2002
"Aroylthioureas: new organic ionophores for heavy metal ion selective electrodes. A nuclear magnetic resonance study", E. Otazo-Sanchez, P. Ortiz del Toro, O. Estevez-Hernandez, L. Perez marin, I. Goicoechea, A. Ceron Beltran y J.R. Villagomez Ibarra. Spectrochimica Acta Part A 58 (2002) 2281-2290
Abstract
The 1H and 13C NMR spectra of four series of 1-aroylthiourea derivatives in DMSO-d6 are reported. The NH signals for 3-alkyl substituted aroylthioureas are identified by their multiplicity and by homonuclear irradiation experiments. Correlation analyzes are made for NH, CO and CS signals in order to determine the best way to modulate the nucleophilic character of the CS group, as thioureas are well-known ionophore groups. Almost all 1,3-substituted thioureas (Series 24) show the reported chelated structure with the exception of those with CF3, CN and NO2 groups. Pyridine group promote a different equilibrium in solution. The fragment ?CO?NH? transmits poorly the electronic effects of substituents in the aroylgroup
Antioxidant constituents from Geranium bellum Rose
Estudio químico de cinco plantas mexicanas de uso común en la medicina tradicional
Effect of the particle size on the activity of MoOxCy catalysts for the isomerization of heptane
Lead, Cadmium and Cobalt (Pb, Cd, and Co) Leaching of Glass-Clay Containers by pH Effect of Food