Designing And Recognition Studies Of Copper Ion And Zinc Ion Chemosensors

Copper and zinc are found as the essential elements in the physiology of human beings, and play an important role in our life. However, under overloading conditions, the increasing concentration of Cu2+ in body causes imbalance in cellular processes, resulting in pathogenesis. Cu has been suspected to cause infant liver damage in recent years. Similarly, inadequate zinc(II) absorption, increased zinc(II) losses from the body, or increased requirements for zinc(II) will result in zinc(II) deficiency in human organisms, which leads to several disorders such as growth retardation, the decrease of the immunological defense, eye lesion, and some skin diseases. Thus, to maintain the normal operation of the organism, seeking more effective methods of detection of copper and zinc ions quickly becomes more and more important.Fluorescein derivatives are a kind of very important fluorescent dye. They have good optical physics properties, such as large molar extinction coefficients, high fluorescence quantum yields, good light stability, non-toxic, low cost, becoming the common choice for the design of fluorescent probes.In recent years, we also developed some commercially available chemosensors to detect metal ions directly. This method is convenient and quick in detecting ions.In this thesis, we designed a pyridoxal-based fluorescein derivative, which is the second dual mode probe discovered in our group, as well as a pyridoxal-based derivative. Through the experiments we found that the two derivatives also can achieve the detection performance with high sensitivity and good selectivity. At the same time we also developed a commercially available chemosensor 1,8-diamino naphthalene, which can be directly used for sensitive and efficient detection of copper ions. The thesis work is:1. Pyridoxal-based fluorescein derivative is a new fluorescent probe. It was synthesized by a one-step reaction between fluorescein hydrazine and pyridoxal hydrochloride in ethanol containing acetic acid. Based on UV-visible absorption spectra, we found that the new probe we designed can well test Cu2+, the detection limit of 10-7 M. The color of the solution is changed, from colorless to yellow. At the same time, in the fluorescence spectrum it can be used to test Zn2+, with the detection limit of 10-8M. This is a sensor that is capable of detecting Cu and Zn using two different modes.2. We designed a pyridoxal-based derivative, the probe itself is colorless. When adding copper ions, due to the coordination of the probe and Cu2+, the color of the solution is changed from colorless to yellow. It is a efficient and specific probe for the identification of Cu2+.3.1,8-diamino naphthalene in aqueous solution has a very strong fluorescence. When adding copper ions, the fluorescence of probe was quenched by the paramagnetic effect from spin-orbit coupling of the Cu2+ after the coordination with Cu. The probe can be used to react to Cu in live cells, providing a potentially powerful approach for probing Cu2+ chemistry in biological systems.