Disubstituted Polyacetylenes Containing Photopolymerizable Vinyl Groups and Polar Ester Functionality: Polymer Synthesis, Aggregation-Enhanced Emission, and Fluorescent Pattern Formation

Visible-Light-Driven α-Substituted Amines Enabled by In Situ Formation of Amine Substrate Aggregates

A visible-light-driven, photocatalyst-free, air-promoted, α-substituted reaction of amines with varying nucleophiles is described. The amine substrate aggregates formed in situ through physical π-π stacking by H2O regulation in organic solvent can absorb visible light and then generate iminium ion intermediates, which undergo nucleophilic substitution reactions with varying nucleophiles to afford α-substituted amines. This reaction features catalyst-free, good functional group tolerance, simple operation procedure, and green reaction conditions.

Facile Synthesis of Linear and Cyclic Poly(diphenylacetylene)s by Molybdenum and Tungsten Catalysis

Improved methods for the synthesis of linear and cyclic poly(diphenylacetylene)s by polymerization of the corresponding diphenylacetylenes using MoCl5 - and WCl4 -based catalytic systems have been developed. MoCl5 induces migratory insertion polymerization of diphenylacetylenes in the presence of arylation reagents such as Ph4 Sn and ArSnn Bu3 to produce cis-stereoregular linear poly(diphenylacetyelene)s with high molecular weights (number-average molar mass (Mn )=30,000-3,200,000) in good yields (up to 98 %). On the other hand, WCl4 induces ring expansion polymerization of diphenylacetylenes in the presence of Ph4 Sn or reducing reagents to produce cis-stereoregular cyclic poly(diphenylacetylene)s with high molecular weights (Mn =20,000-250,000) in moderate to good yields (up to 90 %). Both catalytic systems are applicable to the polymerization of various diphenylacetylenes having polar functional groups such as esters that are not efficiently polymerized by conventional methods using WCl6 -Ph4 Sn and TaCl5 -n Bu4 Sn systems.

Metathesis polymerization of monomers containing two diphenylacetylene units: synthesis and properties of poly(diphenylacetylene)s bearing diphenylacetylene units on the side chain

Selective metathesis polymerization provided highly emissive, gas-permeable, and thermally stable poly(diphenylacetylene)s possessing diphenylacetylene units on the side chain.

Mulifunctional Dendritic Emitter: Aggregation-Induced Emission Enhanced, Thermally Activated Delayed Fluorescent Material for Solution-Processed Multilayered Organic Light-Emitting Diodes

Thermally activated delayed fluorescence (TADF) materials emerged as promising light sources in third generation organic light-emitting diodes (OLED). Much effort has been invested for the development of small molecular TADF materials and vacuum process-based efficient TADF-OLEDs. In contrast, a limited number of solution processable high-molecular weight TADF materials toward low cost, large area, and scalable manufacturing of solution processed TADF-OLEDs have been reported so far. In this context, we report benzophenone-core carbazole dendrimers (GnB, n = generation) showing TADF and aggregation-induced emission enhancement (AIEE) properties along with alcohol resistance enabling further solution-based lamination of organic materials. The dendritic structure was found to play an important role for both TADF and AIEE activities in the neat films. By using these multifunctional dendritic emitters as non-doped emissive layers, OLED devices with fully solution processed organic multilayers were successfully fabricated and achieved maximum external quantum efficiency of 5.7%.

A novel post-polymerization modification route to functional poly(disubstituted acetylenes) through phenol–yne click reaction

This work not only enriches the precursor species for the synthesis of functional poly(disubstituted acetylenes) but also adds a powerful tool to the tool box for the preparation of other functional polymers through the post-polymerization modification route.

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

A series of optically active poly(diphenylacetylene) derivatives bearing a chiral substituent (poly-2S) or chiral and achiral substituents (poly-(2Sx-co-31-x)) on all of their pendant phenyl rings were synthesized by the reaction of poly(bis(4-carboxyphenyl)acetylene) with (S)-1-phenylethylamine ((S)-2) or benzylamine (3) in the presence of a condensing reagent. Their chiroptical properties and chiral recognition abilities as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) were investigated. Poly-2S and poly-(2Sx-co-31-x) (0.06 < x < 0.71) formed a preferred-handed helical conformation with opposite helical senses after thermal annealing despite possessing the same chiral pendant (h-poly-2S and h-poly-(2Sx-co-31-x)). Furthermore, h-poly-2S and h-poly-(2S0.36-co-30.64) emitted circularly polarized luminescence with opposite signs. h-Poly-2S showed higher chiral recognition abilities toward a larger number of racemates than poly-2S without a preferred-handed helicity and the previously reported preferred-handed poly(diphenylacetylene) derivative bearing the same chiral substituent on half of its pendant phenyl rings. h-Poly-(2S0.36-co-30.64) also exhibited good chiral recognition abilities toward several racemates, though the elution order of some enantiomers was reversed compared with h-poly-2S.

Highly emissive 'frozen-in' conjugated polymer nanofibers

Conjugated-polymer nanofibers with a thermodynamically stable, coarsened, disordered structure in an amorphous glassy state were fabricated via a freeze-drying method using a poly(diphenylacetylene) derivative. The nanofibers were extremely emissive, with a fluorescence (FL) quantum yield of approximately 0.34, which was much higher than that of both the cast film (0.02) and the solution (0.21). Similarly, the amplitude-weighted average FL lifetime of the nanofibers was 0.74 ns, which was much longer than that of the film (0.29 ns) and the solution (0.57 ns). This unusual and enhanced FL-emission behavior was attributed to the abruptly quenched chain structure that was created by the freeze-drying process. The polymer chains in the nanofibers remained frozen-in and the side phenyl rings were retained in a relaxed state. The metastable chains did not undergo vibrational relaxation and collisional quenching to generate the radiative emission decay effectively.

Different amine-functionalized poly(diphenylsubstituted acetylenes) from the same precursor

A facile and efficient synthetic route to different amine functionalized poly(diphenyl-substituted acetylenes) from the same precursor polymer is reported. The derived polymers demonstrated versatile applications.

Tweaking of the supramolecular gelation properties of a dipeptide based ambidextrous organogelator through the cooperative influence of hydrophobicity, steric bulk and conformational flexibility of the side chain residue of a single hydrophobic α-amino acid encrypted on a designed molecular frame

Fine tuning of gelation behavior via singular alteration of hydrophobic C_α-amino acid on the backbone of a dipeptide based ambidextrous organogelator.

Monosaccharide-functionalized poly(phenylacetylenes): in situ polymerization, hybridization with MWCNTs, and application in the reinforcement of chitosan rods

We report the fabrication of the hybrids of sugar-modified PPAs/MWCNTs, and the reinforcement of chitosan rods with the hybrids.

AIE macromolecules: syntheses, structures and functionalities

A comprehensive review of macromolecules with aggregation-induced emission attributes is presented, covering the frontiers of syntheses, structures, functionalities and applications.

Synthesis of Functional Disubstituted Polyacetylenes Bearing Highly Polar Functionalities via Activated Ester Strategy

We demonstrate a facile synthetic route to functional disubstituted polyacetylenes bearing highly polar groups based on polymer reactions. A pentafluorophenyl (PFP) ester-containing diphenylacetylene was designed and polymerized to obtain PFP activated ester-functionalized disubstituted polyacetylene (P1). P1 was used as a parent polymer to further react separately with diverse amines, giving rise to a series of functional disubstituted polyacetylenes with a chiral moiety and hydroxyl and carboxyl groups in high yields under mild condition. Spectral characterization data indicated that the polymers' structures were well consistent with the expected results. The helicity and emission property of polymers were also studied.