chiral centers was studied. Controlled conformational changes at the chiral units placed either closer to or further away from the main chain promote different helical structures. Although the first residue is usually responsible for determining a specific helicity (P or M), we now found that the second chiral center is also able to induce a preferred helical sense when it is located closer in space to the main chain, thereby cancelling the order from the first chiral moiety. This result was achieved through proper coordination with a metal cation. As proof of concept, poly(phenylacetylene)s (PPAs) that bear one and two chiral amino acid units of different sizes and configuration combinations (l/d‐alanine and l/d‐phenylalanine) as pendants were evaluated. In total, ten polymers were studied. This constitutes the first report of axial control from a remote stereocenter in polymers bearing complex chiral pendants.

Herein, macromolecular gears composed of helical poly(phenylacetylenes) (PPAs) bearing short oligopeptides as pendant groups are described, in which the two structural motifs (framework and substituents) are combined. These gears are obtained by polymerization of the acetylene groups introduced at the C‐terminus of short oligopeptides formed by achiral (Aib)n units (n=1–3) derivatized at the N‐terminus by a single enantiomer (R or S) of α‐methoxy‐α‐trifluoromethylphenylacetic acid (MTPA, Mosher's reagent). The chiral information of the MTPA is transmitted to the achiral Aib fragments and, through either chiral tele‐induction and/or chiral harvesting mechanisms, is further transferred to the polyene backbones, which adopt preferentially P or M helical senses. Moreover, these materials also show dynamic behavior and respond to the action of external stimuli by either inverting the P/M sense and/or modifying the elongation in fully reversible processes.