Synthesis Of Biscarbony1Hydrazone And Thiosemicarbazone Receptors And The Recognition Properties

This paper includes four chapters:Chapter One:This one is about the research of recognition in recent years. Including three parts:(Ⅰ) research anions recognition;(Ⅱ) research cations recognition;(Ⅲ) research continuity recognition.Chapter Two:a novel copper selective sensor L2based on hydrazide and salicylaldehyde has been designed and prepared. Sensor L2behaves a single selectivity and sensitivity in the recognition for Cu2+over other metal ions such as Fe3-, Hg2-, Ag-, Ca2+, Zn2+, Pb2+, Cd2-, Ni2-, Co2+, Cr3+and Mg2+in DMSO. The distinct color change and the rapid changement of fluorescence emission provide naked-eyes detection for Cu2+. The UV-vis data indicate that1:2stoichiometry complex is formed by sensor L2and Cu2+. The association constant Ks was3.51×104M-1. The detection limitation of Cu2+with the sensor L2was2.2×10-7mol L-1. The sensing of Cu2+by this sensor was found to be reversible, with the Cu2--induced color being lost upon addition of EDTA.Chapter Three:by applying an indirect strategy, a new copper (Ⅱ) complex of a thiosemicarbazone L4has been successfully developed as a colorimetric chemosensor for the sensitive detection of mercury (Ⅱ) ions. In the presence of copper (Ⅱ) ions, the colorless solution of L4became yellow; however, upon the addition of traces of mercury (Ⅱ) ions, the yellow color faded to colorless immediately. Other ions, including Fe3-, Ag+, Ca2-, Zn2+, Pb2+, Cd2+, Ni2+, Co2-, Cr3+and Mg2+had a negligible influence on the probe behavior. Sensor L4-Cu behaves a single selectivity and sensitivity in the recognition for CN-over other anions in DMSO.The detection limits were5.0×l0-6M and3.0×10-7M of Hg2+using the visual color changes and UV-vis changes respectively. Test strips based on L4-Cu were fabricated, which could act as a convenient and efficient Hg2+test kits.Chapter Four:in this paper, a new anion receptor L5containing acylhydrazone and dodecyloxy group had been designed and synthesized. It could selectively recognize fluoride among different anions tested with color changes from pale yellow to red for visual detection in DMSO. Simultaneously, it could gel in DMF, and the gel was also fluoride-responsive. When treated with TBAF (tetra-n-butylammonium fluoride), the gel could undergo gel-sol transition accompanied by color and morphology changes. Field emission scanning electron microscopy (FESEM) showed the formation of well-developed three-dimensional networks composed of interlocked fibers. Also, it was indicated that the addition of F-could destroy the molecule assembly of host L5in the gel state, thus resulting in the gel-to-sol transition due to the binding site competition effect. The gel exhibited outstanding reversible sol-gel transitions induced by F-and acid/base exchange and could be applied in molecular switches in the future. To the best of our knowledge, this was the simplest fluoride-responsive organogel with high selectivity. Moreover, this gel shows efficient absorption ability of malachite green oxalate dye molecule in aqueous solution.