PKa modulation of rhodamine alkylamides by hydrogen-bond and application in bio-imaging. (April 2021)

• Record Type: Journal Article
• Authors: Min, Lei; Li, Xintong; Zhang, Weiliang; Zhang, Xinfu; Zhang, Ying; Yu, Haibo; Xiao, Yi
• Is Part Of: Dyes and pigments. Volume 188(2021)
• Publication Date: 2021-04
• Subjects: Rhodamine alkylamides -- Hydrogen bond -- pKa tuning -- Fluorescent probe -- Lysosome imaging; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2021.109173
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: To confirm the pKa regulation by hydrogen bond, a series of rhodamine alkylamides were developed, and their pKa values were measured in aqueous solution. For Rh-APD, intramolecular hydrogen bond derived from hydroxyl of 2-amino-1, 3-propanediol between carbonyl of spirolactam was favorable to the increase of pKa values (pKa 5.7). Gaussian stimulation demonstrated a moderate intramolecular hydrogen bond in Rh-APD at DFT/B3LYP/6–31 G(d) level. Except for pH, neither protic/aprotic solvents nor metal ions induced ring-opening transformation of Rh-APD. Bio-imaging showed that Rh-APD could specifically accumulate in lysosomes and evaluate lysosomal pH fluctuation in living MCF-7 cells. Moreover, Rh-APD also can indicate the acidity of gut and ovary of Daphnia magna. Rh-APD would be a potential reagent for water-quality monitoring with the help of its pH indication in living cells and water fleas. Graphical abstract: Image 1 Highlights: A series of rhodamine alkylamides were developed to assess the effects of hydrogen-bonding assistance for pKa regulation. The pKa value of Rh-APD was up to 5.77 (±0.02), larger 1.2 pH units than that of Rh-AP. Gaussian stimulation demonstrated a moderate intramolecular hydrogen bond in Rh-APD at DFT/B3LYP/6–31 G(d) level. Rh-APD can specifically accumulate in lysosomes and evaluate lysosomal pH fluctuation in living MCF-7 cells. Rh-APD also can indicate the acidity of gut and ovary of Daphnia magna.