Development of a new rhodamine 6G based probe and its application as an optical sensor of Cu2+ and Fe3+ ions: A comprehensive experimental and Theoretical studies

Abstract

A new rhodamine appended probe 3-allyl salicylaldehyde rhodamine hydrazone (RGAL) has been synthesized and thoroughly characterized using various spectroscopic techniques, as well as single crystal XRD. The optical properties of RGAL were investigated in 10 mM HEPES buffer in H2O:CH3CN (2:8, v/v, pH=7.2) in the presence of various cations. RGAL showed selectivity and sensitivity towards Cu2+ during absorption process and “turn on” behavior towards Fe3+ during emission study owing to the opening of a spirolactum ring. The detection limits for Cu2+ and Fe3+ ions using RGAL were determined to be 6.15 ppm and 4.75 ppm, respectively. The binding constant of RGAL with Cu2+ and Fe3+ ions was found to be 1.20 × 104 M−1 and 1.71 × 104 M−1, respectively. Hirshfeld surface and fingerprint analysis of RGAL provides the in-depth analysis of pairwise interaction between two atoms. Furthermore, the topological analysis of RGAL is performed using NCI, AIM, ELF and LOL analysis. The analysis provides information about O78-H79…N71 and C40-H41…O77 hydrogen bonding interactions in the monomer of RGAL whereas various inter- and intra- molecular interactions give strength to the dimer pattern of RGAL. © 2024 Elsevier B.V.