Complexation thermodynamics of UO22+ and a series N,N,N’,N’-tetraalkyl diglycolamide (TRDGA) ligands having alkyl chains –CH3 to –C6H13 were investigated in an ionic liquid (IL). The complexation constant for UO22+/DGA complex increased linearly with increasing chain length DGA from tetramethyl (logβ1 = 4.52, logβ2 8.01) tetrahexyl 5.62, 10.3). There two types species recorded the calorimetric ...