Sanmartín Matalobos, JesúsGarcía Deibe, Ana MaríaZarepour Jevinani, MortezaAboal Somoza, ManuelBermejo Barrera, PilarFondo Busto, María Matilde2020-10-292020-10-292020Sanmartín-Matalobos, J.; García-Deibe, A.; Zarepour-Jevinani, M.; Aboal-Somoza, M.; Bermejo-Barrera, P.; Fondo, M. Exploring the Chelating Potential of an Easily Synthesized Schiff Base for Copper Sensing. Crystals 2020, 10, 235http://hdl.handle.net/10347/23500The present study deals with the investigation of Cu2+, Ni2+ and Pd2+ chelating potential of the Schiff base, (E)-N-(2-((2-hydroxybenzylidene)amino)benzyl)-4-methylbenzenesulfonamide (H2SB). Crystal structures of Ni(HSB)2, Pd(HSB)2 and Cu(HSB)2 have been elucidated from single crystal X-ray diffraction data. NMR spectroscopy showed the presence of two conformers of Pd(HSB)2 in solution, both with an E configuration of the ligand. The determination of binding constants by fluorescence quenching showed that affinity of H2SB to Cu2+ in solution is higher than for Ni2+ and Pd2+. Since there is a high demand for selective, sensitive, rapid and simple methods to detect copper in aqueous samples (both as Cu2+ ions and as CuO NPs), we have explored H2SB as an optical chemosensor. H2SB interacts with increasing concentrations of Cu2+ ions, giving rise to a linear increase in the absorbance of a band centered at about 392 nm. H2SB displays a high selectivity toward Cu2+, even in the presence of the most common metal ions in water (Ca2+, Mg2+, Na+, K+, Al3+ and Fe3+), and some heavy transition metal ions such as the soft acids Pd2+ and Cd2+. H2SB also interacts with increasing concentrations of CuO NPs, which gives rise to a linear decrease in its fluorescence intensity (λem = 500 nm, λex = 390 nm). Quenching has occurred as a result of the formation of a non-fluorescent ground-state surface complex H2SB–CuO NPs. The limits of detection and quantification of CuO NPs were 9.8 mg/L and 32.6 mg/L, respectively. The presence of TiO2, Ag and Au NPs does not interfere with the determination of CuO NPseng© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)Atribución 4.0 Internacionalhttp://creativecommons.org/licenses/by/4.0/X-rayFluorescenceUV-VisCuO NPsCu2+ ionsSchiff basejournal article10.3390/cryst100302352073-4352open access