Synthesis, characterization and a thermal (TG-DSC) study of gadolinium and lutetium methanesulfonate coordination compounds with pyridine-N-oxide and 2-, 3- and 4-picoline-N-oxides

The synthesis, characterization and a thermal (TG and DSC) study of the coordination compounds Gd(MS)3·(py-NO)2, Gd(MS)3·(2-picNO)2, Gd(MS)3·(3-picNO)2, Gd(MS)3·(4-picNO)2, Lu(MS)3·(py-NO)2·2H2O, Lu(MS)3·(2-picNO)1.5·H2O, Lu(MS)3·(3-picNO) and Lu(MS)3·(4-picNO)2 are reported (MS = methanesulfonate, py-NO = pyridine-N-oxide, 2-picNO, 3-picNo and 4-picNO are 2-, 3- and 4-picoline-N-oxides, respectively). The observed thermal stability trend is: 2-picNO < py-NO < 4-picNO < 3-picNO for Gd and 2-picNO < 4-picNO < 3-picNO < py-NO for Lu. It was shown that the release of ligand molecules (endothermic) is followed by the thermal degradation of the ligands (exothermic).