Solvent effects on complexation of crown ethers with LiClO4, NaClO4 and KClO4 in methanol and acetonitrile

D'Aprano, Alessandro; Salomon, Mark; Mauro, Vincenzo

doi:10.1007/bf00973236

Cited by 36 publications

(10 citation statements)

References 39 publications

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“…14 They have fit this system for the formation of only a 1 : 1 complex. D'Aprano, Salomon, and Mauro 16 have proposed a different mechanism where the presence of two other species in the solution, the ion pair Li C ClO 4 2, and the reassociation pair Li C 12C4ClO 4 4 are considered significant. The mechanism that they propose is as follows:…”

Section: The 1 : 1 Vs the 1 : 1 + 1 : 2 Modelmentioning

confidence: 98%

“…29 The Solomon data are interesting in that they give rise to a proposal of contributions of the recomplexation to stability constants. 16 The problem is that there is no way to determine what combination of aggregative phenomena is taking place in condensed phase reactions. It is likely that all four of these interactions are taking place and, perhaps, more.…”

Section: The 1 : 1 Vs the 1 : 1 + 1 : 2 Modelmentioning

confidence: 99%

See 1 more Smart Citation

Stability constants: comparative study of fitting methods. Determination of second‐order complexation constants by²³Na and⁷Li NMR chemical shift titration

Masiker

Mayne

Eyring

2006

Magnetic Reson in Chemistry

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NMR chemical shift titration has been widely used as a method for the determination of stability constants. Systems involving metal-ligand complexation have been investigated using a number of methodologies. There are significant differences in the values reported for stability constants obtained by different experimental methods, such as calorimetry and ion selective electrode (ISE) titrations; nor has NMR chemical shift titration always yielded consistent results. Different researchers have obtained different results for the same system with results differing by as much as an order of magnitude. The chemical shift data are generally plotted against the concentration ratio of the metal and ligand for a set of solutions. A nonlinear least squares fitting method using an analytical solution of the cubic equation for the equilibrium concentration of the free ligand is used in this study and compared with methods used in the literature. Second-order association constants for the LiClO(4):12-crown-4 system in acetonitrile and the NaClO(4):12-crown-4 system in methanol are reported. Formation of both 1:1 and 1:2 metal-ligand complexes are considered. The LiClO(4):12-crown-4 acetonitrile system had been investigated previously by NMR titration but only 1:1 complexation was considered in that study. This study provides convincing evidence that both 1:1 and 1:2 complexes are important, at least, in the lithium system. A Monte Carlo investigation of the propagation of errors from the chemical shifts to the stability constants shows that the choice of data analysis methods may, in part, contribute to discrepancies and that the nonlinear nature of the model can dramatically affect the error limits on the stability constants.

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Section: The 1 : 1 Vs the 1 : 1 + 1 : 2 Modelmentioning

confidence: 98%

Section: The 1 : 1 Vs the 1 : 1 + 1 : 2 Modelmentioning

confidence: 99%

Stability constants: comparative study of fitting methods. Determination of second‐order complexation constants by²³Na and⁷Li NMR chemical shift titration

Masiker

Mayne

Eyring

2006

Magnetic Reson in Chemistry

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“…Crown ethers are a class of ligands known to bind various cations depending, in part, on the relative size of their cavity and the size of the target ion (35). For example, 12-crown-4 ether (12C4) forms reversible complexes with both Na + and Li + ions, where the relative affinity depends on the chemical environment (35)(36)(37)(38). Some researchers have reported selective Li + transport by incorporating crown ethers into supported liquid membranes (34,39,40).…”

Section: Significancementioning

confidence: 99%

Engineering Li/Na selectivity in 12-Crown-4–functionalized polymer membranes

Warnock

Sujanani

Zofchak

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

111

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Lithium is widely used in contemporary energy applications, but its isolation from natural reserves is plagued by time-consuming and costly processes. While polymer membranes could, in principle, circumvent these challenges by efficiently extracting lithium from aqueous solutions, they usually exhibit poor ion-specific selectivity. Toward this end, we have incorporated host–guest interactions into a tunable polynorbornene network by copolymerizing 1) 12-crown-4 ligands to impart ion selectivity, 2) poly(ethylene oxide) side chains to control water content, and 3) a crosslinker to form robust solids at room temperature. Single salt transport measurements indicate these materials exhibit unprecedented reverse permeability selectivity (∼2.3) for LiCl over NaCl—the highest documented to date for a dense, water-swollen polymer. As demonstrated by molecular dynamics simulations, this behavior originates from the ability of 12-crown-4 to bind Na+ ions more strongly than Li+ in an aqueous environment, which reduces Na+ mobility (relative to Li+) and offsets the increase in Na+ solubility due to binding with crown ethers. Under mixed salt conditions, 12-crown-4 functionalized membranes showed identical solubility selectivity relative to single salt conditions; however, the permeability and diffusivity selectivity of LiCl over NaCl decreased, presumably due to flux coupling. These results reveal insights for designing advanced membranes with solute-specific selectivity by utilizing host–guest interactions.

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“…[13][14][15][16][17][18] Use of its hydrogen derivative HCN is mostly prevented by its high toxicity and its boiling point of 25°C. Experimental studies dating back to the middle of the 20th century show that HCN is a water-like solvent that is well suited for dissolving organic and inorganic compounds.…”

Section: Introductionmentioning

confidence: 99%

Ligand‐Exchange Processes on Solvated Lithium Cations: Acetonitrile and Hydrogen Cyanide

et al. 2007

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Solvent effects on complexation of crown ethers with LiClO4, NaClO4 and KClO4 in methanol and acetonitrile

Cited by 36 publications

References 39 publications

Stability constants: comparative study of fitting methods. Determination of second‐order complexation constants by²³Na and⁷Li NMR chemical shift titration

Stability constants: comparative study of fitting methods. Determination of second‐order complexation constants by²³Na and⁷Li NMR chemical shift titration

Engineering Li/Na selectivity in 12-Crown-4–functionalized polymer membranes

Ligand‐Exchange Processes on Solvated Lithium Cations: Acetonitrile and Hydrogen Cyanide

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Solvent effects on complexation of crown ethers with LiClO4, NaClO4 and KClO4 in methanol and acetonitrile

Cited by 36 publications

References 39 publications

Stability constants: comparative study of fitting methods. Determination of second‐order complexation constants by23Na and7Li NMR chemical shift titration

Stability constants: comparative study of fitting methods. Determination of second‐order complexation constants by23Na and7Li NMR chemical shift titration

Engineering Li/Na selectivity in 12-Crown-4–functionalized polymer membranes

Ligand‐Exchange Processes on Solvated Lithium Cations: Acetonitrile and Hydrogen Cyanide

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Stability constants: comparative study of fitting methods. Determination of second‐order complexation constants by²³Na and⁷Li NMR chemical shift titration

Stability constants: comparative study of fitting methods. Determination of second‐order complexation constants by²³Na and⁷Li NMR chemical shift titration