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A pyridine based imine-linked chemosensor has been synthesized and evaluated its binding affinity with library of transition metal ions. It has prominent selectivity towards Pb among other metal ions in DMF/HO (9:1, v/v) solvent system. The 1:1 stoichiometric was confirmed by job's plot and has a binding constant (K) = 5.142 × 10 M on fluorescence. A B3LYP/6-31G and B3LYP/LanL2DZ basis sets were employed for optimization of 3 and 3.Pb. [ABSTRACT FROM AUTHOR]

Urea based fluorescent chemosensor 1 was synthesized. Receptor 1 shows unique selectivity for the Feion and no such significant response was noticed with other metal ions (Cr, Mn, Co, Ni, Cu, Zn, Cd, Hg, Pb and Bi) in DMSO/HO (50:50,v/v) semi-aqueous solution. The binding features have been established by absorption and fluorescence spectroscopic methods. The binding constant (K) values obtained from Benesi-Hildebrand, Scatchard and Connor plot for receptor 1 is (8.3 ± 0.3) × 10 M and has good detection limit 0.7 μM. The stoichiometry of 1.Fe complex was confirmed by mass spectroscopy and Job's plot. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Highlights: [•] We synthesized a fluorescence receptor (2) and report it as a photoinduced electron transfer (PET) cation sensor. [•] The association constant (K) of receptor (2) with Fe3+ ions was calculated at 1.4±0.2×104 M−1. [•] The 1:1 stoichiometry of the host guest relationship was realized from the Job’s plot. [ABSTRACT FROM AUTHOR]

A linear Schiff-based receptor (L) containing two imino phenol units was developed for the selective fluorescent sensing of Zn2+ with a discriminating enhancement of 12-folds over the other surveyed cations. Within the huge plethora of Zn2+ receptors, this receptor is quite worth to mention because of its simple synthesis, low cost, no interference of Cd2+ and the judicious response availed with discernment. The spectroscopic (UV-Vis, fluorescence and mass) results, few mathematical models for determining analytical parameters such as binding constant (Ka), binding stoichiometry, detection limit, etc. and the frontier molecular orbitals were analyzed to explore the sensing ability of L and the mechanism. [ABSTRACT FROM AUTHOR]