Effect of substitution at amine functionality of 2,6-Diaminopyridine-coupled rhodamine on metal-ion interaction and self-assembly

Panja, S. , Mondal, S., Ghosh, S., Ghosh, U. and Ghosh, K. (2020) Effect of substitution at amine functionality of 2,6-Diaminopyridine-coupled rhodamine on metal-ion interaction and self-assembly. ACS Omega, 5(23), pp. 13984-13993. (doi: 10.1021/acsomega.0c01384) (PMID:32566865) (PMCID:PMC7301565)

Abstract

2,6-Diaminopyridine-coupled rhodamines 1 and 2 have been synthesized, and the effect of substitution on amine functionality toward metal-ion interactions and self-assembly is thoroughly investigated. Both the compounds effectively recognize different metal ions of biological significance fluorimetrically and colorimetrically with a high degree of selectivity and sensitivities. While compound 1 is sensitive to Fe3+ ions, compound 2 is responsive to both Fe3+ and Al3+ ions in aqueous CH3CN (4/1, v/v; 10 mM tris HCl buffer, pH 6.8). The sensing mechanism involves the metal-ion chelation-induced spirolactam ring opening of the rhodamine scaffold that results in both color and fluorescence changes, while the extent of interactions with the metal ions is truly governed by the chemical structure of the compounds. Both 1 and 2 are proficient in detecting Fe3+ and Al3+ ions in human lung cancer cells (A549). As new findings, unlike 1, compound 2 formed a faint pink gel in the toluene-hexane mixture solvent (1:1, v/v), and the gel state of 2 selectively recognizes Ag+ ions by exhibiting a phase change from gel to purple sol. Experimental findings establish the role of the formamide moiety in forming the self-assembly.

• Item Type: Articles
• Additional Information: S.P. thanks the Royal Society and SERB of India for a Newton International Fellowship. S.M. thanks UGC, New Delhi, India for fellowship. K.G. thanks SERB, DST, New Delhi, for financial support (file no. EMR/2016/008005/OC).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Panja, Dr Santanu
• Authors: Panja, S., Mondal, S., Ghosh, S., Ghosh, U., and Ghosh, K.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: ACS Omega
• Publisher: American Chemical Society
• ISSN: 2470-1343
• ISSN (Online): 2470-1343
• Published Online: 03 June 2020
• Copyright Holders: Copyright © 2020 American Chemical Society
• First Published: First published in ACS Omega 5(23): 13984-13993
• Publisher Policy: Reproduced in accordance with the publisher copyright policy