Synthesis And Properties Of Ion Receptors Based On Imidazole Derivatives

Over the last few years, design and synthesis of chemosensors for binding metal ions and anions selectively has attracted much attention because of the fundamental role of metal ions and anions in a wide range of medicine, biological and chemical processes. In particular, studies on metal ions and anions sensors using electrochemical change, fluorescent change or colorimetric change has been actively studied.Imidazole was widely used as a building block in the process of designing and synthesizing of chemosensors. It contains a single N-H hydrogen bond donor, which is better hydrogen bond donor to study of anion recognition by their strong H-bonding capacity. And it also could be used as a bridge to connect the ion recognition group or coordination group.Herein, We designed and synthesized a series of fluorescent sensors, in which the imidazole was fused by diarylethene and1,10-phenanthroline, respectively. The detailed contents are depicted as follows-.1. Dithienylethene derivatives containing imidazo[2,1-a]isoquinolines were directly synthesized by treatment of the diketone with2-ethynylbenzaldehyde in one pot. Their photochromism indicated that they can easily isomerize between the ring-open and ring-closed isomers upon irradiation with UV or visible light. At the same time, they display high selectivity towards Fe3+by the fluorescence titration, such that the addition of Fe3+can obviously suppress their fluorescence intensity.2. A new imidazo[4,5-f]-1,10-phenanthroline ligand and its Pt (Ⅱ)-, Ru (Ⅱ)-, Re (I) derivatives have been synthesized. It is shown that these metal complexes can be used as colorimetric and fluorescence chemosensors for anions. The interaction of these complexes with different anions has been characterised by UV/Vis absorption spectra, fluorescence spectra and titration studies. The results indicated that the three complexes all showed selective recognition for F-.