Self-Assembled Triphenylphosphonium-Conjugated Dicyanostilbene Nanoparticles and Their Fluorescence Probes for Reactive Oxygen Species

We report self-assembled novel triphenylphosphonium-conjugated dicyanostilbene-based as selective fluorescence turn-on probes for 1O2 and ClO−. Mono- or di-triphenylphosphonium-conjugated dicyanostilbene derivatives 1 and 2 formed spherical structures with diameters of ca. 27 and 56.5 nm, respectively, through π-π interaction between dicyanostilbene groups. Self-assembled 1 showed strong fluorescent emission upon the addition of 1O2 and ClO− compared to other ROS (O2−, •OH, NO, TBHP, H2O2, GSH), metal ions (K+, Na+), and amino acids (cysteine and histidine). Upon addition of 1O2 and ClO−, the spherical structure of 1 changed to a fiber structure (8-nm wide; 300-nm long). Upon addition of 1O2 and ClO−, the chemical structural conversion of 1 was determined by FAB-Mass, NMR, IR and Zeta potential analysis, and the strong emission of the self-assembled 1 was due to an aggregation-induced emission enhancement. This self-assembled material was the first for selective ROS as a fluorescence turn-on probe. Thus, a nanostructure change-derived turn-on sensing strategy for 1O2 or ClO− may offer a new approach to developing methods for specific guest molecules in biological and environmental subjects

In Situ Supramolecular Gel Formed by Cyclohexane Diamine with Aldehyde Derivative

Low-molecular-weight gels have great potential for use in a variety of fields, including petrochemicals, healthcare, and tissue engineering. These supramolecular gels are frequently metastable, implying that their properties are kinetically controlled to some extent. Here, we report on the in situ supramolecular gel formation by mixing 1,3-cyclohexane diamine (1) and isocyanate derivative (2) without any catalysis at room temperature in various organic solvents. A mixture of building blocks 1 and 2 in various organic solvents, dichloromethane, tetrahydrofuran, chloroform, toluene, and 1,4-dioxane, resulted in the stable formation of supramolecular gel at room temperature within 60–100 s. This gel formation was caused by the generation of urea moieties, which allows for the formation of intermolecular hydrogen-bonding interactions via reactions 1 and 2. In situ supramolecular gels demonstrated a typical entangled fiber structure with a width of 600 nm and a length of several hundred μm. In addition, the supramolecular gels were thermally reversible by heating and cooling. The viscoelastic properties of supramolecular gels in strain and frequency sweets were enhanced by increasing the concentration of a mixed 1 and 2. Furthermore, the supramolecular gels displayed a thixotropic effect, indicating a thermally reversible gel

Bis(naphthol)-based fluorescent chemoprobe for cesium cation and its immobilisation on silica nanoparticle as a high selective adsorbent

<p>A bis(naphthol)-based cation receptor <b>1</b> has been synthesised by three steps of synthetic procedure. The spectroscopic properties of <b>1</b> upon addition of various metal ions were investigated by UV–vis absorption and fluorescence spectroscopy. As a result, the absorption of <b>1</b> was linearly decreased as a function of concentration of added Cs⁺. Also, <b>1</b> exhibited dramatic fluorescence quenching effect upon exposure to caesium cation. Contrastively, no significant quenching effect was observed upon addition of other metal ions such as Na⁺, K⁺, Rb⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Ni²⁺ and Zn²⁺. It was found that <b>1</b> formed a 1:1 complex with Cs⁺ by Job’s plot. Furthermore, we also prepared <b>1</b>-functionalised silica nanoparticle (<b>SiO</b>_<b>2</b><b>-1</b>) as an adsorbent for Cs⁺. <b>SiO</b>_<b>2</b><b>-1</b> showed a great capacity for selective removal of caesium ion from aqueous solution as well as from tap water. Thus, it is potentially useful for the detection and removal of caesium cation from environmental and biological fluids polluted by nuclear radiation and nuclear waste.</p