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

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 (Ka) 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.