Study On Synthesis And Properties Of New Chemical Molecular Probes Possessing Optical Signal Response

Fluorescent chemical probe belongs to a class of optical chemical sensors usingfluorescence to convey the chemical information changes of the interaction between theanalysis objects and sensitive moleculars, it shows good performance such as high sensitivity,good selectivity and low detection limit. It plays an important role in analytical chemistry,especially in bioanalysis. Labeling reagents or fluorescent reagents can make substratespossessing fluorescence, enabling them to improve the detection sensitivity and reduce thedetection limit. Research data indicates that the detection limit will be up to10-9and even to10-12. This is also called fluorescent probe technique. In recent years, many chemicalscientists exhibit great interests in this research field.Two series of small molecule fluorescent probes were designed and studied in this paper,including:1.9-Benzylidene-9H-fluorene as a fluorophore was introduced in the first class of smallmolecule fluorescent probes because it belongs to aryl ethylene derivatives and has largeconjugated system which affords good fluorescence emission properties. In addition，it wouldnot occur isomerization during the radiation of light due to the symmetry property of doublebond in molecular structure. We chose pyridylmethyl derivatives as acceptor with differentsubstituent group at4-position, for example,-H，-NO2，-OCH3. Since these groups willstrongly affect the electron cloud density distribution on the pyridine N atom, the designedfluorescent probes would exhibit different interaction to metal cations. Ultraviolet visiblespectra, fluorescence spectra and MALDI-TOF-MS indicated that fluorescent probe23(H-,4-position) could be used as a potential colorimetric chemosensor for Ni2+with highselectivity.2. We chose thieno[2,3-b]thiophene as fluorophore due to large conjugated system, highcloud density, good hole transmission capacity and optical properties, and benzothiazolyl asthe recognition group for the second class of fluorescent probe. In research work, we usedchloracetyl chloride to regulate the distance of luminophore and recognition group. We hopedthat the change could enhance interaction between designed probes and metal ions. Theresults show compound（31）could detect Hg2+and Zn2+ions selectively, but compound（33）exhibits special capability of selectively recognising for Hg2+. In addition, we also introducedcrown ether groups into probe with thieno[2,3-b]thiophene as fluorophore, the study revealsthat the compound (36) has good fluorescent recognition ability for Zn2+.