Organic luminescent materials carrying no phenyl rings have attracted much interest from researchers due to their excellent biocompatibility and good biodegradability, which make them available for potential applications in a variety of biomedical areas, such as fluorescent bioprobe, drug delivery and gene carrier, and provide a new insight into the photophysical process of light emission. In this work, we studied the optical properties of poly[(maleic anhydride)-alt-(vinyl acetate)] (PMV), a pure oxygenic nonconjugated polymer and proved that the origin of its emission was associated with the clustering of the locked carbonyl groups. PMV exhibits solvatochromism: after interaction with electron-rich solvents, its absorption and emission shift to the longer wavelength region due to the formation of polymer/solvent complexes. This enables fine-tuning of its optical property by varying the solvent without the need of changing the chromophore.

A mitochondrion-specific AIEgen is a theranostic molecule, with the function of lighting up and killing cancer cells rather than normal cells.

Heterocyclic polymers have gained enormous attention for their unique functionalities and wide applications. In contrast with the well-studied polymer systems with five- or six-membered heterocycles, functional polymers with readily openable small-ring heterocycles have rarely been explored due to their large synthetic difficulty. Herein, a facile one-pot multicomponent polymerization to such polymers is developed. A series of functional polymers with multisubstituted and heteroatom-rich azetidine frameworks are efficiently generated at room temperature in high atom economy from handy monomers. The four-membered azetidine rings in the polymer skeletons can be easily transformed into amide and amidine moieties via a fast and efficient acid-mediated ring-opening reaction, producing brand-new polymeric materials with distinctive properties. All the as-prepared azetidine-containing polymers exhibit intrinsic visible luminescence in the solid state under long-wavelength UV irradiation even without conventionally conjugated structures. Such unconventional luminescence is attributed to the clusteroluminogens formed by through-space electronic interactions of heteroatoms and phenyl rings. All the obtained polymers show excellent optical transparency, high and tunable refractive indices, low optical dispersions and good photopatternability, which make them promising materials in various advanced electronic and optoelectronic devices. The ring-opened polymers can also function as a lysosome-specific fluorescent probe in biological imaging.

A luminogen with aggregation-induced emission characteristics is reported for bacterial imaging and antibiotics screening studies. The luminogen can light up bacteria in a wash-free manner, which simplifies the imaging process and increases its accuracy in bacterial detection. It can also be applied to high-throughput screening of antibiotics and fast evaluation of bacterial susceptibility, giving reliable results in less than 5 h.

TPE-Leu, an AIE luminogen, shows aggregation-induced chirality, and can self-assemble into helical micro/nanofibers, displaying good circularly polarized luminescence performance.

The development of efficient multicomponent tandem polymerization is attractive but challenging, owing to the limitations such as the required strict stoichiometric balance, the poor solubility and low molecular weight of the polymer products, etc. In this work, an efficient one-pot three-component polymerization of alkyne, carbonyl chloride and ethyl 2mercaptoacetate was reported. The polymerization of aromatic diyne (1), diaroyl chloride (2), and ethyl 2-mercaptoacetate (3) catalyzed by Pd(PPh 3 ) 2 Cl 2 /CuI proceeded smoothly under mild conditions at room temperature without strict stoichiometric balance of the monomers, affording poly(arylene thiophenylene) (P1) with high molecular weights (M w up to 156 000) in excellent yields (up to 97%). Single crystal structure of model compound 4 was obtained, aiding in verification of the complete transformation to the desired polymer product. The thiophene-containing conjugated polymer possesses good solubility in common organic solvents, good film-forming ability and high thermal stability. Meanwhile, the polymer shows typical aggregation-enhanced emission behavior: its solution is weakly emissive, but turns to be highly emissive when nanoaggregates or thin films are formed. Furthermore, thin film of P1 shows high refractive indices (n = 1.9461−1.6668) in a wide wavelength region of 400−1000 nm, which can be further modulated by UV irradiation. Well-resolved fluorescent photopattern can be generated by exposure of the thin film of P1 under UV irradiation through a copper photomask. The polymer also serves as an efficient fluorescent chemosensor for Ru 3+ with high sensitivity and selectivity, and the quenching constants for the sensing are up to 8.8 × 10 5 L mol −1 . This work provides a new polymerization concept and an efficient approach toward functional conjugated polymer materials, overcoming the limitations of multicomponent polymerization.

Fluorescent nanowires and thin films were fabricated by self-assembly of tetraphenylethene derivatives with aggregation-induced emission characteristics.

Multicomponent tandem reactions (MCTRs), with multiple bonds formed in a highly concise fashion in a single vessel, have been noted as one of the most powerful and popular synthetic strategies in modern organic chemistry. Attracted by their operational simplicity, synthetic efficiency, high atom economy, and environmental benefit, the MCTRs and the corresponding multicomponent tandem polymerizations (MCTPs) of alkynes, carbonyl chlorides, and aliphatic/aromatic thiols were developed. By combining the Sonogashira coupling reaction between alkynes and carbonyl chlorides, and the hydrothiolation reaction of electron-deficient alkynone intermediates, high atom economy was achieved in such one-pot, two-step, three-component reactions/polymerizations. The MCTPs can proceed efficiently under mild conditions near room temperature to afford sulfur-rich polymers with high molecular weight, high yield, high regioselectivity, and good stereoselectivity. Through the MCTPs of different combination of monofunctional and bifunctional monomers, polymers with tunable backbone structures and photophysical properties can be obtained. These polymers generally possess good solubility and film-forming ability. Their thin films enjoy high refractivity, and their photosensitivity enables easy modulation of the thin film refractive indices.