Synthesis And Application Of Ferrocenvl Chemosensors Sensing Metal Cations

Four chemosensor molecules sensing metal cations, A, B, C and E, was synthesized from ferrocene by sequential reactions, including Friedel-Crafts acylation, Haloform reaction, Esterification, Amidolysis of esters and Nucleophilic addition of aldehydes and amines.'H-NMR and mass spectrometry was carried out to research molecular weight and structure of these chemosensors. Ferrocenyl group acts as redox centers of the chemosensor molecules, while different aromatic groups containing nitrogen atom and oxygen atom endow the chemosensors with fluorescence and the binding affinity toward metal cations. Therefore the four molecules mentioned-above could be used as multichannel receptors to recognise metal cations via chromogenic, fluorogenic, and electrochemical methods.Sensing properties of the four new recepters was examined through UV-visible, fluorescence spectrum and cyclic voltammetry. Chemosensor A demonstrated selective recongnition of Ni²⁺ over a range of other metal ions. After the additon of Ni²⁺, the high energy band of the absorption spectrum of A was red-shifted ???=13nm? and the oxidation redox peak was anodically shifted?AEpa=53mV?. Chemosensor B could bind with Cu²⁺ selectively. The high energy band of the absorption spectrum was red-shifted ???=44nm? and the oxidation redox peak was anodically shifted?AEpa=33mV? upon the combination of B and Cu²⁺, meanwhile, the luorescence intensity of B increased obviously. When it came to chemsensor C, unfortunately, the presence of all kinds of metal cations could not induce any change of the absorption, emission spectrrum or redox potential, which indicated that chemsensor C may be not a potential guests towards ions.When Cu²⁺ and Ni²⁺ was added, significant changes occurred to absorption spectrum, emission spectrum and oxidation potential of chemosensor D. When chemosensor D was binding with Cu²⁺, the high energy band of the absorption spectrum of A was red-shifted ???=11nm? and the oxidation redox peak was anodically shifted?AEpa=43mV?, and fluorescence intensity increased by 0.46 times. However, When Ni²⁺ was added, the high energy band of the absorption spectrum of D was red-shifted ???=21nm? while the oxidation redox peak was anodically shifted?AEpa=1933mV?, fluorescence intensity increased by 0.33 times as well. By comparison, Chemosensor D possesed high responsing extent towards Ni²⁺ than Cu²⁺, which might be utilized to distinguish Cu²⁺ and Ni²⁺...