No abstract

A new pyridine-terminated fluorophore of (E)-4-(2-(anthracen-9-yl)vinyl)pyridine (AnPy) with intramolecular charge transfer and aggregation-induced emission properties was synthesized and was blended with polytyrosine (PTyr) through hydrogen-bond interactions.

Tetraphenylthiophene (TP) with aggregation-enhanced emission (AEE) property was used as terminal fluorophore of the water-soluble poly(γ-propargyl-l-glutamate) (PPLG)-based polymers of TP-iPPLGs to probe the relationship between the secondary structure (α-helix) of polypeptides and the AEE-related emission behavior. Intermolecular aggregation of the terminal TP unit in TP-iPPLG is sterically blocked by the large α-helical PPLG chains, leading to the weak AEE-related fluorescence in water. In contrast, the intermolecular approach between the terminal TP units of TP-iPPLG is accessible if TP was connected by peptide chin in random coil structure. Therefore, the helix-to-coil transition induced in the alkaline aqueous solution successfully enhances the emission intensity of the TP-iPPLG solution. The pH-induced conformation change in relationship to the AEE-related emission behavior is therefore evaluated in this study.

An organic azine derivative of CN4OH, containing both para- and ortho-hydroxyl (o- and p-OH) groups, is a fluorescent material with an emission efficiency dependent on the degree of crystallinity.

ARTICLE RSC Adv.As restricted intramolecular rotation (RIR) is the main mechanism responsible for the aggregationinduced or -enhanced emission (AIE or AEE), we thereby use rigid polyrotaxane to impose effective RIR for an ionic water-soluble, AEE-active luminogen of sodium 4,4',4'',4'''-(thiophene-2,3,4,5tetrayl)tetrabenzenesulfonate (TPS). Jeffamine-included β-cyclodextrin (JA-included β-CD) with cationic ammonium terminals was used as rigid component to complex with sulfonate anions of TPS, resulting in iTP-CD-JA complex for characterization. Comparison is also made on complex of iTP-JA prepared from the complexation of TPS with the flexible JA chains. Without the incorporation of rigid β-CD rings, the iTP-JA complex is inferior to the iTP-CD-JA complex in the emission efficiency. The role of rigid template in imposing effective RIR on AEE-active luminogen is thus demonstrated in this study.ARTICLE 2 | RSC Adv., 2014 RSC Adv.