Highly selective fluorescent chemosensor for Zn(2+ )derived from inorganic-organic hybrid magnetic core/shell Fe(3)O(4)@SiO(2 )nanoparticles

Magnetic nanoparticles with attractive optical properties have been proposed for applications in such areas as separation and magnetic resonance imaging. In this paper, a simple and novel fluorescent sensor of Zn(2+ )was designed with 3,5-di-tert-butyl-2-hydroxybenzaldehyde [DTH] covalently grafted onto the surface of magnetic core/shell Fe(3)O(4)@SiO(2 )nanoparticles [NPs] (DTH-Fe(3)O(4)@SiO(2 )NPs) using the silanol hydrolysis approach. The DTH-Fe(3)O(4)@SiO(2 )inorganic-organic hybrid material was characterized by transmission electron microscopy, dynamic light scattering, X-ray power diffraction, diffuse reflectance infrared Fourier transform, UV-visible absorption and emission spectrometry. The compound DTH exhibited fluorescence response towards Zn(2+ )and Mg(2+ )ions, but the DTH-Fe(3)O(4)@SiO(2 )NPs only effectively recognized Zn(2+ )ion by significant fluorescent enhancement in the presence of various ions, which is due to the restriction of the N-C rotation of DTH-Fe(3)O(4)@SiO(2 )NPs and the formation of the rigid plane with conjugation when the DTH-Fe(3)O(4)@SiO(2 )is coordinated with Zn(2+). Moreover, this DTH-Fe(3)O(4)@SiO(2 )fluorescent chemosensor also displayed superparamagnetic properties, and thus, it can be recycled by magnetic attraction.