Abstract
Abstract The spin-lattice relaxation times (T 1 ) of D and 17 O nuclei of D 2 O molecules in tetraalkylammonium bromides (R 4 NBr; R=Me, Et, Pr, Bu), dilute aqueous solutions were measured at the concentration of 0.2 to 1.0 mol/kg and at the temperature of 5 to 25 °C. The relative spin-lattice relaxation rate, R 1 /R 1 0 (R 1 =1/T 1 ) at 25 °C increased linearly with increasing concentration of tetraalkylammonium bromide solutions. But, it varied nonlinearly against the concentration below 20 °C and the deviation increased with decreasing temperature. The dynamic hydration number (n DHN ) of D and 17 O nuclei of a D 2 O molecule in the hydration sphere of tetraalkylammonium ions had good correlation with the molecular size, except for the Bu 4 N + ion. The deviation of n DHN of Bu 4 N + ion at low temperature reflected the caging effect due to the association through hydrogen bonding among water molecules as the association increases at lower temperature. It was suggested that the rotational anisotropy ( τ + D / τ + 170 ) of water molecules can be used as a new indicator to classify three types of hydration; negative, positive, and hydrophobic hydrations.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
