The examination of a variety of different ions added to the crown ether derivatives with high field NMR spectrometer

Abstract

The current study involves the measurements of T₁ relaxation time of complexes three different crown ethers (4-aminobenzo-15-Crown-5, 1-Aza-18-Crown-6, 1-Aza-15-Crown-5) and two different ions sodium perchlorate (NaClO₄), lithium perchlorate (LiClO₄) by a 400 MHz NMR spectrometer. The association constants (K_a) of the complexes were determined on the basis of the evaluation of these measurements using the Benesi-Hildebrand method that we have modified. These association constants were consistent with those obtained from ¹H NMR titration technique. As a result, it can be speculated that binding constants could be measured using T₁ relaxation time when chemical shifts are very small or cannot be observed.