title: Fluorescent chemosensor based on sensitive Schiff base for selective detection of Zn2+.
abstract: A Schiff-base fluorescent compound - N, N'-bis(salicylidene)-1,2 - phenylenediamine (LH2) was synthesized and evaluated as a chemoselective Zn(2+) sensor. Addition of Zn(2+) to ethanol solution of LH2 resulted in a red shift with a pronounced enhancement in the fluorescence intensity. Moreover, other common alkali, alkaline earth and transition metal ions failed to induce response or minimal spectral changes. Notably, this chemosensor could distinguish clearly Zn(2+) from Cd(2+). Fluorescence studies on free Schiff base ligand LH2 and LH2 - Zn(2+) 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.
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
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.
authors.forename: Harun A R
authors.initials: HA
authors.lastname: Pramanik
mesh_terms: D005456:Fluorescent Dyes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D008027:Light; D012545:Schiff Bases / Q000138:chemical synthesis / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D015032:Zinc / Q000032:analysis*
chemical_list: D005456:Fluorescent Dyes; D008024:Ligands; D012545:Schiff Bases; D012997:Solvents; D015032:Zinc
keywords: Chemosensor; Fluorescence; Schiff base; Selectivity; Zn(2+)