Chaoliang Tan

Optical and electrochemical responses of an anthrax biomarker based on single-walled carbon nanotubes covalently loaded with terbium complexes

An effective single-walled carbon nanotube (SWNT) covalently loaded with unsaturated terbium emissive material was designed for specific and rapid (2-3 s) detection of calcium dipicolinate (CaDPA) (detection limit 1 μM). The nanoprobe was successfully assembled onto electrodes and its sensing abilities were investigated through electrochemical measurement. Cyclic voltammetry curves were selectively responsive to calcium dipicolinate compared with benzoic acid, o-phthalic acid and m-phthalic acid. This novel material provides dual opto-electrochemical recognition of the anthrax biomarker CaDPA.

Anion/cation induced optical switches based on luminescent lanthanide (Tb3+ and Eu3+) hydrogels.

Two novel silica based lanthanide complexes (Tb(a)2 and Eu(a)2) were encapsulated into poly(acrylic acid) host. Both Tb(III) and Eu(III) containing hydrogels have typical and easily distinguished narrow line emissions occurring in the green and red region respectively. Particularly, the excitation wavelength for Eu complex can be extended into nearly visible light range (λex = 395 nm). Interestingly, we discover that these target materials not only exhibit selective emission response towards HSO4− (detection limit 10−5 m) compared with CH3COO−, F−, Cl−, Br− and I− but also give unique quenching to Cu2+ (detection limit 10−5 m) (tested cations: Cu2+, Pd2+, Cd2+, Co2+ and Mn2+). More importantly, this kind of materials can be recycled more than 10 times.

A luminescent lanthanide complex-based anion sensor with electron-donating methoxy groups for monitoring multiple anions in environmental and biological processes

We designed a ternary europium (III) tris(2-thenoyltrifluoroacetonate) with 2-(3,4,5-trimethoxyphenyl)imidazo[4,5-f]-1,10-phenanthroline (1) ligands for the luminescent detection of various anions, such as fluoride, acetate and dihydrogen phosphate. Characterization of the sensors photophysical properties and via NMR showed that the sensor exhibits striking emission changes to fluoride (purple), acetate (green) and dihydrogen phosphate (blue) anions, respectively. Its fluorescence lifetime was determined to be 1.10 ms for europium ions and the complex showed an overall quantum yield of 10% in DMSO. Furthermore, transparent hybrid thick films composed of the europium complex and poly-methyl methacrylate matrix were successfully prepared via copolymerization. The resulting film overall displayed intense red emissions associated with europium ions. Fluorescence microscopic evaluation showed a homogenous distribution of aggregates with average diameters of 30-50 μm throughout the film. The accordingly produced film could give rise to a luminescence change to purple in response to fluoride anions.

Luminescent Cu2+ Probes Based on Rare-Earth (Eu3+ and Tb3+) Emissive Transparent Cellulose Hydrogels

Cellulose hydrogels are biodegradable materials that can be applied as accommodating hosts for various species. Here we report the preparation of novel thin films based on luminescent cellulose hydrogels. The spectroscopic behavior of these soft materials and their sensing effects are investigated. Interestingly, we found that these films only give selective signal changes in the presence of Cu2+ in water in comparison with Na+, K+, Ag+, Mn2+, Co2+, Ca2+, Cd2+, Hg2+, Pd2+, Mg2+, Ni2+, Fe2+, and Fe3+. High visible-light transmittance and good flexibility for these films can be observed. More importantly, the thermal stability of rare-earth complexes could be significantly enhanced in aqueous solution as result of the protection by hydrogel matrix.

Anion Responsive Dibenzoyl‐l‐Cystine and Luminescent Lanthanide Soft Material

A mild sol–gel technique was used to incorporate terbium dibenzoyl‐l‐cystine complex into silica and green luminescent hybrid material was fabricated. 1H NMR and fluorescence spectroscopy revealed the hybrids can recognize F− anions through hydrogen bonding formation and had no sense in binding other halide or HSO4−. Furthermore, a luminescent hydrogel was successfully designed by immobilizing a terbium activated phosphor (Gd0.1Ce0.9PO4:Tb) into molecular hydrogelator (dibenzoyl‐l‐cystine). The Tb(III) emission in hydrogel media gave a distinguished enhancement based on temperature increase and the function conforms to exponential equation y = 1160.6 exp0.03x. The stability of the green luminescent gel was rather excellent and the reversibility of the gel can be recycled at least five times.

Anion/Cation (H2PO4− and Fe3+) induced dual luminescence quenching effect based on terbium solid sensor

Abstract An investigation on the photophysical properties of the newly designed terbium imidazole-4,5-dicarboxylic acid complex encapsulated in the inert matrices (tetraethoxysilane, TEOS) was performed. The composite material was very stable and showed strong green emission in pure water. Interestingly, we discovered that the luminescence of hybrid material was selectively responsive to H 2 PO 4 − . 1 H-NMR and fluorescence spectra supported that the receptor had strong affinity to dihydrogen phosphate. Meanwhile, the luminescence was quenched by Fe 3+ when adding different metal ions such as Fe 3+ , Pd 2+ , Cd 2+ , Co 2+ and Mn 2+ concomitantly. Moreover, thin film was successfully prepared by the same materials and it also exhibited selective recognition behavior to the above two ions.