Decorated crown ethers as selective ion traps: Solvent's role in crown's preference towards a specific ion

Deviation of sodium and potassium concentrations from their optimal values in living organisms is asso-ciated with severe health conditions, thus their precise determination in blood samples requires design of sensitive sensors. Additionally, excess of the two alkali cations should be removed from drinking water. Crown ethers are well-known metal ion traps, as careful choice of crown's size and its substituents might tune it towards favoring a specific ion. It has been proved experimentally that dibrominated bithiophene crown ethers with five and six oxygen atoms selectively capture the Na' and the K' ion, respectively (Giovannitti et al., Adv. Funct. Mater. 26, 2016, 514) in acetonitrile solution. In the present contribution, we analyzed the nature of ion-crown, ion-solvent, and crown-solvent interactions, and demonstrated that the solvent molecules are responsible for the decorated crown's preference for a particular alkali cation. While past research focused on the ring size and the ion radius compatibillity, which is important for a formation of a stable ion-crown complex, our findings highlight the decisive role of solvent mole-cules in the selectivity of crown ethers toward particular cations.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

Deviation of sodium and potassium concentrations from their optimal values in living organisms is associated with severe health conditions. Thus, sensitive sensors are required for the precise determination of these ions in blood samples. Besides, excess sodium and potassium should be removed from drinking water. In this study, the role of solvent molecules in the selectivity of crown ethers toward specific cations is analyzed and highlighted.