Synthesis And The Recognition Properties Of Schiff Base Receptors Based On Naphthalene As The Fluorescent Chromophore

This paper includes four chapters:Chapter 1: This chapter describes the nature of the host-guest supramolecular chemistry interaction, the study identified the significance of the metal cations, and the latest research progress to identify the metal cation. The identification process of different fluorescent chromophores, will be divided into six categories:（1） to naphthalene cation fluorescent acceptor chromophore;（2） to the coumarin ring cationic fluorescent chromophores receptor;（3） to rhodamine B or fluorescein as the fluorescent chromophore cation receptor;（4） pyrene as a fluorescent chromophore cation receptor;（5） in N, N- diethylamino salicylaldehyde or julolidine salicylaldehyde fluorescent chromophore cation receptor;（6） based on a cation other fluorescent acceptor chromophores.Chapter 2: A fluorescent mercury sensor allowing for cheap, sensitive, and highly selective detection of Hg²⁺ is described. This sensor combines two naphthalene groups as signaling subunits and the presence of imine group which was oxidized to amide with DMSO and Hg²⁺ confers the coordination capacity required to coordinate Hg²⁺ ion. This double-naphthalene Schiff base chemosensor（G） is readily soluble in DMSO and the solution give colorless fluorescent signal, when sensor G reacts with Hg²⁺ the solution give blue fluorescent signal. The MS, IR and ¹H NMR data suggest that the presence of Hg²⁺ leads to the formation of O-Hg²⁺-N, which is then converted to a structural change, the C=N of G was oxidized to O=C-NH. The test strip based on G was fabricated, which could act as a convenient and efficient Hg²⁺ test kit. The event is useful for fluorescent detection of Hg²⁺ at the micromolar level with a detection limit of 5.595×10-8 M in DMSO medium.Chapter 3: A double naphthaline Schiff-Base example of the nonsulfur, simple, highly selective and two channel mercury ions chemosensor was designed according to the twisted intramolecular charge transfer（TICT） mechanism. This work provides a novel approach for selective recognition of mercury ions. Moreover, The sensor could serve as a potential recyclable component in sensing materials and the complex G1-Hg²⁺ could therefore be used as an ON-OFF fluorescent switch chemosensor for iodine anion candidate. Notably, the color changes are so obvious that all of the recognizing and recycling processes can be seen clearly by the naked eye.Chapter 4: A novel chemosensor G₂ based on furfural derivatives was described, which could detect Fe³⁺ in aqueous solution with specific selectivity and high sensitivity. The addition of Fe³⁺ to sensor G₂ induced a remarkable blue fluorecence via chemical reaction; this sensing procedure could not be interfered by other coexistent competitive cations such as Hg²⁺, Cu²⁺, and Cd²⁺. Thus G₂ could be used as a potential Fe³⁺ fluorescence probe. The detection limits could reach 1.89×10-7 M. Moreover, test strips based on sensor G₂ were fabricated, which could act as a convenient and efficient Fe³⁺ test for ?in-the-field‘ measurement of Fe³⁺.