Synthesis And Ion Recongnition Of Fluorescence Probes Based On Quinazolin-4(3H)-one Derivatives

Molecular recognition is one of the main research contents of supramolecular chemistry,plays crucial roles in lift and information sciences.2-?2-hydroxy-phenyl?-4?3H?-quinazolinone?HPQ?,a typical compound that exhibits excited state intramolecular proton transfer?ESIPT?reaction with strong fluorescence emission.In thesis,some chelating and reactive chemosensors were designed and synthesized,and ion recognition behavior was explored according to quinazolin-4?3H?-one.1.A new 2-?2?-hydroxyphenyl?quinazolin-4?3H?-one derived acylhydrazone compound?QP?was designed and synthesized.In Tris-HCl buffer?10 mM,pH = 7.4?/ethanol?1/9,v/v?solution,QP exhibits a highly selective fluorescence response to Al³⁺ over other metal ions with a significant blue-shifted and enhanced emission at 473 nm.QP interacts with Al³⁺ reversibly through a 1:2 binding ratio with a detection limit of 4.79×10^-8 M.Potential applicability of QP for Al³⁺ detection in tap and lake water samples were also examined by ‘proof-of-concept' experiments.2.A 2-?2?-hydroxyphenyl?quinazolin-4?3H?-one derived enaminone?QA?was designed and synthesized as a fluorescent probe.In PBS buffered?10 mM,pH = 7.4?water solution,QA displays high selectivity to Pd²⁺ over other metal ions with a complete fluorescence quenching at 538 nm.Probe QA interacts with Pd²⁺ through a 1:1 binding stoichiometry with a detection limit of 4.85 × 10^-7 M.Potential applications of QA for Pd²⁺ detection in real water samples and living cell imaging were also investigated.In addition,probe QA exhibited specific selectivity towards CN-in DMSO solution with fluorescence enhancement and blue-shifted,the recognition mechanism was proved to be underwent Michael addition of CN-toward QA.In addition,the response of probe QA to CN-is very fast and the detection limit is as low as 1.75×10^-7 M.3.A dithioacetal fluorescent probe QBDA was designed and synthesized.Probe QBDA exhibits high selectivity and sensitivity to Hg²⁺ over other metal ions in PBS buffered?20 mM,pH = 7.4?solution,the recognition mechanism is Hg²⁺-triggered transformation of QBDA to precursor aldehyde.The detection limit of QBDA for Hg²⁺ was estimated to be 2.04×10^-8 M and the potential interference from Ag+ can be suppressed in PBS buffered normal saline solution.Living cell imaging investigations show that QBDA possesses good cell permeability,and can act as a light-up imaging probe for Hg²⁺ ions in MCF-7 cell.4.A 2-?2?-hydroxyphenyl?quinazolin-4?3H?-one derived?NQA?was designed and synthesized as a fluorescent probe.In PBS buffered?10 mM,pH = 7.4?water solution,NQA exhibits a single selective fluorescence response to Zn²⁺ with a significant blue-shifted and enhanced emission.Probe NQA interacts with Zn²⁺ through a 1:2 binding stoichiometry with a detection limit of 1.58 × 10^-7 M.