[en] A simple propargylamide-fuctionalized chemodosimeter was prepared for the ratiometric fluorescence detection of mercuric ions in HEPES buffer. The chemodosimeter exhibited Hg²⁺-induced propargyl amide-tooxazole transformation, with a significant accompanying ratiometric change in fluorescence. It afforded high selectivity for mercuric ion detection without any competitive inhibition by common alkali, alkaline earth, or other transition metal ions. The probe showed a 17 x 10^-6 M detection limit for Hg²⁺ ions and potential applicability for detecting aqueous Hg²⁺ ions

[en] We have developed molecular switching system triggered by oxalate anion operating on platinum square planar coordination plane by controlling well-known alkyl inversion process on nitrogens. This work shows that oxalate anion disturbs the thermodynamic equilibrium between syn and aniti conformer and induces the syn conformer to be produced in excess. Thus oxalate may be regarded as a trigger that bring about the conformational change of complex 1. This behavior might be exploited to develop sensors for the kidney stone disease-related oxalate anions. A molecular conformational switching has been of growing interest in association with molecular electronics, machines and sensors. External stimuli such as a transition metal, light, a redox reaction, pH variation and guest molecules were used to control the thermodynamic equilibrium between the conformers. For example, complexation with lewis acid, TiCl₄, changes the conformation of arene-dicarboxamide from syn to anti atropisomer. The specially designed ligand is programmed to have syn conformer by the application of the transition metal complex PdCl₂(PhCN)₂. N-Alkyl-substituted-ethylenediamine complexes of platinum(II) are well known to adopt syn and anti conformers which are inter-converted fast in aqueous solutions. We have been interested in developing a conformational switching system by exploiting this behavior, thus designed complex with two uryl groups which are well known to bind carboxylates. We speculated that the thermodynamic ratio of syn to anti conformer of would be influenced by a suitable dicarboxylate anion such as oxalate which is a biologically important anion