Preparation And Properties Of Optical Chemosensing Materials Based On Rhodamine And Naphthalimide

Optical chemsensor was extensively used in environmental, biological and medicalfields due to its advantages such as high sensitivity, high selectivity, easy synthesis andfast detection. Based on the researches and results reported recent years, we have designedand fabricated a series of chemosensors based on rhodamine and naphthalimide with theirspectrum properties studied. The main components are as follows:1. Chemosensor based on adamantane-modified rhodamine was designed andassemblied with cyclodextrin-modified magnetic microspheres via the host-guestinteractions, thus a reusable, colorimetric chemosensor for Cu2+was gained. Thechemosensor can detect Cu2+with naked-eye and quantitative spectrometric analysis. Thedetection limit can reach to5.99×10-6M and20μM for naked-eye. The recycling of themicrospheres can be achieved by removing the rhodamine moiety from the surface of themagnetic microspheres via changing the solvent after the testing. Otherwise themicrospheres can separate the metal ions from the solvent by the interactions betweenhydroxyl groups of the cyclodextrin and metal ions. This multifunctional material has notbeen reported till now.2. A fluorescent and colorimetric chemosensor for Cu2+based on the assembly ofisothiocyanate azobenzene-modified rhodamine and cyclodextrin-modified magneticmicrospheres via host-guest interactions was designed and fabricated. The detection limitcan reach to2.5×10-7M and the chemosensor can be recycled by changing thecomposition of the solvent.3. We designed and synthesized a rhodamine-Cu2+complex type fluorescent sensorfor CN-based on the strong coordinating capability between Cu2+and CN-. CN-bindedwith Cu2+which induced a dissociation of the rhodamine-Cu2+complex. This can changethe structure of rhodamine along with a color change from pink to colorless and a reduction of the UV-vis spectra absorbance. The detection limit can reach to5.68×10-6M.Otherwise we got test papers by assembling the chemosensor and the nanofibers graftedwith β-cyclodextrin via host-guest interactions. The nanofibrous test papers showedcolorimetric detection ability for CN-and the detection limit by naked eye is10-20μM.4. A deprotonation-type fluorescent chemosensor for F-was synthesized. Thefluorophore was naphthalimide and the receptor unit was isothiocyanate. The PET processwas changed via the deprotonation of chemosensor by F-. It has high sensitivity andselectivity for F-ions with fast response and the detection limit is1.21×10-6mol/L. Afterassembling with crosslinked α-CD/PVP electrospun nanofibers, a functionalizedfluorescent nanofiber for F-has been fabricated. This nanofiber can be used for rapiddetection for F-.