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- On the development of selective chelators for Cadmium: Synthesis, structure and chelating properties of 3-((5-(trifluoromethyl)-1,3,4-thiadiazol-2-yl)amino)benzo[d]isothiazole 1,1-dioxide, a novel Thiadiazolyl SaccharinatePublication . Leal, Joana F.; Guerreiro, Bruno; Amado, Patrícia; Fernandes, André L.; Barreira, Luísa; Paixão, José A.; Lurdes S. Cristiano, M.Aquatic contamination by heavy metals is a major concern for the serious negative consequences it has for plants, animals, and humans. Among the most toxic metals, Cd(II) stands out since selective and truly efficient methodologies for its removal are not known. We report a novel multidentate chelating agent comprising the heterocycles thiadiazole and benzisothiazole. 3-((5-(trifluoromethyl)-1,3,4-thiadiazol-2-yl)amino)benzo[d]isothiazole 1,1-dioxide (AL14) was synthesized from cheap saccharin and characterized by different techniques, including single crystal X-ray crystallography. Our studies revealed the efficiency and selectivity of AL14 for the chelation of dissolved Cd(II) (as compared to Cu(II) and Fe(II)). Different spectral changes were observed upon the addition of Cd(II) and Cu(II) during UV-Vis titrations, suggesting different complexation interactions with both metals.
- Solvent-free oxidation of benzyl alcohols catalysed by a tetrazole-saccharinate Zn(II) complex under microwave radiation: the role of the ligand and the reaction mechanismPublication . Frija, Luis M. T.; Fernandes, André L.; Cristiano, Maria L.S.; Pombeiro, Armando J. L.Herein we present an efficient methodology for the microwave-assisted peroxidative oxidation of benzyl alcohols to the corresponding aldehydes by using a novel and stable tetrazole-saccharinate zinc(II) catalyst, along with some insights into the reaction mechanism. This methodology is distinguished by the use of easily available and cheap reagents on the genesis of the zinc catalyst, mild reaction conditions, very short reaction periods (5-20 min) and no need to add an organic solvent. Furthermore, the use of TBHP (70%. aq.) as oxidizing agent turn this protocol a convenient one for benzyl alcohol oxidation in yields up to 98%. (C) 2020 Elsevier B.V. All rights reserved.