On a Study of Spinhyphen;Lattice Relaxation Times of19F,31P,1H, and2H in Solutions ofPF6minus;and PO3F2minus;in D2O and H2O

摘要

The spinhyphen;lattice relaxation times of fluorine, phosphorus, protons, and deuterons in solutions of sodium hexafluorophosphate and sodium monofluorophosphate in water and deuterium oxide have been measured at 25 MHz by pulsed techniques over the temperature range 250ndash;363deg;K. The fluorine and phosphorus spinhyphen;lattice relaxation times in both salt solutions have been found to be the sum of interactions due to spinhyphen;rotation and dipolehyphen;dipole contributions. The spinhyphen;rotation constants for fluorine and phosphorus inPF6minus;are 3.56 and 3.86 kHz, respectively. The spinhyphen;rotation constants for fluorine and phosphorus in PO3F2minus;are 23.6 and 21.4 kHz. Spinhyphen;rotation constants were also calculated from chemical shielding data. The results for the nearly sphericalPF6minus;anion are in accord with rotation diffusion theory. The31P relaxation data seem to indicate that thePF6minus;anion follows theJhyphen;diffusion model of McClung whereas the19F relaxation data indicate that theMhyphen;diffusion model is followed. The reorientation correlation times of water and deuterium oxide molecules have also been determined for solutions containingPF6minus;and PO3F2minus;ions. These ions seem to affect the correlation times of the H2O and D2O molecules differently.