Complexation thermodynamics of UO22+/diglycolamide complex in a room temperature ionic liquid: A study by optical spectroscopy and microcalorimetry. (1st July 2022)

• Record Type: Journal Article
• Authors: Ansari, Seraj A.; Dumpala, Rama Mohana R.; Verboom, Willem; Mohapatra, Prasanta K.
• Is Part Of: Polyhedron. Volume 220(2022)
• Publication Date: 2022-07-01
• Subjects: Complexation -- Actinides -- Diglycolamide -- Ionic liquid -- Calorimetry; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2022.115820
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: Complexation thermodynamics of UO2 2+ and a series of N, N, N', N' -teraalkyl diglycolamide (T R DGA) ligands were investigated in Bumim⋅Tf2 N, an ionic liquid (IL). The structural feature indicated the formation of the [UO2 L2 ] 2+ type of complex without any water or Tf2 N − anion in the primary coordination sphere of the uranyl cation. Abstract: Complexation thermodynamics of UO2 2+ and a series of N, N, N', N' -tetraalkyl diglycolamide (T R DGA) ligands having alkyl chains –CH3 to –C6 H13 were investigated in an ionic liquid (IL). The complexation constant for UO2 2+ /DGA complex increased linearly with increasing alkyl chain length of DGA from tetramethyl (log β1 = 4.52, log β2 = 8.01) to tetrahexyl (log β1 = 5.62, log β2 = 10.3). There were two types of species recorded in the calorimetric titration for all the four ligands, one having endothermic complexation, and other exothermic. This observation was in contrast with those observed for aqueous medium, where both the stepwise complexation enthalpies were endothermic. The structural feature indicated the formation of [UO2 L2 ] 2+ type of complex without water or Tf2 N − anion in the primary coordination sphere of the uranyl cation.