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

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

"United we stand, divided we fall."--Aesop. Aggregation-induced emission (AIE) refers to a photophysical phenomenon shown by a group of luminogenic materials that are non-emissive when they are dissolved in good solvents as molecules but become highly luminescent when they are clustered in poor solvents or solid state as aggregates. In this Review we summarize the recent progresses made in the area of AIE research. We conduct mechanistic analyses of the AIE processes, unify the restriction of intramolecular motions (RIM) as the main cause for the AIE effects, and derive RIM-based molecular engineering strategies for the design of new AIE luminogens (AIEgens). Typical examples of the newly developed AIEgens and their high-tech applications as optoelectronic materials, chemical sensors and biomedical probes are presented and discussed.

Aggregation-Induced Emission: The Whole Is More Brilliant than the Parts

Keywords: Time-Resolved Fluorescence ; Resonance Energy-Transfer ; Near-Infrared Luminescence ; Double-Stranded Dna ; Prostate-Specific Antigen ; Photoinduced Electron-Transfer ; Europium-Tetracycline Complex ; Sybr-Green-I ; Terbium Complexes ; Optical Probes Reference EPFL-ARTICLE-149396doi:10.1021/cr900362eView record in Web of Science Record created on 2010-06-17, modified on 2017-05-12

Lanthanide Luminescence for Biomedical Analyses and Imaging

Design strategies for water-soluble small molecular chromogenic and fluorogenic probes.

Supramolecular Chirality in Self-Assembled Systems

Anti-aromatic compounds, as well as small cyclic alkynes or carbynes, are particularly challenging synthetic goals. The combination of their destabilizing features hinders attempts to prepare molecules such as pentalyne, an 8p-electron antiaromatic bicycle with extremely high ring strain. Here we describe the facile synthesis of osmapentalyne derivatives that are thermally viable, despite containing the smallest angles observed so far at a carbyne carbon. The compounds are characterized using X-ray crystallography, and their computed energies and magnetic properties reveal aromatic character. Hence, the incorporation of the osmium centre not only reduces the ring strain of the parent pentalyne, but also converts ′ ′

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Stabilization of anti-aromatic and strained five-membered rings with a transition metal

Nanometer-sized fluorescent hybrid silica (NFHS) particles were prepared for use as sensitive and photostable fluorescent probes in biological staining and diagnostics. The first step of the synthesis involves the covalent modification of 3-aminopropyltrimethoxysilane with an organic fluorophore, such as fluorescein isothiocyanate, under N2 atmosphere for getting a fluorescent silica precursor. Then the NFHS particles, with a diameter of well below 40 nm, were prepared by controlled hydrolysis of the fluorescent silica precursor with tetramethoxysilane (TMOS) using the reverse micelle technique. The fluorophores are dispersed homogeneously in the silica network of the NFHS particles and well protected from the environmental oxygen. Furthermore, since the fluorophores are covalently bound to the silica network, there is no migration, aggregation and leakage of the fluorophores. In comparison with common single organic fluorophores, these particle probes are brighter, more stable against photobleaching and do not suffer from intermittent on/off light emission (blinking). We have used these newly developed NFHS particles as a fluorescent marker to label antibodies, using silica immobilization method, for the immunoassay of human alpha-fetoprotein (AFP). The detection limit of this method was down to 0.05 ng mL(-1) under our current experimental conditions. We think this material would attract much attention and be applied widely in biotechnology.

Nanometer fluorescent hybrid silica particle as ultrasensitive and photostable biological labels

A cyclometalated palladium-azo complex as a differential chromogenic probe for amino acids in aqueous solution.

We report herein the first study on the chemical interaction be- tween metallabenzenes and bioactive molecules. Due to its unique stereo- electronic activities, a phenanthroline- derived ruthenabenzene (RuA A3)CHCA3)CH}ClA12H8N2)- A3))Cl2 (1) selectively binds cysteine in aqueous solution at physiological pH and then undergoes a dynamic inver- sion of configuration at the Ru center. The structure of the l-cysteine-binding product of 1 has been determined by means of X-ray diffraction. The re- placement of the l-cysteine with the d form results in an inverted stereody- namic effect. Furthermore, the inver- sion process of the Ru-centered config- uration could be conveniently con- trolled by a simple pH adjustment. This is attributed to the significant in- fluence of a special intramolecular electrostatic interaction on the dynamic epimerization process of the cysteine- binding product.

pH‐Switchable Inversion of the Metal‐Centered Chirality of Metallabenzenes: Opposite Stereodynamics in Reactions of Ruthenabenzene with L‐ and D‐Cysteine

Research into transition-metal-containing metallaaromatics is attracting considerable current attention. Since the first example of metallabenzenes were reported by Roper et al. in 1982, a wide variety of monocyclic metallaaromatics have been successfully isolated and characterized. However, the chemistry of fused metallaaromatics is less developed. Most of the reported fused metallaaromatics were constructed by the cyclometalation of an unsaturated precursor. 7] Only one exceptional example, based on the metal insertion reaction of benzothiophene, has been reported. In principle, it may be another efficient approach to construct fused metallaaromatics from monocyclic metallaaromatics; however, such a possibility has not been realized to date. Herein, we report a novel annulation reaction leading to the first metallabenzothiazole 2 based on the intramolecular nucleophilic aromatic substitution (SNAr) reaction of metallabenzene 1. Furthermore, transformation of 2 to the first metallabenzoxazoles 4 and 5 is also presented (Scheme 1). It is now well-established that arenes, and especially heteroarenes, could undergo SNAr reaction if electron-withdrawing substituents are positioned ortho or para to the leaving group (typically a halogen) on the ring. Recently, we reported the synthesis of osmabenzene 1 bearing a phosphonium substituent and a reactive thiocyano group on the metallacycle. In this system, the metal center and the electron-withdrawing phosphonium group may exert significant influence on the electron density of the aromatic ring. In this regard, complex 1 might be expected to undergo intramolecular SNAr reactions to construct new metallaaromatic compounds. With this idea in mind, we studied the reaction of osmabenzene 1 with MeONa/MeOH, from which osmabenzothiazole 2 was isolated as a green solid (Scheme 1). This new product is air-stable and can be kept for several days without appreciable decomposition either in the solid state or in solution at room temperature. The structure of 2 has been confirmed by X-ray diffraction. As shown in Figure 1, it contains a perfectly planar metallabenzothiazole unit. The maximum deviation from the least-squares plane of the whole metallabenzothiazole system is 0.0096 . As expected, the lengths of the Os1 C1 (1.954(7) ) and Os1 C5 (1.953(8) ) and the C C bonds within the osmabenzene ring are within the range of those observed for other osmabenzenes. 9] The C N and C S bond lengths of the thiazole moiety are similar to those

Shunhua Li

Papers

Stabilization of anti-aromatic and strained five-membered rings with a transition metal

Nanometer fluorescent hybrid silica particle as ultrasensitive and photostable biological labels

A cyclometalated palladium-azo complex as a differential chromogenic probe for amino acids in aqueous solution.

pH‐Switchable Inversion of the Metal‐Centered Chirality of Metallabenzenes: Opposite Stereodynamics in Reactions of Ruthenabenzene with L‐ and D‐Cysteine

Annulation of Metallabenzenes: From Osmabenzene to Osmabenzothiazole to Osmabenzoxazole