A Highly Selective and Sensitive Fluorescent Chemosensor for Hg²⁺ in Neutral Buffer Aqueous Solution

A selective and sensitive fluorescent chemosensor for Hg2+, which was composed of two aminonaphthalimide fluorophores and a receptor of 2,6-bis(aminomethyl)pyridine, was synthesized through the reaction of 2,6-bis(chloromethyl)pyridine and N-[2-(2-hydroxyethoxy)ethyl]-4-piperazino-1,8-naphthalimide. The chemosensor showed an about 17-fold increase in fluorescence quantum yield upon addition of 1 equiv of Hg2+ in neutral buffer aqueous solution, and the other common metal ions did not notably disturb the detection of Hg2+

Surface activities and thermodynamic properties of novel cationic surfactants with hydroxymethyl group

<p>A new series of cationic surfactants, <i>N</i>–alkyl–<i>N,N</i>–dimethyl–<i>N</i>–(<i>p</i>–(hydroxymethyl) benzyl) ammonium chlorides (<i>p</i>-DHBA<i>-m</i>), were synthesized and the structures were characterized by ¹HNMR, ¹³CNMR, FT–IR and ESI–MS. The surface activities, thermodynamic properties and aggregation behaviors of <i>p</i>-DHBA<i>-m</i> in aqueous solutions were respectively studied by means of surface tension, isothermal titration calorimetry and steady-state fluorescence methods. Thermodynamic parameters show that the micellization is an entropy-driven process. According to the fluorescence quenching method, the micelle aggregation numbers (<i>N</i>_agg) of <i>p</i>-DHBA-<i>m</i> were calculated and found that the increase of temperature or the elongation of alkyl chain length could lead to the reduction of the <i>N</i>_agg, respectively.</p

Ratiometric and Water-Soluble Fluorescent Zinc Sensor of Carboxamidoquinoline with an Alkoxyethylamino Chain as Receptor

A novel “naked-eye” and ratiometric fluorescent zinc sensor (AQZ) of carboxamidoquinoline with an alkoxyethylamino chain as receptor was designed and synthesized. AQZ shows good water solubility and high selectivity for sensing; about an 8-fold increase in fluorescence quantum yield and a 75 nm red-shift of fluorescence emission upon binding Zn2+ in buffer aqueous solution are observed. Moreover, AQZ can enter yeast cells and signal the presence of Zn2+