Synthesis Of π-Conjugated Xanthene Probes For Sensing Properties

Traditional xanthene dyes are widely used in the design and synthesis of molecular probes,but their absorption and emission are limited by the energy change process of side chains,they are susceptible to interference from auto-fluorescence of biological tissue in vivo imaging.From the point of the extendedπ-conjugation system of parent and side-chain,a series of colorimetric probes and fluorescent probes were developed,and their spectroscopic properties were investigated in this paper.The specific contents of this paper are as follows:Aπ-extended rhodamine derivative aminobenzopyranoxanthene（ABPX）was synthesized,and then ABPX reacted with hydrazine monohydrate to give ABPX-hydrazide（ABPX-hy）,which can detect Hg²⁺rapidly and sensitively in ethanol solution.Based on this work,a colorimetric probe ABPX-Sal with the dispirohydrazone structure and two sensing molecules A-T1 and A-T2 with bichromophores were developed.The xanthene based probes operating without spirolactam ring opening process is still very scarce.Probe ABPX-Sal could interact with Cu²⁺by a special spiroring-closed coordination process.The spectral characteristics of ABPX-Sal were investigated by UV-Vis spectrum,and the special mechanism was verified by DFT calculations and ESI-MS tests.The detection limit of ABPX-Sal to Cu²⁺was lower than 0.912μM,enabling detection of Cu²⁺in real water samples.Two sensing molecules A-T1 and A-T2 with bichromophores were synthesized by linking different numbers of TPE units to xanthene platform（ABPX）.There was a big difference in symmetry and sensing features between A-T1 and A-T2.The UV-Vis absorption and fluorescence spectra were used to study the recognition of metal ions and acid gas sensing.These probes also could be applied as fluorescence indicators in vivo imaging with high resolution.