Exchange kinetics of the sodium cation with dibenzo-24-crown-8 in nitromethane solution: competition between unimolecular decomplexation and bimolecular cation interchange mechanisms

Investigation of the mechanism of sol-gel formation in the Sr(NO3)2/citric acid/ethylene glycol system by solution state 87 Sr nuclear magnetic resonance spectroscopy

“…The qualitative interpretation of NMR data related to molecular dynamics typically involves utilization of models for the kinetic study. To date, NMR has been used to characterize the mechanism by which small organic complexing agents exchange host metal cation for Na + (I ‫ס‬ 3/2), [12][13][14][15] K + (I ‫ס‬ 3/2), [13][14][15][16] Cs + (I ‫ס‬ 7/2), 14,17,18 and others. In these studies, the variation of chemical shift as a function of the ratio of the complexing agent to the metal ions has been used to determine the complexation number.…”

High-contrast Cu(i)-selective fluorescent probes based on synergistic electronic and conformational switching

“…20,21 As illustrated with Figure 4, Cu(I) binding resulted in large shifts of the aniline proton resonances. In agreement with pyramidalization of the aniline nitrogen upon Cu(I) binding, the chemical shift changes of the ortho- and para-substituted proton resonances (labeled as H a and H c in Fig.…”

“…21,23 A plot of the observed exchange rate constants versus the total ligand concentration yielded the bimolecular rate constant k 1 = 2 × 10 6 s −1 M −1 (Figure 4C). Based on these data, we obtained an average lifetime τ = 1/ k a of 200 ms for ligand-bound Cu(I) in an equimolar mixture of complex and ligand at a concentration of 5 μM, which was used for the fluorescence experiments.…”

Lithium-7 NMR Study of the Exchange Kinetics of the Lithium Ion With Crypt and C221 in Nitromethane and Dimethylformamide Solutions

“…It should be noted that, in order for a bimolecular metal exchange to proceed in a metal-macrocycle system, the simultaneous arrival of a new metal and departure of the complexed cation should be facilitated. 24 Since with either exchange mechanism the reciprocal of is proportional to the decomposition rate, a plot of In k d vs. 1/T gives an Arrhenius plot. A similar conclusion has been made previously.…”