Work

A Two‐Step Intermolecular Interaction Of Molecular Macroions With Multivalent Counterions

Year: 2024

Type: article

Abstract: Macroion‐counterion interaction is essential for regulating the solution behaviors of hydrophilic macroions, as simple models for polyelectrolytes. Here, we explore the interaction between uranyl peroxide molecular cluster Li68K12(OH)20[UO2(O2)OH]60 (U60) and multivalent counterions. Different from interaction with monovalent counterions that shows a simple one‐step process, isothermal titration calorimetry, combined with light/X‐ray scattering measurements and electron microscopy, confirm a two‐step process for their interaction with multivalent counterions: an ion‐pairing between U60 and the counterion with partial breakage of hydration shells followed by strong U60‐U60 attraction, leading to the formation of large nanosheets with severe breakage and reconstruction of hydration shells. The detailed studies on macroion‐counterion interaction can be nicely correlated to the microscopic (self‐assembly) and macroscopic (gelation or phase separation) phase transitions in the dilute U60 aqueous solutions induced by multivalent counterions.

Source: Chemistry - A European Journal

DOI: 10.1002/chem.202402359