极性溶剂导致荧光增强及其单晶结构和TD-DFT计算揭示荧光增强的原理

基于阴阳离子交换反应的比率式荧光探针

Smart, chiral, and non-conjugated cyclohexane-based  bis-salicylaldehyde hydrazides: multi-stimuli-responsive, turn-on, ratiometric, and thermochromic fluorescence, single crystal structures, and DFT calculations

M. Wang, C. Q. Cheng, C. B. Li, D. H. Wu, J. T. Song, J. Wang, X. G. Zhou, H. F. Xiang*, and J. Liu,*  J. Mater. Chem. C, 2019, DOI: 10.1039/C9TC01337G.

A unique serial of smart, chiral, and multi-stimuli-responsive cyclohexane-based bis-salicylaldehyde hydrazides has been designed and prepared. Their molecular structures and alignments and fluorescence properties are highly dependent on the environment conditions. They show unusual polar solvent-, cation-, anion-, and amino acid-induced fluorescence enhancements with emission quantum yield up to 0.40. Based on single crystal structures and multi-molecule density functional theory calculations, polar solvent-induced fluorescence can be contributed to the intermolecular hydrogen bonds that would affect molecular structure, charge distribution, and transition process. Cation- and anion/amino acid-induced fluorescence are cause by the coordination and deprotonation, respectively. Through cation/anion exchange reaction, ratiometric fluorescence with extending detection range for Mg²⁺ is achieved for the first time. Thermochromic fluorescence from white into blue would be observed when temperature is increased from 77 K to room temperature. Moreover, these un-conjugated materials with a lower cytotoxicity and better biocompatibility have the potential application in cell imaging and chiral recognition.