Solvatochromic shift and estimation of dipole moment of synthesized coumarin derivative: Application as sensor for fluorogenic recognition of Fe3 + and Cu2 + ions in aqueous solution

Abstract

(S)-4-((4-((3-amino-2-oxo-4-phenylbutoxy)methyl)-1H-1,2,3-triazol-1-yl)methyl)-7 hydroxy-2H-chromen-2-one hydrochloride was synthesized and characterized by detailed spectroscopic studies such as 1H, 13C NMR and HRMS. Excited state dipole moment of synthesized compound was obtained using different solvatochromic shift methods. High value of dipole moment is observed for excited state as compared to ground state value and this is attributed to more polar excited state of molecule. Also, fluorescence emission peak undergoes a bathochromic shift with increase in the polarity of the solvent, confirming π→π* transition. The potential sensor behavior of the compound to metal ions has also been examined. Chemosensor shows the sensitivity for Fe3+ and Cu2+ over other metal cations in aqueous solution. The detection limits of Fe3+ and Cu2+ were calculated to be 143nM and 71.31μM, respectively. The LC–mass analysis indicated that 1:1 complex was formed between Fe3+ (or) Cu2+ and compound. Binding energy values for the complexation of the compound with metal ions are theoretically computed at M06/6–31+G(d,p) level. The DFT based binding energy values show good correlation with the experimental observations.