A Ratiometric Fluorescent Probe for K+ in Water Based on a Phenylaza-18-Crown-6 Lariat Ether

作者：Schwarze Thomas; Riemer Janine; Holdt Hans Juergen^*

来源：Chemistry - A European Journal, 2018, 24(40): 10116-10121.

DOI：10.1002/chem.201802306

• charge transfer
• crown compounds
• fluorescence
• potassium
• ratiometric sensors

This work presents two molecular fluorescent probes 1 and 2 for the selective determination of physiologically relevant K+ levels in water based on a highly K+/Na+ selective building block, the o-(2-methoxyethoxy)phenylaza-18-crown-6 lariat ether unit. Fluorescent probe 1 showed a high K+-induced fluorescence enhancement (FE) by a factor of 7.7 of the anthracenic emission and a dissociation constant (K-d) value of 38mm in water. Further, for 2+K+, we observed a dual emission behavior at 405 and 505nm. K+ increases the fluorescence intensity of 2 at 405nm by a factor of approximately 4.6 and K+ decreases the fluorescence intensity at 505nm by a factor of about 4.8. Fluorescent probe 2+K+ exhibited a K-d value of approximately 8mm in Na+-free solutions and in combined K+/Na+ solution a similar K-d value of about 9mm was found, reflecting the high K+/Na+ selectivity of 2 in water. Therefore, 2 is a promising fluorescent tool to measure ratiometrically and selectively physiologically relevant K+ levels.

• 出版日期2018-7-17