NUCLEAR MAGNETIC RESONANCE STUDY OF THE TRANSVERSE RELAXATION OF OXYGEN 17 IN AQUEOUS SOLUTIONS OF TITANOUS ION

摘要

Oxygen-17 NMR has been used to study the solvation of Ti(III) innaqueous solution. The temperature and frequency dependence of the bulk 7water line width, l/T2, of the 017 NMR signal in aqueous solutions of titanous ion has been studied in the range 0℃ to ca. 70℃ at 1.999, 4.337, 6.086, and 8.134 MHz. The temperature dependence of the bound wa¬ter lincwidth, 1/T2, was studied in the range +2 • to -30℃ at 8.134 MHz. The chemical shifts of both the bulk and bound waters were measured as a function of temperature at 8.134 MHz. The former was studied in the range 0 to 70℃ and the latter in the range +2 to -30℃.nBelow 12℃, at 8.134 MHz, the broadening becomes increasingly controlled by the lifetime of the water molecules in the first coordi¬nation sphere of Ti(III). In this region the enthalpy and entropy of activation for the water-water exchange of this system have been cal¬culated to be 7.7 kcal/mole and -9 eu respectively.