UV-vis spectral property of a multi-hydroxyl Schiff-base derivative and its colorimetric response to some special metal ions

A multi-hydroxyl Schiff-base derivative, N-2'-hydroxyl-1'-naphthyl methylene-2-amino phenol (HNMAP), was synthesized and characterized by FTIR, H-1 NMR and UV-vis spectroscopy. It was noted to find there was great effect for solvent and pH on the UV-vis spectroscopy of HNMAP. Especially, some metal ions could make its UV-vis spectra changed regularly with different time-resolved effects. For example, a real-time and multi-wavelength response to Fe2+ at 520 nm, 466 nm and 447 nm and a quite slow one about 26 min to Fe3+ at 447 nm and 466 nm, respectively. Under the optimized conditions, the changes in the corresponding absorption intensities at above wavelengths were in proportion to c(Fe)(2+) or c(Fe)(3+) during respectively partitioned linear ranges, which realized to quantitatively detect Fe2+ or Fe3+ with a large linear range more than two orders of magnitude. A 1:1 complex mode for HNMAP-Fe2+ and 1:2 for HNMAP-Fe3+ were proposed from UV-vis spectral titration and Job's plot. HNMAP would be a potential sensor for colorimetric detection of Fe2+ and Fe3+ in practice. (C) 2018 Elsevier B.V. All rights reserved.