title: Coumarin Based Fluorescent Probe for Colorimetric Detection of Fe3+and Fluorescence Turn On-Off Response of Zn2+and Cu2.
abstract: A new coumarin based Schiff-base chemosensor-(E)-7-(((8-hydroxyquinolin-2-yl)methylene) amino)-4-methyl-2H-chromen-2-one (H11L) was synthesized and evaluated as a colorimetric sensor for Fe3+and fluorescence "turn on-off" response of Zn2+and Cu2+using absorption and fluorescence spectroscopy. Upon treatment with Fe3+and Zn2+, the absorption intensity as well as the fluorescence emission intensity increases drastically compared to other common alkali, alkaline earth and transition metal ions, with a distinct color change which provide naked eye detection. Formation of 1:1 metal to ligand complex has been evaluated using Benesi-Hildebrand relation, Job's plot analyses,1H NMR titration as well as ESI-Mass spectral analysis. The complex solution of H11L with Zn2+ion exhibited reversibility with EDTA and regenerate free ligand for further Zn2+sensing. H11L exhibits two INHIBIT logic gates with two different chemical inputs (i) Zn2+(IN1) and Cu2+(IN2) and (ii) Zn2+(IN1) and EDTA (IN2) and the emission as output. Again, an IMPLICATION logic gate is obtained with Cu2+and EDTA as chemical inputs and emission as output mode. Both free ligand as well as metal-complexes was optimized using density functional theory to interpret spectral properties. The corresponding energy difference between HOMO-LUMO energy gap for H11L, H11L-Zn2+and H11L-Cu2+are 2.193, 1.834 and 0.172 eV, respectively.
authors.affiliation: Department of Chemistry, Assam University, Silchar, Assam, 788 011, India.
authors.forename: Nayan
authors.initials: N
authors.lastname: Roy
authors.affiliation: Department of Chemistry, Assam University, Silchar, Assam, 788 011, India.
authors.forename: Abhijit
authors.initials: A
authors.lastname: Dutta
authors.affiliation: Department of Chemistry, Assam University, Silchar, Assam, 788 011, India.
authors.forename: Paritosh
authors.initials: P
authors.lastname: Mondal
authors.affiliation: Department of Chemistry, Assam University, Silchar, Assam, 788 011, India.
authors.forename: Pradip C
authors.initials: PC
authors.lastname: Paul
authors.affiliation: Department of Chemistry, Assam University, Silchar, Assam, 788 011, India. takhelsingh@gmail.com.
authors.forename: T
authors.initials: T
authors.lastname: Sanjoy Singh
keywords: Binding constant; Chemosensor; Density functional theory; Fluorescence; Logic function; Selectivity