title: A highly sensitive and selective fluorescent chemosensor for detection of Zn2+ based on a Schiff base.
abstract: A Schiff-base fluorescent probe - 2-((E)-(quinolin-8-ylimino)methyl)quinolin-8-ol (H7L) was synthesized and evaluated as a chemoselective Zn2+ sensor. Upon treatment with Zn2+, the complexation of H7L with Zn2+ resulted in a red shift with a pronounced enhancement in the fluorescence emission intensity in ethanol solution. Moreover, other common alkali, alkaline earth and transition metal ions failed to induce response or minimal spectral changes. Notably, this chemosensor could distinguish clearly Zn2+ from Cd2+. Fluorescence studies on H7L and H7L-Zn2+ complex reveal that the quantum yield strongly increases upon coordination. The stoichiometric ratio and association constant were evaluated using Benesi-Hildebrand relation giving 1:1 stoichiometry. This further corroborated 1:1 complex formation based on Job's plot analyses. This chemosensor exhibits a very good fluorescence sensing ability to Zn2+ over a wide range of pH.
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: Harun A R
authors.initials: HA
authors.lastname: Pramanik
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. Electronic address: takhelsingh@gmail.com.
authors.forename: T Sanjoy
authors.initials: TS
authors.lastname: Singh
mesh_terms: D002413:Cations, Divalent / Q000032:analysis; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D015125:Oxyquinoline / Q000138:chemical synthesis / Q000737:chemistry*; D012545:Schiff Bases / Q000138:chemical synthesis / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D015032:Zinc / Q000032:analysis*
chemical_list: D002413:Cations, Divalent; D005456:Fluorescent Dyes; D012545:Schiff Bases; D015125:Oxyquinoline; D015032:Zinc
keywords: Binding constant; Fluorescence; Schiff base; Selectivity; Zn(2+) ion