QUADRATIC ACID AS A STRUCTURAL MOTIVE IN A LEHN-TYPE CRYPTAND - PREDICTION OF ION SELECTIVITY BY QUANTUM CHEMICAL CALCULATIONS. XX. - Capponi, Thomas; Khairbek, Ali A.; Ćoćić, Dušan; Soldatović, Tanja; Puchta, Ralph; van Eldik, Rudi (Kragujevac Journal of Science, 2025)