Jun Pang

Bio: Jun Pang is an academic researcher from Queen's University. The author has contributed to research in topics: Chemistry & Catalysis. The author has an hindex of 2, co-authored 2 publications receiving 367 citations.

A Blue Luminescent Star‐Shaped ZnII Complex that Can Detect Benzene

Abstract: Binding benzene: A novel blue luminescent star-shaped ZnII complex has been found to be able to detect benzene selectively by fluorescent quenching. This is attributed to the compoundapos;s high affinity to benzene, as demonstrated in the crystal structure (see picture; yellow: benzene, red: zinc).

Syntheses, structures, and electroluminescence of new blue luminescent star-shaped compounds based on 1,3,5-triazine and 1,3,5-trisubstituted benzene

Abstract: Four novel blue luminescent star-shaped compounds 1,3,5-tris(di-2-pyridylamino)benzene, 1, 1,3,5-tris[p-(di-2-pyridylamino)phenyl]benzene, 2, 2,4,6-tris(di-2-pyridylamino)-1,3,5-triazine, 3, and 2,4,6-tris[p-(di-2-pyridylamino)phenyl]-1,3,5-triazine, 4, have been synthesized and fully characterized. Compounds 1, 2 and 4 were prepared from the reactions of appropriate s-triazine and 1,3,5-trisubstituted benzene compounds with di-2-pyridylamine via copper-mediated Ullmann condensation in good yield (45–85%). Compounds 1, 2 and 4 show glass formation. Compounds 1–4 emit a blue color both in solution and in the solid state. The emission maxima of compounds 1–4 in the solid state are at λ = 412, 409, 393 and 440 nm, respectively. Fluorescence quantum yields of compounds 1–4 are 0.53, 0.16, 0.43 and 0.78, respectively. Electroluminescent devices using compounds 1–4 as the emitters were fabricated.

CO2-Switchable Single-Chain Polymeric Nanoparticles Enable Gas-Controllable Reaction Separation for Asymmetric Catalysis in Water

Abstract: Water-soluble single-chain polymeric nanoparticles (SCPNs), which isolated catalytic sites within a hydrophobic interior, made water-incompatible organometallic catalysis highly efficient in water. However, it is still a great challenge to conveniently control their hydrophilicity, so as to combine reactivity and recovery of the catalytic SCPNs in aqueous systems. Herein, we have developed a series of catalytic SCPNs, which possessed CO2-switchable hydrophilic/hydrophobic behavior, to realize the gas-controlled reaction and separation for asymmetric sulfa-Michael addition (SMA) in water. A novel series of CO2-switchable random copolymers were thus synthesized by copolymerization of CO2-responsive amidine derivatives with hydrophobic chiral salen FeIII monomers via reversible addition-fragmentation chain transfer polymerization. Characterization suggested their CO2-controlled self-collapse behavior in water due to CO2-switched change in hydrophilicity/hydrophobicity of the amidine moiety. The resultant CO2-switchable SCPNs provided hydrophobic, catalytic compartments for asymmetric SMA in water upon CO2 addition, giving various chiral β-keto sulfides with almost quantitative yields (90–98%) and high enantioselectivities (93–99%). When CO2 is removed by N2 bubbling, they were collapsed and spontaneously precipitated from the aqueous system for steady reuse. The gas-controlled reaction-separation approach provides an energy-efficient way to combine reactivity and recovery of catalytic SCPNs in aqueous systems, which should be quite practical in large-scale industrial applications.

Aggregation-Induced Emission: Together We Shine, United We Soar!

Abstract: Ju Mei,†,‡,∥ Nelson L. C. Leung,†,‡,∥ Ryan T. K. Kwok,†,‡ Jacky W. Y. Lam,†,‡ and Ben Zhong Tang*,†,‡,§ †HKUST-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China ‡Department of Chemistry, HKUST Jockey Club Institute for Advanced Study, Institute of Molecular Functional Materials, Division of Biomedical Engineering, State Key Laboratory of Molecular Neuroscience, Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China Guangdong Innovative Research Team, SCUT-HKUST Joint Research Laboratory, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China

Old materials with new tricks: multifunctional open-framework materials.

Abstract: The literature on open-framework materials has shown numerous examples of porous solids with additional structural, chemical, or physical properties. These materials show promise for applications ranging from sensing, catalysis and separation to multifunctional materials. This critical review provides an up-to-date survey to this new generation of multifunctional open-framework solids. For this, a detailed revision of the different examples so far reported will be presented, classified into five different sections: magnetic, chiral, conducting, optical, and labile open-frameworks for sensing applications. (413 references.)

Development of Dendrimers: Macromolecules for Use in Organic Light-Emitting Diodes and Solar Cells

Abstract: Introduction: Branched macromolecules or dendrimers have provided a rich seam of research in terms of both innovative chemistry and applications.1-14 For example, dendrimers have been studied for use as low-dielectric materials,15 as templates for the growth of single-wall carbon nanotubes,16 as catalysts,17-19 and in biological applications,20-23 including biosensors,24 magnetic resonance imaging,25-28 and drug delivery.29-33 However, it has only been more recently that such macromolecular structures have been explored in terms of their electronic and optoelectronic properties, which is the focus of this series of reviews. For example, charge-transporting dendrimers have become an important class of organic semiconducting material34 and significant effort has focused on light harvesting and energy transfer from a peripheral dye or chromophore to an emissive dye at the center or focus of the dendrimer.35-39 Organic semiconductors have become increasingly important as the active component in applications including organic light-emitting diodes (OLEDs),40-42 transistors,43,44 photovoltaic (PV) cells,45,46 optical amplifiers,47,48 and lasers.49-51 Traditionally, organic semiconductors have fallen into two main classes, small molecules and polymers, and these materials and their applications will be covered in detail by other authors. Small molecules are generally processed by evaporation techniques and have the advantages that the structure−property relationships are relatively simple to understand, the materials are mono(disperse), and they are deposited in a pure form. On the other hand, conjugated polymers are soluble and can be deposited from solution by processes such as spin-coating and ink-jet printing, which opens up the exciting prospect of simple, fast, large-area, low-temperature device manufacturing. An additional advantage for conjugated polymers is that solution processing is potentially less wasteful of material than evaporation for devices that require patterning. However, it is often difficult to control the polydispersity, molecular weight, backbone defects, and end groups of conjugated polymers reproducibly. Branched macromolecules, known as dendrimers, also have the advantage of being solution processable but by careful design can incorporate the control over the optoelectronic properties that is reminiscent of small molecules. In addition, the dendritic architecture provides a number of other attractive properties, including the ability to independently control the processing and optoelectronic properties; providing the processing power to enable simple chromophores to be deposited as stable amorphous films; dendrimer generation as a tool for controlling the intermolecular interactions that govern device performance; and the ability in well-defined dendrimers to have high chemical purity. In this review, we will focus on synthetic strategies that have been investigated for the preparation of optoelectronically active solution-processable dendritic materials and concentrate on two different applications, namely OLEDs and solar cells, in which they have been used. In the context of OLEDs, we limit the discussion to light emission, as branched macromolecules for charge transport will be discussed in the review by Shirota. We will also briefly comment on other recent light-emitting and -absorbing branched molecular materials that have been used in OLEDs and solar cells.

Materials for organic electroluminescent devices

Abstract: The present invention relates to compounds of the formula (1) which are suitable for use in electronic devices, in particular organic electroluminescent devices, and to electronic devices which contain these compounds.

Electron-transporting materials for organic electroluminescent and electrophosphorescent devices

Abstract: One of the requirements for efficient organic electroluminescent devices (OLEDs) is balanced charge injection from the two electrodes and efficient transport of both holes and electrons within the luminescent layer in the device structure. Many of the common luminescent conjugated polymers, e.g. derivatives of poly(phenylenevinylene) and poly(fluorene), are predominantly hole transporters (i.e. p-dopable). This article gives a brief overview of organic electroluminescence and electrophosphorescence and provides a more detailed consideration of ways in which electron transport in these systems has been enhanced by the incorporation of electron-deficient (i.e. n-dopable) small molecules and polymers into the devices, either as blends or by covalent attachment of sub-units to the luminophore or as an additional electron-transporting, hole-blocking (ETHB) layer adjacent to the cathode. The chemical structures of these systems are presented and their roles are assessed. Most of these ETHB molecules are electron-deficient aromatic nitrogen-containing heterocycles, e.g. derivatives of 1,3,4-oxadiazole, pyridine, pyrimidine, pyrazine, quinoline, etc. Non-aromatic thiophene-S,S-dioxide derivatives are also discussed. The article is written from an organic chemist's perspective.