1:30pm - 1:45pmOral
Highly Efficient Luminescent Polymers Synthesized through the McMurry Coupling Reaction
Wuhan University, China
A series of linear polymer through the McMurry-coupling reaction from 9-phenyl-carbazole substituted bis-benzoyl derivatives, with some advantages including the simple synthesis, high yield and easy purification. Thanks to the formed oligo-tetraphenylethene (TPE) structure during the polymerization process, the polymers possessed the typical characteristic of aggregation induced emission (AIE), and good solubility in common organic solvents like THF, DCM, and chloroform, coupled with high thermal stability with the Td95% values higher than 400 oC. More importantly, the emission color could be conveniently tuned from ultraviolet to sky blue, green and yellow, with the maximum photo efficiency up to 30%, by simply changing substituted groups.
1:45pm - 2:00pmOral
Construction of Tunable Fluorescence AIE@dot with Regulating the AIE and TICT Effect and Their Biological Imaging Applications
National Chung Hsing University, Taiwan
3, 6- divinylaryl substituted carbazole with the aggregation-induced emission enhancement (AIE) activity are prepared. At first, this low luminance molecule can present AIE and form fluorescent organic nanoparticles (FONs) in ethanol, which was constructed and collected as bright AIE@dots by use of the Stöber method silica coating. Alternatively, the multicolor AIE@dots can also be achieved by doping with variable ratios of octadecyltrimethoxysilane (ODS), which can regulate the AIE and TICT environment of compound inner the nanoparticle, before surface silanization. The AIE@dots were further modified with hydrophilic APS bilayers and yielded functionalized AIE@dots nanocomposites with tunable fluorescence from green to organ-red. Systematic investigations verify that the resulting AIE@OH could display extremely high stability in aqueous media and the as-prepared AIE@dots for cell imaging was preliminarily performed.
2:00pm - 2:15pmOral
Iptycene Derivatives with Aggregation-induced Emission Characteristics and Room Temperature Phosphorescence
South China University of Technology, China
Recently, pure organic room temperature phosphorescence (RTP) has attracted much attention from scientists all over the world because of their great potential in high-tech applications such as electroluminescent devices, time-resolved biological imaging, cellular hypoxia imaging, temperature monitoring, chemo-sensing, and security markings. However, there are quite limited examples of pure organic RTP materials reported so far.
In this work, a series of iptycene derivatives were designed and synthesized with both vibratile and rotatable aromatic rings. Based on the restriction of intramolecular motion mechanism, typical aggregation-induced emission behaviour was observed from these iptycene derivatives. Fluorescence enhancement was observed from their THF solutions to their aqueous mixtures with 99 vol% water content. Most importantly, their crystalline states exhibit both fluorescence and phosphorescence emission at room temperature. The phosphorescence emission maxima of the crystals generally red-shifted 120-150 nm compared with the corresponding fluorescence emission maxima and the phosphorescence lifetimes are up to 4.4 ms. These findings suggested that the iptycene derivatives are promising AIE compounds with RTP characteristics.
2:15pm - 2:45pmInvited
Stimuli-responsive Small Organic Molecules With Aggregation Induced Emission
Tsinghua University, China
Development of stimuli-responsive molecules and materials is attractive due to their potential and important applications in fields of sensors, drug delivery, optical data storage, security inks and optoelectronic devices. Among them, photo- and mechano-responsive molecules with aggregation induced emission property are particularly appealing due to their excellence selective activation with spatial and temporal control and their bright emission in aggregate and solid state. Herein, several activatable benzophenone derivatives by scratching and trityl dyes by light irradiation are reported exhibiting aggregation induced emission under photo- and mechano stimuli. Halides of 2-aminophenyl ketone exhibited well on-off luminescence property under scratching-fuming process. When non-fluorescent ethanol solution of 2’,5-dichloro substituted 2-aminophenyl ketone was smeared on a glass surface, the glass surface showed no emission after drying. However, after being scratched with a pipette tip, distinct cyan emission immerged on the glass surface. Subsequently, upon being fumed with ethanol vapor and scratched one more time, the glass surface again showed the process of non-emission to cyan emission under 365 nm UV irradiation. The mechanism of this mechanofluorochromic property was expected as the molecular packing transition from the amorphous to crystalline state. On the other hand, when triphenylmethanol solution was irradiated for a period of time using a strong power 254 nm UV lamp, the solution changed from transparent to pale yellow, meanwhile exhibited strong violet activated fluorescence (Ex = 320 nm, Em = 380 nm). As for solid triphenylmethanol, increasing the exposure time can exhibit the same properties as the solution state. Under TEM we observed a large number of small particles of nanometer size, we speculated that UV irradiation caused the aggregation of triphenylmethanol molecules, forming aggregates phosphor nanoparticles.
2:45pm - 3:00pmOral
The Design of Sensing Systems Based on Aggregation Induced Emission
Wuhan University, China
In recent years, we have demonstrated a series of sensors based on aggregation-induced emission (AIE) effect.
- With the aid of graphene oxide (GO), the sensitivity and selectivity of AIE-based biosensors could be improved. We reported that a complex of GO and AIE dyes response to particular biomacromolecules by choosing different AIE dyes. For example, the derivative of hexaphenylsilole functionalized by two amino groups and GO give an “off-on” response to DNA selectively, while a complex of another AIE dyes and GO could detect the presence of bovine serum albumin nearly without the influence of other proteins.
- We designed a new Hg2+ chemodosimeter containing tetraphenylethylene (TPE) and nitrobenzene groups, by coupling Hg2+ promoted deprotection reaction with ketone-enol isomerization, which realized the multistage amplifying effect. In the presence of Hg2+, both of color and fluorescence changed. When fabricated as test strips, immediate color change from colorless to purple could be visually observed by naked-eyes without the aid of any additional equipment, which was indeed reliable for the convenient and rapid on-site detections.
3:00pm - 3:15pmOral
Selective Host-Guest Cocrystallization of Pyridine-Functionalized Tetraphenylethylene with Phthalic Acids
the Hong Kong University of Science and Technology, Hong Kong S.A.R. (China)
Tetraphenylethylene (TPE) and its derivatives are the most typical and most widely studied organic compounds with aggregation-induced emission (AIE) characteristics. Due to their propeller-like structures, V-like clefts exist between the aryl rings, making them promising as host compounds. However, such possibility is seldom explored. Here, we reported for the first time that TPE derivatives (TPE-Pys) bearing two or four pyridine rings at the para-position of the phenyl rings could selectively include triangular(Δ-like) m-phthalic acid from a mixture of o-, m- and p-phthalic acids due to their shape complementary. Host-guest cocrystals were obtained that showed redder emission than TPE-Pys. The emission of the cocrystal 1–5 could be reversibly switched between yellow and red colors by alternately exposure to HCl and ammonia vapor. The host-guest cocrystals not only exhibited a great potential for selectively recognizing and separating m-phthalic acid and as multicolor emission materials, but also demonstrated a capability to use as secret ink for their reversible color change by varying the host-guest interactions.
3:15pm - 3:30pmOral
The Aggregation-induced Emission Behavior of Pyrrolopyrrole-based Derivatives as a Novel Class of AIEgen
Beijing Institute of Technology, China
The AIE-active molecules with wide applications ranging from chemosensing, bioimaging, optoelectronics to stimuli-responsive systems have been extensively designed and synthesized in last decades. Therefore, we developed a novel AIEgen of pyrrolopyrrole-based derivatives and studied their properties and applications.
Two pyrrolopyrrole-based derivatives 1,2,4,5-tetraphenyl-1,4- dihydropyrrolo[3,2-b]pyrrole (DPPTP) and 4', 4''-(2,5-diphenyl-pyrrolo[3,2-b]pyrrole-1,4-diyl)bis([1,1'-biphenyl]-4-carbonitrile) (DPPDC) were synthesized via one-pot and two steps methods, respectively. DPPTP featured AEE and CEE properties , and DPPDC, increasing phenyl group as a rotator and incorporating cyan as an electron withdrawing group, also featured AEE properties with 11-fold enhancements which was significantly superior to that of DPPTP with 1.3-fold enhancements. Pyrrolopyrrole core can be used as responsive site for detecting acid because that was predicted to be the most efficient electron-donor among the 10 π-electron systems . We investigated that the solid films prepared by spin-coating a DPPTP solution in THF onto a quartz glass showed rapid response and excellent selectivity to chloroform. Experimental results showed that hydrochloric acid produced from the photodecomposition of chloroform was the main reason for the fluorescent response of the DPPTP film to chloroform. At the same time, trifluoroacetic acid (TFA) could make the emitting color change from yellow to orange-red with as-prepared paper containing DPPDC due to the acid-base interaction.
Additionally, it was found that four different kinds of crystal structures of DPPDC was cultivated from different solvents systems via solvent slow diffusion method. Four crystals respectively emitted purple, blue, green and turquoise at 467, 483, 496 and 493 nm, which manifested the polymorphism-dependent fluorescent emission property. Pyrrolopyrrole-based derivatives can act as novel AIEgens for practical applications.